Ever looked under your car’s hood and wondered what was happening? Uninitiated can find the engine of a car confusing with all its metal tubes, wires and tubes.

It’s possible that you just want to find out what’s happening. Perhaps you’re thinking about buying a new car and hear phrases like “2.5-liter inline four”, “turbocharged”, and “start/stop technology.” What does this all mean?

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This article will discuss the basics of an engine, then we’ll go in detail about how the parts fit together, how they can be damaged, and how to improve performance.

A gasoline engine’s purpose is to convert gasoline into movement so your car can move. The simplest way to make gasoline move is to use the gasoline in an engine. A car engine is an Internal combustion enginert.com — combustion occurs internally.

There are two things you should know:

  • There are many types of internal combustion engines. Gas turbine engines and diesel engines are two types of internal combustion engines. Each type has its advantages and disadvantages.
  • The external combustion engine is another option. An external combustion engine is best illustrated by the steam engine found in steamboats and old-fashioned trains. A steam engine’s fuel (coal or wood oil) is burned outside to produce steam. The steam then creates motion within the engine. External combustion is more efficient than internal combustion. An internal combustion engine is also smaller.

Internal combustion

Any reciprocating internal combustion engine works on the principle that a small amount of high-energy fuel (like gasoline), is placed in an enclosed area and ignited. This creates an amazing amount of energy in the form of expanding gases.

That energy can be used for many different purposes. If you can create a cycle that allows for explosions like these hundreds of times per second, and if that energy can be harnessed in a useful manner, you will have the core of a car’s engine.

Nearly every gasoline-powered car uses a four stroke combustion cycle that converts gasoline into motion. In honor of Nikolaus Otto who invent it in 1867, the four-stroke approach is also called the Ottocycle. The animation illustrates the four strokes. These are:

  • Take-off stroke
  • Compression stroke
  • Combustion stroke
  • Exhaust stroke

A connecting rod connects the piston to the crankshaft. The crankshaft rotates and has the effect of “resetting” the cannon. This is what happens during the engine’s cycle.

  • The piston is located at the top. Once the intake valve has opened, the piston lowers to allow the engine to take in gasoline and air. This is the intake stroke. This only requires that the gasoline be mixed in the air. Part 1 of the animation
  • The piston then moves up to compress the fuel/air mixture. Compression increases the power of the explosion. Part 2 of the animation
  • The spark plug ignites the gasoline when the piston reaches its maximum stroke. The gasoline charge in the cylinder explodes and drives the piston down. (Part 3 in the animation).
  • The exhaust valve opens once the piston reaches the bottom of its stroke. (Part 4 in the animation).
  • The engine is now ready to go for the next cycle. It will then take in another charge of gas and air.

The crankshaft converts the linear motion of the pistons into rotational motion in an engine. Because we intend to turn (rotate the car’s wheels) with it, the rotational motion is very useful.

Let’s now look at the various parts that make this possible, starting with the pistons.

Basic Engine Parts

The cylinder is the core of an engine. It contains the piston that moves up and down within the cylinder. Although single-cylinder engines are the most common for lawn mowers, cars usually have four, six, and eight cylinders. Multi-cylinder engines usually have three cylinder arrangements: inline V and flat. These cylinders are also known as horizontally opposed, boxer, or boxer.

Inline four, which we have already mentioned, is an engine that has four cylinders in a straight line. Different configurations offer different benefits and disadvantages in terms manufacturing cost, smoothness, and shape characteristics. These features make them more appropriate for certain vehicles.

Let’s take a closer look at key parts of the engine.

Spark plug

The spark plug provides the spark that ignites air/fuel mixture so combustion can occur. For things to work correctly, the spark must occur at the right time.


When the intake and exhaust valves are opened, they allow air and fuel to enter and exit at the appropriate times. Both valves close during compression and combustion to seal the combustion chamber.


A piston is a cylindrical metal piece that moves inside a cylinder.

Piston Rings

Piston rings act as a seal between the outer edge and inner edges of the piston. These rings serve two purposes.

They prevent fuel/air mixture, and exhaust from the combustion chambers from leaching into the sump during compression or combustion.
They prevent oil from leaking into the combustion zone, where it could be burned or lost.
Cars that “burn oil” and require a quart of oil every 1,000 miles are likely burning old oil because their rings have failed to seal properly. Modern vehicles have piston rings made from more advanced materials. This is one reason why engines last longer between oil change.

Connecting rod

The connecting rod links the crankshaft and the piston. It can turn at both ends, so its angle can change with the movement of the crankshaft and piston.

The crankshaft converts the piston’s up and down motion into circular motion, just like a crank in a jackinthe-box.


The crankshaft is surrounded by the sump. It is surrounded by oil. This oil collects at the bottom of the sump (the pan).

Next, we will learn about the potential problems with engines.

Engine problems

You go out one morning, and your engine won’t turn over. What could possibly be wrong? You now know the basics of how an engine works and can identify what can stop it from running.

There are three main things that can go wrong: bad fuel, lack of compression, or a lack of spark. There are many other things that can cause problems beyond these three. Let’s take a look at the engine that we just discussed. Here is a quick overview of how these problems can affect your engine.

Bad fuel mix may occur in many ways

  • You are out gas so the engine is getting fuel but not air.
  • It is possible that the air intake has become blocked.
  • It is possible that the fuel system is supplying too much fuel or not enough fuel to the mixture, causing combustion problems.
  • Fuel may not burn because of an impurity (such as water in your tank).

Inadequate compression: The combustion process won’t work as it should if the fuel and air charge are not properly compressed. These are some possible reasons why you might experience lack of compression:

  • Your piston rings have worn, allowing the fuel/air mixture to escape past the piston during compression.
  • There is a possibility of leakage during compression if the intake and exhaust valves do not seal properly.
  • The cylinder has a hole.

The most common hole in a cylinder is where the top of it attaches to the body. This holds the spark plug and valves. Also known as the cylinder head . To ensure a tight seal, the cylinder and cylinder head are bolted together using a thin gasket. Small holes can form between the cylinder’s head and the gasket, which can lead to leaks.

No spark: There could be many reasons why the spark is weak or non-existent.

  • The spark can be weakened if the wire or sparkplug is damaged.
  • There will not be spark if the wire is missing or cut, or the system that sends sparks down the wire isn’t working correctly.
  • The spark may not ignite if it occurs too soon or too late in the ignition cycle (i.e. The fuel won’t ignite if the ignition timing has been off.

There are many other things that could go wrong. Take, for example:

  • You cannot start the engine if the battery has died.
  • The bearings which allow the crankshaft’s freedom of movement are worn, and the crankshaft can’t turn, so the engine won’t run.
  • The engine will not run if the valves don’t open or close correctly.
  • The engine will stop moving if there isn’t enough oil.
  • All of these factors work fine in a properly functioning engine. Although perfection is not necessary to make an engine work, you will notice when things aren’t quite right.

An engine is composed of many systems. In the next sections, we’ll be looking at different subsystems that are used in engines.

Engine Valve Train and Ignition Systems

Many engine subsystems can use different technologies. Better technologies can increase the engine’s performance. Let’s take a look at the various subsystems found in modern engines starting with the valve train.

The valve train is composed of valves and a mechanism to open and close them. The opening and closing mechanism is known as a crank . The camshaft is equipped with lobes that allow the valves to move up and down as shown in Figure 5.

Modern engines use overhead cameras. As shown in Figure 5, this means that the camshaft is above the valves. The shaft’s cams activate the valves either directly or via a short linkage. An older engine had a camshaft in the sump, near the crankshaft.

The timing chain or timing strap links the crankshaft and camshaft, ensuring that the pistons and valves are in synch. The camshaft rotates at half the speed of the crankshaft. High-performance engines often have four valves per engine (two for intake and two for exhaust). This arrangement means that there are two camshafts per bank. The term “dual overhead cams” is used to describe the two camshafts.

Figure 6 shows how the ignition system produces high-voltage electric charge that is transmitted to spark plugs using ignition wires. You can find a distributor under most cars. One wire runs through the distributor and depending on how many cylinders it has, there are four, six, or eight wires coming out of the distributor. These spark plug wires transmit the charge. Each spark plug is only given one spark by the distributor. This allows for maximum smoothness.

In the next section, we’ll examine how your car’s engine cools, starts and circulates air.

Engine cooling, air-intake and starting systems

Most cars’ cooling systems consist of the radiator or water pump. The radiator cools the engine by circulating water through the tubes. The engine of some cars, such as the pre-1999 Volkswagen Beetles, as well as many motorcycles or lawn mowers is air-cooled. To dissipate heat, you can see the fins on the outside of each piston. Air cooling makes the engine lighter and more efficient, which in turn reduces engine life and improves overall performance.

Now you understand how and why your engine keeps cool. Why is air circulation so important, you ask? The majority of cars are normally aspirated. This means that air flows through an intake filter and into the cylinders. Modern, high-performance engines that are fuel-efficient and efficient are either turbocharged (or supercharged). This means that the air entering the engine is first pressured (so more air/fuel mixture can squeeze into each cylinder). This increases performance. boost is the amount of pressure. A turbocharger attaches a small turbine to the exhaust pipe. It spins a compressing turbine in incoming air stream. To spin the compressor, a supercharger is attached to the engine.

The turbocharger uses hot exhaust to spin and compress the air. This increases power from smaller engines. A fuel-sipping four-cylinder engine can produce the same horsepower as a six-cylinder engine, while achieving 10 to 30% better fuel economy.

It is possible to increase your engine’s performance, but how do you start it? The starter system is composed of an electric starter motor, and a starter solenoid. The starter motor spins your engine for a few turns so that the combustion process can begin. A powerful motor is required to spin a cold engine. The starter motor must be able to:

  • All internal friction created by the piston rings
  • Any cylinders that happen to be in the compression stroke will have a compression pressure of 0.25 bar.
  • The energy required to open and close the valves with camshaft
  • All other items directly connected to the engine such as the oil pump, water pump, alternator and alternator.

A car’s 12-volt electrical system requires a lot of energy. Therefore, the starter motor must draw hundreds of amps of electricity. This is basically a large electronic switch capable of handling that much current. The solenoid activates when you turn the ignition key to power the motor.

Next we will look at the subsystems of an engine that keep what goes in (oil, fuel) and what comes back (exhaust or emissions).

Engine Lubrication, Fuel, Exhaust, and Electrical System

Your first concern when it comes to car maintenance is likely the gas level. How does the gas you put into your car power the cylinders of the engine? The engine’s gasoline system pumps fuel from the tank and mixes it in with air to create the right mixture of air and fuel that can flow into the engines. Modern vehicles use two types of fuel delivery: direct fuel injection or port fuel injection.

A fuel-injected engine injects the correct amount of fuel into each cylinder. This is done either directly or above the intake valve (portfuel injection). Carburetor technology was used in older vehicles to mix gas and air as it flowed into them.

Another important role is oil. The Lubrication system ensures that every part of the engine moves smoothly by providing oil to all moving parts. The pistons are essential to ensure that they slide in their cylinders and all bearings allow for things like the crankshaft or camshafts, which can rotate freely, need oil. Oil is taken out of the oil pan using an oil pump. The oil is then run through an oil filter to remove any grit and then sprayed under high pressure onto the bearings and cylinder walls. The oil is then sucked into the sump where it is then collected and repeated.

Let’s now look at what happens to after you have learned about the stuff you put into your vehicle. The exhaust system comprises the exhaust pipe as well as the muffle. You would hear thousands of tiny explosions coming from your tailpipe without a muffler. The sound is muffled by a muffler.

Modern cars have a emission control device that consists of a catalyst, several sensors and actuators, as well as a computer to adjust and monitor everything. The catalytic converter burns any fuel left over and other chemicals from the exhaust. The exhaust stream has an oxygen sensor that ensures there is enough oxygen for the catalyst to function and can be adjusted if necessary.

What other fuels your car, besides gas? An alternator and a battery make up the electrical system. The alternator is connected by a belt to the engine and generates electricity to charge the battery. The battery provides 12-volt power to all electrical components in the vehicle (radio, ignition, windshield wipers and power windows as well as seats and computers). Through the vehicle’s wiring.

Let’s now look at how you can improve engine performance.

More engine power

All of this information will allow you to see the many ways an engine can be improved. To make their engines more powerful or more efficient, car manufacturers constantly experiment with the following variables.

Increase displacement. More displacement equals more power, as you can burn more fuel each revolution. You can increase the displacement by increasing the number of cylinders or adding more. Twelve cylinders seems like the limit.

Increase compression ratio: Higher compression rates produce more power up to a certain point. However, the greater the compression ratio, the more the fuel mixture will spontaneously ignite (before the spark plug ignites). High-octane gasolines can prevent early combustion. High-performance cars require high-octane gasoline to make more power.

Put more fuel into each cylinder. You can get more power out of a cylinder if you can pack more air and fuel into it. Superchargers or turbochargers pressurize the airflow to force more air into acylinder.

Cool the inflowing air. Air is heated by compression. You want to make sure that the air in your cylinder is cool. Because the more hot the air, the more it expands when combustion occurs. Many supercharged and turbocharged cars come with an intercooler. An intercooler is a radiator that cools compressed air before it enters a cylinder.

Allow air to flow more easily: Air resistance is when a piston moves down during the intake stroke. This can reduce the engine’s power. Two intake valves can be installed in each cylinder to reduce air resistance. To eliminate air resistance, some cars have polished intake manifolds. Air flow can be improved by using larger air filters.

Allow exhaust to exit more easily: Air resistance can make it difficult for exhaust exit a cylinder. This reduces engine power. A second exhaust valve can be added to each cylinder to reduce air resistance. Four valves per cylinder are possible in a car that has two intake and two exit valves. This improves its performance. A car advertisement may tell you that the car has four cylinders with 16 valves. However, the ad actually says that the engine has four valves per piston.

Back-pressure can also occur if the exhaust pipe is too short or the muffler has high air resistance. High-performance exhaust systems have large headers, big tail pipes, and free-flowing muffles to reduce back-pressure. Dual exhaust refers to a vehicle that has two exhaust pipes. This is done to increase the exhaust flow.

Make everything lighter. Lightweight parts make the engine run better. Every time a piston moves in a different direction, it expends energy to stop it from moving in the other direction and begin it in the next. The piston that is lighter uses less energy. This improves fuel efficiency and performance.

Inject fuel: Fuel inject allows for precise fuel metering to each cylinder. This increases performance and fuel economy.

We’ll be answering common questions about engines in the sections that follow.

Questions and answers about engines

Below are some questions and answers about engines.

  • What’s the difference between a gasoline engine or a diesel one? A diesel engine has no spark plug. Diesel fuel is instead injected into the engine. The heat and pressure from the compression stroke causes the fuel to ignite. Diesel fuel is more efficient than gasoline because it has a higher energy density. This allows for better mileage. See How Diesel Engines Work for more information.
  • What’s the difference between a three-stroke and two-stroke engine? The majority of boat motors and chainsaws use two-stroke engines. Two-stroke engines have no moving valves and the spark plug ignites when the piston reaches the end of its cycle. The lower portion of the cylinder wall has a hole that allows gas and air to enter. The piston is compressed as it moves up, and the spark plug ignites combustion. Exhaust exits through another hole in a cylinder. Two-stroke engines require that you mix oil with the gas because of the holes in the wall of the cylinder. Rings are not possible to seal the combustion chamber. A two-stroke engine is generally larger than it needs to produce a lot of power due to the fact that there are twice as many combustion cycle per rotation. A two-stroke engine is more polluting because it uses more gasoline and burns more oil. For more information, see How Two-stroke engines Work.
  • You’ve mentioned steam engines in your article. A steam engine can burn any fuel. A steam engine can burn coal, paper, or wood as the fuel. An internal combustion engine requires a high-quality, liquid or gaseous fuel. For more information, see How Steam Engines Works.
  • Why do you need eight cylinders? Why not use one big cylinder with the same displacement as the eight cylinders? Smoothness is the main reason. The V-8 engine has eight evenly spaced explosions, which makes it much more smooth. Another reason is to start torque. A V-8 engine only drives two cylinders (1-liter) through compression strokes. But, if you want to drive a larger cylinder, you’d have to compress 4 Liters.

Anita Wagner

She loves history and has a PhD in History and Antopology. Loves to dig up a past.

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