JP2000154753A - Starting control device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent wasteful consumption of a battery as well as needless elongation of time until starting of fuel injection regardless of an engine temperature and an engine condition. SOLUTION: A motor 62 cranks an engine 61. A variable valve system device 63 controls opening and closing timing of a suction valve. Suction valve closing timing at the time of engine torque sufficient for self driving is made a target value, this target value is set by a setting means 64 to the advance angle side as a cranking engine revolutionary speed is lower and an engine water temperature is lower in accordance with the cranking engine revolutionary speed and the engine water temperature, and fuel supply to the engine is prohibited by a prohibition means 65 at the time of starting the engine. A release means 68 releases fuel supply prohibition at the time when actual suction valve closing timing coincided with the target value by comparing the actual suction valve closing timing in this fuel supply prohibition condition and the target value with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine start control device.

[0002]

2. Description of the Related Art The actual compression ratio at the time of engine startup is reduced,
In order to suppress the unit vibration where the compression pressure becomes the vibration source,
There is a hybrid vehicle equipped with a decompression device (JP-A-8-28313). In this device, the engine is started by the motor with the decompression device operated, the decompression device is released when the engine speed reaches a predetermined value, and fuel injection is started when the engine reaches the starting rotation speed. ing.

[0003]

The means for reducing the actual compression ratio is not limited to the decompression device, but may be a variable valve device. Therefore, by using a variable valve operating device capable of controlling the opening / closing timing of the intake valve, by delaying the intake valve closing timing and lowering the compression ratio at the time of starting the engine, uncomfortable vibration at the time of starting the engine is reduced. (Japanese Patent Application No. 10-248276). In the proposed hybrid vehicle, when the engine stops when the oil pressure inside the engine becomes zero, the intake valve closing timing is kept at the most retarded position, which is the initial position, and when the engine starts, the oil pressure inside the engine rises. The variable valve device becomes operable, and the closing timing of the intake valve is controlled from the most retarded position to the optimal position (target value) on the advanced side.

In this case, similarly to the conventional apparatus, fuel injection is prohibited when the engine is started, and the intake valve closing timing is detected in the fuel injection prohibited state, and the detected value is used as a target value for the intake valve closing timing. At the coincident timing, it is conceivable that the prohibition of the fuel injection is released and the fuel injection is performed so that the self-sustaining operation is achieved. As the target value, the intake valve closing timing when the intake air amount sufficient for the engine to operate independently is determined.

[0005] However, if the target value is a constant value, the time (starting time) from the start of the engine to the fuel injection may be unnecessarily prolonged or the battery may be wasted. This is because it is necessary to stably output an engine torque larger than the friction torque in order to make the engine operate independently. In this case, the friction torque is affected by the engine temperature (for example, the outside temperature), and the lower the engine temperature, the greater the friction torque. Therefore, in order to increase the engine torque so that the self-sustaining operation can be performed against the friction torque which becomes larger as the temperature becomes lower, the intake valve closing timing may be advanced. That is, the lower the engine temperature, the more the target value of the intake valve closing timing is advanced. Conversely, the higher the engine temperature, the better the target value is on the retard side.

Therefore, if the target value of the intake valve closing timing is matched when the engine temperature is low, the target value is shifted when the engine temperature is higher than the matching temperature (actually, the target value may be on the retard side). At this time, there is no need to wait for the actual intake valve closing timing to reach the target value, and sufficient engine torque is generated to operate independently at a position retarded from the target value. Waiting until the time is required unnecessarily prolongs the time until fuel injection, and wastes battery consumption due to the long cranking time. Conversely, if the target value of the intake valve closing timing is matched when the engine temperature is not so low, the target value will be shifted even when the engine temperature is lower than this matching temperature. Fuel injection is started before sufficient engine torque is generated, which may cause fogging of the spark plug or wasteful fuel consumption. In order to avoid such a situation, it is necessary to start fuel injection after conditions for generating an engine torque sufficient for independent operation with respect to the engine temperature at the time of starting the engine are established.

Considering further, since the engine temperature itself rises due to the generation of frictional heat due to cranking, and the friction torque decreases accordingly, the target value of the intake valve closing timing after starting the engine is the initial value of the engine starting. It shifts to the retard side from the target value. Therefore, if the target value of the intake valve closing timing set at the start of the engine is not changed after the engine is started, the target value will shift during cranking, and the time until the start of fuel injection will be prolonged accordingly. Would.

Accordingly, the present invention employs the engine cooling water temperature and the cranking speed as factors representing the engine temperature and the engine state, and sets the target value of the intake valve closing timing in accordance with these. It is an object of the present invention to prevent the time until the start of fuel injection from being unnecessarily prolonged and prevent the battery from being wastefully consumed irrespective of the state of the engine or the state of the engine.

[0009]

According to a first aspect of the present invention, a motor 62 for cranking an engine 61 is provided as shown in FIG.
And a variable valve operating device 63 capable of controlling the opening / closing timing of the intake valve.
The target value is the intake valve closing timing when sufficient engine torque for self-sustaining operation is generated, and the target value is set to a lower value according to the cranking speed and the engine coolant temperature, as the cranking speed decreases. A means 64 for setting the advance angle as the engine water temperature is lower, a means 65 for inhibiting the supply of fuel to the engine when the engine is started, and a means 66 for detecting the actual intake valve closing timing in the fuel supply prohibited state.
Means 6 for determining whether the actual intake valve closing timing matches the target value by comparing the detected value with the target value.
7 and means 68 for canceling the fuel supply prohibition when the actual intake valve closing timing matches the target value based on the determination result.

According to a second aspect of the present invention, as shown in FIG. 10, a motor 62 for cranking an engine 61 and an intake valve closing timing at a most retarded position before the engine is started can be operated together with the generation of oil pressure inside the engine. A variable valve operating device 71 that can control the opening and closing timing of the intake valve after that, and the intake valve closing timing when engine torque sufficient for starting is generated are set as target values. A means 64 for setting the crank angle to a more advanced side as the cranking speed is lower and the engine water temperature is lower according to the engine speed and the engine water temperature, and a means 65 for prohibiting fuel supply to the engine when the engine is started. Means 66 for detecting the actual intake valve closing timing in the fuel supply prohibited state, and comparing the detected value with the target value, the actual intake valve closing timing exceeds the target value and is advanced. And determining means 72 whether, when the actual intake valve closing timing from the determination result becomes the advance side exceeds the target value, and means 73 for releasing the fuel supply prohibition.

According to a third aspect of the present invention, in the second aspect, the operating oil pressure at which the variable valve device is operable at a predetermined operating speed is determined as a predetermined value in advance, and the actual operating oil pressure P is set to the predetermined value. When P1 or less, the variable valve device is not operated, and the determination is not performed.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the rotational speed at which the self-sustaining operation can be performed is predetermined as a predetermined value Nst1, and the cranking rotational speed exceeds the predetermined value Nst1. At this time, the fuel injection is started immediately.

[0013]

According to the first and second aspects of the invention, the target value of the intake valve closing timing is set according to the engine water temperature and the cranking rotation speed. It is possible to prevent the time from the start of the engine to the start of the fuel injection (starting time) from being unnecessarily prolonged or from wasting the battery unnecessarily.

According to the third aspect, when the actual operating oil pressure is equal to or less than the predetermined value, the variable valve operating device is not in an operable state, and the intake valve closing timing is held at the initial most retarded position. As a result, the pumping loss can be reduced and the power consumption of the motor can be reduced.Furthermore, the amount of air drawn into the combustion chamber by returning to the intake pipe decreases, so that the cranking speed increases faster and the motor becomes self-sustaining. Time until operation can be shortened.

According to the fourth aspect, the time until the self-sustaining operation at the time of the hot restart can be reduced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a configuration example of a hybrid vehicle to which the present invention can be applied. This is a parallel hybrid vehicle that travels by using the power of one or both of an engine (internal combustion engine) and a motor (a rotating electric machine also serving as a generator) according to traveling conditions. In a hybrid vehicle, basically, only the motor runs in the driving range where the load is relatively small, and when the load increases, the engine is started to secure the required driving force, and if necessary, the motor and the engine are used together. The maximum driving force can be demonstrated.

In FIG. 1, a thick solid line indicates a transmission path of mechanical force, and a thick broken line indicates a power line. A thin solid line indicates a control line, and a double line indicates a hydraulic system.

The power train of this vehicle is a motor 1,
It comprises an engine 2, a clutch 3, a motor 4, a continuously variable transmission 5, a reduction gear 6, a differential gear 7, and driving wheels 8.
The output shaft of the motor 1, the output shaft of the engine 2, and the input shaft of the clutch 3 are connected to each other.
, The output shaft of the motor 4 and the input shaft of the continuously variable transmission 5 are connected to each other.

When the clutch 3 is engaged, the engine 2 and the motor 4
Is the propulsion source of the vehicle, and when the clutch 3 is released, only the motor 4 is the propulsion source of the vehicle. The driving force of the engine 2 or the motor 4 is controlled by a continuously variable transmission 5, a reduction gear 6, and a differential gear 7.
Is transmitted to the drive wheels 8 via the The continuously variable transmission 5 is supplied with pressure oil required for shifting from a hydraulic device 9. Hydraulic device 9
The oil pump (not shown) is driven by the motor 10.

The motor 1 is mainly used for starting the engine and generating power, and the motor 4 is mainly used for propulsion (powering) and braking of the vehicle. The motor 10 is for driving the oil pump of the hydraulic device 9. Further, when the clutch 3 is engaged, the motor 1 can be used for propulsion and braking of the vehicle, and the motor 4 can be used for starting the engine and generating power. The clutch 3 is a powder clutch, and can adjust the transmission torque. The continuously variable transmission 5 is a continuously variable transmission of a belt type, a toroidal type, or the like, and can continuously adjust the speed ratio.

The motors 1, 4, and 10 are driven by inverters 11, 12, and 13, respectively. When a DC electric motor is used for the motors 1, 4, and 10, a DC / DC converter is used instead of the inverter. The inverters 11 to 13 are connected to a main battery 15 via a common DC link 14,
Converts the DC charging power to AC power and
0, and converts the AC power generated by the motors 1 and 4 into DC power to charge the main battery 15. Since the inverters 11 to 13 are connected to each other via the DC link 14, the power generated by the motor during the regenerative operation can be supplied directly to the motor during the power running operation without passing through the main battery 15. it can. As the main battery 15, various batteries such as a lithium-ion battery, a nickel-metal hydride battery, and a lead battery, and an electric double layer capacitor, a so-called power capacitor, are applied.

Reference numeral 16 denotes a controller (control device).
It is equipped with a microcomputer and its peripheral parts, various actuators and the like.
It controls the rotation speeds and output torques of the transmissions 4 and 10, the speed ratio of the continuously variable transmission 5, the fuel injection amount / injection timing of the engine 2, the ignition timing and the like.

As shown in FIG. 2, the controller 16 includes an ignition key switch 20, a select lever switch 21, an accelerator pedal sensor 22, a brake switch 23, a vehicle speed sensor 24, and a battery temperature sensor 2.
5, a battery SOC detection device 26, an engine speed sensor 27, and a throttle opening sensor 28 are connected. The ignition key switch 20 closes when the ignition key of the vehicle is set to the ON position or the START position (hereinafter, the closing of the switch is called ON or ON, and the opening of the switch is called OFF or OFF). The select lever switch 21 switches P, N, R, and P in accordance with a set position of a select lever (not shown) for switching to any of the parking P, neutral N, reverse R, and drive D ranges.
One of the switches of D is turned on.

The accelerator pedal sensor 22 detects the amount of depression of the accelerator pedal, and the brake switch 23 detects the state of depression of the brake pedal (switch on at this time). The vehicle speed sensor 24 detects the running speed of the vehicle,
Battery temperature sensor 25 detects the temperature of main battery 15. The battery SOC detection device 26 detects an SOC (battery charge amount) that is a representative value of the actual capacity of the main battery 15. Further, the engine speed sensor 27 detects the speed of the engine 2, and the throttle opening sensor 28 detects the throttle valve opening of the engine 2.

The controller 16 is also connected to a fuel injection device 30, an ignition device 31, a variable valve operating device (valve timing adjusting device) 32 of the engine 2, and the like. The controller 16 controls the fuel injection device 30 to control the engine 2
In addition to adjusting the supply and stop of fuel to the fuel cell, adjusting the fuel injection amount and the injection timing, the ignition device 31 is driven to control the ignition timing of the engine 2. The controller 16 is supplied with power from a low-voltage auxiliary battery 33.

Further, the controller 16 controls the variable valve train 3
2 to control the operation state of the intake and exhaust valves of the engine 2.

Here, the variable valve operating device 32 will be described with reference to a mechanical configuration example shown in FIG. 3. This is based on the operating angle of the intake cam (cam for intake valve) 51 of the engine (valve opening period and closing period). The variable valve operating device is configured by a cam operating angle variable mechanism 50 configured to be able to change the valve timing. For example, Japanese Patent Application Laid-Open Nos. 9-242520 and 9-26.
8930 and the like, an actuator 52 that drives an eccentric shaft 53 around its axis based on a hydraulic pressure from a solenoid valve 41 controlled by a controller 16, and an eccentric shaft via a housing 54. An eccentric shaft 53 is pivoted about the rotating intake cam 51 around the axis, and the operating angle of the intake cam 51 is changed so that an intake valve (not shown) is opened. The valve opening timing and the valve closing timing can be changed stepwise or continuously between the maximum operation angle and the minimum operation angle. The operating angle of the intake cam 51 is detected by a cam rotation angle (cam phase angle) sensor 29,
Drives the solenoid valve 41 so that the intake valve actuation timing according to the engine operation state including the start-up time, and controls the operation angle of the intake cam 51.

In the present embodiment, by using this variable valve operating device, the uncomfortable vibration at the time of starting the engine is reduced by delaying the closing timing of the intake valve and lowering the compression ratio at the time of starting the engine. ing. When the engine starts, the hydraulic pressure inside the engine rises and the variable valve operating device becomes operable, and the closing timing of the intake valve is controlled from the most retarded position to the optimal position (target value) on the advanced side.

In this case, the closing timing of the intake valve when a sufficient amount of intake air for the self-sustaining operation is entered is set in advance as a target value, and fuel injection is prohibited when the engine is started. By detecting the actual intake valve closing timing, and at the timing when this detection value exceeds the target value of the intake valve closing timing and is advanced, the fuel injection prohibition is released and fuel injection is started, It is conceivable to bring the vehicle to independent operation.

However, if the target value is a constant value, the time until the start of fuel injection may be unnecessarily prolonged or the battery may be consumed needlessly. It is necessary to start fuel injection after conditions for generating an engine torque sufficient for self-sustained operation with respect to the outside air temperature at the time of starting the engine are established. In addition, it is necessary to consider that the temperature of the engine itself increases due to the cranking by the motor, and the friction torque decreases accordingly.

Therefore, the controller 16 sets a target value according to the engine water temperature and the cranking speed (the target value is set to the advanced side as the engine water temperature is lower and the cranking speed is lower).

The contents of these controls executed by the controller 16 will be described with reference to the flowchart of FIG.

FIG. 4 is for controlling the injection at the time of starting the engine, and is executed at regular intervals.

In steps 1 and 2, the state of the current ignition key switch (abbreviated as "IGN SW" in the figure) and the state of the previous ignition key switch are checked.

The current ignition key switch state is ON, and the last ignition key switch state is O.
If it is FF (i.e., when the ignition key switch is switched from OFF to ON), the process proceeds to step 3, where fuel injection is prohibited at the beginning of engine startup, and the fuel injection prohibition flag is set to 1 to end the current process. The value of the fuel injection prohibition flag is stored in the RAM.

On the other hand, when the ignition switch is
In the case of N, the process proceeds to steps 4 and 5, and the state of the current starter switch (abbreviated as “ST SW” in the figure) and the state of the previous starter switch are checked.

When the current starter switch state is ON and the previous starter switch state is OFF (that is, when the starter switch is switched from OFF to ON), the start mode start flag ("0" is set) in steps 6 and 7. (Initial setting) = 1, and after activating the counter, the process proceeds to step 8.

Here, the value of the start mode start flag is RA
Put in M and save. When the start mode start flag = 1, it is instructed to start the start mode. When the start mode is activated, another routine is activated and the engine 2
The connected motor 1 performs cranking of the engine 2 according to the motor torque command.

In the above counter, the starter switch is set to O
This is for measuring the time (cranking time) after setting N.

In steps 8 and 9, the engine speed Ne and the cooling water temperature Tw (engine water temperature) are read, and a map having the contents shown in FIG. 5 is retrieved therefrom to obtain the target cam phase angle (the target value of the intake valve closing timing). (Cam phase angle equivalent to θvcn1).

As shown in FIG. 5, the value of θvcn1 is set to the advanced side as the cooling water temperature Tw is lower and the cranking speed is lower.

In step 10, the actual cam phase angle θvc detected by the cam phase angle sensor 29 is read, and the detected value is compared with the target cam phase angle θvcn1 in step 11.

At the start of the start mode, the oil pressure inside the engine is low, and the variable valve operating device is not in an operable state.
Since the intake valve closing timing is kept at the most retarded position of the initial position, and therefore θvc ≧ θvcn1, the routine proceeds to step 12, where the value of the counter is compared with a constant value T1. Even when the variable valve apparatus operates normally, the actual cam phase angle θvc is changed from the start of cranking to the target cam phase angle θvcn.
A predetermined delay time is required before the value becomes greater than 1 to advance to the advance side, but the constant value T1 is a value much larger than this delay time. Therefore, when the variable valve operating device operates normally, the value of the counter does not exceed the fixed value T1, and the current process is terminated as it is.

When the cranking rotation speed is increased by the start of the start mode, the oil pump in the engine is activated by the operation of the engine driven oil pump, the hydraulic pressure in the engine is raised, and the variable valve system becomes operable. It moves from the most retarded position to the target value. In other words, the actual cam phase angle θvc moves to the target cam phase angle θvcn1. Therefore, when the actual cam phase angle θvc eventually advances beyond the target cam phase angle θvcn1 (θvc <θvcn1), the routine proceeds to step 13, where the prohibition of fuel injection is canceled (fuel injection prohibition flag). = 0).

With the fuel injection prohibition flag = 0, another routine operates to calculate the fuel injection amount at the start, and the fuel injection is started in synchronization with the engine rotation based on the start injection amount. According to the intake valve closing timing at this time, the amount of intake air sufficient for the self-sustained operation is input, so that the engine starts the self-sustained operation immediately at the start of the fuel injection.

On the other hand, in step 11, θvc ≧ θv
In the case of cn1, when the value of the counter exceeds a certain value T1, that is, when a certain time has elapsed without the actual cam phase angle θvc exceeding the target cam phase angle θvcn1 and being on the advance side, the variable valve actuation is performed. It is determined that there is a failure (failure) in the device, and the process proceeds from step 12 to step 14,
After turning on (or blinking) the warning lamp in the vehicle cabin, the current process is terminated. The warning lamp is for notifying the driver of a malfunction of the variable valve operating device.

FIG. 6 shows a second embodiment, which corresponds to FIG.
This corresponds to the first embodiment. The same steps as those in FIG. 4 are denoted by the same step numbers. Whereas the first embodiment does not consider the operating oil pressure of the variable valve operating device, this embodiment considers the operating oil pressure.

4 will be described mainly. In step 21, a predetermined value Nst1 is obtained by searching a table containing the contents of FIG. 7 from the cooling water temperature Tw, and the predetermined value Nst1 is compared with the actual engine speed. The number Ne is compared in step 22.

Here, the predetermined value Nst1 is (the lowest value of) the number of revolutions at which the self-sustaining operation is possible. Therefore, Ne> Ns
When it is t1, since it is possible to perform the self-sustaining operation without determining whether the actual cam phase angle θvc has advanced to the advance side beyond the target cam phase angle θvcn1, the fuel injection is immediately performed. Therefore, the routine proceeds to step 13, where the fuel injection prohibition flag is set to zero.

Here, as shown in FIG. 7, the value of Nst1 increases as the cooling water temperature Tw decreases.

On the other hand, if Ne ≦ Nst1, the routine proceeds to steps 23 and 24, where the actual operating oil pressure P
(Detected by a sensor), and compares the actual working oil pressure P with a predetermined value P1.

Here, the predetermined value P1 is (the minimum value of) the hydraulic pressure sufficient to operate the variable valve operating device at a predetermined speed. Therefore, when P> P1, it is determined that the variable valve operating device is in an operable state, and the process proceeds to step 9 and thereafter.

On the other hand, when P ≦ P1, sufficient hydraulic pressure has not risen and the variable valve operating device is not in an operable state (that is, the intake valve closing timing is the initial position, the most retarded angle). Position), and proceeds to the processing of step 12.

The flowcharts in FIGS. 4 and 6 are as follows.
When the hybrid vehicle is driven, it is configured only for the first engine start. Actually, the engine is stopped when it is not necessary even during driving of the vehicle, and then it is necessary to restart the engine. However, when the engine is restarted, the engine is started in the same manner as in FIGS. Injection control may be performed.

Here, the operation of each of the above-described two embodiments will be described with reference to FIG. 8. FIG. 8 is a graph in which operating points are traced on the characteristics shown in FIG. In detail, a → b
The broken line connected to → b ′ is a trace of the operating point in the case of the first embodiment, and c → d, c →
The broken lines connecting e, c → f and c → g are obtained by tracing the operating points in the case of the second embodiment. The dashed line indicated by α in the figure is a line following the cranking rotation speed immediately after the start of the engine corresponding to the cooling water temperature at the start, and the lower the cooling water temperature at the start, the more the cranking immediately after the engine starts. The speed is low.

<1> In the case of the first embodiment The operating point follows a → b → b ′ when the engine is started at a very low temperature. For cooling water temperature that does not rise immediately, the cranking speed easily rises,
The operating point moves almost directly above the point a.

However, the target cam phase angle θvcn1 cannot be set until the operating point reaches the point b which intersects the line at the most advanced position (because it is not possible to advance beyond the most advanced position). , The most advanced position is set as the target cam phase angle θvcn1. The cranking speed further rises, and the cooling water temperature rises in response to the rise in the speed, so that the operating point rises with a gentle curve from b. In the process of moving the operating point in this way, the target cam phase angle θvcn1 is updated to the retard side, but the oil pump operates by cranking,
Eventually, when the variable valve operating device becomes operable and the actual cam phase angle moves to the advance side beyond the target cam phase angle θvcn1 (point b ′), fuel injection is started, and the engine starts at this timing. Enter autonomous operation.

<2> In the case of the second embodiment When the engine is started at a low temperature, the cranking rotational speed increases, for example, almost immediately above the point c. It is assumed that the actual operating oil pressure P at the start of cranking is equal to or less than a predetermined value P1.

If the operating point follows c → d: This is the normal case. In the process of moving the operating point from the point c, when the actual operating oil pressure P exceeds the predetermined value P1 due to the operation of the oil pump due to cranking (the variable valve gear is in an operable state), the target cam phase angle θvcn1 Is set for the first time, and thereafter, the target cam phase angle θvcn1 is updated to the retard side, but the actual cam phase angle moves beyond the target cam phase angle θvcn1 to the advance side by the operation of the variable valve operating device. At this time (point d), fuel injection is started, and the engine enters into an independent operation.

If the operating point follows c → e:
Actual working oil pressure P despite cranking
Is longer than the predetermined value P1, and when the actual cam phase angle moves to the advanced side beyond the target cam phase angle θvcn1 which is the most advanced position (point e), the fuel injection is started. is there.

If the operating point follows c → f:
This is the case where the battery capacity decreases during cranking, and the cranking speed decreases halfway. Also in this case, the target cam phase angle value θvcn1 is set for the first time at the timing when the actual operating oil pressure P exceeds the predetermined value P1, and the actual cam phase angle exceeds the target cam phase angle θvcn1 by the operation of the variable valve operating device. When moving to the advance side (f
Point), fuel injection is started.

If the operating point follows c → g:
Is a case where the actual operating oil pressure P has not exceeded the predetermined value P1. At this time, when the value of the counter exceeds the fixed value T1 (point g), it is determined that a failure has occurred in the variable valve operating device, and the warning lamp is turned on. No fuel injection is performed.

When the operating point is h: This is the same state as when the engine itself has been completely warmed up, such as when the engine is stopped immediately after the engine has been warmed up but restarted immediately (ie, at the time of hot restart). Is the case.
At this time, since the rotation speed at the start of cranking exceeds the predetermined value Nst1, which is the rotation speed at which the self-sustaining operation can be performed, the fuel injection is started immediately, and the engine enters the self-sustaining operation.

As described above, in the two embodiments, the target cam phase angle θvcn1 corresponding to the target value of the intake valve closing timing is set in accordance with the engine water temperature and the cranking speed (the lower the cooling water temperature, (The lower the number of revolutions, the more the angle is set to the advanced side.) Prevents the time from engine startup to fuel injection from being unnecessarily prolonged or wasting battery power, regardless of the outside air temperature and engine condition. it can.

When the actual cam phase angle exceeds the target cam phase angle and is not on the advance side even if the counter value exceeds the fixed value T1, a warning lamp in the vehicle compartment is turned on. In addition, the driver can be informed that a problem has occurred in the variable valve operating device.

In particular, according to the second embodiment, the intake valve closing timing is held at the most retarded position, which is the initial position, until the actual operating oil pressure P of the variable valve operating device exceeds the predetermined value P1. Motor power consumption can be reduced by reducing pumping loss, and the amount of air drawn into the combustion chamber by returning to the intake pipe is reduced. Time can be shortened.

According to the second embodiment, the engine speed is a predetermined value N which is a speed at which the engine can be operated independently.
When the time exceeds st1, the fuel injection is started immediately, so that the time until the self-sustaining operation at the time of the hot restart can be shortened.

In the embodiment, the hybrid vehicle in which the engine 2 and the motor 1 are always connected has been described. However, the present invention is not limited to this, and the present invention can be applied to a normal vehicle in which the driving source is only the engine. There are applications. The engine is applicable not only to a normal engine but also to a lean burn engine or a direct fuel injection type spark ignition engine.

In the embodiment, the case where the cam phase angle corresponding to the intake valve closing timing is detected has been described, but the intake valve closing timing may be directly detected.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a configuration example of a hybrid vehicle to which the present invention can be applied.

FIG. 2 is a block diagram of a controller.

FIG. 3 is a schematic configuration diagram of an embodiment of a variable valve operating device.

FIG. 4 is a flowchart for explaining start-time injection control according to the first embodiment;

FIG. 5 is a characteristic diagram of a target value.

FIG. 6 is a flowchart illustrating start-time injection control according to a second embodiment.

FIG. 7 is a characteristic diagram of a predetermined value Nst1.

FIG. 8 is a waveform chart for explaining the operation of the present invention.

FIG. 9 is a diagram corresponding to claims of the first invention.

FIG. 10 is a diagram corresponding to claims of the second invention.

[Explanation of symbols]

 Reference Signs List 1 motor 2 engine 16 controller 29 cam phase angle sensor 32 variable valve operating device 50 cam operating angle variable mechanism

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 41/06 320 F02D 41/06 320 330 330 J 41/32 41/32 D // B60K 6/00 B60K 9 / 00Z 8/00 F term (reference) 3G084 AA00 BA13 BA23 CA01 DA02 EA11 EB08 EB12 FA00 FA20 FA33 3G092 AA11 AC02 BB06 BB10 DA01 DA09 DD01 DG05 EA03 EA09 EA14 EA15 EA17 FA25 FA31 FA43 GA01 HA13Z HA13A09 HE01 AA16 AB00 BA19 BA24 CA01 DA00 DA01 DA05 DA12 EA05 EC02 FA11 FB00 FB01 FB02 FB05 3G301 HA04 HA15 HA19 JA02 JB10 KA01 LB04 MA24 MA25 NA08 NC02 NE11 PA11Z PB03Z PC10Z PE01Z PE08Z PE10A PE10Z PF01ZPFZ PF01ZPFZ

Claims (4)

[Claims] 1. A motor for cranking an engine, a variable valve operating device capable of controlling an opening / closing timing of an intake valve, and a target value for setting a closing timing of an intake valve when an engine torque sufficient for independent operation is generated. Means for setting the target value to an advanced side as the cranking speed is lower and the engine water temperature is lower according to the cranking speed and the engine water temperature. Means for inhibiting, means for detecting the actual intake valve closing timing in the fuel supply prohibited state, and whether or not the actual intake valve closing timing matches the target value by comparing the detected value with the target value And a means for canceling the prohibition of fuel supply when the actual intake valve closing timing matches the target value based on the result of the determination. 2. A motor for cranking the engine, and before the engine is started, the intake valve closing timing is at the most retarded position, and is operable with the generation of oil pressure inside the engine, and thereafter, the opening and closing timing of the intake valve is controlled. The variable valve gear to be obtained and the intake valve closing timing when sufficient engine torque is generated for starting are set as target values, and this target value is set to a low cranking speed according to the cranking speed and the engine coolant temperature. Means for setting the advance angle as the engine water temperature is lower, means for inhibiting fuel supply to the engine when the engine is started, and means for detecting the actual intake valve closing timing in the fuel supply prohibited state. Means for determining whether or not the actual intake valve closing timing has advanced beyond the target value by comparing the detected value with the target value; When the closing timing becomes the advance side exceeds the target value, start control system for an engine characterized in that it comprises a means for releasing the fuel supply prohibition. 3. An operating oil pressure at which the variable valve operating device is operable at a predetermined operating speed is determined in advance as a predetermined value, and when the actual operating oil pressure is equal to or less than the predetermined value, the variable valve operating device is controlled. 3. The engine start control device according to claim 2, wherein the determination is not performed without operating the engine. 4. The fuel injection system according to claim 1, wherein a rotation speed at which the self-sustaining operation can be performed is determined in advance as a predetermined value, and when the cranking rotation speed exceeds the predetermined value, fuel injection is started immediately. The engine start control device according to any one of the above.