FUEL PRESSURE MEASUREMENT AND RELATED PROCESSES, SYSTEMS, AND CONTROLS

A system and process of operating an internal combustion engine system includes a fuel injector in fluid communication with a fuel rail operable to inject fuel during an engine cycle. A high pressure pump is connected to the fuel rail and includes pumping elements that pressurize the fuel and discrete quantity inlet metering valves that control the fuel flow from the pumping elements. Fuel flow from the pumping elements of the high pressure pump to the fuel rail is terminated by the discrete quantity inlet metering valves during a portion of the engine cycle in order to obtain fuel pressure measurements of the fuel rail while fuel is being injected.