JP3872121B2 - In-cylinder direct injection multi-cylinder engine control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an in-cylinder direct injection multi-cylinder engine that reduces the burden of a driving power source on an in-cylinder direct injection fuel injection valve.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an in-cylinder direct injection engine that obtains output by directly injecting fuel (gasoline) pressurized to a high pressure into a cylinder and spark ignition is known. In this type of direct injection engine, a large amount of fuel must be injected in a short injection time. Therefore, it is necessary to set the fuel injection valve with high responsiveness. Up current ") is applied to ensure the startup characteristics when the injection valve is open.
[0003]
In-cylinder direct injection engines can perform lean combustion by stratified combustion, but during stratified combustion, the amount of surplus air is large, and the exhaust gas temperature tends to be lowered accordingly, so that the catalyst is difficult to activate.
[0004]
As a means for increasing the exhaust gas temperature during stratified combustion to promote catalyst activation, for example, in Japanese Patent Laid-Open No. 4-272448, a post-injection is added immediately after combustion, and the catalyst is passed by the combustion by this post-injection. The exhaust gas temperature is raised.
[0005]
[Problems to be solved by the invention]
However, in the one-time injection in one cycle, if the combustion method is constant, the energization period for the fuel injection valve will not overlap between the cylinders. There is a case where the energization period required for the operation overlaps with the energization period during normal injection of other cylinders.
[0006]
In addition, in a direct injection engine that performs control to switch the combustion system from stratified combustion to uniform combustion according to the load fluctuation during operation, the injection timing changes significantly when the combustion system is switched. Energization may overlap between cylinders.
[0007]
If the energization periods for the fuel injection valve overlap, the current consumption becomes excessive, the voltage of the drive power supply drops, the needle lift of the fuel injection valve becomes insufficient, or the operation fails, and the appropriate fuel There is an inconvenience that an injection amount cannot be obtained and combustion worsens or misfires occur. Particularly, since the pull-up current for opening the fuel injection valve is a large current, if this pull-up current overlaps between cylinders, the malfunction of the fuel injection valve becomes more prominent.
[0008]
In order to cope with this, it is conceivable to increase the capacity of the driving power supply, but there is a problem that the cost is increased and the durability is relatively lowered due to the increased capacity.
[0009]
The present invention has been made in view of the above circumstances, and can reduce the burden of the power source for driving the fuel injection valve, can always supply an appropriate amount of fuel injection, and can further increase the capacity of the driving power source. It is an object of the present invention to provide a control device for a direct injection type multi-cylinder engine that is low in cost and excellent in durability without being increased.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, as shown in FIG. 1, in a direct injection type multi-cylinder engine in which fuel is directly injected into a cylinder of each cylinder and burned, the high pressure of one cylinder One of the other cylinders and a pull-up current end determining means for determining whether the energization of the valve-opening pull-up current to the fuel injection valves of the other cylinders is completed when starting energization of the fuel injection valves for the other cylinders When the pull-up current is being applied to the fuel injection valve of the cylinder, after the energization of the pull-up current of the cylinder is finished, the fuel injection valve of the one cylinder is set so that only the energization period of the pull-up current does not overlap. And a fuel injection valve energization control means for starting energization.
[0011]
According to a second aspect of the present invention, in the control device for a direct injection type multi-cylinder engine according to the first aspect, the stratified combustion determination means for determining the selection of the stratified combustion based on the engine operating state, and the selection of the stratified combustion And an ignition timing changing means for retarding the ignition timing of the cylinder in response to a change in the start of energization of the fuel injection valve of the one cylinder.
[0012]
That is, in the first aspect of the invention, when energization is started for the fuel injection valve of the current fuel injection target cylinder, which is one cylinder, a pull-up for opening the fuel injection valve in the other cylinders It is determined whether the current is energized, and when the pull-up current is energized for the fuel injection valves of other cylinders, the pull-up current Energization is started for the fuel injection valve of the current fuel injection target cylinder so that only the energization period does not overlap. As a result, in the fuel injection valve driving power source, since the energization period of the pull-up current that requires a large current does not overlap between the cylinders, the burden is reduced.
[0013]
In the second aspect of the invention, in the first aspect of the invention, when stratified combustion is selected as the combustion mode, the ignition timing of the cylinder is delayed in response to the change in the start of energization of the fuel injection valve of the cylinder. Horn. As a result, the burden on the driving power source is reduced, and the interval between the fuel injection end timing and the ignition timing required during stratified combustion is always properly maintained.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the drawings. Reference examples and An embodiment will be described.
[0015]
The present invention is shown in FIGS. Reference example Indicates. First, an overall outline of an in-cylinder direct injection multi-cylinder engine including a fuel supply system will be described with reference to FIG.
[0016]
Book Reference example An in-cylinder direct injection multi-cylinder engine (hereinafter simply referred to as “engine”) 1 shown in FIG. 1 is a two-cycle four-cylinder gasoline engine, and is formed by a cylinder head 2, a cylinder block 3, and a piston 4 of the engine 1. For each cylinder combustion chamber 5, an ignition plug 7 connected to the secondary side of the ignition coil 6a and a high-pressure injector 8 that is a fuel injection valve are faced, and an igniter 6b is provided on the primary side of the ignition coil 6a. It is connected.
[0017]
Further, a scavenging port 3 a and an exhaust port 3 b are formed in the cylinder block 3, and a water temperature sensor 9 is exposed in a cooling water passage 3 c formed in the cylinder block 3. An air supply pipe 10 communicates with the scavenging port 3a. An air cleaner 11 is attached to the air supply pipe 10 on the upstream side, and a scavenging pump 12 is interposed in the middle. The scavenging pump 12 is an engine-driven type that is linked to the crankshaft 1 a, and fresh air is forcibly supplied to the combustion chamber 5 by the operation of the scavenging pump 12, and the combustion chamber 5 is scavenged.
[0018]
Further, a bypass passage 13 that bypasses the scavenging pump 12 is connected to the air supply pipe 10, and a throttle valve 15 a is interposed in the air supply pipe 10 upstream of the inflow port of the bypass passage 13. An accelerator opening sensor 16 for detecting an accelerator opening (= throttle opening) α is connected to an accelerator pedal 14 for operating the throttle valve 15a. On the other hand, a bypass control valve 15 b that controls the scavenging air pressure of the scavenging pump 12 is interposed in the bypass passage 13.
[0019]
The exhaust port 3b is provided with an exhaust rotary valve 17 that controls the exhaust timing by opening and closing in synchronization with the rotation of the crankshaft 1a. An exhaust pipe 18 communicates with the exhaust port 3b through the exhaust rotary valve 17. Has been. Further, a catalyst 19 is interposed in the exhaust pipe 18 and a muffler 20 is connected to the downstream end.
[0020]
Further, as shown in FIG. 19, a crank angle detecting crank rotor 21a and a cylinder discriminating crank rotor 21b are mounted on the crankshaft 1a at predetermined intervals, and both the crank rotors 21a, 21b are mounted. A crank angle sensor 22a and a cylinder discrimination sensor 22b made of an electromagnetic pickup or the like are provided with a predetermined gap S on the outer periphery of the cylinder.
[0021]
As shown in FIG. 20, the crank angle detecting crank rotor 21a is formed with a plurality of crank angle detecting projections 21c. Book Reference example The engine 1 shown in FIG. 2 is a 2-cycle 4-cylinder engine, and if the combustion is performed at equal intervals, the top dead center TDC of each cylinder is set every 90 ° CA, and the ignition order is # 1 → # 4 → # 3 → # 2. Then, the crank angle detection projections 21c are formed at the crank angles θ1 to θ3 in the advance direction (counterclockwise direction in the figure) from the top dead center TDC of each cylinder. The positions of the crank angle detection protrusions are, for example, θ1 = BTDC (before top dead center) 75 ° CA, θ2 = BTDC 45 ° CA, θ3 = BTDC 15 ° CA, that is, each crank angle detection protrusion 21c is BTDC15. They are formed at a constant pitch of 30 ° CA on the circumference from the position of ° CA.
[0022]
Further, as shown in FIG. 21, a cylinder discrimination projection 21d is formed on the outer periphery of the cylinder discrimination crank rotor 21b. Book Reference example Then, three cylinder discrimination protrusions 21d are formed, and two of these cylinder discrimination protrusions 21d are positioned at θ4 and θ5 in the advance direction with reference to the top dead center TDC of the # 1 cylinder. Is formed. Further, another cylinder discrimination projection 21d is formed at the position of θ6 in the advance direction with reference to the top dead center TDC of the # 3 cylinder. Book Reference example Then, the crank position of each cylinder discrimination projection 21d is, for example, θ4 = BTDC60 ° CA, θ5 = BTDC30 ° CA, and θ6 = BTDC60 ° CA.
[0023]
The crank angle sensor 22a is provided at a position indicating the top dead center TDC of the crank angle detection crank rotor 21a, while the cylinder determination is performed at a position indicating the top dead center TDC of the cylinder determination crank rotor 21b. A sensor 22b is provided oppositely, and the crank angle detecting projection 21c of the crank angle detecting crank rotor 21a is opposed to the crank angle sensor 22a by the rotation of the crankshaft 1a, or the cylinder determining crank rotor 21b. When the cylinder discriminating projection 21d faces the cylinder discriminating sensor 22b, as shown in FIG. 19, the gap S between the sensors 22a, 22b and the tops of the projections 21c, 21d of the crank rotors 21a, 21b. Is set to, for example, 0.8 ± 0.4 (mm).
[0024]
As shown in FIG. 18, both the sensors 22a and 22b are arranged with a predetermined clamping angle. However, in FIGS. It shows in a state where the top dead centers of 21b correspond to each other.
[0025]
Further, the projections 21c and 21d of the crank rotors 21a and 21b are detected by the sensors 22a and 22b in synchronization with the rotation of the crankshaft 1a, and the crank pulse and the cylinder discrimination pulse output from the sensors 22a and 22b are detected. 27 to 29, the cylinder discrimination pulse of BTDCθ4 of the # 1 cylinder (hereinafter referred to as “θ4 pulse”) is the crank pulse of BTDCθ1 of the # 1 cylinder (hereinafter referred to as “ The cylinder discrimination pulse (hereinafter abbreviated as “θ5 pulse”) of BTDCθ5 is interrupted between the crank pulse of BTDCθ2 (hereinafter abbreviated as “θ2 pulse”) and the cylinder discrimination pulse of BTDCθ5 (hereinafter abbreviated as “θ5 pulse”). It is interrupted between the θ2 pulse and the θ3 pulse. Further, a cylinder discrimination pulse (hereinafter referred to as “θ6 pulse”) of BTDC θ6 of the # 3 cylinder is interrupted between the θ1 pulse and the θ2 pulse of the # 3 cylinder. Accordingly, it is possible to determine that the crank pulse after detecting the θ4 pulse and the θ5 pulse by the cylinder discrimination sensor 22b is the θ3 pulse of the # 1 cylinder, and detect the θ6 pulse by the cylinder discrimination sensor 22b. Thereafter, if the cylinder discrimination pulse is not interrupted between the θ2 pulse and the θ3 pulse detected by the crank angle sensor 22a, it can be discriminated that the θ3 pulse indicates BTDC θ3 of the # 3 cylinder.
[0026]
The timing chart of FIG. 27 shows fuel injection and ignition at the time of starting, the timing chart of FIG. 28 shows fuel injection and ignition at the normal time after starting, and the timing chart of FIG. 29 shows the combustion method from stratified combustion. The correction state of the fuel injection timing when the fuel injection between cylinders overlaps when switching to uniform combustion is shown. The θ1 pulse becomes the reference crank angle for starting the dwell start timing timer at the start, and after the start, becomes the reference crank angle for starting the injection start timing timer. Further, the θ2 pulse becomes the reference crank angle for starting the ignition timing timer after starting. Further, the θ3 pulse becomes a reference point for starting fuel injection and a reference crank angle for starting an ignition timing timer at the time of starting, and becomes a reference crank angle for starting a dwell start timing timer after starting.
[0027]
In a four-cycle four-cylinder engine, the cylinder discriminating crank rotor 21b may be a cam rotor mounted on a camshaft, and the cylinder discriminating sensor 22b may be provided opposite to the cam rotor.
[0028]
Next, the configuration of the fuel system will be described.
[0029]
Reference numeral 23 in FIG. 18 denotes a fuel line. A high-pressure fuel pump 28 is interposed in the middle of the fuel line 23, and a high-pressure electromagnetic pressure regulator 33 is interposed downstream of the high-pressure fuel pump 28. ing. The upstream side of the high-pressure fuel pump 28 of the fuel line 23 constitutes a low-pressure delivery line 23a for sending fuel from the fuel tank 24. The downstream side of the high-pressure fuel pump 28 and the high-pressure electromagnetic pressure regulator 33 constitutes a high-pressure line 23b that boosts fuel from the low-pressure delivery line 23a and supplies it to the high-pressure injector 8, and further, a downstream side of the high-pressure electromagnetic pressure regulator 33 constitutes a low-pressure return line 23c. is doing.
[0030]
The high pressure electromagnetic pressure regulator 33 is a normally open type, and the valve opening is controlled by duty control or current control. In the duty control, the duty ratio is controlled between 0 and 100%. ≧ 80% is fully closed. In the current control, the valve is gradually closed as the control current increases. The high-pressure electromagnetic pressure regulator 33 controls the fuel relief amount of the high-pressure line 23b, thereby holding and controlling the fuel pressure of the high-pressure line 23b, and supplying the fuel amount supplied to the combustion chamber 5 to the high-pressure injector 8. It is designed to measure accurately according to the valve opening time.
[0031]
The low-pressure delivery line 23a and the low-pressure return line 23c are communicated with each other via a fuel bypass passage 23d, and the low-pressure diaphragm pressure regulator 27 for regulating the fuel pressure of the low-pressure delivery line 23a is connected to the fuel bypass passage 23d. Is intervening.
[0032]
In the low-pressure delivery line 23a, the fuel in the fuel tank 24 is sent out by a feed pump 25, and is regulated by the low-pressure diaphragm pressure regulator 27 through the fuel filter 26 to the high-pressure fuel pump 28. Supply.
[0033]
The high-pressure line 23 b constitutes a so-called line pressure maintaining high-pressure injection system, the fuel supplied from the low-pressure delivery line 23 a is pressurized by the high-pressure fuel pump 28, and the pressure is adjusted by the high-pressure electromagnetic pressure regulator 33. The predetermined high-pressure fuel is supplied to the high-pressure injector 8 of each cylinder through a fuel supply path provided with a high-pressure fuel filter 30, an accumulator 31 that buffers pulsation pressure, and a fuel pressure sensor 32 that detects fuel pressure.
[0034]
The high-pressure fuel pump 28 is an engine-driven plunger pump, and check valves are provided at the suction port and the discharge port, respectively, so that fuel from the low-pressure delivery line 23a can pass when the engine is stopped.
[0035]
Next, a control device 40 that performs fuel pressure control, fuel injection control, ignition control, and the like will be described with reference to FIG.
[0036]
This control device 40 is configured around a microcomputer in which a CPU 41, a ROM 42, a RAM 43, a backup RAM 44, an I / O interface 45 and the like are connected to each other via a bus line 46, and supplies a stabilized voltage to each part. Peripheral circuits such as a constant voltage circuit 47 and a drive circuit 48 for driving actuators by a signal from an output port of the I / O interface 45 are incorporated.
[0037]
The constant voltage circuit 47 and the drive circuit 48 are connected in parallel to a battery 50 as a drive power supply via a relay contact of a power supply relay 49, and the relay coil of the power supply relay 49 is connected via an ignition switch 51. The battery 50 is connected. The constant voltage circuit 47 is directly connected to the battery 50, and stabilizes the voltage from the battery 50 when the ignition switch 51 is turned on and the contact of the power relay 49 is closed. The power is supplied to the backup RAM 44 at all times regardless of whether the ignition switch 51 is ON or OFF. A feed pump 25 is connected to the battery 50 through a relay contact of a feed pump relay 54.
[0038]
A battery 50 is connected to the input port of the I / O interface 45 to monitor the battery voltage, as well as the crank angle sensor 22a, the cylinder discrimination sensor 22b, the accelerator opening sensor 16, the water temperature sensor 9, and the fuel. A pressure sensor 32 and a starter switch 53 are connected.
[0039]
On the other hand, to the output port of the I / O interface 45, an igniter 6b for driving an ignition coil 6a provided for each cylinder is connected. Further, via the drive circuit 48, a high-pressure electromagnetic pressure regulator 33 and The relay coil of the feed pump relay 54 is connected, and the high-pressure injectors 8 disposed for the respective cylinders are connected through the injector drive circuits 48 a provided in the drive circuit 48.
[0040]
The ROM 42 stores fixed data such as an engine control program and various tables. The ROM 43 stores data after processing the output signals of the various sensors and switches, and the CPU 41 calculates them. Stores the processed data. The backup RAM 44 stores various learning value maps, control data, and the like, and retains data even when the ignition switch 51 is OFF.
[0041]
The CPU 41 calculates various control amounts such as fuel injection amount and ignition timing at predetermined intervals in accordance with a control program stored in the ROM 42, performs various controls such as fuel injection control and ignition timing control, and the like. When energizing the high-pressure injector 8 of the cylinder and energizing the injectors of other cylinders, by energizing the injector 8 of the fuel injection target cylinder after the energization of the injector is completed, The energization of the injectors between the cylinders is not overlapped, and the voltage drop of the driving power supply to the injectors is prevented to prevent the malfunction of the injector 8 due to the voltage drop.
[0042]
That is, the control device 40 has functions as an energization end determination unit and a fuel injection valve energization control unit, and in addition to general fuel injection control, energization is performed on the injector 8 of the current fuel injection target cylinder. When starting, it is determined whether the injectors of the other cylinders are energized. If the injectors of the other cylinders are energized, the injectors of the current fuel injection target cylinders after energization of the injectors of the other cylinders are completed Is energized to prevent the power supply to the injectors from overlapping between the cylinders and reduce the burden on the power supply for driving the injectors.
[0043]
The control device 40 also has functions as a stratified combustion discrimination means and an ignition timing change means. In order to prevent the power supply to the injectors from overlapping between the cylinders, the current fuel injection target cylinder is energized. When the change is made and stratified combustion is selected, the ignition timing of the cylinder is retarded in response to the change in the start of energization of the injector of the cylinder, and the fuel injection timing and ignition timing required for stratified combustion Always keep the distance between and proper. Further, when energization of the injectors of the current fuel injection target cylinder is started after energization of the injectors of the other cylinders, the energization of the target fuel injection target cylinder after the set time has elapsed after the energization of the injectors of the other cylinders is completed. Energization to the injector is started, and after the voltage of the power source for driving the injector is recovered by the delay time determined by the set time, the energization to the injector is started to improve the fuel metering accuracy by the injector and improve the controllability.
[0044]
Hereinafter, processing related to fuel injection control and ignition timing control by the control device 40 will be described with reference to the flowcharts of FIGS.
[0045]
When the control device 40 is turned on by turning on the ignition switch 51, the system is initialized (the flags and count values in the flowchart are cleared), and then the routines shown in the flowcharts are executed at predetermined timings. Is done.
[0046]
The flowchart shown in FIG. 2 is a cylinder discrimination / engine speed calculation routine that is activated by an interrupt every time a crank pulse is input.
[0047]
After turning on the ignition switch 51, when a crank pulse output from the crank angle sensor 22a is input as the engine rotates, this routine starts. First, in step S1, the crank pulse input this time is any of θ1 to θ3. It is discriminated based on the cylinder discrimination pulse interruption pattern from the cylinder discrimination sensor 22b, and in step S2, the cylinder #i that reaches the next top dead center TDC is discriminated from the cylinder discrimination pulse interruption pattern.
[0048]
That is, as shown in the timing charts of FIGS. Reference example Then, the fuel injection and ignition sequence is set to # 1 → # 4 → # 3 → # 2, and the θ4 pulse is interrupted between the θ1 pulse and the θ2 pulse indicating the top dead center of the # 1 cylinder. , The θ5 pulse is set to be interrupted between the θ2 pulse and the θ3 pulse, and the θ6 pulse is interrupted between the θ1 pulse and the θ2 pulse indicating the top dead center of the # 3 cylinder. Is set to
[0049]
Therefore, if there is no interruption of the cylinder discrimination pulse between at least the previous crank pulse and the previous crank pulse, and the cylinder discrimination pulse is interrupted between the previous crank pulse and the current crank pulse, the current It can be identified that the crank pulse is a θ2 pulse. For cylinder discrimination, if there is an interruption of the cylinder discrimination pulse between the previous and previous crank pulses, and if the cylinder discrimination pulse is also interrupted between the previous and current crank pulses, It can be identified that the pulse is a # 1 cylinder BTDCθ3 pulse. On the other hand, if there is an interruption of the cylinder discrimination pulse between the previous and previous crank pulses, and there is no interruption of the cylinder discrimination pulse between the previous and current crank pulses, the current crank pulse is BTDCθ3 of # 3 cylinder. It can be identified as a pulse. As a result, the cylinder #i that reaches the next top dead center TDC can be determined by the input of the θ3 pulse.
[0050]
Thereafter, in step S3, the pulse input interval time Tθ (see FIG. 28) between the input of the previous crank pulse and the input of the current crank pulse, that is, the time from the previous routine execution to the current routine execution is determined. To detect. Book Reference example As shown in FIG. 20, when the protrusions 21c are formed at equal intervals around the crank redetection crank rotor 21a, the pulse input interval time Tθ can be set in real time.
[0051]
Next, in step S4, the engine speed N is calculated from the pulse input interval time T.theta., Stored as the speed data in a predetermined address of the RAM 43, and the routine is exited. This rotation speed data includes a start determination routine (see FIG. 3), a fuel injection pulse width / injection start timing setting subroutine (see FIGS. 5 to 7), and an ignition timing / energization start time setting routine (see FIGS. 8 and 8). 9).
[0052]
Next, a start determination routine for selecting the engine start time control or the post-start control according to the operating state will be described with reference to the flowchart of FIG. This routine is started by a timer interruption every 10 msec while the ignition switch 51 is turned on and the control device 40 is energized. First, a start determination is performed in steps S11 and S12. Book Reference example In step S11, it is determined that the starter switch 53 is ON, and in step S12, the engine speed N is determined as the start determination speed NST (main Reference example Then, when it is determined that NST = 450 rpm or less, it is determined that the engine is started. The start determination rotational speed NST is appropriately set based on the characteristics of the engine to be mounted.
[0053]
When it is determined in steps S11 and S12 that the engine is being started and the process proceeds to step S13, the start determination flag FST is set and the routine is exited. On the other hand, if the starter switch 53 is OFF in step S11 or if N> NST is determined in step S12, it is determined that the engine is being prepared for start-up or after start-up, and the process branches to step S14 to branch to the start determination flag FST. To exit the routine.
[0054]
Next, a fuel injection pulse width / injection start timing setting routine for setting the fuel injection amount and the fuel injection timing according to the operation state indicated by the start determination flag FST, and an ignition timing for setting the ignition timing and dwell start timing The energization start time setting routine will be described with reference to the flowcharts of FIGS. 4 to 7 and FIGS. Both of these routines are started by the input of the θ2 pulse. When the engine is started, the fuel injection pulse width / injection start timing setting routine is executed in preference to the ignition timing / energization start time setting routine. Are executed in reverse priority order.
[0055]
In both of these routines, the cylinder after the top dead center TDC obtained by cylinder discrimination is set as the current fuel injection / ignition target cylinder #i, the fuel injection pulse width for this cylinder #i, The injection start timing, ignition timing, and energization start time are set for each cylinder. As shown in the timing charts of FIGS. 27 to 29, the injection / ignition order is # 1 → # 4 → # 3 → # 2. In this case, for example, if the cylinder that will reach the top dead center TDC is the # 3 cylinder, the calculation result of the routine started by the interruption of the BTDC θ2 pulse before the top dead center of the # 3 cylinder is the fuel injection and the # 1 cylinder. Applies to ignition.
[0056]
First, a fuel injection pulse width / injection start timing setting routine will be described.
[0057]
As shown in FIG. 4, in step S21 of this routine, it is determined with reference to the value of the start determination flag FST whether the current engine operating state is at the start or after the start. The start determination flag FST is set in the above-described start determination routine (see FIG. 3). When FST = 1, the start determination flag FST is the start time, so that the process proceeds to step S22 and the start time control is executed, while FST = 0. In this case, since it is after the start, the process branches to step S26 to execute the post-start control.
[0058]
First, the startup control will be described. When it is determined that the engine is started at step S21 and the process proceeds to step S22, the injection quantity GFST [g] at startup is set with reference to the table with interpolation calculation based on the cooling water temperature TW detected by the water temperature sensor 9. This table is composed of a series of addresses in the ROM 42, and in each area, the injection amount for ensuring the starting performance in the cold state is preliminarily obtained from experiments and stored, and as shown in the steps, The lower the coolant temperature TW, the higher the starting injection amount GFST is set.
[0059]
Next, a table in which the fuel pressure coefficient KS and the invalid injection time TS [msec] are stored as data in the ROM 42 based on the fuel pressure PS [kpa] in the high pressure line 23b detected by the fuel pressure sensor 32 in step S23. Is set with reference to interpolation calculation. As shown in this step, in the table, the fuel pressure coefficient KS and the invalid injection time TS are obtained by experiment or design in advance using the fuel pressure PS as a grid. The fuel pressure coefficient KS is an injection characteristic of the high-pressure injector 8 that changes according to the fuel pressure PS. The start-up injection amount GFST is corrected according to the fuel pressure PS, and the start-up injection amount GFST [g] is timed. Convert. The invalid injection time TS compensates for the operation delay of the high-pressure injector 8 that varies with the fuel pressure PS.
[0060]
Next, when the routine proceeds to step S24, the starting injection amount GFST [g] is multiplied by the fuel pressure coefficient KS to convert the time, and the invalid injection time TS is added to the value to obtain the fuel injection time at starting. The fuel injection pulse width Ti that determines the fuel injection amount is calculated by the above, and the routine proceeds to step S25, where the fuel injection pulse width Ti is set in the fuel injection timer of the current injection / ignition target cylinder #i and the routine is exited. The start-up fuel injection timer set in step S25 is started by a routine executed for each θ3 pulse input shown in the flowchart of FIG. 12 (details will be described later).
[0061]
On the other hand, when the start of the engine is completed, the start determination flag FST is cleared in step S14 of the start determination routine shown in the flowchart of FIG. Then, in the fuel injection pulse width / injection start timing setting routine, the process branches from step S21 to step S26, and the control proceeds to post-startup control. As described above, when the engine shifts from the starting state to the after starting state, the priority order of the routine is reversed, and before this fuel injection pulse width / injection start timing setting routine, an ignition timing / energization start time setting described later is set. The routine is executed.
[0062]
In step S26, a fuel injection pulse width / injection start timing setting subroutine during normal control is executed.
[0063]
This fuel injection pulse width / injection start timing setting subroutine is executed according to the flowcharts shown in FIGS.
[0064]
First, in step S31, based on the accelerator opening (= throttle opening) α detected by the accelerator opening sensor 16 and the engine speed N, the table shown in the step is referred to with interpolation calculation, and the intake air A basic air supply ratio L0 corresponding to the amount is set. In each area of this table, an optimal basic air supply ratio L0 is previously obtained from experiments and stored in accordance with the accelerator opening α and the engine speed N.
[0065]
Next, the process proceeds to step S32, and after starting, the fuel pressure coefficient KS and the invalid injection time TS are set based on the fuel pressure PS in the high pressure line 23b detected by the fuel pressure sensor 32. The fuel pressure coefficient KS and the invalid injection time TS are set by referring to the table shown in step S23 (see FIG. 4) with interpolation calculation.
[0066]
Thereafter, a uniform / stratified combustion switching determination value LS2 is set based on the engine speed N in step S33. The combustion switching determination value LS2 is tabulated based on the characteristics shown in step S33, and this table is set with reference to interpolation calculation.
[0067]
This uniform / stratified combustion switching determination value LS2 is a reference value used as a reference when switching the combustion mode according to the engine load. Reference example Then, the basic air supply ratio L0 is taken in as the engine load, and the combustion mode is switched between the uniform combustion method and the stratified combustion method. That is, when the engine is in high load operation (L0> LS2), the uniform combustion method is adopted, and in the middle and low load operation (L0 ≦ LS2), the stratified combustion method is adopted. Each combustion method is switched by changing the fuel injection timing and the ignition timing.
[0068]
Where the book Reference example Each combustion method employed by will be described.
[0069]
Uniform combustion is a combustion system in which fuel is injected at an early stage, ignited after being uniformly mixed in a cylinder, and is suitable for high-load operation because of its high air utilization rate. This uniform combustion mixture formation and combustion process will be described based on the fuel injection / ignition timing diagram in FIG. 23 and in accordance with the uniform combustion stroke diagram in FIG.
[0070]
First, the injection start timing IJST shown in FIG. 23 is set to an early time after the exhaust rotary valve 17 is closed (FIG. 24A). Here, the earlier the injection start timing, the better. However, if fuel injection is started earlier than the valve closing timing of the exhaust port 3b by the exhaust rotary valve 17, there is a problem that fuel blows out into the exhaust passage through the exhaust port 3b. The injection start timing is set after the exhaust port 3b is closed. Then, after the injection is finished ((b) in the figure), the mixture is compressed and mixed by raising the piston 4 (FIG. (C)), and ignited at a predetermined ignition advance angle ((d) in the figure). Then, the flame propagates through the combustion chamber 5 and burns ((e) in the figure).
[0071]
On the other hand, stratified combustion is a combustion system in which fuel injection ends just before ignition and sparks are ignited at the rear end of the fuel spray. Since only the air around the fuel is used, it is stable with an extremely small amount of fuel compared to the amount of charged air Suitable for low and medium load operation. The combustion process by the stratified combustion will be described according to the stratified combustion stroke diagram of FIG. 26 based on the fuel injection / ignition timing diagram of FIG. First, the injection start timing IJST shown in FIG. 25 is set so that the fuel injection ends just before ignition (FIG. 26A), and the fuel being injected is mixed in the vicinity of the spark plug 7 while taking in air. At the same time, a lean air-fuel mixture is formed in a layered form around the gas (FIG. 2B). When the rich mixture after the injection is ignited ((c) in the figure), the flame ignited in the rich mixture propagates to the surrounding lean mixture and burns the lean mixture (see the figure). (D)).
[0072]
In step S33, after setting the uniform / stratified combustion switching determination value LS2 in order to determine the combustion method to be adapted to the current operating state, when the process proceeds to step S34, the basic air supply ratio L0 (= engine load) and The uniform / stratified combustion switching determination value LS2 is compared. For example, at the time of low load operation such as idling or medium load operation such as steady running, it is determined in this step S34 that L0 ≦ LS2 and the process proceeds to step S35. On the other hand, if it is determined that the high load operation is L0> LS2, the process branches to step S41 in FIG.
[0073]
First, a control routine during low and medium load operation will be described. When it is determined that the operation is low and medium load and the process proceeds from step S34 to step S35, the combustion method determination flag F1 is cleared. In the combustion method determination flag F1, F1 = 0 represents a stratified combustion method, and F1 = 1 represents a uniform combustion method.
[0074]
When the combustion system after engine startup is set to the stratified combustion system with F1 = 0 in step S35, the process proceeds to step S36, and the table is interpolated based on the basic air supply ratio L0 and the engine speed N. The fuel injection amount GF [g] is set with reference to the calculation. Thereafter, in step S37, the injection end timing IJET (FIG. 28) for determining how many degrees CA of fuel injection is terminated before ignition by referring to the table with interpolation calculation based on the basic air supply ratio L0 and the engine speed N (FIG. 28). (B) is set. In order to obtain optimum combustion by stratified combustion, a rich air-fuel mixture must be formed around the spark plug 7 at the time of ignition (see FIGS. 26B and 26C), and therefore the time between the end of injection and ignition You need to manage the interval. Book Reference example Then, the injection end timing IJET at the time of stratified combustion is experimentally obtained in advance and stored as a table using the basic air supply ratio L0 and the engine speed N as parameters. The unit of the injection end timing IJET is before ignition [msec].
[0075]
Next, when the process proceeds from step S37 to step S38, the injection amount GF [g] set in step S36 is multiplied by the fuel pressure coefficient KS to convert the time, and the invalid injection time TS is added to the value. Then, the fuel injection pulse width Ti is calculated (Ti ← KS × GF + Ts).
[0076]
In step S39, the injection start timing IJST at the time of stratified combustion is calculated from the following equation.
[0077]
IJST ← TθM1- (TADV + IJET + Ti)
Here, TθM1 is the time from reaching the top dead center TDC of the injection / ignition target cylinder #i from the crank pulse input serving as a reference when setting the injection start timing. Reference example Then, as shown in the timing chart of FIG. 28, the θ1 pulse input is set as the reference crank angle. The TθM1 when the θ1 pulse input is a reference crank angle is
Calculated by TθM1 = 2.5 × Tθ. TADV is an ignition advance time conversion value, which is calculated by the ignition timing / energization start time setting routine of FIGS.
[0078]
Thereafter, the process proceeds to step S40, the injection start timing IJST calculated in step S39 is set in the injection start timing timer of the current fuel injection target cylinder #i, and the process returns to step S25 (see FIG. 4). The fuel injection pulse width Ti calculated in step S38 is set in the fuel injection timer for the injection target cylinder #i, and the routine is exited.
[0079]
On the other hand, at the time of transition such as acceleration operation or at high speed operation, in step S34, the basic air supply ratio L0 set in step S31 is compared with the uniform / stratified combustion switching determination value LS2 set in step S33. As a result, at the time of high load operation with L0> LS2, the routine branches to step S41, the combustion mode discrimination flag F1 is set to indicate the uniform combustion mode, and the basic air supply ratio L0, engine speed N and The fuel injection amount GF [g] for uniform combustion is set with reference to the table with interpolation calculation based on the above, and in step S43, the fuel injection amount GF is multiplied by the fuel pressure coefficient KS set in step S32. Then, the invalid injection time TS is added to the value to calculate the fuel injection pulse width Ti during uniform combustion (Ti ← KS × GF + Ts).
[0080]
Next, in step S44, based on the basic air supply ratio L0 and the engine speed N, the table is referenced with interpolation calculation to determine the injection start timing for the current injection / ignition target cylinder #i during uniform combustion. The injection start angle IJsa [° CA] before the point is set. Book Reference example The injection start angle IJsa is set based on the top dead center TDC of the current injection / ignition target cylinder #i (see FIG. 28C). In uniform combustion, it is desirable to terminate the fuel injection as early as possible and mix it with fresh air sufficiently. However, if the fuel injection is started earlier than the time when the exhaust port 3b is closed, fuel blow-out occurs. This fuel injection start timing is managed by the crank angle, and fuel injection is started early after the exhaust port 3b is closed.
[0081]
Next, in step S45, the injection start timing IJST corresponding to the injection start angle IJsa [° CA] is calculated from the following equation.
[0082]
IJST ← TθM2− (Tθ / θs) × IJsa
TθM2 is the time from the crank pulse input serving as a reference when setting the injection start timing to the top dead center TDC of the current injection / ignition target cylinder #i, as shown in the timing chart of FIG. Book Reference example In, the θ1 pulse input one cylinder before is set as the reference crank angle,
Calculated by TθM2 = 5.5 × Tθ. Θs is the angle between crank pulses. Reference example Then, it is 30 ° CA. Therefore,
By using (Tθ / θs) × IJsa, the injection start angle is time-converted from the time per 1 ° CA rotation, and this value is subtracted from the above TθM2, so that the θ1 pulse input one cylinder before is the reference crank angle. A start timing IJST is calculated (see FIG. 28C).
[0083]
Thereafter, the process returns to step S40, and the injection start timing IJST calculated in step S45 is set in the injection start timing timer of the current injection / ignition target cylinder #i. Then, the process returns to step S25 (see FIG. 4), the fuel injection pulse width Ti calculated in step S43 is set in the fuel injection timer of the current injection / ignition target cylinder #i, and the routine is exited.
[0084]
Next, the ignition timing / energization start time setting routine will be described based on the flowcharts shown in FIGS. As described above, this routine is executed after the above-described fuel injection pulse width / injection start timing setting routine at the time of engine start, and after the engine is started, this fuel injection pulse width / injection start timing setting routine has priority. Executed.
[0085]
First, in step S51, it is determined with reference to the value of the start determination flag FST whether the current operating state is at the start or after the start. This start determination flag FST is set in the above-described start determination routine of FIG. 3, and when FST = 1, it is an engine start time, so the process proceeds to step S52 and the start time control is executed, while FST = 0. In this case, since it is after starting, the process branches to step S57 to perform control after starting.
[0086]
First, the starting control will be described, and then the post-starting control will be described.
[0087]
In step S51, when it is determined that FST = 1 is started and the process proceeds to step S52, the energization time DWL [msec] is set based on the battery voltage VB with reference to the table with interpolation calculation. In the series of addresses in this table, as shown in the step, the characteristics in which the energization time DWL [msec] is set shorter as the battery voltage VB is higher are stored as data.
[0088]
Next, the process proceeds to step S53, and the ignition timing IGt is obtained from the following equation.
[0089]
IGt ← Ti + IGST
IGST: Pre-set time from the end of injection to ignition [msec] (stored as ROM data) This ignition timing IGt determines how many milliseconds after ignition of a specific reference crank pulse, Book Reference example Then, as shown in FIG. 27 (b), the fuel injection pulse width Ti at the time of starting is set so as to start injection with the θ3 pulse as a reference crank angle, and after the fuel injection with this fuel injection pulse width Ti is completed. It is set to ignite after the set time IGST has elapsed.
[0090]
Thereafter, the dwell start timing DWLST is calculated from the following equation in step S54.
[0091]
DWLST ← (TθM3 + IGt) −DWL
TθM3: Time from crank pulse input as a reference for setting the dwell start timing to crank pulse input as the ignition timing setting reference As shown in the timing chart of FIG. Reference example The reference crank angle at the start of the dwell at the start is the θ1 pulse, and the reference crank angle at the time of setting the ignition timing is the θ3 pulse. Therefore, TθM3 is
It can be calculated by TθM3 = 2 × Tθ.
[0092]
Thereafter, in step S55, the ignition timing IGT is set in the ignition timing timer of the current injection / ignition target cylinder #i. In step S56, the dwell start timing DWLST is set in the dwell start timing timer, and the routine is exited.
[0093]
The dwell start timing timer for the injection / ignition target cylinder #i set in step S56 at the start is started with the BTDCθ1 pulse before top dead center as the reference crank angle, while the ignition timing set in step S55. The timer is started with the BTDC θ3 pulse before top dead center as a reference crank angle (details will be described later).
[0094]
On the other hand, when the start of the engine is completed, since the start determination flag FST is cleared in step S14 of the start determination routine shown in FIG. 3, the ignition timing / energization start time setting routine starts from step S51. The process branches to step S57 shown in FIG. As described above, when the engine shifts from the start state to after the start, the priority order of the routine is reversed, and this ignition timing / energization start time setting routine is the same as the fuel injection pulse width / injection start timing setting routine described above. Executed before.
[0095]
In step S57, the latest basic air supply ratio L0 and engine speed N are read out. Next, in step S58, the book Reference example In order to set the advance value ADV [° CA] that determines the ignition timing according to each combustion method employed in step 1, first, the currently selected combustion method is determined with reference to the value of the combustion method determination flag F1. This combustion method discrimination flag F1 is set according to the engine load in the above-described fuel injection pulse width / injection start timing setting routine, F1 = 0 represents the stratified combustion method, and F1 = 1 represents the uniform combustion method. Represents.
[0096]
When it is determined in step S58 that the current combustion method is stratified combustion with F1 = 0, the process proceeds to step S59, and the ignition charge value ADV [° CA] at the time of stratified combustion is read out in step S57. Based on the ratio L0 and the engine speed N, the table is set with reference to interpolation calculation. The ignition advance value ADV determines how many degrees CA before the top dead center is ignited. The ignition advance value ADV is stored in the ROM 42 as a table using the basic air supply ratio L0 and the engine speed N as parameters. Stores the ignition advance value ADV adapted to the stratified combustion for each region divided by the basic air supply ratio L0 and the engine speed N determined in advance through experiments or the like. In addition to the table for storing the ignition advance value ADV at the time of stratified combustion, the ignition advance value ADV at the time of uniform combustion, which will be described later, is previously obtained from experiments and stored in a series of addresses in the ROM 42.
[0097]
Thereafter, in step S60, the energization time DWL is set based on the battery voltage VB by referring to the table with interpolation calculation in the same manner as described above, and in step S61, from the time per 1 [° CA] rotation, An ignition advance time conversion value TADV for converting the ignition advance value ADV [° CA] during stratified combustion set in S59 into time is calculated based on the following equation.
[0098]
TADV ← (Tθ / θs) x ADV
Tθ: Latest crank pulse input interval time
θs: Angle between crank pulses (this Reference example In step S62, the ignition timing IGt is calculated from the following equation based on the ignition advance time converted value TADV.
[0099]
IGt ← TθM4-TADV
The above TθM4 is the time from the crank pulse input, which is a reference for setting the ignition timing [msec], to the top dead center TDC of the current injection / ignition target cylinder #i. Reference example In FIG. 28, the BTDCθ2 pulse before top dead center of the injection / ignition target cylinder #i is used as a reference crank pulse, and is calculated by TθM4 = 1.5 × Tθ as shown in the timing chart of FIG.
[0100]
Next, in step S63, a dwell start timing DWLST corresponding to the ignition timing is calculated based on the following equation.
[0101]
DWLST ← TθM5− (DWL + TADV)
Here, TθM5 is the time from the crank pulse input as a reference for setting the dwell start timing to the top dead center TDC of the current injection / ignition target cylinder #i. Reference example Then, the BTDC θ3 pulse before the top dead center of the cylinder before one cylinder is used as a reference crank pulse, and as shown in the timing chart of FIG.
TθM5 = 3.5 × Tθ is calculated.
[0102]
Then, the process returns to step S55, the ignition timing IGT is set in the ignition timing timer of the current injection / ignition target cylinder #i, the dwell start timing DWLST is set in the dwell start timing timer in step S56, and the routine is exited. .
[0103]
On the other hand, if it is determined in step S58 that the current combustion method is uniform combustion with F1 = 1, the process proceeds to step S64, and the ignition advance value ADV [° CA] at the time of uniform combustion is read in step S57. The table is set with reference to interpolation calculation based on the basic air supply ratio L0 and the engine speed N. Returning to step S60, the energization time DWL is set by referring to the table based on the battery voltage VB. In step S61, the ignition advance value ADV [° CA] at the time of uniform combustion set in step S64 is set as the time. The ignition advance time conversion value TADV to be converted is calculated (TADV ← (Tθ / θs) + ADV), and the ignition timing IGt is calculated based on the ignition advance time conversion value TADV in step S62 (IGt ← TθM4−TADV In step S63, the dwell start timing DWLST is calculated (DWLST ← TθM5− (DWL + TADV)). Returning to step S55, the ignition timing IGt for uniform combustion is set in the ignition timing timer of the current injection / ignition target cylinder #i. In step S56, the dwell start timing DWLST is set in the dwell start timing timer. Exit the routine.
[0104]
Next, routines for starting the timers set in the routines will be described with reference to the flowcharts of FIGS.
[0105]
First, when the θ1 pulse is input at the time of start, the start-time dwell start timing timer / post-start injection start timing timer start routine shown in the flowchart of FIG. 10 is started.
[0106]
In step S71, the value of the start determination flag FST is referred to and it is determined whether or not the current operating state is a start time. At the time of engine start, since FST = 1, the routine proceeds to step S72, where the dwell start timing timer for the current injection / ignition target cylinder #i in which the dwell start timing DWLST is set is started, and the routine is exited. As a result, the time measurement of the dwell start timing DWLST [msec] set in the dwell start timing timer is started (see FIG. 27B), and when the time measurement ends, the dwell start routine shown in the flowchart of FIG. 15 is interrupted. In step S141, a dwell for the ignition coil 6a of the current injection / ignition target cylinder #i is started via the igniter 6b and the routine is exited.
[0107]
Next, when the θ2 pulse is input, a post-startup ignition timing timer start routine shown in the flowchart of FIG. 11 is started, and in step S101, the value of the start determination flag FST is referred to, and the current operating state is FST = 1. In the case of starting, the routine is exited as it is.
[0108]
Subsequently, when the θ3 pulse is input, the start-time injection start timer, the ignition timing timer, and the post-start dwell start timing timer start routine shown in the flowchart of FIG. 12 are started. In step S111, the value of the start determination flag FST is started. Referring to FIG. 4, when the current operation state is FST = 1, the process proceeds to step S112, and the fuel injection timer for the current injection / ignition target cylinder #i at the start is started. Then, the measurement of the fuel injection pulse width Ti set in the fuel injection timer is started (see FIG. 27B), and during that time, an injection signal is output to the high pressure injector 8 of the corresponding cylinder #i. In this way, a predetermined amount of fuel is directly injected into the cylinder.
[0109]
Next, in step S113, the ignition timing timer for the cylinder #i is started, and the routine is exited. Then, the timing of the ignition timing IGt [msec] set in the ignition timing timer is started (see FIG. 27B), and when the timing ends, the ignition control routine shown in the flowchart of FIG. 16 is interrupted and activated. The
[0110]
Then, in step S151 of this ignition control routine, the value of the start determination flag FST is referred to. When FST = 1 is started, the process proceeds to step S152, and the ignition / ignition target cylinder #i via the igniter 6b is applied to the ignition coil 6a. Cut the dwell and exit the routine. As a result, combustion is started by spark ignition of the spark plug 7, and the engine is started.
[0111]
When the θ1 pulse is input after the engine is started and the routine shown in the flowchart of FIG. 10 is started, in step S71, it is determined that FST = 0 has been started, and the process branches to step S73. Is determined with reference to the value of the combustion method determination flag F1.
[0112]
Book Reference example As shown in the timing chart of FIG. 28 (b), in the stratified combustion, the injection start timing timer is set to start with the θ1 pulse input of BTDC before the top dead center of the injection / ignition target cylinder #i. On the other hand, as shown in FIG. 6C, in the uniform combustion, the injection start timing timer is started by inputting the θ1 pulse of BTDC before the top dead center of the cylinder immediately before the current injection / ignition target cylinder #i. Is set to
[0113]
Therefore, in order to determine the injection / ignition target cylinder #i for starting the injection start timing timer, in step S73, the currently set combustion method is determined.
[0114]
When stratified combustion with F1 = 0 is selected in step S73, the process proceeds to step S74, and the cylinder that will reach the top dead center TDC, that is, the current cylinder is set as the current injection / ignition target cylinder #i. In step S75, the injection start timing timer for the injection / ignition target cylinder #i is started and the routine is exited.
[0115]
On the other hand, when F1 = 1 uniform combustion is selected in step S73, the process branches to step S76, and the cylinder immediately after the top dead center is set as the current injection / ignition target cylinder #i. In step S75, the injection start timing timer for the cylinder #i is started, and the routine is exited.
[0116]
That is, as shown in the timing chart of FIG. 28, for example, when the injection / ignition target cylinder #i is the # 1 cylinder and the stratified combustion is selected, as shown in FIG. The start timing timer is started by BTDCθ1 pulse input before top dead center of the # 1 cylinder, and at the time of uniform combustion, as shown in FIG. 5C, BTDCθ1 before top dead center of the previous # 2 cylinder. Start with pulse input.
[0117]
When the measurement of the injection start timing IJST [msec] set in the injection start timing timer is completed, the injection start timing routine shown in the flowchart of FIG. 13 is interrupted and activated. In this routine, the fuel injection period of each cylinder, that is, the injection start timing is controlled so that the energization periods of the injectors 8 of each cylinder do not overlap.
[0118]
First, in step S121, whether or not fuel injection is being performed in another cylinder is determined based on whether or not the fuel injection timer of the other cylinder is timing. When the fuel injection timer of one of the other cylinders is counting, when the fuel injection of the current injection / ignition target cylinder #i is started, energization to the plurality of injectors 8 is overlapped, and the injectors 8 are connected via the injector drive circuit 48a. Since the load of the power source for driving the valve to open increases, the process proceeds to step S122, and after the fuel injection of the other cylinders is completed, that is, after the energization of the injectors of the other cylinders is completed, the current injection is performed. Delay the fuel injection start timing of the cylinder #i so as to start energization of the injector of the ignition target cylinder #i.
[0119]
In step S122, the time measured value TMan of the fuel injection timer of the other cylinder during the time measurement is read out. Where the book Reference example , A countdown type fuel injection timer is employed, and the time measured value TMan represents the time until the end of fuel injection in the other cylinder, that is, the end of energization of the injector 8 in the other cylinder.
[0120]
Then, in step S123, the cylinder injection start delay time TMt # i for delaying the fuel injection start timing for the current injection / ignition target cylinder #i by adding the set time TMs to the time measured value TMan is set. The set time TMs is a time for applying the voltage recovery of the power source for driving the injector. After the energization to the high pressure injector 8 of the other cylinder is completed, the energization to the injector 8 of the cylinder #i is started after the set time elapses. By doing so, after the voltage of the power source for driving the injector is recovered, energization to the injector 8 of the cylinder #i is started, and the fuel metering accuracy by the injector 8 is improved. Note that the set time TMs is not necessarily required, and the measured time value TMan may be used as it is as the injection start delay time TMt # i. Also book Reference example Uses a countdown type fuel injection timer, so the timer count value TMan is used as the time until the fuel injection of the other cylinders ends, but the fuel injection timer counts up from 0 to Ti. In the case of the equation, a value obtained by subtracting the time measured value of the timer from the fuel injection pulse width of the other cylinder during fuel injection is used as the time until the end of the other cylinder injection.
[0121]
Next, in step S124, the cylinder injection start delay time TMt # i is reset to the injection start timing timer of the current injection / ignition target cylinder #i, and this time when stratified combustion is selected in step S125. The ignition timing change flag FD # i is set in order to delay the ignition timing of the cylinder #i in response to the delay of the fuel injection start timing of the cylinder #i to be injected / ignited, and the injection of the cylinder #i is performed in step S126. Restart the start timing timer and exit the routine.
[0122]
When the counting of the injection start delay time TMt # i [msec] set in the injection start timing timer is completed, the injection start routine shown in the flowchart of FIG. 14 is interrupted and started, and in step S131, the current injection / ignition is performed. The fuel injection timer for the target cylinder #i is started and the routine is exited.
[0123]
As a result, the fuel injection pulse width (set in the fuel injection timer of the cylinder #i after the injection start delay time TMt # i has elapsed for the high-pressure injector 8 of the current injection / ignition target cylinder #i. Time) Ti is started to be measured, and until the time value TMan of the fuel injection timer of the cylinder #i is changed from Ti to 0, the injector drive circuit 55a is supplied to the high-pressure injector 8 of the current injection / ignition target cylinder #i. From which an injection signal is output and fuel is injected.
[0124]
That is, as shown in the timing chart of FIG. 29, when the current injection / ignition target cylinder #i is the # 1 cylinder, when the fuel injection to the # 1 cylinder is started, the previous cylinder # 2 If the fuel injection of the cylinder has not yet ended, the fuel injection of the # 1 cylinder is performed after the injection start delay time TMt # i obtained by adding the time TMan until the end of the injection of the # 2 cylinder and the set value TMs at that time. Since this is started, energization in each injector 8 through each injector drive circuit 48a does not overlap, and therefore the burden on the power source for driving this injector is reduced. By the way, as shown in FIG. 29, when the fuel injection overlaps between the cylinders, the fuel injection start timing of the cylinder to be injected later is slightly behind the normal injection timing, but the fuel injection of each cylinder overlaps. As shown in the figure, the period of time is generated when the combustion system is switched from stratified combustion to uniform combustion, for example. In this uniform combustion, even if the injection start timing is slightly delayed, there is a sufficient time until ignition so that the combustion is not greatly affected.
[0125]
At this time, in the ignition timing control described later, the ignition timing is ignited at the normal ignition timing regardless of the change in the fuel injection start timing. That is, as shown in FIG. 29, uniform combustion has a sufficient margin from the start of injection to ignition, and if the ignition timing is shifted, the combustion state deteriorates.
[0126]
On the other hand, at the time of stratified combustion, as described above, it is necessary to form a rich air-fuel mixture around the spark plug 7 at the time of ignition, and it is necessary to manage the time interval between the end of fuel injection and ignition.
[0127]
Accordingly, when the fuel injection timing of the current injection / ignition target cylinder #i is delayed by the injection start delay time TMt # i in order to avoid the overlapping of the energization of the injector 8 between the cylinders in the stratified combustion, In response to this, the ignition timing of the cylinder #i must be delayed, that is, retarded. For this reason, when the fuel injection timing of the cylinder #i is delayed, the ignition timing change flag FD # i for the cylinder #i is set in step S125 of the fuel injection start timing routine (FIG. 13). As will be described later, in the ignition control routine shown in FIG. 16, the ignition timing of the cylinder #i is retarded corresponding to the cylinder injection start delay time TMt # i.
[0128]
Book Reference example Then, the calculation of the fuel system (fuel injection timing, fuel injection amount) and the calculation of the ignition system (dwell start timing, ignition timing) for the cylinder to be injected / ignited #i are performed for the cylinders two preceding cylinders as described above. This is performed in a routine that is activated when an BTDCθ2 pulse before top dead center is input.
[0129]
On the other hand, in step S121 of the injection start timing routine of FIG. 13, if the fuel injection timers of all other cylinders are not driven, there is no cylinder that is injecting fuel, and the injector for the current injection / ignition target cylinder #i It is determined that there is no overload of the injector driving power source even if the current is applied to the cylinder 8 without energizing the injectors of other cylinders, and the process proceeds to step S127. In steps S127 and S128, the ignition timing of the cylinder #i is determined. The change flag FD # i and the injection start delay time TMt # i are cleared, the fuel injection timer for the current injection / ignition target cylinder #i is started in step S129, and the routine is exited.
[0130]
Then, while the fuel injection pulse width Ti set in the fuel injection timer is being measured for the high pressure injector 8 of the current injection / ignition target cylinder #i, the injection signal is passed through the injector drive circuit 48a. Is output, and fuel is injected into the cylinder #i by opening the high-pressure injector 8.
[0131]
Accordingly, when the fuel injection timing between the cylinders does not overlap and the injector energization between the cylinders does not overlap, the fuel injection is performed at the initial injection start timing for the current injection / ignition target cylinder #i.
[0132]
In addition, as shown in the timing chart of FIG. 28, the ignition timing control after the engine start is performed by the BTDC θ3 pulse input before the top dead center of the cylinder immediately before the current injection / ignition target cylinder #i, and the dwell start timing DWLST. First, a routine that is activated by an interrupt by the θ3 pulse input shown in the flowchart of FIG. 12 will be described.
[0133]
When the θ3 pulse is input and the routine shown in the flowchart of FIG. 12 is started, first, in step S111, it is determined that the current operation state is after the start of FST = 0, and the process branches to step S114. The dwell start timing timer of the injection / ignition target cylinder #i is started.
[0134]
Then, the time measurement of the dwell start timing DWLST set in the dwell start timing timer is started, and when this time measurement ends, the dwell start routine shown in the flowchart of FIG. 15 is interrupted and activated. In step S141 of this dwell start routine, the dwell of the current injection / ignition target cylinder #i is set and the routine is exited. As a result, a dwell for the ignition coil 6a of the current injection / ignition target cylinder #i is started via the igniter 6b.
[0135]
The dwell of the injection / ignition target cylinder #i set in the dwell start routine is cut when the ignition control routine shown in the flowchart of FIG. 16 or the ignition routine shown in FIG. Will be described later).
[0136]
Thereafter, when the θ2 pulse is input and the ignition timing timer start routine shown in FIG. 11 is interrupted and activated, in step S101, the value of the start determination flag FST is referred to and the current operating state is after the start of FST = 0. In this case, the routine branches to step S102, where the ignition timing timer for the current injection / ignition target cylinder #i is started and the routine is exited.
[0137]
Then, the ignition timing IGt [msec] set in the ignition timing timer is counted, and when the timing ends, the ignition control routine shown in the flowchart of FIG. 16 is interrupted and activated. Then, in step S151, the value of the start determination flag FST is referred to. After the engine start with FST = 0, the process branches to step S153, and the ignition timing of the cylinder #i is delayed in steps S153 and S154. It is determined whether or not to retard in response to.
[0138]
That is, when the fuel injection timing of the current injection / ignition target cylinder #i is delayed in order to avoid the overlapping of the energization of the injector 8 between the cylinders in the stratified combustion, the ignition timing of the cylinder #i corresponding to this is delayed. Must be delayed, i.e. retarded. Therefore, in step S153, referring to the value of the combustion method determination flag F1, it is determined whether the current combustion method is selected as stratified combustion or uniform combustion, and stratified combustion with F1 = 0 is selected. When it is determined that the ignition timing change flag FD # i for the cylinder #i is set, the process proceeds to step S154.
[0139]
When the stratified charge combustion of F1 = 0 is selected and the ignition timing change flag FD # i of the cylinder #i is FD # i = 1, the cylinder #i is ignited with the delay of the fuel injection timing. When the timing delay is instructed, the process proceeds to step S155, and the injection start delay time TMt # i of the cylinder #i is read. In step S156, the injection start delay time TMt # i is determined as the current injection / ignition target. The ignition timing timer for cylinder #i is reset to restart the ignition timing timer, and the routine is exited.
[0140]
When the timing of the delay time TMt # i [msec] set in the ignition timing timer is completed, the ignition routine shown in the flowchart of FIG. 17 is interrupted and started, and in step S161, the current injection / ignition target cylinder #i Cut the dwell against and exit the routine.
[0141]
As a result, at the time of stratified combustion, when the fuel injection timing is delayed for the cylinder #i, the ignition timing is delayed correspondingly, and after the delay time TMt # i has elapsed with respect to the initially set ignition timing IGt The dwell for the ignition coil 6a of the cylinder #i is cut through the igniter 6b, and the cylinder #i is ignited.
[0142]
Therefore, during stratified combustion, when the fuel injection timing of the cylinder #i is delayed by the injection start delay time TMt # i in order to avoid duplication of energization of the injector 8 between the cylinders, Since the ignition timing of cylinder #i is delayed, the time interval between the end of fuel injection and ignition is always properly managed during stratified combustion when a rich mixture must be formed around the spark plug 7 during ignition. Will be.
[0143]
On the other hand, in the ignition control routine of FIG. 16 described above, when F1 = 1 in step S153 and uniform combustion is selected, it is not necessary to retard the ignition timing regardless of whether the fuel injection timing is delayed, Further, even in the case of stratified combustion with F1 = 0, when FD # i = 0 in step S154 and the fuel injection timing of the cylinder #i is not delayed and the retard of the ignition timing is not instructed, Proceeding to step S152, the dwell for the cylinder #i is cut and the routine is exited.
[0144]
Therefore, at this time, the ignition / ignition target cylinder #i is ignited at the initial ignition timing IGt.
[0145]
Book like this Reference example According to the present invention, when energization is started for the high pressure injector 8 of the current injection / ignition target cylinder #i and there is a cylinder that is energized for the injector 8 in another cylinder, the energization of this cylinder is terminated. After that, since energization is started for the injector 8 of the current injection / ignition target cylinder #i, the burden on the power source for driving the injector is reduced and the voltage drop is prevented. As a result, a malfunction such as insufficient lift of the needle of the high-pressure injector 8 does not occur, and an appropriate fuel amount can always be supplied.
[0146]
In addition, when the fuel injection timing of the current injection / ignition target cylinder #i is delayed to avoid duplication of injector energization between the cylinders, this corresponds to the delay of the fuel injection timing when stratified combustion is selected. Since the ignition timing of the cylinder #i is delayed, the time interval between the end of fuel injection and ignition is always properly managed during stratified combustion, and a rich mixture is formed around the spark plug 7 during ignition. In addition, it is possible to reliably prevent deterioration of ignitability associated with the change of the fuel injection timing.
[0147]
Further, when the fuel injection timing of the current injection / ignition target cylinder #i is delayed in order to avoid duplication of injector energization between the cylinders, the set time TMs is further increased after the energization to the high pressure injector 8 of the other cylinders is completed. Since energization to the injector 8 of the cylinder #i is started after elapse of time, energization to the injector 8 of the cylinder #i is started after the voltage recovery of the injector driving power supply, and the fuel metering accuracy by the injector 8 can be improved. It becomes possible.
[0148]
Next, based on FIGS. Embodiments of the present invention Will be explained.
[0149]
Above Reference example In the present embodiment, the energization of the high-pressure injectors 8 between the cylinders is controlled so as not to overlap. However, in the present embodiment, only the initial pull-up energization periods for the high-pressure injectors 8 of the respective cylinders do not overlap. To control.
[0150]
The configuration of the engine and the configuration of the control system are as described above. Reference example Is the same.
[0151]
Here, the control device 40 includes: Reference example In place of the energization end determination means in FIG. 6, the function is as a pull-up current end determination means, and when energization is started for the injector of the current fuel injection target cylinder, the pull-up is performed for the injectors of other cylinders. It is determined whether there is a current-carrying cylinder, and when the pull-up current is being supplied to the injectors of the other cylinders, the injector of the current fuel injection target cylinder is turned on after the completion of the pull-up current supply to the injectors of the other cylinders. By starting energization, overlap of injector energization between the cylinders is avoided only during a pull-up current energization period that requires a large current, and delay in fuel injection timing is minimized.
[0152]
In particular, Reference example On the other hand, the injection start routine shown in FIG. 14 is eliminated, and the routine shown in FIGS. 32 and 33 is used to set or clear the pull-up flag FPUL indicating the energization state of the pull-up current according to the pull-up current energization state. In addition, an injection start timing routine shown in FIG. 34 is adopted instead of the injection start timing routine shown in FIG. 13, and energization to the injector 8 for the current injection / ignition target cylinder #i is started, that is, fuel injection. Is started, it is determined whether the pull-up current is being supplied to the injectors of the other cylinders based on the value of the pull-up flag FPUL. If the pull-up current is being supplied to the injectors of the other cylinders, this pull-up current is determined. Energization of the injector 8 of the cylinder #i is started.
[0153]
Before describing the procedure for controlling the fuel injection start timing according to the present embodiment, the operation of the injector drive circuit 48a will be briefly described.
[0154]
The injector drive circuit 48a is provided corresponding to each high-pressure injector 8. In each injector drive circuit 48a, when an injection pulse signal instructing fuel injection is input, first, the valve body of the high-pressure injector 8 is moved at high speed. In order to open the valve, a large current (so-called pull-up current) is energized for a short time, and then the energization is temporarily stopped to decrease the energizing current value, and the energizing current to the high-pressure injector 8 is detected. Control is performed in a closed loop so as to obtain a holding current necessary for holding the valve open state of the body.
[0155]
This holding current is smaller than the pull-up current, and even if this holding current overlaps between cylinders, the burden on the injector driving power source is small. Therefore, in this embodiment, the energization start timing for the high-pressure injectors 8 between the cylinders is adjusted so that only the pull-up energization periods do not overlap.
[0156]
Here, a specific example of detecting the pull-up energization period according to the present embodiment will be described based on the circuit example of the injector drive circuit 48a shown in FIG.
[0157]
The injector drive circuit 48a shown in the figure includes a timing signal generation circuit 151, a flywheel circuit control signal generation circuit 151a, a boost power supply circuit 60 including a DC-DC converter, a current control circuit 70, a current detection circuit 80, and a flywheel circuit 90. The driving power supply VB is applied to the boosting current circuit 60 and the current control circuit 70.
[0158]
The timing signal generation circuit 151 includes a one-shot multivibrator 152 for generating a valve-opening current application time pulse signal SD to the boost power supply circuit 60 and the current control circuit 70, and a signal SC for determining the control timing of the flywheel circuit 90. A one-shot multivibrator 153, an EX-OR gate 154, an OR gate 155, and the like, and a flywheel circuit control signal generation circuit 151a.
[0159]
The one-shot multivibrators 152 and 153 are retriggerable types having external terminals CX and RX for connecting a CR for determining the output pulse width and two trigger input terminals A and B. Yes, an injection pulse signal is input to each trigger input terminal B for triggering at the rising edge of the signal, and each trigger input terminal A for triggering at the falling edge of the signal is grounded.
[0160]
Further, the external terminal CX of the one-shot multivibrator 152 is connected to the negative side of the capacitor 156, and the positive side of the capacitor 156 and one end of the resistor 157 are connected to the external terminal RX. One end is connected to the constant voltage power supply VCC. Similarly, the negative terminal of the capacitor 158 is connected to the external terminal CX of the one-shot multivibrator 153, and the positive terminal of the capacitor 158 and one end of the resistor 159 are connected to the external terminal RX. One end is connected to the constant voltage power supply VCC. Further, the non-inverting output terminal Q of the one-shot multivibrator 153 is connected to one input terminal of the EX-OR gate 154, and an injection pulse signal is applied to the other input terminal of the EX-OR gate 154. Entered.
[0161]
In the present embodiment, the non-inverting output terminal Q of the one-shot multivibrator 153 is connected to the interrupt terminal of the I / O interface 45, and the pull-up current energizing period is detected by the output signal from the non-inverting output terminal Q. is doing.
[0162]
Further, the non-inverting output terminal Q of the one-shot multivibrator 152 is connected to the current control circuit 70 and to one input terminal of the OR gate 155, and the other input terminal of the OR gate 155 is connected to the other input terminal. The output terminal of the EX-OR gate 154 is connected. The output terminal of the OR gate 155 is connected to the flywheel circuit 90, and the flywheel circuit control signal SE is output.
[0163]
Note that the inverted output terminals * Q of the one-shot multivibrators 152 and 153 are not used and are therefore open.
[0164]
When a high-level injection pulse signal is output from the I / O interface 45 of the control device 40 to the injector drive circuit 48a, the one-shot multivibrators 152 and 153 are triggered at the rising edge, and each non-inverted output terminal Signals SD and SC having a constant pulse width (high level) are output from Q, respectively.
[0165]
The pulse width of the signal SD output from the one-shot multivibrator 152 is determined by an external capacitor 156 and a resistor 157, and a high current (so-called pull-up current) at the time of valve opening is supplied to the high-voltage injector 8. Determine the period (about several hundreds of microseconds). The signal SD is output as a valve-opening current application time pulse signal to the boosting power supply circuit 60 and the current control circuit 70. The boosting power supply circuit 60 receives the output of the signal SD and receives a 12V driving power supply VR. Is output to the current control circuit 70. The current control circuit 70 outputs a large pull-up current using the high voltage, opens the high-pressure injector 8 at a high speed, and directly injects the high-pressure fuel into the combustion chamber 5 of the engine 1.
[0166]
On the other hand, the values of the external capacitor 158 and the resistor 159 are set so that the pulse width of the signal SC output from the one-shot multivibrator 153 is longer than that of the signal SD output from the one-shot multivibrator 152. When this signal SC is input to the EX-OR gate 154, a waveform obtained by inverting the signal SC from the EX-OR gate 154 by exclusive OR of the high level injection pulse signal and the signal SC is set. Is output.
[0167]
As shown in FIG. 31, the output signal of the OR gate 155 to which the signal SD and the signal from the EX-OR gate 154 are input, that is, the flywheel circuit control signal SE is obtained by inverting the signal SC and the signal SD. When the falling edge of the pulse width of the signal SC decreases the current of the high voltage injector 8 from the large current (pull-up current) at the time of opening the valve, the flywheel circuit 90 is started. It is time to activate.
[0168]
Next, the fuel injection start timing control procedure of the present embodiment will be described.
[0169]
In the I / O input voltage level L → H interrupt routine shown in the flowchart of FIG. 32, the voltage level of the signal SC input from each injector drive circuit 48a to the interrupt terminal of the I / O interface 45 is changed from low level to high level. In the routine activated when the level is switched, and in the I / O input voltage level H → L interrupt routine shown in the flowchart of FIG. 33, the voltage level of the signal SC input to the interrupt terminal is high. It is a routine that is activated by an interrupt when the level is switched to the low level.
[0170]
As shown in FIG. 31, when an injection pulse signal is input to an injector drive circuit 48a of a certain cylinder, a high level signal Sc is output from the non-inverting output terminal Q of the one-shot multivibrator 153 of the injector drive circuit 48a. When the routine shown in FIG. 32 is interrupted, the pull-up flag FPUL indicating that the pull-up current is energized is set in step S171 and the routine is exited.
[0171]
Next, when the signal Sc output from the non-inverted output terminal Q is switched to the low level, the routine shown in the flowchart of FIG. 33 is interrupt-activated. First, in step S181, the pull-up flag is turned on due to the end of energization of the pull-up current. FPUL is cleared, and the value of the injection delay flag FINJ is referred to in step S182. If FINJ = 1, the process proceeds to step S183. If FINJ = 0, the routine is directly exited. This injection delay flag FINJ is set in an injection start timing routine shown in the flowchart of FIG. 34 to be described later. When FINJ = 1, it indicates that there is a cylinder waiting for injection because the pull-up energization period overlaps. , FINJ = 0 indicates that no cylinder is waiting.
[0172]
When there is an injection standby cylinder of FINJ = 1, the process proceeds to step S183, where the fuel injection timer of the cylinder #i that is in standby is started, and the fuel injection of the cylinder #i, that is, the injector of the cylinder #i is started. In step S184, the counting of the injection start delay time TMt # i of the cylinder #i being counted is stopped. This injection start delay time TMt # i starts to be measured in an injection start timing routine shown in FIG. 34, which will be described later, and is stopped in step S184, so that the pull-up current energization of the high pressure injector 8 between the cylinders is performed. This represents the time during which the fuel injection timing of the cylinder #i is delayed so as to avoid duplication of the period, and the value of this injection start delay time TMt # i is read out in step S155 of the ignition control routine of FIG. When the fuel injection timing is delayed during stratified combustion, Reference example In the same manner as described above, the ignition timing of the cylinder #i is delayed.
[0173]
Next, in step S185, the injection delay flag FINJ is cleared and the routine is exited.
[0174]
On the other hand, said Reference example The injection start timing IJST [msec] set in the injection start timing timer started in step S75 of the start dwell start timing timer / post-start injection start timing timer start routine which is interrupted by the input of the θ1 pulse shown in FIG. When the measurement of the time is finished, the injection start timing routine shown in the flowchart of FIG. 34 is interrupted and activated. Then, after clearing the injection start delay time count value TMt # i of the current injection / ignition target cylinder #i in step S191, the process proceeds to step S192, and the value of the pull-up flag FPUL is referred to set the injectors of other cylinders. On the other hand, it is determined whether or not the pull-up current is energized. If FPUL = 0 and there is no pull-up energized cylinder, in steps S193 and S194, the ignition timing change flag FD # i of the cylinder #i, the injection delay, and so on. Each of the flags FINJ is cleared, and in step S195, the fuel injection timer for the cylinder #i is started and the routine is exited.
[0175]
Accordingly, when the fuel injection of the current injection / ignition target cylinder #i is started, if the pull-up current is not energized to the injectors of the other cylinders, the cylinder at the initial injection start timing IJST Fuel injection is performed immediately on #i.
[0176]
On the other hand, when FPUL = 1 in the above step S192 and the fuel injection of the current injection / ignition target cylinder #i is started and the pull-up current is being supplied to the injectors of other cylinders, the process branches to step S196. In order to delay the fuel injection start timing of the cylinder #i and correspondingly delay the ignition timing of the cylinder #i, in step S196, the ignition timing change flag FD # i of the cylinder #i In step S197, the measurement of the injection start delay time TMt # i for the cylinder #i is started, and in step S198, the injection delay flag FINJ is set, and the routine is exited.
[0177]
As a result, when the fuel injection is started for the current injection / ignition target cylinder #i, the fuel injection start timing is delayed when the pull-up current is being supplied to the injectors of the other cylinders. When the energization of the pull-up current to the injectors of the other cylinders is completed, the I / O input voltage level H → L interrupt routine of FIG. 31 is started as described above. At this time, the injection delay flag FINJ is set in step S198. By setting, in the I / O input voltage level H → L interrupt routine, the routine proceeds from step S182 to step S183, the fuel injection timer of the cylinder #i is started, and the pull-up current is supplied to the injectors of the other cylinders. After the end, energization of the pull-up current is started to the high-pressure injector 8 of the current injection / ignition target cylinder #i, and the fuel injection pulse width Ti set in the fuel injection timer is measured via the injector drive circuit 48a. An injection signal is output to the high pressure injector 8 of the cylinder #i and fuel is injected into the cylinder #i. Is done.
[0178]
Therefore, for example, as shown in FIG. 35, when the combustion mode is switched from stratified combustion to uniform combustion, at the normal injection start timing of the first injection / ignition cylinder # 1, the # 2 cylinder injector 8 When the pull-up current energization period overlaps, the energization of the # 1 cylinder injector 8 is started after the end of energization of the pull-up current. Since the energization period of this pull-up current is extremely short (about several hundred μsec), the delay of the fuel injection start timing can be minimized.
[0179]
In the present embodiment, the above-mentioned Reference example In the same way as above, after the energization of the pull-up current to the injectors of the other cylinders and after the set time TMs has elapsed, the fuel injection to the current injection / ignition target cylinder #i, that is, the energization of the injectors of the cylinder #i You may make it do. In addition, the present invention is not limited to the above embodiment, and for example, the pull-up current may be controlled using a 12V power supply without using the boost power supply circuit 60. Also, as shown in Japanese Patent Application No. 7-95362 filed earlier by the present applicant, when injecting twice in order to add post-combustion per cycle, Reference example Then, when this post-injection and main injection overlap between cylinders, control is performed so that the periods of both injections do not overlap. Fruit In the embodiment, control is performed so that the pull-up current conduction periods of the main injection and the post-injection do not overlap.
[0180]
【The invention's effect】
As described above, according to the first aspect of the present invention, when energization of the high-pressure fuel injection valve of the current fuel injection target cylinder is started, the valve opening pull-up current for the fuel injection valves of the other cylinders is started. When the pull-up current is being applied to the fuel injection valves of the other cylinders, the pull-up current is not supplied to the fuel injection valves of the other cylinders. Since energization to the fuel injection valve of the current fuel injection target cylinder is started so that only the period does not overlap, there is no overlap of pull-up current energization to the fuel injection valve between the cylinders, and therefore the fuel injection valve drive The burden on the power supply is reduced, the malfunction of the fuel injection valve due to a voltage drop is avoided, the proper fuel injection amount can be always supplied, and the durability is excellent. Without changing the structure of simply it can be realized at a low cost because it can only deal with software changes.
[0181]
In addition, since the energization period of the pull-up current is extremely short, the delay of the fuel injection start timing can be minimized, and can be realized without causing deterioration in combustibility due to the delay of the fuel injection start timing. .
[0182]
Further, in the invention according to claim 2, in addition to the above effect, when stratified combustion is selected, the ignition of the cylinder corresponding to the change in the start of energization of the fuel injection valve of the cylinder, that is, the delay of the fuel injection timing Since the timing is retarded, the interval between the fuel injection end timing and the ignition timing is always properly maintained during stratified combustion even if the fuel injection timing is delayed, and a rich mixture is formed around the spark plug during ignition. Thus, it is possible to reliably prevent the deterioration of ignitability associated with the change of the fuel injection timing.
[Brief description of the drawings]
FIG. 1 is a basic configuration diagram of the present invention.
FIG. 2 of the present invention Reference example Of the cylinder discrimination / engine speed calculation routine
FIG. 3 is a flowchart showing a start determination routine.
FIG. 4 is a flowchart showing a fuel injection pulse width / injection start timing setting routine.
FIG. 5 is a flowchart showing a fuel injection pulse width / injection start timing setting subroutine;
FIG. 6 is a flowchart showing a fuel injection pulse width / injection start timing setting subroutine (continuation).
FIG. 7 is a flowchart illustrating a fuel injection pulse width / injection start timing setting subroutine (continuation).
FIG. 8 is a flowchart showing an ignition timing / energization start time setting routine.
FIG. 9 is a flowchart showing the ignition timing / energization start time setting routine (continuation).
FIG. 10 is a flow chart showing a start dwell start timing timer and a post-start injection start timing timer start routine.
FIG. 11 is a flowchart showing an after-start ignition timing timer start routine.
FIG. 12 is a flowchart showing a start-up fuel injection timer, an ignition timing timer, and a post-start dwell start timing timer start routine.
FIG. 13 is a flowchart showing an injection start timing routine.
FIG. 14 is a flowchart showing an injection start routine of the above.
FIG. 15 is a flowchart showing a dwell start routine as above;
FIG. 16 is a flowchart showing an ignition control routine.
FIG. 17 is a flowchart showing an ignition routine as above;
FIG. 18 is an overall schematic diagram of a cylinder direct injection multi-cylinder engine as above.
FIG. 19 is a side view of the crank angle detecting crank rotor and the cylinder discriminating crank rotor that are attached to the crankshaft, and sensors provided to the crank rotor.
FIG. 20 is a front view of the crank angle detection crank rotor and the crank angle sensor provided on the crank rotor.
FIG. 21 is a front view of the cylinder discrimination crank rotor and a cylinder discrimination sensor provided on the crank rotor.
FIG. 22 is a circuit configuration diagram of the electronic control system as above.
FIG. 23 is the same as above, and fuel injection and ignition timing diagrams during uniform combustion
[Fig. 24] Same as above, stroke diagram during uniform combustion
FIG. 25 is a diagram of fuel injection and ignition timing during stratified combustion
Fig. 26 Same as above, stroke diagram during stratified charge combustion
FIG. 27 is a timing chart showing fuel injection and ignition at start-up.
FIG. 28 is a timing chart showing fuel injection and ignition after start-up.
FIG. 29 is a timing chart showing a correction state of the fuel injection timing when the fuel injection between the cylinders is the same as above.
FIG. 30 shows the present invention. The fruit The circuit diagram of the injector drive circuit according to the embodiment
FIG. 31 is a signal waveform diagram of each part of the injector drive circuit.
FIG. 32 is a flowchart showing an I / O input voltage level L → H interrupt routine.
FIG. 33 is a flowchart showing an I / O input voltage level H → L interrupt routine.
FIG. 34 is a flowchart showing an injection start timing routine as above.
FIG. 35 is a timing chart showing the correction state of the fuel injection start timing when the pull-up current energization periods between the cylinders overlap.
[Explanation of symbols]
1 In-cylinder direct injection multi-cylinder engine 6a Igniter 6b Ignition coil 7 Spark plug 8 High-pressure injector (fuel injection valve) 40 Control device 48a Injector drive circuit 50 Battery (power supply for fuel injection valve drive)

Claims (2)

In a cylinder direct injection multi-cylinder engine in which fuel is directly injected into a cylinder of each cylinder and burned,
Pull-up current end determining means for determining whether energization of the valve-opening pull-up current to the fuel injection valves of the other cylinders is completed when energization of the high-pressure fuel injection valves of one cylinder is started;
When the pull-up current is being applied to any of the fuel injection valves of the other cylinders, after the energization of the pull-up current of this cylinder is completed, only the energization period of the pull-up current is not duplicated. A control device for a direct injection type multi-cylinder engine having fuel injection valve energization control means for starting energization of a fuel injection valve of one cylinder. In the control apparatus for a direct injection multi-cylinder engine according to claim 1,
Stratified combustion determination means for determining selection of stratified combustion based on the engine operating state;
In-cylinder directing further comprising ignition timing changing means for retarding the ignition timing of the cylinder in response to a change in energization start of the fuel injection valve of the one cylinder when the stratified combustion is selected Control device for injection multi-cylinder engine.

Images