OPTIMIZATION OF METHODS AND PARAMETERS OF PRE-START THERMAL PREPARATION OF THE ENGINE FOR STARTING DEPENDING ON THE AMBIENT TEMPERATURE

Due to the lack of a generally accepted methodology for calculating the starting processes of automotive diesel engines, today it is not possible to calculate their temperature parameters with a sufficient degree of accuracy during start-up, which determine the condition of a guaranteed start-up process. The main problem in applying theoretical calculations is that they take into account the compression ratio of the engine. But the compression ratio and the value of the actual pressure in the engine cylinders during the start-up are completely different indicators. The purpose of this work is to correct the generally accepted dependencies for determining the temperature parameters of a diesel engine by introducing a correction factor that takes into account the reduced pressure in the engine cylinders during start-up, as well as calculating the temperature parameters during start-up according to the proposed calculation method. The correction factor is determined experimentally and depends on the engine temperature. When applying the correction factor, it becomes possible to accurately calculate the temperature of the fuel-air mixture, which determines the possibility of a guaranteed start-up process and at the same time allows you to set the minimum necessary requirements for the means of thermal pre-start preparation. A group of graduate students and teachers (Izhevsk State Agricultural Academy and Kazan Agrarian University) conducted a number of practical studies on the basis of one of the leading agricultural enterprises of the Udmurt Republic JSC "Ilyich's Way". The MTZ-82 tractor was taken as the object of the study. The subject of the study was the launch of its D-243 engine at low temperatures in real operating conditions. The choice of this model of diesel engine is due to its wide application on tractors. The studies were carried out according to the approved test program, which consists in starting the D-243 engine of the MTZ-82 tractor at temperatures from - 30 ° C with an interval of 5 ° C to +5 ° C (engine temperature is equal to ambient temperature), as well as from +5 ° C to +90 ° C with an interval of 20 ° C (ambient temperature +20 ° C). Measurements were carried out to determine the amount of compression in the engine cylinders and the speed of rotation of the crankshaft at certain temperatures. The experiments were carried out using a starter charger that provides the full electric power of the diesel starter. As a result of the experimental work carried out, a change in the value of the correction coefficient from the engine temperature was established, and in accordance with the modified methodology of theoretical calculations, the values of the temperature of the fuel-air mixture at the end of the compression stroke of the diesel engine at start-up are given. It is established that the minimum required pre-start temperature of the diesel engine should be at least +5 ° C. Based on the results of the analysis of calculations, the directions of ensuring a guaranteed start of the diesel engine by simultaneously heating the coolant and engine oil are proposed. These requirements can be provided by a thermal storage system that does not require additional energy sources for its operation

Enhanced Mechanical and Tribological Capabilities of a Silicon Aluminum Alloy with an Electroplated Ni–Co–P/Si3N4 Composite Coating

Ni–Co–P/Si3N4 composite coatings were fabricated over an aluminum–silicon (Al–Si) substrate using a pulse-current electroplating process, in which the rapid deposition of an intermediate nickel–cobalt layer was used to improve coating adhesion. The microstructure, mechanical, and tribological behaviors of the electroplated Ni–Co–P/Si3N4 composite coating were characterized and evaluated. The results revealed that the electroplated Ni–Co–P/Si3N4 composite coating primarily consisted of highly crystalline Ni–Co sosoloid and P, and a volumetric concentration of 7.65% Si3N4. The electroplated Ni–Co–P/Si3N4 composite coating exhibited hardness values almost two times higher than the uncoated Al–Si substrate, which was comparable to hard chrome coatings. Under lubricated and dry sliding conditions, the electroplated Ni–Co–P/Si3N4 composite coating showed excellent anti-wear performance. Whether dry or lubricated with PAO and engine oil, the composite coating showed minimum abrasive wear compared to the severe adhesive wear and abrasive wear observed in the Al–Si substrate.

The Effects of Using Waste Engine Oil Bottom on Physical, Rheological Properties and Composite Modification Mechanism of SBS-Modified Asphalt

This research explores the effects of using waste engine oil bottom on physical, rheological properties and composite modification mechanism of SBS-modified asphalt. The SBS asphalt binder was modified by WEOB with different concentrations (2, 4, and 6 wt%). The GC-MS and FTIR spectrometry were conducted to evaluate the chemical compositions of WEOB- and WEOB-modified asphalt. RV, DSR, and BBR were tested to evaluate high- and low-temperature pavement performance. Fluorescence microscope (FM) test, bar thin layer chromatograph (BTLC) test, and AFM test were performed to evaluate the micromorphologies and modification mechanism. The test results showed that a new characteristic peak appeared in the infrared spectrum of the WEOB-modified SBS asphalt, indicating a chemical reaction in the modification process. Incorporation of WEOB improves both the high-temperature and low-temperature properties of the SBS asphalt binder. It was confirmed that with the increase of WEOB concentration, the content of colloid gradually increases, which promotes the swelling and compaction of SBS polymer network structure. Furthermore, WEOB promotes the polarity of SBS and forms graft product MAH-g-SBS with asphalt, thus inhibiting the thermal movement of asphalt molecules. On the contrary, light components have a good correlation with the surface roughness of modified asphalt; the results show that the modified asphalt has good rutting resistance.

Biodegradation of petroleum by bacteria isolated from fishes of Indian Ocean

In this study, oil degrading bacteria discovered from fish living near the oil ports at Karachi in Pakistan were characterized. The bacteria isolated from skin, gills, and gut in fish could consume crude oil as a source of carbon and energy. Total 36 isolates were tested using Nutrient Agar (NA) and MSA media with different crude oil concentrations (0.2%, 0.5%, 0.7%, 1%, 2%, and 5%) and 4 out of 36 isolates (two Gram positive and two Gram negative bacteria) were selected for further identification. 16S rRNA gene sequencing revealed that the isolates are related to Bacillus velezensis, Bacillus flexus, Pseudomonas brenneri and Pseudomonas azotoforman. Oil degrading potential of these bacteria was characterized by GC-MS analysis of degradation of oil components in crude oil as well as engine oil. We found that one (2, 6, 10, 14-Tetramethylpentadecane) out of 42 components in the crude oil was fully eliminated and the other oil components were reduced. In addition, 26 out of 42 oil components in the engine oil, were fully eliminated and the rest were amended. Taken together, these studies identify that B. velezensis, B. flexus, P. brenneri and P. azotoforman have high oil degrading potential, which may be useful for degradation of oil pollutants and other commercial applications.

Multiple Stress Creep Recovery (MSCR) Test for Determination of Waste Engine Oil Modified Asphalt Binder as Pavement Material

Engineers have been using modified binders to improve the quality of flexible pavements. The use of waste material is one of the solutions taken in this direction. It is for this ground that the studies emphasis on the evaluation of waste engine oil as a modifier for asphalt binder as a pavement material. In the study uses four samples extracted from 80/100 penetration grade bitumen. From four sample first sample was checked for weather requirements of asphalt binder meet or not and the three were modified with different content of engine oil (3,6 and 9%). The behaviors of both unmodified and modified binder were checked for rheological properties. Dynamic shear rheometer (DSR) was used to determine high temperature performance grade (PG) and multiple stress creep recovery tests to determine rutting resistance properties of the binder. PG analysis indicates that both aged and un-aged 3% and 6% modified binder have similar higher PG grade with the unmodified one and 9% modified to have lower PG vale. Jnr3.2 value of modified asphalt binder is lower than unmodified binder indicating that modification had improved the rutting resistance and design traffic load (ESALS). The study shows that it is possible to use waste engine oil-modified binder as a pavement material.