Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Electric vehicle
Reexamination Certificate
1999-08-12
2001-03-20
Camby, Richard M. (Department: 3618)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Electric vehicle
C180S165000, C180S193000, C180S193000
Reexamination Certificate
active
06205379
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a controller for a hybrid front-and-rear-drive automotive vehicle wherein an engine and an electric motor are provided as two drive power sources for operating one and the other of front and rear wheel drive systems, respectively.
2. Discussion of the Related Art
There is known an automotive vehicle of a type wherein an internal combustion engine is used to drive one of a front wheel drive system and a rear wheel drive system while an electric motor is used to drive the other of the front and rear wheel drive systems. In this type of automotive vehicle, all of the four wheels can be driven by concurrent operations of the engine and the electric motor. For instance, the electric motor is activated to drive the wheels of one of the front and rear wheel drive systems while the wheels of the other drive system is operated by the engine. In this respect, the vehicle of the type in question may be called a hybrid 4-wheel-drive vehicle. For improved overall driving performance of this hybrid 4-wheel-drive vehicle while maintaining high degrees of fuel economy and other running characteristics of the vehicle, the electric motor is activated to assist the engine, namely, to provide an engine-assisting motor drive torque only where the vehicle is placed in a predetermined running condition requiring acceleration of the vehicle.
In the field of such a hybrid front-and-rear-drive vehicle, it has been proposed to provide an electric generator operable by the engine for generating an electric energy used for operating the electric motor, in an attempt to eliminate a high-voltage battery for operating the electric motor, and reducing the size of the electric motor. An example of such a hybrid front-and-rear-drive vehicle is disclosed in JP-A-8-126117.
In the hybrid front-and-rear-drive vehicle wherein the electric motor is operated by an electric energy supplied thereto directly from the electric generator driven by the engine, as described above, however, an operation of the electric motor is more or less delayed since it takes a time for the electric energy to rise to a level sufficient for starting the electric motor. Accordingly, an increase of the engine-assisting torque generated by the electric motor is delayed. Where the vehicle is started on an ascending road surface having a relatively high gradient, by concurrent operations of the engine and the electric motor, the delayed increase of the engine-assisting motor torque will unfavorable lead to initial slipping of the wheels driven by the engine on the ascending road surface.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a controller for a hybrid front-and-rear-drive automotive vehicle wherein one and the other of the front and rear wheel drive systems are driven by an engine and an electric motor, respectively, which controller is adapted to effectively prevent a delay in an increase in the engine-assisting torque generated by the electric motor that is operated with an electric energy generated by an electric generator driven by the engine.
The above object may be achieved according to the principle of this invention, which provides a controller for controlling a hybrid front-and-rear-drive automotive vehicle including a front wheel and a rear wheel, an engine, an electric generator operated by the engine, and an electric motor operable with an electric energy generated by the electric generator, and wherein one and the other of the front and rear wheels is driven by the engine and the electric motor, respectively, the controller comprising: an electric energy storage device; and cooperative energy supply means for supplying an electric current from the electric energy storage device to the electric motor, concurrently with a supply of an electric energy from the electric generator to the electric motor, to operate the electric motor for driving the other of the front and rear wheels.
In the controller constructed according to the present invention as described above, the electric energy storage device is provided as a second power source for supplying an electric energy to the electric motor, in addition to the electric generator which is operated by the engine and provided as a first power source for operating the electric motor. When the electric motor is operated to drive the rear wheel, for example, to provide an engine assisting drive force for assisting the engine operating to drive the front wheel to start the vehicle, the cooperative energy supply means is operated to supply the electric energy from the electric energy storage device to the electric motor concurrently with the supply of the electric energy from the electric generator to the electric motor. This arrangement permits a sufficiently high rate of rise or increase of the engine assisting drive torque of the electric motor, even with some delay in the rise or increase of the amount of electric energy supplied to the electric motor from the electric generator operated by the engine. Accordingly, the vehicle can be smoothly started without significant slipping of the front wheel serving as the primary drive wheel, and can be run with high drivability even on an uphill road surface.
In one preferred form of the controller of the present invention, the electric energy storage device includes a capacitor which stores the electric energy by polarization of a dielectric material and which has an energy storage capacity sufficient to compensate for an initial shortage of the electric energy to operate the electric motor, which initial shortage would arise from a delayed increase of an amount of the electric energy supplied from the electric generator to the electric motor, if the electric motor were operated with only the electric energy supplied from the electric generator.
In the above preferred form of the invention, the capacitor of the type indicated above permits a sufficiently high rate of rise or increase of the electric energy to be supplied to the electric motor. The provision of the capacitor assures a further increase in the rate of rise of the engine assisting drive torque of the electric motor.
In another preferred form of the invention, the controller further comprises: a gradient detector for detecting a gradient of a road surface on which the vehicle lies; and electric power source control means for controlling, depending upon the gradient detected by the gradient detector, a ratio of the amount of electric energy to be supplied from the electric energy storage device to the electric motor, with respect to the amount of electric energy supplied from the electric generator to the electric motor. For instance, the electric power source control means may be adapted to reduce the above-indicated ratio of the amount of electric energy to be supplied from the electric energy storage device to the electric motor is reduced as the gradient is reduced. Alternatively, the electric power source control means may consist of electric power source switching means for zeroing the amount of electric energy to be supplied from the electric energy storage device to the electric motor when the gradient detected by the gradient detector is lower than a predetermined threshold. Thus, the electric power source control means is effective to reduce the amount of consumption of the electric energy stored in the electric energy storage device.
In a further preferred form of the invention, the controller further comprises charging means operated immediately after termination of an operation of the electric motor, for charging the electric energy storage device with the electric energy generated by the electric generator, depending upon the amount of electric energy stored in the electric energy storage device immediately after the termination of the operation of the electric motor. This arrangement permits a sufficiently high rate of rise of the engine assisting drive torque of the electric motor, even where the engine assisting operation of the electri
Ichioka Eiji
Mikami Tsuyoshi
Morisawa Kunio
Camby Richard M.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Toyota Jidosha & Kabushiki Kaisha
LandOfFree
Controller for hybrid vehicle wherein one and the other of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Controller for hybrid vehicle wherein one and the other of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Controller for hybrid vehicle wherein one and the other of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2503586