Understanding Auto Parts

Man Working on Engine Auto Parts
Looking at all the auto parts can be overwhelming which is why we've broken them down by type so you can learn how each work. Reza Estakhrian / Getty Images
Key Takeaways
  • Various key components of a car include engine systems, power trains and braking systems, each component contributing to a car's operation.
  • Different engine types including diesel, Hemi and rotary engines, along with other systems like superchargers and turbochargers that enhance engine performance.
  • The mechanisms behind manual and automatic transmissions, clutches and other crucial components play different roles in vehicle efficiency and safety.

The basic idea of a car is pretty simple — turn wheels to pull you down the road. But, as illustrated by the hundreds of individual parts for sale at your local Pep Boys, AutoZone or Napa Auto Parts, it actually takes a lot of machinery to make cars work.

If you're trying to figure out what all the parts in your car do, HowStuffWorks AutoStuff is the place for you. Here's a collection of our key car part articles.



Engine System

How Car Engines Work

It's the reason you can put the pedal to the metal and go from zero to 60 in about 8 seconds. The car engine is a piece of engineering genius and one of the most amazing machines we use on a daily basis. Learn how the four-stroke internal combustion engine works.


How Diesel Engines Work

Ever wonder what the difference is between a gasoline engine and a diesel engine? Diesels are more efficient and cheaper to run than gasoline engines. Instead of using carburetion or port fuel injection, diesel engines use direct fuel injection. Find out what else makes diesel engines different!

How Hemi Engines Work

The HEMI engine has an awesome design and great performance, and it's pretty unique in operation. With the revitalization of the HEMI in the 2003 Dodge trucks, industry and consumer attention is once again on this interesting configuration. Check out how the HEMI works and see what makes it different from the typical engine design.

How Rotary Engines Work

A rotary engine is an internal combustion engine, but it's not like the one in most cars. Also called a Wankel engine, this type of engine performs intake, compression, combustion and exhaust in a different part of the housing. Learn about the unique rotary setup and how it compares performance-wise to a piston engine.

How Radial Engines Work

Radial engines reached their zenith during WWII. But today they are not that common. One place where you can still see the radial engine's influence is in the two-cylinder engine of a Harley-Davidson motorcycle. This remarkable engine can be thought of, in a way, as two pistons from a radial engine. Find out about radial engines.

How Quasiturbine Engines Work

The quasiturbine engine takes the Wankel concept and improves on it: Instead of three combustion chambers, it has four, and the setup of a quasiturbine allows for continual combustion. That means greater efficiency than any other engine in its class. Learn about the quasiturbine and why it might be the most promising internal combustion engine yet.

How Camshafts Work

The camshaft has a huge effect on engine performance. It helps let the air/fuel mixture into the engine and get the exhaust out. Learn all about the camshaft and how a new one can radically change an engine's behavior.

How Superchargers Work

Since the invention of the internal combustion engine, automotive engineers, speed junkies and race car designers have been searching for ways to boost its power. One way is by installing a supercharger, which forces more air into the combustion chamber. Learn how superchargers can make an engine more efficient.

How Turbochargers Work

When people talk about race cars, or high-performance sports cars, the topic of turbochargers almost always comes up. Turbochargers use some very cool technology to make an engine more powerful, but the concept is really quite simple. Find out how turbos increase the speed.

How Fuel Injection Systems Work

The last carburetor-equipped car came off the assembly line in 1990. Since then, fuel injectors have been the primary means of getting gasoline into the engine cylinder so it can combust and you can drive. Find out how fuel-injection systems work.


Power Train

How Manual Transmissions Work

If you drive a stick-shift car, then you may have a few questions floating around in your head. Have you ever wondered, "What would happen if I were to accidentally shift into reverse while I am speeding down the freeway? Would the entire transmission explode?" Find out all about manual transmissions.


How Automatic Transmissions Work

Automatic transmissions take the work out of shifting. A truly amazing mechanical system, the automatic transmission in a car accomplishes everything a manual transmission does, but it does it with one set of gears. Learn how the whole setup works.

How Clutches Work

You probably know that any car with a manual transmission has a clutch -- it connects and disconnects the engine and transmission. But did you know that automatics have clutches, too? Learn how the clutch in your car works, and find out about some interesting and perhaps surprising places where clutches can be found.

How CVTs Work

In a regular transmission, the gears are literal gears -- interlocking, toothed wheels. Continuously variable transmissions, on the other hand, don't have interlocking gears. The most common type operates on a pulley system. Learn all about the smooth-operating, ultra-efficient CVT.

How Differentials Work

Without a differential, the driven wheels (front wheels on a front-wheel drive car or rear wheels on a rear-wheel drive car) would have to be locked together, forced to spin at the same speed. Find out how this essential component allows the wheels to rotate at different speeds.


Braking System

How Brakes Work

A car's brakes are probably the most critical system on the vehicle -- if they go out, you have a major problem. Thanks to leverage, hydraulics and friction, braking systems provide incredible stopping power. Find out what happens after you push the brake pedal.


How Disc Brakes Work

Disc brakes are the most common brakes found on a car's front wheels, and they're often on all four. This is the part of the brake system that does the actual work of stopping the car. Find out all about disc brakes -- even when to replace the pads.

How Anti-lock Brakes Work

Stopping a car in a hurry on a slippery road can be challenging at best and at worst, very, very scary. Anti-lock braking systems (ABS) help alleviate the danger. Learn how anti-lock brakes prevent skidding, check out what that sputtering is and find out how effective they really are.

How Power Brakes Work

Power brakes are fairly ingenious machines -- they let you stop a car with a simple twitch of your foot. The concept at the heart of the power braking system is force multiplication -- a whole lot of force multiplication. Get inside the black cannister that provides the power.

How Master Cylinders and Combination Valves Work

We all know that pushing down on the brake pedal slows a car to a stop. We depend on that every day when we drive. But how does this happen? The master cylinder provides the pressure that engages your car brakes. Learn how the master cylinder works with the combination valve to make sure you can brake safely.


Steering, Suspension and Tires

How Steering Works

When it comes to crucial automotive systems, steering is right up there with the engine and the brakes. Power steering systems make the job a whole lot easier, and the internal workings are pretty cool. What happens when you turn your car is not as simple as you might think. Find out all about car steering systems.


How Car Suspensions Work

All of the power generated by a car engine is useless if the driver can't control the car. The job of a car suspension is enormous: maximize the friction between the tires and the road surface, provide steering stability and ensure the comfort of the passengers. Learn how car suspensions work and where the design is headed in the future.

How Tires Work

In the market for new set of tires? All of the different tire specifications and confusing jargon the tire sales clerks or "experts" are shouting at you making your head feel like a tire spinning out of control? Find out all about car tires, including what those sidewall symbols mean!

How Self-inflating Tires Work

Self-inflating tires perform two crucial functions: They automatically maintain ideal tire pressure for safety and performance in standard conditions, and they allow the driver to alter psi on the fly to adjust to changing terrain. Learn how self-inflating systems like the Hummer's CTIS work.

How Sequential Gearboxes Work

Combine the ease of an automatic with the driver control of a manual, and what you've got is a sequential manual transmission. Instead of having to navigate an H pattern, a simple forward push advances the gear. It's the transmission used by race cars and an increasing number of high-performance street cars. Learn all about the sequential gearbox.

How Torque Converters Work

Cars with an automatic transmission have no clutch that disconnects the transmission from the engine. Instead, they use an amazing device called a torque converter. Find out all about the torque converter.


Electrical System

How Wires, Fuses and Connectors Work

Wires, fuses and connectors - they may sound like the most mundane parts on your car, but they are essential. Yeah, they help keep the tunes going for a long ride, and they make reading that map at night a lot easier. But, they're also necessary for things like the cooling fan in the engine and your anti-lock brakes. Learn why wires, fuses and connectors are so important!


How Ignition Systems Work

A car's ignition system is the key component that helps the engine produce maximum power and minimum pollution. Find out how much is riding on a well-timed spark.

How Car Computers Work

Cars seem to get more complicated with each passing year. Today's cars might have as many as 50 microprocessors on them. Essentially, you're driving around in a giant computer. Learn all about the various computer systems that control your car.

How Windshield Wipers Work

Without windshield wipers, a rain storm would make cars pretty much useless. What began as a hand-cranked system is now automatic, and only getting more so: There are now some windshield wipers that can actually sense rain. Learn the mechanics behind this essential automotive tool.


Exhaust System

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 catalytic converters reduce pollutants and help you pass the emissions test.


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 pretty neat technology to dim the roar of an engine. Learn about the principles that make it work.


Other Car Parts

How Odometers Work

Mechanical odometers have been counting the miles for centuries. Although they are a dying breed, they are incredibly cool inside. Learn how this simple device tracks distance and find out about digital odometers.


How Cooling Systems Work

A car engine produces so much heat that there is an entire system in your car designed to cool the engine down to its ideal temperature. In fact, the cooling system on a car driving down the freeway dissipates enough heat to heat two average-sized houses! Learn all about fluid-based cooling systems.


Frequently Asked Questions

How can I identify if a car part needs replacement?
Look for signs of wear such as unusual noises, decreased performance or visual deterioration, and consult your vehicle's manual or a professional mechanic for specific guidelines.
What are the risks of using aftermarket car parts?
Aftermarket parts may not always meet the OEM standards, potentially leading to compatibility issues, decreased performance or voiding the warranty.