🔍 Key Concepts

• Common rail fuel system design and how pressure is generated and maintained • Difference between pressure generation and fuel metering/timing • Role of a pressure control / bypass / relief valve in hydraulic systems

💭 Think About

• Ask which component or factor can keep fuel pressure in the rail nearly constant over a range of engine speeds and loads • Consider which options affect how much fuel is injected versus which actually control rail pressure itself • Think about what would happen to pressure in the rail when demand drops suddenly—what part of the system handles that extra pressure?

✅ Before You Answer

• Identify which choices directly change rail pressure, not just injection quantity or timing • Eliminate any option that mainly controls engine power output but not the hydraulic pressure in the rail • Verify which component is typically used in hydraulic systems to bleed off excess pressure and stabilize it