Internal combustion engines in which two injectors are provided for each cylinder in an intake manifold are already known. Eight injectors may therefore be provided in such a four-cylinder spark-ignition engine. The two injectors assigned to an individual cylinder inject fuel into a region of a branching point of the intake manifold in order to admit a fuel-air mixture formed there into the particular cylinder through two separate intake valves. For internal combustion engines having two intake valves per cylinder, this has the advantage that less fuel is directed toward a bridge at the branching point of the intake manifold and deposited there than in internal combustion engines having only a single injector per cylinder. The deposited fuel quantity is difficult to ascertain, so that the dosing of the precise quantity of the fuel admitted into the cylinder becomes more difficult.
One aspect in the construction of an injection systems for an internal combustion engine is that a homogeneous fuel-air mixture is present in the cylinder of the internal combustion engine at the ignition instant. In conventional internal combustion engines this air-fuel mixture is produced in the area in front of the intake valves. The fuel spray injected by the injectors into the corresponding intake manifold region evaporates there and is aspirated into the individual cylinder by a corresponding piston movement at the intake instant. Toward this end, the injection of the fuel into the corresponding intake-manifold section usually takes place ahead of time, so that a certain period of time is available for the evaporation of the fuel droplets in the fuel spray. This is required especially in the operating ranges that feature higher loads.
USPTO Backgrounds
USPTO Backgrounds