| 摘要 |
A wide variety of machines have moveable members that are operated by an hydraulic actuator. For example, an internal combustion engine has a camshaft which is mechanically coupled to rotate with the crankshaft and which opens and closes cylinder intake and exhaust valves. Traditionally the camshaft timing was fixed at a setting that produced the best operation for all engine operating conditions. However, it has been recognized that engine performance can be improved if the valve timing varies as a function of engine speed, engine load, and other factors. Thus a hydraulic actuator is being used on some engines to vary the coupling relationship of the camshaft to the crankshaft. A solenoid operated valve controls the application of pressurized fluid to operate the hydraulic actuator. |
