Methods and systems are provided for controlling and diagnosing one or more clutches in a transmission. In one example, a method for operation of a vehicle system is provided that includes at a diagnostic controller or processing unit independent from a driveline controller or processing unit, respectively, determining an engagement state of a clutch in a transmission of the vehicle system, wherein the engagement state is selected from a group of three or more clutch engagement states. The method further includes identifying an unauthorized clutch state based on the engagement state of the clutch and a speed of the vehicle and responsive to the identification of the unauthorized clutch state, operating the vehicle system in a fault state.

A method for operating a clutch of a drivetrain for a motor vehicle, in which at least one micro-slip of the clutch is adjusted in a targeted manner by means of an electronic computing device of the drivetrain, whereby the clutch is operated with the micro-slip during at least one operating phase, wherein an overpressing of the clutch is adjusted in a targeted manner by means of the electronic computing device), whereby the clutch is operated slip-free during at least one second operating phase that is different from the at least one operating phase.

A method for operating a drive train of a motor vehicle includes performing a startup operation of the motor vehicle or a stopping operation of the motor vehicle. A starting component (3) is engaged or bridged during the startup operation or the stopping operation of the motor vehicle. The startup operation is driven by a drive source (1). The method also includes comparing an actual value of an output shaft (22) based variable with a target value of the output shaft (22) based variable during the startup operation or the stopping operation and, on reaching or exceeding a specific deviation of the actual value from the target value, moving the starting component (3) into a slipping state. The starting component (3) transmits torque in the slipping state. A related drive train module for a motor vehicle is also provided.

In a clutch engagement control system for engagement and disengagement of transmission of a rotational force between a mainshaft and a countershaft, when clutch engagement control is executed based on the determination that rotational speeds of both the shafts agree with each other, even if unexpected variations in countershaft rotational speed result from torsion occurring downstream of the countershaft in a drive system and/or the like, smooth engagement control is implemented. A control value of countershaft rotational speed at each time is updated and managed. If a threshold value is exceeded by a difference between a countershaft rotational speed actual measured value and the preceding control value, the threshold value is added to the preceding value to obtain the control value. If the threshold value does not exceed the difference, the actual measured value at this time is set as a control value without any change.

A control strategy is provided for a hybrid vehicle that will increase drivability during low or decreasing driver demands. Coordination between shifting the transmission and stopping or (non-demand) starting of the engine can increase drivability. The vehicle includes a motor/generator with one side selectively coupled to the engine and another side selectively coupled to the transmission. The control strategy acts when an engine start or stop is requested while driver demand is decreasing and a shift of the transmission is demanded. To inhibit these events from proceeding simultaneously, the control strategy delays the engine from starting or stopping until the transmission has finished shifting, or vice versa.

A saddle-riding type vehicle includes an automatic clutch mechanism configured to be activated by an actuator which enables a push start to be executed, so that even when a charged capacity of a battery is reduced, an engine can be started. A control unit of the vehicle proceeds to a push start control mode when an engine stopped state detection portion detects a stopped state of an engine, a vehicle stopped state detection portion detects a stopped state of the saddle-riding type vehicle, and a gear selected state detection portion detects a state in which any one of gears of a transmission is selected. In the push start control mode, the control unit applies a clutch to start the engine when a vehicle speed detection portion detects a predetermined vehicle speed or faster, and a cutoff switch state detection portion detects a change in state of a cutoff switch.

A method to control a road vehicle provided with a clutch, which connects an internal combustion engine to drive wheels and is arranged upstream of a servo-assisted transmission; the control method comprises the steps of: checking whether the tyres of the drive wheels are close to a grip limit; and opening the clutch so that the clutch transmits a torque to the drive wheels with a slip of the clutch that is constant and other than zero when the tyres of the drive wheels are close to the grip limit.

A control apparatus for a vehicle provided, with a step-variable transmission, includes: a feedback control portion; an input torque resetting control portion; a target input torque setting portion operated upon an increase of the accelerator pedal operation amount in the process of the shift-down action in a power-off state of the vehicle, to restrict an amount of increase of the input torque target value with respect to an amount of increase of an operator-required input torque value, so as to keep the target value not larger than an upper limit value until termination of the input torque resetting control; and an actual input torque increasing portion operated upon the increase of the accelerator pedal operation amount prior to initiation of the inertia phase, to implement an input torque increasing control to control the input torque so as to be larger than the target value, prior to the inertia phase initiation.

Lock-up clutch engagement hydraulic pressure learning control can be precisely performed by starting lock-up clutch engagement control and executing the lock-up clutch engagement hydraulic pressure learning control after execution of shift control is completed, in a case where the lock-up clutch engagement control is limited in a shift stage before execution of the shift control, when the shift control is executed in a state where a multi-disc lock-up clutch is released. Meanwhile, a decrease in fuel efficiency performance and a direct steering feeling is minimized by starting the lock-up clutch engagement control during shift control in a case where the lock-up clutch engagement control is not limited.

A brake torque distribution system for a vehicle can include a braking system and a controller. The controller can be configured to signal a clutch of the vehicle powertrain to move to the engaged position such that the front wheels are rotationally coupled to the rear wheels and the brake torque applied to the front wheels by the braking system is transmitted to the rear wheels. The controller can be configured to signal the clutch to move to the engaged position based on an inclination angle signal received by the controller and indicative of an angle of inclination of the vehicle, a selected gear signal received by the controller that is indicative of the reverse gear ratio being selected in the powertrain, and a load signal received by the controller and indicative of a load applied to a portion of the vehicle adjacent to the rear wheels.