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Alcohols are unsuitable at diesel engine fuels because
- a)The cetane number of alcohol fuels is very low which prevents their ignition by compression
- b)The cetane number of alcohol fuels is very high which prevents their ignition bycompression
- c)None of these
- d)The cetane number of alcohol fuels is very low which prevent their ignition by combustion
Correct answer is option 'D'. Can you explain this answer?
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Alcohols are unsuitable at diesel engine fuels becausea)The cetane num...
The correct answer is option 'D': The cetane number of alcohol fuels is very low which prevents their ignition by combustion.
Explanation:
Alcohol fuels, such as methanol and ethanol, have been considered as potential alternatives to traditional fossil fuels due to their renewable nature and lower carbon emissions. However, they are not suitable as fuels for diesel engines mainly because of their low cetane number.
1. Cetane number: The cetane number is a measure of the ignition quality of a fuel. It indicates the ease and speed at which the fuel will ignite in a diesel engine when subjected to compression. A higher cetane number indicates better ignition properties.
2. Diesel combustion process: In a diesel engine, the fuel is injected into the combustion chamber, where it mixes with the compressed air. The heat of compression causes the fuel to self-ignite and burn, leading to the power stroke. This process is known as compression ignition.
3. Alcohol fuels and cetane number: Alcohol fuels, such as methanol and ethanol, have low cetane numbers compared to diesel fuel. Methanol has a cetane number of around 4-7, while ethanol has a cetane number of around 8-15. In contrast, diesel fuel typically has a cetane number of 40-55.
4. Ignition delay: The low cetane number of alcohol fuels leads to a longer ignition delay. Ignition delay refers to the time between the start of fuel injection and the start of combustion. A longer ignition delay can result in poor combustion, incomplete fuel burn, and reduced engine performance.
5. Compression ignition: Alcohol fuels with low cetane numbers require higher compression ratios or higher temperatures to achieve self-ignition. Diesel engines are designed to operate with a specific compression ratio, and altering this ratio for alcohol fuels may not be feasible or efficient.
6. Other factors: In addition to the low cetane number, alcohol fuels also have lower energy content compared to diesel fuel, which can further reduce their efficiency as engine fuels. They also have different physical properties, such as higher volatility and lower lubricity, which may require modifications to engine components and fuel systems.
In conclusion, the low cetane number of alcohol fuels, such as methanol and ethanol, prevents their ignition by combustion in diesel engines. This limitation, along with other factors, makes alcohol fuels unsuitable as direct replacements for diesel fuel in diesel engines.
Explanation:
Alcohol fuels, such as methanol and ethanol, have been considered as potential alternatives to traditional fossil fuels due to their renewable nature and lower carbon emissions. However, they are not suitable as fuels for diesel engines mainly because of their low cetane number.
1. Cetane number: The cetane number is a measure of the ignition quality of a fuel. It indicates the ease and speed at which the fuel will ignite in a diesel engine when subjected to compression. A higher cetane number indicates better ignition properties.
2. Diesel combustion process: In a diesel engine, the fuel is injected into the combustion chamber, where it mixes with the compressed air. The heat of compression causes the fuel to self-ignite and burn, leading to the power stroke. This process is known as compression ignition.
3. Alcohol fuels and cetane number: Alcohol fuels, such as methanol and ethanol, have low cetane numbers compared to diesel fuel. Methanol has a cetane number of around 4-7, while ethanol has a cetane number of around 8-15. In contrast, diesel fuel typically has a cetane number of 40-55.
4. Ignition delay: The low cetane number of alcohol fuels leads to a longer ignition delay. Ignition delay refers to the time between the start of fuel injection and the start of combustion. A longer ignition delay can result in poor combustion, incomplete fuel burn, and reduced engine performance.
5. Compression ignition: Alcohol fuels with low cetane numbers require higher compression ratios or higher temperatures to achieve self-ignition. Diesel engines are designed to operate with a specific compression ratio, and altering this ratio for alcohol fuels may not be feasible or efficient.
6. Other factors: In addition to the low cetane number, alcohol fuels also have lower energy content compared to diesel fuel, which can further reduce their efficiency as engine fuels. They also have different physical properties, such as higher volatility and lower lubricity, which may require modifications to engine components and fuel systems.
In conclusion, the low cetane number of alcohol fuels, such as methanol and ethanol, prevents their ignition by combustion in diesel engines. This limitation, along with other factors, makes alcohol fuels unsuitable as direct replacements for diesel fuel in diesel engines.
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Community Answer
Alcohols are unsuitable at diesel engine fuels becausea)The cetane num...
Cetane rating, also known as cetane number is
a measurement of the quality or performance of diesel fuel
. The higher the number, the better the fuel burns within the engine of a vehicle.
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Alcohols are unsuitable at diesel engine fuels becausea)The cetane number of alcohol fuels is very low which prevents their ignition by compressionb)The cetane number of alcohol fuels is very high which prevents their ignition bycompressionc)None of thesed)The cetane number of alcohol fuels is very low which prevent their ignition by combustionCorrect answer is option 'D'. Can you explain this answer?
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