Secondary air injection

About: Secondary air injection is a research topic. Over the lifetime, 11452 publications have been published within this topic receiving 112147 citations.

Effects of Air Intake Pressure on the Engine Performance, Fuel Economy and Exhaust Emissions of A Small Gasoline Engine

Abstract: The study presents the engine performance, fuel economy and exhaust emissions at variations of air intake pressure. In carburetor system, the air intake pressure is influenced by the degree of opening throttle plate and venturi effect which draw the fuel to the combustion chamber. The experimental work is carried out at variations of engine speed and load using a single cylinder four stroke gasoline engine attached with a dynamometer. The measured exhaust emissions compositions are used to determine the mode of combustion. The results show that the standard air intake system resulted in rich combustion which then led to incomplete combustion which is caused by less availability of air for the combustion process. Eliminating the air filter reduces the air flow restriction in the air intake system resulted in better combustion and less unburned components due to higher air availability. Higher air intake pressure is better in increasing the efficiency of combustion within a limited time to improve fuel economy, power output and exhaust emissions. Better combustion also leads to the reduced unburned components such as carbon (C), hydrogen (H2), carbon monoxide (CO) and hydroxide (OH) that resulted in cleaner emissions.

Closely coupled exhaust catalyst system and engine strategy associated therewith

Abstract: A catalytic converter having a first highly loaded palladium or trimetal catalytic element containing palladium of relatively large particle size closely coupled to the engine exhaust manifold, followed by one or more second catalytic elements having high oxygen storage capacity to provide protection against warmed-up engine emissions break through, is efficient in reducing cold-start emissions through early catalyst light-off. The catalytic converter is advantageously used in conjunction with an engine strategy employing oscillative spark retard during warm up to further reduce catalyst light-off and transient spark advance dampening to eliminate spiking of HC and CO during engine transients. When employed in conjunction with secondary air injection, the engine EEC is programmed to delay air injection for a period following cold-start sufficient to assure that catalyst light-off is rapidly attained.

Internal combustion engine with pressure boosted exhaust gas recirculation

Abstract: An exhaust gas recirculating system for a turbocharged diesel engine utilizes an electrically driven compression pump to boost exhaust gas pressure before return to the engine induction system. Exhaust gas is drawn from the exhaust system or stack some distance removed and downstream from the outlet from the exhaust turbine, compressed to overcome the intake manifold boost pressure, and returned to the intake system along an extended pipe to cool the gas. The compressor is energized from the vehicle battery during periods of demand for peak pressure demand on the engine thereby recycling recaptured energy from the battery to boost engine output. Exhaust turbine performance during periods of peak loading is also improved.

Exhaust manifold, for internal combustion engine, for improving durability of oxygen sensor at merging portion of exhaust manifold

Abstract: An exhaust manifold comprising a plurality of exhaust pipes and a merging portion applies exhaust gas from each cylinder uniformly to an oxygen sensor in a merging portion at low speed thereby improving the durability of the oxygen sensor. A downstream forward end of each exhaust pipe of the exhaust manifold, when connected to an inlet wall of a merging case having the oxygen sensor mounted on a side thereof, is formed in the shape of a bell mouth for leading the exhaust gas to the oxygen sensor. Each exhaust pipe is fixedly welded to the merging case at a position upstream of the forward end of the bell mouth. An angle formed by lines perpendicular to tangential lines at starting and ending points of a curved portion of the bell mouth at the forward end of the exhaust pipe is set in the range of 45° to 75°. As a result, the bell mouth spreads over the whole interior of the merging case and reduces a flow rate of the exhaust gas, and part of the exhaust gas flows toward the oxygen sensor. The oxygen sensor is thus more evenly exposed to the exhaust gas and has increased durability.