A control system operates a power train of a work vehicle. The system includes a transmission arrangement which transfers power from an engine to an output shaft of the vehicle to drive the vehicle in a first or second direction according to at least one forward or reverse modes. The arrangement includes a forward directional clutch and a reverse directional clutch, and a controller. The controller is configured to determine if one of the clutches is engaged; evaluate a speed of the engine; and provide a torque command to engage the other of the clutches to slow the speed of the engine when a shuttle shift is initiated, or when the speed of the engine exceeds a predetermined speed threshold.

A method of operating a vehicle having an engine, a throttle valve and a throttle operator. A continuously variable transmission operatively connected to the engine has a driving pulley, a driven pulley, and a belt operatively connecting the driving and driven pulleys. A ground engaging member is operatively connected to the driven pulley. A piston is operatively connected to the driving pulley for applying a piston force thereto and thereby changing an effective diameter of the driving pulley. A control unit controls actuation of the piston and the piston force. The method includes detecting a stall condition indicative of the vehicle being stalled, and, responsive to the detection, setting the piston force to be zero.

A method of operating a vehicle having an engine, a throttle valve and a throttle operator. A continuously variable transmission operatively connected to the engine has a driving pulley, a driven pulley, and a belt operatively connecting the driving and driven pulleys. A ground engaging member is operatively connected to the driven pulley. A piston is operatively connected to the driving pulley for applying a piston force thereto and thereby changing an effective diameter of the driving pulley. A control unit controls actuation of the piston and the piston force. The method includes detecting a stall condition indicative of the vehicle being stalled, and, responsive to the detection, setting the piston force to be zero.

A method and system for selecting a speed ratio for a continuously variable transmission (CVT) of a vehicle during braking. The method and system includes determining a Current Actual Speed Ratio of the CVT when the distance of a brake pedal travel exceeds a predetermined distance, determining, by a transmission control module (TCM), an amount of Available Speed Ratio Change (r), a Current Ratio Change Capability (Current-{dot over (r)}), and a Predictive Ratio Change Capability (Predictive-{dot over (r)}). The method further includes the TCM calculating a Time to Reach the Minimum Under-drive Ratio (t.sub.UD), calculating a Predicted Velocity of the Vehicle (v.sub.Pr) using (t.sub.UD), determining a Desired Speed Ratio of the CVT using the Predicted Velocity of the Vehicle (v.sub.Pr), and actuating the CVT to the Desired Speed Ratio.

A method of adjusting and using operating parameters of a transmission of a vehicle may include accessing a stored list of clutch parameters, performing a dynamic condition procedure while the vehicle is driven to revise minimum on-coming apply pressure for each friction element based on a sensed performance of an element within the vehicle powertrain, storing the modified minimum on-coming apply pressures, and operating the vehicle. A related transmission control device operates a transmission using parameters obtained during a dynamic condition procedure.

A method of adjusting and using operating parameters of a transmission of a vehicle may include accessing a stored list of clutch parameters, performing a dynamic condition procedure while the vehicle is driven to revise minimum on-coming apply pressure for each friction element based on a sensed performance of an element within the vehicle powertrain, storing the modified minimum on-coming apply pressures, and operating the vehicle. A related transmission control device operates a transmission using parameters obtained during a dynamic condition procedure.

A recreational vehicle is provided including a power source, such as an engine or an electric motor, and a transmission having a variable gear ratio. A sub-transmission coupled to an output of the transmission includes a plurality of selectable gear configurations including park gear and at least one of a forward gear, a neutral gear and a reverse gear. An electronic controller is operative to electronically control the gear configuration of the sub-transmission in response to a set of conditions.

A control device for an automatic transmission of a vehicle includes a shift control section including; a deceleration state judging section configured to judge whether a deceleration of the vehicle is a gentle deceleration state or a sudden deceleration state, and a downshift control section configured to command a plural stage downshift to downshift from a current shift stage of the automatic shift mechanism to a target shift stage that is lower than the current shift stage by two stages or more when the deceleration state judging section judges the sudden deceleration state.

A control device for an automatic transmission of a vehicle includes a shift control section including; a deceleration state judging section configured to judge whether a deceleration of the vehicle is a gentle deceleration state or a sudden deceleration state, and a downshift control section configured to command a plural stage downshift to downshift from a current shift stage of the automatic shift mechanism to a target shift stage that is lower than the current shift stage by two stages or more when the deceleration state judging section judges the sudden deceleration state.

A mechanical supercharging system includes a stepped transmission that connects a crankshaft of an internal combustion engine with driving wheels, a centrifugal supercharger including a rotary drive shaft connected to the crankshaft, a variable speed ratio device that changes a speed ratio of the rotary drive shaft to the crankshaft, the variable speed ratio device being provided between the crankshaft and the rotary drive shaft; and a control device configured to control the speed ratio. The control device increases the speed ratio during the upshift operation more than the speed ratio before start of the upshift operation.