It is known that if the injection period is increased far beyond certain limits some fuel may not get the time to burn which is uneconomical and creates some pollution problems. I am asking if this has come into consideration by engine developers.
Depending on the point of operation, a certain amount of fuel has to be injected into the cylinder to bring in the required mass of energy carrier. An efficient combustion in the diesel process is supported by a high degree of atomization during the injection process. This is achieved by multi-hole injectors in combination with high injection pressurs. High injection pressures lead to reduced injection timing. Modern injection systems enable multiple injection for influencing the combustion. In general, the higher the injection pressure, the shorter the combustion and the better the combustion efficiency, including fuel consumption and exhaust emissions. Regarding exhaust emissions formation, the reactions are more complex, but it can be statet, that a high injection pressure supports the lowering of e.g. particulate emissions.
Kind regards,
Mario
But the injection period is also controlled by the load and speed demand. The design of the fuel injection system also contribute to this. I wonder if the start of injection could have an effect because we need to look for an optimum injection timing and this I assume is not the same for all engines.
The start of injection depends on the type of injection (direct or indirect injection), the design of the combustion chamber including piston, and several combustion process related parameters, e.g. cylinder pressure, temperature, kinetic energy of fresh charge, etc. For a specific engine, the injection timing can be simulated by use of 3-dimensional fluid dynamics simulation, e.g. with the software AVL Fire or Fluent.
Kind regards,
Mario
Yes Abhijit this what I am looking for. Do you have such a map? Have you reached one optimum injection timing for all conditions of load and speed or is it different for different conditions ? What about using an engine of a different size?
I think optimum injection timing and pressure can be obtained by changing timing and pressure at different speed and loads. We are also trying on this. We have open ECU CRDI diesel engine and got a random calibrated map by supplier. Now we are looking for a single map for all speeds and loads if possible. For that first we are making speed constant and varying load, simultaneously changing injection timing and pressure and check for smooth running of engine. Further we are making graphs of pressure v/s crank angle and HRR v/s crank angle to get the optimized pattern. We are on the way and trying to reach for one optimized calibrated map for all speeds and loads. Currently we are looking to get optimized map for constant rpm of 2000.
Mr. Kamal if you want suppliers calibrated map please mail me on [email protected] and plz write research gate reference on subject line.
Thanks
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