How Do Mufflers Work?

Nov 5, 2019

Hey All!

I don't know about you, but It's recently occurred to me that I have no actual idea how mufflers work! 

I mean, I know that they muffle the engine exhaust sound, but how and who developed them are unknowns. 

If you've ever had a hole in your exhaust line in a car, you quickly grow to appreciate the muffling sound of Mufflers! 

One of the product types we've been adding to the website is Pipes.  

Pipes on a bike are similar to mufflers on a car.  

Before you say anything, yes I know they are quite different. But they do work in similar ways! 

So anyway, lets get into a little history of the muffler and learn some stuff! 

So first off, what is a muffler and how does it work?  

According to Everipedia; "A muffler (silencer in British English) is a device for reducing the noise emitted by the exhaust of an internal combustion engine. This noise deadening device is especially one forming part of the exhaust system of an automotive vehicle."  

There is an upside and downside to mufflers. Their main purpose is to muffle the sound of the engine. They use different ways to do this based on the muffler, manufacturer and usage, and for the most part, they seem to be good at that. 

The downside is that the exhaust has to follow the same pathways as the sound that's getting muffled, which creates a back-pressure which can lower the efficiency of the engine.  

There have been a number of designs implemented to counteract the sound including a series of passages and chambers lined with roving fiberglass insulation and/or resonating chambers harmonically tuned to cause destructive interference, wherein opposite sound waves cancel each other out. 

It doesn't take a scientist to understand how the more twists and turns the exhaust has to go through, the slower it moves through the muffler. 

As technology improves, so does the ability for both car and bike manufacturers and aftermarket companies to reduce the amount of back-pressure without losing the sound muffling effect.  

So let's jump back into the 1800's and see where the idea of the muffler first originated! 

Milton Othello Reeves was an American businessman/ inventor who developed a variable speed transmission and also a double muffler. He filed a patent for the muffler in 1897. His original patent, #582485, was for use on a motorcycle of his own design.  

He made a name for himself with the development of the variable speed transmission and made a good living off it, unfortunately, he wasn't as profitable when he started developing cars. In fact, one car that he's knows for is the Octo-Auto that used an existing body, reworked to have 8 wheels! It was such an unwieldy beast that in 2011, Hemmings Motor News featured it as an April Fools' Day article on its website titled World celebrates the centennial of the Octo-Auto  

After the turn of the century, a Frenchman named Eugene Houdry  developed a catalytic process for doubling the amount of usable oil from crude oil. He produced high-grade gasoline from low-grade fuel.  

His process was used by the French in World War 2 to produce higher quality fuel for their airplanes, and soon thereafter the United States started using the same process.  

After the war, he turned his attention to reducing Carbon output from the vehicles of the time. It turns out that the muffler alone wasn't enough to keep the air clean, so Houdry developed the first Catalytic Converter. In 1962, the year he died, Houdry filed a patent for the catalytic converter. The converter reduced carbon dioxide and hydrocarbon emissions released into the atmosphere by vehicles. It has since become a standard for automobiles around the world! 

"So what about the motorcycle Pipes and Silencers?" you may ask. 

Well, it looks like the motorcycle itself was an idea that popped up all over Europe around the same time. The idea was a direct result of the implementation of motors onto bicycles. The standard two wheeled bicycle had been a staple for many years prior to the first engine, so once engines became small enough to build onto the bike frame, the idea took off! 

People argue about who the first true creator of the motorcycle was, and most people seem to fall on the side of Gottlieb Daimler, who patented a design in 1885 that is generally considered to be the first true motorcycle with a gas powered engine.  

However, there are others who claim that Sylvester Roper built the first true motorcycle in 1867. The engine was powered by steam, which is the defining difference.  

It appears that the design of the pipes and silencers on motorcycles were adapted from the mufflers that were already available for automobiles. While the patents I already mentioned were filed early on, the pipes we know today are apparently just the natural progression of exhaust technology. You can find the history of the first motorcycles available here:  

The technology of the gasoline powered vehicle is truly fascinating and awe-inspiring! 

It seems that the 1800's were the time of ultimate invention with so many different designs and creations popping up all over the world. It's incredible to look back on the history with the viewpoint from the current level of technology we all take for granted today.  

I hope you enjoyed this little trip down History with me.  

Have fun out there 

See ya soon! 

Image by Capri23auto from Pixabay