Air assist fuel injection system with compressor intake throttle control

An air-assisted fuel injection system for an engine, the system including an air compressor adapted to be driven by the engine and having an air inlet and an air outlet, the outlet connected with air-assisted fuel injectors for the engine, and an air pressure regulator connected with the compressor air outlet for controlling air pressure in the outlet by exhausting excess air delivered by the compressor to the outlet, wherein the system further comprises:

• a throttle valve in the compressor inlet and operable by a controller to variably restrict inlet air flow to the compressor;
• and
• an air flow sensor responsive to an indicator of the flow of excess air exhausted by the air pressure regulator, the sensor being connected with the controller for variably closing or opening the throttle in response to increasing or decreasing excess air flow, thereby controlling the amount of excess air delivered by the compressor and limiting parasitic losses from pumping of excess air by the compressor.