The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Feb. 20, 2001

Filed:

May. 14, 1999
Applicant:
Inventors:

Noboru Nagumo, Tokyo, JP;

Toshihiro Nagano, Tokyo, JP;

Kentaro Hirota, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F02B 7/502 ;
U.S. Cl.
CPC ...
F02B 7/502 ;
Abstract

When an engine is operated at a low and medium speed range, since the combustion pressure introduced into a pressure chamber of a valve drive unit is relatively small, a control valve is projected toward the cylinder by the biasing force of a spring so as to lower the upper edge of the exhaust port. At the same time, in conjunction with this motion of the control valve, a resonance chamber is opened so as to communicate between the resonance chamber and the exhaust port, thereby the engine power is increased. When the engine is operated at a high speed range, since the combustion pressure is relatively large, the control valve goes away from the cylinder so as to enlarge the exhaust port and at the same time, in conjunction with this motion of the control valve, the resonance chamber is closed, thereby the engine power is increased.


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