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The utilization of exhaust gas recirculation (EGR) is a fundamental approach to the reduction in the nitrogen oxide emissions from engines that operate on lean fuel mixtures, particularly diesel engines. However, the return of a fraction of the exhaust gases back into the engine's intake manifold, is likely to produce an adverse effect on the engine performance by degrading its power and economic indicators. To address this issue, therefore, the paper develops a more practical approach to optimize the diesel engine exhaust gas recirculation flow rate in order to reduce the nitrogen oxide content with minimum loss of power. A specific optimality criterion was established, and a three-input-factor experiment was successfully conducted. The optimization problem was solved allowing for the achievement of a minimum NOх content under all operating conditions in the selected mode of the engine. [ABSTRACT FROM AUTHOR]

Extensive research is being conducted on a global scale to explore the possibilities and prospects for the practical realization of the operation of internal combustion engines with different types of fuels. The advantages, disadvantages, peculiarities of the work process when using alternative fuels are carefully examined and fully discussed. The aim of the scientific research is to develop methods, find constructive solutions and propose the necessary modifications for the rebuilding of the engines of the existing cars. Clarified, additionally, is the impact of different fuels on the toxicity, power and economic indicators of internal combustion engines. [ABSTRACT FROM AUTHOR]

The present paper determines the influence of the permissible injection advance angle on the economic and ecological indicators of automotive diesel engines in operation. A series of bench motor tests was performed on the engine to examine a case of altered injection advance angle under the conditions of constant injected fuel quantity and constant speed, and, on that account, a constant air-fuel ratio. Many engine parameters were measured during the test. Based on the results obtained for each mode of operation, the indicator and effective engine parameters have been calculated, as well as those characterizing the process of combustion. The development of the combustion process is illustrated by the diagrams of the instantaneous in-cylinder pressure, the rate of active heat release and the instantaneous amount of active heat released in two characteristic modes. [ABSTRACT FROM AUTHOR]