Patent ID: 7044433
Filing Date: 2006-05-16
Classification: F01L

Abstract:
1. A valve spring mechanism for a poppet valve ( 101 ) that is capable of use on an internal combustion engine which comprises a valve head ( 102 ) and a valve stem ( 104 ), the mechanism comprising: a piston ( 109 ) and cylinder ( 108 ) arrangement in which the cylinder ( 108 ) surrounds a portion of the valve stem ( 104 ),the piston ( 109 ) is slidingly and sealingly mounted on the valve stem ( 104 ), and the piston ( 109 ) and cylinder ( 108 ) define a chamber ( 110 ); force transmitting means for transmitting the force produced on the piston ( 109 ) by gas pressure within the chamber ( 110 ) to the valve stem ( 104 ); and a spring ( 113 ) operating on the piston ( 109 ) and the stem of the valve for applying a force to the stem of the valve tending to close the valve in the event of failure of gas pressure within the chamber ( 110 ), the spring ( 113 ) being positioned so that it is maintained in a compressed condition during normal operation of the valve spring mechanism as a result of gas pressure within the chamber ( 110 ).