Diesel engine injection timing

In summary, the start of injection in an IC engine is affected by the speed of the engine. As the engine speed increases, the start of injection is advanced in order for the flame to properly propagate through the charge in the combustion chamber. In a spark ignition engine, the slow velocity of the flame front requires the spark to be significantly advanced at high RPM. In a compression ignition engine, the delay is not in the flame front but in the time to ignite after the start of injection, as well as the speed of sound in the fuel lines.
  • #1
Tekneek
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How does start of injection effected by speed of the engine? According to data, it seems for higher engine speed, the SOI (in terms of degree BTC) is higher.
 
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  • #2
Tekneek said:
How does start of injection effected by speed of the engine? According to data, it seems for higher engine speed, the SOI (in terms of degree BTC) is higher.
For an IC engine, the flame will tend to take a fixed time to propagate through the charge in the combustion chamber, so ignition/injection has to be advanced as the RPM increases.
 
  • #3
There is a distinct flame front in a spark ignition engine. The velocity of the flame front is quite slow so the spark must be significantly advanced at high RPM.

With a compression ignition engine, the fuel burns as it is injected. The delay is not so much in the flame front but in the time to ignite after the start of injection and the speed of sound in the lines from the injection pump to the injector.
 

What is diesel engine injection timing?

Diesel engine injection timing refers to the precise moment at which fuel is injected into the combustion chamber of a diesel engine.

Why is diesel engine injection timing important?

Diesel engine injection timing is crucial for efficient and effective combustion, which directly impacts the performance and emissions of a diesel engine.

How is diesel engine injection timing determined?

Diesel engine injection timing is determined by the engine's design and is typically controlled by the engine's electronic control unit (ECU). It can also be adjusted manually by mechanically altering the position of the fuel pump or injectors.

What factors can affect diesel engine injection timing?

The main factors that can affect diesel engine injection timing include engine speed, load, fuel quality, and ambient temperature. Changes in these factors can alter the ideal timing for optimum performance.

What are the consequences of incorrect diesel engine injection timing?

Incorrect diesel engine injection timing can result in decreased engine performance, increased fuel consumption, and higher emissions. It can also lead to engine damage and decreased longevity if not corrected.

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