Abstract: A composite cylinder head of an internal-combustion engine includes a bottom wall part to face the combustion chamber and a reinforcement part disposed on the side of the bottom wall part opposite to the combustion chamber and functioning as a back-up reinforcement of the bottom wall part. The two parts of the cylinder head are joined into a single integral structure. The bottom wall part is formed from a metal of higher high-temperature strength and lower thermal conductivity than those of the material of the reinforcement part. This cylinder head makes possible the use of a higher maximum pressure within the cylinder than that in the case of a conventional cylinder head.

Abstract: A gas injection valve of a gas engine includes a valve body having a nozzle chamber with nozzle holes for injecting fuel gas, a first gas passage for introducing fuel gas, and a second gas passage communicable at one end to the first gas passage and at the other end to the nozzle chamber. A first needle valve closes and opens communication between the first and second gas passages. A second needle valve closes and opens communication between the second gas passage and the nozzle chamber. The first and second needle valves are urged in the closing direction thereof. A hydraulic actuator opens the two needle valves. An extreme tip of the first needle valve in closed state is disposed within and exposed to the interior of the second gas passage.

Abstract: A cylinder assembly in an internal-combustion engine having a cylinder liner is provided with a reinforcing ring shrunk fitted around the upper end part of the liner and provided with liquid passages communicating with respective recesses grooved in the outer surface of the upper end part of the liner, thereby forming cooling liquid passageways of a cooling system. This construction affords high strength of the cylinder assembly and remarkably effective cooling performance thereof, which make possible the production of engines of extremely high performance.

Abstract: In an internal-combustion engine, a piston pin of each piston is integrally and rigidly fixed to the small end of a connecting rod. The piston pin is pivotally coupled to the piston by way of a metal bearing interposed therebetween, and is held thus in coupled state by bearing caps respectively clamping the ends of the piston pin against the piston over an interposed metal bearing. The greater part of the piston pin is of a large diameter, and its length is only slightly less than the outer diameter of the piston, whereby a practically maximal bearing area is afforded between the piston and piston pin for withstanding forces transmitted therebetween.

Abstract: A system for detecting abnormalities in a gas engine comprises: a pressure measuring device for measuring the pressure within each engine cylinder to generate corresponding signals; a device for determining from these signals the maximum pressure for every cycle of the engine operation; a comparator circuit for comparing each maximum pressure with reference values of a specific range and, when the maximum pressure is outside of that range, generating a corresponding signal indicating the existence of an abnormality; and an actuator operating in response to this signal to actuate and close a shut-off valve in the fuel gas supply line of the engine, an alarm device being simultaneously activated by this signal.

Abstract: A piston is provided for an internal combustion engine, having a crown portion comprising an upper part and a lower or ring-bearing part which two parts are of different metals welded together. The two metals are chosen to have the same coefficient of expansion but the metal of the upper part of the piston crown is less heat-conductive while that of the ring-bearing part is highly heat-conductive. The piston has a cooling chamber formed in it, part of which chamber is adjacent the upper part of the piston crown while another part of the cooling chamber is adjacent the ring-bearing part.

Abstract: Herein disclosed is an elastic coupling using rubber or an elastomer as an elastic element. The elastic coupling includes an inner metal ring having its radially outer surface radially curvilinearly convexed, an outer metal ring having its radially inner surface radially curvilinearly convexed, and an elastomer ring interposed between the inner and outer metal rings and having its radially inner and outer surfaces correspoindingly radially cirvilinearly concaved as to be fitably secured, respectively, to the outer surface of the inner metal ring and to the inner surface of the outer metal ring. Thus, the modulus of shearing strain of the surface portions of the elastomer ring at the side is smaller than that of an inside portion of the same so as to eliminate any pretension of the surfaces of the elastomer ring.