Abstract: Hydrocarbon and carbon monoxide emission of an internal combustion engine fitted with a non-catalytic thermal exhaust reactor is substantially lowered by operating the engine lean during normal modes of engine operation and switching to rich operation during idle using restricted air injection such that the idle exhaust contains about 2-5 volume percent oxygen.

Abstract: An ignition spark advance system for use with spark ignited internal combustion engines having an exhaust gas recycle system which includes EGR vacuum modulator means connected to and modulating an exhaust gas recycle valve. A conventional first vacuum actuated spark advance unit responsive to manifold vacuum signal cooperates with a second vacuum actuated spark advance unit responsive to EGR vacuum signal to advance the ignition spark. The second vacuum actuated spark advance unit provides additional spark advance during periods of lower intake manifold vacuum caused by exhaust gas recycle when the spark advance due to the first unit decreases.

Abstract: A system for improving the starting characteristics of an internal combustion engine is described. The system effects reduced exhaust emissions, especially for engines having thermal reactor and/or exhaust catalyst components. The system comprises a carburetor having throttle means operatively connected to first control means for simultaneously (1) opening said throttle means to obtain engine speed substantially higher than normal starting speed and (ii) retarding spark advance, on starting said engine, said means acting to maintain said engine speed and spark retard for a predetermined time after starting.

Abstract: A fuel induction system for a spark-ignited multicylinder internal combustion engine including a carburetor, a mixing chamber and an intake manifold. The carburetor includes a primary barrel which connects initially to an inlet in the mixing chamber. An outlet from the mixing chamber connects to the intake manifold. The inlet and outlet are arranged such that the direction of air/fuel mixture flow is reversed in passing through said inlet and outlet thereby providing an improved air/fuel mixture, resulting in lower exhaust hydrocarbon and carbon monoxide emission.

Abstract: An improved internal combustion engine, exhaust gas recirculation (EGR) system is described which features the use of a liquid-cooled heat-exchange device to cool the recirculated exhaust before it is fed into the intake system of said engine. A preferred system uses a condensate trap situated downstream of said heat-exchange device. Use of this system effects further reduction in nitrogen oxides (NO.sub.x) content of the exhaust.

Abstract: An ignition spark advance system for use with spark ignited internal combustion engines having an exhaust gas recycle system which includes EGR vacuum modulator means connected to and modulating an exhaust gas recycle valve. A conventional first vacuum actuated spark advance unit responsive to manifold vacuum signal cooperates with a second vacuum actuated spark advance unit responsive to EGR vacuum signal to advance the ignition spark. The second vacuum actuated spark advance unit provides additional spark advance during periods of lower intake manifold vacuum caused by exhaust gas recycle when the spark advance due to the first unit decreases.

Abstract: An internal combustion engine having a carburetor-type fuel induction system in which the primary carburetor barrel delivers an air/fuel mixture into a container. The air/fuel mixture is conducted from the container into the intake manifold. A liquid trap is provided between the primary barrel and the container to collect liquid gasoline running down the side wall. This trapped liquid is delivered directly to the intake manifold, resulting in improved cold start performance of the engine. The container is preferably heated by means such as exhaust gas, liquid engine coolant or electrical heaters.

Abstract: A fuel induction system for a spark-ignited multicylinder internal combustion gasoline engine in which the primary barrel of the carburetor is connected to an inlet in the top of a container which is fitted through an opening in an exhaust gas conduit such that the lower portion of the container extends into the region of hot exhaust gas. An outlet in the top of the container connects to the engine intake manifold. The system gives improved air/fuel mixing and vaporization and improved cylinder-to-cylinder fuel distribution.

Abstract: A multibarrel, high velocity carburetor comprising at least one primary barrel having a conventional venturi construction and at least one secondary barrel which has a cross-sectional area greater than that of the primary barrel and which has means for varying this cross-sectional area in response to engine demand; and its use in a low exhaust emission, spark ignition internal combustion engine system of the lean reactor type, to effect improved driveability. A preferred carburetor has one primary barrel and two variable secondary barrels. A fuel enrichment device is provided which comprises a vane pivotally mounted in the variable venturi section and adapted to incline inwardly to further restrict the venturi cross-section when intake manifold vacuum drops.

Abstract: A method and apparatus for heating the air-fuel mixture in the intake system or intake manifold of an internal-combustion engine which includes a heat exchanger heated by the exhaust gases out of the engine located between the carburetor of an internal-combustion engine and the engine cylinders. The air-fuel mixture is heated by passing through the heat exchanger and around the heat exchanger ports. The temperature of the heat exchanger can be varied to insure maximum vaporization of the fuel in the air stream.

Abstract: A fuel induction system for a spark-ignited multicylinder internal combustion engine including a carburetor, a mixing chamber and an intake manifold. The carburetor includes a primary barrel which connects initially to an inlet in the mixing chamber. An outlet from the mixing chamber connects to the intake manifold. The inlet and outlet are arranged such that the direction of air/fuel mixture flow is reversed in passing through said inlet and outlet thereby providing an improved air/fuel mixture, resulting in lower exhaust hydrocarbon and carbon monoxide emission.

Abstract: An induction system for a gasoline-fueled four-cycle engine having a carburetor which delivers an air/fuel mixture through a primary venturi to a "hot box" evaporation container located in the engine exhaust stream causing any liquid gasoline to be vaporized. The vaporized air/fuel mixture is then conducted to the intake manifold. In V-type engines the "hot box" is located in the exhaust cross-over. At high load a secondary venturi delivers air/fuel mixture directly to the intake manifold. Fuel distribution in multicylinder engines is thereby improved permitting leaner operation without misfire, resulting in decreased hydrocarbon and carbon monoxide emission.