Fuel saving system that facilitates vehicle re-starts with the engine off

摘要

A fuel saving system for a vehicle powered by an internal combustion engine and having a hydraulically activated automatic transmission. The system includes a hydraulic pump able to supply pressurized transmission fluid to the automatic transmission, an energy storage device, and at least one motor powered by the energy storage device including a motor that is mechanically connected to the hydraulic pump and a motor that is coupled to the engine. The system also includes a controller that is responsive to one or more operating conditions to turn off the engine when the vehicle is stopped and to use the motor that is mechanically connected to the hydraulic pump so as to activate the pump to supply sufficient power to the transmission to maintain engagement of the transmission in a driving gear. The controller is also responsive to one or more operating conditions to activate the motor that is coupled to the engine so as to restart the engine with the transmission engaged in a driving gear.