Pressure wave supercharger
Encyclopedia
A pressure wave supercharger (also known as a wave rotor) 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; the most widely used example is the Comprex, developed by Brown Boveri. Ferrari
tested such a device during the development of the 126C
Formula One
car. The system did not lend itself to as tidy an installation as the alternative twin-turbocharger layout, and the car was never raced in this form. A more successful application was in the RF series diesel engine
found in the 1988 Mazda 626 Capella
; ultimately 150,000 Mazda diesel cars were fitted with a Comprex supercharger. Other users included Peugeot
and Mercedes-Benz
. The Greenpeace
SmILE
concept car uses a Hyprex pressure wave supercharger developed by the Swiss company Wenko AG. NASA
uses wave rotors in experiments attempting to increase gas turbine
efficiency. The wave rotor is placed between the compressor, combustor and turbine sections in order to extract more energy from the combustion process.
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.
Supercharger
A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
technology that harnesses the pressure waves produced by an internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
exhaust gas
Exhaust gas
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline/petrol, diesel fuel, fuel oil or coal. According to the type of engine, it is discharged into the atmosphere through an exhaust pipe, flue gas stack or propelling nozzle.It often disperses...
pulses to compress the intake air. Its automotive use is not widespread; the most widely used example is the Comprex, developed by Brown Boveri. Ferrari
Ferrari
Ferrari S.p.A. is an Italian sports car manufacturer based in Maranello, Italy. Founded by Enzo Ferrari in 1929, as Scuderia Ferrari, the company sponsored drivers and manufactured race cars before moving into production of street-legal vehicles as Ferrari S.p.A. in 1947...
tested such a device during the development of the 126C
Ferrari 126 C
The Ferrari 126C was the car with which Ferrari raced in the 1981 Formula One season. The team's first attempt at a turbo engined Formula 1 car, it was designed by Mauro Forghieri and Harvey Postlethwaite and used between the 1981 and 1984 seasons....
Formula One
Formula One
Formula One, also known as Formula 1 or F1 and referred to officially as the FIA Formula One World Championship, is the highest class of single seater auto racing sanctioned by the Fédération Internationale de l'Automobile . The "formula" designation in the name refers to a set of rules with which...
car. The system did not lend itself to as tidy an installation as the alternative twin-turbocharger layout, and the car was never raced in this form. A more successful application was in the RF series diesel engine
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
found in the 1988 Mazda 626 Capella
Mazda Capella
The second generation rear-wheel drive Capella was available between 1978 and 1982, in both sedan and coupe forms. It was known on export markets as the Mazda 626, with the exception of the United Kingdom, where it was called the Mazda Montrose, the name was changed to honour the local Mazda...
; ultimately 150,000 Mazda diesel cars were fitted with a Comprex supercharger. Other users included Peugeot
Peugeot
Peugeot is a major French car brand, part of PSA Peugeot Citroën, the second largest carmaker based in Europe.The family business that precedes the current Peugeot company was founded in 1810, and manufactured coffee mills and bicycles. On 20 November 1858, Emile Peugeot applied for the lion...
and Mercedes-Benz
Mercedes-Benz
Mercedes-Benz is a German manufacturer of automobiles, buses, coaches, and trucks. Mercedes-Benz is a division of its parent company, Daimler AG...
. The Greenpeace
Greenpeace
Greenpeace is a non-governmental environmental organization with offices in over forty countries and with an international coordinating body in Amsterdam, The Netherlands...
SmILE
SmILE
SmILE is a showcase car designed for Greenpeace in 1996 to demonstrate how fuel efficient a car can be. The name stands for "Small, Intelligent, Light, Efficient'...
concept car uses a Hyprex pressure wave supercharger developed by the Swiss company Wenko AG. NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
uses wave rotors in experiments attempting to increase gas turbine
Gas turbine
A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in-between....
efficiency. The wave rotor is placed between the compressor, combustor and turbine sections in order to extract more energy from the combustion process.
Principle
The process is controlled by a cylindrical cell rotor whose speed is synchronised with the engine crankshaftCrankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...
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.
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 supercharging.Control system
A control system, to optimise performance, was patented in 1986 by Hachiro Aoki for Diesel Kiki Co. Ltd., Tokyo, Japan - United States Patent 4563997.See also
- Exhaust pulse pressure chargingExhaust pulse pressure chargingExhaust pulse pressure charging is a system for supercharging two-stroke diesel engines of the loop-scavenge type. Loop-scavenge engines cannot be pressure-charged in the same way as uniflow engines or four-stroke engines because the inlet and exhaust ports are open at the same time.-Overview:The...
- Inertial supercharging effectInertial supercharging effectInertial supercharging effect is the result of incoming fuel/air charge developing momentum greater than intake stroke would generate alone. It is achieved by a combination of head/port configuration, and cam profile/valve timing....
- Kadenacy effectKadenacy effectThe Kadenacy effect is an effect of pressure-waves in gases. It is named after Michel Kadenacy who obtained a French patent for an engine utilizing the effect in 1933. There are also European and US patents...