Dual-jet fuel injector with pneumatic assistance in spray generation for an internal combustion engine fed by injection

Claim 1

A dual-jet type fuel injector for feeding an internal combustion engine having at least two intake valves per combustion chamber of the engine, feed being by injecting fuel through two calibrated holes of the injector for delivering respective fuel jets along mutually diverging axes towards the two valves, the holes being formed in a nose designed to face towards the two valves, the nose belonging to a body of the injector that also has a shutter which is constrained to move in translation with an electromagnet core and which is urged towards a position for closing the calibrated holes by resilient return means against which the shutter is moved away from the calibrated holes by feeding electricity to a control winding of the electromagnet so as to deliver at least two jets of fuel, the two calibrated holes opening out into a zone for spray generation with pneumatic assistance, which zone is defined in part by a pneumatic spray-generation adapter forming a channel substantially around the nose of the injector and fed with air substantially at atmospheric pressure for assisting in spray generation and in other part by a portion of two intake manifold ducts, the adapter having a plurality of defined holes for passing air from the channel towards the zone and said defined holes having axes that extend substantially transversely to the fuel jets so as to assist pneumatically in breaking up said jets into spray, wherein the defined holes for passing air are distributed in the adapter in such a manner that when the winding of the electromagnet is powered, and while the engine is under heavy load, causing a low pressure gradient between the channel and the spray generation zone, thereby feeding assistance air at a limited flow rate such that two jets of fuel passing through the calibrated holes cross the spray-generation zone towards the two intake manifold ducts, whereas while the engine is idling and while it is under low to medium load, causing the pressure gradient to be high, one of the jets of sprayed fuel is deflected by the jets of air penetrating through the defined holes into the spray-generation zone towards the other fuel jet with which it mixes to form a single jet of fuel spray, confined within only one of the manifold ducts, so that the fuel is injected selectively into one or both of the two manifold ducts.