Search results for "Fuel injection"
showing 5 items of 5 documents
A mathematical model for the prediction of the injected mass diagram of a S.I. engine gas injector
2013
A mathematical model of gaseous fuel solenoid injector for spark ignition engine has been realized and validated through experimental data. The gas injector was studied with particular reference to the complex needle motion during the opening and closing phases, which strongly affects the amount of fuel injected. As is known, in fact, when the injector nozzle is widely open, the mass flow depends only on the fluid pressure and temperature upstream the injector: this allows one to control the injected fuel mass acting on the “injection time” (the period during which the injector solenoid is energized). This makes the correlation between the injected fuel mass and the injection time linear, e…
A Simulation Study Assessing the Viability of Shifting the Location of Peak In-Cylinder Pressure in Motored Experiments
2020
Hybrid powertrains utilize an engine to benefit from the power density of the liquid fuel to extend the range of the vehicle. On the other hand, the electric machine is used for; transient operation, for very low loads and where legislation prohibits any gaseous and particulate emissions. Consequently, the operating points of an engine nowadays shifted from its conventional, broad range of speed and load to a narrower operating range of high thermal efficiency. This requires a departure from conventional engine architecture, meaning that analytical models used to predict the behavior of the engines early in the design cycle are no longer always applicable. Friction models are an example of …
Desktop X-ray tomography for low contrast samples
2013
Abstract Based on the experience in the use of polycapillary optical systems, recently XLab Frascati LNF and IM CNR have been strongly involved in studying the techniques for high resolution X-ray Imaging and micro-tomography that intends in the development of a new imaging instrument to examine low contrast samples complicated by fast developing processes. In order to get the reliable signal to noise ratio, typically available via synchrotron radiation (SR) dedicated X-ray optical devices, for the desktop solutions we have to increase the radiation fluxes from conventional sources. As known, manipulated through polycapillary optics beams result in getting higher fluxes with respect to a pi…
Performances improvement of a S.I. CNG bi-fuel engine by means of double-fuel injection
2009
Natural gas represents today a promising alternative to conventional fuels for road vehicles propulsion, since it is characterized by a relatively low cost, better geopolitical distribution than oil, and lower environmental impact. This explains the current spreading of Compressed Natural Gas (CNG) fuelled S. I. engine, above all in the bi-fuel version, i.e. capable to run either with gasoline or with natural gas. This characteristic, on the one hand, permits the vehicle to go even when natural gas is not available, on the other hand requires the engine to be designed to run safely with gasoline, i.e. with compression ratio lower than what natural gas would allow. Moreover the electronic co…
Experimental model-based linearization of a S.I. engine gas injector flow chart:
2014
Experimental tests previously executed by the authors on the simultaneous combustion of gasoline and gaseous fuel in a spark ignition engine revealed the presence of strong nonlinearities in the lower part of the gas injector flow chart. These nonlinearities arise via the injector outflow area variation caused by the needle impacts and bounces during the transient phenomena that take place in the opening and closing phases of the injector and may seriously compromise the air-fuel mixture quality control for the lower injection times, thus increasing both fuel consumption and pollutant emissions. Despite the extensive literature about the operation and modelling of fuel injectors, there are …