What is the purpose of the throttle pressure governor (TPG)?

The throttle pressure governor (TPG) is a critical component in fire apparatus that ensures the engine maintains a specific RPM to provide the necessary water pressure during operations. Its primary function is to automatically adjust engine RPMs in response to changes in water pressure demands. When water is being pumped, variations in flow can occur due to changes in nozzle pressure or flow requirements. The TPG compensates for these changes by adjusting the engine speed accordingly to maintain a set pressure, ensuring that firefighters have a consistent and reliable flow of water from the hose lines.

The automatic nature of the TPG allows for real-time adjustments without requiring manual intervention from the driver, increasing operational efficiency and safety during firefighting scenarios. This automated system is crucial because it helps prevent pressure drops that could impact firefighting efforts and ensures that the engine operates within its optimal performance range.