PURPOSE: To prevent the air-fuel ratio from becoming lean without increasing the capacity of an air compressor, in the fuel injector based on the use of an air blast valve device, by causing an increase in the amount of compressed air being injected from a nozzle port during acceleration operation of the engine.
CONSTITUTION: In an air blast valve device 20 disposed at the inner wall surface of a cylinder head 3, when a solenoid 30 is energized with the result that a needle 23 acts on a valve portion 25 to open a nozzle port 24, the previously supplied fuel which remains in the vicinity of the valve portion 25 is injected, together with a compressed air, into a combustion chamber 4 via the nozzle port 24. On the other hand, when the needle 23 opens the nozzle port 24, a compressed air flows from a compressed-air inflow passageway 33 into a nozzle chamber 32 and goes toward the nozzle port 24. In this air blast valve device 20, part of the fuel stays within the valve device 20 and this residual amount of fuel increases as the supplying amount of fuel increases. In this view, during acceleration operation, the supplying amount of compressed air is increased to prevent an increase in the residual amount of fuel within the air blast valve device 20, thus to prevent the air-fuel ratio from becoming lean.
NOMURA KENICHI
TAKANO YUICHI
NIHEI HIROAKI
