Lost motion rocker brake biasing and stroke limiting systems

Abstract

Systems for valve actuation in internal combustion engines provide for control of rocker arms and other valvetrain components by utilizing biasing and stroke limited components. Such features may be implemented in any valvetrain component, including e-foot assemblies or pushrod assemblies. The biasing component may bias the cam side of a lost motion rocker toward the cam. The components may be extendable to permit a biasing mechanism to keep the valvetrain components in a controlled position at all times. Stroke limiting features may facilitate the formation of small gaps between valvetrain components during the engine cycle for improved lubrication. Stroke limiting features may also retain valvetrain components in an assembled configuration even when not installed in an engine or valve actuation system.

What is claimed is: 
     
         1 . A system for actuating at least one of two or more engine valves in an internal combustion engine, the system comprising:
 a motion source defining a main event motion profile and an auxiliary motion profile;   a valvetrain for conveying motion from the motion source to the at least one engine valve, the valvetrain having at least two valvetrain components;   a biasing component arranged to apply a biasing force to maintain at least one of the valvetrain components in a controlled state; and   a stroke limited component cooperating with the biasing component and adapted to create a lash gap between the at least two valvetrain components.   
     
     
         2 . The system of  claim 1 , wherein the biasing component is a spring arranged as part of an e-foot assembly. 
     
     
         3 . The system of  claim 2 , wherein the e-foot assembly includes an extendable portion and wherein the spring is arranged to bias the extendable portion towards an extended position. 
     
     
         4 . The system of  claim 2 , wherein the e-foot assembly includes a telescoping portion. 
     
     
         5 . The system of  claim 1 , wherein the stroke limited component is an e-foot assembly. 
     
     
         6 . The system of  claim 5 , wherein the e-foot assembly includes an extendable portion and wherein the extendable portion includes a stop for limiting extension of the extendable portion. 
     
     
         7 . The system of  claim 1 , wherein the biasing component is a spring arranged as part of a push rod assembly. 
     
     
         8 . The system of  claim 7 , wherein the push rod assembly includes an extendable portion and wherein the spring is arranged to bias the extendable portion towards an extended position. 
     
     
         9 . The system of  claim 7 , wherein the push rod assembly includes a telescoping portion. 
     
     
         10 . The system of  claim 1 , wherein the stroke limited component is a pushrod assembly. 
     
     
         11 . The system of  claim 10 , wherein the pushrod assembly includes an extendable portion and wherein the extendable portion includes a stop for limiting extension of the extendable portion. 
     
     
         12 . The system of  claim 1 , where in the valvetrain is a Type 3 overhead cam valvetrain. 
     
     
         13 . The system of  claim 1 , wherein the biasing component or stroke-limiting component comprise e-foot assembly, wherein the e-foot assembly comprises a screw boss, a swivel boss, a pin, a cap, and a bias spring. 
     
     
         14 . The system of  claim 1  wherein the stroke limited component is a pushrod adjustment screw. 
     
     
         15 . The system of  claim 1 , where in the valvetrain is a Type 4 overhead valve valvetrain. 
     
     
         16 . The system of  claim 1 , wherein the biasing component or stroke-limiting component comprise a pushrod assembly, wherein the pushrod assembly comprises a screw boss, a push rod boss, a pin, and a bias spring. 
     
     
         17 . The system of  claim 1 , where in the stroke limited component comprises a pin, a lip, a c-clip or a step for limiting extension of an extendable portion. 
     
     
         18 . The system of  claim 1 , where in the biasing component is arranged to control inertial forces of the rocker arm to prevent a no follow condition between sub-base and base circle of a cam. 
     
     
         19 . The system of  claim 1 , wherein the biasing component is adapted to provide a zero bias load gap between a rocker and a valve bridge at sub-base circle of a cam. 
     
     
         20 . The system of  claim 1 , further comprising a lost motion component cooperating with the valvetrain, the lost motion component being configurable to a first mode, in which the lost motion component absorbs the auxiliary motion, and a second mode, in which the lost motion component conveys the auxiliary motion.