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A pressure wave supercharger (also known as a wave rotor) is a type of
including details of Comprex supercharger Valmet Tractors of Finland were one of the first to use the device when they fitted it to the 411CX engine which powered their 1203 model of 1980. Although it provided a useful increase in performance it was considered too expensive to be incorporated into later models. Ferrari tested such a device during the development of the 126C
The process is controlled by a cylindrical cell rotor driven by the engine crankshaft 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, pressurized exhaust gas flows into the cell and compresses the fresh air there (Diagram Stage 2). As the cell rotor continues to rotate and reaches the aperture on the inlet side, the compressed air flows to the engine (3). Before the exhaust gas can flow, the aperture is closed again and the exhaust gas column is reflected before entering the engine (4). The exhaust gas exits at high speed, sucking further intake air into the cell behind it, repeating the process (1).
Technical Description
Wenko AG's website on the Pressure wave supercharger
Diagram of operation simplified
{{DEFAULTSORT:Pressure Wave Supercharger Superchargers Exhaust systems
A pressure wave supercharger (also known as a wave rotor) is a type of supercharger
In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement.
The current categorisation is that a supercharger is a form of forced indu ...
technology that harnesses the pressure waves produced by an internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal co ...
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, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through a ...
pulses to compress the intake air. Its automotive use is not widespread; the most widely used example is the ''Comprex'', developed by Brown Boveri.A Review of Wave Rotor Technology and its Applicationsincluding details of Comprex supercharger Valmet Tractors of Finland were one of the first to use the device when they fitted it to the 411CX engine which powered their 1203 model of 1980. Although it provided a useful increase in performance it was considered too expensive to be incorporated into later models. Ferrari tested such a device during the development of the 126C
Formula One
Formula One (also known as Formula 1 or F1) is the highest class of international racing for open-wheel single-seater formula racing cars sanctioned by the Fédération Internationale de l'Automobile (FIA). The World Drivers' Championship ...
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
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-ca ...
found in the 1988 Mazda 626 Capella; ultimately 150,000 Mazda diesel cars were fitted with a Comprex supercharger. Other users included Peugeot
Peugeot (, , ) is a French brand of automobiles owned by Stellantis.
The family business that preceded the current Peugeot companies was founded in 1810, with a steel foundry that soon started making hand tools and kitchen equipment, and then ...
, Opel
Opel Automobile GmbH (), usually shortened to Opel, is a German automobile manufacturer which has been a subsidiary of Stellantis since 16 January 2021. It was owned by the American automaker General Motors from 1929 until 2017 and the PSA ...
and Mercedes-Benz
Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquarter ...
.
The Greenpeace
Greenpeace is an independent global campaigning network, founded in Canada in 1971 by Irving Stowe and Dorothy Stowe, immigrant environmental activists from the United States. Greenpeace states its goal is to "ensure the ability of the Earth ...
SmILE
A smile is a facial expression formed primarily by flexing the muscles at the sides of the mouth. Some smiles include a contraction of the muscles at the corner of the eyes, an action known as a Duchenne smile.
Among humans, a smile expresses d ...
concept car uses a ''Hyprex'' pressure wave supercharger developed by the Swiss company Wenko AG. NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeedi ...
uses wave rotors in experiments attempting to increase gas turbine
A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directio ...
efficiency. The wave rotor is placed between the compressor, combustor, and turbine sections to extract more energy from the combustion process.
Principle
The process is controlled by a cylindrical cell rotor driven by the engine crankshaft 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, pressurized exhaust gas flows into the cell and compresses the fresh air there (Diagram Stage 2). As the cell rotor continues to rotate and reaches the aperture on the inlet side, the compressed air flows to the engine (3). Before the exhaust gas can flow, the aperture is closed again and the exhaust gas column is reflected before entering the engine (4). The exhaust gas exits at high speed, sucking further intake air into the cell behind it, repeating the process (1).
Advantages
Energy exchange in the pressure-wave supercharger occurs at sonic 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, offering ample torque at lower engine speeds.Disadvantages
The Comprex system has two shortcomings. One, that the exhaust gases intermingle with the fresh air needed for combustion, leading to some recirculation of burnt gas. Secondly, this co-mingling also raises the temperature of the intake gas. Both of these are much less of a problem in a diesel than a petrol engine, hence the Comprex's rarity in petrol-engined applications.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 charging * Inertial supercharging effect * Kadenacy effectReferences
External links
Technical Description
Wenko AG's website on the Pressure wave supercharger
Diagram of operation simplified
{{DEFAULTSORT:Pressure Wave Supercharger Superchargers Exhaust systems