How Does Engine Governor Works?

A cruise control system and a governor system are similar. The speed of your lawnmower or other outdoor power equipment is maintained by it. Properly calibrated Briggs & Stratton governors maintain a constant speed regardless of engine load, or the amount of work the engine has to do.

The engine load of a lawnmower may be impacted by grass height or slopes. The load on a tiller engine may be influenced by the tine depth, while the thickness of the branches can have an impact on the load on a chipper.

Every time your lawnmower went over a thick area of grass, you would have to manually adjust the throttle in the absence of a governor. By recognizing variations in the load and modifying the throttle accordingly, a governor takes care of the work for you.

Well, in this reading, I’ll be exploring Engine Governor is, its application, diagram, types, advantages and disadvantages & How it works.

Let’s Get Started!

What Is Engine Governor?

A governor, also known as a speed limiter or controller, is a tool used to gauge and control a machine’s speed, such an engine. A prime example is a reciprocating steam engine’s centrifugal governor, sometimes called the Watt or fly-ball governor. It modifies the steam input flow to control the engine’s speed by using the inertial force acting on revolving weights that are powered by the output shaft of the engine.

An engine governor is a mechanism that, independent of load, automatically keeps the rotating speed of an engine or other prime mover within acceptable bounds. A typical governor modifies the rate at which fuel is supplied to an engine in order to control its speed.

A regulating force, generally delivered by springs, prevents the two weights from flying outward as they rotate around a spindle that is propelled by the prime mover. Almost all governors rely on centrifugal force to operate.

As speed increases, the regulating force is overcome and the masses travel outward. This movement is transferred to the valves that provide fuel or working fluid to the prime mover. The rotating masses are balls with link arms fastening them to a vertical spindle; the weight of the balls acts as the regulating force.

If the engine’s load is reduced, the engine will run faster, the ball M will exit, member C will slide up the vertical spindle and let in less steam, which will slow down the engine. The reverse outcome will occur if the load is increased. Gas, water, or steam flow to different kinds of turbines and petrol flow to internal combustion engines are both controlled by modern governors.

How Does Engine Governor Works?

The working principle of governor is based on the equilibrium between the governor spring and flyweights. At the intended engine speed, the chosen spring and flyweight combination guarantees that spring and centrifugal forces are balanced.

Fuel supply via the lever system is reduced as a result of the flyweights’ increased centrifugal force in response to speed increases. On the other hand, as the speed drops, the control rod moves to boost the rate of fuel supply and bring the speed back up to the intended level.

Governors are made to run at all speeds automatically, even at idle and at the lowest possible level. They are often included in designs for fuel injection pumps. For efficient functioning, governors for diesel engines need to have a few specific features.

Centrifugal force is the principle underpinning the operation of governors, which are typically composed of flyweights or spinning masses powered by the engine’s output shaft.

These governors adjust the control mechanisms to regulate speed in response to variations in the centrifugal force exerted on the flyweights due to engine speed variations. The flyweights are essential for adjusting speed, as they are identical in weight and arranged in opposition to one another.

Centrifugal governors have advantages such as their strong and uncomplicated design, lower cost, ability to handle applications quickly, and automatic adjustment without the need for external power sources. However, they also have disadvantages such as longer reaction times and being sensitive to external influences like temperature and friction.

Inertia governors, also known as flywheel governors, operate on the basis of inertia. They use a weighted lever or pendulum mechanism to maintain a constant speed when the speed rises or drops.

The arrangement of governor balls in an inertia governor involves the governor shaft’s angular acceleration producing an inertia force that moves the balls around. A spring and a governor mechanism work together to control the balls’ displacement, which in turn controls the amount of air-fuel mixture supplied.

Inertia governors are often chosen over centrifugal governors due to their desired balance of rotating elements. They offer tight and exact control over speed, fast reaction time to load or speed fluctuations, efficient management of sporadic and unexpected loads, consistent and dependable speed control, and do not require outside power sources.

However, inertial governors have disadvantages such as increased costs due to complex design and construction, frequent maintenance and modification, not recommended for high-speed applications, susceptibility to external influences like shock and vibration, and restricted control range compared to electronic controls.

engine governor diagram

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