It’s no secret that the way cars run has changed vastly over the last few decades. One of the major improvements is found in the diesel engine. Diesel fuel is 25 to 30 percent more energy rich than gasoline and cars with diesel engines are up to 40 percent more efficient than their gasoline powered counterparts. Diesel engines run differently than gas engines because they use direct diesel fuel injection instead of port injection. How do these fuel injection systems work in your average car? We explore below…
1. Put the key in the ignition. As soon as you start turning the key, the process begins. Fuel is injected into the cylinders and heats the air as it does so because of the extremely high pressure. And since diesel is less combustible than gasoline, it sometimes needs a little more time to get going which is why some fuel injection systems have glow plugs that pre heat the engine chamber. These glow plugs are electrically heated wires that heat the combustion chamber and are super helpful during cold weather.
2. The fuel moves from the fuel tank to the engine by way of the fuel pumps. En route, the fuel passes through filters before it reaches the diesel fuel injectors that cleans it of any impurities. This is extremely important because the tiny nozzles in the diesel injectors can get clogged very easily.
3. The fuel is then pressurized into a tube (known as a rail) by a fuel injection pump. When injection pressures reach 30,000 psi, it creates a fine mist of fuel (controlled by the engine’s engine control unit) by squeezing the fuel through the tiny holes in the injector to help it burn more easily.
4. Everything finally comes together in the cylinders. And by everything, we mean the fuel, air and heat.
5. The combustion occurs and the engine fully fires up.
The main difference between diesel fuel injection systems and gasoline fuel injection systems is that the diesel one uses a direct approach versus the gasoline one which is a multiple step approach and leads to higher risk of malfunction.