Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Electric vehicle
Reexamination Certificate
2001-09-12
2003-09-30
Camby, Richard M. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Electric vehicle
C701S070000, C180S065230
Reexamination Certificate
active
06629024
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
1. Field of Art of the Invention
The present invention relates to a control apparatus for an automotive vehicle to be driven by a variable-cylinder engine and an electric motor or a motor/generator as drive power sources, and a control apparatus for the variable-cylinder engine, and more particularly to techniques for improving fuel economy of the vehicle.
2. Prior Art
There is known a hybrid drive system for an automotive vehicle, wherein a power transmitting mechanism connected to drive wheels is connected to an engine and an electric motor or a motor/generator. JP-A-11-350995 discloses an example of such a hybrid drive system, which uses a variable-cylinder engine which is selectively operable in one of a full-cylinder operating state and a partial-cylinder operating state (reduced-cylinder operating state). All of the cylinders of the engine are operated in the full-cylinder operating state, and some of the cylinders are operated in the partial-cylinder operating state. The present hybrid drive system is further arranged such that a kinetic energy of the vehicle during deceleration thereof is converted by regenerative braking operation of the electric motor into an electric energy, which is stored for use by the electric motor to provide an assisting drive torque upon starting of the vehicle, for instance, to thereby improve the fuel economy of the vehicle.
[Problem Solved by the Invention]
However, a need to improve the fuel economy of the vehicle is unlimited, and there has been a demand for a further improvement in the fuel economy of such a vehicle using a variable-cylinder engine and an electric motor as drive power sources, as described above.
The present invention was made in view of the background situation described above. It is therefore an object this invention to provide a control apparatus for a variable-cylinder engine or an automotive vehicle control apparatus, which apparatus permits a further improvement in the fuel economy of the vehicle.
[First Solution for Solving the Problem]
The above object may be achieved according to the principle of this invention, which provides a control apparatus for a variable-cylinder engine, characterized by comprising (a) regenerative-braking-state detecting means for detecting a regenerative braking state of a vehicle, and (b) decompression-state setting means for placing selected ones of non-operating cylinders of the variable-cylinder engine in a decompression state, on the basis of the regenerative braking effect of the vehicle detected by the regenerative-braking-effect detecting means.
[Advantage of the First Invention]
In the present control apparatus, the decompression-state setting means is arranged to place appropriate ones of the non-operating cylinders of the variable-cylinder engine in the decompression state, on the basis of the regenerative braking state of the vehicle detected by the regenerative-braking-state detecting means in the decompression state, so that only a required minimum number of the non-operating cylinders of the variable-cylinder engine
10
is/are placed in the decompression state, depending upon the detected regenerative braking state of the vehicle, making it possible to not only improve the fuel economy of the vehicle but also assure sufficient engine braking of the vehicle.
[Other Forms of the First Invention]
Where the variable-cylinder engine has a pair of banks each of which has a plurality of cylinders and which are operable independently of each other, the decompression-state setting means is preferably arranged to place both of the two banks of the variable-cylinder engine in the compression state when the regenerative-braking-state detecting means has not detected a regenerative braking state of the vehicle, and place one of the two banks of the variable-cylinder engine in the compression state and the other bank in the decompression state when the regenerative-braking-state detecting means has detected a regenerative braking state of the vehicle. In the decompression state, the cylinder chamber is in a non-compressed state even in the compression stroke. While the vehicle is not placed in a regenerative braking state, the engine provides an appropriate engine-braking effect since the two banks are both placed in the compression state. While the vehicle is placed in a regenerative braking state, on the other hand, the engine-braking effect is reduced by an amount corresponding to the amount of regenerative braking effect, since one and the other of the two banks are placed in the compression state and the decompression state, respectively, so that the total braking effect applied to the vehicle is substantially equal to that while the vehicle is not placed in the regenerative braking state, and the fuel economy is improved owing to the regeneration of an electric energy in the regenerative braking state.
The present control apparatus is preferably provided with engine-stop-mode detecting means for determining whether the vehicle is running in an engine-stop running mode, for instance, in a motor-drive mode or a fuel-cut mode, with the variable-cylinder being held at rest. In this case, the regenerative-braking-state detecting means is operated to detect the regenerative braking state of the vehicle, when the engine-stop-mode detecting means has detected that the vehicle is running in the engine-stop running mode. This arrangement is effective to improve the fuel economy of the vehicle and assure a sufficient engine braking effect, while the vehicle is running in the regenerative braking state and in the engine-stop mode with the variable-cylinder engine being held at rest.
The present control apparatus is preferably provided with engine-restart-possibility determining means for determining whether there is a possibility that the variable-cylinder engine will be restarted. In this case, the regenerative-braking-state detecting means is operated to detect the regenerative braking state of the vehicle, when the engine-restart-possibility determining means determines that there is a possibility that the variable-cylinder engine will be restarted. The decompression-state setting means is arranged to place one of the banks of the variable-cylinder engine in the compression state and the other bank in the decompression state, when the regenerative-braking-state detecting means has detected a regenerative braking state of the vehicle. In the regenerative braking state of the vehicle, therefore, one of the banks is placed in the compression state so that the variable-cylinder engine can be restarted in a short time when the engine is commanded to be restarted.
The present control apparatus is preferably arranged such that when the engine-restart-possibility determining means indicated above determines that there is not a possibility that the variable-cylinder engine will be restarted, the decompression-state setting means places both banks of the variable-cylinder engine in the compression state if the regenerative-braking-state detecting means has not detected a regenerative braking state of the vehicle, and places both banks of the variable-cylinder engine in the decompression state if the regenerative-braking-state detecting means has detected a regenerative braking state of the vehicle. This arrangement is advantageous in that an adequate engine braking effect is obtained while the vehicle is not placed in a regenerative braking state in which both banks are placed in the compression state, and that the amount of electric energy generated by the regenerative braking is maximized while the vehicle is placed in the regenerative braking state in which both banks are placed in the decompression state.
[Second Solution for Solving the Problem]
The object indicated above may also be achieved according to a second invention, which provides a control apparatus for a variable-cylinder engine to which an electric generator is operatively connected, characterized by comprising (a) electricity-generating-mode
Nagano Shuji
Tabata Atsushi
Camby Richard M.
Kenyon & Kenyon
Toyota Jidosha & Kabushiki Kaisha
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