The present invention relates to a method for controlling a clutch arrangement (102) of a vehicle transmission (100) arranged within a gearbox housing (104) of a vehicle, the clutch arrangement being connected to a pneumatically controlled actuator arrangement (106) for controllably arrange the clutch arrangement between a closed position and an open position, wherein the vehicle transmission further comprises at least one rotatable transmission component (108, 108, 108) configured to assume an engaged state, a disengaged state and an at least partially engaged state. By means of the method, the rotatable transmission component is arranged to be positioned in the at least partially engaged state for increasing the heat within the gearbox housing.

A vehicle includes an engine, a transmission, and a controller. The transmission has clutches, a circuit configured to transport fluid to the clutches, a pump configured to circulate the fluid through the circuit, and an accumulator disposed along the circuit. The controller is programmed to, responsive to an engine start and a fluid temperature being less than a temperature threshold, discharge the accumulator to prime the pump.

A vehicle includes an engine, a transmission, and a controller. The transmission has clutches, a circuit configured to transport fluid to the clutches, a pump configured to circulate the fluid through the circuit, and an accumulator disposed along the circuit. The controller is programmed to, responsive to an engine start and a fluid temperature being less than a temperature threshold, discharge the accumulator to prime the pump.

A method for controlling a hydraulic pressure refilling operation for an engine clutch of a vehicle includes determining whether the vehicle travels using power of a driving motor with an engine clutch maintained in a disengaged state, and upon determining that the vehicle travels using power of the driving motor with the engine clutch maintained in the disengaged state, determining whether loss of hydraulic pressure has occurred, and upon determining that loss of hydraulic pressure has occurred, controlling a hydraulic pressure refilling operation such that working fluid in a reservoir is supplied to the actuator with the engine clutch in an engaged state, and controlling the driving motor so that the driving motor outputs a compensated torque by compensating for an effect of a load torque, generated by a non-operating engine, on a torque of the driving motor.

A method for controlling a hydraulic unit with a rotational-speed-controlled pump which, at an outlet side, provides at least two fluid flows in a manner switched by means of switching valves actuating at least one slave cylinder and for providing a volume flow which is controlled based on a rotational speed of the pump. To set the volume flow, an efficiency of the pump is calculated base on a comparison of a known slave cylinder volume of the at least one slave cylinder and a quantity of fluid of the pump for the filling of the at least one slave cylinder.

A method for adjusting and adapting an operating point of a hydraulic actuator arrangement, in which a volume flow source is connected to a hydraulic cylinder via a pressure line that is filled with a hydraulic fluid. The method includes regulating a volume of the hydraulic fluid by the volume flow source, wherein an operating point of a position of the actuator arrangement corresponds, with respect to a predefined parameter, to a device which is to be actuated by the actuator arrangement. A modified volume of the hydraulic fluid which is necessary to adjust the operating point is derived from a rotational position of a volume flow source motor and/or of the volume flow source.

A method for CVT low oil pressure input clutch fill compensation includesperforming a garage shift when a modeled fill pressure is equal to a commanded modeled fill pressure. Then the line pressure is checked to determine if it is less than the commanded fill pressure when performing the garage shift. If so, then the modeled fill pressure is set to the line pressure and the primary and secondary actual pulley pressures are read by sensing devices. Next, the primary and secondary commanded pulley pressures are checked to determine if they are greater than the modeled fill pressure. If so, then a first dPressure value for the flow rate model based on the lowest of the modeled fill pressure, the primary actual pulley pressure, or the secondary actual pulley pressure is determined and it is used to compensate the flow rate model.

In order to pre-stage a clutch piston in preparation for clutch engagement, a controller commands a high current to a Casting Integrated Direct Acting Solenoid (CIDAS) valve. This staging is performed in two distinct phases wherein the current is higher in the first phase than in the second phase. Staging the piston in this manner reduces the staging time and reduces the variability of the staging time. The duration of the first phase may be adjusted based on a number of parameters including, the length of a preceding engine off period, the number of clutch applications since the engine off period, a fluid temperature, and a length of time since a preceding engagement of the clutch.

A system and method for determining filling parameters of a wet clutch system used with a transmission is provided. The method comprises the steps of collecting information about the torque output of the torque converter of the transmission during a filling process associated with the wet clutch system, analyzing the signal associated with the torque output of the torque converter within a time period of the filling process associated with the wet clutch system, and identifying when the signal associated with the torque output of the torque converter changes with respect to the time period of the filling process of the piston to determine a filling parameter associated with the wet clutch system. The system and method eliminates a need for recalibrating the transmission and accommodates production variances for components and assembly of systems using wet clutch systems.

A method for controlling a hydraulic unit with a rotational-speed-controlled pump, which, at an outlet side, provides at least two fluid flows in a manner switched by means of switching valves, for actuating at least one slave cylinder and for providing a volume flow which is controlled based on a rotational speed of the pump. To set the volume flow, an efficiency of the pump is calculated based on a comparison of a known slave cylinder volume of the at least one slave cylinder and a quantity of fluid of the pump for the filling of the at least one slave cylinder.