Abstract: An intake valve apparatus for an air pump having a cylinder with a cylinder iner, a piston positioned within the cylinder liner, a cylinder head and an intake valve. The intake valve comprises an upper annular valve plate having a reed extending inwardly therein and a lower seat plate having an opening facing the reed, the valve plate and seat plate being held between mating surfaces of the cylinder liner and the cylinder head and wherein the reed is positioned for movement in the seat place.

Abstract: An air pump apparatus having a cylinder extending from a pump casing. The cylinder comprises a cylinder liner positioned within the walls of the cylinder and a piston is mounted for reciprocating movement within the cylinder liner. The pump chamber is formed between the front of the piston and the front portion of the cylinder wherein an annular gap is formed between the piston and the inner wall of the cylinder liner, wherein the piston has a plurality of annular grooves formed on the outer circumferential surface thereof, the annular gap and annular grooves forming a labyrinth path extending from the pump chamber.

Abstract: A secondary air introducing device for an engine including a cylinder, an associated piston, and a secondary air introducing hole formed in a side wall of the cylinder in such a manner that said hole is located near the bottom dead center of the piston and is opened and closed by the piston. The secondary air introducing hole is made to communicates through inlet passages with the atmosphere, so that the external air is introduced into the cylinder through the secondary air introducing hole by a negative pressure which is produced in the cylinder at the end of a suction stroke of said engine, and a control valve means opened and closed according to variations in load of the engine is provided in the inlet passages, thus controlling an amount of air introduced therein.

Abstract: A sealing structure of a rotary valve in an internal combustion engine in which a recess is formed either at an opening portion of a rotary valve proper or at an opening portion of a combustion chamber in a housing and in which a seal member slidably fitted in the recess is resiliently pushed against the opposing part by means of a spring member. An annular resilient member is interposed between the lower surface of the seal member and the opposing bottom surface of the recess in such a manner that the two ends of the resilient member are respectively in contact with the surfaces of the seal member and the recess. Thereby, the contact pressure at the ends of the resilient member is increased by utilizing the gas pressure in the combustion chamber. Further, the pushing force of the seal member against the opposing part is increased, so as to enhance sealing efficiency.

Abstract: A secondary air introducing apparatus for an internal combustion engine comprising a secondary air introducing opening in the sidewall of the cylinder near the position of lower dead point of a piston of the engine. The opening is opened and closed by the piston. A secondary air supply source is interconnected with the opening by an introducing passage. The introducing passage is formed to be an upwardly directed passage extending only upwards from the opening.

Abstract: An apparatus for liquid supply in an internal combustion engine having a liquid chamber containing a liquid such as fuel, lubrication oil or the like and located at one side of an intake passage of the internal combustion engine, which liquid chamber is in communication with the intake passage through a delivery passage having a metering throttle interposed therein; and a heating means provided proximately to the throttle portion of the delivery passage.

Abstract: A rotary valve in an internal combustion engine in which the rotary valve proper is formed so as to be hollow and cylindrical and arranged in such a manner that its inner space forms a portion of an intake passage and a portion of an exhaust passage, which portions are separated from each other. In this manner, the valve proper, exhaust passage, and a housing are effectively cooled, and sealing for the rotary valve proper is made effectively and positively.

Abstract: A silencer for an internal combustion engine includes a main silencer having an axially movable tubular member located therein which is movable from a first position in which it constitutes an extension of an inlet to the main silencer and a second position in which it is spaced from the inlet for exhaust gases entering the silencer, thus permitting the exhaust gases to flow directly into the main silencer.

Abstract: An apparatus and method for minimizing the extent of lateral projection of left and right banks of carburetors for a multi-cylinder engine of a motorcyle for accommodating the legs of an operator in which the carburetors are supported rearwards of the engine on a frame beneath a seat for a rider, the carburetors being arranged on opposite sides of the longitudinal axis of symmetry along respective lines which are inclined rearwardly toward the front to form an inverse V-shaped arrangement. The outermost carburetors have lateral bounding planes which are inclined inwardly towards the rear within which a tapered casing of an air cleaner is accommdated. The length of air passages extending from the air cleaner to the inlet ports of the cylinders via the carburetors are equalized for all the cylinders.

Abstract: An auxiliary intake passage system for internal combustion engines having a main carburetor delivering a lean mixture to main combustion chambers through a main intake passage, and an auxiliary carburetor delivering a rich mixture to auxiliary combustion chamber through an auxiliary intake passage. The auxiliary intake passage system is comprised of an induction passage leading from the auxiliary carburetor to an auxiliary intake distribution chamber. A plurality of branch passages extend laterally from said auxiliary intake distribution chamber and lead to the auxiliary combustion chambers. The induction passage comprises a first portion of substantially uniform cross-sectional area connected to a second portion which is tapered and so formed that the internal wall of the tapered section is outside the axial projection of the internal wall of the first portion, thus minimizing resistance to fluid flow and improving fuel distribution and homogenation to each combustion chamber.

Abstract: An internal combustion engine has a main combustion chamber and an auxiliary combustion chamber associated with each piston and connected by a torch opening. A lean mixture is supplied to the main combustion chamber and a rich mixture is supplied to the auxiliary combustion chamber. After compression, ignition of the mixture in the auxiliary combustion chamber projects a flame through the torch opening to burn the lean mixture in the main combustion chamber. In order to prevent an over-rich mixture developing in the auxiliary combustion chamber upon rapid acceleration of the engine, correction devices and systems are employed to reduce the ratio of air intakes or to supply secondary air during such rapid acceleration. Such correction systems and devices may be rendered inoperative during initial startup of the engine.

Abstract: An arrangement for deriving intake negative pressure from an internal-combustion engine, comprising a carburetor in the latter, with an intake for an air -- fuel mixture, a throttle valve therein for regulating the mixture, and at least one longitudinal passage therein for guiding the mixture toward the engine; an intake passage leading from the carburetor to the engine; which latter also has an exhaust passage leading therefrom; wherein the throttle valve has a shaft substantially transversally disposed in one of the passages of the carburetor, the latter being fitted with a discharge opening in a side wall of the intake passage to derive negative passage from the carburetor for regulating and controlling the engine operation; the discharge opening being provided in the flow of the mixture, in an area that is directed downstream from the throttle-valve shaft; whereby to avoid accumulation and discharge of condensed fuel from the carburetor to the discharge opening.

Abstract: A three-valve prechamber internal combustion engine is provided with a conduit through which atmospheric air may be drawn into the intake passage leading to the prechamber. A solenoid valve in the conduit is opened during deceleration of the engine to lean-out any over-rich mixture and to remove any fuel droplets clinging to the walls of the auxiliary intake passage, thus preventing the temporary formation of an over-rich mixture which is not ignited by the spark plug. Such an over-rich mixture when exhausted into the exhaust passage contacts the hot portions thereof to be explosively ignited to produce the undesirable afterburning phenomenon.

Abstract: A three-valve stratified-charge internal combustion piston engine has an auxiliary combustion chamber connected to each main combustion chamber through a torch nozzle. A rich mixture is supplied to the auxiliary chamber and a lean mixture is supplied to the main chamber. A portion of the exhaust gases from the main chamber is recirculated through a control valve to mix with the rich mixture supplied to the auxiliary chamber. For loaded conditions of the engine, additional exhaust gases from the main chamber are recirculated through a control valve to mix with the lean mixture supplied to the main chamber. The control valves are automatically operated by means responsive to engine operating conditions.