Controller for hybrid vehicle

A controller for a hybrid vehicle,

• the vehicle including
• an engine,
• an electric motor,
• a generator for generating electric power by power of the engine, and
• a battery for storing electric power generated by the electric motor or the generator and supplying the electric power to the electric motor,
• the vehicle being able to run in
• an EV drive mode in which the electric motor is driven by electric power of the battery only and
• a series drive mode in which the electric motor is driven by electric power generated by the generator using power of the engine,
• the controller including
• a demanded driving force calculation unit for calculating a demanded driving force for the electric motor based on vehicle speed and accelerator pedal opening,
• a demanded electric power calculation unit for calculating a demanded electric power based on the demanded driving force and a revolution speed of the electric motor,
• an available uppermost outputting value setting unit for setting an available uppermost outputting value for the battery based on the conditions (SOC+temperature) of the battery, and
• a degree-of-start-demand calculation unit for calculating a degree of start demand for the engine based on the conditions (SOC+temperature) of the battery, the demanded electric power and the accelerator pedal opening,
• an engine starting determination unit for determining on the starting of the engine based on the degree of start demand,
• wherein the engine starting determination unit starts the engine so that the vehicle runs in the series drive mode, when an integral value obtained by integrating the degree of start demand surpasses a predetermined value.