A transmission unit includes: input shafts; output shafts configured to transmit with a corresponding input shaft via gears; a reverse output gear fitted over one output shaft; a reverse synchronizer; a reverse shaft configured to rotate together with a input shaft and a reverse output gear; a motor power shaft; a first and a second motor gears fitted over the motor power shaft; the second motor gear configured to rotate together with a shift driven gear; and a motor synchronizer. A power transmission system including the transmission unit and a vehicle including the power transmission system are also provided.

A propulsion system includes plural inverters configured to be onboard a vehicle and to convert direct current into an alternating current, and plural motors configured to receive the alternating current from the inverters. The motors also are configured to be operably coupled with axles of the vehicle to rotate the axles. The inverters are configured to be coupled with and control the motors that rotate non-neighboring axles of the axles in the vehicle.

A control device for a hybrid vehicle includes a push-start mode and a motor start mode. The push-start mode transmits a driving force from driving wheels to the engine via a first transmission route at a speed detected by a speed detection means equal to or more than a predetermined speed to start the engine. The motor start mode starts the engine using a driving force of the motor at a speed equal to or less than the predetermined speed as well as in a stopped state. At a speed outside a speed range that either mode is executable when a start command of the engine occurs in driving only using the electric motor as the driving source, a control means performs the driving force reduction control for reducing a driving force transmitted from the electric motor to the driving wheels of the vehicle.

A method of controlling a hybrid vehicle includes commanding a first electric machine to provide a compensating torque. The compensating torque is based on a calculated cylinder pressure. The calculated cylinder pressure is calculated using a dynamic model. The model has an initializing input of engine crank position and real-time inputs of measured speed of the first electric machine and measured speed of the second electric machine.

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 hybrid drivetrain having an internal combustion engine which is designed for a maximum internal combustion engine rotational speed; a dual-clutch arrangement which has a first friction clutch and a second friction clutch with a common input element and in each case one output element; a transmission arrangement which has a first sub-transmission and a second sub-transmission; an electric machine connected to the output element of the second friction clutch via a machine transmission ratio (i.sub.M), in such a way that a purely electric driving mode can be established via the second sub-transmission. The electric machine is designed for a maximum machine rotational speed. The maximum machine rotational speed divided by the machine transmission ratio is greater than the maximum internal combustion engine rotational speed. The output element of the second friction clutch is structurally designed for the maximum machine rotational speed divided by the machine transmission ratio (i.sub.M).

Even when a motor fails in an EV travel mode in which a clutch is disengaged, an amount of hydraulic oil that is supplied to the clutch can be secured by reducing a transmission leaked amount. Accordingly, the clutch can be engaged, and an oil pump can be driven by power of an engine. Thus, an evacuation travel by the engine is allowed when the motor fails in the EV travel mode.

A hydraulic system for a hybrid module which is located between an engine and a transmission includes a parallel arrangement of a mechanical pump and an electric pump. Each pump is constructed and arranged to deliver oil to other portions of the hydraulic system depending on the operational mode. Three operational modes are described including an electric mode, a transition mode, and a cruise mode. Various monitoring and control features are incorporated into the hydraulic system.

A machine having a series electric drivetrain system includes an engine to provide mechanical energy to an electric generator, the electric generator able to convert the mechanical energy received from the engine into electrical energy, the electric generator including an input shaft extending through the electric generator, a rotor to rotate on the input shaft, and the input shaft is able to rotate an input gear, an idler gear, a pump drive gear, and a rotor gear, a motor to receive the electrical energy and to produce a rotational output, a single speed ratio direct drive to transfer the rotational output of the motor to a torque output to deliver to a drive shaft, and power electronics to control the electrical energy between the electric generator and the motor and to regulate the rotational output of the motor.

An overheat prevention method includes an rpm comparison step of comparing an engine revolution per minute (rpm) speed with a preset rpm speed by a controller when requiring an engagement of an engine clutch, a temperature comparison step of comparing a temperature of a transmission clutch with a preset temperature by the controller when it is determined that the engine rpm speed is less than the preset rpm speed at the rpm comparison step, and a serial drive mode control step of releasing the engine clutch and engaging the transmission clutch, and controlling a hybrid starter generator (HSG) to charge a battery using engine power to provide driving power to a motor by the controller when it is determined that the temperature of the transmission clutch is higher than the preset temperature at the temperature comparison step.