🔍 Key Concepts

• Fuel blocking / shutdown circuits in low-speed diesel engines • The role of a shutdown servomotor (A) connected to the fuel rack • How an emergency stop valve/button (D) typically acts on control air to dump pressure and move a spring-loaded device to the shutdown position

💭 Think About

• Look at the labels and physical connections: what does the title Fuel Blocking Valves Group tell you about the main purpose of this circuit? • Trace the blue control-air line from the 7 bar supply: which component directly controls whether pressure is held on, or vented from, the shutdown servomotor at A? • Compare the functions: which option talks about normal reversing/camshaft shifting, and which options talk about removing air so the shutdown servomotor can relax and close the fuel rack?

✅ Before You Answer

• Identify which device is spring‑loaded and therefore will move to the fuel‑off position when air pressure is removed. • Confirm whether A is supplying a signal to the rest of the system, or simply receiving air to move the fuel rack. • Check how valve D is drawn: does it look like a manually operated emergency stop that connects the servomotor line either to supply air or to exhaust/vent when pressed?