How Does an Internal Combustion Engine Work? (Gas and Diesel)

(Updated on October 15, 2021)

An internal combustion engine is found in most vehicles that are on the road. It is the main power source which gives a vehicle its mobility to accelerate and move around. These engines exist for both gasoline fuel and diesel fuel. The newer hybrid vehicles contain a combination of an internal combustion engine and electric motor. However, most people in the developed world are highly dependent on internal combustion engines. If the world did not have them, the transportation industry would cease to exist.

How an Internal Combustion Engine Works

The internal combustion process revolves around two main elements; air and fuel. There is a chamber within the engine where the proper amount of air and fuel flow into. The two elements mix together and then get ignited by an electric spark. This results in heat energy being released from the air and fuel mixture. The heat energy is the result of expanding gases that came from the mixture after it was put through combustion. These gases make their way to the pistons which then causes the crankshaft to rotate. From there, the powertrain of the vehicle is comprised of numerous gears that all move in-sync with each other. As the gears move, the wheels below the vehicle will move too. This is how the vehicle can gain motion and move after the internal combustion takes place in the engine.

Gasoline vs Diesel

Not all internal combustion engines rely on a spark ignition system, though. There is another type of internal combustion engine which relies on a compression ignition system instead. This would be the diesel engine. Rather than the spark plugs sending an electric current to the air and fuel mixture to ignite them together, the air inside a diesel engine will get compressed first until it is very hot. Once the diesel fuel is exposed to this hot compressed air, an ignition will naturally take place without the need for an outside spark. You will normally find diesel engines being used in bigger vehicles because of their fuel efficiency way about them.

Regardless of whether you have a diesel engine or gasoline engine, each one uses a four-stroke cycle for combustion. You can think of four strokes as the four steps that it takes for the combustion process to finish one cycle. These four strokes are called the intake stroke, compression stroke, combustion stroke, and exhaust stroke. The only real difference in the four-stroke cycle of each engine type is how the fuel is ignited. The gasoline engine uses the spark plugs to ignite the fuel while the diesel engine uses compressed air to ignite the fuel. Everything else about the four strokes is pretty much the same. You have an intake of outside air which gets pushed down into the cylinders by the rotating pistons. When the air and fuel are mixed together, there is an ignition which forms the combustion stroke. The gases of the heat energy will expand to the pistons, which then moves the gears and give motion to the wheels.

Modern Developments

The modern-day internal combustion engine is designed to be more environmentally friendly. Car manufacturers are always looking for ways to make their engines more fuel efficiency so that drivers will experience a better fuel economy. However, the interest in renewable energy and fully electric vehicles may put a damper on the future of internal combustion engines. There are already 100% electric-powered vehicles out right now which use an electric motor and battery to sustain its motion. These are not the most powerful vehicles for traveling at high speeds, but they can allow people to move around their town or city area without too much hassle. In the next 30 years, the advancement of solar and fuel cell energy might cause internal combustion engines to become obsolete.

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