Method of regulating supply pressure in a hydraulically-actuated system

A method of regulating pressure in a hydraulically actuated fuel injection system, comprising the steps of:

• providing a hydraulically actuated fuel injection system having a high pressure pump coupled to an engine and connected to a high pressure rail that is connected to a plurality of hydraulically actuated fuel injectors that each include a control valve;
• periodically activating said control valve sufficiently to perform an injection event;
• determining a fluid pressure in said high pressure rail;
• identifying an idle fuel injector that is between injection events;
• if said fluid pressure is too high, then activating said control valve of said idle fuel injector for a pressure regulation event that is insufficient for said idle fuel injector inject fuel.

A method of operating a hydraulically actuated fuel injection system comprising the steps of:

• providing a hydraulically actuated fuel injection system having a high pressure pump coupled to an engine and connected to a high pressure rail that is connected to a plurality of hydraulically actuated fuel injectors that each include a control valve;
• determining an engine operating condition;
• scheduling injection events based upon said engine operating condition;
• periodically activating said control valve of at least some of said fuel injectors for an amount of time sufficient to perform said injection events;
• determining a fluid pressure in said high pressure rail;
• identifying an idle fuel injector that is between injection events;
• if said fluid pressure is too high, then activating said control valve of said idle fuel injector for a pressure regulation event that is insufficient for said idle fuel injector to inject fuel.