You saw last week what it takes for air to go through an engine, get mixed with fuel, get turned into power, and exit a car through the exhaust. This week, we’re going to look a bit more into some more of the things you can find under your hood that help your engine run its best.
Before we get into more components, though, we have to talk about the actual engine of a car just a little more. Generally speaking, the more cylinders a car’s engine has, the more power it can produce because of its greater capacity. A car can also produce more power by using larger cylinders. The displacement of an engine is the amount of total volume of all its cylinders combined.
The configuring of an engine describes its layout. More specifically, it has to do with cylinder and piston orientation. Engines come in all kinds of configurations. The three basic types of engines are inline engines, “V” engines, and flat engines. All three of these have various amounts of cylinders that make an engine exactly what it is. The inline 4 cylinder is the most common engine used in cars today.
Common Engine Layouts:
Inline 4:
Photo: Courtesy of How Stuff Works
This is the most common engine type used in cars today. Prized for its combination of tuning potential, easy maintenance, and simple design, it’s even started to appear in large SUVs and some trucks. It gets its name from the four cylinders that form a straight line down the engine block.
Inline 6:
Photo: Courtesy of Automotive News
This engine is largely defunct because it adds two more cylinders to the regular inline four cylinder mentioned above. This makes the engine longer and takes up more space which is largely impractical anymore. Regardless, some of the best engines ever made have been inline six cylinder engines.
Boxer Engine:
Photo: Courtesy of GT Speed
Boxer engines get their name from the way the pistons move. Cylinders in a boxer engine are horizontally opposed, and, instead of moving straight up and down in a straight line, the pistons move away from each other, toward the sides of the car.
The name “Boxer” comes from the movement of the pistons “punching” away from the center of the engine.
Flat 4:
The most common application for the flat four is in Subaru vehicles. Two pistons move away from the center of the crankshaft toward one side of the car and the other two move in the opposite direction. The advantage of this engine is a lower center of gravity as the engine isn’t as tall as a regular inline four.
Flat 6:
The flat six is the same as the flat four with the addition of one more cylinder on each side of the crankshaft. Porsche is famous for using this engine in their vehicles.
V6:
Photo: Courtesy of Car Throttle
The V6 engine has become less popular in recent years than it used to be, but you can still find them. It gets its name from the “V” shape formed by the banked cylinders. Engines can be banked anywhere from 45-90 degrees, with three cylinders angled upward on each side of the crankshaft.
V8:
The V8 is more popular than the V6 anymore and is the engine of choice for many American high-performance cars such as the Mustang, Corvette, and Challenger. Even some Ferraris, Mercedes Benz, and other performance cars us a V8 engine.
The difference, of course, between the V8 and V6 is the addition of two banked cylinders added to the engine block, making the engine generally capable of producing more power.
V10 and V12:
Photo: Courtesy of Hot Rod Network
Both of these engines are quickly becoming extinct.
The V10 is still used in the Audi R8, but it has been used in the Lexus LFA, BMW M5, and Dodge Viper. The V10 was never as popular as the V12, but many great engines have been V10s, and we’re sad that it’s disappearing.
V12 engines have been used famously in Ferraris and Lamborghinis. Some Ferraris, Lamborghinis, and Aston Martins still use the V12 as it is a quintessential engine for a supercar, but even these are being phased out for V8 engines or other variations coupled with turbochargers to make power.
Inline 3:
Photo: Courtesy of Automotive News
Inline three cylinder engines are understandably used mostly in subcompact cars. The Smart ForTwo, Mitsubishi Mirage, and even the Ford Focus EcoBoost all offer a three cylinder engine. Though the Focus is offered with a three cylinder engine, it is optional and isn’t on all trim levels.
While not incredibly popular in the United States, Japanese and European cars utilize the three cylinder engine much more.
Inline 5:
Another engine that isn’t as popular and is losing the battle to the four cylinder is the inline five. Audi, Volkswagen, and Volvo have traditionally utilized it the most, but it still wasn’t in the majority of their cars at any given time.
The five cylinder engine is one that not many people know or think about, but its calling card is the way it sounds. Five cylinder engines have been known to be produce some of the best sounding, and most underrated cars, ever made.
Rotary Engine:
We could dedicate a whole book about the rotary engine, but you’ll have to settle for a paragraph or two. The reason for this is because the engine is completely different than any other on this list.
The rotary engine doesn’t have pistons, but rather a triangular-shaped rotor that rotates within an oval shaped chamber. As the rotor spins, it draws in air, compresses it, and ignites the air fuel mixture as it seals off chambers. It’s hard to explain without seeing it so take a look at this:
Rotary Engine Video
Rotary engines are world-renown for being inefficient, unreliable, and consuming massive amounts of oil. On the other hand, they are also known for being incredibly smooth, creating a unique and heavenly exhaust note, and revving higher than any other engine.
They are beloved by many in the enthusiast community, but are simply too impractical for most applications. This is why there aren’t any current production models that utilize the rotary engine.
The most recent car to use a rotary engine was the Mazda RX-8, which was discontinued in 2012. With few exceptions, the rotary engine goes hand in hand with Mazda. They were the only ones to put the time and money into developing it and using it extensively in their vehicles, and unreliable as it was, they made it work.
Other notable rotary-powered cars were the Mazda RX-7, Mazda Rotary Pickup, and Mazda 787B. The 787B was a LeMans race car which won the 24 hours of LeMans. It was the only Japanese car to ever do so.
Additional Parts:
There are many more parts that make up an engine than just the pistons, camshaft, and exhaust. Though not directly bringing in air, compressing it, mixing it with fuel, and producing power, these other parts play an important role in making your vehicle move.
Battery:
You and I know that batteries do things like help a car start. We also know that it can be a pain when the battery stops doing that, and we have to have a jump-start. It also helps power the other electrical systems in the car when the alternator’s abilities are exceeded.
Alternator:
The alternator is responsible for charging the battery and keeping all the electrical systems working when the car is actually running.
Dead batteries aren’t the only thing that can prevent your car from starting up in the morning. The alternator, if broken, won’t recharge the battery, and you could have the same problem as a dead battery even though the battery works perfectly fine.
Starter:
The starter is what give the engine its initial movement and causes it to “turn over.” Powered by the battery, the starter functions as an electric hand crank we all used to see in old movies to start a car.
ECU:
The ECU is the Engine Control Unit, and it’s the computer of the car. In modern cars, the ECU controls everything from the air and fuel ratio to transmission timing to the car’s rev limit.
ECUs are programmable. Many modern cars can be modified or changed without adding parts simply by buying a new ECU or performing a “re-flash.” You can even get potentially better fuel economy or better performance by reprogramming the ECU.
Radiator:
The radiator is the large metal mesh piece you can see when you look through the grille of a car. Coolant is circulated through a radiator after it passes through the engine block in order to re-cool it. Afterwords, it’s again circulated through the engine to cool the engine.
Electric cars don’t require radiators as they don’t have an engine block, along with all the moving parts of a regular internal combustion engine.
Serpentine Belt:
The serpentine belt is turned when the engine is started and is used to power the air conditioning, alternator, and water pump, among a few other auxiliary systems under the hood. If you open the hood of your car, you can see the serpentine belt doing its job if your engine in on and there isn’t a cover over all the components.
Fuel Pump:
The fuel pump is pretty self-explanatory. It pumps fuel from the gas tank of your car, through a series of fuel lines, and keeps it moving to the injectors or carburetor. If your fuel pump fails, your car want to start as fuel simply can’t get to the injectors.
Sensors:
The newest vehicles have so many sensors under the hood that you can’t even count them. Here are some of the most common sensors:
Oxygen Sensor:
The oxygen sensor ensures the catalytic converter can function optimally by measuring the amount of oxygen in a vehicle’s exhaust. Adjustments in the air and fuel mixture are made by the ECU accordingly.
Throttle Position Sensor:
As the name would suggest, this sensor monitors a vehicle’s throttle position.
MAP (Manifold Absolute Pressure) Sensor:
The MAP sensor measures air density entering the cylinder and adjusts the amount of fuel for the best possible combustion.
Coolant Temperature Sensor:
The coolant temperature sensor can be seen by the light on your dashboard that looks like a thermometer floating in the ocean. It measures how hot or cool your engine is running.
Fuel Pressure Sensor:
Again, this one is fairly self-explanatory. The fuel pressure sensor measures the fuel pressure produced through the fuel system.
Modern cars have many more sensors that help a vehicle run the best it can, but most are fairly easy to understand if you look at what it’s called. All of them work together to help your engine run at its peak performance.
Turbocharger:
Photo: Courtesy of Consumer Guide
Turbos are becoming increasingly popular today in order to increase power output while also increasing fuel efficiency. It does this by using exhaust gases to spin a turbine. That turbine is also linked to an intake turbine which draws in air and compresses it. This, in turn, forces additional air into each cylinder, thus increasing horsepower.
Supercharger:
Photo: Courtesy of Car Throttle
Superchargers are similar to turbochargers in that they force a greater amount of compressed air into the cylinders of the engine, but they do it a different way. Superchargers are belt or chain-driven rather than powered by the exhaust gas produced by the engine. This means the superchargers uses a portion of the engine’s power to make them work.
Of course, that still isn’t all the components that live in the engine bay of the car to make it work, but it’s definitely a start. And the good news about all of this is that you can figure out pretty easily what each of these looks like by grabbing your owner’s manual and popping the hood of your car.
Even if you choose not to do that, hopefully you have a little better understanding of how your car’s engine works and the systems that help it run.
