Method and apparatus for controlling a powertrain system including an engine and electro-mechanical transmission

Method for controlling a powertrain comprising an electro-mechanical transmission, an internal combustion engine and an electric machine, the engine providing an engine input torque to the transmission and the electric machine providing an electric machine input torque to the transmission, the transmission providing an output torque comprising the engine and electric machine input torques, the method comprising:

• operating the engine substantially at wide open throttle;
• monitoring an output torque request;
• transitioning the engine input torque employing an engine control module in response to the monitored output torque request by diluting an air fuel charge within a cylinder of the engine through controlling a valve overlap of an exhaust valve and an intake valve of the cylinder, the valve overlap provided by at least one of
• a modified exhaust valve lift curve that decelerates at a first deceleration rate from a peak exhaust opening to a predetermined exhaust valve opening and then decelerates at a second deceleration rate from the predetermined exhaust valve opening in accordance with an extended low slope lift portion of the modified exhaust valve lift curve for a predetermined exhaust valve closing phase angle duration, wherein a magnitude of the second deceleration rate is less than a magnitude of the first deceleration rate, and
• a modified intake valve lift curve that accelerates at a first acceleration rate from a predetermined intake valve opening in accordance with an extended low slope portion of the modified intake valve lift curve for a predetermined intake valve opening phase angle duration and then accelerates at a second acceleration rate after the predetermined intake valve opening phase angle duration, wherein a magnitude of the first acceleration rate is less than a magnitude of the second acceleration rate;
• and
• during transitioning the engine input torque, controlling the electric machine input torque in response to the output torque request and the engine input torque.

A powertrain system, comprising:

• an electro-mechanical transmission;
• an internal combustion engine providing an engine input torque to the transmission, said engine comprising a throttle device, a combustion chamber, an exhaust valve, an intake valve, an exhaust cam, an intake cam, an exhaust cam phaser adjusting the timing of the exhaust cam, and an intake cam phaser adjusting the timing of the intake cam;
• an electric machine providing an electric machine input torque to the transmission;
• the transmission providing an output torque comprising the engine and electric machine input torques;
• and
• a control module
• operating the throttle device at a substantially wide open position,
• monitoring an output torque request,
• controlling the engine input torque through controlling charge dilution in the combustion chamber by a valve overlap setting, the valve overlap setting provided by at least one of
• the exhaust cam phaser that controls a modified exhaust valve lift curve that decelerates at a first deceleration rate from a peak exhaust opening to a predetermined exhaust valve opening and then decelerates at a second deceleration rate from the predetermined exhaust valve opening in accordance with an extended low slope lift portion of the modified exhaust valve lift curve for a predetermined exhaust valve closing phase angle duration, wherein a magnitude of the second deceleration rate is less than a magnitude of the first deceleration rate, and
• the intake cam phaser that controls a modified intake valve lift curve that accelerates at a first acceleration rate from a predetermined intake valve opening in accordance with an extended low slope portion of the modified intake valve lift curve for a predetermined intake valve opening phase angle duration and then accelerates at a second acceleration rate after the predetermined intake valve opening phase angle duration, wherein a magnitude of the first acceleration rate is less than a magnitude of the second acceleration rate, and
• controlling the electric machine input torque based upon the output torque request and a time-lag difference between the output torque request and the engine input torque.