Power plants – Internal combustion engine with treatment or handling of... – By means producing a chemical reaction of a component of the...
Reexamination Certificate
1999-11-23
2001-11-06
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...
C060S304000, C060S305000, C060S306000
Reexamination Certificate
active
06311483
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for feeding secondary air to exhaust gas in an engine, in which an exhaust port for discharging exhaust gas from a combustion chamber and a secondary air feed passage for feeding secondary air to exhaust gas flowing through the exhaust port are provided in a cylinder head of the engine.
2. Description of Related Art
An apparatus of this type has been known, for example, from Japanese Utility Model No. Sho 61-4009. The apparatus disclosed in the above document, however, is problematic. In this apparatus, a secondary air feed passage is provided in a cylinder head in such a manner as to extend substantially in parallel to the axial line of a cylinder bore and a reed valve is mounted in a head cover for covering the cylinder head. To be more specific, the secondary air feed passage is opened to an exhaust port in such a manner as to face toward exhaust gas flowing through the exhaust port, so that exhaust gas is liable to permeate into the secondary air feed passage. This results in the flow resistance in the secondary air feed passage possibly increasing by adhesion of carbon or the like on the inner surface of the secondary air feed passage. Furthermore, since the reed valve is prevented from being eroded by permeation of exhaust gas into the secondary air feed passage, the apparatus disclosed in the above document is configured such that the secondary air feed passage extending in a straight line is made relatively long and correspondingly the reed valve is disposed at a position relatively far from the cylinder head. This results in enlargement of the entire engine.
SUMMARY OF THE INVENTION
In view of the foregoing, the present invention has been made, and an object of the present invention is to provide an apparatus for feeding secondary air to exhaust gas in an engine, which is capable of making a length of a secondary air feed passage as short as possible while preventing the permeation of exhaust gas into the secondary air feed passage as much as possible. This avoids the enlargement of the entire engine when a reed valve is disposed in the engine, since the reed valve is mounted to the cylinder block.
To achieve the above object, according to the present invention, there is provided an apparatus for feeding secondary air to exhaust gas in an engine, in which a cylinder head is connected to a cylinder block in such a manner that a combustion chamber is formed between the cylinder head and a piston slidably fitted in a cylinder bore provided in the cylinder block. An exhaust port for discharging exhaust gas from the combustion chamber is provided in the cylinder head. A secondary air feed passage for feeding secondary air to exhaust gas flowing through the exhaust port is provided in the cylinder head. The secondary air feeding apparatus includes the secondary air passage including a first passage portion extending in a straight line with one end opened to the inner surface of the exhaust port toward the downstream side of exhaust gas in the flowing direction, and a second passage portion continuous with the first passage portion having a straight axial line bent from the axial line of the first passage portion towards the cylinder block side. Furthermore, a reed valve connected to the secondary air feed passage is mounted to the outer surface of the cylinder block.
With this configuration, since one end of the secondary air feed passage is opened to the inner surface of the exhaust port toward the downstream side of exhaust gas in the flowing direction, the secondary air is sucked from the secondary air feed passage into the exhaust port by the flow of exhaust gas in the exhaust port. This prevents the permeation of exhaust gas into the secondary air feed passage as much as possible. Also, the secondary air feed passage is configured such that the second passage portion is in communication with the first passage portion in the direction in which the second passage portion is bent towards the first passage portion. Accordingly, even if exhaust gas permeates into the first passage portion of the secondary air feed passage, the permeation of the exhaust gas into the second passage portion is prevented as much as possible. This makes it possible to shorten the length of the secondary air feed passage. Furthermore, since the reed valve is mounted on the outer surface of the cylinder block, it is possible to avoid the enlargement of the entire engine when disposing the reed valve in the engine.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
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Hori Yoshiaki
Hosono Kenji
Kubota Toshiyuki
Nishi Tohru
Birch, Stewart Kolasch & Birch, LL
Denion Thomas
Honda Giken Kogyo Kabushiki Kaisha
Tran Diem
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