Factors Influence CI Engine cycle

The following are the factors that influence the compressed ignition (CI) engine cycle:

1. Non-constant pressure combustion of the fuel
2. Dissociation
3. Blow-down losses
4. Pumping losses

1. Non-constant pressure combustion of the fuel:

• In the basic CI engine air cycle, the heat was assumed to be added to the cycle at constant pressure.
• In the case of high-speed engines, it approaches a constant volume addition of heat process.
• The low-speed engines manage to approximate the constant pressure process.
• On the other hand, the high-speed engine diagram tends toward the SI engine diagram, which has a much more pointed peak.

2. Dissociation:

Dissociation apparently exists in the combustion process of the CI engine but does not have as pronounced an effect as it does in the Si engine. This is due to the heterogeneous mixture in the combustion chamber and the excess air present. Both of these factors tend to reduce dissociation by lowering the overall temperature of the combustion gases.

3. Blow-down process:

The blow-down losses of the four-stroke cycle CI engine are similar to those of the SI engine. However, the two-stroke cycle engine exhibits an appreciably more significant loss than the four.

4. Pumping loss:

• The pumping loss in a four-stroke cycle CI engine doesn’t exist, but it is relatively small because the airflow is not throttled for the part.
• Load operation.