Mechanical Flyweight Governor
A mechanical governor determines the fuel quantity by balancing the centrifugal force of weights driven by the engine against the force of a spring. As the speed rises the weights swing out and the fuel is cut back. It is the simplest and most widespread solution, but its regulation is not tight and droop is unavoidable.
The construction consists of three parts: the rotating weights, the setting spring and a linkage connecting them to the fuel rack or the throttle plate. The accelerator pedal or throttle lever in fact changes the preload of the spring; that is, the operator adjusts not the fuel directly but the governor's target speed.
- There is no sensor and no electronics; it works even if the supply is cut.
- Since the balance is established by spring force, when the load increases the new balance forms at a lower speed — that is why droop is inevitable.
- Wear of the weights and the joints leads over time to oscillation and delayed response.
The important point regarding AXI kits: this governor stays on the engine. The GS740 and GS740-3P move the mechanical lever that sets the governor's target remotely, by cable. That is, what is made electronic is the throttle lever, not the governor itself; the engine's speed safety and load response are still the responsibility of this mechanical arrangement.
Context in which this term is used: Electronic speed and throttle control on a diesel engine