Patent ID: 7644688
Filing Date: 2010-01-12
Classification: F01L,Y10T

Abstract:
1. A valve actuator assembly for an internal combustion engine comprising: a housing; a movable poppet valve; a movable first spool valve; a movable second spool valve having a center biased position and detent feature; a driving channel interconnecting said second spool valve and said poppet valve; an intermediate channel interconnecting said first spool valve and said second spool valve; a first feedback channel interconnecting said second spool valve and said poppet valve; a second feedback channel interconnecting said second spool valve and said poppet valve; an actuator operatively cooperating with said first spool valve to position said first spool valve thereby selectively allowing fluid flow in and out of said second spool valve and said driving channel to position said poppet valve; a first on/off valve in fluid communication with said first feedback channel to selectively exhaust said first feedback channel; and a second on/off valve in fluid communication with said second feedback channel to selectively exhaust said second feedback channel, whereby the first on/off valve and the second on/off valve control motion of the second spool valve; wherein said detent feature includes a second spool valve spring preloaded between a first spring retainer and said housing, and a third spool valve spring preloaded between a second spring retainer and said housing; and wherein the preload of only one of said second and third spool valve springs is applied to said second spool valve when displaced from said center biased position.