Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study tests new muffler technology for auto industry

19.11.2003


Ohio A study of muffler technology at Ohio State University is giving automakers new options for designing quieter cars.

Engineers here have tested a promising new muffler design that utilizes glass fiber, and are developing the computational tools manufacturers will need to optimize the design.

The new design can often silence auto noise just as well as a typical muffler, but it can be lighter, less prone to corrosion, and help engines work more efficiently.



Ahmet Selamet, professor of mechanical engineering and head of the Flow, Engine, and Acoustics Research Laboratories at Ohio State’s Center for Automotive Research and Intelligent Transportation, gave an overview of his recent work November 19 at the American Society of Mechanical Engineers meeting in Washington, DC.

For more than a decade, Selamet and his colleagues have developed computer-based tools and specialized equipment for improving auto exhaust systems. The challenge, he said, is to control noise and exhaust emissions without blocking the flow of exhaust gases from the engine.

The ultimate silencing device is a potato in the tailpipe, Selamet said with a laugh. But of course engines need to breathe to work properly, so we have to be more creative.

Owens Corning recently asked Selamet to test and redesign a European muffler system that contained glass fiber stuffing. His task was to reduce the design complexity, reduce the weight of the system, and improve engine performance -- while at the same time maintaining or even improving overall exhaust noise levels.

Fiber-filled mufflers have been used in European and Japanese cars for years, Selamet explained, but not much elsewhere. In North America, most mufflers work by using metal chambers and baffles to slow the flow of air or redirect it.

But chambers and baffles can restrict the flow of the exhaust gases, increasing what is known as back pressure. When that happens, some of an engines work is wasted pushing the burned gases through the exhaust system, instead of pushing the car forward. With a simpler interior design, a fiber-filled muffler could cause less back pressure and make engines more efficient.

Historically, though, the North American auto industry has been skeptical about using filling in mufflers, and rightly so, Selamet said. Early European designs used basalt wool, which is packed in short fibers. Studies have shown that over time, these short fibers break up and blow out in the exhaust stream.

Then the car gets louder, Selamet said.

Continuous glass fiber could offer a better alternative to wool, he said, because the fiber strands are too long and intertwined to be blown out of the muffler. According to Owens Corning, a gumball-sized glass marble that is spun into a strand of continuous fiber for exhaust applications can measure 18 miles long, with a diameter one quarter that of a human hair.

Selamet also said that glass fiber can better withstand the high temperatures produced in modern exhaust systems, and potentially even insulate the car from that heat.

Since automakers such as Volvo are using glass fiber in mufflers sold in Europe, Selamet had an opportunity to test the design. Owens Corning supplied him with new and used Volvo mufflers, as well as loose fiber samples. The used mufflers came from cars that had been driven 100,000 miles.

In tests, Selamet and his colleagues found that the fiber reduced engine noise substantially. For example, at the mid-range frequency of 1500 Hertz, the new design reduced the noise by 40 decibels. Thats significantly higher than the typical muffler rating of 30 decibels or lower.

The mufflers used for 100,000 miles performed just as well as the new.

The Ohio State engineers developed a computerized tool that manufacturers can use in optimizing the design of a fiber-filled mufflers for different car models.

A major parts maker has also expressed interest in using the fibers in an automotive intake system, where, as Selamet pointed out, automakers have a big opportunity to quiet engine noise.

One of the most powerful noise-reducers in the intake system of a car is the air cleaner box, he said, referring to the housing that contains filter to clean debris from the outside air before feeding it to the engine.


#

Contact: Ahmet Selamet, (614) 292-4143; Selamet.1@osu.edu
Written by Pam Frost Gorder, (614) 292-9475; Gorder.1@osu.edu

Pam Frost Gorder | Ohio State University
Further information:
http://researchnews.osu.edu/archive/fibrmufl.htm

More articles from Transportation and Logistics:

nachricht Tool helps cities to plan electric bus routes, and calculate the benefits
09.01.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht Realistic training for extreme flight conditions
28.12.2016 | Technical University of Munich (TUM)

All articles from Transportation and Logistics >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>