Question 1 of 27070
Q
When the opening pressure of a diesel engine fuel injector is greater than that specified by the engine manufacturer, which of the following problems can be expected?
A
Quantity of fuel injected tends to be decreased.
B
Quantity of fuel injected will always be increased.
C
Start of injection tends to be advanced.
D
Duration of injection will always be greater.
Question 1 / 270705eccefa2bacbc34ba4d47846
Question 1 of 270705eccefa2bacbc34ba4d47846

When the opening pressure of a diesel engine fuel injector is greater than that specified by the engine manufacturer, which of the following problems can be expected?

Back
Back
Back
Question 1 of 27070
Q

When the opening pressure of a diesel engine fuel injector is greater than that specified by the engine manufacturer, which of the following problems can be expected?

If the question has a related picture, it will appear here.

🔍 Key Concepts

• Effect of higher injector opening pressure on when fuel begins to flow (timing of start of injection) • Relationship between injection pressure and fuel quantity through a nozzle orifice over a fixed cam stroke • Difference between **"tends to" (may/likely) vs. "will always" (guaranteed) wording in answer choices

đź’­ Think About

• If the spring is adjusted so that the injector needs more pressure to open, what happens first: does fuel start earlier, later, or at the same crank angle? • With the same cam profile and same pump stroke, if the injector opens later and closes at the same time, what happens to the total amount of fuel that can pass? • Look closely at answers that say "will always" — in real machinery, how often can we guarantee something under all operating conditions?

âś… Before You Answer

• Compare start of injection timing when opening pressure is higher vs. when it is correctly set. • Decide whether injection duration is likely to become longer, shorter, or unchanged when the nozzle opens later but closes at roughly the same point. • Think about whether any choice that says "will always" can be strictly true given variations in speed, load, and fuel system condition.