Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
INFLUENCE OF SPEED AND LOAD VARIATION ON THE ENERGY BALANCE OF AN INTERNAL COMBUSTION ENGINE WITH GASOLINE
Submission Author:
Claudio Santana , MG , Brazil
Co-Authors:
Claudio Santana, Luís Antônio Bortolaia
Presenter: Claudio Santana
doi://10.26678/ABCM.COBEM2021.COB2021-0436
Abstract
The Otto cycle vehicle engine is a thermal machine that operates from the combustion of gasoline and ethanol inside the combustion chamber. A considerable part of this released thermal energy is used for the operation of the engine, with the remaining energy lost to the cooling system, exhaust system, lubrication system, incomplete combustion and the environment (convection and radiation). The way to detect this loss for the purpose of optimizing performance, is through the experimental test and applying the thermal balance to the engine. The objective of this work is to perform a thermal balance in an Otto cycle engine involving the energy released due to the gasoline combustion process, power extracted from the engine shaft, rejected energy rates for the cooling system, for the exhaust system, for the lubrication system and for the environment in the form of heat and incomplete combustion, depending on the variation of engine speed and load. The experiment consisted of making measurements on an Otto cycle engine on a bench dynamometer varying engine speed and load, which made it possible to collect data to make the engine's thermal balance. The results showed that variations in engine speed and load influence the distribution of rates and efficiencies in the engine's thermal balance. At full load and in the condition of better thermal performance of the engine, thermal efficiency, the efficiency of the cooling, exhaust, lubrication, incomplete combustion and environmental systems were 30%, 12%, 29%, 5%, 0, 6% and 22%, respectively. Reducing the load causes a reduction in thermal efficiency and an increase in other efficiencies. Increasing the speed to the point of better thermal performance of the engine causes an increase in thermal efficiency, after which the increase in speed decreases the thermal efficiency and increases the other efficiencies. This research is important because it correlates the useful energy in an Otto cycle engine with the actual losses and this allows, based on the detected energy losses, an opportunity for a more detailed study to optimize and improve the performance of the engine.
Keywords
Otto cycle gasoline engines, thermal balance, Thermal Efficiency, bench dynamometer measurement, engine performance parameters
