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For better power output and fuel economy of a four stroke cycle ignition engine, the ignition timing should preferably be set to the minimum spark advance for best torque (MBT). It is found that when the ignition timing is set MBT, the crank angle of the maximum combustion pressure (θpmax) usually lies between 12 and 14 deg after top dead center (ATDC) regardless of any engine specifications or operating factors. Therefore, the ignition timing can be controlled to be MBT by using the θpmax. This paper describes the relationship between the θpmax and MBT by both experimental results and numerical calculations, and MBT control system utilizing θpmax. And the test results by using this system are also described.