Diesel engines use a fuel injector to deliver fuel to the cylinders. The injection process is different from gas engines, which uses a carburetor or a port injection system. While a carburetor mixes air and fuel before the former makes it to the cylinder, a port injection system mixes fuel before the intake stroke.
Diesel engines use a direct injection system that inserts fuel directly into the motor cylinders. A diesel engine injector is the most complicated component and can be in different areas.
The Internal Injector Process
A good injector can withstand the pressure and temperature in the cylinder while delivering fuel efficiently. The diesel delivers as a fine mist that circulates in the engine cylinder for even distribution. Some engines use a pre-combustion chamber, special induction valves, and other devices to improve the ignition and combustion process.
The compression process is compromised when the diesel engine becomes cold since the air cannot reach a high enough temperature for the fuel ignition to occur. Some diesel engines solve this problem with a glow plug—an electronically heated wire that heats the combustion chamber.
Glow plugs do an excellent job of raising the temperature when the engine is too cold, which quickly achieves the ideal temperatures for ignition.
Alternative Injector Technology
Modern diesel fuel injectors also make use of computer chips, particularly ECM communications. These chips regulate fuel spraying, air intake, engine coolant, RPM, and other functions within the process. These types of engines do not include a glow plug.
The computers chips work with an elaborate number of sensors to measure ambient air temperature and delay engine timing in cold weather. This process allows the injector to dispense fuel when the weather is warmer, for more efficient compression.
It is worthy to note that smaller engines don’t use advanced computer chips to solve the starting problem brought about by cold weather. Engine cylinders also have unique supply lines from the fuel tank for passing diesel into the injector. Each cylinder features a filter that removes any impurities before the injection process starts.
The Pulse Width Process
An integral part of diesel fuel injectors is the solenoid, which opens to pass the vaporized fuel. The process is called pulse width, and each cylinder receives a different fuel amount as calculated by the ECU. The ECU also ensures the combustion process reaches an appropriate stoichiometric ratio, which is the proportion between air and fuel at which combustion begins.
Part of this ecosystem is a small pump that forces air into the injector. The air ends up mingling with diesel, so the pump should be able to withstand increased amounts of pressure and high temperatures.
A small nozzle is used to spray diesel into the combustion chamber. The nozzle features a sequence of holes to ensure even distribution within the cylinder.
The second valve sucks air from the combustion chamber and mixes it with vaporized diesel to further intensify the combustion process. The exhaust valve then channels out emissions from the combustion chamber.
The remaining fuel flows through the return fuel line to the tank.
Do you have any questions about diesel fuel injectors or other diesel-related questions? Contact the friendly professionals at your nearest Taylor Diesel today.