Why do Heavy Trucks Use Diesel Instead of Regular Gasoline?



Most of us drive cars powered by gasoline. If you have ever rented or owned a heavy truck, however, you might have had to pay attention to that green gas cap that tells you to fill that tank with diesel rather than gasoline. Add the wrong fuel, and you end up with a very costly breakdown!

Why the difference? With gasoline the new standard, why do large trucks, tractors, and other pieces of heavy equipment still use this seemingly outdated, high-emission fuel? Why not switch to gasoline?

Pacific Pride reveals the reason trucks use diesel instead of gas

The heavier the load an engine has to pull, the more you have to worry about torque.

Torque is the twisting force an engine is able to deploy to displace the cylinders. A heavy object at rest is much harder to get moving. The more force the engine produces, the heavier the load it can pull.

Diesel engines produce much more torque at lower RPM. The lean mixture produces more energy than gasoline. At idle, the engine gets almost no fuel.

Open the throttle up just a little, and this mixture provides the engine with a lot of fuel. You end up with high torque at very low throttle, which these big vehicles need to get moving and stay moving.

A gasoline engine requires a more specific ratio of reactants, resulting in a richer fuel mixture. This is fine for smaller vehicles, but a larger truck will need an exponentially larger, fuel-guzzling gasoline engine to move it effectively. By offering more torque with less throttle, a diesel engine ends up burning far less to move the same vehicle, making them cheaper and better for the environment to fuel.