| 摘要 |
Hydraulically driven pump-injector with controlling mechanism for internal combustion engines, primarily for diesel, distinguished via the fact that in the pump-injector body ( 1 ) above needle ( 9 ) additional cylindrical cavity ( 69 ) is made, in which locking piston ( 8 ) is mounted, resting upon needle ( 9 ), the diameter of said additional cavity and hence the piston diameter being selected on the basis of the formulae disclosed in the invention. Space ( 24 ) formed above the piston face is periodically connected through distribution channel ( 25 ) and valve ( 33 ) of the distributing device to the source of the actuating fluid and the drain tank, alternately. This ensures a decrease in the delay of the operation on the nozzle needle compared to the signal from the electronic control unit (travel of the valve of the distributing device), required for obtaining small time delays between the injections in multiphase injection, as well as increased stability of the idle running of the engine. In accordance with the invention, penetration of gases from the combustion chamber to the fuel system and leaking of fuel into the combustion chamber when the nozzle needle "hangs", or "freezes" in it's upper open position, are also prevented due to the fact that the fuel (actuating fluid) is supplied to the under-plunger cavity ( 19 ) through central channel ( 33 ) in the body, which stops locking piston ( 8 ) of needle ( 9 ) when the latter "hangs". The invention also allows for increasing average injection pressures and implementing "rate shaping".
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