Patent ID: 7131411
Filing Date: 2006-11-07
Classification: F01L

Abstract:
1. A method to limit the bleed down of a variable duration hydraulic lifter by utilizing the components of an engine valve train, comprising: (a) providing an engine valve train which includes a valve, (b) providing a cam of a camshaft for use with a non-variable duration lifter, (c) providing a bleed down variable duration hydraulic lifter which is modified to reduce the plunger travel of said lifter riding on or acted upon by said cam, the components of said lifter consisting of an outer cylindrical body and an inner plunger axially slidable within said outer cylindrical body and defining an oil chamber therebetween, said outer cylindrical body defining a seat which defines or supports a lower most position for said plunger, wherein at least one component of said bleed down variable duration hydraulic lifter is modified in dimensional size or positioned so as to reduce the amount of axial movement of said plunger within said outer cylindrical body, (d) providing connecting linkage between said bleed down variable duration hydraulic lifter and said valve, said valve train comprising being of effective dimension such that when said valve is statically seated, said inner plunger is limited to no more than approximately 0.050 inch axial movement within said outer cylindrical body, whereby the bleed down of a variable duration hydraulic lifter is limited by the axial movement of said plunger within said outer cylindrical body when combined with a cam of a camshaft for use with a non-variable duration lifter, and whereby proper rocker arm geometry is maintained without the need for modifications to the valve train connecting linkage.