Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Patent
1995-10-02
1998-08-04
Nguyen, Tan Q.
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
701 55, 701 56, 701 61, 477 43, 477 46, 477 49, F16H 6104, B60K 4112
Patent
active
057909687
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to control system and method for a vehicle having a continuously variable transmission between an engine and a continuosly variable drive axle.
BACKGROUND ART
In the case of a transmission (CVT), there are hitherto known the following problems that arise during shifting at a high shift speed. feeling of speed decrease (hesitation) during downshift, and a feeling of dashing out during upshift. the vehicle speed, resulting in an unnatural feeling characteristic of CVT.
By contrast to this, a system disclosed in an official gazette of Japanese Patent Provisional (Unexamined) Publication No. 62-149526, for example, is arranged to determine the shift speed from a deviation between a steady state transmission ratio as a final target and a current transmission ratio, and a correction quantity determined by a throttle opening speed.
However, the system of the above-mentioned official gazette seems insufficient to solve the problem mentioned in (1) above, for the following reason.
An inertia torque TI during shifting is determined by the following equations, assuming that an engine inertia IE is predominant: engine, and NE is a revolution speed or a number of revolutions of the engine (a transmission's input shaft revolution speed).
Supposing dNo/dt<<dNE/dt during a shift operation, the following equation is obtained from NE=i.multidot.No: di/dt is the shift speed, i is the transmission ratio, and No is a transmission's output shaft revolution speed.
Therefore, in order to control the shift speed in consideration of the inertia torque, the transmission's output shaft revolution speed No (namely the vehicle speed) must be taken into account.
As shown by characteristics at low and high vehicle speeds in FIG. 10, the inertia torque differs between the low vehicle speed operation and high vehicle speed operation, even if the width of the transmission ratio is the same. The system disclosed in the above-mentioned official gazette controls with the same shift speed nevertheless. Specifically in the high vehicle speed operation, therefore, the output torque is diminished by an increase of the engine revolution speed. This system suffers such a disadvantage.
As to the problem mentioned in (2), the system recited in the above-mentioned official gazette is arranged to modify the shift speed earlier when a driver's intention of rapid acceleration is ascertained by the throttle opening speed.
However, the use of the throttle opening may cause a feeling of rapid increase of the engine revolution specifically on the high opening side because the relation between the driving force and the throttle opening is not linear, and accordingly an intention of acceleration and an actual acceleration do not coincide.
SUMMARY OF THE INVENTION
In view of the problems mentioned above, one of the objects of the present invention is to control an inertia torque during shifting to a desired value in a vehicle equipped with a continuously variable transmission, and to improve the drivability by controlling the shift speed in consideration of a driver's intention. A more concrete object of the present invention is to provide vehicle control system and method that can control the inertia torque to the desired value and better reflect the driver's intention reflected, by determining the shift speed as a decreasing function with respect to the current transmission ratio i and the output shaft revolution speed No, and as an increasing function with respect to said coefficient TTINR.
It is another object of the present invention to provide vehicle control system and method that can take account of a step in the transmission ratio by computing the coefficient TTINR based on a relationship between the current transmission ratio and a transmission ratio in a steady state condition.
It is still another object of the present invention to provide vehicle control system and method that can take account of a step of an output (horsepower) and provide a characteristic corresponding to a vehicle behavior
REFERENCES:
patent: 4827803 (1989-05-01), Miyawaki
patent: 4833944 (1989-05-01), Tanaka
patent: 5009127 (1991-04-01), Morimoto et al.
patent: 5009129 (1991-04-01), Morimoto et al.
patent: 5020392 (1991-06-01), Morimoto
patent: 5156572 (1992-10-01), Morishige
patent: 5382205 (1995-01-01), Togai et al.
Eggert, U. "CVT-Gatriebe: Elektronische Regalung und Fahrdynamlk", VDI Zeitschrift-Special Antriebstechnlk, No. 1, Duesseldorf, .Mar. 1992, pp. 26-49.
Hosono Masayuki
Kashiwabara Masuo
Yuasa Hiroyuki
Nguyen Tan Q.
Unisia Jecs Corporation
LandOfFree
Control system and method for vehicle with continuously variable does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Control system and method for vehicle with continuously variable, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Control system and method for vehicle with continuously variable will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1191060