Output torque error mitigation for strong hybrid PRNDL neutral operation

• Main Authors: CHIN POH FONG, BOWMAN SHAUN C
• Format: Patent
• Language: English
• Published: 02.09.2014
• Subjects: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE ORDIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; PERFORMING OPERATIONS; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TOTHE CONTROL OF A PARTICULAR SUB-UNIT; TRANSPORTING; VEHICLES IN GENERAL

A powertrain system includes an internal combustion engine, at least one electric machine and an electro-mechanical transmission operative to transmit torque to a driveline. A method for controlling the powertrain system includes enabling neutral operation of the transmission in response to an operator input, activating a first clutch coupled to a first planetary gear set, the first planetary gear set which includes a first element, a second element and a third element. Torque commands are coordinated between the engine and a first electric machine to establish a net zero output torque condition. If a violation of the net zero output torque condition is present, slippage of the first clutch is allowed to dissipate net output torque from reacting with the driveline of the powertrain system.