The end of fuel injection in a port-and-helix...

The end of fuel injection in a port-and-helix...

Question 1 of 270705eccefa2bacbc34ba4d478a7

The end of fuel injection in a port-and-helix metering pump can be controlled by __________.

Question 1 of 27070

Q

The end of fuel injection in a port-and-helix metering pump can be controlled by __________.

🔍 Key Concepts

• Port-and-helix fuel injection pump operation – how rotation of the plunger changes when fuel stops flowing to the injector • Function of the helix and spill ports – how exposing or covering spill/return ports affects fuel pressure in the delivery line • Role of the delivery valve – what it does after injection vs. what actually determines the end of injection

💭 Think About

• In a port-and-helix system, ask yourself: what mechanical event makes the pressure to the injector drop suddenly so that injection stops? • Which component (helix/ports vs. delivery valve) is primarily used for metering the quantity of fuel, not just sealing the line? • When the plunger moves upward and rotates, what happens when the helix reaches the spill port in the barrel?

✅ Before You Answer

• Be clear on which action causes fuel to spill back to the low-pressure side, instantly ending injection. • Identify which option describes loss of pressure in the barrel rather than just closing a check valve. • Verify: in a port-and-helix pump, the plunger helix alignment with the barrel ports is what changes the effective stroke and ends injection.