Trouble detector system for an intake system of an automotive engine

摘要

An automotive engine has a bypass around a throttle valve and at least one valve provided in the bypass. A plurality of reference pressures for pressures in an intake passage of the engine are stored in a memory so as to be derived in accordance with speed of the engine and opening degree of a throttle valve of the engine. Opening degree detected by a throttle position sensor is corrected with opening degree of the valve in the bypass to produce a corrected opening degree. A reference pressure is derived from the memory in accordance with the engine speed and the corrected opening degree. Pressure in an intake pipe is compared with the reference pressure derived from the memory. An abnormality signal is generated when the intake pipe pressure is higher than the reference pressure.