A method for operating a hybrid drive assembly for a motor vehicle, which has an internal combustion engine and an electric engine. A separating clutch arranged in drive terms between the internal combustion engine and the electric engine is set to a target clutch torque by at least partially engaging during an attempt to start the internal combustion engine. An actual clutch torque actually transmitted via the separating clutch and a speed of the internal combustion engine are determined during the attempt to start, and if a characteristic value dependent on the actual clutch torque exceeds a threshold value and if an integral of the speed over time continuously falls below a limit value during the attempt to start, the attempt to start is aborted.

Methods and systems are provided for reducing torque pulsations during hybrid engine shutdown and restarts. A valve actuating mechanism may be actuated to operate an engine with a selected valve lift profile during engine restart and shutdown events that is distinct from the valve lift profile applied during cylinder combustion. The selected valve lift profile reduces cylinder pressure during engine shutdown and restarts.

A first electric power generation device configured to produce an accessory voltage according to a first instruction voltage. A second electric power generation device configured to produce the accessory voltage according to a second instruction. An electric control unit is configured to execute crank position stop control for stopping a crank of the engine at a target position when the engine is stopped by controlling the first electric power generation device such that a current is circulated in the first electric power generation device and the rotating electric machine generates braking torque. The electric control unit is configured to execute the crank position stop control in a state in which the second instruction voltage is equal to or higher than the first instruction voltage.

A system and method for modifying the engine pull-up (EPU) logic within a hybrid vehicle based on max motor torque that accounts for the drop or change in available motor torque due to the opening/slipping of a torque converter bypass clutch during engine starts is disclosed. An engine pull-up threshold is determined from max available motor torque at a virtual impeller speed, where the virtual impeller speed is the impeller speed that would result if the torque converter bypass clutch was open/slipping and transferring the same amount of torque.

In a hybrid vehicle control system, when a first traveling mode using torque of an electric motor is switched to a second traveling mode using torque of an engine, a controller performs an engine start control by applying an engagement pressure to a first clutch and by cranking the engine by the electric motor, so as to start the engine. Specifically, the controller obtains a predicted start time and an actual start time by the engine start control, and corrects the engagement pressure so as to decrease the engagement pressure applied to the first clutch at a subsequent time of starting the engine, when the actual start time is shorter than the predicted start time.

A hybrid power train structure for off-road vehicles (ATVs, UTVs and SSVs) uses an internal combustion engine (“ICE”) rotating a crankshaft through a continuously variable transmission (“CVT”) as a primary source of locomotion torque, but also includes a driving/generator motor which, in certain established conditions, can either provide an additional or alternative source of locomotion torque or can harvest electricity from the torque created by the internal combustion engine. The driving/generator motor is an axial flux motor of small size for its relative torque output, which can either be directly coupled to the CVT output shaft or, when additionally used as a starter motor for the ICE in an automatic ICE starting and stopping routine.

In a vehicle control method, when drive force which a second electric motor is requested to output increases in a state where an internal combustion engine is stopped, drive force which the second electric motor outputs by using electric power supplied by a battery is limited to a lower level than maximum drive force determined from electric power which can be supplied by the battery to drive an electric-powered vehicle. Then, the drive force which the second electric motor outputs by using the electric power supplied by the battery is increased over time in a period from when the second electric motor outputs the drive force limited to the lower level to when the internal combustion engine is fired up and a first electric motor starts power generation.

A hybrid power train structure for off-road vehicles (ATVs, UTVs and SSVs) uses an internal combustion engine (“ICE”) rotating a crankshaft through a continuously variable transmission (“CVT”) as a primary source of locomotion torque, but also includes a driving/generator motor which, in certain established conditions, can either provide an additional or alternative source of locomotion torque or can harvest electricity from the torque created by the internal combustion engine. The driving/generator motor is an axial flux motor of small size for its relative torque output, which can either be directly coupled to the CVT output shaft or, when additionally used as a starter motor for the ICE in an automatic ICE starting and stopping routine.

Air conditioning systems and methods for a vehicle having a start-stop engine system. The systems and methods cool the vehicle's passenger cabin when the vehicle's engine and air conditioning compressor are off.

A vehicle propulsion system includes an engine and a first electric machine each configured to selectively provide torque to propel the vehicle. The propulsion system also includes a second electric machine coupled to the engine and configured to start the engine from an inactive state. A high-voltage battery powers both of the first electric machine and the second electric machine over a high-voltage bus. The vehicle further includes a controller programmed to issue a command to start the engine using the second electric machine in response to a threshold acceleration demand following a period of reduced acceleration demand.