PSI - Issue 16

276 Jacek Eliasz et al. / Procedia Structural Integrity 16 (2019) 273–280 Jacek Eliasz et al. / Structural Integrity Procedia 00 (2019) 000 – 000 As a result of the fuel contact with the catalyst, the reaction of dehydrogenation of paraffin hydrocarbons to the olefinic form occurs, according to the diagram in Fig. 2. The platinum catalyst was applied by the electrospark method (Pehan et al. (2009), Osipowicz et al. (2014)).

3. Wear of precision pairs elements in the injection system using plant-origin fuels

Elements of individual engine components undergo wear processes. Modern self-ignition engines consist of many cooperating systems that are dependent on each other. Each failure affects the work of other components. For example, inefficient fuel injectors cause faster wear of elements of the intake and exhaust systems, and this will cause deterioration of the engine's ecological parameters. Therefore, when discussing issues related to the ecology of modern internal combustion engines, the aspects of their operation should be taken into consideration. The field of technical diagnostics is connected with the correct exploitation of internal combustion engines. The proper diagnostic process enables quick locating of failures and their removal. Searching for new solutions, whose task is to improve ecological indicators of the engines, attention should be paid to the durability of individual components. The durability parameter has a significant effect on the use of alternative fuels as well as making structural changes to individual components. Sundus et al. (2017) showed the effect of using plant-origin fuels on engine components such as piston, rings, cylinder, connecting rods and bearings for issues related to tribological wear. The analysis showed that wear caused by friction and the phenomenons of corrosion are of key importance when using plant origin fuels. Research has shown that the use of biofuel in the short term reduces the processes of corrosion and wear of engine components. This is due to the fact that plant-origin fuels have a tendency to absorb moisture, therefore, it is not advisable to store them in the long run. In addition, during high temperatures biofuel is oxidized, which increases the water content. The authors suggested that the appropriate refining additives should affect the accelerated aging process of the tested fuel, which will improve its tribological parameters (Sundus et al. (2017)). Studies on the dependence of friction forces on the contents of the biocomponent were investigated by the authors in the work (Hamdan et al. (2017)). The friction properties are presented according to the division of raw materials for the production of biofuels due to cloud points in two groups: raw materials from winter cropsand the second group from summer crops, animal fat and hydrogenated vegetable oil. The analysis was carried out according to two indicators presented by the authors: the average friction force of elastohydrodynamic lubrication (EHL) and the average friction force of the boundary lubrication (BL). Research has shown that by increasing the FAME content in diesel oil, we reduce friction forces according to the analyzed EHL and BL indices. The best raw material in terms of lubricating properties was soybean oil due to the lowest friction forces and the highest liquidity. Pehan et al. (2009) presented the effect of methyl ester of B100 rapeseed oil on tribological wear of engine components with mechanical injection system. The tests involved the use of fuels: diesel oil, biofuel B100 and oil for calibration of ISO 4113 fuel injectors. Research has shown that B100 fuel accelerates the wear of injection pump components. There were visible abrasions on the pistons. According to the authors, this was not affected by the lubrication parameters of the tested biofuel. The soot content on the fuel injector atomizers was at a similar level when using B100 and ON fuels. The content of residues inside the fuel injectors was also similar. Simulation analysis of injection characteristics at the temperature of 273 K and 293 K was also carried out. The analysis showed that the injection volumes for different temperatures were almost the same. The wear of components of the injection apparatus and the combustion process in the self-ignition engine is influenced by the method of storing plant-origin fuels. The aging process of biofuels is associated with the operation of fuel supply systems. Fuel as a result of the aging process changes its physical and chemical properties. The publication of Saltas et al. (2017) examined the effect of aging biofuels used in Europe B0, B7, B20 and B100 on the production of sediments in the Common Rail injection system. B100 fuel was produced in 50% from rapeseed oil and 50% soybean oil. The time of deterioration of the technical condition of the injection equipment was assessed on the basis of the total acid number of the fuel tested. Studies have shown that the size of total acid number of fuel affects the time of failure of injection systems. For injection pumps, the critical value of the total acid number was around 0.2 mg KOHg regardless of the content of the biocomponent (7 … 20%). In the case of fuel injector malfunctions, the critical value of the total acid number is within the range of 0.2 – 0.4 KOHg and is inversely proportional to the content of the biocomponent in the fuel (the higher the biocomponent content, the lower the total acid number).