How do engines work? (Road Trip pt. 1)

On the first leg of our road trip, we’re exploring the history of engines and how they work, with a little help from Car Talk’s Ray Magliozzi. The fundamentals of the internal combustion engine, haven’t really changed since it was first invented in the 1800s. How do tiny explosions power our cars? And how did gas-powered cars come to dominate over electric and steam-powered engines?

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The engines used in most cars today are called internal combustion engines, but when they were first invented they were called “exploding engines” by some. That’s because your car is powered by lots of tiny, controlled explosions happening inside its engine.

For most cars, that’s at least 6000 explosions PER MINUTE when you’re driving down the highway. An explosion of explosions!

Here’s how it works: When a fuel like gasoline is mixed with air, and then exposed to a bit of heat — boom! That’s called combustion. This reaction produces exhaust and heat.

Exhaust is mostly made up of gases so when it’s heated up, it expands. This expanding gas exerts a pressure, pushing on the things around it. In this case, the gas pushes on sliding parts of the engine called the pistons, which are metal rods that fit neatly in metal tubes.

When gases push on them, the pistons move up and down inside their tubes, sort of like your legs move up and down when you pedal a bike. The moving pistons, turn the crankshaft, which makes the wheels turn.

How A Car Engine Works (animated)

From Visually.

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Photos: Early automobiles

Karl Benz (in light suit) on a trip with his family with one of his first cars, which was built in 1893 and powered by a single cylinder, 3 h.p. engine. His friend Theodor von Liebig is in the Viktoria. (Photo by Hulton Archive/Getty Images)

14th November 1896: Mr Walter C Busey’s electric landau on the London to Brighton motor car run. (Photo by Hulton Archive/Getty Images)

Circa 1899: A steam car named ‘The Lifu’. (Photo by Hulton Archive/Getty Images)

Essen, GERMANY: Bill and Rachel Rich from Great Britain drive their steam powered vintage Stanley constructed in 1908, 04 April 2006 on the fair grounds in Essen, western Germany, in preparation of the “Techno-Classica” fair. The show, running from 06 to 09 April, is a forum of the vintage car industry, the classic car dealer network and the classic club scene. (VOLKER HARTMANN/AFP/Getty Images)

circa 1910: President Theodore Roosevelt in an American Government 30-horsepower White Steam Car. (Photo by Hulton Archive/Getty Images)

An Anwell Johnson electric car at the Electrical Vehicle Parade in Kingston upon Thames, 19th June 1915. (Photo by Topical Press Agency/Hulton Archive/Getty Images)

20th October 1920: Friends going for a ride in a Model T Ford stop to pick up another passenger. (Photo by Three Lions/Getty Images)