Abstract: A continuously variable transmission control system determines the desired speed ratio for a continuously variable transmission from various input data received from the vehicle and operator. The desired speed ratio is compared with a commanded speed ratio to provide an error signal which establishes a new commanded speed ratio for the continuously variable transmission. The comparing process of desired speed ratio to commanded speed ratio is repeated until the error signal is substantially null. Also, the control provides an adaptive modifier for the actuator of the continuously variable transmission such that a comparison of actual transmission ratio to commanded speed ratio will determine if an adaptive modification is necessary. The control further provides a step control function which is operable when the ratio of the continuously variable transmission is moving toward an underdrive ratio.

Abstract: A continuously variable transmission control system determines the desired speed ratio for a continuously variable transmission from various input data received from the vehicle and operator. The desired speed ratio is compared with a commanded speed ratio to provide an error signal which establishes a new commanded speed ratio for the continuously variable transmission. The comparing process of desired speed ratio to commanded speed ratio is repeated until the error signal is substantially null. Also, the control provides an adaptive modifier for the actuator of the continuously variable transmission such that a comparison of actual transmission ratio to commanded speed ratio will determine if an adaptive modification is necessary. The control further provides a step control function which is operable when the ratio of the continuously variable transmission is moving toward an underdrive ratio.

Abstract: A multi-ratio automatic transmission has a plurality of fluid operated clutching devices, a fluidic torque converter and a fluid operated torque converter clutch mechanism. During certain operational periods, a hot mode is invoked to eliminate certain heat sources and increase heat dissipation to thereby prevent the fluid temperature from exceeding a predetermined maximum temperature. The hot mode is invoked as a function of both the temperature of the transmission fluid and the rate of change of the fluid temperature.

Abstract: A control for an automatic transmission minimizes shift cycling between adjacent speed ratios due to non-ideal load conditions such as grade climbing and trailering. The control utilizes shift schedule data in formulating a determination of the ability of the vehicle to maintain current levels of performance if an upshift were to occur and inhibits such upshifts where the determination so indicates an inability to meet the criteria.