Abstract: A vacuum signal is produced, which is representative of a function of the flow rate of engine taken air and which is employed for directly or indirectly operating a diaphragm unit of an exhaust gas recirculation control valve, by admitting atmospheric air into a vacuum from a vacuum source by employing a solenoid valve in such a manner that the solenoid valve varies the amount of admitted atmospheric air in accordance with the flow rate of engine taken air.

Abstract: An engine equipped with an electronically controlled fuel injection system is provided with an EGR control system which accurately regulates the EGR rate in accordance with a vacuum signal produced at a venturi formed in the intake passageway of the engine, under low and medium load engine operating conditions. However, under high speed and high load engine operating conditions, a part of intake air is bypassed through a bypass passage connecting the upstream and downstream sides of the venturi in order to prevent increase of the flow resistance of the intake air.

Abstract: Disclosed is an automotive multi-cylinder internal combustion engine in which exhaust gases from one or more of the exhaust ports of the engine cylinders are partially recirculated into the mixture induction system of the engine and secondary air is injected into exhaust gases from the remaining exhaust ports under normal operating conditions of the engine. The recirculation of the exhaust gases is interrupted and furthermore secondary air is injected into the exhaust gases from all the engine cylinders under predetermined non-normal operating conditions such as idling and decelerating conditions of the engine.

Abstract: An internal combustion engine of the reciprocating piston type, which is provided with an exhaust gas recirculation circuit to suppress the formation of NOx and has two or three spark plugs for each combustion chamber. There is a substantial overlap of the opening periods of exhaust and intake valves, so that a portion of the combustion gas is left unexhausted. The combustion chamber has a simple shape such as hemisphere, and the spark gaps of the plural spark plugs are arranged distant from each other in each combustion chamber so as to respectively share approximately equally divided portions of each combustion chamber. The number of the spark plugs is two when the volume of the recirculated exhaust gas, including the unexhausted combustion gas, is about 50% at the maximum of the volume of air admitted into the combustion chamber but three when the recirculated exhaust gas amounts to about 60% of the air at the maximum.

Abstract: Two sets of breaker contacts respectively associated with independent ignition systems have two breaker arms with identical configuration, arranged coaxially one above the other to engage a cam at an identical angular position thereof whereby the contacts open and close synchronously.

Abstract: Two spark plugs are disposed in each combustion chamber of an internal combustion engine to effectively ignite the air-fuel mixture which is mixed with a relatively large amount of the exhaust gases which is supplied into the combustion chamber from the exhaust system of the engine. Each spark plug is located so that the electrodes thereof lie at the same height as the center of an intake valve seat in the combustion chamber.

Abstract: Intake and exhaust valves and an intake port of an internal combustion engine are arranged so that strong swirl turbulence of the inducted air-fuel mixture is produced in the combustion chamber. The swirl turbulence improves the combustion of the air-fuel mixture mixed with exhaust gases, initiated by the ignition with two spark plugs disposed in the combustion chamber.

Abstract: Siamesed exhaust ports are formed in an engine cylinder head and contain therein port liners. An exhaust manifold has therein an aftercombustion chamber which is enclosed by a heat insulator and communicates with the siamesed exhaust ports thereby preventing reduction of temperature of the exhaust gases admitted into an exhaust manifold from the engine. Thus, sufficient oxidation of the combustible compounds in the exhaust gases is achieved in the aftercombustion chamber of the exhaust manifold.

Abstract: The valve lift and the valve timing of the intake and exhaust valves of an internal combustion engine are changed in response to an engine operating condition. Furthermore, the intake and exhaust valves are maintained closed during deceleration of the engine.

Abstract: The valve lift and the valve timing of the intake and exhaust valves of an internal combustion engine are changed in response to an engine operating condition. Furthermore, the intake and exhaust valves are maintained closed during deceleration of the engine.

Abstract: An air-fuel mixture shut off means connected to selected branch tubes of an intake manifold of the engine and includes dampers swingably mounted in the selected branch tubes and a controller operable to close the dampers when the engine is decelerated.

Abstract: An air-fuel mixture containing a relatively large amount of recirculated exhaust gases is smoothly and rapidly burned by producing squish turbulence and igniting the mixture with a plurality of spark plugs.

Abstract: A multiple-cylinder spark-ignition internal combustion engine for an automotive vehicle, in which the ratio of the inactive compounds in the mixture gases produced in each combustion chamber to the fuel component in the combustible mixture inducted into the chamber is maintained within a predetermined range and the spark plug for each engine cylinder is arranged so that the flame travel from the spark plug is reduced to a minimum for promoting the combustion reaction to proceed in the least possible time. Improvements are further made in respect of the exhaust gas recirculation rate, the location and measurements of the spark plug, the configurations and measurements of the engine cylinder and the arrangement of the intake and exhaust ports so as to reduce the concentrations of toxic compounds in the exhaust gases without impairing the performance efficiency of the engine.

Abstract: Each combustion chamber of an internal combustion engine is equipped with at least two simultaneously working spark plugs which are arranged distant from each other and located out of a central region of the combustion chamber, and an exhaust recirculation circuit including a flow control valve is arranged to recirculate exhaust gas to a nearly stoichiometric air-fuel mixture to be fed to the engine at a high recirculation rate on the maximum of 12-40% by volume of the quantity of air drawn into the engine.

Abstract: A combustion arrangement which enables combustion with high EGR comprises an ignition means positioned within an area which is disposed in the neighborhood of a location at which the thickness of the combustion chamber is the maximum and adjacent the cylinder axis.

Abstract: A restrictor in an exhaust gas feed conduit to the intake manifold has therein an opening operable to allow the exhaust gases passing through the opening to have a sonic velocity. A valve operates in response to the flow rate of the intake air passing through the carburetor for proportionally controlling the flow rate of the feeding exhaust gases with that of the intake air. The flow rate communicated to the valve has an atmospheric bleed controlled by a solenoid valve energized by a transmission switch.

Abstract: A conduit connecting the intake and exhaust systems of an internal combustion engine is equipped with a control valve for controlling the amount of exhaust gases passing through the conduit. A venturi portion constituting part of a Laval nozzle is provided to a portion of the conduit between the control valve and the intake system of the engine.

Abstract: An exhaust gas recirculation system for an internal combustion engine comprises an exhaust gas flow control valve; a vacuum actuator for operation of the flow control valve; and a control apparatus which provides an output vacuum to be applied to the vacuum actuator which is an amplification of the venturi vacuum.

Abstract: An exhaust gas recirculation system comprises an exhaust gas flow control valve; a vacuum actuator for operation of the flow control valve; and a control apparatus for the vacuum actuator. The control apparatus comprises a vacuum regulator and a vacuum motor for actuating the vacuum regulator in response not only to the venturi vacuum but also to the intake manifold vacuum.

Abstract: An air-pollution preventive arrangement for use with an internal combustion engine for motor vehicles, adapted to reduce the concentrations of noxious compounds such as unburned hydrocarbons and carbonmonoxides contained in the engine exhaust gases. The arrangement comprises a thermal reactor for primarily re-combusting the exhaust gases and a catalytic converter for secondarily recombusting the exhaust gases passed from the thermal reactor so as to oxidize the residual unburned compounds. An air injection unit supplies additional air which is admixed, in a limited proportion, to the exhaust gases entering the thermal reactor to aid in the primary re-combustion of the exhaust gases therein. The noxious unconsumed hydrocarbons and carbon-monoxides are thus converted into innocuous compounds at efficiencies which are far higher than those attained where the thermal reactor or the catalytic converter is employed independently.