Abstract: A control method and control system for a hybrid electric vehicle powertrain with a multiple-ratio transmission is disclosed in which engine start events are separated in time from transmission ratio shift events to effect a smooth transition from an electric drive state with the engine off to a drive state in which the engine delivers driving power.

Abstract: A system and method of controlling activation of a power source of a hybrid electric vehicle. The method includes determining a vehicle speed, determining an operating state of a brake system, and controlling activation of the power source based on at least one of the vehicle speed and the operating state of the brake system.

Abstract: A control method and control system for a hybrid electric vehicle powertrain with a multiple-ratio transmission is disclosed in which engine start events are separated in time from transmission ratio shift events to effect a smooth transition from an electric drive state with the engine off to a drive state in which the engine delivers driving power.

Abstract: A method for operating a hybrid vehicle having a primary power generating system and a secondary power generating system coupled via a power transmission assembly for delivery of tractive force for the vehicle. The method includes determining acceleration of input speed to the power transmission assembly when the primary power generating system is deactivated, and inferring activation of the primary power generating system based at least in part on the acceleration of the power transmission assembly.

Abstract: A method for operating a hybrid vehicle having a primary power generating system and a secondary power generating system coupled via a power transmission assembly for delivery of tractive force for the vehicle. The method includes determining acceleration of input speed to the power transmission assembly when the primary power generating system is deactivated, and inferring activation of the primary power generating system based at least in part on the acceleration of the power transmission assembly.

Abstract: A system and method of controlling activation of a power source of a hybrid electric vehicle. The method includes determining a vehicle speed, determining an operating state of a brake system, and controlling activation of the power source based on at least one of the vehicle speed and the operating state of the brake system.

Abstract: A method for controlling activation of a power source of a hybrid electric vehicle. A hybrid electric vehicle has first and second power sources connected to a motor. The motor is connected to a transmission adapted to drive a vehicle wheel. The method includes comparing a vehicle speed value to first and second threshold values. If the vehicle speed value is less than the first threshold value, then the method determines whether a vehicle brake is released. If the vehicle speed value is greater than the first threshold value and less than the second threshold value, the method determines whether additional acceleration is demanded. The power source is activated if additional power is demanded or if the vehicle brake has been released. The power source is deactivated if the brake is engaged or if additional power is not demanded.

Abstract: A method for controlling activation of a power source of a hybrid electric vehicle. A hybrid electric vehicle has first and second power sources connected to a motor. The motor is connected to a transmission adapted to drive a vehicle wheel. The method includes comparing a vehicle speed value to first and second threshold values. If the vehicle speed value is less than the first threshold value, then the method determines whether a vehicle brake is released. If the vehicle speed value is greater than the first threshold value and less than the second threshold value, the method determines whether additional acceleration is demanded. The power source is activated if additional power is demanded or if the vehicle brake has been released. The power source is deactivated if the brake is engaged or if additional power is not demanded.