Engine start point improvement across gear shifts

Abstract

A control system for determining when to start an internal combustion engine of a parallel hybrid electric vehicle having an electric motor connected to a wheel axle of the vehicle through a transmission of the vehicle includes one or more controllers and is configured to receive a signal indicative of a current wheel torque demand; compare the current wheel torque demand to a torque reference to generate a comparison result, wherein the torque reference is based on a decay-based approximation of an actual maximum electric motor wheel torque capacity across states of the transmission; and output an engine start signal in dependence on the comparison result.

Dependencies are inferred from the claim text.