Patent ID: 6192845
Filing Date: 2001-02-27
Classification: F01L

Abstract:
A hydraulic lash adjuster for an internal combustion engine, said lash adjuster comprising a body defining a blind first bore therein, and a fluid port in communication with a source of fluid pressure; a plunger assembly slidingly received within said blind first bore, said plunger assembly and said blind first bore cooperating to define a pressure chamber, and a fluid chamber disposed within said plunger assembly; biasing means normally urging said plunger assembly outward of said blind first bore; said plunger assembly including an upper plunger element having a ball plunger element adapted for engagement with an adjacent surface of a valve train component, and a lower plunger element, said blind first bore and said lower plunger element cooperating to define a leakdown clearance providing fluid communication between said pressure chamber and said fluid chamber; said upper plunger element including top, center, and bottom lands cooperating with said blind first bore to define a nominal diametral clearance, said ball plunger element defining a fluid meter passage adapted to communicate fluid to said adjacent surface of a valve train component, said upper plunger element defining a fluid passage providing fluid communication from a region between said center and top lands to said fluid meter passage; characterized by:(a) said top, center, and bottom lands cooperating with said blind first bore to define a reduced diametral clearance, substantially less than said nominal diametral clearance; and(b) said center land defining fluid passage means having a predetermined flow area, said flow area being selected to provide a desired metering flow through said fluid meter passage.