JP2964128B2 - Control device for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for an internal combustion engine, and more particularly to an injection timing control in an internal combustion engine having a control sleeve type fuel injection pump. 2. Description of the Related Art Conventionally, injection timing is often adjusted by a mechanical timer, and it has been difficult to perform fine-grained control according to the operating conditions of an engine. In order to solve such problems, there is an electronic timer controlled by a control device using a microcomputer or the like. However, hydraulic power is used as a driving power, and the cam phase is controlled by the hydraulic pressure. Was generally changed (for example, JP-A-59-1478).
No. 35). However, in the case of a structure in which the cam phase is adjusted using hydraulic pressure, a considerable amount of power is required for driving, and fine control is difficult to perform because response is relatively poor. Was. On the other hand, a control sleeve type fuel injection pump is disclosed, for example, in Japanese Utility Model Publication No. 55-24371, filed by the present applicant.
It has the features that the power required for driving is very small and excellent responsiveness is obtained, and fine control according to the operating state of the engine is facilitated. FIG. 2 shows the structure of the main part of this type of fuel injection pump and the principle of operation relating to the injection timing adjustment. FIG. 2 (a) is at the time of fuel intake, (b) is at the time of starting pumping, and (c) is The end of the pumping is shown. In the drawing, 41 is a barrel, 42 is a plunger, 43 is a control sleeve fitted to the plunger 42 so as to be rotatable and movable in the axial direction. The plunger 42 has a suction port 45 and a discharge port at its lower part. 46
The control sleeve 4 is provided with a vertical hole 44 having
3 is provided with a peripheral groove 47. An eccentric pin 48 is engaged with the circumferential groove 47. The eccentric pin 48 is a fan-shaped adjusting plate 50 that meshes with a timer rack 49 for adjusting the injection timing.
The timer rack 49 is connected to a timer rack actuator (not shown) and is driven in a direction perpendicular to the plane of the drawing. Accordingly, the eccentric pin 48 eccentrically rotates in response to the operation of the timer rack actuator, and the control sleeve 43 moves in the axial direction to move the plunger 42.
The position of the control sleeve 43 with respect to the suction port 45 and the discharge port 46 changes, and the injection timing is adjusted. In the figure, 51 indicates a cam, 52 indicates a roller, and 53 indicates a tappet. SUMMARY OF THE INVENTION The present invention uses a control sleeve type fuel injection pump having the above-mentioned features, and is capable of appropriately controlling the injection timing according to various operating conditions. The object of the present invention is to improve the control at the time of emptying and at the time of abnormality. In order to achieve the above object, a first invention of the present application has a control sleeve fitted to a plunger so as to be rotatable and movable in an axial direction. A control sleeve-type fuel injection pump in which the control sleeve is moved in the axial direction to adjust the injection timing; an electric timer actuator for driving the control sleeve of the fuel injection pump; and an engine speed. The engine speed detecting means for detecting the actual value of the engine speed, and stores the desired relationship between the engine speed and the injection timing under various conditions including acceleration, and stores the desired relationship according to the detected engine speed and conditions. Control means for outputting a control signal for driving the timer actuator. After the engine is started, it is determined that the engine speed has fallen into an engine stall. If the reference rotation speed exceeds the reference rotation speed, an increase in the accelerator operation amount is detected, and if the increase amount has reached a preset acceleration recognition reference value, it is determined that the vehicle is in an acceleration state, and the acceleration noise during idle- up is detected. In order to obtain a predetermined injection timing from the desirable relationship between the engine speed and the injection timing that reduces the torque and increases the torque, the timer actuator is driven to perform acceleration control. A second aspect of the present invention provides a control sleeve type fuel injection pump, an electric timer actuator for driving the control sleeve of the fuel injection pump, and an actual engine speed as in the first aspect. The engine speed detecting means for detecting the value and a desirable relationship between the engine speed and the injection timing under various conditions are stored, and the timer actuator is driven in accordance with the detected engine speed and the condition. Control means for outputting a control signal for adjusting the position of the metering rack actuator before starting.
In determining an abnormality, also determines an abnormality from the output of the relationship after starting of the position of the adjusting rack actuator to the metering rack actuator, when it is determined as abnormal by driving the actuator for the timer The fuel injection pump is stopped by moving the control sleeve to the lower or upper limit position so as to close the suction port or open the discharge port of the fuel injection pump. Next, an embodiment of the present invention will be described. FIG. 1 is a conceptual system diagram, and 1 is a control sleeve type fuel injection pump as described in FIG.
2 is a metering rack actuator for fuel metering, 3 is a timer rack actuator for adjusting the injection timing, 4 and 5 are position sensors for each actuator, 6 is a rotation speed sensor, and 7
Is an accelerator position sensor, 8 is an accelerator, 9 is a cooling water temperature sensor, 10 is an intake air temperature sensor, 11 is a fuel temperature sensor,
Reference numeral 12 is a battery, and 13 is a key switch. The body of the engine is not shown. A well-known electric actuator using a linear solenoid, a stepping motor, or the like is used for the metering rack actuator 2 and the timer rack actuator 3. Are detected by the position sensors 4 and 5. The rotation speed of the engine is detected by detecting the movement of the groove 17 of the magnetic rotating body 16 attached to the camshaft 15 with the rotation speed sensor 6 including an electromagnetic pickup. Reference numeral 21 denotes a control unit for controlling the operating state of the engine in accordance with an operator's instruction. The control unit 21 is configured using, for example, a microcomputer, and includes an analog input port 22 to which various analog signals are input, a multiplexer 23, an A / D conversion unit 24, a digital input port 25 to which a digital signal is input, and a rotation speed. Waveform shaping circuit 26 to which a signal from sensor 6 is input, timer circuit 2
7, counter 28, RAM used for various control calculations
29, a ROM 30 storing a control program and various control data, a metering rack actuator driving circuit 3
1. A timer rack actuator drive circuit 32 and the like are provided, and these circuits are connected to a CPU 33 for giving various control calculations and input / output instructions. Note that the injection timing can be calculated from the relationship between the timer rack position detected by the position sensor 5 (a potentiometer, a gap sensor, etc., in addition to a differential transformer) and the timing of closing the suction port. Alternatively, the start of the lift of the nozzle may be detected by a sensor using the piezo effect, or the ignition state in the combustion chamber may be detected by a photo sensor, and the phase may be calculated from the phase relationship with the top dead center signal. In this case, the output of the sensor may be input through a waveform shaping circuit, similarly to the rotation speed sensor 6. Various state quantities other than those described above are also appropriately input through the input ports 22 and 25 and the like. The ROM 30 stores a desirable relationship between the engine speed and the injection timing in a steady operation state, a relationship between the two corresponding to an environmental condition such as a cooling water temperature at the time of starting that affects startability, and a relationship at the time of acceleration. Desirable relationships between the engine speed and the injection timing under various operating conditions, such as the relationship between acceleration noise and torque under conditions of priority, are stored. Hereinafter, an example in the case of a numerical table (map) will be described. FIG. 10A shows an example of a map of the timer rack position (Tss) at the time of starting control applied at the time of starting, and shows the actual engine speed (including the case of starting, that is, the case of zero speed). The relationship between the value Nacts and the timer rack position Tss is determined according to the cooling water temperature Tw, which is one of typical environmental conditions. In addition, as the environmental conditions, in addition to the cooling water temperature, an intake air temperature, a fuel temperature, a battery voltage, and the like can be used as needed. FIG. 10B is an example of a map of the timer rack position (Tset) during normal operation. This map is determined in accordance with the actual position Ract of the metering rack corresponding to the injection amount (load), and has various operating ranges for various characteristics such as noise, exhaust gas components such as NOx, fuel efficiency, and torque. Are set so as to satisfy the target characteristics in the most comprehensively. [0016] The metering rack also includes a starting control target metering rack position Rss suitable for starting and a steady operation target metering rack at which the engine is operated at a predetermined speed variation rate in accordance with the load. The position Rset is stored in the ROM 30 in the form of a map similar to (a) and (b) of FIG. Next, a description will be given with reference to a series of flowcharts shown in FIGS. Control is key switch 1
3 is input to the input port 25 and starts. First, the old data is cleared and the cooling water temperature T
w, the fuel temperature Tf, the intake air temperature Ti, etc., and the voltage coefficient MVB of the battery 12 are further recognized, and the target control rack position Rss for start control and the target timer rack position Tss for start control are determined from the above-described maps. Is done. Until the starter is driven, the operation state flag Drive and the engine stop state flag Stool are both 0, and the CPU 33 proceeds to steps S1 and S2 as it is, so that the position of the metering rack is Rss and the position of the timer rack is Tss. Output control signals Qout and Tout to the metering rack actuator drive circuit 31 and the timer rack actuator drive circuit 32. Thus, the metering rack actuator 2 and the timer rack actuator 3 are driven by a predetermined amount to prepare for starting the engine. In this start preparation state, the pre-start timer Ptime is counted, and if the starter is not driven by the pre-start timer end time Pend, the routine proceeds to step S3, where the engine stop state flag Stool is set to 1, and the control of the metering rack actuator 2 is performed. The output Qout and the output Tout to the timer rack actuator 3 are turned off, and the preparation for starting is terminated. The pre-start timer end time Pend is, for example, 4 to
It is selected to be about 10 seconds. On the other hand, if the starter is driven before the end time Pend of the pre-start timer, the operation state flag Dr
ive becomes 1, and the process proceeds to FIG. First, the actual value Nact of the engine speed is recognized, and the cooling water temperature Tw, the fuel temperature Tf, and the intake air temperature Tact are recognized.
i, environmental conditions such as the voltage coefficient MVB of the battery 12 are recognized again. The start recognition flag StOK is set to 1 when the rotation speed Nact becomes equal to or higher than the start recognition rotation speed Nst. When the rotation speed in the initial stage of the start is low, the process proceeds from step S6 to S7, where the metering rack position and the timer rack position are set. The target values Rss and Tss at the time of the start control are used, respectively, and the drive by the starter is continued while the numerical values are sequentially updated as the rotational speed increases. The start recognition rotation speed Nst is a reference rotation speed at which it is determined that the engine has started due to the complete explosion of the engine. When this rotation speed is reached, the start recognition flag StOK becomes 1 in step S8, and the start control is started. The process ends and the process proceeds to step S9. The engine-recognition rotational speed Nstool is the rotational speed Na.
If ct is less than this, it is a reference rotation speed at which it is determined that an engine stall has occurred.
Returning to FIG. 3 with rive set to 0 and the engine stall state flag Stool set to 1, the output to each actuator is turned off in steps S4 and S5. On the other hand, if the rotation speed Nact is larger than Nstool, the process proceeds to step S10, where the set value Nset of the rotation speed is recognized from the position of the accelerator 8, and the steady-state target metering rack position Rset and the steady operation timer rack position are set. It becomes a steady operation using Tset. As described above, since the timer rack actuator 2 is set before driving the starter to an appropriate position corresponding to the environmental conditions, the time required for the first explosion to start early and for the complete explosion even at a low temperature at which the startability decreases is reduced. This makes it possible to reduce inconvenience, such as the inability to restart the battery due to overdischarge of the battery and the generation of unburned gas or odorous gas. The first invention relates to control during acceleration. In addition to the above-described map, a map of the timer rack position Tset 'during acceleration operation as shown in FIG. 10C is prepared. This Tset 'is used when acceleration is attempted by operating the accelerator, and is a map that can reduce noise during acceleration and obtain a large torque. Is set to FIGS. 5 and 6 show a control procedure during the acceleration operation. FIG. 5 shows a procedure for detecting an acceleration state. The step of Nset recognition in step S10 in FIG. 4 is replaced with the procedure in FIG. Here, first, the engine speed setting value Nset is compared retroactively to the value three times before. When the set value is increasing and the difference is equal to or greater than the acceleration recognition reference value Nup, the acceleration recognition flag Nupc is set to 1
When the set value is decreasing, the deceleration recognition flag Ndnc is set to 1 if the difference is equal to or more than the deceleration recognition reference value Ndown, and the accelerator is not operated if there is no difference in the set value or the difference is smaller than the reference value. Therefore, both the acceleration recognition flag Nupc and the deceleration recognition flag Ndnc remain 0. When the acceleration recognition flag Nupc becomes 1 in the above procedure, control is performed by the acceleration operation timer rack position Tset 'in FIG. 10C as shown in FIG.
That is, Tse of step S10 and step S7 of FIG.
Since Tset 'is used in place of t, noise during acceleration is small, and a large torque suitable for acceleration can be obtained. Generally, after the start control is completed, step S9 is performed.
Immediately after the process proceeds to step S10 and the steady operation is performed,
The engine has just started self-sustaining operation and the engine warm-up is insufficient.
Therefore, in order to promote warm-up, a so-called idling operation is often performed in which the accelerator is operated with the clutch disengaged. At this time, since the control is performed by the timer rack position Tset 'during the acceleration operation as described above, the idle operation is performed. It is possible to obtain a sufficient torque while reducing the noise at the time of puffing. Therefore, warm-up can be performed without generating noise or engine stall, and the operation can be quickly and smoothly shifted to the rated operation in which a load is actually applied. Next, the control at the time of abnormality according to the second invention will be described. According to the present invention, in the control sleeve type fuel injection pump, the injection timing is adjusted by changing the timing of closing the fuel suction port of the plunger by the control sleeve, and the control sleeve is moved to a position where the suction port does not open at the phase on the cam base. If the fuel supply is lowered, the fuel supply can be stopped easily, and the safety in the event of a failure of the injection control system is improved. This fuel cut can be similarly performed by raising the control sleeve to the position where the discharge port opens. FIGS. 7 and 8 show the procedure of failure diagnosis.
8 shows the procedure of the pre-start diagnosis in step S11 shown by the broken line in FIG. 3, and FIG. 8 shows the procedure of the post-start diagnosis in step S12 shown by the broken line in FIG. In step S11, the actual value Ract of the metering rack position is recognized. If the actual value Ract is larger than the failure recognition rack position Rfail1, it is determined that an abnormality has occurred, and the failure flag Fail is set to 1. In step S12, an interruption process is performed at predetermined intervals during operation. If the output Qout to the metering rack actuator 2 is smaller than the failure recognition output Qfail1, a comparison is made again after the required operation time t3 of the actuator. If it is still smaller, the rack position Ract is compared with Rfail1, and if Ract is large despite Qout being small, it is determined that an abnormality has occurred and the failure flag Fail is set to 1. On the other hand, if the output Qout is not smaller than the failure recognition output Qfail1, Qou
Compare t with a second failure recognition output Qfail2 that is greater than Qfail1. If it is larger, the comparison is made again after the required operation time t3 of the actuator.
ct is compared with a failure recognition rack position Rfail2 which is larger than Rfail1. If Ract is small despite Qout being large, it is determined that an abnormality has occurred and the failure flag Fail is set to 1. FIG. 9 shows the output Q in step S7 of FIG.
This shows the calculation procedure of out. In a normal state, a calculated output Qout ′ is obtained by PI calculation from the difference between the target position Rset and the actual position Ract of the rack, and this is corrected by the voltage coefficient MVB of the battery 12 to obtain the output Qout. Ask for it. The voltage coefficient MVB is a ratio between the reference voltage and the actual voltage, and is used to compensate for a slow operation of the actuator when the voltage is low. It should be noted that exactly the same calculation processing is performed on the output Tout to the timer rack actuator 3. On the other hand, when the failure flag Fail is 1,
The output Tout to the timer rack actuator 3 is turned off. Thereby, the control sleeve of the fuel injection pump 1 is lowered to the lower limit position, the fuel is cut, and the engine is stopped. At the same time, an alarm is issued, the driving state flag Drive becomes 0, and the engine stall state flag Stool becomes 1. As described above, since the position of the control sleeve is controlled by the timer rack actuator 3, there is provided a means for adjusting the fuel injection amount, for example, when the rotation speed sensor 6 is degraded, disconnected, or the injection timing is greatly deviated. If the failure of the engine is detected due to a failure, the engine can be reliably stopped, and the engine remains stopped until the starter is driven again by the key. In this case, the safety at the time of abnormality can be further improved by using the fuel injection cut valve together with the injection stop. The engine can also be stopped by turning off the output Qout to the metering rack actuator 2. As is apparent from the above description, the invention of this application utilizes the features of the control sleeve type fuel injection pump which requires a small amount of power for driving and has good responsiveness. According to the first aspect of the invention, when the accelerator is operated immediately after the start operation and the self-sustaining operation are started, the idle
A timer actuator is driven to obtain an injection timing that reduces the acceleration noise at the same time and increases the torque, thereby performing acceleration control with low noise and high torque. Therefore, even if the so-called idling is performed for the purpose of promoting warm-up after the engine is started, the driving is not performed.
To quickly respond to the intention power operator for responsiveness is good small required and is possible to obtain a sufficient torque while reducing the noise, the generation and autonomous operation of the noise
Though not in operating the accelerator performs warm-up without such leading to engine stall, it is possible to actually rapidly yet smoothly shift to rated operation the load is turned on. According to a second aspect of the present invention, an abnormality is determined based on the relationship between the position of the metering rack actuator before starting and the position of the metering rack actuator after starting and the output to the metering rack actuator. If it is determined that the fuel injection pump is driven, the control sleeve is moved to the lower or upper limit position so as to close the suction port or open the discharge port of the fuel injection pump, and stop the fuel injection. It was done. [0038] Accordingly, it is possible to disable operation by detecting an abnormal even before the engine is started, also the case during operation
Since the power required for driving is small and the responsiveness is good , the fuel can be cut quickly and the engine can be reliably stopped, so that the safety in the event of a failure in the injection control system can be easily improved. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual system diagram of an apparatus according to an embodiment of the present invention. FIG. 2 is a view showing the structure and operation of a main part of a control sleeve type fuel injection pump used in the device;
(a) shows when fuel is sucked, (b) shows when pumping starts, and (c) shows when pumping ends. FIG. 3 is a flowchart showing a part of a control procedure of the apparatus. FIG. 4 is a flowchart showing a part of a control procedure. FIG. 5 is a flowchart showing a part of a control procedure. FIG. 6 is a flowchart showing a part of a control procedure. FIG. 7 is a flowchart showing a part of a control procedure. FIG. 8 is a flowchart showing a part of a control procedure. FIG. 9 is a flowchart showing a part of a control procedure. FIGS. 10A and 10B are diagrams exemplifying a control map in the same device, wherein FIG. 10A is for control at start-up, FIG.
(c) shows the control for acceleration. [Description of Signs] 1 fuel injection pump 3 timer rack actuator 6 rotation speed sensor 7 accelerator position sensor 21 control unit 30 ROM 33 CPU 42 plunger 43 control sleeve 45 suction port 46 discharge port 49 timer rack

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02D 41/40 F02D 1/02 F02D 45/00 F02M 59/26 F02M 59/44

Claims (1)

(57) [Claims] A control sleeve type fuel injection pump having a control sleeve fitted to the plunger so as to be rotatable and movable in the axial direction, wherein the control sleeve is moved in the axial direction to adjust the injection timing; An electric timer actuator for driving the control sleeve of the fuel injection pump; an engine speed detecting means for detecting an actual value of the engine speed; and an engine speed and injection timing under various conditions including acceleration. Control means for outputting a control signal for driving the timer actuator in accordance with the detected engine speed and conditions, and after the engine is started, the engine speed is controlled by the engine. If the engine speed exceeds the reference rotation speed at which it is determined that the engine has stalled, an increase in the accelerator operation amount is detected, and the increase amount is set to a preset value. If you have reached the fast recognition reference value is determined to be accelerating state, empty
It is characterized in that acceleration control is performed by driving the timer actuator to obtain a predetermined injection timing from a desirable relationship between the engine speed and the injection timing such that the acceleration noise at the time of puffing is reduced and the torque is increased. Control device for an internal combustion engine. 2. A control sleeve type fuel injection pump having a control sleeve fitted to the plunger so as to be rotatable and movable in the axial direction, wherein the control sleeve is moved in the axial direction to adjust the injection timing; An electric timer actuator for driving the control sleeve of the fuel injection pump, an engine speed detecting means for detecting the actual value of the engine speed, and a desirable relationship between the engine speed and the injection timing under various conditions. stored and, control means for outputting a control signal for driving the actuator for the timer in response to the detected engine speed and the condition includes a city, an abnormality in the position of the adjusting rack actuator before the start Size
Constant, and also determines an abnormality <br/> from the relationship between the output on this adjusting rack actuator and the position of the adjusting rack actuator after starting to drive the actuator for the timer when it is determined to be abnormal A control device for an internal combustion engine, wherein the fuel injection is stopped by moving a control sleeve to a lower or upper limit position so as to close a suction port or open a discharge port of a fuel injection pump.