🔍 Key Concepts

• diesel engine piston cooling and heat transfer (how the crown gets rid of heat) • effects of fuel nozzle spray pattern on combustion and temperature distribution • relationship between mechanical clearances and thermal/impact stresses on the piston

💭 Think About

• Which conditions would cause the piston crown to run hotter than normal or have uneven temperature, leading to thermal cracking? • How could faulty fuel injection affect the flame pattern and local hot spots on the piston crown? • Does excessive piston-to-liner clearance mainly affect side thrust and wear, or does it directly load the crown in a way likely to crack it?

✅ Before You Answer

• For each option, decide if it could realistically cause overheating or high local stresses in the piston crown • Think about whether reduced heat transfer under the crown makes cracking more or less likely • Ask if a faulty nozzle spray can create hot spots on the crown that promote cracking