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Researchers from Michigan State University have been awarded $2.5 million from the Department of Energy’s ARPA-E program (earlier post) to complete its prototype development of a new gasoline-fueled wave disc engine and electricity generator that promises to be five times more efficient than traditional auto engines in electricity production, 20% lighter, and 30% cheaper to manufacture.
The wave disc engine, a new implementation of wave rotor technology, was earlier developed by the Michigan State group in collaboration with researchers from the Warsaw Institute of Technology. About the size of a large cooking pot, the novel, hyper-efficient engine could replace current engine/generator technologies for plug-in hybrid electric vehicles.
The award will allow a team of MSU engineers and scientists, led by Norbert Müller, an associate professor of mechanical engineering, to begin working toward producing a vehicle-size wave disc engine/generator during the next two years, building on existing modeling, analysis and lab experimentation they have already completed.
Our goal is to enable hyper-efficient hybrid vehicles to meet consumer needs for a 500-mile driving range, lower vehicle prices, full-size utility, improved highway performance and very low operating costs. The WDG also can reduce carbon dioxide emissions by as much as 95 percent in comparison to modern internal combustion vehicle engines.
—Norbert Müller
More on the Wave Disc technology
http://www.egr.msu.edu/mueller/NMReferences/PiechnaAkbariIancuMuellerIMECE2004-59022.pdf">RADIAL-FLOW WAVE ROTOR CONCEPTS, UNCONVENTIONAL DESIGNS AND APPLICATIONS
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WAVE ROTOR APPLICATIONS
As a combined expansion and compression device, the
wave rotor can be used as a supercharging device for IC
engines, a topping component for gas turbines, or in
refrigeration cycles. In advanced configurations, the high
energy fluid may be generated by combustion occurring
internally in the wave rotor channels allowing extremely short
residence times at high temperature, hence potentially reducing
emissions. A condensing wave rotor may be viewed as a
similarly advanced configuration that enhances the
performance of refrigeration cycles. Recently, wave rotor
technology has been envisioned to enhance the performance of
ultra-micro gas turbines manufactured using today’s and future
microfabrication technologies <7, 8>.
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Car Engine Supercharging
Wave rotors have been commercially used for IC engines
as a replacement for conventional supercharges or
turbochargers. Brown Boveri Company (BBC), later Asea
Brown Boveri (ABB) and now Alston, in Switzerland has a
long history in wave rotor technology. As reported by Meyer
<9>, the first successful wave rotor was tested in the beginning
of 1940s as a topping stage for a locomotive gas turbine engine
based on patents by Claude Seippel <38-41>. The first wave
rotor was not used commercially, mainly because of its
inefficient design and crude integration <42>. Later, BBC
decided to concentrate on the development of pressure wave
superchargers for diesel engines, due to their greater payoff
compared to other applications <12>. By 1987, the first wide
application of the Comprex® in passenger cars occurred in the
Mazda 626 Capella <5, 43>. Since then, ABB’s Comprex®
pressure wave supercharger has been commercialized for
several passenger car and heavy diesel engines. The Comprex®
has also tested successfully on vehicles such as Mercedes-Benz
diesel car <6>, Peugeot, and Ferrari <12>. The main advantage of
the Comprex® compared to a conventional turbocharger is its
rapid response to changes in engine operating conditions.
Furthermore, as the efficiency of the Comprex® is independent
of scale, its light weight and compact size make this device
attractive for supercharging small engines (below about 75 kW
or 100 hp) <44, 45>.
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WAVE ROTOR MACHINES
Wave rotor machinery represents a promising technology
that can enhance cycle power and efficiency, plus possibly
reduce the overall size, weight and cost. It allows a higher cycle
peak temperature without need for a cooling system.
Furthermore, the rotational speed of a wave rotor is low
compared with turbomachines. This results in low material
stresses, which may allow for higher material temperatures or
the use of less expensive materials.
The essential feature of a wave rotor is an array of
channels that is arranged around a rotational axis. The channels
may be axial, radial or oblique to the axis. They may be straight
for simplicity or curved in more advanced designs. Likewise,
the cross-sectional area and form of the channels could be
constant in simpler designs and may be varied in advanced
configurations. The channels are incorporated in a drum, disc or
a cone, that usually rotates between two stationary end plates as
shown in Fig. 1 for an axial configuration. The end plates have
ports that direct flow into and out of the channels and connect
the wave rotor through manifolds to the external continuous
flow process.
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The rotating parts may be gear or belt driven or preferably
direct driven by an electrical motor. The power required to keep
them at correctly designed speed is negligible <3, 4>. It only
needs to overcome rotor windage and friction in the bearings
and contact sealing if used. Alternatively, rotors can be made
self-driving. This configuration, known as the “free-running
rotor”, can drive itself by using the momentum of the flow to
rotate the rotor <5, 6>.
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