Development of a Novel Fuel Injection System (NFIS) for Dimethyl Ether-and Other Clean Alternative Fuels

Common rail (CR) diesel fuel injection systems are very sensitive to variations in fuel properties, thus the impact of alternative fuels on the durability of the injection system should be investigated when considering the use of alternative fuels. This work studies a high-pressure CR (HPCR) diesel fuel injection system operating for 400 h in an injection test bench, using a fuel blend composed of an alternative paraffinic fuel and conventional diesel (50PF50D). The alternative fuel does not have aromatic components and has lower density than conventional diesel fuel. The injection system durability study was carried out under typical injection pressure and fuel temperature for the fuel pump, the common rail and the injector. The results show that the HPCR fuel injection system and its components (e.g., piston, spring, cylinder, driveshaft and cam) have no indication of damage, wear or change in surface roughness. The absence of internal wear to the components of the injection system is supported by the approximately constant total flow rate that reaches the injector during the whole the 400 h of the experiment. However, the size of the injector nozzle holes was decreased (approximately 12%), being consistent with the increase in the return fuel flow of the injector and rail (approximately 13%) after the completion of the study. Overall, the injection system maintained its operability during the whole duration of the durability study, which encourages the use of paraffinic fuels as an alternative to conventional diesel fuel.

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Impact of physical properties of mixture of diesel and biodiesel fuels on hydrodynamic characteristics of fuel injection system

Thermal Science ◽

10.2298/tsci130513010f ◽

2014 ◽

Vol 18 (1) ◽

pp. 143-153

Author(s):

Ivan Filipovic ◽

Boran Pikula ◽

Goran Kepnik

Keyword(s):

Physical Properties ◽

Diesel Fuel ◽

Alternative Fuels ◽

Fuel Injection ◽

Combustion Process ◽

Injection System ◽

Biodiesel Fuel ◽

Fuel Injection System ◽

Biodiesel Fuels

One of the alternative fuels, originating from renewable sources, is biodiesel fuel, which is introduced in diesel engines without major construction modifications on the engine. Biodiesel fuel, by its physical and chemical properties, is different from diesel fuel. Therefore, it is expected that by the application of a biodiesel fuel, the characteristic parameters of the injection system will change. These parameters have a direct impact on the process of fuel dispersion into the engine cylinder, and mixing with the air, which results in an impact on the quality of the combustion process. Method of preparation of the air-fuel mixture and the quality of the combustion process directly affect the efficiency of the engine and the level of pollutant emissions in the exhaust gas, which today is the most important criterion for assessing the quality of the engine. The paper presents a detailed analysis of the influence of physical properties of a mixture of diesel and biodiesel fuels on the output characteristics of the fuel injection system. The following parameters are shown: injection pressure, injection rate, the beginning and duration of injection, transformation of potential into kinetic energy of fuel and increase of energy losses in fuel injection system of various mixtures of diesel and biodiesel fuels. For the analysis of the results a self-developed computer program was used to simulate the injection process in the system. Computational results are verified using the experiment, for a few mixtures of diesel and biodiesel fuels. This paper presents the verification results for diesel fuel and biodiesel fuel in particular.

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