Influence of gas-dynamic processes on motor efficiency and durability

Abstract

Equipment generating or consuming energy must satisfy ever-increasing efficiency and environmental requirements. Currently, researchers at the Institute of Energy-Efficient Technologies at Tupolev Kazan State Technical University are endeavoring to improve the low efficiency of internal combustion engines. The operation of internal-combustion engines is characterized by mechanical, gas-dynamic, and thermophysical losses. Mechanical losses are regarded as the most significant. Research is underway to determine the influence of other factors on the performance and environmental impact of internal combustion engines. The design of such engines is growing ever more complex; new materials are being employed; more stringent requirements are imposed on the fuel and oil; the operational properties are boosted; and the operating conditions are optimized. Nevertheless, the efficiency remains very low. Thus, it is 0.42 for the KAMAZ engine. The efficiency declines with continuing operation of the engine, reaching impractical values. Analysis of the gas-dynamic processes in the working chamber of the engine adjacent to the piston, close to the seal with the cylinder, indicates that the key to increasing the efficiency may be fundamental modification of the piston seal. Poor sealing between the piston and cylinder, which increases the leakage of working gases from the combustion chamber to the housing is compensated by high piston speeds, i.e., increasing the speed of the shaft. In the design of military and sporting equipment, where performance is a priority, the shaft speed may certainly be increased and other methods of boosting engine operation may be applied, without thinking of fuel consumption, resources, and other economic characteristics. However, in developing mass-produced engines for the auto industry and also powerful or superpowerful diesel engines, this approach is neither expedient nor promising. Gas-dynamic analysis of engine operation shows that the design of the seal between the piston and the cylinder in internal-combustion engines, in particular,