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Understanding How Diesel Car Engines Actually Work in Practice

Did you know that diesel and gasoline vehicles are similar? They both have internal combustion engines. There is one difference. Diesel engines use a compression-ignited injection mechanism. Gasoline cars use the spark-ignition system.

The primary benefit of diesel engines over gasoline engines is their reduced operating costs. This is due in part to the higher performance of the high compression ratio diesel engine and in part to the reduced cost of diesel fuel.

Service cycles are often extended as well. However, many diesel engines need more regular oil changes than their gasoline equivalents.

Here’s a brief guide that helps you understand how diesel car engines actually work.

How Diesel Car Engines Work

Diesel engines have long been regarded as loud, stinky, and underpowered heavy duty diesel engines. People thought trucks, taxis, and buses were the only vehicles using diesel engines. That is not the case anymore.

A diesel engine, like a gasoline engine, is an internal combustion engine. Internal combustion engines are essentially those in which the fuel is burnt within the main part of the engine. That is where power generates.

A diesel engine, like a gasoline engine, usually works by repeating a series of four phases or strokes. During these strokes, the piston goes up and down twice during the cycle. In other words, that means that the crankshaft turns twice during the cycle.

The Single Intake Valve

The inlet valve opens and the air is drawn in when the piston starts to travel down the chamber. At the bottom of the stroke, the inlet valve shuts. 

Compression of the Air

The inlet valve shuts, the piston rises to the top of the cylinder by the force of the other pistons and the momentum of the flywheel. It compacts the air to around a twentieth of its original amount.

A specifically metered amount of diesel fuel is pumped into the combustion chamber. This happens when the piston approaches its uppermost height. The heat from compression instantly ignites the fuel/air mixture, allowing it to combust and spread. This causes the piston to descend, spinning the crankshaft.

Unlike a gasoline engine, no spark plug is needed to accomplish this.

Power Stroke

During the power stroke, the expansion of the combustion gases pushes the piston. When the air-fuel mixture ignites and fires, it forces the piston down. That causes the crankshaft to turn and to drive the wheels. 

Exhaust Gases

The exhaust valve expands as the piston pushes up the cylinder on the exhaust stroke. That allows the burnt and expanded exhaust fumes to flow down and out the exhaust pipe. The cylinder is now primed for a fresh charge of air at the end of the exhaust stroke.

Up and Down and Fire!

Now you know how diesel car engines work! 

The diesel engine’s most notable characteristic is its performance. The diesel engine is not constrained by the preignition issues that affect high-compression spark-ignition engines. That is because it compresses air rather than using an air-fuel mixture. 

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