The thermal efficiency of a differential stroke engine based on the Atkinson cycle is higher than that of engines with an Otto cycle or Diesel cycle. To fulfill the requirement of the expansion ratio that is greater than the compression ratio in the Atkinson cycle, a mechanism with an inner piston that can provide such a motion control in a differential stroke engine is needed. In order to measure both of the inner piston motion and the cylinder pressure of a differential stroke engine, this thesis is focused on building up a measurement system to inspect the design of a mechanism that achieves the motion needed in a differential stroke engine. To obtain the inner piston motion in a differential stroke engine operated at a speed, the measurement system is equipped with a laser sensor and an angular encoder to identify the difference between the theoretical and experimental results. Also, to inspect the cylinder pressure, a pressure transducer is employed with the test bed so that both of the P-T diagram and P-V diagram can be calculated by using the measured result. To demonstrate the effectiveness of the developed test bed, real experiments are performed. The developed measurement system has proved to be a useful tool during the developing processes of design and manufacture of differential stroke engines.

The diploma thesis deals with mechanism of combustion motor that enables greater expansion ratio then compression ratio. The main advantage of motor mechanism is verified in thesis, which is greater thermal efficiency then compared to conventional diesel motor. Additionally, there are investigation of kinematic variables, force of gas pressure and inertia forces, which operates in different bindings mechanism. The last part deals witch strength of selected parts of the proposed mechanism.

This thesis deals with the design of a spark-ignition internal combustion engine with extended expansion. It explains the principle of extended expansion using the Atkinson or Miller cycle and the possibilities of achieving it. In addition, a design study and engine cycle is carried out. Subsequently, the course of the kinematic quantities and forces in the mechanism is determined. At the end, the strength analysis of the connecting rod of the designed mechanism is performed.