System and method for hybrid vehicle engine starts

A method for controlling a powertrain of a hybrid vehicle comprising:

• detecting an accelerator pedal tip-in between 50% and 100% of accelerator pedal tip-in via a pedal sensor;
• responsive to the detection, accessing a torque converter model, by a controller in communication with the pedal sensor, to obtain a predicted impeller speed based on a history of previous accelerator pedal tip-in applications and corresponding to the accelerator tip-in;
• and
• outputting an engine command speed to an engine, by the controller, equal to or greater than the predicted impeller speed to generate a torque output from the engine to a set of wheels.

A powertrain of a hybrid vehicle comprising:

• a motor/generator (M/G) operably coupled to a driveline;
• an engine;
• a disconnect clutch between the M/G and the engine to selectively connect the engine to the driveline;
• a transmission to control a power output to a set of wheels;
• a final drive in communication with the transmission to direct operation of the set of wheels;
• a torque converter including an impeller and located between the M/G and the transmission;
• and
• a controller programmed to monitor tip-in applications to an accelerator pedal in communication with the engine and M/G, and to increase engine speed to a predetermined speed based on a torque converter impeller speed obtained from a torque converter model and reflective of the accelerator tip-in and corresponding to the accelerator tip-in equating to a wheel torque output from the torque converter resulting in saturation.