JPH09195840A - Fuel injection control device of internal combustion engine furnishing variable moving valve mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reduction of exhaust performance at the restarting condition, by providing a fuel injection permitting means to permit the fuel injection, when the timing of the suction and the exhaust valves reaches to the valve timing at the starting condition. SOLUTION: In an internal combustion engine furnishing a variable moving valve mechanism, a suction cam 4 is provided to a suction cam shaft 2 at each cylinder, and a variable timing device 5 is provided at its front end. In this variable timing device 5, the structure is made to control variable the suction cam 4, by delaying the phase of the intake cam shaft 2 to a cam sprocket 3 by controlling a hydraulic control valve 8 by a C/U 14. In this case, a valve timing deciding part 16 to decide whether the valve timing at the engine restarting condition is returned to a specific starting time valve timing or not; and a fuel injection permitting part 17 to permit the injection of the starting fuel when it is returned to the starting valve timing; are provided in the C/U 14, so as to prevent the blowby of the injection fuel to the exhaust side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device for an internal combustion engine equipped with a variable valve mechanism capable of variably setting valve timings of intake and exhaust valves, and more particularly to a valve timing at start when the engine is stopped. The present invention relates to a fuel injection control device for an internal combustion engine equipped with a variable valve mechanism having the characteristics described below.

[0002]

2. Description of the Related Art For example, in a low-rotation, low-load running region such as during idling, it is desirable that there be little valve overlap in which intake and exhaust valve opening timings overlap. On the other hand, it is preferable that the valve overlap is large in the high rotation and high load traveling range. Therefore, in order to meet these contradictory requirements, in recent years, various internal combustion engines having a variable valve mechanism capable of variably adjusting the valve timings of intake and exhaust valves according to operating conditions have been proposed.

As the variable valve mechanism, a cam twist type (or variable center angle type) in which a camshaft is rotated to variably control an operation center angle, and a camshaft arranged on the outer periphery of the drive shaft with respect to the drive shaft is used. There are known a variable operating angle type in which the operating angle is variably controlled by rotating at a non-uniform speed, and a cam switching type in which the cam timing is variably controlled by switching the cams having different operating angles. Both are usually
When the engine is stopped, in preparation for restarting, the valve timing is automatically returned to the valve timing at the time of starting as an initial state.

[0004]

By the way, according to the above-mentioned prior art, when the engine is stopped due to an engine stall or the like at the time of partial load (partial time) when the valve overlap is set to a large value, the cam counteracts due to the valve lift. The valve overlap just before the engine is stopped may be maintained as it is due to the force, frictional force of the cam drive transmission system (for example, drive belt, drive chain), and ring gear.

Therefore, the engine may be restarted with a large valve overlap set according to the partial load traveling range, and the starting fuel injected at the time of restart is excessive on the exhaust side. There is a risk that the air will blow through and the exhaust performance will deteriorate.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to control fuel injection of an internal combustion engine having a variable valve mechanism capable of preventing deterioration of exhaust performance at restart. To provide a device.

[0007]

SUMMARY OF THE INVENTION Therefore, according to the present invention, when the engine is restarted, only when it is detected that the valve timing at the time of starting is reached or when it can be considered that the valve timing at the time of starting is reached, By allowing the fuel injection, it is possible to prevent the injected fuel from excessively passing through to the exhaust side.

That is, the structure adopted by the fuel injection control apparatus for an internal combustion engine equipped with the variable valve mechanism according to the present invention is the fuel for the internal combustion engine equipped with the variable valve mechanism for variably controlling the opening / closing timing of the intake and exhaust valves. The injection control device is characterized in that a fuel injection permission means for permitting fuel injection is provided when the valve timing of the intake and exhaust valves reaches the valve timing at the time of starting. Thus, when the engine is restarted, the injection of the starting fuel is not permitted unless the valve timing of the intake / exhaust valve is returned to the valve timing at the start.

According to a second aspect of the invention, there is provided a fuel injection control device for an internal combustion engine, comprising a variable valve mechanism for variably controlling the opening / closing timing of the intake / exhaust valve, wherein Valve timing detection means for detecting valve timing, valve timing determination means for determining whether or not the detected valve timing has reached the startup valve timing, and the valve timing of the intake and exhaust valves is set as the startup valve timing. And a fuel injection permission means for permitting fuel injection when the time is reached. As a result, the injection of the starting fuel is blocked until the valve timing of the intake / exhaust valve detected by the valve timing detecting means reaches the valve timing at the time of starting.

According to a third aspect of the present invention, there is provided a fuel injection control device for an internal combustion engine, comprising a variable valve mechanism for variably controlling the opening / closing timing of intake / exhaust valves, wherein a predetermined delay time has elapsed at engine startup. It is characterized in that fuel injection permission means for permitting fuel injection is provided in the. By setting the delay time according to the characteristics of the variable valve mechanism, it is possible to inject the starting fuel when the valve timing returns to the starting valve timing without directly detecting the valve timing. it can.

The invention according to claim 4 is characterized in that the delay time is set based on a parameter related to the valve timing of the intake and exhaust valves. The time required for the valve timing of the intake / exhaust valve to return to the valve timing at startup at the time of engine restart varies variously depending on the characteristics of the variable valve mechanism, operating conditions, and the like. Therefore, a parameter related to valve timing, that is, a parameter that influences the return time to the valve timing at the time of starting is selected in advance by an actual machine test or simulation, and the delay time is set according to the value of this parameter. As a result, fuel injection can be started exactly at the time when the valve timing at startup is reached.

Specifically, the invention according to claim 5 is characterized in that, as the parameter, either the temperature of the working fluid for driving the variable valve mechanism or the engine cooling water temperature is used. The viscosity of the working fluid (working oil) changes depending on the temperature, and this viscosity changes the time required to return to the valve timing at startup. Therefore, the optimum delay time can be set by indirectly detecting the viscosity of the working fluid via the temperature of the working fluid or the temperature of the engine cooling water.

The invention according to claim 6 is characterized in that cranking rotation is used as the parameter. When cranking is started by restarting, the return force of the return spring, etc. gradually returns to the valve timing at the time of starting, so after starting the cranking rotation, a predetermined delay time elapses before starting. By injecting the fuel, the fuel can be supplied at a time when the valve timing is almost returned to the starting timing.

The invention according to claim 7 is characterized in that a cam state of the variable valve mechanism when the engine is stopped is used as the parameter. The time required to return to the valve timing at startup varies depending on the cam state when the engine is stopped, such as the operating angle and the operating center angle. Therefore, by setting the delay time based on the cam state, it is possible to inject the starting fuel at the timing when the valve timing at the time of starting is returned.

In the invention according to claim 8, a V-type internal combustion engine having a variable valve operating mechanism in each of the left and right banks is used as the internal combustion engine provided with the variable valve operating mechanism, and the starting is performed first in the left and right banks. The feature is that fuel injection is permitted from the bank side when the hour valve timing is reached. As a result, if one of the left and right banks returns to the starting valve timing earlier than the other,
Fuel injection on the bank side is started first. Therefore, due to the increase in the engine speed due to the fuel injection of this one bank, the other bank returns to the valve timing at the time of startup in a shorter time than during the normal cranking.

[0016]

According to the fuel injection control device for an internal combustion engine equipped with the variable valve mechanism according to the present invention, when the engine is restarted,
The starting fuel is not injected unless the valve timing of the intake / exhaust valve returns to the valve timing at startup. Therefore,
It is possible to prevent the starting fuel from being injected in the state where the valve overlap is large, and to prevent the injected fuel from excessively blowing to the exhaust side and deteriorating the exhaust.

Further, according to the configuration in which the starting fuel is injected after the lapse of a predetermined delay time, the starting fuel is not detected directly when the valve timing returns to the starting valve timing, and the starting fuel is injected. Injection can be performed and the control structure can be simplified.

More specifically, the delay time is set based on a parameter related to the valve timing of the intake / exhaust valve, so that fuel injection can be started more accurately at the timing when the valve timing at startup is reached. It is possible to prevent deterioration of exhaust gas.

If the temperature of the working fluid or the temperature of the engine cooling water is used as a specific parameter, the optimum delay time can be set according to the viscosity of the working fluid that affects the return time to the valve timing at the start. It is possible to prevent deterioration of exhaust gas.

Also, by using the cranking rotation as a parameter, the starting fuel can be supplied almost at the time of returning to the valve timing at the time of starting, and exhaust deterioration can be prevented.

Further, even when the cam state when the engine of the variable valve mechanism is stopped is used as the parameter, it corresponds to the return time to the valve timing at the time of starting, which changes depending on the cam state such as the operating angle and the operating central angle. At the timing, the starting fuel can be injected, and exhaust deterioration can be prevented.

As an internal combustion engine having a variable valve mechanism, a V-type internal combustion engine having a variable valve mechanism in each of the left and right banks is used. With the configuration that allows injection, it is possible to start the fuel injection on the side that returns to the valve timing at startup earlier in either of the left and right banks, and the engine rotation by the fuel injection of this preceding one bank Due to the increase in the number, the recovery time of the other bank can be shortened compared to the recovery time by normal cranking,
It is possible to improve the drivability by shortening the restart time while preventing the deterioration of exhaust gas.

[0023]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG.

First, FIG. 1 is a structural explanatory view showing the overall structure of a fuel injection control device for an internal combustion engine equipped with a variable valve mechanism according to a first embodiment of the present invention. ,
An intake camshaft 2 for driving an intake valve (not shown) is provided above the cylinder head. Although not shown, an exhaust cam shaft for driving the exhaust valve is also arranged above the cylinder head along the longitudinal direction of the engine body 1 to form a DOHC engine. Hereinafter, the intake camshaft 2 side will be described.

A front portion of the intake camshaft 2 is connected to a crankshaft (neither is shown) via a cam sprocket 3 and a drive chain, and a rear portion of the intake camshaft 2 is pivotally supported by the engine body 1. There is. The intake camshaft 2 is provided with a set of two intake cams 4 axially separated from each other for each cylinder, and a variable valve timing device 5 is provided at the front end of the intake camshaft 2. ,
This constitutes a "variable valve mechanism".

The variable valve timing device 5 delays the phase of the intake camshaft 2 with respect to the cam sprocket 3 by supplying / discharging the control hydraulic pressure to variably control the operation central angle of the intake cam 4. And
The pair of intake cams 4 swing the intake rocker arm 7 supported by the rocker shaft 6 to open and close the intake valve. Here, the variable valve timing device 5 is, as will be described later with reference to FIG. 8, an inner housing axially connected to the front end of the intake camshaft 2 through a mounting bolt or the like, and is separated from the outer peripheral side of the inner housing. The outer housing provided, the first and second helical gears axially movable in the annular chamber between the housings, and the helical gears in the direction that always forms the valve timing at the time of starting. The engine main body 1 is roughly composed of a return spring that biases the return spring and a hydraulic passage (none of which is shown) that supplies hydraulic pressure to move the helical gears against the return force of the return spring. When stopped, each helical gear is pushed back to the initial position by the spring force of the return spring, which causes the valve valve to start at the start. So as to form the timing.

In the figure, 9 is a crank angle sensor for detecting the engine speed N, 10 is a water temperature sensor for detecting the engine cooling water temperature T _w , 11 is an air flow meter for detecting the intake air amount Q, and 12 is a cam angle θ. A cam angle sensor for detecting _C , 13 indicates a starter switch for detecting the operation of a starter motor (not shown), and each of these sensors includes a throttle sensor (not shown), an air-fuel ratio sensor, etc., and a control unit described later. It is connected to 14. Here, the cam angle sensor 12 constitutes "valve timing detecting means".

The engine body 1 is provided with a hydraulic control valve 8 which is, for example, a normally open solenoid valve. The hydraulic control valve 8 is controlled to be opened / closed by the control unit 14, and controls the hydraulic pressure supplied to the variable valve timing device 5 to be turned on / off to change the phase of the intake camshaft 2.

The control unit 14 for electrically and centrally controlling the engine is constructed as a microcomputer system including, for example, a CPU, a RAM, a ROM and an input / output interface (none of which is shown). On the output side of the control unit 14, the hydraulic control valve 8,
Each fuel injection valve 15 and a spark plug (not shown) are connected, and the fuel injected from each fuel injection valve 15 at a predetermined fuel injection timing is forcibly ignited by the spark plug. here,
The control unit 14 calculates a fuel injection amount according to the operating state of the engine body 1 to control the operation of each fuel injection valve 15, and a control unit 14 according to the operating state of the engine body 1. A valve timing control unit (both not shown) that controls the variable valve timing device 5 to realize the optimum valve timing is provided.

As a characteristic internal function of the control unit 14, a valve as "valve timing determining means" for determining whether or not the valve timing at engine restart has returned to a predetermined valve timing at startup. A timing determination unit 16 and a fuel injection permission unit 17 as “fuel injection permission means” that permits injection of the starting fuel when the valve timing at the time of startup is restored are provided.

Next, the operation of this embodiment will be described with reference to FIGS. First, FIG. 2 is a flowchart showing a control process at the time of starting the engine. In step (indicated as “S” in the figure) 1, the engine key is inserted and rotated to “ACC” → “ignition” → “start”.
When the signals are generated in this order, power supply to the starter motor is started, and cranking by the starter motor is started. Next, in step 2, the current valve timing is detected by the cam angle θ _C detected by the cam angle sensor 12, and in step 3, whether or not the detected valve timing is the valve timing at the time of starting, that is, it is variable. By the return spring etc. of the valve timing device 8,
Monitor whether the valve timing has returned to the valve timing at startup.

Then, when the valve timing is returned to the valve timing at the time of starting, the step 3 is "YE
S ”is determined and the process proceeds to step 4. In this step 4, the fuel injection permission is given to the normal fuel injection control section, whereby the injection of the starting fuel is started.

According to the present embodiment configured as described above,
The following effects are obtained.

First, since the fuel injection permission section 17 is provided for permitting fuel injection when the valve timing of the intake / exhaust valves reaches the valve timing at the time of starting, for example, engine stall is performed during partial load traveling with a large valve overlap. Even when the engine body 1 is stopped due to such reasons, at the time of restarting, it is possible to inject and supply the starting fuel after waiting for the return to the valve timing at the time of starting. As a result, even if the restart is started while the valve overlap value is large due to the frictional force of the drive system of the intake cam 2 and the cam reaction force, the fuel is not injected unless the valve timing at the start is restored. It is possible to effectively prevent the starting fuel from excessively blowing to the exhaust side and deteriorating the exhaust gas.

This point will be described with reference to FIG. FIG. 3 is a timing chart showing changes over time in the fuel injection timing, the valve overlap amount, and the engine speed at the time of start-up, and during the time when the engine body 1 is in the partial load traveling range where the valve overlap is large, the time is shown. When the engine is stopped due to an engine stall or the like at T ₀ , the variable valve timing device 5 tries to return the valve timing to the valve timing at the time of starting by the built-in return spring. However, due to the cam reaction force and the frictional force of the chain, ring gear, etc., the phase of the camshaft 2 does not immediately return to the valve timing at the time of starting as the initial state, so the valve overlap still maintains a large value.

When the driver operates the engine key to restart the engine at time T ₁ , the starter motor is driven and cranking is started. Here, in the related art, since the return delay of the valve timing is not taken into consideration, fuel injection is started at time T ₃ after the start of cranking. However, due to the frictional force and the like, the valve overlap is still large. Therefore, as shown by the dotted line in FIG. 3, when fuel is injected at this time T ₀ , a larger amount of fuel than the normal value is discharged to the exhaust side. It will blow through and the exhaust performance will deteriorate.

On the other hand, in the present embodiment, since the fuel injection is permitted after waiting until the time T ₂ at which the valve timing at the time of start-up where the valve overlap is small due to the start of cranking is restored, the fuel above the normal value is exhausted. Exhaust performance can be improved without blowing through to the side.

Secondly, specifically, the valve timing is detected by the cam angle θ _C detected by the cam angle sensor 12, and the valve timing determination unit 16 determines that this valve timing has reached the valve timing at the time of starting. At this time, since the fuel injection permission unit 17 permits the start of fuel injection, it is possible to inject the starting fuel after confirming that the actual valve timing has returned to the valve timing at the time of starting, thus further improving the exhaust performance. Can be improved.

The "valve timing detecting means" is not limited to the cam angle sensor 12, but the hydraulic pressure controlled by the hydraulic control valve 8 is detected by the pressure sensor, and the valve timing is detected by the detected hydraulic pressure. It may be configured to. Since the variable valve timing device 5 is hydraulically controlled, the valve timing can be indirectly detected by monitoring the hydraulic pressure.

Next, a second embodiment of the present invention will be described with reference to FIGS. In each of the following embodiments, the same components as those in the first embodiment are designated by the same reference numerals,
The description is omitted. A feature of the present embodiment is that a delay time for returning to the valve timing at the time of starting with a small valve overlap at the time of restart is set in advance, and the fuel injection start is permitted after the delay time has elapsed.

FIG. 4 is a functional block diagram showing the internal functions of the control unit 21 according to the present embodiment. The control unit 21 judges that the valve timing at the time of startup is considered to have returned to the valve timing at the time of starting after the delay time elapses. 22 and valve timing determination unit 2
The fuel injection permission section 23 permits the fuel injection start by the fuel injection valve 15 when it is considered that 2 has reached the valve timing at the time of starting. Further, the valve timing determination unit 22 includes a delay time setting unit 25 connected to an oil temperature sensor 24 that detects a temperature t _A of hydraulic oil as a “working fluid” that is switched and controlled by the hydraulic control valve 8, and an oil _A temperature-delay time map 26 in which a delay time Td corresponding to the temperature t _A is mapped, and whether or not the delay time Td set on the basis of this map 26 has elapsed is determined based on timing information of a timer 27. And a delay time determination unit 28 for

Here, the oil temperature t _A of the hydraulic oil is an example of "a parameter relating to the valve timing of the intake and exhaust valves". This is because the viscosity of the hydraulic oil changes depending on the oil temperature t _A , which affects the operating time of the variable valve timing device 5 (the viscosity increases as the temperature decreases, and the recovery time increases as the viscosity increases). Become). Therefore, the viscosity of the hydraulic oil is determined by the engine cooling water temperature T _w by the water temperature sensor 10,
It may be configured to detect more indirectly. In this case, the hydraulic oil viscosity is detected more indirectly, but the structure can be simplified.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. First, this program is started when the engine key is rotated to the “start” position, and in step 11, the oil temperature t _A is detected by the oil temperature sensor 24. Next, in step 12, the temperature-delay time map 26 is based on the detected oil temperature t _A.
The delay time Td corresponding to the oil temperature t _A is read from and is set by the delay time setting unit 25. Next, in step 13,
Start cranking by rotating the starter motor.

Then, in step 14, the timer 27 is started to start time counting, and in step 15
Then, the delay time determination unit 28 monitors whether the delay time Td has elapsed. When the delay time Td elapses and the time is up, it is determined to be "YES" in step 15, and in step 16, the fuel injection permitting section 23 permits the fuel injection start of the fuel injection valve 15.

Also in this embodiment having the above-mentioned configuration, FIG.
As shown in the figure, in order to allow the fuel injection to start after waiting for a predetermined delay time Td from restarting the engine, the fuel should be supplied after the valve timing at the time of startup with a small valve overlap. It is possible to prevent deterioration of exhaust performance.

Especially, unlike the first embodiment, the valve timing is not always monitored, but only the elapse of the delay time Td set at the time of restart is waited, so that the control structure is simplified. You can

Second, the temperature t _A of the hydraulic oil of the hydraulic control valve 8
Since the delay time Td is set in accordance with the above, the fuel can be injected more accurately at the timing when the valve timing at the time of startup is reached.

In this embodiment, the oil temperature t _A of the hydraulic oil is used as a parameter related to the valve timing of the intake / exhaust valve.
Alternatively, the cooling water temperature T _w can be used, but the present invention is not limited to this, and the engine speed during cranking or the cam state when the engine body 1 is stopped may be used. That is, as shown in FIG. 3, the frictional force of the chain is reduced by the start of cranking, so if the start time of cranking is detected and the delay time is set starting from the start of cranking, the start can be started. Fuel can be injected at the time of returning to the hour valve timing. Also,
The cam angle sensor 1 indicates the cam state when the engine body 1 is stopped.
It is also possible to adopt a configuration in which the delay time, which is expected to be reached when the valve timing at start is reached, is variably set based on the stored cam state at the time of stop at the time of restarting.

Next, a third embodiment of the present invention will be described with reference to FIG. The feature of this embodiment is that it is applied to a V-type internal combustion engine having left and right banks.

That is, FIG. 6 is a structural explanatory view showing the overall structure of a fuel injection device for an internal combustion engine having a variable valve mechanism according to this embodiment, in which the engine body 31 is a left bank 32L.
And as a V-type engine with a right bank 32R,
Each bank 32L, 32R is provided with an independent variable valve timing device 33L, 33R, and each variable valve timing device 33L, 33R is controlled by a separate hydraulic control valve 34L, 34R. ing.

Control unit 35 according to the present embodiment
The left bank side cam angle sensor 36L and the right bank for detecting the cam angles θ _CL and θ _CR respectively changed by the left and right variable valve timing devices 33L and 33R are provided on the input side of the right bank. The side cam angle sensor 36R is connected.

In the control unit 35,
A left bank valve timing determination unit 37L that determines whether or not the left bank camshaft 2 has returned to the valve timing at the start based on the cam angle θ _CL detected by the left bank cam angle sensor 36L, and at the time of start When the valve timing is reached, the left bank side fuel injection permission unit 38L that permits the start of fuel injection on the left bank side, the right bank side valve timing determination unit 37L and the right bank side fuel injection permission unit that perform the same operation as these And 38R.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 7 shows a flowchart of the starting process according to the present embodiment. First, in step 21, the starter motor is rotated by operating the engine key to start cranking. Next, the left bank side processing of steps 23 to 24 and the right bank side processing of steps 25 to 27 are executed in parallel.

Explaining the left bank side, in step 22, the current valve timing is detected by the cam angle θ _CL detected by the left bank side cam angle sensor 36L, and in step 23, this valve timing has a small valve overlap. Monitor until the valve timing at startup is reached. When returning to the valve timing at startup,
When it is determined to be “YES” in step 23, step 2
In step 24, the start of fuel injection by the fuel injection valve 15 on the left bank side is permitted.

On the other hand, on the right bank side as well, the valve timing detected by the cam angle θ _{CR of} the right bank side cam angle sensor 36R (step 25) is monitored until it reaches the valve timing at startup (step 26), and the valve at startup is started. When the timing is reached, the start of fuel injection on the right bank side is permitted.

Therefore, when the engine body 31 is restarted in this manner, the valve timings of the left and right banks 32L and 32R are monitored independently of each other, and the engine is started first regardless of the valve timing state of the other bank. Fuel injection is started from the person who returns to the hour valve timing.

According to the present embodiment configured as described above,
Since the valve timing is independently detected for each of the left and right banks 32L and 32R, and the fuel injection is permitted from the bank which has reached the valve timing at the time of start, whichever is earlier, the engine in which the fuel is injected first is used. By increasing the rotation speed, the return time on the other bank side can be shortened as compared with the case of only cranking. Therefore, it is possible to improve the drivability by improving the exhaust performance during restart and shortening the restart time.

In each of the above-mentioned embodiments, the variable valve operating mechanism is of the variable operating center angle type which variably controls the operating center angle, as disclosed in, for example, JP-A-6-17618. A specific example of this type will be briefly described with reference to FIG. The camshaft 2 has an oil hole 4 in the axial direction.
An inner housing 42 is fixed via a bolt 41 having 1A formed, and on the outer peripheral side of the inner housing 42,
An outer housing 43 having a cam sprocket 3 formed on the base end side is arranged so as to be relatively rotatable. A first helical gear 44 and a second helical gear 45 are provided between the housings 42 and 43 so as to be movable in the axial direction. Each of the helical gears 44 and 45 is constantly urged by a return spring 46 in a direction for realizing a valve timing at the time of starting, and a hydraulic chamber 47 is defined so as to oppose the spring force of the return spring 46. . The hydraulic pressure generated by the hydraulic pump 48 is applied to the oil passage 4
9. When acting on the hydraulic chamber 47 via the oil hole 41A, the helical gears 44, 45 axially move against the spring force of the return spring 42, and this movement causes the outer housing 43 and the inner housing 42 to move. The relative rotation adjusts the operation center angle to increase the valve overlap. On the other hand, in a low load region such as during idling, the hydraulic control valve 8 opens and the hydraulic pressure in the hydraulic chamber 47 enters the oil tank (not shown) through the oil hole 41A, the oil passage 49, and the return passage 50. To escape, each helical gear 4
4, 45 are pushed back by the return springs, whereby the phase shift of the camshaft 2 is eliminated and the valve timing at the time of starting is set with a small valve overlap.

The present invention is not limited to the variable central angle type, but a variable operating angle type applying the principle of the non-constant velocity joint as described in, for example, Japanese Patent Laid-Open No. 6-185321. You may use.

Since the structure is well known in the above-mentioned Japanese Patent Laid-Open No. 6-185321 and the like, a detailed description thereof will be omitted, but this variable operating angle type has a drive shaft that rotates in synchronization with the rotation of the engine. A cylindrical cam shaft divided for each cylinder is provided on the outer peripheral side, and engaging grooves along the radial direction are formed in the flange portion on the end of the cam shaft and the flange portion on the drive shaft side, respectively. , A structure in which a pair of pins that engage with the respective engagement grooves are provided on an annular disc interposed between both flange parts, and the annular disc is rotatably held by a control housing, and the control housing is The annular disc can be made eccentric with respect to the cam shaft through the control, and the valve lift characteristic is changed by controlling the amount of eccentricity. Further, in the above-mentioned JP-A-6-185321,
A configuration using an eccentric cam is disclosed for moving the control housing in a direction perpendicular to the axis. That is, the control housing is swingably supported by the support shaft, a circular cam fitting hole is formed in the control housing, and the eccentric cam formed on the control shaft is fitted in the cam fitting hole. It is rotatably fitted. The control housing is moved by controlling the rotational position of the control shaft with an actuator. In the one described in this publication, the above-mentioned variable mechanism is applied to, for example, the intake side, and one annular disk is rotatably held by one control housing. With such a configuration, if the annular disk is concentric with the drive shaft, the camshaft rotates at a constant speed, so valve lift characteristics along the cam profile are obtained, and when the annular disk is eccentric with respect to the center of the drive shaft, It becomes a kind of non-constant velocity joint, and the camshaft rotates at a non-constant velocity with respect to the drive shaft.
The valve lift characteristic and the valve operating angle change.

Further, as described in, for example, Japanese Patent Publication No. 3-75728, a type in which two large and small cams are switched may be used. Since such a technique has already been known from the above publications, the description thereof will be omitted. In the case of this cam switching type, when the cam is switched while the oil temperature is low, there is a possibility that the oil pressure will not drop for immediate engine stall restart when the oil pressure is high and the viscosity is high. It is preferable to inject the starting fuel after detecting the valve timing.

Although the case where the variable valve mechanism is applied to the intake side camshaft 2 is shown, the invention is not limited to this, and it may be applied to the exhaust side camshaft or both camshafts. . When the variable valve mechanism is applied to both camshafts, different types of variable valve mechanism may be used.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a fuel injection control device for an internal combustion engine including a variable valve mechanism according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a process when the engine is restarted.

FIG. 3 is a timing chart showing changes over time in fuel injection timing, valve overlap, and engine speed.

FIG. 4 is a functional block diagram showing a function of a fuel injection control device for an internal combustion engine including a variable valve mechanism according to a second embodiment of the present invention.

FIG. 5 is a flowchart showing a process when the engine is restarted.

FIG. 6 is a configuration explanatory view showing an overall configuration of a fuel injection control device for an internal combustion engine equipped with a variable valve mechanism according to a third embodiment of the present invention.

FIG. 7 is a flowchart showing a process when the engine is restarted.

FIG. 8 is a cross-sectional view showing an enlarged main part of a variable valve mechanism of a central angle variable type, which is an example of a variable valve mechanism.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine main body 2 ... Camshaft (intake camshaft) 3 ... Cam sprocket 4 ... Cam 5 ... Variable valve timing device (variable valve mechanism) 9 ... Crank angle sensor 10 ... Water temperature sensor 12 ... Cam angle sensor (valve timing detection) Means) 14, 21, 35 ... Control unit 16, 22, 37L, 37R ... Valve timing determination section (valve timing determination means) 17, 23, 38L, 38R ... Fuel injection permission section (fuel injection permission means)

Claims (8)

[Claims] 1. A fuel injection control device for an internal combustion engine comprising a variable valve mechanism for variably controlling the opening / closing timing of an intake / exhaust valve, wherein the fuel is controlled when the valve timing of the intake / exhaust valve reaches a valve timing at startup. A fuel injection control device for an internal combustion engine having a variable valve mechanism, characterized in that fuel injection permission means for permitting injection is provided. 2. A fuel injection control device for an internal combustion engine comprising a variable valve mechanism for variably controlling the opening / closing timing of intake / exhaust valves, comprising valve timing detection means for detecting the valve timing of the intake / exhaust valves. Valve timing determination means for determining whether or not the detected valve timing has reached the valve timing at startup, and fuel injection permission means for permitting fuel injection when the valve timing of the intake and exhaust valves reaches the valve timing at startup A fuel injection control device for an internal combustion engine, which is provided with a variable valve mechanism. 3. A fuel injection control device for an internal combustion engine, comprising a variable valve mechanism for variably controlling the opening / closing timing of intake and exhaust valves, wherein fuel injection is permitted when a predetermined delay time has elapsed at engine startup. A fuel injection control device for an internal combustion engine, comprising a variable valve mechanism, comprising a fuel injection permission means. 4. The fuel injection control device for an internal combustion engine having a variable valve mechanism according to claim 3, wherein the delay time is set based on a parameter related to the valve timing of the intake and exhaust valves. 5. The internal combustion engine having a variable valve mechanism according to claim 4, wherein either the temperature of the working fluid for driving the variable valve mechanism or the engine coolant temperature is used as the parameter. Fuel injection control device. 6. The fuel injection control device for an internal combustion engine having a variable valve mechanism according to claim 4, wherein cranking rotation is used as the parameter. 7. The fuel injection control device for an internal combustion engine having a variable valve mechanism according to claim 4, wherein a cam state of the variable valve mechanism when the engine is stopped is used as the parameter. 8. A V-type internal combustion engine having a variable valve operating mechanism in each of the left and right banks is used as the internal combustion engine having the variable valve operating mechanism, and the start valve timing is reached first in the left and right banks. The fuel injection control device for an internal combustion engine, comprising the variable valve mechanism according to claim 1 or 2, wherein fuel injection is permitted from the bank side.