Engine with variable valve overlap

  • US 4,054,109 A
  • Filed: 03/31/1976
  • Issued: 10/18/1977
  • Est. Priority Date: 03/31/1976
  • Status: Expired due to Term
First Claim
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1. An internal combustion engine of the type having a combustion chamber, a reciprocating valve controlling the passage of gases through an opening communicating with said combustion chamber, a camshaft having a valve actuating cam and means interconnecting said cam with said valve for actuating said valve in timed relation with engine operation, wherein the improvement comprises a yieldable load carrying member in said interconnecting means, said member having an internal chamber that is contracted upon yielding of said member and is adapted to receive a charge of hydraulic fluid which, when retained in said chamber, prevents further yielding of said member and permits the transmission of valve opening loads therethrough, and timing valve means connecting with said chamber and including a pressure responsive valve closure element, said valve closure element being biased open to permit the escape of fluid from said chamber and allow yielding of said load carrying member during initial actuating movement of the valve actuating cam, and being responsive solely to the reaching of a closing differential pressure across said element caused by fluid flow out of said chamber and sufficient to close said chamber, said valve closure element then being maintained closed by fluid pressure in the chamber so as to prevent the further escape of fluid until the fluid pressure is relieved by termination of the reciprocating valve closing motion, said valve opening bias and closing differential pressure being selected to correspond with the dimensional and operating conditions of the engine valve mechanism to provide substantial variation in the timing of said reciprocating valve opening and closing points as a function of engine speed.

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