Technology is ever growing and so is the world of automotive. Ignition system of all the automotive machines be it diesel or gasoline powered have been improved a great deal. In diesel powered machines, the most important component and the datum of how fuel efficient the machine is, is the type of fuel injectors it has. Vehicle manufacturers have dedicated departments dealing with diesel injection systems and all other components related to it. The performance of each and every diesel engine is greatly influenced by the type of injection system it has installed. The main function of a diesel injection system is delivering fuel to the combustion chamber of a diesel engine, this is not only the function it has because the way diesel is delivered to the cylinders determines the efficiency and the amount of energy that will be extracted from the fuel and delivered to the vehicle through the function and actuation of the crank shaft which forms the main prime mover of all the other components of the engine. Performance, gases emissions and voice characteristics are some of the parameters determining or arising from the type of injection system.
Unlike in petrol injection systems where the ignition of air-fuel mixture is ignited by a spark, diesel injection is operated at extremely high pressures since the ignition of this mixture is as a result of high pressure thus, flash point temperature. This fact implies that these systems are subjected to very high stresses hence the system materials and designs should be put in such a way that these effects are countered and that the engine performance is made stable and in a sound condition. Since the major function of a fuel injection system in an engine is to actuate delivery of diesel for combustion, the air-fuel mixture must be pumped through a nozzle at the exact proper time which implies that timing factor must be controlled and that the correct amount of air-fuel mixture must be delivered in order to meet the power requirement of the engine as designed by the manufacturer therefore, injection calculation and metering must be controlled.
In addition to this it is not enough to just deliver the controlled amount of fuel at the controlled timing aspect accurately since there are so many other things hindering the actuation of these two aspects. The following are some of the crucial aspects which are the additives to the main function of diesel injection systems.
Atomization of fuel is the process of making liquid fuel into a vapor like substance which increases the surface area for air-fuel mixing hence, making it more efficient. This is another function of fuel injection system. A well designed diesel injection system should be able to atomize all the fuel available at a give period of time at any instance and enable a good and uniform combustion.
While complete evaporation and fuel atomization is critical, sufficient amount of oxygen in the fuel is another very important aspect since it is oxygen that is needed during combustion. A good bulk mixing ensure high fuel efficiency and less problems as fully combusted fuel does not cause problems in the engine since there will not be any remains of fuel in places where they are not supposed to be. It is therefore, a dedicated function of fuel injection systems to ensure that there is enough combustion air in the chamber at any ignition phase of the engine cycle. A well designed system ensures this aspect at each time and sensors are fitted for when there is a problem with the system and no enough air is entering the ignition chamber.
This is closely related to bulk mixing where the fuel amount in air found in the ignition chamber should be utilized in order to enable a proper combustion and therefore, high engine efficiency.
Engine power and efficiency depends on how efficient the systems deliver fuel and how much fuel is delivered per unit given time. In order to ensure accurate performance of this system electronics have been incorporated to enhance sensor technology and variable valve timing in order to ensure that there is fuel at the exact time it is required and therefore, injection systems for diesel are a very important component in the automobile industry.