Modello dinamico di iniettore di gas per motore ad accensione comandata

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Abstract

[automatically translated] In this paper we study the complex dynamics of a shutter solenoid gas injector for a spark-ignition engines; as is known, it is subjected to pressures of different nature and its motion has a decisive influence in respect of the supplied fuel mass, which is normally modulated by acting on the length of the solenoid, called "injection time ". For the shutter is completely opened, the mass of gas which passes through the injector outlet section depends exclusively on the fluid conditions at the injector and upstream of the length of the injection time: this makes the linear characteristic of the injector operation, understood as relationship between the injected mass and the injection time. However, the authors have experimentally observed that, due to transient phenomena, for low injection times, the injector characteristic deviates strongly from linearity, making it less accurate control of the injected fuel mass and thus of the measuring operation. This has a negative influence both on fuel consumption on both the containment of the polluting emissions at the minimum loads, since the efficiency of the pollutant reduction system, based on three-way catalyst, is low dosages for different operation from that of stoichiometric. Moreover, a recent experimental study conducted by the same authors on an innovative power mode of the bi-fuel engines, called "Double Fuel" [1], has shown that the simultaneous combustion of gasoline and natural gas involves considerable advantages in terms of reduction of pollutants is both of fuel consumption, since it allows to feed the engine with globally stoichiometric mixture even in full load conditions; this third mode the power of the bi-fuel engines, requiring more reduced amounts of both fuels, of course, involves the use of the injectors in the characteristic with low injection times area, with obvious drawbacks on the operation of measuring control. On the basis of these premises, the authors decided to study in detail the operation of a gas injector for a positive ignition engine in order to improve the response to the lower injection times. The study consists of a theoretical part,
Original languageItalian
Number of pages0
Publication statusPublished - 2010

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