What is combustion in CI engine?

What is combustion in CI engine?

In CI engine the fuel is injected into combustion space after the compression of air is completed. • Due to excessively high temperature and pressure of air the fuel when injected in atomised form gets burnt on its’ own and burning of fuel is continued till the fuel is injected.

Which factors affect combustion in the CI engine?

The most important factors are explained below.

• 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.

How does CI engine works?

The compression ignition engine operating on liquid fuels, or in the dual-fuel mode, works on the principle of fuel being injected into a charge of compressed air and spontaneously ignited by the high temperature of the induced air by the heat of compression.

How the combustion is different in CI engine from SI engine?

Upper compression ratio in SI engines is limited by the auto- Upper compression ratio in SI engines is limited by the auto ignition temperature (SI: 8 to 12). Flame front in SI engines smooth and controlled. CI combustion is rapid and uncontrolled at the beginning. The valve timing in both CI and SI are similar.

What is delay period of CI engine combustion?

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 is delay period in CI engine?

Explanation: Delay period is defined as the time immediately following injection of the fuel during which the ignition process is being initiated and the pressure does not rise beyond the value it would have due to compression of air.

What are the factors affecting the delay period in CI engine?

Engine operating variables such as speed and load affect the ignition delay because they change the primary factors such as injection pressure, compression temperature, pressure and air velocity. It has been found that under normal running conditions, compression temperature and pressure are the major factors.

Which is better Si or CI?

The high temperatures achieved in CI engines cause the fuel to ignite. SI engines are high speed while CI engines are low speed. SI engines have a lower thermal efficiency than CI engines.

Is fuel pump used in CI engine?

The injection pump sends fuel under pressure to the nozzle pipes which carry fuel to the injector nozzles located in each cylinder head. Excess fuel goes back to the fuel tank. CI engines are operated unthrottled, with engine speed and power controlled by the amount of fuel injected during each cycle.

Which is better CI or SI engine?

6… Thermal efficiency: Due to lower compression ratio, maximum value of thermal efficiency is lower in an S.I engine compared to that of C.I. 7… Weight : S.I engines are generally lighter in weight due to their lower peak pressures as compare to C.I engines that are generally heavier, due to higher peak pressure.

Which engine is more efficient CI or SI?

CI engines have higher Thermodynamic Efficiency With a higher compression ratio in CI engines as compared to SI engines, CI engines have a higher thermodynamic efficiency since more work is done with each expansion stroke.

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

We have discussed the different stages of combustion in CI engine, those are ignition lag, the period of rapid combustion, the period of controlled combustion and the afterburning. If you have any further thoughts on this topic, let us know in the comment section below.

How does combustion take place in a compression engine?

Due to the heat of the air, the ignition of the fuel begins and combustion takes place. Due to the combustion of the fuel, hot exhaust gases produced that puts a very high thrust force on the piston and it moves downward. The piston rotates the crankshaft with the help of connecting rod.

Where does combustion take place in an IC engine?

Combustion is a chemical reaction which generates heat energy. The process of combustion is a very complex subject. This combustion process in an IC engine takes place in a homogeneous mixture or heterogeneous mixture based on the type of engine. In the previous article, we have discussed the Stages of combustion in SI engine.

What is the compression ratio of a CI engine?

In CI or compression ignition engine, in the compression stroke, only air is compressed at very high pressure and temperature. The compression ratio used is in the range of 12 to 120. The temperature of the air becomes higher than the temperature of the fuel which is diesel in the CI engine.