JP2002276520A - Engine ignition control device - Google Patents

Abstract

(57) Abstract: An engine provided with a variable valve timing mechanism has improved ignition timing control accuracy. A valve timing VTCNOW of an intake valve is provided.
(Int) and the valve timing VTCNOW of the exhaust valve
(Exh), the basic correction amount ADVvtcb of the ignition timing is retrieved from the map, and the engine speed Ne is calculated.
And the basic fuel injection amount Tp, the operating state correction coefficient K
tvc is retrieved from the map, and these are multiplied to calculate the VTC correction amount ADVvtc.
The ignition timing is corrected and controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition control device for an engine in which valve timings of an intake valve and an exhaust valve are independently and continuously variably controlled.

[0002]

2. Description of the Related Art In fuel injection control of a vehicle engine, the valve timing (opening / closing timing) of an intake / exhaust valve is continuously changed by changing a rotation phase of a camshaft with respect to a crankshaft to improve driving performance. There is an engine provided with a variable valve timing mechanism for performing variable control (see Japanese Patent Application Laid-Open No. H10-14022).

In an engine equipped with the above-described variable valve timing mechanism, when the valve timing is changed in accordance with a change in the operating state, the valve overlap amount of the intake / exhaust valve changes and the internal EGR amount (residual burned gas amount) ) Changes, the flammability (ignition delay time, etc.) is increased. Therefore, it is necessary to set the engine ignition timing in consideration of the change in flammability due to the change in the valve timing.

Conventionally, the target valve timing of the intake and exhaust valves is basically set according to the operating state (rotational speed and load) of the engine. Therefore, the valve timing of the intake and exhaust valves is also taken into consideration for each operation region. This is done by setting the basic ignition timing. However, in the method of setting the ignition timing for each operation region in consideration of the valve timing of the intake and exhaust valves, the actual valve timing may deviate from the target valve timing due to transient operation or temporary operation fluctuation. . For this reason, in Japanese Unexamined Patent Application Publication No. 9-209895, the ignition timing correction amount is set in accordance with the deviation between the target valve timing and the actual valve timing, and the ignition timing is corrected.

[0005]

However, in the above-mentioned method, in which only one valve timing of the intake and exhaust valves is variably controlled (usually, only the intake valve side is controlled as in the embodiment in the publication), Although it can be easily controlled, it is not practical to control the valve timing of the intake valve and the exhaust valve independently and continuously to obtain higher performance. That is, it is necessary to obtain a deviation between the target valve timing and the actual valve timing for each of the intake valve and the exhaust valve, and to perform an extremely complicated control of setting an ignition timing correction amount for a combination of these deviations. The amount of data storage is enormous.

Further, even when the engine speed and load (fuel injection amount, etc.) are the same, when the target valve timing is to be changed under another condition, for example, the engine temperature, the control is further complicated. Is practically difficult to achieve. The present invention has been made in view of such a conventional problem. In an engine in which the valve timings of an intake valve and an exhaust valve are independently and continuously controlled, the valve timing is relatively easily controlled. It is an object of the present invention to provide an ignition control device for an engine in which the ignition timing is appropriately controlled in response to a change in the ignition timing.

[0007]

SUMMARY OF THE INVENTION Therefore, an invention according to claim 1 is an ignition control device for an engine in which valve timings of an intake valve and an exhaust valve are independently and continuously variably controlled. The valve timing of the exhaust valve is detected, a valve timing correction amount of the engine ignition timing is set based on the detected values, and the ignition is controlled to the ignition timing corrected by the set valve timing correction amount. .

According to the first aspect of the present invention, the actual valve timing of the intake valve and the exhaust valve is detected by a sensor or the like, and the engine timing is determined by searching the map data based on the two detected valve timing values. A valve timing correction amount of the ignition timing is set, and the ignition is controlled to the ignition timing corrected by the correction amount.

With this arrangement, not only when the actual valve timing of the intake valve and the actual valve timing of the exhaust valve coincide with the respective target valve timings, but also when the actual valve timings are deviated by an arbitrary amount from the target valve timings in an arbitrary direction. Optimal ignition timing correction is always performed so as to match the flammability according to the actual valve timing at that time. In addition, even when the target valve timing is set under conditions other than the operation range, the control can be easily performed using the minimum necessary data.

In the invention according to a second aspect, the valve timing correction amount is a basic correction amount set based on the valve timing of the intake valve and the exhaust valve, and an operation set based on an engine operating state. It is characterized by being calculated by multiplying by a state correction coefficient. According to the second aspect of the present invention, the influence of the valve timing (the internal EGR amount or the like) also changes depending on the engine operating state.
More appropriate valve timing correction can be performed.

According to a third aspect of the present invention, the operating state correction coefficient is set such that the higher the rotational speed of the engine is,
The ignition timing is set so as to be more largely corrected to the advanced side as the load is larger. According to the third aspect of the present invention, even with the same valve timing, the internal EG increases as the engine speed increases and the load increases.
Since the R amount increases, it is possible to perform optimal correction weighting in accordance with the tendency.

According to a fourth aspect of the present invention, the valve timing correction amount is such that the valve overlap amount of the intake / exhaust valve is increased or decreased with respect to the reference position of the valve timing of the intake valve and the exhaust valve. The more the direction changes,
The ignition timing is set so as to be largely corrected to the advanced side.

According to the fourth aspect of the invention, when the amount of valve overlap with respect to the reference position of the valve timing increases, the amount of internal EGR increases and the ignitability delay increases, so that the amount of valve overlap increases. By correcting the advance of the ignition timing as it changes in the direction, the ignition can be performed at an appropriate timing.

On the other hand, when the valve overlap amount decreases by a predetermined amount or more, the effect of lowering the ignitability due to a decrease in the compression temperature due to the decrease in the internal EGR amount increases. The more the ignition timing is advanced, the more the ignition timing can be corrected to advance the ignition timing. The invention according to claim 5 is
The valve timing correction amount is set such that the more the valve timing of the intake valve and the exhaust valve changes in the advance direction or both in the retard direction with respect to the reference position, the more the ignition timing is corrected to the advance side. It is characterized by the following.

According to the fifth aspect of the present invention, even if the valve overlap center position deviates in either the advance side or the retard side with respect to a predetermined position (reference position) having a valve timing, the internal EGR is performed. Since the amount increases, ignition can be performed at an appropriate time by advancing the ignition timing.

According to a sixth aspect of the present invention, the finally set engine ignition timing is set by correcting a basic ignition timing set based on an engine operating state by the valve timing correction amount. It is characterized by the following.
According to the sixth aspect of the invention, the basic ignition timing set based on the engine operating state is corrected and set by the valve timing correction amount, so that the ignition timing is controlled to be optimally suitable for the combustibility. be able to.

The invention according to claim 7 is characterized in that the engine state parameters used for setting the basic ignition timing are a rotational speed and a load. The basic ignition timing can be optimally set using the most typical engine speed and load as parameters.

[0018]

Embodiments of the present invention will be described below. 1 to 6 show a variable valve timing mechanism provided in an engine in the present embodiment. In the figure, a cam sprocket 1 (timing sprocket) driven to rotate by a crankshaft (not shown) of an engine (internal combustion engine) via a timing chain, and a camshaft provided rotatably relative to the cam sprocket 1 2, a rotating member 3 fixed to an end of the camshaft 2 and rotatably accommodated in the cam sprocket 1, and a hydraulic circuit 4 for rotating the rotating member 3 relative to the cam sprocket 1. And a lock mechanism 10 for selectively locking a relative rotation position between the cam sprocket 1 and the rotating member 3 at a predetermined position.

The cam sprocket 1 has a rotating part 5 having teeth 5a on its outer periphery with which a timing chain (or a timing belt) meshes, and a rotating member 3 disposed in front of the rotating part 5 and rotatably accommodated therein. A housing 6, a disk-shaped front cover 7 serving as a lid for closing a front end opening of the housing 6, and a substantially disk disposed between the housing 6 and the rotating part 5 to close a rear end of the housing 6. The rotating part 5, the housing 6, the front cover 7, and the rear cover 8 are integrally connected by four small-diameter bolts 9 in the axial direction.

The rotating part 5 has a substantially annular shape, and each small-diameter bolt 9 is screwed at an equidistant position of about 90 ° in the circumferential direction.
One of the female screw holes 5b is formed to penetrate in the front-rear direction.
A fitting hole 11 having a stepped diameter is formed to penetrate. Further, a disc-shaped fitting groove 12 into which the rear cover 8 is fitted is formed in the front end face.

The housing 6 has a cylindrical shape with open front and rear ends, and four partition walls 13 are protruded from the inner peripheral surface at 90 ° in the circumferential direction. The partition 13 has a trapezoidal cross-section, and each has a housing 6.
Are provided along the axial direction of the
And four bolt insertion holes 14 through which the small-diameter bolt 9 is inserted are formed in the base end side in the axial direction. Further, a U-shaped sealing member 15 and a leaf spring 16 for pressing the sealing member 15 inward are fitted into a holding groove 13a which is cut out along the axial direction at the center position of the inner end surface of each partition 13. Is held.

Further, the front cover 7 has a relatively large-diameter bolt insertion hole 17 at the center thereof.
Four bolt holes 18 are formed in the housing 6 at positions corresponding to the bolt insertion holes 14. The rear cover 8 has a disk portion 8a fitted and held in the fitting groove 12 of the rotating member 5 on the rear end surface, and a small-diameter annular portion 25a of the sleeve 25 fits into the center. Fitting hole 8c
Are formed, and four bolt holes 19 are also formed at positions corresponding to the bolt insertion holes 14.

The camshaft 2 comprises a cylinder head 2
2 is rotatably supported via a cam bearing 23 at an upper end thereof, and a cam (not shown) for opening an intake valve via a valve lifter is integrally provided at a predetermined position on the outer peripheral surface. The part is provided integrally with a flange part 24. The rotating member 3 is fixed to the front end of the camshaft 2 by a fixing bolt 26 inserted from the axial direction through the sleeve 25 whose front and rear portions are fitted into the flange portion 24 and the fitting hole 11, respectively. An annular base 27 having a bolt insertion hole 27a through which the fixing bolt 26 is inserted, and four vanes 28a, 28b, 28 integrally provided at a position 90 ° in the circumferential direction of the outer peripheral surface of the base 27.
c, 28d.

The first to fourth vanes 28a to 28d are:
Each cross section has a substantially inverted trapezoidal shape, and is disposed in a concave portion between the partition portions 13, and separates the concave portion before and after in the rotational direction. In addition, an advance hydraulic chamber 32 and a retard hydraulic chamber 33 are configured. Further, the inner peripheral surface 6 of the housing 6 is inserted into a holding groove 29 which is notched in the axial direction at the center of the outer peripheral surface of each of the vanes 28a to 28d.
and a U-shaped seal member 30 slidably contacting the
The leaf springs 31 that press 0 outward are respectively fitted and held.

The lock mechanism 10 includes an engagement groove 20 formed at a predetermined position on the outer peripheral side of the fitting groove 12 of the rotating portion 5,
An engagement hole 21 formed through a predetermined position of the rear cover 8 corresponding to the engagement groove 20 and having a tapered inner peripheral surface;
A sliding hole 35 penetratingly formed along the inner axial direction at a substantially central position of the one vane 28 corresponding to the engagement hole 21.
A lock pin 34 slidably provided in the slide hole 35 of the one vane 28; and a coil spring 3 which is a spring member elastically mounted on the rear end side of the lock pin 34.
9 and a pressure receiving chamber 40 formed between the lock pin 34 and the sliding hole 35.

The lock pin 34 is formed with a middle-diameter main body 34a on the center side, an engaging portion 34b formed in a tapered conical shape on the front end side of the main body 34a, and a rear end side of the main body 34a. And a stopper portion 34c having a large-diameter stepped portion, and is engaged by the spring force of the coil spring 39 elastically mounted between the bottom surface of the internal concave groove 34d of the stopper portion 34c and the inner end surface of the front cover 7. In the pressure receiving chamber 40 formed between the main body 34a and the stopper 34c and between the main body 34a and the stopper 34c and between the main body 34a and the inner peripheral surface of the sliding hole 35. It slides in the direction of coming out of the engagement hole 21 by the hydraulic pressure.
The pressure receiving chamber 40 communicates with the retard side hydraulic chamber 33 through a through hole 36 formed in a side portion of the vane 28. The engaging portion 34b of the lock pin 34 engages with the engaging hole 21 at the rotation position on the maximum retard side of the rotating member 3.

The hydraulic circuit 4 comprises a first hydraulic passage 41 for supplying and discharging hydraulic pressure to and from the advance hydraulic chamber 32, and a second hydraulic passage 42 for supplying and discharging hydraulic pressure to the retard hydraulic chamber 33. The two hydraulic passages 41 and 42 have
The supply passage 43 and the drain passage 44 are connected to each other via an electromagnetic switching valve 45 for switching the passage. An oil pump 47 for pumping oil in an oil pan 46 is provided in the supply passage 43, while a downstream end of the drain passage 44 communicates with the oil pan 46.

The first hydraulic passage 41 has a first hydraulic passage 41 formed inside the cylinder head 22 and inside the axis of the camshaft 2.
A passage portion 41a, a first oil passage 41b branched and formed in the head portion 26a through the axial direction inside the fixing bolt 26 and communicating with the first passage portion 41a, a small-diameter outer peripheral surface of the head portion 26a, and a rotating member An oil chamber 41c formed between the inner peripheral surface of the bolt insertion hole 27a provided in the base 27 of the third rotating member 3 and communicating with the first oil passage 41b; It is composed of a chamber 41c and four branch passages 41d communicating with each advance-side hydraulic chamber 32.

On the other hand, the second hydraulic passage 42 is formed in the cylinder head 22 and on one side inside the camshaft 2 and a substantially L-shaped bent portion inside the sleeve 25. A second oil passage 42b communicating with the second passage portion 42a, and four oil passage grooves 42 formed at the outer peripheral side edge of the fitting hole 11 of the rotating member 5 and communicating with the second oil passage 42b.
c and four oil holes 42d formed at about 90 ° in the circumferential direction of the rear cover 8 and communicating each oil passage groove 42c and the retard side hydraulic chamber 33.

The electromagnetic switching valve 45 controls the relative switching between the hydraulic passages 41 and 42, the supply passage 43, and the drain passages 44a and 44b by an internal spool valve body. The switching operation is performed by the control signal of (1). Specifically, as shown in FIGS. 4 to 6, a cylindrical valve body 51 inserted and fixed in the holding hole 50 of the cylinder block 49.
A spool valve body 53 slidably provided in a valve hole 52 in the valve body 51 for switching a flow path, and a proportional solenoid type electromagnetic actuator 54 for operating the spool valve body 53. .

In the valve body 51, a supply port 55 for communicating the downstream end of the supply passage 43 with the valve hole 52 is formed at a substantially central position of the peripheral wall, and the supply port 55 is provided on both sides of the supply port 55. First and second hydraulic passages 41 and 42
A first port 56 and a second port 57 that communicate the other end of the valve and the valve hole 52 are formed through each. The two drain passages 44a, 44b and the valve hole 5 are provided at both ends of the peripheral wall.
Third and fourth ports 58 and 59 communicating with the second port 2 are formed through.

The spool valve body 53 has a substantially cylindrical first valve portion 60 for opening and closing the supply port 55 at the center of the small diameter shaft portion, and has third and fourth ports 58 and 5 at both ends.
9 has a substantially cylindrical second and third valve portions 61 and 62 for opening and closing the valve 9. Further, the spool valve element 53 is connected to the front end shaft 5.
A conical valve spring 63 elastically mounted between an umbrella portion 53b provided on one end edge of the valve 3a and a spring seat 51a provided on an inner peripheral wall on the front end side of the valve hole 52, to the right in the drawing, that is, the first valve portion 60. Urged in a direction to connect the supply port 55 with the second hydraulic passage 42.

The electromagnetic actuator 54 includes a core 6
4, a moving rod 65a that includes a moving plunger 65, a coil 66, a connector 67, and the like, and that presses an umbrella portion 53b of the spool valve body 53 is fixed to an end of the moving plunger 65. The controller 48 detects a current operating state (load, rotation) based on signals from a rotation sensor 101 for detecting an engine rotation speed and an air flow meter 102 for detecting an intake air amount, and a crank angle sensor 1.
03 and a signal from the cam sensor 104, the relative rotation position between the cam sprocket 1 and the cam shaft 2, that is,
The rotational phase of the camshaft 2 with respect to the crankshaft is detected.

The controller 48 controls the amount of current supplied to the electromagnetic actuator 54 based on a duty control signal. For example, a control signal (OF) having a duty ratio of 0% is sent from the controller 48 to the electromagnetic actuator 54.
When the F signal is output, the spool valve body 53
The position shown in FIG. 4, that is, the maximum rightward direction is moved by the spring force. Accordingly, the first valve portion 60 opens the open end 55a of the supply port 55 to communicate with the second port 57, and at the same time, the second valve portion 61 opens the open end of the third port 58, and the fourth The valve part 62 closes the fourth port 59. Therefore, the hydraulic oil pumped from the oil pump 47 is supplied to the supply port 55, the valve hole 52, the second port 57,
The hydraulic oil is supplied to the retard hydraulic chamber 33 through the hydraulic passage 42 and the hydraulic oil in the advance hydraulic chamber 32 is supplied to the first hydraulic passage 4.
The oil is discharged from the first drain passage 44a into the oil pan 46 through the first port 56, the valve hole 52, and the third port 58.

Accordingly, the internal pressure of the retard side hydraulic chamber 33 becomes high, and the internal pressure of the advance side hydraulic chamber 32 becomes low, so that the rotating member 3 rotates in at most one direction via the vanes 28a to 28b. As a result, the cam sprocket 1 and the camshaft 2 rotate relatively to one side to change the phase. As a result, the opening timing of the intake valve is delayed, and the overlap with the exhaust valve is reduced.

On the other hand, when a control signal (ON signal) having a duty ratio of 100% is output from the engine control unit (ECU) 48 for performing various engine controls to the electromagnetic actuator 54, the spool valve body 53 resists the spring force of the valve spring 63. Then, as shown in FIG. 6, the third valve portion 61 closes the third port 58 and the fourth valve portion 62 opens the fourth port 59 at the same time as the third valve portion 61 closes to the left.
The first valve section 60 makes the supply port 55 communicate with the first port 56. Therefore, the hydraulic oil is supplied to the advance hydraulic chamber 32 through the supply port 55, the first port 56, and the first hydraulic passage 41, and the hydraulic oil in the retard hydraulic chamber 33 is supplied to the second hydraulic chamber 32. Hydraulic passage 42, second port 57, fourth port 5
9. The oil is discharged to the oil pan 46 through the second drain passage 44b, and the pressure in the retard hydraulic chamber 33 becomes low.

For this reason, the rotating member 3 includes the vanes 28a to 28a.
Rotate in the other direction to the maximum through 28d,
The cam sprocket 1 and the camshaft 2 relatively rotate to the other side to change the phase. As a result, the opening timing of the intake valve is advanced (advanced), and the overlap with the exhaust valve is increased. The ECU 48 determines a position where the first valve portion 60 closes the supply port 55, the third valve portion 61 closes the third port 58, and the fourth valve portion 62 closes the fourth port 59. Base duty ratio BAS
On the other hand, the relative rotation position (rotation phase) between the cam sprocket 1 and the camshaft 2 detected based on the signals from the crank angle sensor 103 and the cam sensor 104, and the relative rotation set according to the operating state. A feedback correction amount UDTY for matching the target value (target advance value) of the moving position (rotational phase) is set, and the result of adding the base duty ratio BASEDTY and the feedback correction amount UDTY is set to a final duty ratio VTCD.
TY, and a control signal of the duty ratio VTCDTY is output to the electromagnetic actuator 54.

The base duty ratio BASED
In the TY, the supply port 55, the third port 58, and the fourth port 59 are all closed, and the oil pressure is not supplied to or discharged from any of the hydraulic chambers 32, 33. Is set. That is, when it is necessary to change the relative rotation position (rotational phase) in the retard direction, the duty ratio is reduced by the feedback correction amount UDTY, and the hydraulic oil pumped from the oil pump 47 is shifted to the retard side. While being supplied to the hydraulic chamber 33, the hydraulic oil in the advance hydraulic chamber 32 is discharged into the oil pan 46, and conversely, the relative rotation position (rotation phase) changes in the advance direction. If necessary, the duty ratio is increased by the feedback correction amount UDTY, the hydraulic oil is supplied into the advance hydraulic chamber 32, and the hydraulic oil in the retard hydraulic chamber 33 is supplied to the oil pan 46. Will be discharged. When the relative rotational position (rotational phase) is maintained in the current state, the absolute value of the feedback correction UDTY is reduced, so that the duty ratio is controlled to return to a duty ratio near the base duty ratio. 5
5. By closing the third port 58 and the fourth port 59 (stopping the supply and discharge of the hydraulic pressure), the internal pressure of each of the hydraulic chambers 32 and 33 is controlled.

Here, the feedback correction UDT
Y is set, for example, by normal PID control. That is, when the detected relative rotation position (rotation phase) between the cam sprocket 1 and the camshaft 2 is the actual angle VTCNOW of the variable valve timing mechanism (VTC) and the target value is the target angle VTCTRG of VTC,
The difference VTCERR (= VTCNOW−VTCTR)
G) is controlled by setting a proportional component P, an integral component I, and a differential component D.

FIG. 7 shows a system configuration of an engine provided with the variable valve timing mechanism. In the figure, the variable valve timing mechanisms (VTC) 121 and 122 are provided on the intake valve side and the exhaust valve side. Engine 20
In one intake passage 202, a fuel injection valve 203 for injecting fuel for each cylinder is provided. The fuel and air injected from the fuel injection valve 203 are premixed, and the fuel is injected into the cylinder via an intake valve 204. Is sucked. The combustion mixture in the cylinder is ignited and burned by spark ignition by the spark plug 205,
The combustion exhaust is discharged to an exhaust passage 207 via an exhaust valve 206.

In the exhaust passage 207, a three-way catalyst 208 is interposed.
C and NOx are purified. On the upstream side of the three-way catalyst 208, an air-fuel ratio sensor 20 for detecting an air-fuel ratio by having a characteristic that an output value changes with a change in an exhaust air-fuel ratio.
9 are interposed.

A throttle valve 210 for controlling the amount of intake air is interposed in the intake passage 202, and a throttle sensor 2 for detecting the opening of the throttle valve 120.
An air flow meter 102 for detecting the amount of intake air is provided further upstream. Others
A water temperature sensor 212 for detecting the engine cooling water temperature Tw is provided.

The detection signal of each sensor is transmitted to the ECU 4
The ECU 48 performs the valve timing control of the intake valve 204 by the VTC 121, the fuel injection amount control by the fuel injection valve 203, the ignition control by the spark plug 205, and the like. Hereinafter, the ignition control according to the present invention will be described with reference to the flowcharts of FIG.

In FIG. 8 showing the main routine of the ignition control, in step 1, the engine speed Ne detected by the crank angle sensor 101, the basic fuel injection amount Tp as the engine load calculated in another routine,
Intake valve 204 detected by cam sensor 104
And the actual valve timing VTCN of the exhaust valve 206
OW (int), VTCNOW (exh), etc. are read.

In step 2, the engine speed N
e, basic ignition timing ADV based on basic fuel injection amount Tp, etc.
b is set by a search from a preset map or the like. In step 3, a VTC correction amount ADVvtc according to VTC control of the ignition timing is calculated.

In step 4, the final engine ignition timing ADV is set by the following equation. ADV = A
DVb + ADVvtc In step 5, the ignition timing A
An ignition signal is output to the ignition plug 205 by DV, and ignition is performed by a spark.

FIG. 9 shows the correction amount A in step 3 described above.
5 shows a flowchart of a subroutine for calculating DVvtc. In step 11, the intake valve 204 and the exhaust valve 2
06 actual valve timing VTCNOW (int), V
Based on TCNOW (exh), VTC basic correction amount A
DVvtcb is searched in advance from a map as shown in FIG.

Here, the characteristics of the VTC basic correction amount ADVvtcb set on the map will be described. Now, assuming that the valve timing of the intake valve 204 and the exhaust valve 206 when the VTC basic correction amount ADVvtcb is set to the most retarded side is a reference position, first, the valve overlap of the intake and exhaust valves with respect to the reference position. The ignition timing is set to be more largely corrected to the advanced side as the amount increases (direction a in the figure), that is, as the intake valve 204 advances and the exhaust valve 206 changes toward the retard side. That is, when the valve overlap amount increases, the internal EGR
The ignition timing is corrected to advance the ignition timing because the ignition amount is increased due to the increase in the ignition timing.

As the valve timings of the intake valve 204 and the exhaust valve 206 change in the advance direction (direction b in the drawing) or in the retard direction (direction c in the drawing) with respect to the reference position, the ignition timing advances. It is set so as to largely correct the corner side. In these directions, the valve overlap amount does not change, but the internal EGR amount increases regardless of whether the valve overlap center position is shifted to the advance side or the retard side with respect to the reference position. Is corrected.

A direction in which the valve overlap amount of the intake / exhaust valve with respect to the reference position decreases (direction d in the figure);
That is, the ignition timing is set to be more largely corrected to the advanced side as the intake valve 204 is retarded and the exhaust valve 206 is advanced in the direction of advanced angle. In this case, although the valve overlap amount decreases, the effect of the ignition delay caused by the decrease in the compression temperature due to the decrease in the internal EGR amount becomes greater, so that the ignition timing is set to be largely corrected to the advanced side. Is done.

In step 12, the engine speed N
e, The operating state correction coefficient Kvtc is set in advance from the map shown in FIG. 11 based on the basic fuel injection amount Tp (load). Here, the operating state correction coefficient Kvtc is set to a value greater than 1 as the engine speed Ne and the load increase. That is, as the engine rotational speed Ne and the load are higher, the internal EGR amount is larger and the ratio of the change amount of the internal EGR amount to the change amount of the valve overlap amount is increased even with the same valve overlap amount. The ignition timing is set so as to be more largely corrected on the advance side.

In step 13, based on the VTC basic correction amount ADVvtcb set in step 11 and the operating state correction coefficient Kvtc set in step 12, the final VTC correction amount ADVvtc is set by the following equation.
ADVvtc = ADVvtcb × Kvtc In this case, the engine ignition timing is adjusted based on the actual valve timings of the intake valves and the exhaust valves using the minimum necessary map data and the valve timing correction amount corresponding to the combustibility. Optimum control can be performed.

As a variable valve timing mechanism,
In addition to the hydraulic control system, the present invention can be applied to a system in which the rotation phase of a camshaft is variably controlled by an electromagnetic brake, and a system in which intake and exhaust valves are directly electromagnetically driven.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a variable valve timing mechanism according to an embodiment.

FIG. 2 is a sectional view taken along line BB of FIG. 1;

FIG. 3 is an exploded perspective view of the variable valve timing mechanism.

FIG. 4 is a longitudinal sectional view showing an electromagnetic switching valve in the variable valve timing mechanism.

FIG. 5 is a longitudinal sectional view showing an electromagnetic switching valve in the variable valve timing mechanism.

FIG. 6 is a longitudinal sectional view showing an electromagnetic switching valve in the variable valve timing mechanism.

FIG. 7 is a diagram showing a system configuration of an engine including the variable valve timing mechanism.

FIG. 8 is a flowchart showing a main routine of the engine ignition control.

FIG. 9 is a flowchart showing a subroutine for calculating a VTC correction amount ADVvtc for the ignition timing.

FIG. 10 shows the VTC basic correction amount ADVvt for the ignition timing.
Map with cb set.

FIG. 11 is a map in which the operating state correction coefficient Kvtc for the ignition timing is set.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 ... Rotation sensor 102 ... Air flow meter 103 ... Crank angle sensor 104 ... Cam sensor 121,122 ... Variable valve timing mechanism 201 ... Engine 204 ... Intake valve 205 ... Spark plug 206 ... Exhaust valve

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F02D 43/00 301 F02P 5/15 BCF term (reference) 3G018 AB17 BA32 BA33 CA20 DA58 DA66 DA72 DA73 EA00 EA02 EA16 EA22 EA31 EA32 FA01 FA07 FA09 GA08 3G022 CA08 CA09 DA01 GA00 GA05 GA06 GA08 GA09 3G084 BA17 BA23 DA06 EB11 FA07 FA10 FA18 FA20 FA33 3G092 AA01 AA11 BA09 DA01 DA02 DA09 DF09 DG05 DG09 EA01 EC03 EA01 EC03 HA03 HE01Z HE08Z

Claims (7)

[Claims] 1. The valve timing of an intake valve and an exhaust valve is:
In an engine ignition control device that is independently and continuously variably controlled, a valve timing of an intake valve and an exhaust valve is detected, and a valve timing correction amount of an engine ignition timing is set based on the detected values. An ignition control device for an engine, wherein ignition control is performed at an ignition timing corrected by the valve timing correction amount. 2. The valve timing correction amount is calculated by multiplying a basic correction amount set based on valve timings of the intake valve and the exhaust valve by an operating state correction coefficient set based on an engine operating state. The ignition control device for an engine according to claim 1, wherein: 3. The operating state correction coefficient is set such that the ignition timing is corrected to be more advanced toward the advance side as the rotation speed of the engine is higher and the load is higher. An ignition timing control device for an engine according to Claim 1. 4. The valve timing correction amount is set such that as the valve timing of the intake valve and the exhaust valve changes in the direction in which the valve overlap amount of the intake and exhaust valves increases or decreases with respect to the reference position, the ignition timing increases. The ignition timing control device for an engine according to any one of claims 1 to 3, wherein the ignition timing control device is set so as to largely correct the ignition timing on the advance side. 5. The valve timing correction amount according to claim 1, wherein the more the valve timing of the intake valve and the exhaust valve changes in the advance direction or both in the retard direction with respect to the reference position, the greater the ignition timing is advanced to the advance side. The ignition timing control device for an engine according to any one of claims 1 to 4, wherein the ignition timing control device is set as follows. 6. The engine ignition timing finally set is:
The ignition timing of an engine according to any one of claims 1 to 5, wherein a basic ignition timing set based on an engine operation state is corrected and set by the valve timing correction amount. Control device. 7. The engine ignition control device according to claim 6, wherein the parameters of the engine state used for setting the basic ignition timing are a rotational speed and a load.