What happens to air during the compression stroke of a Diesel engine?

What happens to air during the compression stroke of a Diesel engine?

• A. It is ejected from the cylinder
• B. It is drawn into the cylinder
• C. It is compressed and heated
• D. It remains unchanged

Answer: (C)

During the compression stroke of a Diesel engine, the air that was drawn into the cylinder during the intake stroke is compressed by the piston moving upwards. This compression occurs in a closed cylinder, which means the volume of air decreases significantly while the pressure increases. As the air is compressed, its temperature rises sharply due to the principles of thermodynamics, specifically the ideal gas law, which states that compressing a gas increases its temperature if no heat is lost to the surrounding environment. This high temperature is crucial for the operation of a Diesel engine because once the compression is completed, fuel is injected into the highly compressed and heated air, causing it to ignite spontaneously due to the elevated temperature. This process is what allows Diesel engines to operate efficiently and produce power. Thus, the primary result of this stroke is that the air is not only compressed but also heated significantly, playing an essential role in the engine's combustion cycle.

During the compression stroke of a Diesel engine, the air that was drawn into the cylinder during the intake stroke is compressed by the piston moving upwards. This compression occurs in a closed cylinder, which means the volume of air decreases significantly while the pressure increases. As the air is compressed, its temperature rises sharply due to the principles of thermodynamics, specifically the ideal gas law, which states that compressing a gas increases its temperature if no heat is lost to the surrounding environment.

This high temperature is crucial for the operation of a Diesel engine because once the compression is completed, fuel is injected into the highly compressed and heated air, causing it to ignite spontaneously due to the elevated temperature. This process is what allows Diesel engines to operate efficiently and produce power. Thus, the primary result of this stroke is that the air is not only compressed but also heated significantly, playing an essential role in the engine's combustion cycle.