A method and an apparatus for controlling a mild hybrid electric vehicle are provided. The method includes detecting data for operating the vehicle and determining a target torque of an engine based on the detected data. Additionally, the method includes determining whether an operating condition of a limiting logic of a combustion torque of the engine is satisfied based on a temperature of coolant of the engine and operating the limiting logic when the operating condition of the limiting logic is satisfied. A first available combustion torque of the engine is determined based on a speed of the engine and the temperature of the coolant when the limiting logic is operated and a target torque of a MHSG is determined based on the target torque of the engine and the first available combustion torque of the engine. The MHSG is then operated to generate the target torque of the MHSG.

A limp home mode drive method and system for a hybrid vehicle are provided. The method includes prohibiting an operation of an overdrive brake that is included in a transmission for the hybrid vehicle and is driven by an electric oil pump when the hybrid vehicle is being driven and the electric oil pump is not operated. A speed of the hybrid vehicle is then limited based on a heat value of a rotation driver included in the transmission and a torque of a drive motor driving the transmission is limited based on a temperature of the drive motor. A mechanical oil pump included in the hybrid vehicle is operated to enable limp home driving of the hybrid vehicle.

A power transmission system includes first differential mechanism connected to an engine, and second differential mechanism. The first differential mechanism includes a first rotating element connected to the engine, and second and third rotating elements. The second differential mechanism includes a fourth rotating element connected to second rotating element, fifth rotating element connected to a first electric rotary machine, and sixth rotating element that is an output element of the second differential mechanism. The power transmission system further includes at least one of a first clutch and brake, and a second clutch. The first clutch is configured to releasably couple two of the first, second and third rotating elements to each other. The brake is configured to releasably couple the third rotating element to a stationary element. The second clutch is configured to releasably couple the third rotating element to one of the fifth and sixth rotating elements.

A startup control device includes a vehicle temperature sensor configured to sense a temperature of the vehicle, a vehicle startup controller configured to select the second vehicle startup mode in a low temperature state in which the temperature of the vehicle is equal to or smaller than at least a first temperature judgment value when the request of the startup of the vehicle is sensed, and to select the third vehicle startup mode in an extremely low temperature state in which the temperature of the vehicle is equal to or smaller than a second vehicle temperature judgment value which is smaller than the first temperature judgment value when the request of the startup of the vehicle is sensed.

A transmission includes an input shaft coupled to a prime mover, a countershaft, main shaft, and an output shaft, with gears between the countershaft and the main shaft. A shift actuator selectively couples the input shaft to the main shaft by rotatably coupling gears between the countershaft and the main shaft. The shift actuator is mounted on an exterior wall of a housing including the countershaft and the main shaft. A controller controls the shift actuator utilizing an actuating pulse and an opposing pulse.

In the case where the lockup clutch is in the complete engagement state when a changeover between shift stages is made with the second shift mode selected, an electronic control unit holds the lockup clutch in the complete engagement state. Meanwhile, in the case where the lockup clutch is in the slip engagement state, the electronic control unit holds the lockup clutch in the slip engagement state based on a slip amount of the torque converter, or switches the lockup clutch to the complete engagement state.

A control device for a vehicle includes an electronic control unit. The electronic control unit is configured to set a share ratio of driving force of the first electric motor and the second electric motor. The electronic control unit is configured to set the share ratio of the driving force such that when the temperature of a pinion gear in a planetary gear mechanism is higher than a specified temperature, the share ratio of the driving force of the first electric motor is lower than the share ratio when the temperature is lower than the specified temperature.

A method of selectively controlling a power take-off (PTO) assembly includes positioning a clutch assembly radially between a shaft and a PTO gear, operably controlling the clutch assembly with a controller, and selectively engaging the clutch assembly with the controller. The controller monitors signals received from a plurality of sensors and compares the monitored signals with respective signal thresholds. The clutch assembly is engaged when the compared monitored signals are within the signal thresholds.

A powertrain system including an engine and transmission is described, and includes a temperature sensor disposed to monitor a hydraulic fluid for the transmission. A method for monitoring the temperature sensor includes monitoring engine operation including engine coolant temperature and monitoring a signal output from the temperature sensor. An indicated temperature slope is determined based upon the signal output from the temperature sensor, and a temperature region associated with the engine coolant temperature is determined. Performance of the temperature sensor is evaluated based upon the indicated temperature slope and minimum and maximum temperature slope thresholds that are associated with the temperature region.

With a motor in rotation, 0 is set as each of a d-axis current command and a q-axis current command, and offset learning is carried out. Then, in carrying out offset learning, a transmission is controlled such that a shift stage of the transmission falls within a low vehicle speed-side predetermined shift stage range. Thus, the rotational speed of the motor can be more reliably made high to a certain extent, and offset learning can be carried out. As a result, the accuracy of offset learning can be restrained from decreasing.