🔍 Key Concepts

• Relationship between engine load and exhaust temperature in diesel engines • Effect of fuel injection timing (early vs late) on combustion temperature • How compression ratio generally affects starting, power, and combustion temperature

💭 Think About

• Think about what happens to combustion temperature and exhaust gas temperature when an engine is asked to do more work than it should. • Consider whether early injection gives fuel more or less time to burn before the exhaust valve opens. • Ask yourself: would a very light load make the exhaust hotter or cooler compared to normal operation?

✅ Before You Answer

• Be clear on how increased load changes cylinder pressure and temperature during combustion. • Review whether early vs late injection tends to raise peak cylinder pressure but may increase or decrease exhaust temperature. • Remember what a low compression ratio mainly affects (starting, efficiency, smoke), and whether it is commonly associated with abnormally high exhaust temperatures.