What are the various factors influencing the flame speed in SI engine?

Duration depends on the following factors: Fuel: Chemical nature of fuel High self-ignition temperature of fuel longer the ignition lag. Rate of flame propagation affects the combustion process in SI engines. Higher combustion efficiency and fuel economy can be achieved by higher flame propagation velocities.

What are the factors affecting combustion in an IC engine?

Factors governing combustion in engines :

• Mixing of fuel and air.
• Compression ratio.
• Spark timing (For SI)/ self ignition temperature (For CI)
• Turbulent mixing.
• Load on engine.
• Engine speed.
• Fuel characteristic like octane number (For SI)/ cetane number (CI)

What is the main factor that controls the flame burning velocity in a spark ignition engine?

The spark-ignition engine combustion rate is primarily dictated by the chamber geometry, the turbulent flame entrainment rate, and the laminar flame speed of mixture burn-up [2, 3]. The combustion flame propagation, distribution and disappearance can be simplified by a parametric model.

What are the various factors that affect the flame speed explain any 3 with justification?

The temperature and pressure of the fuel/air mixture, ❑ The concentration of residuals , ❑ The chemical reaction rate.

How does the flame speed affect the performance of combustion chamber?

The higher the flame speed is, the closer is the overall combustion process to the TDC, resulting in higher average temperature and pressure.

What is flame front in IC engine?

Laminar flame speed is the velocity at which the flame propagates into quiescent premixed unburnt mixture ahead of the flame. Flame is the result of a self sustaining chemical reaction occuring within a region of space called the flame front where unburnt mixture is heated and converted into products.

What are the factors that affect the combustion chamber?

Table of Contents:

• What Are The Factors Affecting Combustion Chamber Design?
• Temperature Of Gases.
• Temperature Distribution.
• Combustion.
• Carbon Deposits/Coking.
• Combustion Chamber Pressure.
• Pollutants.
• Volume And Weight.

What is the most important single factor affecting flame speed?

There are several factors which affect the flame speed, to a varying degree, the most important being the turbulence and the fuel-air ratio.

What is flame quenching in IC engine?

However, as the flame approaches combustion chamber walls, more and more heat is lost from the flame to the walls. Due to heat transfer from the flame to the walls, temperature of the reaction zone gets lowered that slows down combustion reactions reducing heat release rate. This phenomenon is known as flame quenching.

Which of the following factors would increase the probability of knock in the CI engines?

3. Low inlet pressure and temperature reduce knocking tendency in SI engines but increase the knocking tendency in CI engines.

What are the factors that affect the flame propagations in engines?

The factors which affect the flame propagations are 1. Air fuel ratio 2. Compression ratio 3. Load on engine 4. Turbulence and engine speed 6. PHENOMENON OF KNOCKING IN SI ENGINE 7.

Why do engines with higher compression ratios have higher flame speeds?

Increased compression ratio reduces the clearance volume and therefore increases the density of the cylinder gases during burning. This increases the peak pressure and temperature and the total combustion duration is reduced.Thus engines having higher compression ratios have higher flame speeds.

What determines the flame speed of a fuel?

The flame speed determines the ability of a fuel to undergo controlled combustion without detonation . Flame propagation is a result of both the reaction rate and the transposition rate.

How does the velocity of the flame affect the ignition time?

The velocity of the flame decreases the tendency to detonate, though the pressure and temperature increase at the end of compression. In other words, increase in these two factors leads to decrease the delay period of the initial reactions there by increasing the tendency to detonate.