Engine valve actuation system

#The present invention is directed to an engine valve actuation system. More particularly, the present invention is directed to a valve actuation system for an internal combustion engine.

#The operation of an internal combustion engine, such as, for example, a diesel, gasoline, or natural gas engine, may cause the generation of undesirable emissions. These emissions, which may include particulates and nitrous oxide (NOx), are generated when fuel is combusted in a combustion chamber of the engine. An exhaust stroke of an engine piston forces exhaust gas, which may include these emissions, from the engine. If no emission reduction measures are in place, these undesirable emissions will eventually be exhausted to the environment.

#Research is currently being directed towards decreasing the amount of undesirable emissions that are exhausted to the environment during the operation of an engine. It is expected that improved engine design and improved control over engine operation may lead to a reduction in the generation of undesirable emissions. Many different approaches, such as, for example, engine gas recirculation and aftertreatments, have been found to reduce the amount of emissions generated during the operation of an engine. Unfortunately, the implementation of these emission reduction approaches may result in a decrease in the overall efficiency of the engine.

#FIG. 1 is a diagrammatic cross-sectional view of an internal combustion engine in accordance with an exemplary embodiment of the present invention;

#FIG. 2 is a diagrammatic illustration of an exemplary valve actuation assembly for the engine of FIG. 1; and

#FIG. 3 is a graphic illustration of an exemplary valve actuation as a function of engine crank angle for an engine operating in accordance with the present invention.

#An exemplary embodiment of an internal combustion engine 20 is illustrated in FIG. 1. For the purposes of the present disclosure, the engine 20 is depicted and described as a four stroke diesel engine. One skilled in the art will recognize, however, that the engine 20 may be any other type of internal combustion engine, such as, for example, a gasoline or natural gas engine.

#As illustrated in FIG. 1, the engine 20 includes an engine block 28 that defines a plurality of cylinders 22. A piston 24 is slidably disposed within each cylinder 22. In the illustrated embodiment, the engine 20 includes six cylinders 22 and six associated pistons 24. One skilled in the art will readily recognize that the engine 20 may include a greater or lesser number of pistons 24 and that the pistons 24 may be disposed in an “in-line” configuration, a “V” configuration, or any other conventional configuration.

#As also shown in FIG. 1, the engine 20 includes a crankshaft 27 that is rotatably disposed within the engine block 28. A connecting rod 26 connects each piston 24 to the crankshaft 27. Each piston 24 is coupled to the crankshaft 27 so that a sliding motion of the piston 24 within the respective cylinder 22 results in a rotation of the crankshaft 27. Similarly, a rotation of the crankshaft 27 will result in a sliding motion of the piston 24.