JP2755008B2 - Ignition control device for internal combustion engine with valve stop mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can operate in a cylinder-stop operation mode by stopping intake / exhaust valves of a cylinder set in an internal combustion engine in a timely manner and driving cylinders other than the cylinder having a cylinder stop. More particularly, the present invention relates to an ignition control device for an internal combustion engine having a valve stop mechanism, wherein an ignition control means determines an ignition timing in accordance with an operating condition of the engine and performs an ignition process.

[0002]

2. Description of the Related Art In a spark ignition engine, electronic control for optimally controlling the ignition timing according to operating conditions has been advanced. The control method is based on a reference signal indicating a specific crank position before TDC and a crank angle signal (pulse generated in units of 1 ° or 2 °), and according to the operating conditions at that time. The ignition timing and dwell angle are obtained, and the current to the ignition coil is turned on and off by a switching transistor (power transistor).

Here, the time during which the ignition coil is energized is represented by a crank angle, which is referred to as a dwell angle. The dwell angle becomes smaller as the engine rotates at a lower speed. Here, since the ignition timing changes the output generated by each cylinder, it is advanced as much as possible within a range where knock does not occur in a steady state, and a complete explosion is achieved. In such basic control of the ignition timing, the advance angle corrected for the reference advance amount according to the operating conditions, for example, the engine speed, the load, the change amount of the load, the cooling water temperature, etc., during the steady operation of the internal combustion engine. The ignition timing is controlled by using a fixed advance value during a transition period in which the amount of change in the load exceeds a certain value.

By the way, during operation of the internal combustion engine, in order to reduce the output and fuel consumption in a timely manner, the intake and fuel supply to some of the closed cylinders are stopped, and a valve capable of performing the closed cylinder operation. An internal combustion engine provided with a stop mechanism is known.
Control means for controlling a valve stop mechanism of this kind of internal combustion engine stops the opening / closing operation of the intake / exhaust valves of the cylinders and stops fuel supply to the cylinders when the engine enters a set operation area based on various operation information. When the supply is stopped and the vehicle leaves the set operation range, the opening / closing operation of the intake / exhaust valves of the cylinders in the closed cylinder is returned to a normal state, and the supply of fuel to the cylinder in the closed cylinder is restarted. The ignition device used here continuously performs the ignition process regardless of whether the engine is in a normal operation or a cylinder-stopped operation. Thus, by performing the ignition process continuously even during the cylinder deactivated operation,
The ignition current flowing through the ignition plug prevents the plug from being stained, so that the ignition processing at the time of returning to the all-cylinder operation again can be performed accurately.

[0005]

However, fuel is not supplied to the cylinders during cylinder deactivation, and ignition processing is not required except for the purpose of plug cleaning. That is, one ignition process usually requires 10 to 20 (W / h) of electric power, and the ignition process of the closed cylinder should be stopped in order to improve fuel efficiency. However, it is relatively easy to stop the ignition of the deactivated cylinder if the cylinder has an ignition circuit independent of each cylinder. With the ignition circuit having the above-mentioned ignition circuit, it is not possible to stop the ignition processing of only some of the cylinders in a closed cylinder, which is a problem.

It is an object of the present invention to provide an ignition control device for an internal combustion engine having a valve stop mechanism which can prevent contamination of a plug and improve fuel economy without increasing costs.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention comprises a cylinder having a closed cylinder in which at least one of an intake / exhaust valve is stopped by a valve stop means when the cylinder is operated in a cylinder-stop operation mode. The ignition control means of the internal combustion engine determines the ignition timing of both groups in accordance with the operating conditions, and the ignition control means of the internal combustion engine determines the ignition timing of both groups. An ignition timing control device for an internal combustion engine having a valve stop mechanism for performing control, wherein said ignition control means thins out a predetermined number of times of group ignition processing of ignition drive means of said cylinder group when said cylinder is in operation in a cylinder deactivated operation mode. Is performed.

[0008]

The ignition control means of the internal combustion engine determines the ignition timing of both groups according to the operating conditions. Group ignition control, the ignition control means operates in the cylinder-stop operation mode,
The group ignition process of the ignition drive means of the cylinder group of the cylinders in a cylinder stall can be thinned out by a predetermined number of times.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The ignition control apparatus for an internal combustion engine with a valve stop mechanism shown in FIG. 1 is mounted on an in-line four-cylinder internal combustion engine (hereinafter simply referred to as engine 1). The cylinder head 2 of this engine 1
Are formed with an intake path and an exhaust path (not shown) that can communicate with each cylinder, respectively, and each flow path is opened and closed by an intake valve and an exhaust valve (not shown). These intake and exhaust valves (not shown) are opened and closed by an intake cam 5 and an exhaust cam 6 via respective rocker arms 3a, 3b, 4a, 4b. Here, each rocker arm 3a, 3b, 4a, 4b is connected to a suction / discharge rocker shaft 7,
8, the air supply cam 5 and the exhaust cam 6 are formed integrally with the cam shaft 9.

A timing gear 11 is integrally attached to one end of the camshaft 9, and this timing gear is connected to a crankshaft (not shown) via a timing belt 13 so that the camshaft 9 can rotate at half the engine speed. The camshaft 9 is configured to rotate. Reference numerals 18, 19, and 20 in FIG. 1 indicate bearings that support each shaft. In FIG. 1, the second cylinder (# 2) as the operating cylinder
Each of the rocker arms 3b and 4b of the third cylinder (# 3) can always open and close the intake / exhaust valve, and the first cylinder (# 3) as a closed cylinder can be opened and closed.
1) and each rocker arm 3 against the fourth cylinder (# 4)
A and 4a are provided with a valve stop mechanism M that can stop the opening and closing operation of the suction and discharge valve at a predetermined time. Here, the valve stop mechanism M switches the valve pressing piece (not shown) on each rocker arm 3a, 4a between the valve opposing position and the retreat position by hydraulic switching means, and causes the valve pressing operation of the rocker arm to miss when the valve stops. Is adopted.

Here, the hydraulic oil is supplied from the hydraulic circuit 23 to the hydraulic switching means of the valve stop mechanism M. The hydraulic circuit 23 receives pressure oil supplied to and discharged from the valve stop mechanism M from the hydraulic pressure supply means 22 via the cylinder-stop solenoid valve 21. The hydraulic supply means 22 comprises a hydraulic pump and an oil tank as shown. The cylinder-stop solenoid valve 21 is a three-way valve that supplies pressure oil to each valve stop mechanism M when it is on, switches and holds the mechanism M to a valve stop state, and eliminates pressure oil for each valve stop mechanism M when it is off. Then, the mechanism M is switched to valve drive and held, and is driven and controlled by an engine control unit 24 described later.

Further, an injector 25 for injecting fuel into an intake port (not shown) of each cylinder is mounted on the cylinder head 2 shown in FIG. 1, and each injector supplies fuel whose constant pressure has been adjusted by a fuel pressure adjusting means 26 from a fuel supply source 27. received,
The injection drive control is performed by the engine control unit 2
4 Further, the cylinder head 2 of FIG. 1 is provided with an ignition plug 14 for each cylinder. In particular, both plugs 14 of the constantly operating cylinders # 2 and # 3 are connected together to form an ignition coil as a single ignition driving means. 37 ', a power transistor 38' and a drive circuit 34. Both plugs 14 of the cylinders # 1 and # 4 are connected together to form an ignition coil 37 as a single ignition drive means, a power transistor 38 and a drive circuit. 35. Both drive circuits 34,
Reference numeral 35 denotes both output circuits 36 and 36 'of the engine control unit 24 (both circuits have the same configuration and only one is shown in FIG. 2).

Both output circuits 36 and 36 'are connected to cylinders # 1 and # 2, respectively.
The # 4 group is connected to the always-operated cylinders # 2 and # 3 groups, respectively, and both are a reference signal (（o in crank angle) and a crank angle signal (pulse in units of 1 ° or 2 ° (Δθ))
In FIG. 2, the cylinders # 1 and # 4 are shown in FIG.
The ones in the group are shown, and those in the constantly operating cylinders # 2 and # 3 are omitted. Here, the reference signal ψo is a one-shot circuit B
To the one-shot circuit B during normal operation.
Is triggered by a reference signal ψo (off-on) before ψo (for example, 75 °) before top dead center, and a crank angle signal Δθ (1 °
Alternatively, an energization start signal is output after counting a predetermined number of pulses (in units of 2 °) (delay time t1 corresponding to reaching the ignition timing (ψo-ψt)) (see FIG. 4). . In this case, the target ignition timing Δt is obtained in step a5 of the flowchart of FIG. 5 described later.

The one-shot circuit A is configured to be triggered by the energization start signal, count a predetermined number of crank angle signals corresponding to the dwell angle, and output an ignition signal. The flip-flops FF are set by an energization start signal from the one-shot circuit B and reset by an ignition signal from the one-shot circuit A. Further, when the flip-flop 7 is in the set state, the drive circuit 35 turns on the power transistor 38 in response to the output signal, and causes the current to flow to the ignition coil 37. When the power transistor 38 is turned off, the ignition coil 37 generates a high-voltage current on the secondary side.
The sparks are transmitted to the spark plugs 1 and # 4, and the cylinders in the closed cylinder group are ignited.

Similarly, the output circuit 36 'of the constantly operating cylinders # 2 and # 3 is also configured, and the secondary high voltage of the ignition coil 37' is supplied to the constantly operating cylinders # 2 and # 2 at the target ignition timing #t.
The sparks are supplied to both spark plugs # 3, and the group ignition of the constantly operating cylinders is performed. FIG. 4 shows all cylinders # 1, # 2, and # 2 in all cylinder operation mode and closed cylinder operation mode.
An example of the group ignition timings of # 3 and # 4 is shown. Here, the ignition timing of both groups is approximately 180 ° crank angle.
Are performed alternately for each group while maintaining the intervals. On the other hand, in the cylinder-stop operation mode, as described later, only the group ignition processing of the cylinders # 1 and # 4 is ignited by the number of thinning times α to perform the ignition processing.

Engine control unit (ECU)
Reference numeral 24 particularly has a function as an ignition control means, a main part of which is constituted by a microcomputer. The microcomputer 24 performs well-known control processing such as fuel supply control to the engine 1, throttle valve drive control, and the like. It also controls. In this fuel supply control, the basic fuel pulse width Tf based on the intake air amount is calculated, and the fuel driving control is multiplied by the air-fuel ratio and other correction coefficients to determine the injector driving time. ) Is a closed cylinder.
A well-known injector drive control process of driving the injectors 25 of only the always-operated cylinders # 2 and # 3 excluding the cylinders # 1 and # 4 and driving the injectors 25 of all cylinders during all-cylinder operation is performed.

The engine control unit 2 here
4, a rotation speed Ne of the engine 1 from the engine rotation sensor 30, information on the intake air amount A from the air flow sensor 31, a vehicle speed Sv from the vehicle speed sensor 32, a unit crank angle signal Δθ from the crank angle sensor 33, a cylinder discrimination sensor 3
4, a reference signal ψo (here, emitted at every 180 ° crank angle) is taken in, and various other operating information such as throttle opening information and water temperature are taken in. FIGS. 5 and 6 show a flowchart of a control program of the ECU 24 used in the ignition timing control device of the internal combustion engine with the valve stop mechanism as one embodiment of the present invention.

The ECU 24 starts the control in the main routine when a main switch (not shown) is turned on.

Here, first, an initial function set such as a check of each function and an initial value set is performed, and subsequently, various operation information of the engine is read. Then, the process proceeds to step a3, in which a well-known cylinder stop control routine (not shown) is executed as the cylinder stop control processing. Here, for example, control is performed such that the cylinder deactivation process of the first and fourth cylinders # 1 and # 4 is performed at an appropriate time during the constant-speed running at a medium to low load. The input command is issued by switching the cylinder-stop flag ICFLG.

In the dwell angle determination processing at step a4, the dwell angle at each ignition processing is calculated based on the engine speed Ne. In the ignition timing calculation process in step a5, a known process of obtaining the target ignition timing Δt by correcting the reference ignition timing with the engine water temperature, the engine speed, the load, etc. is performed, and the target ignition timing Δt is determined. When step a6 is reached, other control of the engine, for example, calculation processing of the fuel injection amount and the like are executed, and the processing of the control cycle is ended.
To return.

The ignition control routine shown in FIG.
° (75 ° BTDC) (crank angle 180
The main routine is interrupted and executed based on the change of the reference signal ψo from off to on at (°). At step b1 here, the on / off information of the cylinder-stop flag ICFLG, cylinder discrimination information (determined from the reference signal $ o) and the like are taken in. At step b2, it is determined whether or not ICFLG is on. When the cylinder is turned on and in step b3, this time is the cylinder # 1 that is closed.
The process proceeds to step b4 only when it is determined that the ignition timing period is 4, and otherwise proceeds to step b6.

In step b6, a cylinder-stop cycle number counter K, which will be described later, is cleared, and the flow advances to steps b8 and b9 to set the latest dwell angle in the one-shot circuit A. Furthermore,
The latest target ignition timing Δt is set in the one-shot circuit B, and the process returns to the main routine. This step b6
Is reached during the ignition processing of the always-operated cylinders # 2 and # 3 in the all-cylinder operation mode or the closed-cylinder operation mode, and one of the first and fourth cylinder groups (or the second and third cylinder groups) is compressed. The fuel is ignited near the dead center and proceeds to the explosion stroke (indicated by the symbol ▽ in FIG. 4), and the other is ignited in the vicinity of the exhaust top dead center. Similarly, when a crank angle of 180 ° has elapsed, at this time, one of the second and third cylinders is ignited near the compression top dead center and proceeds to the explosion stroke, and the other is idle ignited near the exhaust top dead center.

When the ICFLG is turned on by the cylinder stop command and the current time is determined to be the ignition timing cycle of the cylinders # 1 and # 4, the process proceeds to step b4, in which an injector drive stop command is issued and the process proceeds to step b5. In step b5, the cylinder-stop cycle number counter K is set to a preset thinning number α.
It is determined whether or not the number is greater than (here, set to 2). If not, the process proceeds to step 7, adds and updates the value of the cylinder-stop cycle number counter K by 1, and returns to the main routine. That is, in the crank angle positions corresponding to K = 1 and K = 2 in FIG. 4, the ignition processing of the cylinders # 1 and # 4 is not performed.
Improve fuel economy by eliminating ignition processing.

On the other hand, if the cylinder-stop cycle number counter K exceeds the number of thinning times α (= 2) in step b5, step b1 is executed.
The routine proceeds to 0, a preset constant dwell angle is set in the one-shot circuit A, and a preset constant ignition timing Δt1 is set in the one-shot circuit B. Clear the value of K and return to the main routine.

In this case, in the cylinder-stop operation mode, the group ignition processing of the cylinders # 1 and # 4 is not skipped by a predetermined number of times (in this case, twice), and the cylinder-ignition cylinders # 1 and # 4 are executed the next time. If the # 4 group ignition process is performed once, the process of thinning out the ignition twice again will be repeated. As a result, a reduction in fuel consumption due to useless ignition processing is suppressed, and the ignition plugs 14 of the cylinders # 1 and # 4 are idle-ignited every time the number of thinnings 2 elapses, so that contamination of the ignition plugs 14 can be prevented. There is also an advantage that a proper ignition process can be performed when the operation of all cylinders is returned again.

[0026]

As described above, according to the present invention, the ignition timing is determined in accordance with the operating conditions, and the group ignition control of both the ignition driving means of the cylinder group of the cylinders of the internal combustion engine and the cylinder group of the continuously operating cylinders is performed. During the operation in the cylinder-stop cylinder operation mode, the group ignition process of the ignition driver of the cylinder group of the cylinder-stop cylinder is stopped, and the group ignition process of the ignition driver of only the cylinder group of the always-operated cylinder is performed by thinning out the number of times. Dirt can be prevented, and fuel efficiency can be improved without increasing costs.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an ignition timing control device for an internal combustion engine with a valve stop mechanism as one embodiment of the present invention.

FIG. 2 is a main block diagram of an ignition drive unit and an ignition control unit in the ignition timing control device of FIG. 1;

FIG. 3 is a waveform diagram of an ignition drive performed by the ignition timing control device of FIG. 1;

FIG. 4 is an explanatory diagram of a change over time of an ignition process performed by the ignition timing control device of FIG. 1;

FIG. 5 is a flowchart of a main routine in a control program executed by an ECU in the apparatus of FIG. 1;

FIG. 6 is a flowchart of an ignition control routine performed by an ECU in the apparatus of FIG. 1;

[Explanation of symbols]

 1 Engine 2 Cylinder Head 14 Spark Plug 24 ECU 25 Fuel Injection Valve M Valve Stop Mechanism ψt Target Ignition Timing ♯o Reference Signal 常 時 2 Constantly Operating Cylinder ♯3 Constantly Operating Cylinder ♯1 Cylinder ♯4 Cylinder α

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 45/00 301 F02D 45/00 301D F02P 3/04 303 F02P 3/04 303G

Claims (1)

(57) [Claims] An ignition system includes a cylinder for stopping at least one of an intake / exhaust valve by a valve stopping means when the cylinder is in a cylinder-stop operation mode. Comprising driving means,
An ignition timing control device for an internal combustion engine with a valve stop mechanism, wherein the ignition control means of the internal combustion engine obtains the ignition timing of both groups according to operating conditions and performs group ignition control of the two ignition drive means. An ignition control device for an internal combustion engine with a valve stop mechanism, wherein the means for performing the group ignition processing of the ignition drive means of the cylinder group for cylinder deactivation during the operation in the cylinder deactivation mode is performed by thinning out the number of times.