WO2014054676A1

WO2014054676A1 - Hybrid vehicle control device

Info

Publication number: WO2014054676A1
Application number: PCT/JP2013/076789
Authority: WO
Inventors: 崇一折田; 奈月中倉
Original assignee: 日産自動車株式会社
Priority date: 2012-10-03
Filing date: 2013-10-02
Publication date: 2014-04-10
Also published as: JP2015231749A

Abstract

In this hybrid vehicle control device, when the ignition switch is switched off and a valve timing changing means is not in a prescribed advanced position, stopping of the vehicle system is delayed, and in a state in which the engine fuel injection has stopped, rotation of the engine is maintained by the motor, the valve timing changing means is changed to the prescribed advanced position and locked, and thereafter the vehicle system is stopped.

Description

Control device for hybrid vehicle

The present invention relates to a control apparatus for a hybrid vehicle that includes an engine and a motor as power sources and includes a valve timing changing mechanism that can change the valve timing of the engine.

As a valve timing control device for an engine, a technique described in Patent Document 1 is disclosed. This publication includes a valve timing changing mechanism that operates using an oil pump that is driven by the driving force of the engine as a hydraulic pressure source. When the ignition switch is turned off, the valve timing is set to a predetermined advance position (most retarded position). Therefore, the valve timing changing mechanism is activated by delaying the engine stop for a predetermined time in order to move and lock to a position substantially intermediate between the most advanced angle position and slightly closer to the advanced angle position.

JP 2011-179418 A

However, when moving to a predetermined advance position when the ignition switch is off, if the amount of movement to the advance position is large, the predetermined time for delaying the engine stop may become longer. This means that the engine ignition state continues even though the ignition switch is turned off, which makes the driver feel uncomfortable. Also, there are cases where the engine is stopped with the ignition switch turned on as in a hybrid vehicle, and even if the ignition switch is turned off in that state, the engine is stopped, so the valve timing changing mechanism can be operated. Can not.

The present invention has been made paying attention to the above problem, and an object of the present invention is to provide a control device for a hybrid vehicle that can move the valve timing to a predetermined position when the system is stopped without causing the driver to feel uncomfortable. .

In order to achieve the above object, in the hybrid vehicle control device of the present invention, when the ignition switch is turned off and the valve timing changing means is other than the predetermined advance position, the stop of the vehicle system is delayed, and the engine In the state where the fuel injection is stopped, the rotation of the engine is maintained by the motor, the valve timing changing means is changed to the predetermined advance position and locked, and then the vehicle system is stopped.

Therefore, since the fuel injection is stopped and the engine speed is maintained by the motor, the valve timing changing means can be advanced without causing the driver to feel uncomfortable.

1 is an overall system diagram illustrating a hybrid vehicle according to a first embodiment. 3 is a flowchart illustrating a valve timing control process executed in the hybrid vehicle control apparatus according to the first embodiment. 3 is a time chart showing a valve timing control process executed when the engine is operated in the hybrid vehicle control apparatus of the first embodiment. 4 is a time chart showing a valve timing control process executed when the engine is stopped in the hybrid vehicle control apparatus according to the first embodiment.

E engine
CL1 1st clutch
MG motor generator
CL2 2nd clutch
CVT belt type continuously variable transmission 1 engine controller 2 motor controller 5 first clutch controller 6 second clutch controller 7 CVT controller 8 range position sensor 9 ignition switch 10 integrated controller
IVC valve timing change mechanism
OP1 IVC pump
OP2 Transmission pump

First, the drive system configuration of the hybrid vehicle will be described. FIG. 1 is an overall system diagram illustrating a hybrid vehicle according to a first embodiment. As shown in FIG. 1, the drive system of the hybrid vehicle in the first embodiment includes an engine E, a first clutch CL1, a motor generator MG, a second clutch CL2, a belt type continuously variable transmission CVT, and a propeller shaft. It has PS, differential gear DF, left drive shaft DSL, right drive shaft DSR, left front wheel FL (drive wheel), and right front wheel FR (drive wheel).

The engine E is, for example, a gasoline engine, and the valve opening degree of the throttle valve is controlled based on a control command from the engine controller 1 described later. Further, the engine E is provided with a valve timing changing mechanism IVC capable of changing the intake timing. Specifically, the IVC pump OP1 operated by the engine E is operated as a hydraulic pressure source, and the valve timing on the intake side can be changed in the range from the most retarded position to the most advanced position. Further, it has a lock mechanism that can fix the valve timing to a predetermined timing even when the IVC pump OP1 is not operated. The lock mechanism includes: a first lock mechanism that can be fixed at the most retarded angle position; and a second lock mechanism that can be fixed at an intermediate position located slightly on the advance side of the intermediate position between the most retarded angle position and the most advanced angle position. It is configured. Hereinafter, the valve timing fixed by the first lock mechanism is described as a decompression valve tie (most retarded position), and the valve timing fixed by the second lock mechanism is described as an intermediate lock valve tie. Further, although there is no particular locking mechanism, the valve timing set when the engine E is idling is described as idle time valve timing.

The first clutch CL1 is a clutch interposed between the engine E and the motor generator MG, and slips by the control hydraulic pressure generated by the first clutch hydraulic unit based on the control command from the first clutch controller 5. The fastening / opening is controlled including the fastening.

Motor generator MG is a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator, and applies a three-phase alternating current generated by inverter 2a based on a control command from motor controller 2. Is controlled. The motor generator MG can operate as an electric motor that is driven to rotate by receiving power supplied from the battery 20 (hereinafter, this state is referred to as “powering”), or when the rotor is rotated by an external force. Can function as a generator that generates electromotive force at both ends of the stator coil to charge the battery 20 (hereinafter, this operation state is referred to as “regeneration”).

The second clutch CL2 is a clutch interposed between the motor generator MG and the left and right front wheels FL, FR. Based on the control command from the CL2 controller 6, the second clutch CL2 is controlled by the control hydraulic pressure generated by the second clutch hydraulic unit. The fastening and opening are controlled including slip fastening.

The belt-type continuously variable transmission CVT consists of a primary pulley, a secondary pulley, and a belt that is stretched around these pulleys. It is a step transmission, and the gear ratio is controlled based on a control command from the CVT controller 7. Further, the belt type continuously variable transmission CVT has a transmission pump OP2 driven by a motor generator MG, and even when the engine is stopped, the hydraulic pressure is secured by the operation of the motor generator MG, and the gear ratio or The engagement state of the two clutch CL2 is configured to be controllable.

The output shaft of the belt type continuously variable transmission CVT is connected to the left and right front wheels FL and FR via a propeller shaft PS, a differential gear DF, a left drive shaft DSL, and a right drive shaft DSR as vehicle drive shafts. The first clutch CL1 and the second clutch CL2 are, for example, wet multi-plate clutches that can continuously control the oil flow rate and hydraulic pressure with a proportional solenoid.

This hybrid drive system has at least two travel modes according to the engaged / released state of the first clutch CL1. The first travel mode is an electric vehicle travel mode (hereinafter abbreviated as “EV travel mode”) as a motor use travel mode that travels using only the power of the motor generator MG as a power source with the first clutch CL1 opened. It is. The second travel mode is an engine use travel mode (hereinafter abbreviated as “HEV travel mode”) in which the first clutch CL1 is engaged and the engine E is included in the power source. When transitioning from the EV travel mode to the HEV travel mode, the first clutch CL1 is engaged and the engine is started using the torque of the motor generator MG.

The “HEV travel mode” has three travel modes of “engine travel mode”, “motor assist travel mode”, and “travel power generation mode”. In the “engine running mode”, the drive wheels are moved using only the engine E as a power source. In the “motor assist travel mode”, the drive wheels are moved by using the engine E and the motor generator MG as power sources. The “running power generation mode” causes the motor generator MG to function as a generator at the same time as the drive wheels RR and RL are moved using the engine E as a power source. During constant speed operation or acceleration operation, motor generator MG is operated as a generator using the power of engine E. Further, during deceleration operation, braking energy is regenerated to generate electric power by the motor generator MG and used for charging the battery 20. Further, as a further mode, there is a power generation mode in which the motor generator MG is operated as a generator using the power of the engine E when the vehicle is stopped.

The integrated controller 10 manages the energy consumption of the entire vehicle and has a function for running the vehicle with maximum efficiency. Various sensor information and range position information detected by the range position sensor 8 provided on the shift lever. , The on / off information of the ignition switch 9 and the information obtained via the CAN communication line 11 are input. The integrated controller 10 also controls the operation of the engine E according to the control command to the engine controller 1, the operation control of the motor generator MG based on the control command to the motor controller 2, and the first control command to the first clutch controller 5. Engagement / release control of the clutch CL1, engagement / release control of the second clutch CL2 by a control command to the second clutch controller 6, and shift control by a control command to the CVT controller 7 are performed.

(Valve timing control processing)
Next, a description will be given of the valve timing control process for controlling the vehicle from being in a stopped position to a position other than the intermediate lock valve tie. First, the necessity of the valve timing control process will be described. For example, when the engine E is warmed up, the valve timing changing mechanism IVC is changed from the HEV running mode to the EV running mode, and when the engine E is stopped, the valve timing changing mechanism IVC controls to the decompression tie. This is because when the engine is restarted, where the friction is considered to be sufficiently reduced due to the end of warm-up, the engine speed is set so that the engine speed can quickly get out of the low speed range where the engine speed and the vehicle body side resonate (eg, 200 rpm to 400 rpm). This is to raise the speed quickly. That is, by using a decompression tie, the intake valve closing timing when moving toward the piston top dead center is delayed, and the pumping load in the engine cylinder is reduced.

On the other hand, when the system is stopped such as when the ignition is turned off, it is unknown when the timing when the ignition is turned on again. In such a case, if the engine E is stopped with the decompression valve tie still maintained, if the engine friction is large as in the case of the cold engine start next time, sufficient torque cannot be obtained and proper engine start may not be achieved. is there. Therefore, when there is a possibility of cold start, the intermediate lock valve tie secures the pumping load in the engine cylinder without delaying the intake valve closing timing, thereby securing the torque at engine start. To do.

In the hybrid vehicle of the first embodiment, when the ignition is turned off in the state of the decompression valve tie or in the state of the idle valve tie that is retarded from the intermediate lock valve tie, if the engine E is stopped as it is, the subsequent ignition on Appropriate valve timing may not be obtained when the engine is restarted. Therefore, when the engine is stopped due to the ignition off, it is preferable to stop the operation of the engine E after shifting to the intermediate lock valve timing.

However, in the case of a hybrid vehicle, the decompression valve tie and the idle valve tie are extremely retarded because of the demand to increase the fuel efficiency to the limit and the fact that the motor generator MG can recover even if the engine start by the normal starter motor fails. There is a strong tendency to be set on the side. For this reason, when moving to the position of the intermediate lock valve tie, the amount of control (the magnitude of the angle to move from the retarded position to the advanced position) is larger than that of the engine vehicle, which may take time.

At this time, since the hybrid vehicle of the first embodiment employs an inexpensive valve timing changing mechanism IVC that uses the IVC pump OP1 driven by the engine E as a hydraulic pressure source, an intermediate lock is provided if the engine E is not operating. It cannot be moved to Valtai. That is, it may take time from the ignition off to the stop of the engine E, which may give the driver a sense of discomfort. In addition, if the ignition is turned off while the engine is running in the EV running mode, the system may stop with the decompression tie.

Therefore, in the first embodiment, even when the ignition is turned off in the hybrid vehicle, the above problem is solved by controlling the valve timing to an appropriate position without performing unnecessary fuel injection.

FIG. 2 is a flowchart showing a valve timing control process executed in the hybrid vehicle control apparatus of the first embodiment.
In step S1, it is determined whether or not there is a request for ignition off. If it is determined that there is a request, the process proceeds to step S2, and otherwise, the control flow ends.
In step S2, it is determined whether or not the valve timing changing mechanism IVC is positioned at the intermediate lock valve tie. When the valve timing change mechanism IVC is positioned at the intermediate lock valve tie, the process proceeds to step S15 and the system off process is executed. Proceed to S3.

In step S3, it is determined whether or not the shift range is located in the P range or the N range. If the shift range is located in the P or N range, the process proceeds to step S5. Otherwise, the process proceeds to step S4. move on.
In step S4, it is determined whether or not the vehicle is in the HEV traveling mode. If it is determined that the vehicle is in the HEV traveling mode, that is, the engine is operating, the process proceeds to step S7. Otherwise, the control flow is terminated. In other words, if the engine is in an operating state, the process proceeds to step S7 and subsequent steps in this control flow regardless of the shift range position.

In step S5, it is determined whether or not the engine is stopped. If the engine is stopped, the process proceeds to step S6. If the engine is operated, the process proceeds to step S7.
In step S6, the first clutch CL1 is engaged by slip control or the like, and the engine speed is increased by the motor generator MG. This is to operate the IVC pump OP1.

In step S7, an ignition-off delay request is output. This ignition-off delay request is a request for shutting down the system after performing a process to be described later by delaying the system shut-off by a predetermined time if it is a normal ignition-off process.
In step S8, the timer starts counting.
In step S9, the advance processing of the valve timing changing mechanism IVC is started. Specifically, control is performed from the current position (decompression valve tie or idle valve tie) toward the intermediate lock valve tie. When locked by the first lock mechanism, first secure the hydraulic pressure, unlock the first lock mechanism, perform advance processing, and operate the second lock mechanism to complete the movement to the intermediate lock valve tie Execute the process.

In step S10, it is determined whether or not the timer count value has reached a predetermined time T1, which is set in advance. If it is determined that the timer count value has not been reached, the process proceeds to step S14. Otherwise, the process proceeds to step S11.
In step S11, the fuel injection of the engine is stopped.

In step S12, rotation maintenance control by motor generator MG is performed, and the engine rotation speed is maintained by rotation speed control of motor generator MG. As a result, the operation of the IVC pump OP1 is secured, and the advance processing of the valve timing changing mechanism IVC is continued.
In step S13, it is determined whether or not the timer count value has reached a predetermined time T2 longer than T1, and when it is determined that the timer count value has not reached, the process proceeds to step S14. Execute the system stop process.

In step S14, it is determined whether or not the second lock mechanism has been locked by moving to the intermediate lock valve tie. If it is determined that the lock has been completed, the process proceeds to step S15. If it is determined that the lock has not been completed, Returning to step S10, the advance angle processing is continued. Whether or not the lock has been completed is determined by providing the second lock mechanism with a hydraulic switch, a contact switch, or the like, thereby determining whether the lock has been completed, or outputting an operation request signal for the second lock mechanism. The determination may be made based on whether or not a predetermined time has passed.
In step S15, a system stop process is executed.

FIG. 3 is a time chart showing valve timing control processing executed when the engine is operated in the hybrid vehicle control apparatus of the first embodiment. This time chart shows a case where the ignition switch is turned off in the engine operating state and in the P range position. The state before the valve timing control process is a vehicle stop state in which the engine E is operating, the first clutch CL1 is engaged, and the second clutch CL2 is released. In addition, it is assumed that the motor generator MG is controlled so as to maintain the idle rotational speed.

At time t1, when the driver pushes the ignition switch 9, a Push signal is output, and the process of switching the ignition switch 9 from on to off is started. At this time, since the valve timing changing mechanism IVC is located in the idle valve timing, an ignition-off delay request is output and delayed by T1 (for example, 1 second). During this time, engine fuel injection is continued, prompting rapid advance processing.

At time t2, when a predetermined time T1 has elapsed, fuel injection is stopped. This is because it is uncomfortable to continue the engine fuel injection for a long time after the driver turns off the ignition switch 9, and the fuel efficiency may deteriorate. Then, by controlling the rotational speed of the motor generator MG, the engine rotational speed is maintained at the idle rotational speed, thereby ensuring the pump discharge amount of the IVC pump OP1, thereby ensuring the continuation of the advance processing. It should be noted that when the engine E rotates idly with fuel injection stopped, no vibration or the like is generated, so that the driver does not feel uncomfortable.

At time t3, if it is determined that the movement to the intermediate lock valve tie has been completed with certainty before the predetermined time T2 has elapsed, the system is stopped. When the system is stopped, the first clutch CL1 is released, and the engine E and the motor generator MG are reduced in speed according to their respective inertia and friction and stopped. In addition, when it moves to the intermediate lock valve tie before the predetermined time T2 elapses and it is not determined that the lock is completed, the system is stopped when the predetermined time T2 elapses. Thereby, the situation where a system does not stop can be avoided.

FIG. 4 is a time chart showing a valve timing control process executed when the engine is stopped in the hybrid vehicle control apparatus of the first embodiment. This time chart shows a case where the engine is stopped and the ignition switch is turned off in the P range position. The state before the valve timing control process is the vehicle stop state in which the engine E is stopped and the first clutch CL1 and the second clutch CL2 are released, and the transmission pump OP2 is driven by the idle rotation of the motor generator MG. Is in a state where a predetermined hydraulic pressure is supplied to the belt type continuously variable transmission CVT.

When the driver depresses the ignition switch 9 at time t1, a Push signal is output, and a process of switching the ignition switch 9 from on to off is started. At this time, since the engine is stopped, the valve timing changing mechanism IVC is positioned in the decompression tie, and an ignition-off delay request is output and delayed by T1. However, fuel injection is not resumed because the engine is stopped.
Further, the first clutch CL1 is engaged by slip control or the like, the engine speed is increased by the motor generator MG, and thereby the advancement process is executed by securing the pump discharge amount of the IVC pump OP1.

At time t2, although the predetermined time T1 has elapsed, since fuel injection is not originally performed, the rotational speed control by the motor generator MG is continuously performed, and the advance angle control is continued. At time t3, it is determined that the movement to the intermediate lock valve tie has been completed, and the system is stopped. When the system is stopped, the first clutch CL1 is released, and the engine E and the motor generator MG are reduced in speed according to their respective inertia and friction and stopped. In addition, when it moves to the intermediate lock valve tie before the predetermined time T2 elapses and it is not determined that the lock is completed, the system is stopped when the predetermined time T2 elapses. Thereby, the situation where a system does not stop can be avoided.

As described above, in the hybrid vehicle of the first embodiment, the following effects can be obtained.
(1) The hydraulic oil is supplied by the IVC pump OP1 (pump) driven by the engine E, and the intake valve can be changed to the advance side or the retard side within a predetermined range. The valve timing changing mechanism IVC (valve timing changing means) having a second locking mechanism that can be locked at the advanced angle position, the motor generator MG (motor) arranged in series with the engine E, and the ignition switch 9 being turned off, the vehicle When the integrated controller 10 (system stop means) for stopping the system and the ignition switch 9 are turned off and the valve timing changing mechanism IVC is other than the intermediate lock valve tie (predetermined advance position), the vehicle system is stopped. The motor generator MG maintains the rotation of the engine E with the delay and the fuel injection of the engine E stopped. Holding the hydraulic fluid, changing the valve timing changing mechanism IVC to the intermediate lock valve tie and locking the vehicle system, and then stopping the vehicle system.
Therefore, the system can be stopped after moving to the intermediate lock valve timing position regardless of the advance angle or retard angle position, so that the engine can be reliably restarted when the ignition is turned on next time. Even if it takes time to stop the system, the fuel injection is stopped and the engine speed is maintained by the motor generator MG. Therefore, the valve timing changing mechanism IVC can be advanced without causing the driver to feel uncomfortable.

(2) When the ignition switch 9 is turned off in the engine operating state and the valve timing changing mechanism IVC is other than the intermediate lock valve tie, the stop of the vehicle system is delayed and the fuel injection of the engine E is continued for a predetermined time T1. In this state, the motor generator MG maintains the rotation of the engine E to supply hydraulic oil, the valve timing changing mechanism IVC is changed to the intermediate lock valve tie, and the valve timing changing mechanism IVC is changed to the second lock mechanism within a predetermined time T1. If locked, the vehicle system is stopped without going through steps S11 and S12 (without performing system stop delay means), and if the valve timing changing mechanism IVC cannot be locked within a predetermined time T1, steps S11 and S12 (the system The system shifts to (stop delay means) (second system stop delay means).
That is, by continuing fuel injection in a range where the driver does not feel uncomfortable, the valve timing changing mechanism IVC can be advanced while suppressing power consumption.

(3) When the engine E is not operating, the ignition switch 9 is turned off, and the valve timing changing mechanism IVC is other than the intermediate lock valve tie, the motor generator MG increases the rotation of the engine E, and the step S11 and S12 are executed.
Therefore, even when the ignition switch is off while the engine is stopped, the valve timing changing mechanism IVC can be moved to the intermediate lock valve tie, and the engine startability can be ensured when the ignition switch is turned on the next time.

Claims

Hydraulic oil is supplied by a pump driven by the engine, and the intake valve can be changed to the advance side or retard side within a predetermined range, and can be locked at a predetermined advance position regardless of the presence or absence of the hydraulic oil. Valve timing changing means;
A motor arranged in series with the engine;
System stopping means for stopping the vehicle system by turning off the ignition switch;
When the ignition switch is turned off and the valve timing changing means is other than a predetermined advance position, the stop of the vehicle system by the system stop means is delayed, and the fuel injection of the engine is stopped. A system stop delay means for stopping the vehicle system after maintaining the rotation of the engine by a motor, supplying the hydraulic oil, changing the valve timing changing means to the predetermined advance position and locking;
A control apparatus for a hybrid vehicle, comprising:
In the hybrid vehicle control device according to claim 1,
When the ignition switch is turned off in the engine operating state and the valve timing changing means is other than a predetermined advance position, the stop of the vehicle system by the system stop means is delayed, and fuel injection of the engine is performed for a predetermined time. In a continued state, the engine is rotated by the motor and the hydraulic oil is supplied, the valve timing changing means is changed to the predetermined advance position, and the valve timing changing means is changed within the predetermined time. A second system stop delay means that stops the vehicle system without performing the system stop delay means when locked, and shifts to the system stop delay means when the valve timing changing means cannot be locked within the predetermined time. A control device for a hybrid vehicle, comprising:
In the hybrid vehicle control device according to claim 1,
When the engine is inactive, the ignition switch is turned off, and the valve timing changing means is in a position other than a predetermined advance position, the rotation of the engine is increased by the motor before the system stop delay A control apparatus for a hybrid vehicle, characterized in that the means is executed.