Governor Definition Engine
- A governor is also the mechanical device that controls the average speed of an engine when there is a variation in load. It maintains the engine speed within specified limits regardless of load variations. It is basically a speed-controller device that is used to measure and control machine speed despite load variations.
- The governor changes the configuration when the load on the engine changes and controls the fuel supply accordingly.
- It acts as a cruise control mechanism that drives the engine at the set speed limit of your selection, even if the load varies.
- It detects changes in load and adjusts the throttle accordingly. Unlike a flywheel, it can control speed but is unable to store and supply energy when needed.
- It is used in most engine-driven applications such as tractors, lawnmowers, automobiles, etc.
- A governor is termed isochronous when the equilibrium speed is constant for all radii of rotation of balls within working range. For the slightest change of speed due to a change in load, such a governor would jump from one extreme position to another. Thus, an isochronous governor is oversensitive.
Equation of Speed
- From the equation above, it can be observed that for every configuration, there are maximum and minimum limits of speed between which the speed varies without change of the configuration.
- From the figure, for a given height h, the speed can vary between N 1 and N 2 without a change of the configuration.
- The maximum speed at which the governor will rotate is NA when the sleeve is in the highest position and has a tendency to ascend, and the minimum speed is NB when the sleeve is at the lowest position and has a tendency to descend.
Porter Governor Working
- When the engine load is reduced, the engine speed will increase suddenly, and the spindle speed will also increase.
- As the spindle speed increases, the two fly balls also move faster around the spindle. The centrifugal force will push balls outward, moving the ball upward.
- As the ball moves upward, the arms also move upward, and the sleeve attached to the lower part of the also moves upward.
- The upward movement of the sleeve activates the throttle valve through a mechanism attached to the sleeve to reduce the fuel supply to the engine.
- A decrease in fuel supply reduces speed. Therefore speed is maintained.
- In the second case, the engine speed decreases when the engine load increases.
- As the engine speed decreases, the spindle speed also decreases, and the centrifugal force in the balls decreases.
- Therefore balls come down with arms.
- As the arms move down, the sleeve attached to the arm also comes down, and this activates the throttle valve, which increases the fuel supply.
- Due to the increase in fuel supply, engine speed also increases.
Porter Governor Construction
- Porter governors have two fly balls, which are attached to the arms of the porter governors. Both these arms are taped on top of the axis.
- It is powered by a spindle engine. The arms parts are attached to the central sleeve just above the fly balls.
- This sleeve moves up and down according to the speed of the balls.
- The spindles have stoppers in place to limit the vertical movement of the axle.
- This sleeve is a heavy central load. The sleeve speed controls the opening and closing of the throttle valve.
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