Method of staged activation for electronically actuated fuel injectors

Abstract

A staged activation logic is utilized in the transition zone of operation for a fuel injector having an electronically actuated valve that opens to permit flow of high pressure fluid into the injector to initiate injection when activated but is biased to close when deactivated to end injection. Many different types of injectors could potentially utilize the present invention, regardless of whether the high pressure fluid is a high pressure hydraulic actuation fluid or high pressure fuel. The transition zone of operation corresponds to that range of activation durations for the injector in which the electronically actuated valve experiences a bouncing phenomenon because the valve member bounces off of its stop and closes prematurely. If it is determined that the desired amount of fuel to be injected during the next cycle falls within the transition zone of operation, then a revised activation duration for the electronically actuated valve is calculated. The valve is then quickly activated and deactivated with a staging pulse to raise pressure within the injector before actually initiating the injection of fuel. After a brief deactivation period, the electronically actuated valve is actuated for the revised activation duration. If the originally calculated amount of fuel falls outside of the transition zone then the electronically actuated valve is activated in a conventional manner.