Hybrid vehicle

Details Hybrid vehicle Hybrid vehicle

2001-01-23

2002-12-03

Estremsky, Sherry (Department: 3681)

Interrelated power delivery controls, including engine control

Plural engines

Electric engine

C477S005000, C477S006000, C477S008000, C180S065230, C180S065310, C180S065700

Reexamination Certificate

active

06488608

ABSTRACT:

CROSS REFERENCE TO RELATED APPLICATIONS
The present invention claims priority from Japanese Patent Applications No. 2000-014715 filed Jan. 24, 2000 and No. 2000-017324 filed Jan. 26, 2000, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hybrid car using both an internal combustion engine and a motor-generator and, particularly, the present invention relates to a novel hybrid car capable of realizing a series-parallel hybrid system, which utilizes a single electric rotary machine and has small fuel consumption.
2. Description of Related Art
The hybrid car having an internal combustion engine and a motor-generator can be roughly classified to a series system and a parallel system on the basis of driving system.
In the hybrid car of the series system, an internal combustion engine is mechanically connected such that the internal combustion engine drives a generator and an axle of the car is mechanically connected such that the axle is driven by a motor. That is, the car is driven by the motor supplied with electric energy generated by the generator driven by the internal combustion engine. In the series system, it is usual that the electric energy supplied from the generator is used to recharge a storage battery and the motor is driven by the storage battery. When braking energy is regenerated in the series system, the motor ganged with the axle is switched to a generator mode and rotary energy supplied from the axle is converted into electric energy with which the storage battery is recharged. Fuel (gasoline, etc.) used in the internal combustion engine is externally supplied and the storage battery may be recharged by externally supplying recharging current thereto.
The parallel system is constructed by mechanically connecting a motor-generator directly to an internal combustion engine driving an axle. By using the motor-generator as a motor and supplying electric energy from a storage battery to the motor, it is possible to drive the axle by both the internal combustion engine and the motor. In braking the car, it is possible to perform a regenerative braking for recharging the storage battery by operating the motor-generator as a generator. Further, it is possible to recharge the storage battery with electric energy generated by the motor-generator during a parking time of the car by shifting a change gear to neutral or decoupling a clutch to switch the operating mode of the motor-generator to the generator mode, driving the motor-generator operating as the generator by the internal combustion engine and supplying an electric output of the motor-generator to the storage battery. Alternatively, it is possible to recharge the storage battery by operating the motor-generator as the generator during a running state of the car with the change gear and the clutch being connected and driving both the axle and the generator by the internal combustion engine. Fuel for the internal combustion engine is supplied externally and the storage battery can be recharged by supplying recharging current externally. This system has been utilized in HIMR's manufactured and sold by the assignee of this application.
The series system allows a car to be operated by selectively setting the rotation speed of an internal combustion engine regardless of the running state of the car. That is, in the case where the recharging of the storage battery is performed during either the running state or the parking state of the car, it is possible, according to the load current and the recharging state of the storage battery, to control the operation of the internal combustion engine such that rotation speed thereof becomes in a range within which fuel efficiency is high or in a range within which the amount of exhaust gas becomes minimum.
On the contrary, since the parallel system can operate both the internal combustion engine and the motor, it is possible to increase the maximum torque generated in running on an uphill road or in starting with acceleration. However, since the rotation speed of internal combustion engine is generally changed correspondingly to the running condition of the car, it is impossible to continuously drive the car at rotation speed or speeds in the range in which fuel efficiency is high. Therefore, the parallel system is considered as to be suitable for a large size vehicle such as a bus or truck which requires a large instantaneous maximum torque.
A system which utilizes the merits of both the series system and the parallel system is disclosed in JP H11-75302 A filed by the present assignee. A construction of the system is shown in FIG.
1
. In
FIG. 1
, a vehicle of the system uses first motor-generator
2
a
and second motor-generator
2
b
. First motor-generator
2
a
is directly connected to internal combustion engine
1
and first clutch
3
a
is provided between first motor-generator
2
a
and change gear
4
. second motor-generator
2
b
is connected to the change gear side of first clutch
3
a
through second clutch
3
b
. Second motor-generator
2
b
is connected to a main shaft through gear train
4
a
provided on an input side of change gear
4
.
In this construction, since, when first clutch
3
a
is separated, rotation of internal combustion engine
1
is not transmitted to change gear
4
, internal combustion engine
1
drives first motor-generator
2
a
as a generator to recharge a storage battery and the vehicle is driven with energy supplied from second motor-generator
2
b
and the storage battery by operating second motor-generator
2
b
as a motor and connecting second clutch
3
b
. In this operation mode, the system becomes the series system mentioned above. Since, when first clutch
3
a
is connected in this operation mode, the vehicle can be driven directly by internal combustion engine
1
and first motor-generator
2
a
can be utilized as the motor simultaneously, this system becomes the parallel system mentioned above. When this system is operated as the series system, it is possible to selectively set an engine rotation in an efficient rotation speed range to thereby improve the fuel consumption and, when this system is operated as the parallel system, it is possible to increase the instantaneous torque. In the system shown in
FIG. 1
, when the regenerative braking is performed, it is possible to effectively regenerate braking energy from second motor-generator
2
b
by separating first clutch
3
a
, without influence of friction of internal combustion engine
1
. However, it is necessary, in this system, to control the two clutches, as mentioned.
German Patent Publication No. 2943554 (Volkswagen) discloses a technique, which belongs to the above mentioned parallel system and in which an internal combustion engine, a motor-generator, a first clutch and a change gear are connected in the sequence and a second clutch is provided between the internal combustion engine and the motor-generator. That is, the disclosed construction allows a vehicle to be operated as either the parallel system or a modified series system with using a single electric rotary machine. In the disclosed system, however, it is necessary to provide the second clutch, which is large in size, and to operate the large clutch correspondingly to the operation mode. Therefore, a special clutch mechanism using an oil pressure system and an electronic device for controlling the clutch mechanism are indispensable.
Demand for hybrid car, particularly, hybrid cars having high fuel efficiency, is very brisk in the recent market. Further, there is a severe demand for hybrid car having high exhaust gas purification performance looking far ahead into the future. Under the circumstances, it becomes necessary to study the possibility of employment of the above mentioned series system in a large commercial vehicle such as a bus and/or truck. In the series system mentioned above, a vehicle can be driven by electric energy obtained from a generator driven an internal combustion engine, in which case, the

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