KNOCKING INDEX VALUE CALCULATION DEVICE AND CALCULATION METHOD THEREOF, TO CALCULATE KNOCKING INDEX VALUE VIA INNER PRESSURE OF CYLINDER AND UNBURNED GAS TEMPERATURE

摘要

PURPOSE: A knocking index value calculation device and a calculation method thereof are provided to reduce the number of matching steps in an ignition time control device and to reduce calculation load of a control system. CONSTITUTION: A knocking index value calculation device of a spark ignition-type engine includes a controller(31). The controller decides an operation condition of the engine, estimates the inner pressure of a cylinder in a reference crank angle set to a crank position after a compression top dead point on the basis of the operation condition; estimates the temperature of unburned gas in the cylinder in the reference crank angle on the basis of the operation condition; and calculates a knocking index value via the inner pressure of the cylinder and the temperature of the unburned gas.