Power plants – Internal combustion engine with treatment or handling of... – By means producing a chemical reaction of a component of the...
Utility Patent
1999-03-29
2001-01-02
Denion, Thomas (Department: 3748)
Power plants
Internal combustion engine with treatment or handling of...
By means producing a chemical reaction of a component of the...
C060S289000, C060S307000, C060S293000, C181S277000, C181S278000, C181S279000, C123S456000
Utility Patent
active
06167699
ABSTRACT:
TECHNICAL FIELD
This invention concerns air injection systems and more particularly is directed to a secondary air injection system for supplying air into the manifold of an internal combustion system that has a noise attenuating device for preventing objectionable noises from being created by pressure waves as they pass through the elastomeric hoses of the system.
BACKGROUND OF THE INVENTION
In order to meet the exhaust engine emission regulations promulgated by the state of California for trucks, certain truck manufacturers are using an secondary air injection system which supplies air to the exhaust manifold of the internal combustion engine to facilitate the combustion of hydrocarbons in the exhaust gases being treated by the catalytic converter. Typically, the secondary air injection system includes air conduits that take the form of metallic pipes positioned adjacent the exhaust manifold that lead to and are connected to rubber hoses that snake around the engine compartment for connection with the air pump. It has been found that secondary air injection systems of this type can experience objectionable noise at certain RPM and load conditions unless provided with a noise attenuating device in the rubber hoses. The root cause of the noise is an exhaust pressure wave that migrates past the check valve into the rubber hose plumbing. One truck manufacturer utilizes an in-line external resonator close to the system's check valves in each leg of the rubber hoses to eliminate the objectionable noise. Although the external resonators will eliminate the objectionable noise, it has been found that the use of such resonators for this purpose requires additional underhood packaging real estate and results in an increased system cost and complexity.
SUMMARY OF THE INVENTION
The present invention solves the problem of packaging, cost and complexity by providing a baffle in the form of a twisted stainless steel rectangular member that is inserted into each leg of the hose plumbing and positioned adjacent each check valve of the secondary air injection system. The twisted sheet metal baffle serves to diffuse the exhaust pressure wave emitted by the check valve and thus eliminates the objectionable noise.
Accordingly, an object of the present invention is to provide a new and improved air injection system for supplying air to the exhaust manifold of an internal combustion engine so as to facilitate combustion of hydrocarbons in the exhaust gases being treated by the catalytic converter and that includes an internal baffle in one or more legs of the hose plumbing for attenuating noise created by engine exhaust pressure waves.
Another object of the present invention is to provide a new and improved noise attenuating device that can be readily inserted into the hoses of a low emission secondary air injection system for an internal combustion engine and serves to eliminate objectionable noises caused by exhaust pressure waves moving through the hoses of the system.
A further object of the present invention is to provide a new and improved 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 an elastomeric hose having a helix type baffle located internally within the hose so as to cause the exhaust pressure waves to impinge upon the solid compound surface of the baffle and be split in two as they progress along two spiraling paths to prevent objectionable noises being generated by the pressure waves.
A still further object of the present invention is to provide a new and improved secondary air injection system for providing air into the exhaust manifold of an internal combustion engine so as to increase the combustion of hydrocarbons in the exhaust gases being treated by a catalytic converter characterized in that a rectangular sheet of metal is twisted along its longitudinal center axis one end relative to the other at least one hundred eighty degrees and is positioned with an interference fit in each hose of the system adjacent each check valve for diffusing pressure waves as they pass through the hose to thereby prevent objectionable noises.
Stated broadly, the above and other objects are realized in accordance with the present invention by a secondary air injection system having an air pump and including a metallic pipe connected at one end to and extending along the exhaust manifold of an internal combustion engine. A check valve assembly is connected to the other end of the metallic pipe for allowing air to flow through the metallic pipe into the exhaust manifold so as to facilitate the combustion of hydrocarbons in the exhaust gases to be treated by a catalytic converter. A hose made of an elastomeric material is connected at one end to the air pump and is connected at the other end to the check valve assembly and at least one noise attenuating device is located in the hose for causing the pressure waves generated by the engine and propagated through the metallic pipe and the check valve assembly to be split in two and move along two spiraling paths so as to cause the pressure waves to be diffused whereby objectionable noises are prevented from being created by said pressure waves as they pass through the remainder of the hose.
REFERENCES:
patent: 2482754 (1949-09-01), Flint
patent: 3924883 (1975-12-01), Frank
patent: 4266421 (1981-05-01), McDougal
patent: 4373354 (1983-02-01), Sawyer
patent: 4996962 (1991-03-01), Usui
patent: 10131819 (1996-10-01), None
Aro William R.
Johnston Gary Edwin
Jubenville John E.
Denion Thomas
General Motors Corporation
Simon Anthony Luke
Trieu Thai-Ba
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