Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Patent
1998-04-27
2000-03-28
Cuchlinski, Jr., William A.
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
701 51, 701110, 477 34, 477 68, G06F 1700, G06F 1900, G06F 700
Patent
active
060443170
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns a method of elimination of the phenomenon of pumping of a motor vehicle with automatic transmission, as well as a motor vehicle employing that method.
2. Discussion of the Background
The pumping phenomenon is common in the field of motor vehicles with automatic transmission. It involves an instability of the automatic transmission, which in some circumstances changes constantly from one ratio to the higher ratio and vice versa.
This phenomenon generally occurs when a vehicle equipped with an automatic transmission is subjected to a certain level of resistant forces caused, in practice, by a sloping road, a presence of very strong wind, a sizable load of the vehicle, or even when the vehicle is traveling at a high altitude, that is, under relatively weak atmospheric pressures.
A theoretical solution to this problem consists in preventing any shift to the higher gear ratio if the acceleration of the vehicle on that higher ratio would be negative, and if the vehicle is subjected to strong resistant forces.
A partial solution to the pumping problem was introduced, in practice, by the method of adaptive scheduling of shifting down, described in patent U.S. Pat. No. 5,241,476 of the Chrysler Corporation. According to that document, the method consists in determining whether the vehicle could maintain its speed on the higher ratio and, if not, preventing the shift from the higher ratio. That method resorts to the calculation of acceleration of the vehicle on the higher ratio, but without precisely knowing the weight of the vehicle. The result of the determination is therefore erroneous. Furthermore, according to that document, only cases of pumping between third and fourth gear are eliminated, while the other cases of pumping can occur.
In addition, this method consists in locking the ratio engaged if the calculations lead to an acceleration that would be negative on the higher ratio. That criterion leads to untimely lockings on the ratio engaged, once the acceleration value calculated is slightly negative. Likewise, if acceleration ranges around zero, it would be randomly switched from a nonlocking condition to a locking condition, and so on.
SUMMARY OF THE INVENTION
The invention is, consequently, intended to propose a method of driving the gear of a vehicle with automatic transmission, making it possible to avoid the pumping phenomenon efficiently, regardless of the ratio engaged and the number of gear ratios.
Another object of the invention is to propose a method making possible a less erratic determination of the pumping risk, so as to optimize operation of the automatic transmission.
For that purpose, the invention concerns a method of elimination of the phenomenon of pumping of a motor vehicle with automatic transmission, characterized in that it includes the stages consisting of: vehicle, the current transmission ratio, the engine speed and the angle of opening of the engine throttle valve; vehicle would experience on the higher ratio; possibility of having a pumping phenomenon on the higher ratio, called "pumping risk;" from the higher ratio, intended to be applied to the transmission control system.
According to other characteristics of the method of the invention:
in order to determine the possibility of having a pumping phenomenon on the higher ratio, a fuzzy logic technique is used, including the stages consisting of: higher ratio in a negative fuzzy subsystem defined by a given acceleration threshold; fuzzy subsystem defined by a lower threshold of resistant forces and by a higher threshold of resistant forces; pumping risk on the higher ratio as being the minimum value of torque of the degrees of membership; acceleration on the higher ratio are determined by an adjustment and depend on the current ratio engaged;
determination of the weight of the vehicle includes the stages consisting of: vehicle; valve, engine speed and reduction ratio of the transmission on the current ratio; given times; recursive least squares of
REFERENCES:
patent: 5067374 (1991-11-01), Sakai et al.
patent: 5079705 (1992-01-01), Sakai et al.
patent: 5479345 (1995-12-01), Amsallen
Arthur Gertrude
Cuchlinski Jr. William A.
Renault
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