Abstract: A hydraulic pressure control apparatus for a torque converter includes a relay valve switching levels of a hydraulic pressure in the hydraulic power transmission chamber and establishing selective connections between a cooler and the hydraulic power transmission chamber or between the cooler and a hydraulic pressure supply source of which a flow amount of the operational fluid is regulated by a first orifice, an electronic control unit controlling operations of the relay valve, a hydraulic pressure declination determining portion judging whether the hydraulic pressure of the hydraulic pressure supply source is lower than a threshold value based on a predetermined vehicle state, and a switching command outputting portion outputting a command to connect the cooler and the hydraulic pressure supply source by the relay valve when the hydraulic pressure declination determining portion determines that the hydraulic pressure of the hydraulic pressure supply source is lower than the threshold value.

Abstract: Prior to transitioning a multiple-displacement engine from a full-displacement engine operating mode to a partial-displacement engine operating mode, a base slip rate of a torque converter coupled to the engine engine is increased by a predetermined slip rate offset. The engine is then transitioned to partial-displacement mode upon the earlier of either achieving the desired offset slip rate, or once a maximum time delay has occurred since the slip rate offset was enabled. An offset slip rate is maintained throughout partial-displacement engine operation, and through a transition back to a full-displacement mode. The slip rate offset is removed or disenabled once the engine is again operating in the full-displacement mode. The slip rate offset is either a calibratable constant or is determined as a function of one or more suitable engine or vehicle operating parameters affecting vehicle NVH levels, such as engine speed and vehicle speed.

Abstract: A control system is disclosed for minimizing the driveline vibrations in a hybrid electric vehicle during engine engagement. The control system involves determining the speed of the electric motor and taking the derivative of the speed to determine the acceleration. A signal representing the acceleration is created. The acceleration signal is filtered. The filtered acceleration signal is used to calculate a feedback control term through a controller. The controller can be either a PD controller or a PID controller with a low integral gain. The feedback control term is used to adjust the output torque of the electric motor to suppress the vibrations caused by engine engagement.

Abstract: The invention relates to a motor vehicle comprising a drive motor and a gearbox with a device for automatically actuating a clutch in the drivetrain, and to a control method. According to said method, if the gear ratio is less than a threshold value and the actuation of a driving pedal is not equal to zero and is less than a threshold value, warning measures are initiated to alert the driver to misuse.