Exercise 5

Question 1

Describe the direct injection for a diesel CI-injection for full burning to occur

Answer 1

1, As there is a high pressure drop across the nozzle opening, the fuel is injected in to the cylinder in high speed.
2, Atomization of the liquid fuel in to droplets.
3, Air is entrained (fancy for mixed) in to the fuel.
4, Fuel evaporates from fuel-droplet surface. The fuel damp mixes with air.
5, Some of the fuel- air ignite spontaneous.
6, Now that the “premixed” fuel-air (the portion of the fuel that evaporates) mixes with oxygen. The rest of the fuel burns with air as the flame from the mixed region creates enough heat to combust the rest.