Pressure wave supercharger
From Wikipedia, the free encyclopedia
A pressure wave supercharger is a type of supercharger technology that harnesses the pressure waves produced by an internal combustion engine exhaust gas pulses to compress the intake air. Its automotive use is not widespread but can be found on the RF series diesel engine found in 1988 Mazda Capella, and the Greenpeace SmILE concept car.
[edit] Principle
The process is controlled by a cylindrical cell rotor whose speed is synchronised with the engine crank speed via a belt or chain. Individual cells alternately open and close the exhaust gas and fresh air apertures, when the aperture on the exhaust gas side is reached pressurised exhaust gas flows into the cell and compresses the fresh air there. As the cell rotor continues to rotate and reaches the aperture on the inlet side the compressed air flows to the engine. Before the exhaust gas can flow the aperture is closed again and the exhaust gas column is reflected before entering the engine. The exhaust gas exits at high speed sucking further intake air into the cell behind it repeating the process.
[edit] Advantages
Energy exchange in the pressure-wave supercharger occurs at sound velocity, resulting in good response even at low engine speeds, a common downfall of turbocharged engines. It combines the advantages of mechanical and exhaust gas turbocharging.
