Engine control system using a cylinder pressure sensor

Individual cylinder combustion control systems using a cylinder pressure sensor have a system already been introduced to realise a system, highly tolerant of the variability of engine components, fuel quality and environmental conditions. The paper deals with such an application of a cylinder pressure sensor to air/fuel ratio control, which is to control air/fuel ratio to the lean limit of engine stability. To detect the engine stability limit, a statistical signal processing method was applied to the detected peak pressure crank angle position theta _pmax. By using this method, this system needs only relative cylinder pressure value to detect theta _pmax, hence a practical piezoelectric type washer transducer was good enough for this application.