Abstract: An air-assist fuel injection system controls the supply of compressed air to the fuel injectors according to the operating status of internal combustion engine. For cold start operation, compressed air is supplied continuously to the injectors; while, for partial load (cruising) and partial acceleration, air is supplied as a pulsating (air volume control) flow consisting of air pulses coincident with the injected fuel pulses. On the other hand, for acceleration and deceleration, the supply of compressed air to the injectors may be inhibited. Further, idle speed control can be achieved using the air-assist to the fuel injectors, thereby eliminating need for a separate idle speed control valve. To enhance system operation, a fuel injector may be employed in which both the fuel and the applied compressed air are swirled, but in opposite directions, so as to achieve a fuel spray of small particle size.

Abstract: An air-assist fuel injection system controls the supply of compressed air to the fuel injectors according to the operating status of internal combustion engine. For cold start operation, compressed air is supplied continuously to the injectors; while, for partial load (cruising) and partial acceleration, air is supplied as a pulsating (air volume control) flow consisting of air pulses coincident with the injected fuel pulses. On the other hand, for acceleration and deceleration, the supply of compresseed air to the injectors may be inhibited. Further, idle speed control can be achieved using the air-assist to the fuel injectors, thereby eliminating need for a separate idle speed control valve. To enhance system operation, a fuel injector may be employed in which both the fuel and the applied compressed air are swirled, but in opposite directions, so as to achieve a fuel spray of small particle size.