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.
Patent No.:
Date of Patent:
Sep. 24, 1996
Filed:
Jun. 07, 1995
Susumu Ariga, San Antonio, TX (US);
Jongmin Lee, San Antonio, TX (US);
Southwest Research Institute, San Antonio, TX (US);
Abstract
A valve system for use in internal combustion engines includes a means for controllably varying the preload force imposed on a valve spring in correlation with engine speed. At low engine speeds the preload force is maintained at a minimal level whereby the normal load at the cam/follower interface is maintained at a minimal value. At higher engine speeds, the preload force on the valve spring is selectively increased to assure positive closure of the valve head. The increased preload forces are imposed by extending a hydraulically actuated, moveable spring seating surface whereby the installed length of the spring is shortened. The hydraulic actuating fluid is continuously circulated through inlet and outlet ports, communicating with an expandable chamber associated with the moveable seating surface, during low engine speed operation to abate the problem of temperature rise in static fluid systems.