Diesel Engine

" A “Start” light goes on. When you see it, you step on the accelerator and turn the ignition key to “Start.” Fuel pumps deliver the fuel from the fuel tank to the engine. On its way, the fuel passes through a couple of fuel filters that clean it before it can get to the fuel injector nozzles. Proper filter maintenance is especially important in diesels because fuel contamination can clog up the tiny holes in the injector nozzles. A diesel fuel filter. A diesel fuel filter. The fuel injection pump pressurizes fuel into a delivery tube. This delivery tube is called a rail and keeps it there under constant high pressure of 23,500 pounds per square inch (psi) or even higher while it delivers the fuel to each cylinder at the proper time. (Gasoline fuel injection pressure may be just 10 to 50 psi!) The fuel injectors feed the fuel as a fine spray into the combustion chambers of the cylinders through nozzles controlled by the engine’s engine control unit (ECU), which determines the pressure, when the fuel spray occurs, how long it lasts, and other functions. Anatomy of a fuel injector. Anatomy of a fuel injector. Other diesel fuel systems use hydraulics, crystalline wafers, and other methods to control fuel injection, and more are being developed to produce diesel engines that are even more powerful and responsive."