How Does a Diesel Fuel System Work

Diesel Performance Parts

While I was at my local Pet Store getting more dog food for Hooch – my Akita, I noticed a big diesel truck in the parking lot with a beautiful German shepherd in the bed waiting for its owner to return.

I’m a gear head and what caught my eye was I noticed this particular diesel truck used a fass fuel system, an aftermarket part. It got me thinking that a lot of my readers (mostly pet owners) might not know a lot about how cars and trucks work, and even though this is a break from my usual type of writing I hope you can read and learn quite a bit about how diesel engines work.

When you start a gas engine, an electrical spark causes a mixture of fuel and compressed air to combust, producing the energy required to move the car. A diesel fuel system doesn’t require an electrical spark.

It has mechanisms that inject pressurized (and atomized) fuel into the engine cylinders. The combination of hot compressed air and fuel eventually combusts. The diesel fuel system requires a number of components to operate efficiently, including:

1). You need diesel fuel. When crude oil is refined to make gasoline and other volatile fuels, the process produces heavier residues from which diesel fuel is derived.

diesel truck

2). Once you have the fuel, you need somewhere to keep it. This is where the fuel tank enters the picture. Tanks come in various forms. The size and shape will vary depending on the vehicle. Tanks require several elements to do their work. First of all, they need three openings for filling, draining, and discharge.

Secondly, the tank needs a cover to protect the fuel from contaminants. Thirdly, the tank should be large enough to store fuel in volumes that will keep the vehicle in operation for an extended period.

3). Once you have your fuel in a tank, you need a way to filter it. This is where fuel filters come into play. Because diesel fuel requires repeated filtering, your vehicle’s fuel system needs multiple filters. The configuration will depend on whether the system has series filters or parallel filters.

4). The fuel must travel from the tank to the injection pump. In some vehicles, a transfer pump plays this role. It works automatically to ensure that the injection system has a consistent supply of fuel. But in other vehicles, gravity and air pressure do the work of the transfer pump. They ensure that the fuel reaches the injection pump.

5). The fuel moves via lines which include heavyweight (between the injection pump and injectors), medium-weight (between the tank and injection pump), and lightweight lines.

diesel fuel in truck engine

6). As was noted above, a diesel engine works by sending atomized and pressurized fuel to the cylinders in the engine. The fuel injectors are responsible for delivering this fuel. They have to send it in precise amounts and they must maintain consistency to optimize power and fuel economy.

7). Where diesel engines are concerned, the way the fuel is injected matters. There is indirect injection where the fuel is first transferred to a pre-chamber where it mixes with some air before it moves on to the cylinder, leading to combustion.

You also have direct injection where the fuel goes directly to the combustion chamber. Then there is the common-rail injection, a form of direct injection in which injectors attached to a reservoir of high-pressure fuel work to ensure that the exact amount of diesel fuel is delivered at the right time.

8). The diesel fuel system doesn’t like water. Its presence within the injection system causes the steel parts to oxidize. Allowing water to infiltrate your system will lead to complications. especially where the governor and injection components are concerned.