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 Study sets new distance record for medical drone transport
13.09.2017 | Johns Hopkins Medicine

nachricht Researchers 'count cars' -- literally -- to find a better way to control heavy traffic
10.08.2017 | Florida Atlantic University

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: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

More genes are active in high-performance maize

19.01.2018 | Life Sciences

How plants see light

19.01.2018 | Life Sciences

Artificial agent designs quantum experiments

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>