NG Fuel Injectors

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Powertrain Control Module (PCM) controls fuel injector pulse width ("on" time) to meter fuel quantity into intake ports. The PCM receives inputs from engine sensors to compute fuel flow necessary to maintain correct air/fuel ratio throughout entire engine operating range. Injector pulse width is the only controlled variable in fuel delivery system.

Each cylinder has a solenoid-operated injector that sprays fuel toward the back of each intake valve. Fuel injector nozzles are solenoid-operated valves which meter and atomize fuel delivered to engine. Each injector is normally closed and receives 12 volts VPWR from power relay. The PCM controlled ground circuit is used to complete the circuit and energize the injector.

Flow capacity of natural gas fuel injectors is 6-12 times greater than typical gasoline fuel injectors. Also, injector resistance (4.6 ohms) is less than gasoline fuel injectors (14.5 ohms). To accommodate the lower resistance, a Fuel Injector Driver Module (also referred to as Natural Gas (NG) module, is used to convert PCM fuel injector driver signal to the signal required by fuel injector.