HOW COMBUSTION ENGINES WORK

There are a lot of people out there who absolutely LOOOVE cars. They are all about all things cars. You know who we are talking about, those people who can hear an engine 3 blocks away and tell you how many liters, what year, and how many bolts hold it in. Then there is the rest of the population. They hear things like V-6, 3 liters, and dual overhead cams, and think they are hearing a foreign language. The purpose of this article is to help the non-gearheads understand a little bit more about how a gas engine works. Our thinking is, if you can understand how your engine works you might be able to better understand how to care for your engine, how to increase fuel efficiency, how to boost power, and how to increase performance all around (we are Boost Performance Products after all!)

Basically, your car’s engine is an internal combustion engine. That simply means that combustion (think explosion, burning, fire, etc.) happens inside your engine. The energy produced is turned into motion to propel you from home to work to the store or wherever you’re driving.

There are different kinds of internal combustion engines (a diesel engine is a great example). There are also external combustion engines. This article will focus on gas internal combustion engines (like the ones found in nearly every car).

Here is the basic principle. By putting a small amount of combustible fuel in tight quarters and exploding it, a lot of energy is produced (due to expansion of the gas). if you can harness those explosions and repeat them hundreds of times per minute,  you have enough power to propel your car. Almost all cars use a four-stroke cycle. The four strokes are:

• Intake stroke

• Compression stroke

• Combustion stroke

• Exhaust stroke

Here is how it works:

1. The piston starts at the top, the intake valve opens, and the piston moves down to let the engine take in a cylinder-full of air and gasoline. This is the intake stroke. Only the tiniest drop of gasoline needs to be mixed into the air for this to work.

2. Then the piston moves back up to compress this fuel/air mixture. Compression makes the explosion more powerful.

3. When the piston reaches the top of its stroke, the spark plug emits a spark to ignite the gasoline. The gasoline charge in the cylinder explodes, driving the piston down.

4. Once the piston hits the bottom of its stroke, the exhaust valve opens and the exhaust leaves the cylinder to go out the tailpipe.

This, with the help of the crankshaft, is turned into rotational motion. That is convenient because your car’s wheels need to use that type of motion power to go.

Here are some more details about some critical parts of your engine:

Spark plug

The spark plug supplies the spark that ignites the air/fuel mixture so that combustion can occur. The spark must happen at just the right moment for things to work properly.

Valves

The intake and exhaust valves open at the proper time to let in air and fuel and to let out exhaust. Note that both valves are closed during compression and combustion so that the combustion chamber is sealed.

Piston

A piston is a cylindrical piece of metal that moves up and down inside the cylinder.

Piston rings

Piston rings provide a sliding seal between the outer edge of the piston and the inner edge of the cylinder. The rings serve two purposes:

• They prevent the fuel/air mixture and exhaust in the combustion chamber from leaking into the sump during compression and combustion.

• They keep oil in the sump from leaking into the combustion area, where it would be burned and lost.

Most cars that "burn oil" and have to have a quart added every 1,000 miles are burning it because the engine is old and the rings no longer seal things properly.

Connecting rod

The connecting rod connects the piston to the crankshaft. It can rotate at both ends so that its angle can change as the piston moves and the crankshaft rotates.

Crankshaft

The crankshaft turns the piston's up and down motion into circular motion just like a crank on a jack-in-the-box does.

Sump

The sump surrounds the crankshaft. It contains some amount of oil, which collects in the bottom of the sump (the oil pan).

There can be several reasons you have engine problems, here are just a few:

• Bad fuel mix

• Lack of compression

• No Spark

In future articles we’ll go over lack of compression and spark issues. To close this article, let’s discuss what can be the problem if bad fuel mix is the culprit:

• You are out of gas, so the engine is getting air but no fuel.

• The air intake might be clogged, so there is fuel but not enough air.

• The fuel system might be supplying too much or too little fuel to the mix, meaning that combustion does not occur properly.

• There might be an impurity in the fuel (like water in your gas tank) that makes the fuel not burn.

One great way to solve these issues is to use a fuel additive. A quality fuel additive works by increasing the combustion quality of your fuel. This can do several things. First, the fuel additive can create a situation in which impure fuel can still ignite. Second, it will increase the power (remember that the explosion in a small space creates the engine power, more power from the explosion means more power to the car.). Third, the fuel additive’s ability to increase power can actually help clear out the fuel line.

Another thing you should do is be sure to use the proper fuel for your vehicle and get your car inspected regularly. Unfortunately there isn’t much you can do if you are out of gas except refill (though a fuel additive or supplement can boost engine efficiency as well which will increase fuel economy or MPG).