A method and a system for controlling a gear of the two-speed gearbox and a vehicle is provided. The method for controlling a gear of a two-speed gearbox includes: determining a first target gear of the gearbox reflecting a current driving demand of a user according to a current vehicle-speed; and performing a gear intervention control of the gearbox based on at least one of the following aspects: position information of a drive gear-lever, a rotation-speed of a drive motor of a vehicle, and gear fault information of the gearbox, to shift the first target gear of the gearbox to a second target gear of the gearbox that matches with real-time operation conditions of the vehicle.

A method for operating a drive train having a power generator, a mechanical power transmission device, and a power receiver wherein the power transmission device is monitored to detect mechanical damage and/or the development of mechanical damage to the power transmission device, wherein detected damage and/or detected damage development is localized and the power generator, the power transmission device, and/or the power receiver are/is controlled such that a mechanical load at the localized damage location and/or damage development location is selectively reduced. A program product including program code sections with which such a method is feasible when the program product is executed on a programmable controller, a computer, or other programmable device.

A method and a system of diagnosing a vehicle oil leak are capable of detecting an oil leak state of transmission oil on the basis of logic. The method includes an operating condition determination step of determining, by a controller, whether a minimum operating condition of a vehicle is satisfied. The minimum operating condition is required to normally generate a target line pressure by operating an EOP. The method includes a counting step of counting, by the controller, an operating time of the EOP when the minimum operating condition is satisfied and includes an oil leak diagnosis step of diagnosing, by the controller, an oil leak when the counted continuous operating time of the EOP is a permissible time or more.

A method of detecting a failure of a hydraulic pump includes sensing a rotational speed of the engine, and a rotational speed of a rotating drivetrain component. A numerical difference between the rotational speed of the engine and the rotational speed of the rotating drivetrain component is calculated. The numerical difference is compared to a threshold value to determine if the numerical difference is less than the threshold value, or is equal to or greater than the threshold value. A failure of the hydraulic pump is identified when the numerical difference between the rotational speed of the engine and the rotational speed of the rotating drivetrain component is equal to or greater than the threshold value, and the transmission is positioned in the neutral gear mode. When a failure of the hydraulic pump is identified, the operation of the engine is stopped.

The present invention provides an automatic transmission capable of properly judging faults of a switching mechanism. A control part ECU of the automatic transmission TM has an actual change gear ratio calculating part 10 and a fault judging part 11. Under a condition that the control part ECU has recognized that the first brake device B1 is switched to a reverse rotation preventing state, if the actual change gear ratio is kept to be an actual change gear ratio prior to a reduce of a rotational speed of a drive source ENG when the rotational speed of the drive source ENG is reduced, then the fault judging part 11 judges that a first brake B1 has a fault.

A control device provided in a gear shifting device includes an electronic control unit. The electronic control unit determines whether an abnormality of the gear shifting device has occurred, performs a fail-safe process of switching the frictional engagement element corresponding to an abnormality to a disengaged state and fixing the gear shift ratio of the gear shifting device when it is determined that an abnormality has occurred, determines whether the abnormality has been relieved based on a behavior of an input signal at the time of operating a drive device of the frictional engagement element corresponding to an abnormality on condition that the frictional engagement element is maintained in the disengaged state after it is determined that the abnormality has occurred, and releases the fail-safe process when it is determined that the abnormality has been relieved.

A control device provided in a gear shifting device includes an electronic control unit. The electronic control unit determines whether an abnormality of the gear shifting device has occurred, performs a fail-safe process of switching the frictional engagement element corresponding to an abnormality to a disengaged state and fixing the gear shift ratio of the gear shifting device when it is determined that an abnormality has occurred, determines whether the abnormality has been relieved based on a behavior of an input signal at the time of operating a drive device of the frictional engagement element corresponding to an abnormality on condition that the frictional engagement element is maintained in the disengaged state after it is determined that the abnormality has occurred, and releases the fail-safe process when it is determined that the abnormality has been relieved.

A shift range control device controls a shift range switching system including an actuator, an output shaft, and a shift range switching mechanism. The shift range control device includes a target setting unit, a drive control unit, and an abnormality monitoring unit. The target setting unit sets a target shift range. The drive control unit controls the drive of the actuator so that the engagement member fits into the target valley portion, which is the valley portion corresponding to the target shift range. The abnormality monitoring unit monitors an abnormality. When a stagnation abnormality is determined in which the engagement member does not reach the target valley portion and stagnates, the drive control unit controls the drive of the actuator so that the engagement member fits into the valley portion on the side where the engagement member is returned from a stagnant position.

A transmission for a machine is disclosed. The transmission may comprise a first torque path for transmission of torque from an input shaft to an output shaft, and a single clutch element along the first torque path. The transmission may further comprise a clutch actuator configured to actuate engagement of the clutch element, and a clutch pressure control (CPC) valve configured to permit a flow of hydraulic fluid to the clutch actuator when in an open position to cause the clutch actuator to actuate engagement of the clutch element. The transmission may further comprise a FMR valve having a failure position obstructing flow of the hydraulic fluid from the CPC valve to the clutch actuator when the CPC valve is in the open position. The FMR valve actuated by pilot pressure from a CPC valve that controls actuation of other clutch elements that are not on the first torque path.

A transmission system for a vehicle comprises a first partial transmission (T1) with a first controllable clutch (C1) and a second partial transmission (T2) with a second controllable clutch (C2) each forming a respective transmission path between an input (ci; ci1, ci2) and a common output (to), the first and the second controllable clutch (C1, C2) having a first and a second actuating means (CA1,CA2) respectively, to control an operational state of said controllable clutches. A controller (CNTR) is provided to control the first and the second actuating means, the controller being configured to selectively assume one of a plurality of control modes. These include amongst others a safety control mode which is selected upon detecting that a value of an acceleration of the vehicle is lower than a negative threshold value.