Abstract: In an internal combustion engine of the crossflow type, a cylinder head is formed therein with an exhaust gas recirculating passage which opens at one end in the inner peripheral surface of the exhaust port, wherein the open end is directed at a predetermined sharp angle with respect to the same inner peripheral surface and in a direction reverse to the direction in which the flow of exhaust gases is introduced into the exhaust port. Further, at least part of the exhaust gas recirculating passage extends in the vicinity of at least one cooling water jacket formed within the cylinder head. Thereby, recirculation of an excessive amount of exhaust gases can be prevented and the temperature of exhaust gas recirculated can be lowered.

Abstract: In the valve mechanism of an internal combustion engine of the overhead camshaft type, a camshaft holder mounted on the cylinder head and supporting rocker shafts thereon has two bearing recesses having a generally semicylindrical shape, formed in a side surface remote from the cylinder head for supporting a pair of rocker shafts received therein, and a lubricating oil passage formed therein and communicating a lubricating oil passage formed in the cylinder head with the hollow interior of one of the rocker shafts. The camshaft holder is further formed therein with two communication passages communicating a peripheral groove formed in a bearing surface opening in a side surface facing the cylinder head for supporting the camshaft, respectively, with two annular gaps defined between two bolt-fitting holes and two bolts extending therethrough to fix the rocker shafts and the camshaft holder to the cylinder head.

Abstract: An internal combustion piston engine has a main combustion chamber and an auxiliary combustion chamber connected by a torch passage. On the suction stroke of the piston lean mixture is drawn into the main combustion chamber and rich mixture is drawn into the auxiliary combustion chamber. A spark plug ignites the mixture in the auxiliary combustion chamber at the end of the compression stroke, causing a torch flame to be projected through the torch passage into the main combustion chamber near its center. A suction conduit, smaller in diameter and total area than the torch passage, extends from a peripheral portion of the main chamber and intersects the torch passage between its ends. Movement of the burning gases through the torch passage aspirates a flow of mixture from the main combustion chamber through the suction conduit into the torch passage.

Abstract: An internal combustion piston engine has a main combustion chamber and an auxiliary combustion chamber connected by a torch passage, which is cylindrical end to end. Lean mixture is supplied to the main combustion chamber and rich mixture is supplied to the auxiliary combustion chamber. A spark plug ignites the mixture in the auxiliary combustion chamber, causing a torch flame to be projected through the torch passage into the main combustion chamber near its center. Suction conduits, smaller in diameter and total area than the torch passage, extend from a peripheral portion of the main chamber and intersect the torch passage between its ends. Movement of the burning gases through the torch passage aspirates a flow of mixture from the main combustion chamber through the suction conduits into the torch passage.