A vehicle having a clutch which connects an engine with a driveline which includes a multi-ratio gearbox, the clutch having an actuator which can be operated by a vehicle driver to engage and disengage the clutch, the actuator also having a control system arranged to move the clutch between fully engaged and fully released positions through a range of positions allowing variable levels of clutch slip in order to automatically reduce torsional vibrations in the driveline. The control system is configured to recognize a plurality of predetermined Vehicle Operation Modes defined by the combination of a Clutch Slip Status criterion as hereinbefore defined with one or more of the hereinbefore defined operating criteria of Manual Clutch Position Control Input Interface Status, Release Bearing Position Status and Slip Velocity Demand Status and, dependent on the recognized Vehicle Operation Mode, the control system applies a different clutch control strategy to achieve the required level of clutch slip to damp vibration in the driveline and provide transition between the different Vehicle Operation Modes without exciting an uncomfortable level of vibration in the driveline.

A vehicle power transmission system includes: a transmission; a shift actuator; a clutch; a clutch actuator for mutually switching between the transmission and the shutting off of a driving force at the clutch; and a control device being configured to, when having detected that the vehicle is in the travelling state and that the clutch actuator is abnormal by use of the travelling state detection sensor and the CA abnormality detection sensor, control the operation of the shift actuator and cause the selected gear stage in the transmission to be shifted into neutral before the vehicle comes to a stop while shifting the selected gear stage in the transmission into a gear stage having a lower gear ratio.

A control apparatus for a power transmission system is provided. The control apparatus includes an electronic control unit. The electronic control unit is configured to, when a discharge flow rate of a mechanical oil pump is smaller than a predetermined flow rate and an electric oil pump is being driven while a vehicle is traveling, determine whether a decrease in the operating hydraulic pressure has occurred. The electronic control unit is configured to, when a first engagement device is controlled from a released state toward an engaged state, control a first control pressure such that the first control pressure in a case where a decrease in a operating hydraulic pressure has occurred is lower than the first control pressure in a case where a decrease in the operating hydraulic pressure does not occur.

A vehicle control device is provided with a friction clutch for engaging and disengaging a motor/generator and a drive wheel, a mechanical oil pump driven by the motor/generator to supply hydraulic oil pressure to the friction clutch, an electric oil pump driven by an electric motor to supply hydraulic oil pressure to the friction clutch, and a control unit. The control unit stops a motor/generator when a vehicle stops; maintains a release of a friction clutch when slack in the stroke is eliminated by the hydraulic oil pressure from the electric oil pump; raises a rotational speed of the motor/generator toward a target rotational speed upon a request to cancel stoppage of the motor/generator; and restricts the torque to be less than the motor generator torque at which the target rotational rate can be maintained when the rotational rate of the motor/generator is raised toward the target rotational rate.

A vehicle control method is provided for controlling a vehicle having a friction clutch configured to switch between engagement and disengagement between a motor/generator and a drive wheel. The vehicle control method includes maintaining a friction clutch disengaged with slack eliminated in a stroke while the vehicle is stopped, reducing a motor rotational speed using a predetermined rotational speed as a target motor rotational speed in response a request to stop a motor/generator upon determining the motor rotational speed of the motor/generator is greater than the predetermined rotational speed, and when the motor rotational speed has reached the predetermined rotational speed, reducing the motor rotational speed toward zero while limiting the torque of the motor/generator.

A method may be provided for correcting a raw signal supplied by a pressure sensor in an all wheel drive system having a hydraulic pump and a hydraulic fluid. The method may include measuring the raw signal supplied by the pressure sensor, determining when the all wheel drive system is in a state where the hydraulic fluid is at a known pressure determined independently from the pressure sensor, determining a new zero-point offset by comparing the raw signal to a voltage value associated with the known pressure, and creating a corrected voltage signal by adjusting the raw signal based on the new zero-point offset. This corrected voltage signal may be converted into a pressure reading for controlling the all wheel drive system.

A dual-clutch transmission includes a hydraulic system for actuating hydraulic cylinders of the clutches and the shifting elements. The hydraulic system has a pressure accumulator providing an accumulated pressure in the hydraulic system, and control valves actuatable by a control unit and respectively arranged in pressure lines routed to the hydraulic cylinders of the clutches to adjust the hydraulic pressure applied to the clutches. Pressure sensors associated with the control unit detect the hydraulic pressure. The control unit activates a pressure reduction mode when detecting a long vehicle downtime, and the accumulated pressure can be reduced in the pressure reduction mode, in which the control unit continuously opens the control valve associated with one clutch. Additionally, the pressure sensor associated with the first clutch together with the control unit is integrated into a control circuit in which the first pressure sensor assumes the detection of the actual accumulated pressure value.

A diagnostic method of determining clutch failure of a dual clutch transmission (DCT) includes comparing, by a controller, a wheel torque of a vehicle with a driving load torque of the vehicle, confirming, by the controller, whether or not the vehicle is driving, if, as a result of comparing step, the wheel torque is greater than the driving load torque, releasing, by the controller, a gear engaged with a non-drive shaft, if, as a result of the confirming step, the vehicle is in a stopped state, reconfirming, by the controller, whether or not the vehicle is driving, after the releasing step, and judging, by the controller, that a transmission clutch of the non-drive shaft fails, if, as a result of the reconfirming step, the vehicle is driving.

A method for preventing overheating of a clutch for a vehicle may include determining, by a controller, whether a state of the vehicle satisfies a hill hold condition; acquiring, by the controller, a temperature of a clutch between an engine and a transmission when the hill hold condition is satisfied; applying, by the controller, a first torque having a predetermined square wave shape to the clutch when the temperature of the clutch reaches a first temperature; and applying, by the controller, a second torque having a predetermined sine wave shape to the clutch when the temperature of the clutch reaches a second temperature higher than the first temperature.

A diagnostic method of determining clutch failure of a dual clutch transmission (DCT) includes comparing, by a controller, a wheel torque of a vehicle with a driving load torque of the vehicle, confirming, by the controller, whether or not the vehicle is driving, if, as a result of comparing step, the wheel torque is greater than the driving load torque, releasing, by the controller, a gear engaged with a non-drive shaft, if, as a result of the confirming step, the vehicle is in a stopped state, reconfirming, by the controller, whether or not the vehicle is driving, after the releasing step, and judging, by the controller, that a transmission clutch of the non-drive shaft fails, if, as a result of the reconfirming step, the vehicle is driving.