Which of the following statements is true regarding diesel engine operation?

The statement regarding higher combustion temperatures leading to engine damage is indeed true in the context of diesel engine operation. Diesel engines rely on high compression to ignite fuel, generating significant heat within the combustion chamber. While some degree of heat is necessary for optimal performance, excessively high combustion temperatures can lead to several issues.

When combustion temperatures exceed the engine's design specifications, this can result in pre-ignition and detonation, risking severe damage to engine components such as pistons, cylinder heads, and valves. Additionally, elevated temperatures can promote the formation of nitrogen oxides (NOx), a harmful emissions pollutant, and can lead to problems such as engine knocking or misfiring.

Overall, maintaining controlled combustion temperatures is essential for preserving engine longevity and performance, confirming the importance of the correct thermal management of the diesel engine's operation.