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Alcohols are unsuitable as diesel engine fuels because
- a)The cetane number of alcohol fuels is very low which prevents their ignition bycompression
- b)The cetane number of alcohol fuels is very high which prevents their ignition bycompression
- c)The cetane number of alcohol fuels is very low And high which prevents their ignition bycompression
- d)None of the above
Correct answer is option 'A'. Can you explain this answer?
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Alcohols are unsuitable as diesel engine fuels becausea)The cetane num...
Ans. (a)
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Alcohols are unsuitable as diesel engine fuels becausea)The cetane num...
The correct answer is option 'A': The cetane number of alcohol fuels is very low, which prevents their ignition by compression.
Explanation:
1. Cetane Number and Ignition:
- The cetane number is a measure of the ignition quality of a fuel in a diesel engine.
- It indicates how easily a fuel ignites when subjected to compression in the engine cylinder.
- Fuels with higher cetane numbers have better ignition characteristics and tend to ignite more easily under compression.
2. Alcohol Fuels:
- Alcohol fuels, such as ethanol and methanol, have different properties compared to conventional diesel fuel (petrodiesel).
- While alcohol fuels can be used as spark-ignition (SI) fuels in gasoline engines, they are generally unsuitable as diesel engine fuels.
3. Low Cetane Number:
- Alcohol fuels have a very low cetane number, typically ranging from 4 to 15.
- This low cetane number indicates that alcohol fuels do not ignite easily under compression.
- The low cetane number is attributed to the chemical structure and properties of alcohol fuels.
4. Ignition Delay and Combustion:
- In a diesel engine, the fuel is injected into the combustion chamber at high pressure and temperature.
- The fuel then undergoes a delay period called the ignition delay before actual combustion occurs.
- During the ignition delay, the fuel vaporizes, mixes with air, and undergoes chemical reactions to initiate combustion.
5. Alcohol Fuel Limitations:
- The low cetane number of alcohol fuels results in a longer ignition delay.
- This longer ignition delay can cause several issues in a diesel engine, such as incomplete combustion, misfiring, and increased emissions.
- The longer ignition delay can also lead to higher peak pressures and temperatures, potentially causing engine damage.
6. Alternative Options:
- To use alcohol fuels in diesel engines, various modifications are required, such as engine design changes, fuel blending, and the use of ignition enhancers.
- These modifications aim to improve the ignition characteristics and overall performance of alcohol fuels in diesel engines.
In conclusion, alcohol fuels are unsuitable as diesel engine fuels because of their very low cetane number, which prevents their ignition by compression. This low cetane number results in a longer ignition delay, leading to issues such as incomplete combustion and increased emissions.
Explanation:
1. Cetane Number and Ignition:
- The cetane number is a measure of the ignition quality of a fuel in a diesel engine.
- It indicates how easily a fuel ignites when subjected to compression in the engine cylinder.
- Fuels with higher cetane numbers have better ignition characteristics and tend to ignite more easily under compression.
2. Alcohol Fuels:
- Alcohol fuels, such as ethanol and methanol, have different properties compared to conventional diesel fuel (petrodiesel).
- While alcohol fuels can be used as spark-ignition (SI) fuels in gasoline engines, they are generally unsuitable as diesel engine fuels.
3. Low Cetane Number:
- Alcohol fuels have a very low cetane number, typically ranging from 4 to 15.
- This low cetane number indicates that alcohol fuels do not ignite easily under compression.
- The low cetane number is attributed to the chemical structure and properties of alcohol fuels.
4. Ignition Delay and Combustion:
- In a diesel engine, the fuel is injected into the combustion chamber at high pressure and temperature.
- The fuel then undergoes a delay period called the ignition delay before actual combustion occurs.
- During the ignition delay, the fuel vaporizes, mixes with air, and undergoes chemical reactions to initiate combustion.
5. Alcohol Fuel Limitations:
- The low cetane number of alcohol fuels results in a longer ignition delay.
- This longer ignition delay can cause several issues in a diesel engine, such as incomplete combustion, misfiring, and increased emissions.
- The longer ignition delay can also lead to higher peak pressures and temperatures, potentially causing engine damage.
6. Alternative Options:
- To use alcohol fuels in diesel engines, various modifications are required, such as engine design changes, fuel blending, and the use of ignition enhancers.
- These modifications aim to improve the ignition characteristics and overall performance of alcohol fuels in diesel engines.
In conclusion, alcohol fuels are unsuitable as diesel engine fuels because of their very low cetane number, which prevents their ignition by compression. This low cetane number results in a longer ignition delay, leading to issues such as incomplete combustion and increased emissions.
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Alcohols are unsuitable as diesel engine fuels becausea)The cetane number of alcohol fuels is very low which prevents their ignition bycompressionb)The cetane number of alcohol fuels is very high which prevents their ignition bycompressionc)The cetane number of alcohol fuels is very low And high which prevents their ignition bycompressiond)None of the aboveCorrect answer is option 'A'. Can you explain this answer?
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