Gm Global Technolgoy Operations, Inc.

Gary Edwin Johnston

Jeffrey M Polidan

Matthew J Roelle

Martin L Hall

Daniel H Hooker

William R Aro

Kevin E Person

John E Jubenville

A diagnostic system according to the present invention diagnoses system failure of a secondary air injection system. The secondary air injection system includes a pump that provides air to an exhaust system via a conduit and a valve that controls the flow of air through the conduit. A pressure sensor measures pressure in the conduit. A controller predicts pressure in the conduit during first, second and third operational phases of the secondary air injection system. The controller compares the measured pressure to the predicted pressure to evaluate operation of the secondary air injection system. During the first phase, the secondary air injection system is used to reduce vehicle emissions. During the second phase, the valve is shut while the pump is on. During the third phase, the pump is turned off while the valve is closed.

Secondary air injection diagnostic system using pressure feedback

A secondary air injection system for reducing the hydrocarbon emissions of an internal combustion engine that is provided with an air pump supplying air to the exhaust manifold of the engine through a check valve assembly and an elastomeric hose characterized in that a baffle in the shape of a helix is located internally within the hose so as to cause the exhaust pressure waves from the engine and passing beyond the check valve assembly to impinge upon the solid compound surface of the baffle and be divided and diffused as they progress along spiraling paths so as to prevent objectionable noises being generated in the hose by the pressure waves.

Secondary air injection system for an internal combustion engine

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Highland, MI, United States of America

Gary Edwin Johnston