The Swiss company Antrova has presented a further development of the Comprex pressure wave charger. Supported by an electric motor, it has now been tested in a natural gas engine.
The Comprex charger uses pressure waves from the exhaust gas for supercharging.
Antrova AG
Engineers at Antrova AG (Stein am Rhein, Germany) have further developed the Comprex pressure wave charger. Like the exhaust gas turbocharger, the pressure wave charger is an energy exchanger. It uses the residual expansion energy unused by the combustion engine in a thermodynamic process to compress charge air and transport it to the engine. The technology was used in passenger car diesel engines from Opel and Mazda, among others, in the 1980s. However, there were problems with the buildup of the pressure wave process during cold starts. Also, temperature-related effects during load changes led to emission and efficiency problems.
The Comprex 2.0 now has a new design of what is known as the cell rotor, and it is also supported by an electric motor. This should completely solve the previous difficulties with temperature changes. In collaboration with a commercial vehicle manufacturer and the producer of the supercharger, Empa researchers have now built a natural gas engine with a Comprex 2.0 supercharger. According to the study, the engine delivers an enormously high torque even from idling speed. In combination with so-called Miller operation and an adjustment of the gear ratio, consumption is reduced. In addition, according to the researchers, the catalytic converter warms up six times faster than with the turbocharged engine, which ensures better exhaust gas values. Another advantage is the high engine braking effect of the pressure wave charger.