🔍 Key Concepts

• heat transfer from the piston crown and why keeping the underside clean matters • how injection timing affects peak pressures and temperatures in the combustion space • effects of lubricating oil spray patterns on piston cooling and local hot spots

💭 Think About

• For each option, ask: would this condition tend to increase local temperature or thermal stress at the piston crown? How? • Consider how the piston crown actually gets cooled in a large diesel: which systems or conditions, if impaired or mistimed, would reduce cooling or increase thermal shock? • Think about whether these factors act independently or could all contribute to similar types of damage like cracking.

✅ Before You Answer

• Verify which of the listed conditions would raise temperature or create thermal gradients in the piston crown area. • Check your engineering knowledge: does dirty piston undersides make heat transfer better or worse? What happens then to metal temperature? • Confirm whether faulty oil nozzle spray affects just lubrication, or also piston cooling and temperature distribution.