Combustion knock will most likely occur as a...

Question 1 of 270705eccefa2bacbc34ba4d47799

Combustion knock will most likely occur as a result of using a fuel with __________.

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Question 1 of 27070

Q

Combustion knock will most likely occur as a result of using a fuel with __________.

🔍 Key Concepts

• combustion knock in diesel engines vs normal smooth combustion • the meaning of cetane number and what high vs low values indicate • the relationship between ignition delay and pressure rise in the cylinder

💭 Think About

• Think about what happens inside the cylinder when fuel injection is delayed and then suddenly burns all at once. Which fuel property would make that more likely? • For diesel fuel, does a high cetane number mean it ignites easily/quickly, or slowly/reluctantly? How would that affect knocking? • Consider whether high volatility mainly affects starting/evaporation, or the timing and violence of combustion.

✅ Before You Answer

• Be clear on the definition: cetane number measures ignition quality of diesel fuel (tendency for quick, smooth ignition). • Remember that long ignition delay lets more fuel accumulate before it burns; when it finally lights off, pressure rises very fast and can cause knock. • Check which choice corresponds to poor ignition quality with longer delay, since that condition favors knocking.