src: www.engr.colostate.edu
A Rapid compression machine (RCM) is an experimental device used to simulate a single compression stroke of an internal combustion engine. A rapid compression machine can be used for chemical kinetics studies. It is often used as an alternative to a shock tube for understanding specifically low-to-intermediate temperature autoignition chemistry under idealized automotive engine conditions.
Video Rapid compression machine
References
Source of the article : Wikipedia