What are the factors affecting knocking in SI engines?
Factors affecting Detonation or Knocking in SI engine:
- Compression ratio: The pressure and temperature at the end of compression increases with increase in compression ratio.
- Supercharging:
- Increasing inlet temperature:
- Increase in load:
- Advancing the spark:
- Flame travel distance:
- Spark plug location:
- Engine size:
What is meant by knocking explain the factors affecting it?
Knocking is violet gas vibration and audible sound produced by extreme pressure differentials leading to the very rapid rise during the early part of uncontrolled second phase of combustion. Factors affecting knock.
What is the phenomenon of knock in SI engine and the factors affecting knock in SI engine?
A) PHENOMENON OF KNOCKING IN SI ENGINE: Knocking is due to auto ignition of end portion of unburned charge in combustion chamber. As the normal flame proceeds across the chamber, pressure and temperature of unburned charge increase due to compression by burned portion of charge.
What is knocking in SI engine CI engine?
1] In an SI engine, knocking occurs after the mixture is ignited by the spark plug. In a CI engine, knocking occurs at starting of the combustion process. 2] Knocking causes due to low ignition lag.
What are the factor affecting detonation?
Factors which affects the detonation in spark ignition engine are temperature, time, density, composition.
Which of the following factors increase detonation in the SI engine?
Knocking or detonation is due to the auto-ignition of the end portion of the unburned charge in the combustion chamber. Factors affecting knocking in SI engine: Compression ratio:- Higher compression ratio will result in the higher temperature of the charge, the tendency to knock will increase.
What are the effects of knocking Mcq?
The knocking tendency in compression ignition engines for a given fuel will be Enhanced by decreasing compression ratio. In SI engine, knocking tendency increases with increase in compression ratio. In CI engine, knocking tendency decreases with increase in compression ratio.
Which of the following factors increases the tendency for knocking in CI engine?
In CI engine, the knocking tendency increases with a decrease in compression ratio. If the compression ratio is low in CI engine, there will not be enough temperature generation for ignition of the fuel-air mixture.
Which of the following factors decrease the detonation in SI engine?
Use of low octane fuel can eliminate detonation.
Which of the following factors decreases detonation in SI engines?
| Q. | Which of the following factor decreases detonation in SI engines |
|---|---|
| B. | advancing the spark timing |
| C. | larger sized engine |
| D. | fuels with high s. i.t. |
| Answer» d. fuels with high s. i.t. |
Which of the following factors would increase the probability of knock in CI engines?
3. Low inlet pressure and temperature reduce knocking tendency in SI engines but increase the knocking tendency in CI engines.
What is the effect of humidity on knocking?
Clearly, an increase in the water content in air substantially increases the Knock Limited Spark Timing (KLST), as is known in practice. From this we conclude that the presence of water vapor increases the resistance to knocking of the gaseous fuel/air mixture substantially.
Which of the following factor decreases detonation in SI engine?
What are effects of knocking Mcq?
Which of the following factor decreases the detonation in SI engine?