JP2697531B2 - 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 relates to a cylinder-stopping system in which an intake / exhaust valve of a cylinder-stop cylinder which is set for an internal combustion engine is stopped in a timely manner to stop the cylinder-stop cylinder, and the other always-operating cylinders are driven. The present invention relates to an ignition control device for an internal combustion engine equipped with a valve stop mechanism that is mounted on an internal combustion engine that can operate in an operation mode and that determines a target ignition timing according to operating conditions of the engine and performs an ignition process at the target ignition timing.

[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 dwell angle, which represents the ignition timing and the energization time to the ignition coil by the crank angle,
The current to the ignition coil is turned on and off by a switching transistor (power transistor). 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 timely reduce output and reduce fuel consumption, 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.
The operation mode switching control means for controlling the valve stop mechanism of this kind of internal combustion engine stops the opening / closing operation of the intake / exhaust valves of the cylinders in the cylinder stop and the cylinders in the cylinder stop within the operation range when the engine enters the set operation range based on various operation information. When the supply of fuel to the cylinder is stopped and the set operating range is left, the opening / closing operation of the intake / exhaust valve of the cylinder closed cylinder is returned to a normal state, and the fuel supply to the cylinder closed cylinder is restarted. In an internal combustion engine with a valve stop mechanism of this type, during an idling operation of the engine, an advance amount that can eliminate a rotational deviation between the target rotational speed and the actual rotational speed in order to maintain the idle rotational speed at a set value is calculated. The idling speed is stabilized by driving the ignition drive means at the target ignition timing that captures the angular amount.

[0004]

However, in an internal combustion engine with a valve stop mechanism, as shown in FIG. 10, the change rate of the engine speed with respect to the change amount of the ignition timing during the idling operation is different between the full cylinder mode and the closed cylinder mode. Different. In particular, the change in the engine speed with respect to the change in the ignition timing is smaller in the cylinder-stop mode than in the all-cylinder mode, and the change in the engine speed reaches a plateau in the advance-side region e1. In other words, the ignition timing correction amount Δ for the rotation deviation ΔNe
θ is sufficiently larger in the closed cylinder mode than in the all cylinder mode.

However, conventionally, in the process of correcting the variation of the idling speed during the idling operation of the internal combustion engine with the valve stop mechanism, a fixed ignition timing correction gain Kinj (= Δθ / ΔNe) is used to calculate the ignition timing correction amount Δθ per deviation rotational speed. For this reason, during idle operation, the absolute value of the ignition timing correction amount per unit rotation deviation is too small in the cylinder-stop mode compared to the all-cylinder mode, and it is not possible to sufficiently correct the rotational deviation. Variations in idle speed due to timing adjustment could not be corrected with good responsiveness, which was a problem. SUMMARY OF THE INVENTION An object of the present invention is to provide an ignition control device for an internal combustion engine with a valve stop mechanism that can stabilize the idle speed with good responsiveness by correcting the ignition timing.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention switches and controls a valve stop mechanism mounted on a valve train of an internal combustion engine to selectively operate in a full cylinder mode or a closed cylinder mode. Operating mode switching control means for driving each cylinder; basic ignition timing calculating means for calculating basic ignition timing according to the load signal of the engine and the engine speed signal of the engine; and smoothing for smoothing the engine speed. Deviation rotation speed calculating means for calculating a deviation rotation speed which is a difference between the converted rotation speed and the actual engine rotation speed, and fetching the operation mode information during idling operation of the engine and correcting ignition timing according to the deviation rotation speed The amount is set larger in the cylinder-stop mode than in the all-cylinder mode, and the advance-side ignition timing correction amount in the cylinder-stop mode is larger in absolute value than the retard-side ignition timing correction amount. A constant ignition timing correction amount calculating means,
Ignition timing calculation means for correcting the basic ignition timing with an ignition timing correction amount corresponding to each operation mode to calculate a target ignition timing, and driving ignition drive means for each cylinder of the internal combustion engine to the target ignition timing. And ignition control means.

[0007]

[Function] The ignition timing correction amount calculating means fetches each operation mode information corresponding to the all cylinder mode and the cylinder deactivation mode, and sets the ignition timing correction amount corresponding to the deviation rotation speed to be larger in the cylinder deactivation mode than in the full cylinder mode. The ignition timing calculation means corrects the basic ignition timing with an ignition timing correction amount corresponding to each operation mode to calculate a target ignition timing, and the ignition control means drives the ignition drive means of each cylinder of the internal combustion engine to the target ignition timing. Therefore, the ignition timing correction amount necessary to cancel the deviation rotation speed is obtained as an accurate value for each operation mode. Can be corrected.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The engine ignition timing control device shown in FIG. 1 is mounted on an in-line four-cylinder engine (hereinafter simply referred to as engine E) having an operation mode switching mechanism. The intake passage 1 of the engine E includes an intake branch pipe 6, a surge tank 9 connected thereto, an intake pipe 7 integrated with the tank, and an air cleaner (not shown). The intake pipe 7 pivotally supports the throttle valve 2 therein, and the shaft 201 of the throttle valve 2 is connected to the throttle lever 3 outside the intake passage 1. The throttle lever 3 is connected to the throttle lever 3 via a throttle lever 3 linked to an accelerator pedal (not shown) so as to rotate the throttle valve 2 in a counterclockwise direction in FIG. By a return spring (not shown) for urging this in the closing direction,
When the pulling force of the accelerator cable is reduced, it closes. The throttle valve 2 is provided with a throttle opening sensor 8 for outputting information on the opening of the throttle valve.

On the other hand, an idle speed control (ISC) valve 4 for idle control is provided on an intake bypass 101 which bypasses the throttle valve 2, and the valve 4 is provided with a spring 40.
1 and is driven by a stepper motor 5. Reference numeral 16 denotes a first idle air valve that automatically performs warm-up correction during idling according to the cooling water temperature. Further, the intake passage 1 is provided with an intake air temperature sensor 14 for outputting information on the intake air temperature Ta, a water temperature sensor 11 for detecting a cooling water temperature as a warm-up temperature of the engine, and detects the engine speed by an ignition pulse. An engine rotation sensor 12 is provided, a battery sensor 20 for detecting a battery voltage VB is provided, and a knock sensor 21 for outputting knock information is provided. Further, the surge tank 9 is provided with a negative pressure sensor 10 for outputting information on the intake pipe pressure Pb.

In the cylinder head 13 of the engine E, an intake passage and an exhaust passage which can communicate with each cylinder are formed, respectively.
Each channel is opened and closed by an intake valve and an exhaust valve (not shown). The valve train shown in FIG. 1 includes a valve stop mechanism. The valve stop mechanism selectively drives a supply / exhaust valve (not shown) with a low speed cam and a high speed cam (not shown) to operate in a low speed mode M-1 and a high speed mode M-.
The first cylinder (# 1) and the fourth cylinder (# 1) as the cylinders other than the second cylinder (# 2) and the third cylinder (# 3) as the always operating cylinders can be operated in a timely manner. 4) The respective intake / exhaust valves are stopped to enable operation in the cylinder-stop mode M-3. That is, the valve stop mechanism of this valve train can be operated by a hydraulic low-speed switching mechanism K1 capable of stopping the operation of the low-speed cam of the suction and discharge valve at a predetermined time on each rocker arm (not shown), and stopping the operation of the high-speed cam of the suction and discharge valve at a predetermined time. And a simple hydraulic high-speed switching mechanism K2. Here, each switching mechanism K1,
K2 adopts a well-known configuration in which the engagement / disengagement of the rocker arm (not shown) and the rocker shaft is switched by moving an engagement pin (not shown) by a hydraulic cylinder, and the engagement / disengagement of the elevation cam and the rocker arm can be selectively performed.

The low-speed switching mechanism K1 is supplied with pressure oil from the hydraulic circuit 22 via a first electromagnetic valve 26, and the high-speed switching mechanism K2 is supplied from the hydraulic circuit 30 with a second electromagnetic valve 31.
The pressure oil is supplied via. Here, the operation in the low-speed mode M-1 by the low-speed cam is achieved by turning off both the first solenoid valve 23 and the second solenoid valve 31 which are three-way valves, and the operation in the high-speed mode M-2 by the high-speed cam is performed in the first mode. Solenoid valve 23 and second solenoid valve 3
1 are turned on, and the operation in the cylinder-stop mode M-3 is achieved when the first solenoid valve 23 is turned on and the second solenoid valve 31 is turned off. The drive of these solenoid valves 26 and 31 is controlled by an engine control unit (ECU) 15 described later. Further, an injector 17 for injecting fuel into each cylinder is mounted on the cylinder head 13 in FIG. 1, and each injector receives the fuel whose pressure has been adjusted by the fuel pressure adjusting means 18 from a fuel supply source 19. ECU1
5 is performed.

Further, an ignition plug 23 is mounted on the cylinder head 13 of FIG. 1 for each cylinder. In particular, both plugs 23 of the constantly operating cylinders # 2 and # 3 are connected together to form a single ignition drive circuit. Connected to the igniter 24 of the cylinder
Both the plugs 1 and # 4 are connected together and the igniter 2
5 is connected. Here, the ignition plug 23 and the ignition drive circuit constitute ignition drive means. Further, the ignition drive circuit includes a pair of timing control circuits 36 (only one is shown in FIG. 2) in the ECU 15 and a pair of igniters 24 and 25.
Open / close drive circuits 241, 251. Each of the open / close drive circuits 241 and 251 is connected to each power transistor 38 for controlling the open / close timing and the energizing time, and each of the power transistors 38 and 38 is connected to each ignition coil 37.

The timing control circuit 36 controls the closed cylinder # 1,
The # 4 group and the always-operated cylinders # 2 and # 3 are provided respectively for the reference signal (θco in crank angle) of the crank angle sensor 34 and the crank angle signal (1 ° or 2 ° (1 ° or 2 °) of the unit crank angle sensor 33). Δθc), and FIG.
The figures for the # 4 group are shown, and those for the constantly operating cylinders # 2 and # 3 are omitted. Here, the reference signal θco is output to the one-shot circuit B. During a steady operation, the one-shot circuit B is triggered by a reference signal (off-on) of θco (for example, 75 °) before the top dead center, and the crank angle signal (1
An energization start signal is output after counting a predetermined number of pulses (in units of ° or 2 °) (delay time t1 corresponding to the ignition timing θco−θadv) (see FIG. 3). In this case, the target ignition timing θadv is obtained in step p12 of the flowchart of FIG. The one-shot circuit A is triggered by the energization start signal, and counts a predetermined number of crank angle signals corresponding to the dwell angle (determined by the dwell angle map in FIG. 6) θd and outputs 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, the opening / closing drive circuit 251 turns on the power transistor 38 for the set time when the flip-flop FF is set, 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, and this current is transmitted to both the spark plugs 23 of the cylinders # 1 and # 4, thereby igniting the cylinder group. . Similarly, a timing control circuit (not shown) for the constantly operating cylinders # 2 and # 3 is also configured, and the secondary side high voltage of the ignition coil 37 is set to the target ignition timing θadv according to the driving of the open / close drive circuit 241 and the power transistor 38. The current is supplied to the spark plugs 23 of the constantly operating cylinders # 2 and # 3, and the group ignition of the constantly operating cylinders is performed. It should be noted that the cylinders in the closed cylinders # 1, # 1
The group ignition timing of No. 4 and the group ignition of the constantly operating cylinders # 2 and # 3 are alternately performed for each group while maintaining an interval of approximately 180 ° crank angle.

Engine control unit (ECU)
Reference numeral 15 denotes a main part formed by a microcomputer, which executes a main routine, which will be described later, according to operation information of the engine E, performs well-known control processing such as well-known fuel injection amount control, and performs an ignition timing calculation routine and ignition control. Perform each control in the routine. The ECU 15 includes a water temperature sensor 11, a throttle opening sensor 8, and an intake air temperature sensor 14.
The cooling water temperature Tw, the throttle opening degree θs, the intake air temperature Ta, the battery voltage VB, and the knock signal Kn are detected by the battery sensor 20 and the knock sensor 21 and stored in a predetermined data storage area. Further, the ECU 15 calculates a deviation rotation speed ΔNe, which is a difference between the smoothed rotation speed Ne1n obtained by smoothing the engine rotation speed and the actual engine rotation speed Nen, as a deviation rotation speed calculation means. During idle operation of the engine, the operation mode signals (M-1, M-2, M-3) are taken in, and the ignition timing correction amount Δθ according to the deviation rotation speed ΔNe is set to be larger in the closed cylinder mode than in the full cylinder mode, As a basic ignition timing calculating means, a basic ignition timing θb is calculated in accordance with an intake pipe negative pressure Pb, which is a load signal of the engine, and an engine speed Ne, and the basic ignition timing θb is corrected by an ignition timing correction amount Δ in accordance with each operation mode.
means for calculating a target ignition timing θadv by correcting with θ, and target ignition timing θadv as ignition control means.
Has a function of driving an ignition plug 23 and an ignition drive circuit (timing control circuit 36 and igniters 24 and 25) as ignition drive means for each cylinder of the internal combustion engine.

Here, an ignition control device for an internal combustion engine with a valve stop mechanism according to one embodiment of the present invention will be described with reference to control programs shown in FIGS. The ECU 15 starts the control in the main routine by turning on a main switch (not shown). Here, first, each function is checked, an initial function set such as an initial value set is performed, and then, various operation information of the engine is read, and then the process proceeds to step s2.
Then, a fuel cut zone is determined from an operating range map (not shown) that calculates an operating range from the engine speed N and the intake pipe negative pressure Pb. In the fuel cut range, the process proceeds to step s4, where the air-fuel ratio feedback FBFLG is cleared, and the fuel cut is determined. FCFLG is set to 1 and the process returns.

On the other hand, if it is determined in step s2 that the fuel cut is not in the fuel cut range and the process reaches step s3, the fuel cut FCFLG is cleared, and it is determined whether the air-fuel ratio feedback condition is satisfied. At the time of or before the completion of warm-up, at step s7,
Air-fuel ratio correction coefficient KM according to current operation information (Pb, Ne)
The warm-up increase correction coefficient Ka corresponding to the AP and the cooling water temperature Tw is calculated from an appropriate warm-up increase correction coefficient calculation map, these values are stored in the storage area of the address KAF, and the process proceeds to step s10. If the air-fuel ratio feedback condition is satisfied from step s6, a target air-fuel ratio is calculated according to the current operation information (Pb, Ne), and a fuel amount correction coefficient _KFB that can achieve the air-fuel ratio is calculated. In step s9, the address K
Store the fuel amount correction coefficient K _FB in the storage area of the AF, it reaches step s10. Here, the other fuel injection pulse width correction coefficient KDT and the correction value TD of the dead time of the fuel injection valve are set in accordance with the operating conditions, and further, each correction coefficient used for calculating the target ignition timing θadv is calculated. Here, the correction value is calculated as a water temperature correction value θwt to be advanced in accordance with a decrease in the water temperature, an acceleration retard −θacc corresponding to the differential value Δθs corresponding to the differential value Δθs, and the advance in accordance with a decrease in the intake air temperature. There is an intake air temperature correction value θat to be turned, a knock retardation −θk value according to an increase in the knock signal Kn, a battery correction value tb for increasing the energization time according to a decrease in the battery voltage VB, and a dwell angle corresponding to the ignition energization time. The dwell angle calculation map in FIG. 6 is calculated so that θd increases in accordance with the engine speed Ne.

Further, upon reaching step s11, a well-known cylinder operation switching process is executed. For example, the current operation mode is detected from the on / off state of the low / high solenoid valves 26, 31.
Based on the engine operation information, in particular, the engine speed Ne and the shaft torque (calculated by another routine from Pb and Ne) Te, it is determined based on each threshold Ne2 whether or not the engine is in the cylinder deactivated operation range A1 as shown in FIG. The cylinder-stop mode is set, and if the cylinder-stop condition is not satisfied, the low-speed mode is set if the engine speed Ne is smaller than Ne1 (see FIG. 5), and the high-speed mode is set otherwise. In the cylinder-stop mode, the first solenoid valve 2
6 is turned on to perform a cylinder switching process for the first and fourth cylinders # 1 and # 4. In the low-speed mode M-1, both solenoid valves 26 and
In the high-speed mode M-2, both solenoid valves 26 and 31 are turned on to drive all cylinders in the high-speed mode. When the cylinder-stop operation mode is entered, the command is issued by switching the cylinder-stop flag ICFLG. Thereafter, control is performed in other main routines such as a fuel supply control process, and the routine returns.

Here, the fuel supply control performed in the middle of the main routine is performed, for example, by calculating a basic fuel pulse width based on the intake air amount, multiplying the basic fuel pulse width by an air-fuel ratio and other correction coefficients to determine an injector driving time, and During cylinder operation (injection stop command to be described later), the injectors 17 of only the always-operated cylinders # 2 and # 3 except the cylinders # 1 and # 4 are driven, and the injectors 17 of all cylinders are driven during all-cylinder operation. A well-known injector drive control process is performed. During the execution of such a main routine, FIG.
And the ignition control of FIG. 9 is executed.

That is, in the ignition timing calculation routine of FIG. 8, each time each cylinder reaches 75 ° (75 ° BTDC) before top dead center (crank angle 180 °), the reference signal θc is switched from OFF to ON.
It is executed based on the change of o. In step p1, the intake pipe negative pressure Pb and the engine speed N are determined based on the detection signals of the negative pressure sensor 10 and the engine speed sensor 12.
is calculated, and further, a basic ignition timing θb corresponding to the current intake pipe negative pressure Pb and the engine speed Ne is calculated from a preset basic ignition timing calculation map. Thereafter, the process proceeds to step p3 where the engine speed N
It is determined whether or not en is lower than an idle determination value Nea which is a set value. If it is higher, step p4 is reached and the non-idle correction gain Kinj is set to a set value (for example, zero in this case).
And proceeds to step p9.

On the other hand, if it is determined that the engine is idling at step p3 and the process reaches step p5, first, the current engine speed Nen is taken into the smoothed speed Ne1 (n-1) up to the previous time at a predetermined take-in ratio α. The current smoothed rotation speed Ne1n is newly calculated, and subsequently, the smoothed rotation speed Ne1n is calculated.
The difference rotational speed ΔNe, which is the difference between 1n and the current engine rotational speed Nen, is calculated according to equation (2) (see FIG. 4). Ne1n = Ne1 (n-1) .times..alpha. + (1-.alpha.). Times.Nen (1) .DELTA.Ne = Ne1n-Nen (2) Thereafter, the process proceeds to step p6. Cylinder rest mode M-
In the low speed and high speed modes (M-1, M-2) when the cylinders are not closed, the process proceeds to step p8, where the correction gain Kinja (set value) for all cylinders is selected, and step p9 is performed. Proceed to.

On the other hand, if it is determined in step p6 that the cylinder has been closed, the operation proceeds to step p7. Here, the cylinder-stop correction gain K
Select injb and proceed to step p9. Note that the correction gain Kinja at the time of all cylinders and the correction gain Ki at the time of cylinder deactivation are used here.
njb is set according to the drive data of each engine, and is set as appropriate based on, for example, an ignition timing-engine speed characteristic diagram during idling of FIG. Here, in particular, the correction gain Kinja at the time of all cylinders (= Δθa / ΔN)
e), the advanced angle correction gain Kinjb (= Δθ
b / ΔNe) is set to a sufficiently large absolute value.

In this way, in correcting the deviation of the engine speed during idling operation, the correction range of the ignition timing with respect to the rotational deviation at the time of cylinder deactivation is made relatively large as compared with the case of all cylinders, and the advance side (Kinjb) or the retard angle Side (-Kinj
b) to prevent the responsiveness of the correction of the idling speed by the ignition timing correction from being lowered, and to correct the variation of the idling speed at the time of cylinder deactivation with good responsiveness.

In step p9, the current correction gain Kin
The correction gain Kinja, Kin selected this time as j
The ignition timing correction amount Δθ is calculated by multiplying this Kinj by the rotation deviation ΔNe, and the process proceeds to step p10.

At step p10, the basic ignition timing θb, the water temperature correction value θwt, the acceleration retardation-θac
c, an intake air temperature correction value θa that is advanced according to a decrease in intake air temperature
t, the ignition timing correction amount Δθ is fetched, and then the target ignition timing is calculated by the following equation (3). .theta.adv = .theta.b + .theta.wt + .theta.at + Kinj.times.Ne-.theta.acc (3) Thereafter, in step p11, the target ignition timing .theta.adv by the knock retard-.theta.
Is retarded, and in step p12, the storage area of the previous smoothed rotation speed Ne1 (n-1) is stored in the current smoothed rotation speed Ne1n.
And return to the main routine. Note that the knock retard map is set in advance. The ignition control routine of FIG. 9 is performed at 75 ° before the top dead center in the middle of the main routine.
(75 ° BTDC) (Crank angle 180 °)
The main routine is interrupted and executed based on the change of the reference signal θco from off to on. In step q1, predetermined data is fetched. In step q2, the latest target ignition timing θadv and the latest dwell angle θd are set in each timing control circuit 36, and the process returns to the main routine.

Here, the group ignition of the always operating cylinders # 2 and # 3 and the group ignition of the cylinders # 1 and # 4 are performed by driving the igniters 24 and 25, and each igniter is driven every time the crank angle elapses 180 °. Then, the ignition process is alternately performed with one of the groups near the compression top dead center and the other near the exhaust top dead center.

The injector driving process is performed during the main routine. Here, the calculated intake air amount A / N is taken in accordance with the in-cylinder pressure Pb and the engine speed Ne, the basic fuel pulse width Tf is calculated from the intake air amount A / N, and the air / fuel ratio taken in from the main routine side. Correction coefficient K
The target injector drive time is calculated based on the AF, the atmospheric temperature and atmospheric pressure correction coefficient KDT, the injector operation delay correction value TD, and the like, and the target fuel pulse width Tinj is supplied to the driver for driving all the injectors 17 of the first to fourth cylinders during all cylinder operation.
The known process of setting the target fuel pulse width Tinj to the driver for driving the injectors 17 of only the two and three cylinders when the cylinder is closed, triggering each driver and returning is performed.

[0028]

As described above, according to the present invention, when correcting the deviation of the idling speed during the idling operation, the ignition timing correction amount per unit rotation deviation in the cylinder deactivated mode is smaller than that in the all cylinder mode. The absolute value can be set to a large value.This makes it possible to compensate for the low responsiveness at the time of correcting the variation of the idling speed due to the insufficient ignition timing correction amount at the time of cylinder deceleration as in the past, and to increase the idling speed at a high responsiveness. Can be stabilized.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an ignition control device for an internal combustion engine as one embodiment of the present invention.

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

FIG. 3 is a diagram showing a temporal operation of an ignition drive circuit in the ignition timing control device of FIG. 1;

FIG. 4 is a graph showing the variation of the idle speed performed by the ignition timing control device of FIG. 1 and the change of the correction amount of the ignition timing at that time with time.

FIG. 5 is a characteristic diagram of an operating range calculation map of an internal combustion engine equipped with the ignition timing control device of FIG. 1;

FIG. 6 is a characteristic diagram of a dwell angle calculation map used by the ignition timing control device of FIG. 1;

FIG. 7 is a flowchart of a main routine performed by the ignition timing control device of FIG. 1;

FIG. 8 is a flowchart of an ignition timing calculation routine performed by the ignition timing control device of FIG. 1;

FIG. 9 is a flowchart of an ignition control routine performed by the ignition timing control device of FIG. 1;

FIG. 10 is a characteristic diagram of ignition timing-engine speed during idling of the internal combustion engine.

[Explanation of symbols]

 Reference Signs List 2 throttle valve 8 throttle opening sensor 10 intake pipe negative pressure sensor 12 engine rotation sensor 15 ECU 17 injector 23 spark plug 24 igniter 25 igniter 33 unit crank angle sensor 34 crank angle sensor 36 timing control circuit θadv target ignition timing E engine

Claims (1)

(57) [Claims] An operation mode switching control means for switching and controlling a valve stop mechanism mounted on a valve train of an internal combustion engine to selectively drive each cylinder in an all-cylinder mode or a closed-cylinder mode, and a load on the engine. A basic ignition timing calculating means for calculating a basic ignition timing according to the signal and an engine speed signal of the engine; and a deviation speed which is a difference between a smoothed speed obtained by smoothing the engine speed and an actual engine speed. And an ignition timing for taking in the operation mode information during the idling operation of the engine and setting an ignition timing correction amount corresponding to the deviation rotation speed to be larger in the closed cylinder mode than in the full cylinder mode. Correction amount calculation means; ignition timing calculation means for correcting the basic ignition timing with an ignition timing correction amount corresponding to each of the operation modes to calculate a target ignition timing; Ignition control device of the valve stop mechanism with an internal combustion engine, characterized in that the ignition timing and a spark control means for driving the ignition driving means of each cylinder of the internal combustion engine.