The experimental study of mechanical losses in the modern diesel engine

BACKGROUND: Amid the tightening of the CO₂ emission requirements as well as high level of competition on the commercial truck market, the focus area of the internal combustion engine (ICE) development is as follows: high engine efficiency and fuel economy, minimization of internal losses and engine cycle optimization for all operation modes. Engine performance factors of modern 12–13-liter diesel engines, existing on the global market, are as follows: the minimal specific fuel consumption is 179–182 g/kWh, effective efficiency is 46–48%. Decreasing of mechanical losses is one of the features that made the achievement of such factors possible. The relevant issue for choosing the strategy of mechanical losses decreasing is formation of balance in losses distribution between main ICE groups of components. Moreover, considering the mechanical losses dependence on engine operating speed, engine cycle parameters and engine design features, it is important to determine the pattern of change in mechanical losses.

AIMS: Assessment of mechanical losses of modern diesel engine with high effective efficiency in an experimental way. Formation of mechanical losses balance.

METHODS: The study object is the 6ChN 13/15 inline six-cylinder diesel engine with the operation volume of 11.95 liters. The mechanical losses assessment was performed with the engine, propelled by a dynamometric machine on a testing facility with fully stabilized conditions, with the method of sequential disassemble of main groups of components.

RESULTS: Relevant data of mechanical losses level of the modern diesel engine with the distribution between main groups of components is obtained. Mechanical losses dependence on operation speed, oil and coolant liquid temperatures is formed.

CONCLUSIONS: Practical value of the study lies in assessment of contribution of each group of components in the total friction as well as in assessment of the degree of design and technological development of ICEs. According to the study results, areas of possible improvement of friction for each group of components and engine as a whole will be formed.