JP2001263117A - Vehicle with automatic stop engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely perform the control of an intake valve to the most lagged position in the stop of an engine and the learning of the most lagged position in a vehicle with automatic stop engine. SOLUTION: This vehicle comprises a variable valve system for changing the intake valve operating timing of the engine and a cam position detecting sensor for detecting the intake valve operating timing. An instruction is given to the variable valve system in an engine stop command to control the intake valve closing timing to the most lagged position, the intake valve closing position at the most lagging is learnt on the basis of the detection result of the intake valve closing position in the engine stop, and the intake valve operating timing is controlled on the basis of the learning result. The engine stop command surely moves the intake valve closing timing to a desired most lagged position by delaying it for a prescribed time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle for automatically stopping an engine, and more particularly to a technique for controlling valve timing when an engine is stopped by a variable valve operating device.

[0002]

2. Description of the Related Art There is known a variable valve operating apparatus that changes the valve timing of an engine in accordance with an operating state. In an engine equipped with a variable valve operating device, fuel efficiency, output, startability, and the like can be improved by variable control of valve timing.
No. 3). In order to ensure the effect of such a variable valve operating device, it is necessary to accurately control the positions of the intake and exhaust valves with high response by learning control.

On the other hand, there is known a vehicle in which an engine is automatically stopped when the vehicle is stopped as a measure against the environment and fuel consumption. When a variable valve operating device is provided in this type of vehicle, vibration can be reduced by automatically setting the intake valve closing timing to the most retarded position that is later than during operation when the engine is automatically stopped or started.

However, in this case, since the intake valve closing timing is controlled to the most retarded position only when the engine is stopped or thereafter, the most retarded position is learned by ordinary learning control. There is no opportunity, and therefore, there arises a problem that the deviation of the operation timing due to the deterioration with time of the variable valve operating device cannot be accurately corrected. In addition, when the engine is stopped, the control to the most retarded position is started in a state where the rotation speed is reduced. In some cases, the engine is stopped, and as a result, vibration occurs.

The present invention has been made in view of such a problem, and has as its object to reliably control the intake valve to the most retarded position and learn the most retarded position when the engine is stopped. I have.

[0006]

According to a first aspect of the present invention, there is provided an automatic engine stop vehicle provided with stop command means for commanding an engine stop to an engine control system under predetermined operating conditions. A variable valve operating device for changing the valve timing, intake valve position detecting means for detecting an intake valve operating timing, and controlling the intake valve closing timing to the most retarded position by instructing the variable valve operating device at the time of the engine stop instruction. A valve timing control unit that learns the intake valve closing position at the most retarded angle based on the detection result of the intake valve closing position when the engine is stopped, and controls the intake valve operating timing based on the learning result;
Stop instruction delay means for delaying the engine stop instruction for a predetermined time and outputting the delayed instruction to an engine control system.

[0007] A second invention is the first invention, wherein
The valve timing control means and the stop command delay means are configured to perform learning of the intake valve closing position at the most retarded angle and delay of the engine stop command only at the first engine stop command after the operation of the vehicle is started. To be configured.

In a third aspect of the present invention, the stop command delay means of the first aspect of the present invention comprises the step of setting the intake valve closing position to a predetermined reference value other than the first engine stop command after the operation of the vehicle is started. Also output an engine stop command to the engine control system when the vehicle moves to the retard side.

In a fourth aspect based on the second or third aspect, the variable valve device is configured to continuously and variably control the phase of the camshaft with respect to the engine crankshaft by hydraulic pressure.

In a fifth aspect based on the first or second aspect, the stop command delay means is configured to variably set a delay time according to the engine operating state before the stop command.

In a sixth aspect based on the second or third aspect, the vehicle with the engine automatically stopped includes a first rotating electric machine that starts the engine and generates power, and a second rotating electric machine that generates a driving force. As a hybrid vehicle equipped with

[0012]

According to the first aspect of the present invention, when an engine stop command is issued, a command is issued to the variable valve apparatus to set the intake valve closing timing to the most retarded position, while the engine stop command is issued for a predetermined delay time. It is given to the engine control system after the elapse. Since the engine continues to operate during this delay time, the variable valve operating system reliably moves the intake valve closing timing to the most retarded position. Therefore, it is possible to reliably prevent the occurrence of vibration when the engine is stopped, to learn the most retarded position of the intake valve closing timing, and to accurately control the intake valve operating position by the variable valve operating device thereafter. it can.

According to the second invention, the learning of the intake valve closing position at the most retarded angle and the delay of the engine stop command are performed only at the time of the first engine stop command after the operation of the vehicle is started. It is possible to avoid the prolongation of the engine operation time due to the stop delay when the engine is stopped. The purpose of learning the most retarded position of the intake valve is to compensate for phase fluctuations of the variable valve operating device due to deterioration over time. It only needs to be performed when the engine is stopped. After the learning of the most retarded position is completed, the closed position of the intake valve can be reliably moved to the most retarded position. Therefore, as shown in the third invention, the closed position of the intake valve when the engine is stopped is stopped. By transmitting an engine stop command to the engine control system after waiting for the motor to move to the retard side from the predetermined reference value, the object of vibration reduction can be achieved.

As shown in the fourth aspect of the present invention, a variable valve operating device that continuously and variably controls the phase of a camshaft with respect to an engine crankshaft by means of oil pressure has the effect of hydraulic system leakage and oil deterioration. Therefore, learning of the most retarded position provided with the delay time according to the present invention is particularly effective.

On the other hand, the delay time for performing the learning is as follows:
In addition to setting this as a fixed value, as shown in the fifth invention, it may be variably set according to the operating state before the engine stop command, for example, the water temperature or the oil temperature.
For example, in the above-mentioned hydraulic variable valve device, the operating speed to the most retarded position may change depending on the oil temperature.
By detecting the oil temperature and setting the delay time, it is possible to optimize so that the time until the engine is stopped is always minimized.

In the hybrid vehicle described as the sixth aspect of the present invention, not only when the vehicle is stopped but also when the engine is stopped and restarted under various operating conditions determined by control such as when the vehicle is driven only by the motor. Is performed, the engine is frequently stopped during the operation of the vehicle. Therefore, in such a hybrid vehicle, the effect of reliably suppressing the vibration when the engine is stopped by learning the most retarded position of the intake valve greatly contributes to increasing the comfort of the vehicle.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the above invention is applied to a hybrid vehicle will be described below with reference to the drawings.
In FIG. 1, the power train of this hybrid vehicle includes a motor 1, an engine 2, an electromagnetic 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 motor 1 and the motor 4 correspond to the first rotating electric machine and the second rotating electric machine, respectively.

The motor 1 and the engine 2 are connected to each other via a speed reducer (not shown) having a predetermined rotation ratio so that they can be driven mutually. The output shaft of the clutch 3, the output shaft of the motor 4, and the continuously variable transmission are provided. The input shafts of the machine 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 Pressure oil is supplied from the hydraulic device 9 to the continuously variable transmission 5 to clamp and lubricate the belt.

The motor 1 is mainly used for starting the engine and generating power, and the motor 4 is mainly used for power running and regenerative operation at the time of deceleration. The motor 10 is for driving the oil pump of the hydraulic device 9. However, when the clutch 3 is engaged, the motor 1 can be used for powering and braking of the vehicle,
The motor 4 can be used for starting the engine or generating power.

The motors 1, 4, and 10 are driven by inverters 11, 12, and 13, respectively. Inverter 11
To 13 are high-power batteries 1 via a common DC link 14.
5, the DC power of the high-power battery 15 is converted into AC power and supplied to the motors 1, 4, and 10, and the AC power generated by the motors 1 and 4 is converted into DC power to convert the high-power battery 15 into DC power. Charge. The inverters 11 to 11
Since the motors 13 are connected to each other via the DC link 14, the power generated by the motor in the regenerative operation can be supplied directly to the motor in the power running operation without passing through the high-power battery 15.

Reference numeral 16 denotes a controller having the function of each means of the control system of the present invention. The controller 16 includes a microcomputer and its peripheral devices, various actuators, and the like.
Transmission torque, the number of rotations and output torque of the motors 1, 4, and 10, the speed ratio of the continuously variable transmission 5, the fuel injection amount of the engine 2,
It controls the injection timing, ignition timing, intake valve operation timing, and the like.
The controller 16 is supplied with power from a low-voltage auxiliary battery 33.

As shown in FIG. 2, the controller 16 includes a key switch 20, a select lever switch 21,
Accelerator pedal sensor 22, brake switch 23, vehicle speed sensor 24, battery temperature sensor 25, battery SO
The C detector 26, the crank angle sensor 27, and the throttle opening sensor 28 are connected.

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. Vehicle speed sensor 24
Detects the running speed of the vehicle, and the battery temperature sensor 25 detects the temperature of the high-power battery 15. The battery SOC detection device 26 detects an SOC (State Of Charge) that is a representative value of the actual capacity of the high-power battery 15. The crank angle sensor 27 detects the rotation speed of the engine 2, and the throttle opening sensor 28 detects the throttle valve opening of the engine 2.

The controller 16 further includes an engine 2
Fuel injection device 30, ignition device 31, variable valve operating device 32
Are connected. The controller 16 controls the fuel injection device 30 to supply and stop the fuel to the engine 2 and adjust the fuel injection amount and the injection timing.
1 is driven to control the ignition timing of the engine 2, while controlling the operation timing of the intake valve of the engine via the variable valve device 32. Further, the controller 16 has a function of controlling the stop and restart of the engine 2 under predetermined conditions according to the vehicle operating state. In this case, by stopping the fuel supply by the fuel injection device 30, Engine 2
When the engine 2 is stopped and the stopped engine 2 is restarted, the starting cranking is performed by the motor 1 and the fuel supply to the fuel injector 30 is restarted.

FIG. 3 schematically shows an example of the variable valve operating device 32. In the figure, a piston 44 is fitted between an inner cylinder 42 attached to a shaft end portion of an intake camshaft 41 and an outer cylinder 43 surrounding the inner cylinder 42. A retard-side oil chamber 45a and an advance-side oil chamber 45b are defined. The piston 44 is connected to the inner cylinder 42 or the outer cylinder 4
3, the inner cylinder 42 and the outer cylinder 43 rotate relative to each other when the piston 44 moves in either the left or right direction in the figure. A cam sprocket (not shown) for transmitting the engine rotation to the intake camshaft 41 is attached to the outer cylinder 43, so that the intake camshaft 41 changes its phase with respect to the engine crankshaft according to the position of the piston 44.

The position of the piston 44 is controlled by the oil pressure supplied to the front and rear oil chambers 45a or 45b. In the figure, reference numeral 51 denotes a valve device for controlling the hydraulic pressure supply, which mainly comprises a spool 52 for switching the hydraulic pressure supply direction and a solenoid 53 for controlling the position of the spool 52.

When the spool 52 is driven to the left in the drawing, the engine oil pressure from the main gallery 54 is applied to the retard oil chamber 4 via the port c at the center of the spool and the retard oil passage 55a.
5a. At this time, the advance side oil chamber 45b is simultaneously connected to the drain passage 56 via the advance side oil passage 55b and the port b on the right side of the spool. This allows the piston 4
4 moves to the left, and the intake camshaft 41 rotates in the retard direction. On the contrary, when the spool 52 is driven rightward, the engine oil pressure from the main gallery 54 is introduced into the advance-side oil chamber 45b through the port c at the center of the spool and the advance-side oil passage 55b. The retard-side oil chamber 45a is connected to the drain passage 56 via the retard-side oil passage 55ba and the port a on the left side of the spool, whereby the piston 44 moves rightward and rotates the intake camshaft 41 in the advance direction. Let it.
In the illustrated state where the spool 44 is in the neutral position, each oil passage 54
a, b and oil chambers 45a, b are any ports a, b, c
Piston 4
4 and the intake camshaft 41 are fixed at the position at that time.

The control of the operation timing of the intake valve by the variable valve operating device 32 is performed based on a signal from a cam position detecting sensor 57 functioning as an intake valve position detecting means.
The solenoid 53 is set so that 6 is set to a predetermined intake valve operation timing.
Is driven to perform feedback control. This corresponds to the reference position signal (REF
Signal) as a trigger, the rotation angle is counted until the cam target signal from the cam position detection sensor 57 is input, and the actual value of the intake camshaft 41 is calculated from the difference between the count result ca and a predetermined cam reference position. The position is detected (see the sensor signal section in FIG. 3). The controller 16 drives the valve device 51 by PI control so that the actual cam position thus obtained becomes the target position. At this time, a dither signal is superimposed on the valve drive signal in order to remove the dead zone of the valve device 51 and enhance the response (see the control signal section in FIG. 3).

The above is a basic configuration example of a hybrid vehicle to which the present invention can be applied. In the present invention, for example, in a vehicle having such a variable valve operating device 32 and an automatic engine stop function, It is an object of the present invention to reliably control the intake valve closing position to a predetermined most retarded position when stopping and to learn the most retarded position. Hereinafter, embodiments of the control contents of the controller 16 for this purpose will be described with reference to the drawings.

FIGS. 4 and 5 are flow charts showing the outline of the control from the control of the intake valve closing position to the most retarded position by the variable valve operating device 32 in response to the engine stop command and the subsequent stop of the engine. This control is periodically and repeatedly executed as part of comprehensive control of the hybrid vehicle.

In this control, first, various operation parameters are read through the above-described sensors or switches, and
Next, it is determined whether there is an engine stop command (step 4).
01, 402). If there is no engine stop command, the current process ends. If an engine stop command is issued, then the target closing timing TGVTC of the intake valve is set to the most retarded angle (in this case, zero)
And the variable valve gear 32 so that the target closing timing is reached.
Is driven (step 403).

Next, it is determined whether or not the engine stop command is the first engine stop command after the start of vehicle operation (step 404). Although not shown, this can be determined by setting a flag that is set by, for example, an ON operation of a key switch and reset by the end of learning, which will be described later. If it is the first engine stop command, the engine stop command is made effective after performing the learning process of the intake valve closing timing, and fuel injection and ignition are stopped (steps 407 and 406). Step 404
If it is determined that is not the first engine stop command at this time, it is after the learning process of the intake valve closing timing has already been completed, and the intake valve closing timing definitely moves toward the most retarded position. Therefore, the engine stop command is made valid after waiting for the intake valve closing timing VTC to become less than the predetermined reference value THVTC1 without performing the learning process again (steps 405 and 406).

FIG. 5 shows the details of the learning process. In this process, first, it is determined from the engine speed NE whether or not the variable valve operating device 32 is in a state where the intake valve closing timing can be reliably moved to the predetermined most retarded position (step 501).
If the engine rotation speed NE is equal to or higher than the predetermined reference value THNE1, the variable valve operating device 32 is determined to be operable, and the process proceeds to learning processing after step 502. Is determined to be inoperable and returns to the processing of FIG. 4 without performing the learning processing (step 507). In addition,
In this determination, not only the engine speed but also the engine oil pressure is detected by, for example, a pressure sensor, and learning may be started on condition that the oil pressure is equal to or more than a predetermined value.

If it is determined in step 501 that learning is possible, a delay timer for delaying the time until the next engine stop is initialized. This timer is a down-count timer, and starts learning when the timer value becomes zero in the subtraction processing from the initial value TDL (step 50).
2,503,504). During this delay processing, the phase of the intake cam 41 is moved to the most retarded position by the variable valve operating device 32.

In the learning process of the most retarded position of the intake valve closing timing, first, a deviation BASOFS between the cam position VTCPOS detected by the above-described signal from the cam position detection sensor 57 and the reference position BASANG # is obtained (step 505). The learning value BASLRN (= BASANG # -BASOFS) obtained from these is updated as the learning value of the intake valve most retarded position (step 506). Thereby, the closing timing of the intake valve can be promptly controlled to the predetermined most retarded position in accordance with the state of the variable valve operating device 32 at that time.

By repeating the above processing, when the engine is stopped, the variable valve operating device 32 quickly controls the intake valve closing timing to the desired most retarded position, so that the vibration when the engine is stopped is reliably reduced. By learning the most retarded position, it is possible to accurately control the subsequent intake valve operation timing. Further, in this embodiment, since the learning process is performed only at the time of the first engine stop at the start of the vehicle operation, the opportunity to delay the engine stop for learning can be minimized.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram of a control system of the hybrid vehicle.

FIG. 3 is a schematic explanatory view of a variable valve operating device.

FIG. 4 is a first flowchart showing one embodiment of control according to the present invention.

FIG. 5 is a second flowchart showing one embodiment of control according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 motor (rotary electric machine) 2 engine 3 electromagnetic clutch 4 motor (rotary electric machine) 5 continuously variable transmission 9 hydraulic device 10 hydraulic pressure generating motor 15 battery 16 controller 20 key switch 21 select lever switch 22 accelerator pedal sensor 23 brake switch 24 vehicle speed Sensor 25 Battery temperature sensor 26 Battery SOC detecting device 27 Crank angle sensor 28 Throttle opening sensor 32 Variable valve operating device 41 Intake camshaft 51 Valve device 57 Cam position detection sensor (intake valve position detection means)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 29/02 321 F02D 29/02 321A 29/06 29/06 D // B60K 6/02 B60K 9/00 EF term (reference) 3G018 AA14 AB02 AB16 BA29 BA33 CA12 DA20 DA70 EA12 EA20 EA32 FA01 FA07 GA32 3G092 AA01 AA11 AC03 BB01 BB06 CA02 DA03 DA10 DF05 DG09 EA02 EA04 EA16 EA25 EC05 FA14 FA30 GA10Z10 HA10Z10Z10 HA10Z10 HA10 3G093 AA01 BA22 BA33 CA02 CA04 CB01 CB04 DA06 DA07 DA13 DB06 DB11 EA15 EC01 FA09 FA12 FB02 FB04 5H115 PA01 PA05 PG04 PI16 PI21 PU01 PU26 PV09 QE12 QI04 QN03 QN05 QN13 QN22 QN23 TE03 TE06 TI10

Claims (6)

[Claims] 1. A variable valve train for changing the operation timing of an intake valve of an engine in an automatic engine stop vehicle having a stop command means for commanding an engine control system to stop the engine under predetermined operating conditions; Intake valve position detecting means for detecting a valve operation timing, and controlling the intake valve closing timing to the most retarded position by instructing the variable valve operating device at the time of the engine stop instruction, and controlling the intake valve closing position when the engine is stopped. Valve timing control means for learning the intake valve closing position at the most retarded angle based on the detection result, and controlling the intake valve operation timing based on the learning result; and an engine control system for delaying the engine stop command for a predetermined time. Automatic stop vehicle provided with stop command delay means for outputting to the engine. The valve timing control means and the stop command delay means each learn the intake valve closing position at the most retarded angle only at the time of the first engine stop command after the operation of the vehicle has started, and provide the engine stop command. The vehicle with the engine automatically stopped according to claim 1, wherein the vehicle is delayed. 3. The stop command delay means, when the engine stop command is not issued for the first time after the operation of the vehicle is started, when the intake valve closing position moves to the retard side from a predetermined reference value. 2. The vehicle according to claim 1, wherein a stop command is output to an engine control system. 4. The vehicle according to claim 2, wherein the variable valve train is configured to continuously and variably control the phase of the camshaft with respect to the engine crankshaft by hydraulic pressure. 5. The vehicle according to claim 1, wherein the stop command delay means variably sets a delay time according to an engine operating state before the stop command. 6. An automatic engine stop vehicle includes a first rotating electric machine that starts an engine and generates electric power, and a second rotating electric machine that generates a driving force.
The engine automatic stop vehicle according to any one of claims 2 and 3, wherein the vehicle is configured as a hybrid vehicle including: