Cosmina BOCA, Adrian MURA, Radu ILEA, Anișoara DUMA-COPCEA None ileaupc@yahoo.com
In this paper, we present the results of a comparative study of the internal combustion engines used to the operation of machines from agriculture, transport and industry. Internal combustion engines convert the kinetic energy of the combustion gases into mechanical energy, by the action of their own pistons that have an alternative translation motion. Through the connecting rods the translation motion becomes a rotation motion of the crankshaft. At the four-stroke cycle, the succession of the processes is carried out at four piston strokes, i.e. at two rotations of the crankshaft. The periodic resumption of the motor cycle requires the emptying of the cylinders of the combustion gases, followed by the filling of the cylinders with another air-fuel mixture. The caloric energy, produced by the combustion of the fuel, is converted into mechanical energy by 25-40%, which represents the yield of the internal combustion engine. The power transmitted by the internal combustion engine, through the crankshaft, is given by the product between the torque and the engine speed. The increase of the power can be achieved by two ways: by increasing the maximum speed or by increasing the torque. The speed increase is limited by the mechanical strength of the moving parts, so this solution is not sustainable. Increasing the torque can be done in two ways: by increasing the engine displacement or by turbocharging of the engine. Increasing the engine displacement results in increased engine mass, increased fuel consumption and pollutant emissions. The turbocharger causes the mass of the fuel mixture in the cylinder to increase, respectively increasing the engine power. In conclusion, to increase the power of an internal combustion engine, the mass of the engine and / or the speed of the crankshaft must be increased. Taking into account of these, were analyzed the technical and functional characteristics for several types of internal combustion engines. The parameters analyzed in this study were: the engine power, the engine speed, the engine torque, the engine displacement, mass of the engine, fuel consumption, ratio of engine mass to engine power, ratio of engine speed to engine power. The conclusions and recommendations resulting from this study refer to the optimal use of internal combustion engines in different fields of activity.
internal combustion engine, power, speed, torque, mass, fuel consumption
Soil Sciences
Presentation: oral