HYDRAULICALLY-ACTUATED ELECTRONICALLY-CONTROLLED UNIT INJECTOR FUEL SYSTEM HAVING VARIABLE CONTROL OF ACTUATING FLUID PRESSURE

摘要

2116531 9307380 PCTABS00021 A hydraulically-actuated electronically-controlled unit injector fuel system (10) and method of operation is disclosed. The fuel system (10) comprises at least one hydraulically-actuated electronically-controlled unit injector (18) and apparatus (20) for supplying hydraulically actuating fluid to the injector (18). The fuel system (10) also includes apparatus for detecting the pressure of the hydraulically actuating fluid supplied to the injector (18) and for generating a pressure indicative signal (S6) indicative of the pressure detected. The fuel system (10) further includes apparatus (24) for controlling the pressure of the hydraulically actuating fluid supplied to the injector (18) and for correcting the pressure amount based on the pressure indicative signal (S6). The present invention provides closed-loop control of actuating fluid pressure which helps ensure that a desired variable pressure setting is achieved and maintained for as long as needed. Accurate control of the actuating fluid pressure helps ensure accurate control of fuel injection timing and quantity.