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:
Jul. 06, 1976
Filed:
Sep. 23, 1974
William G Brown, Burbank, CA (US);
Other;
Abstract
A hydraulic valve lifter for a reciprocating internal combustion engine has a displaceable plunger within a body for coupling a cam lobe with a push rod in a valve train. The cam lobe acts on the base of the body. A cavity within the plunger receives oil from the engine's oil supply and delivers oil through a check valve to a second cavity outside the plunger and within the body. Oil in the second cavity force couples the plunger and the cam lobe. The volume of oil in the second cavity determines the position of the plunger. A controlled leak path from the second cavity and through the base of the body allows oil to leave the second cavity at a controlled rate. Leakage at low engine speeds prevents complete lift of the plunger, and valve overlap and lift are reduced over that which occurs at full lift. At higher engine speeds, the flow of oil into the second cavity exceeds the flow of oil out through the leak path to lift the plunger and increase exhaust and intake valve overlap and valve lift, and valve duration. (Valve duration is defined as the time, usually expressed in crankshaft degrees, the valves are open.) At all engine speeds the leakage lubricates the surfaces of the body and the cam lobe which contact each other.