Despite the differences between diesel and gasoline fuel, the primary differences lie in the engines themselves. Whereas gasoline engines use spark plugs that ignite the fuel when it is in the combustion chamber, diesel engines with an injection pump automatically inject a certain amount of fuel into heated, high-pressured air that automatically ignites it. Diesel is a fuel made from lesser-grade petroleum products. While gasoline requires a large amount of crude oil processing to be created, diesel does not need as much processing, which was one reason its emission are sometimes dirtier than those of gasoline. Modern diesel engines use computer diagnostics and very clean systems that make diesel use even cleaner than gasoline, thanks is large part to the injector system. Traditionally, diesel engines provide less horsepower but more torque than gasoline engines. This means that gasoline burns more easily and quickly, and provides force needed to rev up quickly and reach a certain number of miles per hour. Diesel engines, on the other hand, are excellent for pulling loads over long distances, which is why many trucks have diesel engines.
The first types of injection pumps were inline, meaning that there was a pump and plunger unit connected to each engine cylinder. The fuel was inserted into the pump unit, with one end opening to the combustion chamber and the other housing the plunger. The plunger moved back and forth: with the backward stroke, it opened a valve that let the fuel in, and in its forward stroke it generated a large amount of force that propelled the fuel into the combustion chamber. The heated air and pressure in the chamber instantly ignited the fuel, so that no spark plugs were needed.
Distributor Injection Pumps
The more modern distributor injection pumps use only one injection pump, but it is rotated to meet each combustion chamber as needed, and comes with additional valves that control exactly how much fuel is inserted into the pump chamber. By electronically controlling the fuel used with each injection, the maximum amount of fuel can be saved. There are also modern gasoline engines that use the fuel injection system for a similar end. By avoiding the use of spark plugs and controlling fuel use, these engines also work to save energy, this time in the form of use less gasoline.