JPH06108958A - Ignition control device for internal combustion engine with valve stop mechanism - Google Patents

Abstract

PURPOSE:To reduce the ignition process of cut-off cylinders for the cleanup of a spark plug when a cylinder cut-off mode continues for the specified time or more so as to pass the time when the fouling of the spark plug is considered to advance excessively. CONSTITUTION:An internal combustion engine with valve stop mechanism is provided with cut-off cylinders stopped by a valve stop means M during operation in a cylinder cut off operation mode, and independent ignition driving means 36 for No.1 and No.4 groups of the cut-off cylinders and No.2 and No.3 groups of constantly operated cylinders. An ignition control means 24 obtaines the ignition timing of both groups according to the operating condition so as to perform the group ignition control of both ignition driving means 36. The cylinder cut-off continuous time Tn in the cylinder cut off operation mode is counted by a cylinder cut-off time timer, and when the cylinder cut-off continuous time Tn counted by the cylinder cut-off time timer exceeds the set time T2, the ignition control means 24 switches an ignition process in the cylinder cut-off mode to a total cylinder mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can perform an operation in a cylinder deactivation mode by timely stopping the intake / exhaust valves of the cylinder deactivated cylinders of an internal combustion engine to drive cylinders other than the cylinder deactivated cylinder. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition control device for an internal combustion engine mounted on an internal combustion engine, and more particularly, an ignition control means determines an ignition timing according to an operating condition of the engine to perform an ignition process.

[0002]

2. Description of the Related Art In spark ignition engines, electronic control for optimally controlling ignition timing according to operating conditions has been advanced. The control method is to receive a reference signal indicating a specific crank position before the top dead center (TDC) and a crank angle signal (pulses generated in units of 1 ° or 2 °), and respond to the operating conditions at that time. Ignition timing, Ignition coil energization time is calculated by crank angle dwell angle,
The switching transistor (power transistor) turns on and off the current to the ignition coil.

Here, since the ignition timing increases / decreases the output generated by each cylinder, the ignition timing is advanced as far as possible in a range where knock does not occur in a steady state, and a complete explosion is achieved. In such a basic control of the ignition timing, in the steady operation of the internal combustion engine, the advance angle obtained by correcting the reference advance amount according to the operating conditions such as the engine speed, the load, the change amount of the load, the cooling water temperature, etc. Ignition is performed with a value, and ignition timing control such as using a fixed advance value is performed during a transition period when the amount of change in load exceeds a certain value.

By the way, during the 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 cylinder deactivated cylinders may be stopped to perform the cylinder deactivated operation. Internal combustion engines equipped with a stop mechanism are known.
When the control means for controlling the valve stop mechanism of this kind of internal combustion engine enters into the set operating range based on various operating information, the opening / closing operation of the intake / exhaust valves of the deactivated cylinders is stopped and the fuel to the deactivated cylinders is stopped in the operating range. When the supply is stopped and the set operating range is exited, the opening / closing operation of the intake / exhaust valves of the cylinders that are deactivated is returned to the normal state, and the fuel supply to the cylinders that are deactivated is restarted. The ignition device used here continuously performs the ignition process regardless of whether the engine is in the normal operation or the cylinder deactivation operation. In this way, by performing the ignition process continuously even during the cylinder deactivation operation,
The ignition current flowing through the spark plug prevents the plug from becoming dirty, and the ignition process when restarting all cylinders can be performed properly.

[0005]

However, during the cylinder deactivation operation, a negative pressure is created in the combustion chamber of the cylinder deactivated cylinder, and as a result, oil rise easily occurs in the cylinder deactivated cylinder. In particular,
When the cylinder deactivation mode continues for a long time, the ignition plug of the cylinder deactivated cylinder is likely to smolder with oil. In such a cylinder deactivation operation, no problem will occur if the idle ignition is repeated mainly for the purpose of purifying the plug, but one ignition process usually requires 10 to 20 (W / h) electric power, In order to improve fuel efficiency, it is often necessary to stop the ignition process for cylinders that are deactivated. If the ignition process for the cylinders that are inactive is stopped with the main purpose of suppressing unnecessary power consumption in such a cylinder-off mode, the spark plugs of the cylinders that are inactive will be misfired due to oil contamination during the operation of all cylinders again. There is a problem that the output is lowered.

An object of the present invention is to restart the ignition processing of a cylinder which is deactivated in order to clean the plug after a time point when it is considered that the decontamination mode has continued for a predetermined time or more and the contamination of the spark plug is excessively advanced. It is an object of the present invention to provide an ignition control device for an internal combustion engine with a valve stop mechanism capable of performing the above.

[0007]

In order to achieve the above object, the present invention provides an internal combustion engine having a cylinder deactivated cylinder in which at least one of intake and exhaust valves is stopped by valve stopping means during operation in the cylinder deactivated operation mode. Of the cylinder deactivated cylinder group and the constantly operating cylinder group, which are independent of each other, and the ignition control means of the internal combustion engine obtains the ignition timing of both groups according to the operating conditions to perform group ignition of the both ignition drive means. An ignition timing control device for an internal combustion engine with a valve stop mechanism for performing control, wherein a cylinder deactivation duration in the cylinder deactivation operation mode is counted by a cylinder deactivation timer, and the ignition control means is deactivated by the cylinder deactivation timer. When the duration exceeds the set time, the ignition processing in the cylinder deactivation mode is switched to the all cylinder mode.

[0008]

The cylinder deactivation duration in the cylinder deactivation operation mode is counted by the cylinder deactivation timer, and when the ignition control means exceeds the set duration by the cylinder deactivation timer, the ignition process in the cylinder deactivation mode is performed. Is switched to the all cylinders mode, so when the set time, which is considered to be excessively contaminated by the spark plugs of the cylinders that have deactivated, elapses, all the cylinders will be driven for ignition, and the ignition plugs of the cylinders that have deactivated cylinders will be idled. , The dirt can be prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ignition control device for an internal combustion engine with a valve stop mechanism shown in FIG. 1 is installed in an in-line four-cylinder internal combustion engine (hereinafter simply referred to as engine 1). Cylinder head 2 of this engine 1
Each of the cylinders is formed with an end portion of an intake passage and an exhaust passage (not shown) that can communicate with each cylinder, and each passage 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 air supply cam 5 and an exhaust cam 6 via respective rocker arms 3a, 3b, 4a and 4b. Here, each rocker arm 3a, 3b, 4a, 4b is pivotally supported by the intake / exhaust rocker shafts 7, 8, and the air supply cam 5 and the exhaust cam 6 are integrally formed on 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 side (not shown) via a timing belt 13 so that 1 / th of engine rotation is achieved.
It is configured to rotate the cam shaft 9 at a rotation speed of 2. Note that reference numerals 18, 19, and 20 in FIG. 1 indicate bearings that support the respective shafts.

In FIG. 1, the second as a constantly operating cylinder
Each rocker arm 3 of the cylinder (# 2) and the third cylinder (# 3)
b and 4b can always open and close the intake and exhaust valves, and the rocker arms 3a and 4a that oppose the first cylinder (# 1) and the fourth cylinder (# 4) as deactivated cylinders can stop the opening and closing operation of the intake and exhaust valves at a predetermined time. A valve stop mechanism M is attached. It is well known that the valve stop mechanism M in this case moves the valve pressing piece (not shown) on each rocker arm 3a, 4a between the valve opposing position and the retracted position by means of the hydraulic pressure switching means to make the valve pressing operation of the rocker arm idle when the valve is stopped. Take the configuration of. It should be noted that hydraulic oil is supplied from the hydraulic circuit 23 to the hydraulic pressure switching means of the valve stop mechanism M here. This hydraulic circuit 23 receives the pressure oil supplied to and discharged from the valve stop mechanism M from the hydraulic pressure supply means 22 side via the cylinder deactivation solenoid valve 21. Hydraulic pressure supply means 2
2 comprises a hydraulic pump and an oil tank as shown. The cylinder shut-off solenoid valve 21 is a three-way valve, which supplies pressure oil to each valve stop mechanism M when it is on, switches the valve mechanism M to a valve stop and holds it, and eliminates pressure oil of each valve stop mechanism M when it is off. Then, the mechanism M is switched to the valve drive and held, and is driven and controlled by an engine control unit 24 described later.

Further, an injector 25 for injecting fuel to an intake port (not shown) of each cylinder is mounted on the cylinder head 2 of FIG. 1, and each injector has a fuel supply source 27 for supplying the fuel whose constant pressure is adjusted by the fuel pressure adjusting means 26. received,
The injection drive control is performed by the engine control unit 2
Made by four. Further, the cylinder head 2 of FIG. 1 is equipped with an ignition plug 14 for each cylinder. Particularly, both plugs 14 of the constantly operating cylinders # 2 and # 3 are connected together to form an ignition coil as a single ignition drive means. 37 ', a power transistor 38', and a drive circuit 34, and the plugs 14 of the deactivated 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 is connected. Both drive circuits 34,
Reference numeral 35 is connected together to each output circuit 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 are respectively connected to the deactivated cylinders # 1 and # 4 group and the constantly operating cylinders # 2 and # 3 group, and both of them are the reference signal (crank angle φo) and the crank angle signal (1 ° or It is driven by a pulse of a unit of 2 ° (Δθ). In FIG. 2, the cylinders of deactivated cylinders # 1 and # 4 are shown, and the cylinders of constant operation cylinders # 2 and # 3 are omitted. Here, the reference signal ψo is output to the one-shot circuit B, and in the steady operation, the one-shot circuit B is triggered by the reference signal ψo (off-on) of ψo before top dead center (for example, 75 °) to generate the crank angle signal Δθ. It is configured to output the energization start signal after counting (a pulse of a unit of 1 ° or 2 °) for a predetermined number (delay time t1 corresponding to (φo−φt) reaching the ignition timing) (Fig. 3). In this case, the target ignition timing ψt will be described later with reference to FIG.
It is obtained in step a5 of the flowchart.

The one-shot circuit A is triggered by the energization start signal, and is configured to count a predetermined number of crank angle signals corresponding to the dwell angle and output an ignition signal. The flip-flops F and F are set by the energization start signal from the one-shot circuit B and reset by the ignition signal from the one-shot circuit A. Further, the drive circuit 35 turns on the power transistor 38 by the output signal of the flip-flop 7 when the flip-flop 7 is in the set state, and causes the current to flow to the ignition coil 37. The ignition coil 37 produces a high voltage current on the secondary side when the power transistor 38 is turned off, and this current is generated by the cylinder deactivated cylinder #.
This is transmitted to both spark plugs 14 of # 1 and # 4, and the deactivated cylinder group is ignited.

Similarly, the output circuit 36 'of the constantly operating cylinders # 2, # 3 is also constructed so that the secondary high-voltage current of the ignition coil 37' at the target ignition timing ψt causes the constantly operating cylinder # 2.
It is supplied to both spark plugs 14 of # 3 and the group ignition of the constantly operating cylinders is performed. Note that FIG. 4 shows an example of group ignition timings of all cylinders # 1, # 2, # 3, and # 4 in the all cylinder operation mode. Here, the ignition timings of both groups are alternated for each group while maintaining a crank angle of 180 °. On the other hand, in the cylinder deactivated operation mode, as described later, the cylinder deactivated cylinders # 1, # 4
Timely regulate the group ignition process of.

Engine control unit (ECU)
A main part 24 is constituted by a microcomputer, and performs well-known control processing such as control of fuel supply to the engine 1 and also performs ignition control and cylinder deactivation control. Moreover, EC
U24 has a function as an ignition control means, that is, the ignition timings of both groups are obtained according to the operating conditions of the internal combustion engine,
Group ignition control of both ignition drive means is performed, and in particular, the cylinder deactivation duration Tn in the cylinder deactivation operation mode is determined by the cylinder deactivation timer TIM.
1 is counted, and the cylinder deactivation duration Tn is the set time T
When the number exceeds 2, the ignition processing in the cylinder deactivation mode is switched to the all cylinders mode.

In the ECU 24, the engine speed sensor 30 indicates the number of revolutions Ne of the engine 1, the air flow sensor 31 indicates the intake air amount A information, and the vehicle speed sensor 32 indicates the vehicle speed Sv.
From the crank angle sensor 33, the unit crank angle signal Δθ
However, the reference signal ψo (which is issued at every crank angle of 180 ° here) is fetched from the cylinder discrimination sensor 36, and various operation information such as throttle opening information and water temperature are fetched. 5 to 7 show flowcharts of a control program of the ECU 24 used in the ignition timing control device for the internal combustion engine with the valve stop mechanism according to the embodiment of the present invention. The ECU 24 enters control in the main routine by keying on a main switch (not shown).

Here, first, each function is checked, an initial function set such as an initial value set is made, and subsequently, various engine operation information is read. After that, the process proceeds to the cylinder deactivation control process of step a3. As the cylinder deactivation control processing here, a well-known cylinder deactivation control is executed. For example, if the current rotation speed is lower than the cylinder deactivation rotation speed and the vehicle is traveling at a constant speed in the medium to low load operating range, the cylinder deactivation mode is executed. Is selected, and a cylinder deactivation time timer T described later
IM1 is reset to 0. Further, the ECU 24 turns on the cylinder deactivation electromagnetic valve 21 to switch the valve stop mechanism M to perform a cylinder deactivation switching process for the first and fourth cylinders # 1 and # 4. Is selected, the cylinder deactivation solenoid valve 21 is turned off, the valve stop mechanism M is switched again, and the cylinder deactivation of the first and fourth cylinders # 1 and # 4 is released to switch to the all cylinder mode. To do. When the cylinder deactivation operation mode is entered, the command is issued by switching the cylinder deactivation flag ICFLG.

In the ignition timing calculation processing of step a4,
A known process is performed in which the reference ignition timing is corrected by the water temperature of the engine, the engine speed, the load, etc. to obtain the target ignition timing ψt, and the dwell angle at each ignition process is calculated based on the engine speed Ne. When step a5 is reached, other control of the engine, for example, the calculation processing of the fuel injection amount and the like are executed, the processing of the control cycle is ended, and the routine returns.
In the fuel supply control performed by the ECU 24 here, for example, a basic fuel pulse width based on the intake air amount is calculated, and this is multiplied by an air-fuel ratio and other correction factors to determine the injector drive time, and when the cylinder is idle (described later). Injector stop command)
Are cylinders # 2 and # 3 that are in constant operation except cylinders # 1 and # 4
The well-known injector drive control processing of driving the injectors 25 of all the cylinders and driving the injectors 25 of all the cylinders when all cylinders are in operation is performed.

An interrupt is issued during the execution of such a main routine, and the ignition control of FIG. 6 and the cylinder deactivation regulation process of FIG. 7 are executed. That is, the ignition control of FIG. 6 is executed based on the reference signal ψo changing from OFF to ON every time each cylinder reaches 75 ° (75 ° BTDC) before top dead center (crank angle 180 °). At step b1 here, ON / OFF information of the cylinder deactivation flag ICFLG, cylinder discrimination information (determined from the reference signal ψo), and the like are fetched, and it is determined at step b2 whether ICFLG is on. Only when it is on and at step b3, it is determined that this time is the ignition timing cycle of the deactivated cylinders # 1, # 4, the process proceeds to step b6. If not, the process proceeds to step b4.

In step b4, the two and three cylinders # 2 and # 3 are
Cylinder discrimination information (reference signal ψ
(determination from o)), and in the case of the # 2 and # 3 groups of the two and three cylinders, the process proceeds to step b5, and otherwise proceeds to step b7. At step b5, the latest dwell angle is set in the one-shot circuit A of the output circuits 36 of the # 2 and # 3 cylinders # 2 and # 3 groups, and the latest target ignition timing ψt is set in the one-shot circuit B, and the main routine is executed. Return to.
This step b5 is reached during the ignition process of the constantly operating cylinders # 2, # 3 in the all cylinder operation mode or the cylinder deactivation operation mode, and one of the second and third cylinder groups is ignited near the compression top dead center. , The explosion stroke, and the other is ignited in the air near the top dead center of the exhaust gas. Similarly, the crank angle is 180 °
At the time of elapse, at this time, one of the second cylinder and the third cylinder is ignited in the vicinity of the compression top dead center and proceeds to the explosion stroke, and the other is ignited in the air in the vicinity of the exhaust top dead center.

When the ICFLG is turned on by the cylinder deactivation command and the process reaches step b3 and it is determined that this time is the ignition timing cycle of the cylinder deactivated cylinders # 1 and # 4, the process proceeds to step b7. In steps b7 and b8, a preset constant dwell angle is set in the one-shot circuit A of the output circuits 36 of the 1,4 cylinders # 1 and # 4 groups, and the preset constant ignition timing ψt1 is set in the one-shot circuit B. Set and return to the main routine.

On the other hand, the cylinder deactivation regulation process of FIG. 7 is executed based on the input of crank pulses at each predetermined crank angle. At step r1 here, it is judged based on the ON / OFF information of the cylinder deactivation flag ICFLG whether or not it is the cylinder deactivation mode at present, and the process returns in the cylinder deactivation mode. If not, the routine proceeds to step r2.
Here, it is determined that the vehicle is stopped, and if the vehicle is stopped, the process goes to step r3. If not, the process proceeds to step r8 and the cylinder deactivation prohibition flag KF.
It is determined whether LG is on, and if KFLG = 0 and cylinder deactivation is not prohibited, step r10 is directly executed. If cylinder deactivation KFLG = 1 and cylinder deactivation is canceled KFLG = 0, then step r is performed.
Go to 10. In this step r10, a cylinder deactivation time timer TIM1 which will be described later is initialized and the process returns to the main routine.

On the other hand, when step r3 is reached while the vehicle is stopped,
After the engine stall, it is determined whether or not a predetermined time has elapsed, before the elapse, the process proceeds to step r8, and then to step r4, and subsequently it is determined whether or not the water temperature Wt exceeds the warm-up determination value T1.
Before warming up, the routine proceeds to step r8, and upon completion, the routine proceeds to step r5. At step r5, it is determined whether or not the well-known throttle opening adjustment mode (SAS mode) is executed. If it is executed, the routine proceeds to step r8, and if not, the routine proceeds to step r6. Step r6 is reached when it is possible to hold the cylinder deactivation mode as a result of the determination in steps r2 to r5, and here, the cylinder deactivation duration time T of the cylinder deactivation time timer TIM1 is reached.
It is determined whether or not n exceeds the set time T2, the process proceeds to step r1 before the elapse and to step r7 when the elapses. The set time T2 here is set in advance as a time when it is considered that the spark plugs 14 of the 1st and 4th cylinders # 1 and # 4 during cylinder deactivation are excessively contaminated.

When the cylinder deactivation continuation time Tn exceeds the set time T2 and reaches step r7, the cylinder deactivation prohibition process is forcibly performed, that is, the cylinder deactivation prohibition flag KFLG is turned on, and the cylinder deactivation flag is forcibly set to ICFLG =. It processes to 0 and returns to the main routine. The command of the cylinder deactivation flag ICFLG = 0 by the process of step r7 is taken in at step b2 during the ignition control described above, and the process can be performed so as to forcibly advance the subsequent step to b4. 3 groups and 1 and 4 cylinders # 1 and # 4 groups can be driven alternately, dirt on plugs of deactivated cylinders # 1 and # 4 can be removed, and stable ignition operation can always be obtained. It is possible to reliably prevent the output from decreasing.

[0025]

As described above, according to the present invention, the cylinder deactivation continuation time Tn is continuously counted after entering the cylinder deactivation time,
When the cylinder deactivation duration exceeds the set time, the ignition process is forcibly performed in the all cylinder mode, so that the spark plug can be prevented from becoming dirty, and the spark plug oil can be prevented from becoming dirty in the cylinder that is deactivated. It is possible to obtain the ignition operation described above, and it is possible to reliably prevent a decrease in output due to engine misfire.

[Brief description of drawings]

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

FIG. 2 is a block diagram of essential parts of an ignition drive means and an ignition control means in the ignition timing control device of FIG.

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

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

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

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

7 is a flowchart of a cylinder deactivation restriction processing routine performed by an ECU in the apparatus of FIG.

[Explanation of symbols]

 1 Engine 2 Cylinder Head 14 Spark Plug 24 ECU 25 Injector M Valve Stopping Mechanism ψt Target Ignition Timing ψo Reference Signal # 2 Always Operated Cylinder # 3 Always Operated Cylinder # 1 Inactive Cylinder # 4 Inactive Cylinder KFLG Inactive Disable Flag ICFLG Inactive Cylinder flag Tn Cylinder deactivation time TIM1 Cylinder deactivation time timer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location F02P 9/00 304 H

Claims (1)

[Claims] 1. A cylinder deactivated by which at least one of the intake and exhaust valves is stopped by valve stop means during operation in a cylinder deactivated operation mode, and both cylinder deactivated cylinder groups and constant operation cylinder groups of the internal combustion engine which are independent of each other. Equipped with drive 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 timings of both groups according to operating conditions and performs group ignition control of the both ignition drive means. The cylinder deactivation duration in the operation mode is counted by the cylinder deactivation timer, and the ignition control means switches the ignition processing in the cylinder deactivation mode to the all cylinder mode when the cylinder deactivation duration of the cylinder deactivation timer exceeds the set time. An ignition control device for an internal combustion engine with a valve stop mechanism, characterized in that: