🔍 Key Concepts

• Function of a pilot valve / pilot plunger in a hydraulic governor • How a proportioner or differential piston responds to oil pressure changes • Location and role of a balance piston in maintaining steady position

💭 Think About

• Look at what part #22 is connected to mechanically and hydraulically: does it directly move a valve, or does it respond to oil pressure from another control element? • Compare the shape and position of #22 with the other pistons in the lower-right section (#23–#26). Which one looks like the main servo piston and which looks like the small control element? • Ask yourself which component in this design would be responsible for sensing a small pressure difference and transmitting motion to a larger piston.

✅ Before You Answer

• Trace where pressure oil (red) and sump oil (orange) act on #22 versus nearby parts; the pilot plunger usually handles small flows and small motion. • Confirm whether #22 has a spring directly acting on it (common for a balance or differential piston) or if it is mainly a sliding element controlling ports. • Verify which element in the lower section is clearly the main servo piston; eliminate that choice, then match #22’s size and function to the remaining component names.