Interrelated power delivery controls – including engine control – Transmission control – Including fluid drive
Reexamination Certificate
2000-01-04
2001-02-06
Marmor, Charles A. (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
Including fluid drive
C477S063000, C477S065000, C477S080000
Reexamination Certificate
active
06183391
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control apparatus for controlling an operation of an automatic transmission for a vehicle, and more particularly, to a control apparatus for disengaging a lock-up clutch when an abrupt brake is applied in order to prevent an engine stall.
2. Background Art
Japanese Patent Application Laid-open No. Toku Kai-Hei 2-227342 discloses a drive system having a torque converter with a lock-up clutch, a planetary gear type forward and reverse changeover apparatus and a continuously variable transmission (CVT). The drive system is designed to disengage the lock-up clutch of the torque converter when an anti-lock brake (ABS) operates, that is, when the wheel slip is properly controlled, so that an engine stall is prevented.
However, particularly when a vehicle is abruptly braked on a road surface having low friction coefficient, even if the vehicle is equipped with ABS, depending upon braking conditions, there is a possibility that a wheel is locked to stop the rotation before the lock-up clutch is released and as a result an engine stall occurs.
In order to solve this problem, Japanese Patent Application Laid-open No. Toku-Kai-Hei 4-357357 proposes a drive system in which both forward clutch and reverse brake of the forward and reverse changeover apparatus are set to a disengagement condition. However, releasing both of the forward clutch and reverse brake may cause an overrun of the engine, in case where a driver depresses an accelerator pedal to accelerate the vehicle immediately after an abrupt braking.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a control apparatus of an automatic transmission capable of preventing an engine stall when an abrupt brake is applied and also capable of preventing an overrun of the engine when an accelerator pedal is depressed after the abrupt brake is applied. In order to attain the object, the control apparatus for an automatic transmission of a vehicle having a forward friction element for engaging or disengaging a turbine shaft with the automatic transmission in a forward running direction and a lock-up clutch for directly transmitting a rotation of an engine to the turbine shaft, comprises an abrupt deceleration control means for disengaging the forward engagement element and the lock-up clutch when an abrupt deceleration of the vehicle is detected, and a restoring means for canceling the abrupt deceleration control means and for restoring the forward friction element to an engagement state when an accelerator pedal is depressed for acceleration.
REFERENCES:
patent: 5161432 (1992-11-01), Matsumoto et al.
patent: 5362287 (1994-11-01), Tanaka et al.
patent: 5480363 (1996-01-01), Matsubara et al.
patent: 5626536 (1997-05-01), Kono et al.
patent: 5667458 (1997-09-01), Narita et al.
patent: 63-303258 (1988-12-01), None
patent: 2-227342 (1990-09-01), None
patent: 4-357357 (1992-12-01), None
Marmor Charles A.
Ruji Jukogyo Kabushiki Kaisha
Smith , Gambrell & Russell, LLP
Waddell Tisha D.
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