Abstract: A compact dual ignition push rod actuated overhead valve internal combustion engine having in a preferred embodiment a 4 cylinder V-type arrangement of 60.degree. bank angle provided with part-spherical combustion chambers having diagonally placed intake and exhaust ports controlled by valves actuated through push rods from a central camshaft and having dual spark plugs with diagonally placed gaps angularly alternating with the ports. The spark plugs extend from the combustion chambers through adjacent outer side and end walls of the cylinder head while the valve actuating push rods pass through openings between the combustion chamber and the cylinder head inner side wall in a compact arrangement for an engine having dual ignition fast burn combustion chambers.

Abstract: An ignition system of an internal combustion engine comprising a metallic plate inserted between the cylinder block and the cylinder head. The metallic plate has an opening, upon the inner peripheral wall of which is mounted a plurality of T-shaped electrodes. Each of the T-shaped electrodes comprises an electrode piece and a conductive bar member connected to the electrode piece. The conductive bar member is surrounded by a tubular insulating member. The tubular insulating member is inserted into bores formed in the metallic plate for forming a condensor between the conductive bar member and the metallic plate. The electrode pieces are arranged in series for forming spark gaps between adjacent electrode pieces, and a high voltage is applied across the electrode pieces.

Abstract: An improved ignition arrangement for internal combustion engines includes, besides an ignition plug normally employed, another ignition plug provided on a guide surface confronting an exhaust port side of a guide wall for prevention of knocking by properly determining ignition time, with a simultaneous improvement of combustibility.

Abstract: A spark-ignition internal combustion engine having a combustion chamber, comprises intake and exhaust valves disposed on a cylinder head wall surface and positioned generally symmetrical with each other with respect to the center axis of the bore of an engine cylinder, at least first and second squish areas which are located respectively in first and second sections of the combustion chamber which sections are defined by dividing the combustion chamber into two by a first vertical plane containing the centers of the intake and exhaust valves, and a spark plug whose tip section is disposed on the cylinder head wall surface and positioned in said first section of the combustion chamber thereby enabling use of high compression ratio without causing engine knock.

Abstract: A combustion chamber of an internal combustion engine has the form of a B-shaped chamber which consists of two spheroidal or spherical contiguous chambers which form an inwardly extending projection against which the air and fuel mixture impinges so as to be divided into two swirl flows which sweep residual burned gases of the previous cycle in the combustion chamber, thereby preventing knocking in the operation of the engine to improve the fuel consumption, driving performance and output of the engine.

Abstract: An internal combustion engine having an ignition chamber communicating with a main combustion chamber via at least one transfer channel, with the ignition chamber forming a closed circular cylinder and its cylindrical wall being protected by an annular thermal pipe from too-rapid cooling and from overheating. In the wall of the ignition chamber, partial electrodes disposed in an insulated manner are provided which are electrically connectable via spark gaps with each other and with the ignition voltage supply line. As a result, ignition occurs near the wall in an area at an elevated temperature level and, in particular, in the immediate vicinity of the entry point of the fresh fuel-air mixture via the overflow channel so that, as a result, the flammability is maintained with increased leaning of the fuel-air mixture.

Abstract: In the ignition system of the internal combustion engine, a preignition control circuit is further provided. The preignition control circuit includes a high voltage generator which supplies a high voltage to the spark plug to produce a preignition spark between the electrodes of the spark plug. The preignition spark is timed to appear as the engine nearly concludes its suction stroke so that radicals are produced from the air-fuel mixture around the electrodes thereby to ensure reliable ignition and complete burning of the air-fuel mixture.

Abstract: A dual spark plug ignition engine with an EGR system is provided with an ignition system which is arranged to achieve single spark plug ignition by sensing a considerably low intake vacuum which represents high power output engine operating range. The engine is further provided with an engine starting sensing switch to cause the ignition system to carry out dual spark plug ignition during engine starting although the intake vacuum is considerably low as at the high power output engine operating range.

Abstract: A spark plug is located in a combustion chamber so as to decrease the combustion time of the charge inducted into the combustion chamber. The charge is formed, before inducted into the combustion chamber, by mixing an air-fuel mixture and substantially inert gas such as exhaust gas so that the weight ratio of the fuel combusted in the combustion chamber and the substantially inert gas falls within the range from 1:13.5 to 1:18.5 during normal engine operation.