| 摘要 |
PURPOSE:To make always precise fuel injection control using a small piezo element by furnishing a degree-of-opening setting member to adjust the opening of a jet, and providing a degree-of-opening adjusting means to operate the setting member and adjust the relative position of the member with the jet. CONSTITUTION:The fuel from a fuel supply device 3 is pressurized by a high pressure pump 2 and introduced to a valve chest 37, and a needle valve 43 is moved up to inject the fuel into the combustion chamber from a jet. When fuel supply from the pump 2 is stopped, the valve 43 is moved down with the energization force of a coil spring 45 so as to block the jet, and thus the injection is stopped. That is, the vertical motion of the valve 43 depends upon the pressurized fuel supply timing from the pump 2. During fuel injection, on the other hand, a piezo element 26 (opening adjusting means) is driven under control by a controller 51 according to the operating condition, so that the element 26 changes the elongation/contraction condition at the time of fuel injection to vary the degree of jet opening appropriately through a throttle shaft 47 (opening setting member), and thereby the fuel injection rate is controlled. In this arrangement it is not required to equip a function to necessarily close the jet fully. |
