What Makes Up a Modern Diesel Engine?

Not too long ago, diesel engines were viewed as smelly, underpowered, and noisy mechanical contraptions that proved to be of little value, other than for taxis, vans, and trucks.

However, the modern diesel engine—with its injection system controls—is a completely different story. Not only are these engines refined to the point where they’re more cost-effective than their gasoline counterparts, but they also provide a host of other benefits.

In this blog, we’ll go into the nitty-gritty of what makes up a modern diesel engine.

Diesel Engine Construction

The main components of a petrol and diesel engine look similar, and even perform the same tasks. However, because diesel engines have to deal with greater pressure compared to a petrol engine, they’re constructed using stronger materials. The engine block walls are thicker and have additional bracing webs to absorb stress and provide extra strength. Apart from withstanding shocks, diesel engines are also effective in reducing noise.

Connecting rods, pistons, bearing caps, and crankshafts also have to be constructed with stronger materials. Additionally, cylinder heads are also of a different design. For more information, you can consult the 2nd Edition of Modern Diesel Technology: Diesel Engines online.

Direct Injection

Direct injectors in a diesel engine spray fuel directly above the piston. There isn’t any swirl or pre-chamber to speak of, and the fuel doesn’t have to travel via the intake manifold before it’s allowed to enter the cylinder. Direct injection makes the internal combustion process much simpler, more efficient, and quicker compared to a multi-port gasoline engine.

Direct Injection engines also have an impressive air to fuel ratios which usually hover from 25:1 to 40:1, whereas the figures are 12:1 to 15:1 for gasoline engines. This is why diesel engines are more fuel efficient. So efficient, in fact, that modern day engines exert a pressure of around 30,000 psi or more, which leads to fine atomization of the fuel particles and results in lower energy wastage.

Air Intake

Let’s look at a 4-stroke, intercooled and turbocharged diesel engine to explain the flow of fuel and air. Fresh air enters the intake side and is immediately compressed where the boost is created. This makes the air warmer and much denser. The air is then routed via an intercooler before it enters the cylinder head with minimal boost loss.


With fuel economy taking center stage, manufacturers are turning to diesel engines as a viable choice. ATL Diesel offers quality diesel engine parts from the finest manufacturers. They have the largest inventory in North America of diesel engine parts and offer free shipping nationwide. Contact us today for more information.