Abstract: Sliding contact-making structures of an internal combustion engine, which comprise (a) a cylinder unit having an inner plating coating containing a dispersoid substance such as a plating coating of Ni-P-SiC or Ni-SiC; and (b) a piston provided with at least one piston ring, fitted into the inside of the cylinder in the axial direction so as to freely slide upon the inside surface thereof, are characterized in that the piston ring has a surface in sliding contact with the inside surface, which surface is covered with a vapor deposition layer such as a physical vapor deposition layer of TiN or CrN, whereby resistance to friction abrasion and seize, and the friction coefficient can be effectively improved.

Abstract: A number of embodiments of inductions and fuel injection systems for internal combustion engines that improve exhaust emission control and fuel economy without adversely effecting the running of the engine under any running condition. This is accomplished by injecting fuel into one of at least two intake passages and providing exhaust gas recirculation into another of the intake passages. A stoichiometric fuel air mixture is introduced and the amount of exhaust gas recirculation is such that a minimum amount of air is inducted into the combustion chamber through the other intake passage when exhaust gas recirculation is being accomplished. Both two and three intake valve systems are disclosed and these use either control valves for controlling the flow through the other intake passages or operate without control valve.