Supercharging the reciprocating piston internal combustion engine is as old as the engine itself. Early on, it was used to improve the high-altitude performance of aircraft engines and later to increase the short-term peak performance in sporty or very expensive automobiles. It took nearly 30 years until it reached economic importance in the form of the ef?ciency-improving exhaust gas turbocharging of slow- and medium-speed diesel engines. It took 30 more years until it entered high-volume automotive engine production, in the form of both mechanically driven displacement compressors and...