Which of the following reflect the statement about air supply and burning fuel in a diesel engine as described in the material?

• A. Diesel engines supply only enough air to completely burn all the fuel.
• B. Diesel engines supply excess air to completely burn all the fuel.
• C. Diesel engines require less air than fuel ratio.
• D. Diesel engines require exactly stoichiometric air.

Answer: (A)

In this view, how much air is supplied is tied to how much fuel is injected, so that all the fuel can be burned with the air that’s available. The engine is described as delivering only enough air to support complete combustion of the injected fuel, rather than relying on extra air to drive the process. This reflects a situation where air is matched to the fuel so combustion can occur efficiently without an intentional excess of air. The other statements imply excess air or a different exact ratio, which isn’t what the material describes.