The paper presents an original design of a single compression machine for combustion study. The principle of operation is based an old concept, utilizing the inertia energy of a flywheel to accelerate the crank mechanism and the attached piston to compress rapidly the combustible mixture in the combustion chamber. A square piston geometry was adopted to allow visualization of the compression and combustion processes in directions perpendicular to the cylinder axis. To avoid the extensive scratching of glass walls by the moving piston, a special multi-action clutch-brake unit was used; this facilitates coupling of the flywheel with the crank mechanism during the single piston stroke and subsequent immediate uncoupling and fast stopping of the piston. The whole operating cycle can be completed within no more than two revolutions of the crankshaft. The design details of the machine, its acceleration characteristics and a sample of the visualized combustion process are presented.

The paper presents a general idea of the acceleration test method and the design, construction and testing of the inertial dynamorneter test rig developed for small, high performance two-stroke engines. The method is universal and can be also used for four-stroke engines but it is especially useful for the two-stroke ones. The testing procedure is described and the advantages of that type of investigation method are pointed out. It has been proved that the reliability of the method is satisfactory. It was also proven that the individual construction of the inertial dynamorneter of good quality can be performed individually and that it can be a very useful investigation tool in engine tuning practice. The point has been stressed that the major advantage of that method is the possibility of the instantaneous measurement of the engine power characteristic during unsteady engine operation (acceleration) where the time for the single run does not exceed ten seconds.

The motion of a ring pack an oil film covering the cylinder liner has been considered. In the paper, equations, a numerical method, algorithm of solution and results of numerical simulations of this phenomena have been presented. The model presented takes into account hydrodynamic, spring and gas forces acting on each ring. The cases of motion with full and partial wetting of ring land have been considered. The influence of engine rotational speed, ring land curvature, oil viscosity on individual rings radial motion and oil film thickness have been analysed. The results of the calculations have been presented in graphical form.

The motion of a ring pack on a thin film covering a cylinder liner has been analysed. In contrast to the previous papers [30], [31], which considered a primary hydrodynamic phenomena (including mixed lubrication), in the present paper an additional degree of freedom of a ring i.e. a twist motion is also taken into account. Equations describing the twist of rings are presented and used in simulation. The twist phenomena of a single ring have been analysed in the past [25]. In this paper, the twist effects of separate rings forming a ring pack are considered. In the pack configuration, the twist of the upstream ring strongly influences the operation of the downstream ring. The phenomenon commonly treated as secondary effect seems to be influencing the ring motion strongly. Differences between results obtained applying and neglecting ring twist motion are analysed and discussed.