Patent ID: 6076491
Filing Date: 2000-06-20
Classification: F01L

Abstract:
A valve control mechanism suitable for use in a valve train which transmits lift from a cam located on a camshaft of an internal combustion engine to a cylinder head valve of the internal combustion engine and which has a first abutment member in abutment with the cam and a second abutment member in abutment with the top of the stein of the cylinder head valve, the valve control mechanism comprising:a first tappet member slidable in a bore in the engine,a second tappet member movable relative to the first tappet member, andlocking means capable of locking the first and second tappet members to move together, whereinwhen the locking mans locks the first and second tappet members to move together the valve control mechanism transmits all of the lift of the cam to the cylinder head valve, andwhen the locking means allows the first and second tappet members to move relative to each other at least a part ofthe lift of the cam causes relative motion between the first and second tappet members rather than lift of the cylinder head valve, whereby the valve control mechanism reduces the amount of lif that is transmitted from the cam to the cylinder head valve,wherein one of the tappet members is connectable with the camshaft only via the other tappet member,the first tappet member which is an outer tappet member which has a bore therein and the second tappet member is an inner tappet member which is slidable in the bore of the outer tappet member,characterised in that the locking means comprises a locking pin slidable in a bore provided in the outer tappet member and a slot provided in the inner tappet member,the locking pin being slidable between a fist position in which the locking pin extends inwardly from the outer tappet member to engage the slot in the inner tappet member and a second position in which the locking pin is out of engagement with the slot in the inner tappet member, and wherein the locking means comprises spring means for biasing the locking pin into the first position and hydraulic fluid supply means operable to supply hydraulic fluid to apply pressure on the locking pin to slide the locking pin from the first position to the second position against the biasing force of the spring means.