Interrelated power delivery controls – including engine control – Plural engines – Electric engine
Reexamination Certificate
2000-11-29
2003-04-01
Bonck, Rodney H. (Department: 3681)
Interrelated power delivery controls, including engine control
Plural engines
Electric engine
C180S065230
Reexamination Certificate
active
06540642
ABSTRACT:
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. HEI 11-343825 filed on Dec. 2, 1999 including the specifications drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a vehicle control system and a vheicle control method capable of increasing the torque of a second drive source for power transmission to wheels upon a decrease in the torque of a first drive source for power transmission to wheels owing to shift operations by a transmission.
2. Description of the Related Art
There has been a well known synchro-mesh transmission as related art, which is provided with a clutch that is automatically engaged/disengaged on the torque transmission path leading to the transmission from the drive source. There are two types of the above-identified transmission: a semi-automatic type in which shift operation is manually performed by a driver such that engagement/disengagement of a clutch is automatically performed in association with the shift operation, and a fully automatic type in which shift operation is automatically performed and engagement/disengagement of a clutch is also automatically performed in association with the shift operation. The semi-automatic transmission may allow the driver to perform shift operations by his/her own intention, which hardly causes the driver to feel uneasiness owing to the drop in the driving force resulting from disengagement of the clutch during the shift operation. Meanwhile the fully automatic transmission may cause the drivers to feel uneasiness owing to the drop in the driving force resulting from the disengagement of the clutch during the shift operation because the shift operation is automatically performed irrespective of the driver's intention.
Japanese Patent Application Laid-Open No. HEI 11-141665 discloses an example of a transmission for a vehicle, which is capable of preventing the driver from feeling uneasiness during shift operations. The, transmission disclosed in the aforementioned related art has input and output shafts. The input/output shafts and the area therearound are provided with various types of gears for setting the forward speeds from first to fifth and reverse speed, as well as a plurality of synchromesh mechanisms for connecting/disconnecting the torque transmission path between various gears and the input shaft/output shafts. The transmission is further provided with an electric motor connected to the output shaft, which allows torque transmission, a clutch disposed between a crank shaft of an engine and the input shaft of the transmission, and a controller for controlling the engine, synchromesh mechanism, clutch, and electric motor. The controller is structured to receive input of signals from a shift position sensor, an accelerator opening sensor, a vehicle speed sensor and the like.
With the vehicle transmission disclosed in the aforementioned related art, the controller outputs a transmission signal in accordance with information such as of accelerator opening and vehicle speed in a vehicle running state upon engine torque transmission to wheels The clutch disposed between the engine and the transmission is then disengaged and the electric motor is driven to transmit the torque to the output shaft. Along with disengagement of the clutch, the synchromesh mechanism is actuated for gear shifting. The clutch is engaged and the electric motor is stopped so as to allow transmission of the engine torque to the wheels. The vehicle transmission as identified above transmits the torque of the electric motor to the wheels during gear shifting upon disengagement of the clutch so as not to allow transmission of the engine torque to the wheels. Therefore deterioration in the driving force can be suppressed by transmitting the torque of the electric motor to the wheels. Accordingly, the driver hardly feels uneasiness from the shifting operation.
The electric motor provided in the vehicle transmission as disclosed in the related art is intended to suppress a decrease in the torque transferred to the wheels during a shifting operation. The additional driving source just to suppress a decrease in torque, however, may increase the manufacturing cost and weight of the vehicle.
SUMMARY OF THE INVENTION
In view of the foregoing problems, it is an object of the invention to provide a vehicle control system capable of suppressing a decrease in torque transmitted to the wheels during a shifting operation without employing the additional drive source to suppress a decreasing torque.
In order to achieve the aforementioned object, the vehicle control system according to one aspect of the invention is structured such that the torque of a first drive source is transmitted to the wheels via a transmission, a clutch is provided on the torque transmission path leading to the transmission from the first drive source, and the clutch is disengaged upon a shifting operation of the transmission. In this vehicle control system, the torque of a second drive source is transmitted to the wheels to be driven without passing through the transmission. The torque transmitted from the second drive source to the wheels is increased upon a shifting operation of the transmission.
According to the aspect of the invention, the torque transmitted from the first drive source to the wheels is decreased during a shifting operation of the transmission. Meanwhile the torque transmitted from the second drive source to the wheels is increased in order to suppress a decrease in the driving force acting on the vehicle, as a whole. The second drive source preliminarily mounted on the vehicle serves to suppress a decrease in the torque transmitted to the wheels during a shifting operation. This may eliminate the need for employing an additional drive source for suppressing a decrease in torque during a shifting operation. As a result, the vehicle manufacturing cost and the vehicle weight can be reduced.
Alternatively the wheels may include first wheels and second wheels each having a different torque transmission path such that the degree of increase in torque transmitted from the second drive source to the second wheels during a shifting operation may be variable depending on whether torque is transmitted only to the first wheels during a shifting operation of the transmission, or to both the first and the second wheels during a shifting operation of the transmission. According to the above example, the torque transmitted from the second drive source to the second wheels during a shifting operation can be controlled depending on the driven state of the vehicle. As a result, this may prevent a change in the running performance of the vehicle between the state before shifting and the state during shifting.
When increasing the torque to be transmitted from the second drive source to the second wheels,upon a shifting operation of the transmission, the degree of increase in torque being transmitted to the first and the second wheels maybe set to be smaller than the degree of increase in torque being transmitted only to the first wheels.
According to the aforementioned structure, in the state where the torque of the second drive source is transmitted to the second wheels in accordance with a torque output request other than a shifting operation, an excessive increase in torque of the second wheels can be prevented even if the torque transmission to the second wheels is increased from a shifting operation. Slippage of the second wheels, thus, can be prevented.
An embodiment of this invention is not limited to a vehicle control system such as that described heretofore. Another embodiment of the invention includes, for example, a four-wheel-drive vehicle equipped with a vehicle control system and a vehicle control method.
REFERENCES:
patent: 4438342 (1984-03-01), Kenyon
patent: 5072815 (1991-12-01), Jarvis
patent: 5337848 (1994-08-01), Bader
patent: 5441462 (1995-08-01), Chan
patent: 5495906 (1996-03-01), Furutani
patent: 5713425 (1998-02-01), Busch
Bonck Rodney H.
Oliff & Berridg,e PLC
Pang Roger
Toyota Jidosha & Kabushiki Kaisha
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