Engine startup control device and control method

Details Engine startup control device and control method Engine startup control device and control method

1999-10-05

2001-06-26

Cuchlinski, Jr., William A. (Department: 3661)

Data processing: vehicles, navigation, and relative location

Vehicle control, guidance, operation, or indication

Electric vehicle

C123S179100, C701S113000

Reexamination Certificate

active

06253127

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to output control of a motor for starting a vehicle engine.
BACKGROUND OF THE INVENTION
A parallel hybrid vehicle comprising a motor and an engine as sources of drive force, which runs under the drive force of either or both of the motor and engine, is disclosed on pp. 39-52 of “Automotive Engineering” Vol.46 No.7 June, 1997 published by the Tetsudo Nihon Sha.
This vehicle runs only under the drive force of the motor when the vehicle load is small, and the engine is operated to increase the drive force when the vehicle load exceeds a predetermined level.
SUMMARY OF THE INVENTION
In such a parallel hybrid vehicle, when a shift is performed from running on the motor alone to running on the engine together with the motor, the engine is started by a starter motor.
This starter motor operates also as a power generator after the engine starts its operation.
When the starter motor cranks up the engine, it is preferable to supply a large amount of power to the starter motor so as to ensure the start of the engine. However, this may make the battery go into an over discharge, which is a discharge beyond the power limit determined by the state of charge of the battery. Such an over discharge causes deterioration of the battery. In particular, when the battery temperature is low, the power which can be supplied by the battery is small, and an over discharge tends to occur easily. Moreover, at low temperature, the period during which the battery can supply power is also short.
On the other hand, after the cranking of the engine, the rotation speed of the engine must be quickly controlled to a target rotation speed so as to match the running state of the vehicle or the required power generation amount of the vehicle.
A delay in this control may cause the increase of battery power consumption as well as adversely affect the drivability of the vehicle.
It is therefore an object of this invention to properly control the output of the motor during startup of the engine.
In order to achieve the above object, this invention provides an engine startup control device for use with a hybrid vehicle. The vehicle comprises an engine, a first motor for starting the engine, a generator for driving the engine, a drive wheel connected to the engine via a clutch, a second motor for driving the drive wheel and a battery which can be connected to the first motor, the second motor and the generator. The control device comprises a sensor which detects a rotation speed of the engine, a sensor which detects a charge amount of the battery, a power controller which varies a current supplied to the first motor according to a signal, and a microprocessor programmed to calculate a target output torque of the first motor according to the charge amount of the battery, set the signal so that an output torque of the first motor coincides with a predetermined target output torque when the rotation speed of the engine is less than a predetermined target rotation speed, and set the signal so that the rotation speed of the engine is maintained at the target rotation speed after the rotation speed has reached the target rotation speed.
This invention also provides an engine startup control method for a hybrid vehicle. The vehicle comprises an engine, a first motor for starting the engine, a generator for driving the engine, a drive wheel connected to the engine via a clutch, a second motor for driving the drive wheel, a battery which can be connected to the first motor, the second motor and the generator, and a power controller which varies a current supplied to the first motor according to a signal. The control method comprises detecting a rotation speed of the engine, detecting a charge amount of the battery, calculating a target output torque of the first motor according to the charge amount of the battery, setting the signal so that an output torque of the first motor coincides with a predetermined target output torque when the rotation speed of the engine is less than a predetermined target rotation speed, and setting the signal so that the rotation speed of the engine is maintained at the target rotation speed after the rotation speed has reached the target rotation speed.


REFERENCES:
patent: 4009695 (1977-03-01), Ule
patent: 4192279 (1980-03-01), Maisch et al.
Tetsudo Nihon Sha, “Automotive Engineering”, vol. 46, No. 7, pp. 39-52, (Jun., 1997).

Affiliated with

Also associated with

Rating

Engine startup control device and control method does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Engine startup control device and control method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Engine startup control device and control method will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2523487