DIVISIONAL OPERATION CONTROLLING TYPE INTERNAL- COMBUSTION ENGINE

PURPOSE:To prevent occurrence of engine stop, by providing a flame detector in each of the combustion chambers of inoperative cylinders, and stopping supply of fuel to the inoperative cylinders in case that ignition and combustion are not caused in the inoperative cylinders at the time of high-load operation of an engine. CONSTITUTION:In an internal-combustion engine consisting of inoperative cylinders 2b, 2c and operative cylinders 2a, 2d, an optical fiber 26 is inserted into each of ignition plugs of the inoperative cylinders 2b, 2c so that flame produced by combustion can be detected by respective light detecting circuits 27 via the optical fibers 26. Outputs of these light detecting circuits 27 are furnished to an electronic control unit 10 and judgement is made whether combustion is started or not in the second and the third cylinders 2b, 2c. In case that judgement is made that combustion is not started in the inoperative cylinders 2b, 2c at the time of high-load operation of the engine when all of the cylinders are to be operated, injection of fuel from fuel injection valves 11b, 11c for the inoperative cylinders is stopped, and operation of intake and exhaust valves of the inoperative cylinders is stopped.