| 摘要 |
PURPOSE:To shorten injection period upon high speed high load operation and reduce smoke by a method wherein the valve opening pressure as well as the total area of a nozzle, opened and closed by a valve, of the second needle valve, provided slidably in the first needle valve, are made larger than these of the first valve. CONSTITUTION:When a fuel oil pressure in a fuel reservoir 7 has arrived at a pressure higher than predetermined, the first needle valve 3 is lifted and is separated from a seat surface 13 to communicate the fuel reservoir 7 with the fuel reservoir 8 whereby the fuel in the fuel reservoirs 7, 8 is injected from the injection nozzle 15. When the fuel oil pressure in the fuel reservoir 7 is increased until it overcomes a spring 43, the second needle valve 5 is lifted, contat between a pressure receiving surface 12 and the seat surface 17 is separated and the fuel in the fuel reservoirs 7, 8 is injected from the nozzle 19. Upon high speed and high load operation, the increase of the fuel okl pressure is rapid and an injection phase difference between the opening timing of a valve 5 and the same timing of the valve 3, opened in preceeding to the valve 5, is minute, therefore, the necessary amount of fuel is injected in a short period of time and smoke as well as HC may be reduced. |
