Entropy Effect on Output Parameters in Powertrain Otto IC Engine

Abstract

Although today in agriculture the most represented power source are diesel engines, especially for tractors power, Otto engines still have significant impact during operation of agricultural machinery. Where they are most used for power of mowers, cultivators, pumps, or as part of power for plants on farms. It must be added the fact that these engines can easily convert to other fuels such as LPG, CNG or biogas, which are becoming every day more and more competitive. This paper presents a mathematical model of irreversible Otto heat engine. The model was developed to give a clear insight into the effect of generating entropy adiabatic process, final time conducting and losses due to heat transfer. Output power and thermodynamic efficiency of Otto cycle is presented, and the influence of various parameters on this value. Several interesting cases are shown through numerical analysis in the form of diagrams. Emphasis is placed on optimizing of the Otto cycle.

Iako su danas u poljoprivredi najviše zastupljeni dizel motori kao pogonska sredstva, pogotovo kao pogon traktora, otto motori ipak imaju velikog udela kod pogona poljoprivredne mehanizacije. Gde se njihova uloga ogleda uglavnom u pogonu kosačica, motokultivatora, pumpi ili kao sastavni deo postrojenja na farmama. Svakako treba dodati činjenicu da se ovakvi motori veoma lako konvertuju na druga pogonska goriva kao što su TNG, CNG ili biogas čime postaju svakim danom sve konkurentniji. U radu je prikazan ireverzibilan matematički model toplotnog oto motora. Model je razvijen tako da bi se dobio jasniji uvid u uticaj generisanja entropije adibatskih procesa, konačnog vremena odvijanja procesa i gubitaka usled transfera toplote. Izlazna snaga i termodinamička efikasnost ciklusa je predstavljena, kao i uticaj raznih parametara na ove vrednosti. Nekoliko interesantnih slučajeva je prikazano preko numeričke analize u vidu dijagrama. Naglasak je stavljen na optimizaciju otovog ciklusa u cilju uštede energije.