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Increasing the efficiency of an internal combustion engine is possible thanks to the use of an extended expansion stroke relative to the suction stroke. This solution was first patented by James Atkinson in the construction of an internal combustion engine in the XIX century. The article presents a solution using the principle of extended expansion stroke. In the design of Szymkowiak's proprietary engine, a conceptual crank-piston system was used with additional elements enabling the Atkinson cycle to be obtained. A 3D model was created based on which forces acting in the system were tested. The generated piston path profile allowed to characterize its movement. A mobile mesh of the combustion chamber was created, thanks to this a detailed CFD simulation was performed in the AVL Fire software. An important criterion was the assumption of adiabatic characteristics of processes during the combustion.

The paper describes the measurement of PM emission from an excavator engine under actual operating conditions. The exploration of the relations between the engine operating parameters and its emissions requires measurements under actual conditions of engine operation. The specificity of the emission measurements, PM in particular, requires technologically advanced measuring devices. The situation gets even more complicated when, beside the PM mass. The particle size distribution and number (PN) also need to be measured. An important technical issue is the difficulty in fitting the measurement equipment in/on the vehicle in operation (e.g. excavator), which is why the presented investigations were carried out in a laboratory under simulated operation. The laboratory technicians applied load to the engines through the excavator hydraulic system.