Desmodromic hydraulic valve train

摘要

The mass production of the MultiAir/UniAir of Fiat/INA proves that the hydraulic control can reliably actuate the valves of the modern internal combustion engines, making them greener. Removing the valve springs from the valves and controlling by the cam not only the valve opening but also the valve restoring, the hydraulic system has easier work to do, the rev limit increases, the height and the cost of the engine decrease and the engine can operate according all the MultiAir strategies.;Optionally, the control by high speed solenoid valves can be replaced by easier and cheaper control wherein the rotation of the oil piston is what varies the valve lift and the valve duration. If necessary, slow, cheap, low power servomotors can micro-align the angular displacement of different oil pistons to balance the load between the cylinders.

主权项

1. A desmodromic hydraulic valve train for reciprocating piston engines and pumps comprising at least:
a valve (1) comprising a valve piston (2) and a valve stem (3), the valve piston (2) is secured to the valve stem (3); an opening oil chamber (4), one end of the valve piston (2) is slidably fitted and seals one side of the opening oil chamber (4); a closing oil chamber (5), another end of the valve piston (2) is slidably fitted and seals one side of the closing oil chamber (5); a cam (6); an oil piston (7); an oil chamber (8), the oil piston (7) is slidably fitted and seals one side of the oil chamber (8), the cam (6) moves in synchronization to the engine or pump and forces the oil piston (7) to perform an actuating motion wherein the oil piston displaces oil out of the oil chamber (8); an oil reservoir (11), the cam (6) controls an oil piston (7) restoring motion wherein oil from the oil reservoir (11) enters into the oil chamber (8); control means (71), (10), and channels (9) connecting controllably the opening oil chamber (4) and the closing oil chamber (5) with the oil chamber (8) and the oil reservoir (11), the actuating motion of the oil piston comprises an initial part wherein the oil from the oil chamber is directed, according to a state of the control means, either to the opening oil chamber and displaces the valve to open positively, or to the closing oil chamber and displaces the valve to close positively, the actuating motion of the oil piston comprises a final part wherein the oil from the oil chamber is directed to the closing oil chamber and displaces the valve to close positively, the final part of the actuating motion is adequately long to guarantee that at the end of the actuating motion of the oil piston the valve will be closed.