What are the four stages of combustion process?

An internal-combustion engine goes through four strokes: intake, compression, combustion (power), and exhaust.

What is normal combustion in CI engine?

Combustion in a spark ignition engine is termed normal if it is initiated by a timed spark plug and the air-fuel mixture (charge) is consumed solely by the propagating flame front which originated from the discharged spark and completely moves across the combustion chamber.

What is controlled combustion in CI engine?

(c ) Controlled or diffusion combustion phase: Once the fuel and air which is pre-mixed during the ignition delay is consumed, the burning rate (heat release rate) is controlled by the rate at which mixture becomes available for burning.

What is delay period in CI engine?

Abstract. The ignition delay in a diesel engine is defined as the time interval between the start of injection and the start of combustion. This delay period consists of (a) physical delay, wherein atomisation, vaporization and mixing of air fuel occur and (b) of chemical delay attributed to pre-combustion reactions.

What are the factors affecting combustion in CI engine?

The important factors

Molecular structure of fuel.
Temperature of self ignition.
Affect of high temperature and pressure after compression.
Temperature of combustion wall chamber.
Rate of burning.
Spark timing.
Spark intensity and duration.
Air-fuel ratio.

What are the two types of abnormal combustion?

There are three forms of abnormal combustion: Detonation, Pre-Ignition and Detonation of fuel before Ignition or (Pre-Ignition due to Detonation). The process of burning the fuel in the combustion chamber has always been the most misunderstood concept by people who modify engines and tune engines.

What are the four stages of combustion in a CI engine?

The combustion in a CI engine is considered to be taking place in four stages: i) Ignition delay period/pre-flame combustion. ii) Rapid combustion/uncontrolled combustion. iii) Controlled combustion and.

What is the delay period in a CI engine?

The delay period in the CI engine influence both engine design and performance ii) Rapid combustion: the period of rapid combustion also called the uncontrolled combustion, is that phase in which the pressure rise rapid.

Which is the second stage of the combustion process?

Rapid or uncontrolled combustion- This is second stage in which pressure rise is rapid since during delay period the fuel droplets have had time to spread themselves over a wide area and have fresh air around them. This phase extends from end of delay period to point of maximum pressure.

When does diesel fuel injection start in ci engine?

Then diesel fuel is injected in the combustion chamber under very high pressure about 120 to 210 bar. The temperature of this fuel is around 20° to 35° before TDC (Top Dead Center). Point A on the above graph shows the time at which diesel fuel injection starts. Then, the process of combustion in the CI engine starts.

Why is the last stage of combustion called after burning?

Practically, the burning of the fuel in the combustion chamber remains to continue during the expansion stroke. The main reason behind it is the reassociation of dissociated gases and unburnt fuel. Therefore, this last phase of combustion is called After Burning. These are the four different stages of combustion in CI engine.

What are the four stages of combustion process?