(a) Why flyweights are driven at a higher rotational speed than the engine

The operation of flyweights in a governor relies on the principle of centrifugal force, which governs their outward movement from the centerline. The centrifugal force is given by:

$$F=m\omega^2r$$

Where:

• m = mass of the flyweights
• ω = angular velocity of the flyweights
• r = radius of rotation

To enhance the sensitivity of the governor (the ability to respond accurately to changes in engine speed), the centrifugal force must be increased. Since increasing the mass (m) or radius (r) would lead to larger and less practical governor designs, the angular velocity (ω) is increased instead.

Flyweights are driven at a higher rotational speed than the engine using step-up gears. This increases the centrifugal force significantly without increasing the size of the governor, thus improving sensitivity.

(b) How Dead Band Effects Are Reduced:

The dead band is the range of speed change within which the governor does not act to correct throttle movement. This is caused by friction, poor lubrication, or mechanical resistance in the governor’s components.

• Use low-friction components and ensure proper cleaning and maintenance of linkages and sleeves.
• Apply the correct grade of low-viscosity oil to reduce drag and ensure smooth operation.
• Use step-up gears to increase the rotational speed of the governor for quicker response.
• Ensure all parts are designed and aligned to minimise mechanical resistance.

Hunting occurs when the governor overcorrects or undercorrects changes in engine load, leading to fluctuations in engine speed. This is often caused by excessive sensitivity, usually due to insufficient droop.

• Increasing the droop (a slight reduction in speed for an increase in load) reduces over-sensitivity.
• Clean and properly lubricate linkages and sleeves to allow smooth movement.
• Low-viscosity oil ensures efficient operation.
• Purge the system if necessary to avoid erratic behaviour.
• Use a conical spring to provide better performance and stability in the governor's operation.

The output torque of a governor is critical for effective throttle control and can be increased through the following methods:

• Raise the rotational speed of the flyweights using step-up gears.
  • Since torque is calculated as Torque = Force x Perpendicular distance, increasing centrifugal force directly amplifies torque.
• Ensure high-quality oil is used, and regularly clean filters. Renew oil at recommended intervals to maintain optimal hydraulic pressure.
• Amplify the signal from the governor using a servo mechanism, which increases output torque without overloading the system.
• Adjust lever arms to maximise the perpendicular distance for torque generation.