Identification of tribological characteristics regarding the optimized construction of reciprocating compressor cylinder for exploitation on motor vehicles

[S. T. Milojević]

182 lista

Primena lakih metala kao što je aluminijum dobija sve više na značaju, ne samo u automobilskoj industriji, već i šire. Primenom konstrukcija aluminijuma se u velikoj meri se štede resursi. Takođe, zbog potpunije reciklaže rashodovanih konstrukcija od aluminijuma, dodatno se smanjuje opterećenje okoline štetnim otpadom. Primenom lakih konstrukcija za izradu delova motornih vozila, zbog smanjenja mase, paralelno se direktno utiče na potrošnju goriva i emisiju izduvnih gasova. Na taj način se povećava ekonomičnost, ali se smanjuje i negativan uticaj motornih vozila na okolinu i uz dodatne mere, moguće je zadovoljiti sve strožije propise i granice dozvoljene emisije izduvnih gasova. Kod primene legure aluminijuma za izradu delova konstrukcije istraživanog klipnog kompresora i motora sa unutrašnjim sagorevanjem, problem predstavlja manja čvrstoća ovog metala, pri čemu treba rešavati i probleme zbog loših triboloških karakteristika i pojačanog trenja i habanja. U slučaju primene aluminijuma za izradu cilindra klipnog kompresora, problem je rešavan primenom prevlaka i ojačanjima od triboloških materijala. Na taj način se može povećati čvrstoća, posebno klizne površine zida cilindra i mogu se poboljšati tribološke karakteristike. U okviru disertacije su istraživane tribološke karakteristike materijala cilindra klipnog kompresora za vazduh sa osnovom od legure aluminijuma i ojačavačima na bazi legure gvožđa, pri uslovima sa i bez sredstva za podmazivanje. Rezultati triboloških ispitivanja su prikazani kao zavisnost koeficijenta trenja i parametara habanja uzorka materijala cilindra sa ojačavačem, od promene brzine i opterećenja u uslovima klizanja, sa i bez prisustva sredstva za podmazivanje. Izvršena je i statistička obrada rezultata triboloških ispitivanja. Analiza rezultata je pokazala koji parametri imaju najviše uticaja na tribološke karakteristike klizne površine cilindra. Na osnovu rezultata statističkih analiza moguće je izabrati i predložiti optimalnu konstrukciju cilindra, ako postoji više rešenja za tribološku optimizaciju klizne površine ili, ako se koriste različita ulja za podmazivanje. Obzirom da je u toku izrade disertacije izvršena tribološka verifikacija konstrukcije cilindra sa ojačavačima klizne površine, za konačan izbor i početak serijske proizvodnje, neophodna su laboratorijska ispitivanja upotrebnih karakteristika klipnog kompresora na probnom stolu. Za tu svrhu je projektovana odgovarajuća instalacija i definisan je postupak ispitivanja. Održavanje sistema referentnog klipnog kompresora je razmatrano sa aspekta pouzdanosti tri kritična podsistema sa paralelnom vezom. Uzimajući u obzir da očekivana vremena održavanja sistema klipnog kompresora potiču iz Rejlijeve raspodele, izvršeno je modeliranje intenziteta održavanja na osnovu raspoloživost

The application of light metals such as aluminum is gaining more and more importance, not only in the automotive industry, but also beyond. Using aluminum constructions saves resources to a great extent. Also, due to the more complete recycling of discarded aluminum constructions, the burden on the environment with harmful waste is additionally reduced. By applying lightweight constructions for the production of motor vehicle parts, due to the reduction in mass, fuel consumption and exhaust gas emissions are directly affected in parallel. In this way, the economy is increased, but the negative impact of motor vehicles on the environment is also reduced, and with additional measures, it is possible to meet the stricter regulations and the limits of permitted emissions of exhaust gases. When using aluminum alloy to make parts of the construction of the researched reciprocating compressor and internal combustion engine, the problem is the lower strength of this metal, while problems due to poor tribological characteristics and increased friction and wear should also be solved. In the case of aluminum application for the production of reciprocating compressor cylinders, the problem was solved by applying coatings and reinforcements consisting of tribological materials. In this way, the strength can be increased, especially the sliding surface of the cylinder liner, and the tribological characteristics can be improved. As part of the dissertation, the tribological characteristics of the reciprocating air compressor cylinder base material consisting of aluminum alloy and reinforcements made of iron alloy were investigated under conditions with and without a lubricant. The results of the tribological tests are shown as the dependence of the coefficient of friction and wear parameters of the cylinder material sample with reinforcement on the change in speed and load in sliding conditions, with and without the presence of a lubricant. Statistical processing of the results of tribological tests was also performed. The analysis of the results showed which parameters have the most influence on the tribological characteristics of the sliding surface of the cylinder. Based on the results of statistical analyses, it is possible to choose and propose the optimal construction of the cylinder if there are several solutions for the tribological optimization of the sliding surface or if different lubricating oils are used. Since the tribological verification of the cylinder construction with reinforcements was carried out during the preparation of the dissertation, for the final selection and the decision for the cylinder serial production, laboratory tests of the reciprocating compressor on the test bench are necessary. For this purpose, a suitable installation was designed, and the test procedure was defined. Maintenance of the reciprocating compressor system is considered from the reliability aspect of three critical subsystems with parallel connections. Taking into account that the expected maintenance times of the reciprocating compressor system come from the Rayleigh distribution, the maintenance intensity was modeled based on availability.

aluminijum, dinamika ventila, eksploatacija, emisija izduvnih gasova, klipni kompresor, motor sa unutrašnjim sagorevanjem, pouzdanost, održavanje i tribologija

aluminum, valve dynamics, exploitation, exhaust emission, reciprocating compressor, internal combustion engine, reliability, maintenance and tribology

621.512.3:62-222.2(043.3)

Tekst