If the diesel engine fuel injection timing...

If the diesel engine fuel injection timing...

Question 1 of 270705eccefa2bacbc34ba4d478cc

If the diesel engine fuel injection timing is changed to delay the start of injection until the pistons are at top dead center, the engine will __________.

Question 1 of 27070

Q

If the diesel engine fuel injection timing is changed to delay the start of injection until the pistons are at top dead center, the engine will __________.

🔍 Key Concepts

• diesel fuel injection timing and what happens with late injection (after top dead center) • relationship between combustion start, piston position, and pressure development in the cylinder • how engine power and cylinder pressure change with early vs. late injection

💭 Think About

• Think about what happens to cylinder pressure if you start burning fuel when the piston is already beginning to move down instead of just before top dead center. • Which option matches the typical symptoms of retarded (late) injection timing in a diesel: power change, pressure change, or abnormal backfire? • Would late injection give combustion gases more or less time to expand on the power stroke, and how does that affect useful work on the crankshaft?

✅ Before You Answer

• Compare which choices are associated with very high peak firing pressures versus reduced effective pressure. • Consider whether backfire through the air intake is normally a diesel problem or more common with spark-ignition gasoline engines with intake manifolds. • Ask: with combustion starting late, is there more likelihood of lifting cylinder relief valves (excess pressure) or of not fully using the fuel energy for power?