What are the advantages of dual carburetor over single barrel carburetor?

The single-barrel carburettor has only one barrel, whereas a dual carburettor has two-barrel. Engine with higher displacement requirement is large-bore to provide adequate airflow makes throttle response too fast so some automobile manufacturer used two-barrel used in carburettor in this type of engine. Let us have a deep insight into the advantages of used dual carburettor over single barrel carburettor?


Advantages of dual carburettor : 

  • The duel carburettor supplies a charge of a mixture to the cylinders which are uniform in quality. 
  • Volumetric the efficiency of the dual carburettor is higher than a single barrel carburettor. 
  • The charge of the air-fuel mixture is distributed to each cylinder in a better manner. 
  • The dual a carburettor is compact in its design. 

Why are double barrel used in the carburettor?

The fight is only and only efficiency and performance when the question comes to the carburettor. Many older carburettors are single barrel which is fine for low HP applications. The problem is that higher displacement engine as we have seen in the first paragraph. To getting a fairly constant fuel-air ratio across the engine double-barrel carburettor can be optimised. At low RPM and low power demand, only one provides a fuel-air mix to the engine. When more RPM or power is required, the second barrel comes into play and allowing the different fuel-air ratio to be used and provide a better fuel-air mix to the engine. 

Carburetor size

The size of a carburettor is generally given in terms of the diameter of the venturi tube in mm and the jet size in hundredths of a millimetre. 

The calibrated jets have a stamped number which gives the flow in ml/min under ahead of 500 mm of pure benzol. 

Jet size is usually one-sixteenth of venturi size. 

For a venturi of 30 to 35 mm size, the pressure difference (p1-p2) is about 50 mm of Hg. The velocity at the throat is about 90 - 100 m/s and the coefficient of discharge for venturi Cda is usually 0.85. 

Normally the size of carburettor 1 or 2, 3 or 4 barrel, a little bit of confuse about the size so there is a formula for choosing a proper size in cfm for your engine.

Formula :

First step: CC full form is cubic displacement divided by 2.

Second step: Maximum RPM is divided by 1728.

Third step: Multiple above two step figure. 

Fourth step: Multiply third step answer with volumetric efficiency for that engine depending on what you have done with your heads and exhaust. 

Fifth step: Final Answer in cfm.

Factor affecting carburetion

The process of carburetion is influenced by various factors following below :
  • The engine Speed 
  • The vaporization characteristics of the fuel 
  • The temperature of the incoming air 
  • The design of the carburettor 
Since modern engines are of high-speed type, the time available for mixture formation is very limited. 

For example, An engine running at 2500 RPM has only about 10 milliseconds for mixture induction during the intake stroke. When the speed become 5000 RPM the time available is only 5 millisecond.
therefore in order to have high-quality carburetion, the velocity of the airstream at the point where the fuel is injected has to be increased. This is achieved by introducing a venturi section in the path of the air. The fuel is discharged from the main metering jet at the minimum cross-section of venturi. 

Other factors which ensure high-quality carburetion within a short period are the pressure of highly volatile hydrocarbons in the fuel. Therefore, suitable evaporation characteristics of the fuel indicated by its distillation curve are necessary for efficient carburetion, especially at high engine speeds. 

Also, another parameter like the temperature and pressure of the surrounding area has a large influence on efficient carburetion. Higher atmospheric air temperature increases the vaporization of fuel and produces a more homogeneous mixture. An increase in atmospheric temperature leads to a decrease in power output of the engine when the air-fuel ratio is constant due to reduces mass flow into the cylinder or in other words reduced volumetric efficiency. 

The design of carburetor, the intake system and the combustion chamber have influence on uniform distribution of mixture to the various cylinders of the engine. proper design of carburetor elements alone ensures supply of desired composition of the mixture under different operating condition of the engine.

Advantages of multiple venturi carburetion system

When one or more secondary venturi enclosed inside the main venturi of a carburettor is called multiple venturi carburettor and this carburetion system is called a multiple venturi carburetion systems. Benefits of using this and results of multiple venturi carburetion system are listed below. 

Advantages of multiple venturi carburetion system : 

  • Reducing condensation of the fuel :
The main jet discharges the fuel into the primary venturi in an upward direction against the downward airstream in a multiple venturi system. The airflow atomizes the fuel. The primary venturi keeps the fuel thus atomized in the primary venturi centrally located in the air stream.

In addition, a blanket of air surrounding the primary venturi and passing into the secondary venturi keeps the atomized fuel in the air stream centrally located. Through this process, the carburettor walls are protected for a certain distance from coming into contact with fuel, thus reducing condensation.
  • High-speed system : 
The throttle valve is sufficiently opened when the speed is to be increased from low to high. The air flows faster through the primary venturi when the throttle valve is wider open. In the portion of the jet orifice, this airflow produces a vacuum. Because of this increase in a vacuum, the main jet will discharge additional fuel. The high-speed system maintains an almost constant air-fuel ratio.
  • Due to high depression created at the region of fuel nozzle better automatization, and better control of fuel.
  • The excellent air-fuel mixture is achieved without any reduction in volumetric efficiency.  
  • The excellent low-speed full throttle operation is provided.

Chemical structure of petroleum

Petroleum, as obtained from the oil wells, is predominantly a mixture of many hydrocarbons with differing molecules structure. It also contains a small amount of sulphur, oxygen, nitrogen and impurities such as water and sand. 

The carbon-hydrogen atoms may be linked in different ways in a hydrocarbon molecule and this linking influences the chemical and physical property of different hydrocarbon groups. Most petroleum fuels tend to exhibit the characteristics of that type of hydrocarbon which forms a major constituent of the fuel. 

The carbon and hydrogen combine in different proportions and molecular structure to form a variety of hydrocarbons. The carbon to hydrogen ratio which is one of the important parameters and their nature of bonding determine the energy characteristics of the hydrocarbon fuels. Depending upon the number of carbon and hydrogen atoms the petroleum product is classified into different groups. 

The differences in physical and chemical properties between different types of hydrocarbon depend on the chemical composition and affect mainly the combustion process and hence, the proportion of fuel and air required in the engine. The basic families of hydrocarbons, their general formula and their molecular arrangement are shown below :

1. Paraffin :
  • General formula: CnH2n+2
  • Molecular structure: Chain 
  • Saturated / Unsaturated : Saturated 
  • Stability: Stable 
2. Olefin :
  • General formula: CnH2n
  • Molecular structure: Chain 
  • Saturated / Unsaturated : Unsaturated 
  • Stability: Unstable 
3. Naphthene :
  • General formula: CnH2n
  • Molecular structure: Ring 
  • Saturated /Unsaturated: Highly saturated 
  • Stability: Most stable 
4. Aromatic : 
  • General formula: CnH2n-6
  • Molecular structure: Ring 
  • Saturated / Unsaturated : Unsaturated 
  • Stability: Unstable 

Classification of fuels

Based on the type of fuel used by engines are classified as :
  • Engine using volatile liquid fuels for example - gasoline, alcohol, kerosene, benzene etc. The fuel generally mixed with air to form a homogeneous charge in a carburettor outside the cylinder and drawn into the cylinder in its suction stroke. By an externally applied spark, the charge is ignited near the end of the compression stroke. These engines are called spark-ignition engines. 
  • Engine using gaseous fuels like CNG full form Compressed Natural Gas, LPG full form Liquefied Petroleum Gas, blast furnace gas and biogas. Gaseous fuels are comparatively better compared to liquid fuels because of reduced ignition delay. The gas is mixed with air and the mixture is introduced into the cylinder during the suction process. Working of this type of engine is similar to that of the engines using liquid fuels called SI gas engine.
  • Engine using solid fuels like charcoal, powdered coal etc. Solid fuels are generally converted into gaseous fuels outside the engine in a separate gas producer and the engine works as a gas engine. 
  • Engine using viscous liquid fuels like heavy and light diesel oils. The fuel is generally introduced into the cylinder in the form of minute droplets by a fuel injection system near the end of the compression process. Combustion takes place because of the fuels coming into contact with the high temperature compressed air in the cylinder. Therefore, these engines are called compression-ignition engines. 
  • Engines using two fuels. A gaseous fuel or a highly volatile liquid fuel is supplied along with air during the suction stroke or during the initial part of compression through a gas valve in the cylinder head and the other fuel is injected into the combustion space near the end of the compression stroke. These are called dual-fuel engines.  

Definition of heat engine

What is a heat engine?

In thermodynamics and engineering a device for producing motive power from heat. 

A heat engine is a system that converts thermal and chemical energy into mechanical energy which can be used to do mechanical work.  


Heat engine can be classified into two categories :

  1. Internal combustion engine 
  2. External combustion engine

Engines are also classified into two types :

  1. Rotary engines 
  2. Reciprocating engines 

Definition of Engine

What is the engine?

A machine that converts any of various form of energy into mechanical force and motion. 

A mechanism which can serve as an energy source. 

Normally, most the engines convert thermal energy into mechanical work and therefore they are called Heat Engine. 

The engine can be broadly classified into two categories :

  1. Internal combustion engine
  2. External combustion engine 

Difference between spontaneous and stimulated emission

What is called spontaneous emission?

Spontaneous emission is electron drops from an excited state to a lower state. 

Example - emitting a photon.

What is called stimulated emission?

Stimulated emission is photon of the same frequency interacts with an electron in an excited state which drops to lower state. The emitted photon is coherent with the incoming photon.

Example - Laser 

Let us have deep insight into the difference between these two emissions.

Differences :

  • Where quantum system undergoes a change and jumps to a lower energy state, emitting quanta of energy is called the spontaneous emission Whereas stimulated emission is the process where an external photon of a certain frequency, reacts with the excited electron in an atom and this results in dropping to lower energy state.
  • Spontaneous emission found in LEDs, Fluorescent tubes and stimulated emission found in laser it is the key process for the formation of a laser beam. 
  • There is no population inversion of electrons in LEDs in spontaneous emission whereas population inversion is achieved by various pumping technique in stimulated emission. 
  • In spontaneous emission, external stimuli are not required and stimulated emission is caused by external stimuli. 
  • Spontaneous emission depends only on the upper level of the electron whereas stimulated emission depends upon the electron being in the upper level but the electron must be started at the upper level. 
  • Only one energy wave is released during spontaneous emission while two energy waves are released during stimulated emission. 
  • Spontaneous emission is the self-emission process of radioactive materials without any influence of radiation whereas a single particle or group of particles initiated emission in radioactive material is called stimulated emission.

Stimulated emission

The concept of stimulated emission was first put forward by Albert Einstein in 1917.

Let us consider two energy levels E1 and E2 in a material. Let us assume that the atom is initially at energy level E2. Also, consider that an electromagnetic wave of frequency v is incident on a given material. This wave has the same frequency as that of the specific material. Therefore, there is a high degree of probability that this wave will force the atom to undergo a change from energy level E2 to energy level E1. In this case, the energy difference E2 - E1 is received in the form of an electromagnetic wave which adds to the incident wave. Here, it is to be noted that the atom is already in the excited state E2. Before it could come to the ground state, due to the spontaneous emission process, if it is irradiated with a photon, whose energy is exactly equal to E2 - E1. The incident photon will stimulate the excited atom to emit one photon of exactly the same energy, like that of the incident photon. Thus, two photons will be emitted in this process. This phenomenon is known as Stimulated Emission. 


Stimulated emission

Note: The most remarkable feature of the stimulated emission is both the emitted photons will have the same frequency, phase direction and polarization, as that of the incident photon. So, in this process, we give input of one incident photon and obtain the two photons identical in all respects as an output. Thus, amplification of radiation takes place by the stimulated process. 

Spontaneous emission



Let us consider two energy levels E1 and E2 in a material. For convenience, E1 is taken to be the ground level. E2 being greater than E1. ( E2 > E1 ) The two levels of energy under consideration can be any two of the unlimited numbers of levels of energy that can be possessed by any material. 

E1 = Energy level 1 ( Ground state )
E2 = Energy level 2 ( Excite state ) 
h = Plank's constant
v = Frequency of radiated energy 

Spontaneous emission

When the particle or atom of the material is excited, it can remain in the excited state for a limited time known as lifetime. The lifetime of the excited hydrogen atoms is of the order of 10-8 sec. Usually, the number of excited particles in a system is smaller than the non-excited particles. The time during which a particle can exist in the ground state is unlimited. The particle at the excitement level is more unstable as compared to that at the ground level. Naturally, there is a tendency for the particle to come back to ground level. When it comes back to ground level, the particle releases some amount of energy. When this energy is released in the form of electromagnetic waves, we call it spontaneous emission of energy. Frequency of the radiated wave is given by :

v = ( E2 - E1 / h ) 
OR 
hv = ( E2 - E1

Note: Radiative emission is just one of the two possible ways for the atom to decay. The decay can also occur in a non-radiative manner. In the non-radiative transition, the difference in energy levels E2 and E1 can be experienced in regions other than electromagnetic. 

Types of mechanical vibration

There are mainly three basic types of vibration according to the axis of body move : 

  1. Longitudinal vibration 
  2. Transverse vibration 
  3. Torsional vibration 
Now we can check it out in details below :

  • Longitudinal vibration :
If the shaft is elongated and shortened so that the same moves up and down resulting in tensile and compressive stresses in the shaft, the vibrations are said to be longitudinal. The different particles of the body move parallel to the axis of the body. 

  • Transverse vibration :
When the shaft is bent alternately and tensile and compressive stresses due to bending result, the vibrations are said to be transverse. The particles of the body move approximately perpendicular to its axis. 

  • Torsional vibration :
When the shaft is twisted and untwisted alternately and torsional shear stresses are induced, the vibrations are known as torsional vibrations. 

There are also some more vibrations that are following below :
  1. Free and Forced vibration 
  2. Linear and non-linear vibration 
  3. Damped and Un-damped vibration 
  4. Deterministic and Random vibration 
Now we can check it out in details below : 

  • Free vibration : 
After distributing the system, the external excitation is removed, then the system vibrates on its own. This type of vibration is known as free vibration. 

Example - Simple pendulum 

  • Forced vibration 
The vibration which is under the influence of external force is called forced vibration. 

Example - Machine tools, electric bells

  • Linear vibration : 
In a system, if mass, spring and damper behave in a linear manner, the vibrations caused are known as linear in nature. 

They are governed by linear differential equations. 
They follows the law of superposition. 

  • Non-linear vibration : 
If any of the basic components of a vibratory system behaves non-linearly that type of vibration is called non-linear in nature. 

Linear vibration becomes non-linear for very large amplitude of vibrations. 
They does not follows the law of superposition. 

  • Damped and Un-damped vibration : 
If the vibratory system has a damper and the motion of the system will be opposed by damper also the energy of the system will be dissipated in friction is called damped vibration. 

On the other hand the system having no damper is known as un-damped vibration. 

  • Deterministic and Random vibration :
In the vibratory system, the amount of external excitation is known in magnitude, it causes deterministic vibration is called deterministic vibration.

The non-deterministic vibration are known as random vibration. 


Introduction to mechanical vibration

A body is said to vibrate if it has a to and fro motion. A pendulum swinging on either side of a mean position does so under the action of gravity. When the pendulum swings through the mid position, its centre of mass is at the lowest point and it possesses only kinetic energy. At each extremity of its swing, it has only potential energy. In the absence of any friction, the motion continues indefinitely. It can be shown that if the swings on either side of the mean position are very small, it approximates to simple harmonic motion. 

Usually, vibrations are due to elastic forces. Work is done on the elastic constraints of the forces on the body when a body is displaced from its equilibrium position and is stored as strain energy. Now, if the body is released, the internal forces cause the body to move towards its equilibrium position. If the motion is frictionless, the strain energy stored in the body is converted into kinetic energy during the period the body reaches the equilibrium position at which it has maximum kinetic energy. The body passes through the mean position, the kinetic energy is utilized to overcome the elastic forces and is stored in the form of strain energy. 

The vibration is mainly three types :

  1. Longitudinal vibrations
  2. Transverse vibrations
  3. Torsional vibrations 
Terms related to vibration :
  1. Free vibration 
  2. Damped vibration 
  3. Forced vibration 
  4. Period
  5. Cycle
  6. Frequency 
  7. Resonance 
All the terms are used in vibrations are explain below :

Free vibration is also called natural vibration. Elastic vibration in which there are no friction and external forces after the initial release of the body is known as free vibration.

Damped vibrations are when the energy of a vibrating system is gradually dissipated by friction and other resistances is called damping. The vibrations gradually cease and the system rests in its equilibrium position.

Forced vibration is when a repeated force continuously acts on a system. The vibration is said to be forced. The frequency of the vibrations is that of the applied force and is independent of their own natural frequency of vibrations. 

The period is the time taken by a motion to repeat itself and is measured in seconds. 

The cycle is the motion completed during one time period. 

Frequency is the number of cycles of motion completed in one second. It is expressed in hertz ( Hz ) and is equal to one cycle per second. 

Resonance is the frequency of the external forces is the same as that of the natural frequency of the system. 
A state of resonance is said to have been reached. 

It results in large amplitudes of vibrations and this may be dangerous. 

Watt governor application


  • Watt governor used to maintain the engine's speed of the truck.
  • It also used in ship and train.
  • It used in a steam turbine, the internal combustion engine and variously fueled turbine. 
  • It also used in AC generators to maintain the electricity supply with the load increase on it. 
  • It used in automobiles to restrict engine RPM and total speed. 
  • It also protects the engine from excessive rotational speed.
  • We also used in that system where working fluid and speed of the system are main issues. 

Watt governor

Watt governor is the simplest form of a centrifugal governor. It is also called simple conical pendulum governor. It is basically a conical pendulum with a link attached to a sleeve of negligible mass. This governor is used by James Watt in his steam engine and it also has many applications

Working of Watt governor :


The upper sides of arms are pivoted with the governor balls so the governor balls can move upward and downward as they revolve with a vertical spindle. Bevel gears drive the engine. A bevel gear is driven by the spindle. The lower arms are connected to the sleeves and are keyed to the spindle in such a way that revolves with the spindle. At that time, it can slide up and down according to the spindle speed. Two stoppers are provided at the bottom and top of the spindle to limit the movement of the sleeve.


If the load on the engine decreases, the speed of the engine and then the angular velocity of the governor spindle increase. The centrifugal force on ball increase that tends balls move outward and sleeve move upward thus sleeve actuates a mechanism that operates the throttle valve at the end of bell crank lever to decrease the fuel supply. Thus the power output is reduced.


If the speed of the engine decreases as the load on the engine increase, the centrifugal force decreases. So that the inward movement fly balls and downward movement of the sleeve cause a wide opening of the throttle valve. Engine speed increase with increasing the fuel supply.


Types of Watt governor :

The Watt governor classified based on the position of upper arms. The arms can be connected by the way we describe below :

  1. Pivot is on the axis of the spindle 
  2. Pivot is offset from spindle
  3. Pivot is offset, and arms cross the axis.
Based on this Watt governor are classified into three types :
  1. Simply pinned type governor 
  2. Open arm type governor 
  3. Crossed arm type governor 
Simply pinned type governor: The upper arms are joined to a point O on the axis of the spindle, where both arms intersect the spindle axis.

Open arm type governor:
 The upper arm of Watt governor is hinged on a collar attached to the spindle or joined by a horizontal link as shown in fig below i
nstead of connecting directly to the spindle. The arms, when produced, meets the axis of the spindle at O. 

Crossed arm type governor:
 The upper arms o governor in hinged on a collar on the axis of the spindle or arms are joined through a fixed horizontal link as shown in fig below. The arms intersect the axis at a point O.



Watt governor


Limitations of Watt governor :
  • Its use is limited up to vertical position applications. 
  • It is used in very slow speed engine because, at higher speed, the sensitivity of governor will decrease. 
Height Calculations :

The vertical distance from the plane of rotation of the balls to the point of intersection of the upper arms along the axis of the spindle is called the height of the governor. 

The height of the governor decreases with an increase in speed and increases with a decrease in speed. 

Let, 
m = mass of each ball
h = height of governor
w = weight of each ball ( w = mg )
ω = angular velocity of the balls, arms and the sleeve
T = Tension in the arm
r = radial distance of ball-centre from spindle- axis 

For the finding h the height of governor the equilibrium of the mass provides 

Tcosθ = mg and Tsinθ = mrω2
Tanθ = mrω2 / mg = rω2 / g
r / h = rω2 / g
h = g / ω2 = g / ( 2πN / 60 ) = ( 60 / 2π )2 * 9.81 / N2
h = 859 / N2 m
h = 859000 / N2 mm

Thus, the height of a Watt governor is inversely proportional to the square of the speed. 

Hunting of governor

Definition of hunting of governor :

You know that the function of the governor is to keep the speed constant so hunting of a governor is the condition in which the speed of the engine that can fluctuate continuously above and below the mean speed and which are controlled by the governor.

In other words, hunting is said to occur in a governor when it is not able to find a stable position for a change in load at a new value of speed and oscillates around it due to the tendency of balls and sleeve to restore original speed and inertia effect leading to an overshoot of the desired position.

Process of hunting :

Sensitiveness of a governor and hunting of a governor both are a desirable quality. If a governor is too sensitive, it may fluctuate continuously, because when the load on the engine falls, the sleeve rises rapidly to a maximum position. This shuts off the fuel supply to the extent to affect a sudden fall in the speed. As the speed falls to below the mean value, the sleeve again moves rapidly and falls to a minimum position to increase the fuel supply. The speed subsequently rises and becomes more than the average with the result that the sleeve again rises to reduce the fuel supply. This process is continuing and it is known as hunting of governor. 

Hunting is directly proportional to sensitiveness. If more sensitive the governor, more is the hunting.

Sensitiveness of governor

Definition of sensitiveness : 

The ratio of the difference between the maximum and minimum equilibrium speed to the mean equilibrium speed is called sensitiveness of governor.

A governor is said to be sensitive when it readily responds to a small change of speed. The movement of the sleeve for a fractional change of speed is the measure of sensitivity. 

Explanation of sensitiveness :

As a governor is used to limit the change of speed of the engine between minimum to full-load conditions, the sensitiveness of a governor is also defined as the ratio of the difference between the maximum and the minimum speeds to the mean equilibrium speed. 

Sensitiveness = Range of speed / Mean speed 

                       = N2 - N1 / N 
                       
                       = 2 ( N2 - N1 ) / N1 + N2 

Where, 

N = Mean speed
N1 = Minimum speed corresponding to full load condition 
N2 = Maximum speed corresponding to no-load condition 


Types of governor


Governor is known as speed manager OR speed controller. 

They are used in automobile engine to measure and regulate the speed of an engine. It uses gears and flyweights inside the crankcase to detect changes in the load and adjusts the throttle accordingly.

Governor can broadly classify in two types :


  1. Centrifugal governor 
  2. Inertia governor 
Now let we know brief details about these two types of the governor.

  • Centrifugal governor :
This is the most common types of governor. Its action depends on the change in speed. It has a pair of masses, known as governor balls, which rotate with a spindle. The spindle is driven by an engine through bevel gears. 

The action of this governor depends upon the centrifugal effects produced by governor ball. With the increases in speed, the balls tend to rotate at a greater radius from the axis. This causes the sleeve to slide up on the spindle and this movement of the sleeve is communicated to the throttle through a bell crank lever. This closes the throttle valve to the required extent. When the speed decreases, the governor balls rotate at a smaller radius and the valve is opened according to the requirements. 



Centrifugal governor



Centrifugal governor again classified into two groups :

  • Pendulum type governor :
Pendulum type governor is Watt governor. 

  • Loaded type governor :
Loaded type governor is Porter governor, Proell governor, Hartnell governor, Wilson Hartnell governor, Hartung governor and Pickering governor. 

  • Inertia governor :
In this type of governor, action depends on acceleration. The position of the balls is affected by the forces set up by angular acceleration or deceleration of the given spindle in addition to centrifugal forces on the governor balls. Using suitable linkage and springs, the change in position of the balls is made to open or close the throttle valve. 

Thus, the governor balls are operated by the actual change of engine speed in the case of centrifugal governors, it is by the rate of change of speed in case of inertia governor. Therefore, the response of inertia governors is faster than that of the centrifugal governor.




Inertia governor

What is mechanical governor

What is the governor ?

In simple word, the governor controls engine speed. It uses gears and flyweights inside the crankcase to detect changes in the load and adjusts the throttle accordingly.

The function of a governor ?

To maintain the speed of an engine within specified limits whenever there is a variation of load occurs.

How it works?

The governor system is like a cruise control system in an automobile. It maintains the speed of your lawn mower or outdoor power products. 

In general, the speed of an engine varies in two ways, during each revolution and over a number of revolutions. For the first case, it is due to variation in the output torque of the engine during a cycle and can be regulated by mounting a suitable flywheel on the shaft. While in the second case, it is due to variation of the load upon the engine and requires a governor to maintain the speed.

If the load on the shaft increases, the speed of the engine decreases unless the supply of fuel is increased by opening the throttle valve. 

If the load on the shaft decreases, the speed of the engine increases unless the fuel supply is decreased by closing the valve sufficiently slow the engine to its original speed. 

Thus, the throttle valve operated by the governor through a mechanism for the purpose. 

Use of governor?

A governor used to measure and regulate the speed of a machine, such as an engine. It is also called speed limiter or controller. 

There are two types of governor used in any automobile application. One is centrifugal governor and another is inertia governor. 

What is Unbalance

In simple word, we can say that make someone unsteady so that they fall is called unbalance. 

In theoretical language, the condition which exists in a rotor when vibratory force or motion is imparted to its bearings as a result of centrifugal forces is called unbalance or the uneven distribution of mass about rotor's rotating line.  

Difference between static and dynamic balancing

Balancing of forces is most important in any machinery industries. Unbalance of forces is produced by the inertia forces connected with the moving mass in rotary or reciprocating machinery.

Balancing of a rotating body is done to counter the extra forces in the direction other than the rotation axis helps in avoiding the vibrations in a body.

There are two types of balancing static and dynamic balancing and also have some difference between both types of balancing. Let us have deep insight into the difference between static balancing and dynamic balancing.

Main difference :  

Only forces are balanced in static balancing whereas, in dynamic balancing, both the forces and the couples are balanced.

Difference :

  • Static balancing is performed with the object which is balanced at rest and dynamic balancing is performed with the object being balanced in motion.
  • The static balance will be produced if the sum of weights about the axis of rotation is zero and dynamic balance will be produced there doesn't exist any resultant centrifugal force as well as a resultant couple.
  • Static balancing is done where the centre of gravity is on the axis of rotation of the body while dynamic balancing is done where the body is either rotating about the axis due to an external force or by the change in the centre of gravity of the body.
If we consider balancing whether it is static or dynamic but balancing can help to extend the service life, quality and accuracy of your machine while unbalanced parts can lead to breaking down to your machine.

Dynamic balancing

What is dynamic balancing?

A system is in dynamic balance when there does not exist any resultant centrifugal force and also a resultant couple. 

For example Several rotating masses 


When several masses rotate in different planes, the centrifugal forces in addition to being out of balance also from the couple. 

Dynamic balancing

As shown in the figure above the product of mr an mrl usually have been referred to as force and couple respectively as it is more convenient to draw force and couple polygons with these quantities. 

If m1 and m2 are two masses revolving diametrically opposite to each other in different planes such that m1r1 = m2r2.

The centrifugal forces are balanced, but an unbalanced couple of magnitude m1r1l1 = m2r2l2 is introduced. 

The couple acts in a plane that contains the axis of rotation and the two masses. Thus, the couple is of constant magnitude but variable direction.