Abstract: This application discloses an exhaust gas recirculation system in an internal combustion engine. The system comprises:An EGR pipe which interconnects an exhaust pipe and an intake pipe of the engine;An EGR valve mounted on said EGR pipe;An EGR cooler mounted on said EGR pipe upstream of said EGR valve;A by-pass pipe arranged parallel to said EGR cooler;A thermosensor which detects the EGR gas temperature; and,A selection valve arranged at the connection point of said by-pass pipe to said EGR pipe, said selection valve co-operating with said thermosensor so that when the EGR gas temperature is low, the EGR gas passes through said by-pass pipe.

Abstract: Disclosed is a catalyzer heating device of an internal combustion engine. The glow plug is disposed in the catalyzer of the catalytic converter. The glow plug is operated when the temperature of the engine and the temperature of the catalyzer are relatively low so as to increase the temperature of the catalyzer for improving the exhaust gas purifying efficiency in the catalyzer.

Abstract: A combustion chamber structure for an internal combustion engine, which combustion chamber structure includes a main combustion chamber and a separate auxiliary combustion chamber. The main combustion chamber is supplied solely with air by a conventional intake valve. A passage interconnects the main and auxiliary combustion chambers for permitting air to flow into the auxiliary combustion chamber during the compression stroke of the piston. The auxiliary combustion chamber has a fuel-injection nozzle and a spark ignition plug associated therewith. An obstacle, such as a spherical or cylindrical member, is positioned within but spaced from the sidewall of the auxiliary combustion chamber, whereby a circular flow pattern is created within the auxiliary combustion chamber which improves the fuel atomization and the uniformity of the fuel-air mixture.

Abstract: An internal combustion engine utilizing a combustion process of the stratified charge type, and having an auxiliary combustion chamber formed in a cylinder head portion in addition to a main combustion chamber, a passage communicating the auxiliary combustion chamber with the main combustion chamber and being provided with an ignition plug and a fuel injection nozzle for the auxiliary combustion chamber. This passage has a cross-section of a flat envelope, has a predetermined cross-sectional area relative to the transverse cross-sectional area of the piston, is inclined at an acute angle to the upper surface of the piston head, and extends tangentially to the auxiliary combustion chamber. The ignition plug is located upstream of the swirl in the auxiliary combustion chamber in relation to the fuel injection nozzle.