Car Exhaust and Emissions

This section can help you keep your exhaust system working properly. Learn how mufflers, catalytic converters and oxygen sensors work.

More Auto Topics to Explore

What makes certain car accessories unsafe (or even illegal)?

Modern Cars Are Kind of Boring. Why Is That?

Can car companies let known defects go without a recall?

Do car interiors turn toxic in the summer?

Making a Car Last for 300,000 Miles Is Totally Possible — Here's How

Are cars designed to fail at a certain point?

How long do engine valves last?

You Can't Take Your Fancy Self-Driving Car Out of the City, Yet

The GM Car That Has No Steering Wheel or Pedals

Will Autonomous Vehicles Be Able to Break the Speed Limit?

Do red cars get pulled over more often for speeding?

Do red cars cost more to insure?

Are extended car warranties worth it?

How Do I Get Rid of a Dead Animal Smell in My Car?

5 Signs Your Engine Is Losing Power

Should I replace or repair my car?

How Gas Compression-ignition Engines Work

Did cars ever have external combustion engines?

How does engine placement affect handling?

10 Cold-weather Motorcycle Accessories

Is all motorcycle apparel made of leather?

What motorcycle accessories will help me stay cool?

10 Car Features We Wish Came Standard

How Laser-powered Headlights Work

How Air-Conditioned Seats Work

How to Avoid a 'Hurricane Car'

6 Automotive Parts You Can Easily Recycle

Get Money For Your Old Car Batteries

How does vertical acceleration work?

Gas-powered vs. Electric Cars: Which Is Faster?

Are manual transmissions really faster than automatics?

What are manual transmission synchronizers?

The Dirty Truth About How Often You Need Your Oil Changed

Do you really need to pay for that 30,000-mile service?

Why Do Tires Blow Out More in Summer?

Winter Tires Really Do Make a Difference in the White Stuff

Why Carmakers Are Ditching the Spare Tire

Can your car tell you when the light's about to change?

How the Open Automotive Alliance Works

How Paintless Dent Removal Works

Learn More

Dieselgate and the Volkswagen Cartel

Have the right Volkswagen execs paid for lying to the public about their car's environmental standards and emissions?

By Diana Brown May 1, 2018 Under the Hood / Exhaust & Emissions

Diesel Isn't Always a Worse Polluter Than Gasoline

Whether diesel- or gasoline-powered cars spit out more toxins depends on the pollutant measured, a new study says.

By Shelley Danzy Aug 1, 2017 Under the Hood / Exhaust & Emissions

In a truck pull competition, excessive clouds of diesel smoke are a byproduct of the truck's functionality. But coal rollers have taken this idea from the county fair to the public roads -- all in the name of making people angry.

By Cherise Threewitt Under the Hood / Exhaust & Emissions

How much air pollution comes from cars?

You see it every time that smoke billows from your car's exhaust pipe, so there's no denying that vehicles are major contributors to air pollution.

By Linda C. Brinson Under the Hood / Exhaust & Emissions

Top 7 Ways to Reduce Your Driving Emissions without Reducing Quality of Life

Here are seven easy ways to reduce your emissions without affecting the quality of your daily commute. Learn more about the top 7 ways to reduce your driving emissions without reducing quality of life.

By Eric J. Leech, Planet Green Under the Hood / Exhaust & Emissions

What can you do to reduce your car's emissions?

To reduce your cars emissions, you can help its catalytic converter work more efficiently by preheating it, or you can inject a urea solution into your exhaust pipe. Learn what you can do to reduce your car's emissions in this article.

By HowStuffWorks.com Contributors Under the Hood / Exhaust & Emissions

Can we make tailpipes that capture CO2?

It seems like a logical answer to the climate crisis: capture the carbon dioxide that our cars emit. Is it that simple? And what do sand and silica have to do with it?

By Josh Clark Under the Hood / Exhaust & Emissions

Why is there a bulge in the exhaust pipe of my dirt bike?

I have a dirt bike and the exhaust pipe has this big bulge in it near the engine. What is the bulge for?

Under the Hood / Exhaust & Emissions

How Mufflers Work

Every car out there has a muffler -- it performs the crucial job of turning thousands of explosions per minute into a quiet purr. Mufflers use some cool technology to dim the roar of an engine. Learn the principles that make it work.

By Karim Nice Under the Hood / Exhaust & Emissions

How Catalytic Converters Work

A catalytic converter is one of the most important parts of a car's emissions control system. It treats the exhaust before it leaves the car and removes a lot of the pollution. Learn how they work.

By Karim Nice & Charles W. Bryant Under the Hood / Exhaust & Emissions

How do I know if my catalytic converter has failed?

Exhaust emissions test check for the absence of a catalytic converter or a malfunctioning one during an emissions inspection. Read on to learn how you can find out if your catalytic converter has failed.

Under the Hood / Exhaust & Emissions

How does the oxygen sensor in a car work?

An oxygen sensor in a car is a very important part of making your engine run smoothly. Learn what it does and what can happen if your oxygen sensor fails.

Under the Hood / Exhaust & Emissions

What is a catalytic converter and how does it work?

If you have a vehicle that needs to be tested for emissions, you might want to check on the condition of your catalytic converter. So what is it and what does it do?

Under the Hood / Exhaust & Emissions