How Diesel Engines Work

Gasoline v. Diesel

Wondering what makes diesel engines different from gasoline-powered ones? A&M Auto Repair in Bellevue, Washington has the answers. As diesel repair specialists, we know everything about these engines and how to fix them!

How They Are Different

A diesel engine uses fuel injectors to spray fuel into the combustion chamber, where the air pressure is so high that the fuel ignites spontaneously.

A gasoline engine mixes air and fuel in the cylinder then uses a spark to ignite it under pressure from a piston. The expansion of the combustion pushes the piston.

The Process

Step 1

When you start a diesel engine, you may not release everything that’s happening to get the car to turn over. Diesel engines work better when they are preheated because the fuel is less volatile. The fuel passes through filters before it is injected through the nozzles to prevent clogging. Turning the key starts the ignition process where fuel injects into the cylinders under very high pressure. The intense pressure causes rapid heating. From here, a “start” light illuminates, and the driver can press the accelerator.

Step 2

Fuel is pressurized in a delivery tube, called the rail, that sustains a high pressure above 23,000 pounds per square inch (psi). Gasoline fuel injection may be pressurized between 10 and 50 psi! The engine’s control unit (ECU) determines the exact pressure, spray timing, and how long the spray should last to deliver power.

Step 3

While one process moves the fuel to the combustion chamber, another moves the air where it needs to go. In conventional diesel engines air passes through a filter. This is where turbochargers are added to increase the volume of air intake. Turbochargers can increase power by 50% and lower fuel consumption by 20-25%.

Step 4

The fuel and air mixture in the main combustion chamber ignites to power the vehicle.

Diesel Repair

It’s clear that diesel engines work differently than gasoline ones. That’s why you need an expert to perform diesel repairs. Visit A&M Auto Repair Bellevue for your next service.