Interrelated power delivery controls – including engine control – Plural engines – Electric engine
Reexamination Certificate
2001-01-12
2003-04-29
Lavinder, Jack (Department: 3683)
Interrelated power delivery controls, including engine control
Plural engines
Electric engine
C477S906000
Reexamination Certificate
active
06554736
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hybrid vehicle constructed so that running drive can be effected by transmitting engine output through a gear-change mechanism to the vehicle and running drive is also possible by means of a drive motor that is arranged in parallel with the engine, so that, in prescribed operating conditions, the engine may be temporarily stopped and running drive may be performed by driving the vehicle by means of the drive motor.
2. Description of the Related Art
Efforts are being made to put into practice hybrid vehicles wherein running can be performed using engine drive and electric motor drive in combination, with the object of improving engine fuel consumption, etc. Such a hybrid vehicle is disclosed for example in Laid-open Japanese Patent Application Number H.11-132321. This vehicle comprises an engine, a first motor generator connected to the engine crankshaft, a belt type infinitely variable gear-change mechanism connected to the engine output shaft through a torque converter, and a second motor generator connected to a power transmission system on the output side of this infinitely variable gear-change mechanism. This vehicle is arranged such that ordinary running is performed by converting the gear ratio of the engine driving force in the infinitely variable gear-change mechanism before transmitting it to the vehicle wheels; when the vehicle is temporarily stopped, the engine is also temporarily stopped; and when subsequently the vehicle is made to move off, the vehicle wheels are driven by a second motor generator. It should be noted that, when the vehicle is thus made to move off again, the engine is restarted by the first motor generator, and after the vehicle has moved off a changeover is effected to running using engine drive.
If the engine is thus stopped when the vehicle is temporarily stopped, hydraulic pump drive by the engine is also stopped, causing the hydraulic pressure of the infinitely variable gearchange mechanism to be lost. Accordingly, a second hydraulic pump is provided that is driven by an electric motor and when the engine is stopped a prescribed hydraulic pressure is generated by driving the second hydraulic pump by means of this electric motor so as to prepare for the next move-off in a condition with the gear ratio set to the maximum (LOW) to enable motive force transmission, by supplying this prescribed hydraulic pressure to the output pulley cylinder chamber of the infinitely variable gear-change mechanism. In this way, in a hybrid vehicle as described above, an improvement is sought to be achieved with respect to fuel costs by stopping the engine when the vehicle is temporarily stopped, and an improvement with respect to fuel costs is sought to be achieved by driving the vehicle wheels using the second motor generator when moving off.
Consideration has also been given, with the object of further improving the fuel consumption, to stopping the engine and performing running using the electric motor drive also when the vehicle is running at comparatively high speed. If, in this case, the conventional hybrid vehicle control described above is employed without modification, the following problems arise.
Conventionally, when the engine was stopped in a condition where the vehicle was temporarily stopped, it was arranged for the clutch, which is provided in the power transmission system, to be prepared for the next move-off by being in an engaged condition, by hydraulic fluid pressure supplied from the second hydraulic fluid pump during the engine stoppage. However, if the clutch is put in engaged condition when the engine is stopped during running, the problem arises that the gear-change mechanism and the torque converter are rotated by the driving force from the vehicle wheels, generating entrainment torque, necessitating additional driving torque from the electric motor, thereby lowering drive efficiency. This is the reason why the clutch is disengaged when running is performed by means of the electric motor drive with the engine stopped.
However, when the arrangement is made such that the clutch is disengaged while running is performed using the electric motor drive, that is, the clutch is engaged and disengaged during the running by the engine drive and during the running by the electric motor drive, respectively, problems will arise if the controllability of engaging and disengaging the clutch is lowered that the switching over can not be done at a required timing, or a shock is created during the switching over operation. For example, in a case when the clutch engagement/disengagement control is performed by the use of hydraulic pressure, such problems will arise if a control valve for control of hydraulic engagement/disengagement of the clutch deteriorates or causes malfunction.
Further, there will also be a problem that the clutch is left in its disengaged state and becomes unable to be engaged due to the malfunction of the control valve, and in such a case the running performance of the vehicle is deteriorated. For example, in a case of a clutch that is engaged/disengaged by hydraulic pressure, such problem will arise if the spool of a control valve that control supply of working hydraulic pressure to the clutch is fixed at the position to block the supply of working hydraulic pressure due to its sticking. If the clutch is left in the disengaged state in this way, the output of the activated engine can not be transferred to the vehicle wheels, whereby the vehicle will be forced to travel only with the electric motor drive, without the engine drive and can not obtain sufficient driving force.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a hybrid vehicle control device of a construction wherein means for engagement/disengagement such as a clutch are engaged/disengaged during running using an electrically driven motor drive and running using engine drive, such that engagement of the means for engagement/disengagement can be effected even when abnormality (electrical malfunction, i.e., failure of the gear-change mechanism and/or malfunction of the control valve etc) of the means for controlling the engagement/disengagement action of the means for engagement/disengagement occurs, without being affected by such abnormality.
According to the present invention, there is provided a hybrid vehicle comprising: an engine capable of temporary stoppage control in a prescribed operating condition, a gear-change mechanism (for example infinitely variable gear-change mechanism
20
) connected to the output shaft of this engine and whereby its output rotation is changed in gear ratio; a driving force transmission system (for example, idler shaft
31
, final drive gear
32
, final driven gear
33
, differential mechanism
34
, and axle shafts
35
) that transmits the output of this gear-change mechanism to the driven wheels; an electrically driven motor (for example, second motor generator
50
) capable of driving said driven wheels and connected to this driving force transmission system, and means for engagement/disengagement (for example forwards/reverse changeover mechanism
10
) arranged in a path from the output shaft of said engine to said driving force transmission system and that perform engagement/disengagement control, arranged such that running drive can be performed by transmission of the output of the engine to the driven wheels through the gear-change mechanism and power transmission system by engagement of the means for engagement/disengagement and running drive can be performed by transmission of driving force of the electrically driven motor to the driven wheels in a condition with the means for engagement/disengagement released. Furthermore, this control device comprises auxiliary means for engagement control that, when abnormality of the gearchange mechanism is detected, are capable of engaging the means for engagement/disengagement without being affected by this abnormality, and is such that, when, in a condition with the means for
Morishita Naohisa
Takano Mikihiro
Honda Giken Kogyo Kabushiki Kaisha
Lavinder Jack
Williams Thomas J.
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