The shift from fossil-fueled internal combustion engines to electrically powered vehicles leads to further electrification of many sub-systems. However, in commercial vehicles, systems powered by compressed air will prevail. This leads to a demand for mobile electrically driven air compressors. They require a compact and lightweight design as well as oil-free and high-speed operation. A careful and thorough development process is crucial to meet the challenging requirements. For example, the examination and understanding of the process within the working chambers using indicator measurements are valuable in providing information on key performance indicators (e.g., indicated work, valve behavior and energy efficiency).
In this paper, two topics are presented: First, the fundamental compressor layout of the two-stage four-cylinder reciprocating compressor and its unique characteristics are shown. The unconventional design results in outstanding compactness while ensuring the required mass force balancing and throughput. Second, indicator measurements and specific features of their evaluation are presented. In particular, it is shown how to solve the problem of impaired crank angle detection using logarithmic indicator diagrams.