| 摘要 |
PURPOSE:To prevent an exhaust valve from seizing and sticking, by constituting an exhaust valve with an air spring so that the exhaust valve is rotated by the reaction of compressed air which is jetted from an air chamber. CONSTITUTION:A piston 16 disposed in the air chamber 15 of an air spring for urging an exhaust valve 12 in the closing direction of the latter, is formed therein nozzles 101 which are inclined in the radial direction of the piston 16, and as well the lateral wall of the air chamber is formed therein with air vent holes 102. When an engine piston 3 is pushed upward by a cam 1, the pressure in a piston chamber 9 is raised so that a valve rod 11 is depressed downward. When the above-mentioned nozzles 101 is moved down to the level of the air vent holes 102 while air in the air chamber 15 is compressed, the compressed air is jetted through the nozzles 103 and the air vent holes 102 so that the valve rod 11 is rotated by the jet stream of the compressed air. Since the exhaust valve 12 is rotated little by little, thereby it is possible to prevent the exhaust valve from seizing and sticking. |
