Types of Car Transmission (Part 3)

( Continued from previous articles )

Types of Automatic Car Transmission by Brand

In the previous article we have discussed how the basics of automatic gearbox transmission system work. Next time I will mention the technologies of automatic transmission on cars that have been developed by various brands in the world. Various developments have been done by these brands. So it could be different with that I have explained before.

  • Honda Automatic Transmission

    The car manufacturer Honda has developed automatic transmission technology since 1960s. While other Japanese car manufacturers are busy pursuing contracts with patent holders over Borg Warner’s automatic transmission, Honda actually took the initiative to develop its own automatic transmission system. The reason is because the automatic transmission system at that time is too large and less efficient to be applied to Honda cars that are designed smaller than the cars of the United States manufacturer. As a result they managed to develop a typical automatic transmission system by Honda, and given the title Hondamatic .

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    Hondamatic 4-Acceleration

    Unlike the automatic gear transmission systems in general that use planetary gears, Hondamatic uses a gear system with a parallel shaft axis as in manual transmission systems. Each gear ratio is controlled by a coupling system that is separate from one another. And the clutch is controlled by hydraulic system.

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    Modern Hondamatic

    Currently, Honda has developed Hondamatic transmission system that will used for ATV vehicles ( All Terrain Vehicles ) Honda brand. This transmission system uses the principle of hydromechanical continuously variable transmission, which uses a hydraulic pump Swash-Plate and an Adjustable Swash-Plate hydraulic motor.

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    Honda ATV with Hondamatic Transmission

    Swash-Plate Pump is a pump with multiple pistons, arranged parallel to the axis of the drive shaft. Hydraulic swash-plate on this system becomes the independent variable that determines the system transmission ratio. The beveled hydraulic side of the swash-plate can vary the angle of its inclination according to the generated hydraulic pressure as well as the road faced. This hydraulic motor is connected to the wheel drive shaft, so the change of slope angle swash-plate causes a change in the speed of the rotation of the shaft.

    The development of the Hondamatic transmission system for cars continues to this day. Since the introduction of the hondamatic system with the H2 code to the world in 1973 on Civic, Accord, and Prelude cars, the hondamatic system for cars continues to be developed. The latest hondamatic development for Honda cars coded H6 was introduced in 2010 using Continuously Variable Transmission technology with 6-speed forward and 1-reverse, and applied to the 2013 Honda Accord.
    ( Resources )

  • Aisin Automatic Transmission

    Aisin is one of the automotive manufacturers that focus on producing car transmission systems. Various famous car brands use a transmission system manufactured by Aisin. Well-known brands such as Toyota, Mazda, Jeep, Volvo, Peugeot, until Alfa Romeo consistently use Aisin transmission. Market data in 2005, Aisin succeeded in mastering the market share of the car transmission system by 16.4% by producing 4.9 million units of transmission system and has exceeded General Motors.

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    Alfa Romeo Brera Using Aisin Automatic Transmission AWTF-80 SC

    Aisin first produced automatic transmission in 1969 after working with other manufacturers of transmission systems BorgWarner. The automatic transmission system produced by Aisin uses the basic principle of planetary gearset as I have described in previous article. As one example of the latest automatic transmission system developed by Aisin is AWTF-80 SC type. This type of transmission is used in luxury cars like Alfa Romeo (159, Brera, Spider), Cadillac BLS, Citroën (C6, DS5), Fiat Croma, Ford (Fusion, Mondeo), Land Rover (FreeLander 2, Range Rover Evoque) , Mazda (CX-7, CX-9), Opel (Zafira, Insignia), Peugeot (508, 607), Renault (Espace, Vel Satis), and Volvo (V60, S80, CX70, CX90).

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    Aisin AWTF-80 SC Transmission System

    Aisin AWTF-80 SC transmission is designed for transversal type car engines that can generate torque of 440 N·m (324.5 ft·lbf). The transversal engine is a machine with a crankshaft position perpendicular to the main axis of the car, this position is very common in cars with front-wheel drive.

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    Aisin AWTF-80 SC Specification

    Aisin AWTF-80 SC design team makes this transmission has 6 levels of acceleration that has the same transmission block size as the manual system. This transmission combines a 5th planetary gear transmission system with a Ravigneaux gear system that features two different sized sun gears. Switching between gear ratios is governed by the clutch-to-clutch clutch system. The clutch-to-clutch clutch system eliminates the function of the steel bands used to lock the gears in stationary positions, because of the use of a second frictional clutch to lock the first friction clutch that is locking the gear in a certain position.

    This clutch-to-clutch system setup is performed by a sophisticated Transmission Control Module (TCM) system. In Aisin AWTF-80 SC transmission, TCM is located within the transmission system block, so no complicated cabling system is required outside the transmission system. This transmission system requires 8 liters of hydraulic oil for its operation.
    ( Resources )

  • General Motors Automatic Transimission

    General Motors (GM) became the first automaker to use the automatic gearbox transmission system in the world. The first car produced by GM with automatic transmission was Oldsmobiles in 1939 and marketed a year later. Since then the automatic transmission system developed by GM continues to grow. And here are the automatic transmission technologies:

    • Hydramatic (1940-1970). Being the first automated transmission system developed by GM. This transmission uses three sets of planetary gears, two fluid-coupling (not torque converter), as well as two hydraulic pumps. Hydramatic has 4-speed forward and 1-speed back.

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      Hydramatic Transmission

      Further development of hydramatic systems is used in various brands of GM cars, including Flightpitch, Dynaflow, and Dual Path Turbine Drive for Buick, Powerglide for Chevrolet, Turboglide for Chevrolet V8, and Roto-Hydramatic for Oldsmobiles.

    • Turbo-Hydramatic (1970-1990s). Turbo-Hydramatic (TH) is a development of the Hydramatic system. GM’s change is to replace the fluid-coupling with torque-converter.

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      Turbo-Hydramatic Transmission

      Turbo-Hydramatic transmission is not only used by GM cars only, but also other famous car brands such as Ferrari 400, Jaguar XJ-12, Rolls-Royce Silver Shadow, and Nissan Prince Royal.

    • Electronic-Hydramatic (1990-present). GM’s last automatic transmission system is Electronic-Hydramatic (EH). One of the EH transmissions is the 4L30-E type produced by the GM’s transmission division in Strasbourg, France. One of the cars that use this type of transmission is the BMW 325i in 1992-1995.

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      Electronic-Hydramatic Transmission Type 4L30-E

      The electronic control system of the 4L30-E type has advanced facilities such as the system’s adaptive capability to the driver’s driving style, hydraulic temperature and hydraulic oil compensation, over-speed machine protection, extreme high temperature protection, and more.

    ( Source 1, 2)


  1. Ravigneaux Planetary Transmission
  2. Description Automatic Gearbox
  3. Basic Mechanical Power Transmission
  4. Mechanical Power Transmission Fundamentals

Types of Car Transmission (Part 2)

( Continued from previous articles )

Automatic Gearbox Transmission

In the previous article we have discussed about the gearbox transmission system (gearbox) manual, where the operation of the removal of the teeth ratio is done manually by the rider. The next gearbox transmission system that we will discuss is the automatic gearbox transmission system. Switching between gear ratios in this gearbox system occurs automatically without the initiation process of the rider. The driver simply chooses the D ( Drive ) transmission to go forward, R ( Reverse ) to back off, P ( Parking ) for parking position, and N for neutral position. Once the rider chooses a D transmission, the transmission system will automatically shift the transmission to various ratios according to the speed of the vehicle and the field encountered.

Currently the development of automation technology gearbox transmission system is very advanced rapidly. Almost all leading car brand manufacturers are developing automated transmission system technology with different technologies and have become its own trademark.

Automatic Hydraulic Transmission System

Before I mention and explain about the various technologies of automatic transmission systems that have been developed by various car brands, I will explain one basic technology of automatic transmission gearbox system that is automatic hydraulic transmission system. Hydraulic transmission system is the development of hydraulic system in the form of fluid coupling which is combined with the use of gear transmission system in it. The main components of the automatic hydraulic transmission system are as follows:

  • Torque Converter. Torque converter is the development of hydraulic coupling (fluid coupling) which serves to connect between axis drive from the engine with automatic transmission gearbox system shaft. Converter torque replaces the friction clutch function in the manual transmission system. It is intended that the engine can always work even when the vehicle is in rest.

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    Components Torque Converter

    In contrast to fluid coupling, the torque characteristics of the converter is to increase the torque of rotation when the rotation speed of the shaft shaft is different from the speed of the transmission shaft spin. This is due to the presence of a single component in the form of a stator blade located halfway between the pump and the hydraulic turbine.

  • Hydraulic Pumps. An automatic hydraulic transmission system definitely requires a gear pump type hydraulic pump mounted on a central axle between the converter torque and the gear system. This pump serves to generate pressure on hydraulic oil which is then used for other system components.

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    Gear Pump In Automatic Transmission

    Sources of propulsion and pressure generation of this pump is the torque converter, so the faster the engine speed the faster the flow of flowing hydraulic oil flow. While the pressure is raised, also depends on the load conditions (road terrain) facing the vehicle. If the field is heavy, the hydraulic oil pressure will also be high. This concept will be used later in the selection of transmission gear ratios automatically.

  • Planetary Gear System . The most important component of an automatic transmission system is a series of planetary gear systems. This gearbox system consists of three parts of the gear of the sun gear, planetary gear, and the outer gear. Only by adjusting the rotation distribution configuration on the gearbox gear system, we will get 4 kinds of transmission system that is 3 forward transmission (direct rotation) and 1 reverse transmission (reverse rotation).

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    Planet Gear

    Three of the planet’s gear components, each of which can be a driving gear, a moving gear, or a silent gear. Determination of the gear configuration will result in varying ratio ratios. Notice if we determine the number of teeth on the outer gear is 72, and the sun gear is 30, then we will get some kind of gearbox ratio by adjusting the gear configuration. Notice the following table.

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    Planetary Gear Ratio

    In addition, if two of the three gears are in the lock-stationer position, a 1: 1 gear ratio is obtained. So overall there are 4 different gear ratios with only one planetary gear system, which is 3.4: 1 (forward), 1: 1 (advanced), 0.71: 1 (forward overdrive ), and -2.4: 1 (backwards).

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    Mechanism of Planetary Gear

  • Hydraulic Control System. The automatic transmission system requires an automatic control system to adjust gear shifting on planetary gear. This control system serves to set the locking and unlocking planetary gears against driven shafts or driven shafts. Each gear in the planetary gear system should be either coupling or uncoupling from the drive shaft or the driven shaft .

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    Hydraulic Control System In Automatic Transmission Mitsubishi Pajero th. 2001

    An automatic transmission hydraulic control system has components such as clutch clutches, steel bands, hydraulic pistons, spring-loaded valve, Machine load sensors, and shift valve. Here are the functions of each of these components:

    • The frictional clutch becomes the link between the drive shaft and the shaft driven with planetary gear gears. This friction coupling is designed in a complex way so that each gear can be connected to the shaft driven and the drive shaft.

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      Automatic Transmission Clutch

      One automatic transmission system that uses planetary gear uses 4 clutch friction to adjust the performance of its gears. One clutch friction is precipitated by a spring-loaded piston. This piston works based on hydraulic oil pressure, if the pressure is sufficient then the piston will be irradiated, and if the pressure is low then the piston will return to the starting position with the help of the spring in it.

    • The steel band serves to lock the planetary gear gear at stationary position (stationary). Like a clutch, this steel band is precipitated by a piston which also operates under the hydraulic oil pressure supplied to it. If the piston is in motion, the steel band located around the gear will lock the gear and connect it to the transmission system body so that the gear is in a stationary position.

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      Automatic Transmission Steel Band

    • Spring-loaded valve acts as a rotational speed sensor for output shaft rotation. Faster rotation of the shaft, greater valve opening so that the supply of hydraulic oil pressure to the system is greater. If the pivot turns more slowly, then the valve will be closing which is assisted with the spring in it.

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      Spring-loaded valve is located withingovernor

    • The automatic transmission system must know how heavy the machine is working, so that the transmission ratio transmission can match the load of the machine at hand. So we use the machine load sensor as one main component. This sensor can use two ways, the first way is to use a cable that is connected between the position of the gas pedal with the transmission system. If the accelerator is deeper pressed, then the pressure on the cable also increases. The second way is to use a vacuum modulator, by connecting the intake manifold with the transmission system (shift valve). The larger the machine load, then the vacuum modulator will read the condition of the system is getting vacuum.
    • Shift valve is a component in charge of adjusting hydraulic oil supply that will lead to actuator pistons in clutch and steel tape. Each transmission ratio shift requires one shift valve, for ratios 1 and 2 for example required one shift valve, as well as other switching ratios (2-3; 3- 4). Each shift valve has different working pressures, the higher the shift valve position, the higher the working pressure of the hydraulics. Thus, the transmission ratio transmission depends on the hydraulic working pressure controlled by spring-loaded valve according to the rotational speed of the wheel axle, which will then terminate the shift valve at a particular pressure point.

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      Shift Valve System

      Shift valve and the machine load sensor works opposite. The goal is that if the machine load is high, then the shift valve will not be too hasty to move to the next ratio until the working pressures corresponding to the specifications are met.

( Continued to next article )

Types of Car Transmission (Part 1)

The transmission system function is to transmit the speed, power and torque of the driving machine to an axle driven, with a certain ratio / transmission ratio. The rotary power generated by the driving machine always has an optimum torque value at a given RPM, while the load conditions faced by the machine tend to vary. We will get the optimum efficiency of the driving machine if it can always work on its optimum RPM, and to overcome the existing load variations then we use a transmission system that we can vary the transmission ratio.

But if on an existing load drive system is constant, then the transmission system used is a fixed transmission system. This means that this system transmits the engine rotation to the shaft driven with a fixed ratio. This fixed transmission system will not be discussed in this article. What we will discuss is the motor vehicle transmission system which of course we can vary the transmission ratio (read: acceleration). And here are the various transmission systems:

Manual Gearbox Transmission

As the name implies, this gearbox transmission uses a series of gears that are arranged in such a way that it can transmit engine speed at various acceleration ratios. A variety of manual gearbox designs for motorcycles and cars have been developed. There are 4-acceleration, 5-speed, 6-speed, and more. The acceleration of the manual gearbox transmission is done by the driver of the vehicle manually.

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Manual Gearbox Transmission

Manual gearbox transmission has the selected selection of selected acceleration ratio by way of “locking” the gear position on the output shaft. At the time of transfer ratio from position of gear one to another, required another component that is clutch that take off while rotation of engine to drive shaft.

Working Principles of Gearbox Transmission

Manual transmission gearbox system is still divided into several types based on the principle of work. These include:

  1. Sequential Gearbox Transmission . The displacement speed ratio of sequential transmission systems occurs sequentially. This system is adapted by motorcycles. On a 4-speed motorcycle for example, the displacement ratio should always be sequential from N-1-2-3- and 4. From position 1 can not jump to position 3, from 4 can not jump to position 2.

    Manual Transmission

    Motorcycle gear lever works with a unidirectional gear system, which converts the movement of the forward and backward push into a rotating motion. The rotary moves a selector barrel with three or four levers mounted around the barrel. The barrel levers move based on the rotating position of the barrel. This lever that drives the gear position so that the rotation is obtained out of the desired shaft.

  2. Non-Sequential Gearbox Transmission . This type of transmission allows us to move the position of the gears randomly or not in sequence. This system is commonly adopted by cars, trucks, and other vehicles. This system allows us to select the position of the second straight tooth without having to pass the position of the teeth 1.

    Non-Sequential Gearbox Transmission Animation

  3. Non-synchronized Gearbox Transmission . The design of the gearbox transmission system was first introduced by Louis-René Panhard and Emile Levassor at the end of the 19th century. They have developed a gearbox transmission system with multiple multi-ratio gears. Tooth shifting must be done when the driving speed of the driving gear is equal to the speed of the driven gear spin. This is done by way of adjusting the pressure of the acceleration pedal engine (pedal gas) to get the right RPM when shifting the tooth. If RPM is incorrect, the gear will not be engage in the desired position.Although the current motor vehicle is commonly using a synchronized transmission system, the non-synchronized is still widely used. This system is commonly used in large truck engines, motorcycle racing, and also race cars. The absence of a synchronized transmission system in racing vehicles is due to a clutch system that is more susceptible to wear than the existing gears. Another reason is that mechanically the design of non-synchronized transmission is more reliable and cheaper. In addition, inter-tooth transfer in non-synchronized systems is faster than the synchronized system, which is an important point in every motorcycle or car racing.

  5. Synchronized Gearbox Transmission. A synchronized gearbox consists of two main axes, both of which have gears that meet each other, so the driving gear always moves the gear driven. But the actuated gear can rotate freely, or locked with its axis so that the shaft rotates. The gear lock system governs which gear to be used in accordance with the shifter levers that govern it. In this system used a clutch system that can adjust the rotation of the shaft, so that when the gear shift can run smooth.

  7. Pre-Selector Gearbox Transmission . As the name implies, the driver of the vehicle with the pre-selector transmission system determines the gear ratio to be used before the gearshift process in the gearbox system occurs.

( Continued to next article )

Automatic transmission system Ebook:

  1. Ravigneaux Planetary Transmission
  2. Description Automatic Gearbox
  3. Basic Mechanical Power Transmission
  4. Mechanical Power Transmission Fundamentals

Heat Pumps Classification

Naturally, heat flows from high-temperature to lower-temperature area. Natural heat transfer can be either conduction, convection, or radiation. Whereas, to be able to move heat from low-temperature to the higher, it requires special effort so as to combat natural heat transfer. To be able to do this effort required a special tool called heat pump.

Heat pump is a tool for moving heat energy from a heat source, to a destination medium termed “heat sink.” Heat pumps are designed to absorb heat energy from cold-temperature chambers, and throw them into hotter spaces. This tool will require an external power supply so it can move energy from a heat source to a heat sink.

One of the heat pumps that are familiar to us is air conditioning (AirCond). However, AirCond is only one example of heat pump applications that are used quite often we meet. In addition to air conditioning there are several other types of known heat pumps. The classification of heat pumps is based on different working principles. Here are the following:

Mechanical Refrigerator

The mechanical refrigerator or also known as a mechanical heat pump, uses the properties of a volatile and condensable special fluid. The special fluid as we know as refrigerant, is made to perform a cycle so that it can absorb heat in cold air, and throw it in hot air. Refrigerant is compressed to make it hotter in hot air areas, and refrigerant pressure is released to absorb heat in cold air environments.

The picture above is a simple cycle of the refrigerator system. A refrigerator system is composed of four main components: compressor, condenser, expansion valve (also called check valve, or metering device), and an evaporator. The refrigerator cycle begins with the inclusion of saturated vapor refrigerant-phase to the inlet of the compressor. Through the compressor, the refrigerant compressed to increase the pressure, while also make the temperature increased.

Thermodynamically, these hot and compressed refrigerants enter its superheater phase. This condition is a good time to remove the heat contained in the refrigerant to the cooling medium such as air or water. The heat dissipation from the refrigerant can occur not only because of fan, also because the superheater refrigerant temperature is hotter than the temperature of the cooling medium. This heat dissipation process occurs in the condenser.

One of the unique properties of the refrigerant is volatile, which means it has a low boiling point, as well as its high dew point. his property makes the refrigerant easy to reach the superheater phase when compressed, and immediately turns its phase to liquid after experiencing cooling process in the condenser. Thermodynamically, the liquid phase of this refrigerant is called liquid saturation phase. Furthermore, this liquid refrigerant will pass through an expansion valve so that the pressure drops suddenly. Decreasing the pressure of the refrigerant fluid will lead to change its phase adiabatically to steam again. This pressure drop will be followed by temperature decrease  so that it reaches a cooler temperature than the air to be cooled.

The cold refrigerant fluid, then enter the evaporator. A fan will circulate the hot air so it can pass through the evaporator grille. In this component there is heat transfer from hot air to cold refrigerant. This process will make the air circulation to cool, this air is needed in the refrigerator process to cool the room. While the fluid refrigerant will become hotter so that it returns to saturated vapor. To meet the refrigerator engine cycle, the saturated vapor of this refrigerant will re-enter the compressor and continue to cycle the system.

The mechanical refrigerator cooling system became the most common and most widely used. Starting from the refrigerator, air conditioning, air conditioning in the vehicle, or even if the cycle is used upside down, it can also be used to warm the room at the winter.

Magnetic Refrigerator

Magnetic refrigerator is a cooling technology use magnetocaloric effects. The magnetocaloric effect is a magneto-thermodynamic phenomenon in which a temperature change in a particular material occurs as a result of being exposed by changes in magnetic field values. Simply put, a material will rise in temperature when it is placed in higher magnetic fields. Similarly, the temperature of the material will also decrease when the magnetic field strength is lowered. But one thing to note is that these two concepts must occur in an isolated chamber so there is no absorption or heat release, an adiabatic process is a must. So that the increase or decrease of material temperature due to the magnetic field change is happening naturally.

Similar to a mechanical refrigerator, the magnetic refrigerator process also occurs cyclically. There are four cycles in the magnetic refrigerator process: adiabatic magnetization, isomagnetic enthalpies transfer, adiabatic demagnetization, and isomagnetic entropy transfer.

  1. Adiabatic Magnetization
    A magnetocaloric material, which acts as a refrigerant, is placed in an isolated chamber. Furthermore, the chamber is subjected to a magnetic field so that the atoms refrigerant material repositioned. This condition results in magnetic entropy and the material’s heat capacity being reduced. Because the system is isolated so that there is no heat transfer (adiabatic), and the total value of the entropy is not reduced, the temperature of the refrigerant material will naturally increase.
  2. Isomagnetic Enthalpy Transfer
    The second condition, with a fixed system induced by an unchanged magnetic field (isomagnetic), the heat contained by the refrigerant is cooled by the cooling fluid. The cooling fluid can be either gas or liquid. The cooling medium commonly used in this system is helium gas. The magnitude of the fixed magnetic field remains to prevent the refrigerant atoms from being re-positioned to their original position when the heat is absorbed by the cooling fluid. After the heat of the refrigerant is fully absorbed by the cooling fluid, the coolant fluid is subsequently removed from the system.
  3. Adiabatic Demagnetization
    Furthermore, the refrigerant material is re-insulated to keep no heat coming out or entering the system (adiabatic). In such conditions, the magnetic field value is lowered so that the thermal energy of the material creates a magnetic moment to overcome the change of magnetic field. This process is what makes the refrigerant temperature down. The energy transfer (and entropy) occurs from the thermal entropy to the magnetic entropy, indicating a change in the magnetic field of the system.
  4. Isomagnetic Entropy Transfer
    The next cycle process is to keep the magnetic field of the system unchanged (isomagnetic), to keep the refrigerant material unheated. Then made thermal contact between the environment or air to be cooled, with refrigerant material that is in cold conditions. Since the refrigerant temperature is cooler than the air the environment wants to cool, there is heat transfer from the hot air to the refrigerant. This process will lower the air temperature so that there is a temperature equilibrium between the two. Next, the cycle process starts at the beginning.The magnetic refrigerator technique is well suited to produce very cold environmental temperatures. Compared with conventional mechanical refrigerators, magnetic refrigerators tend to be safer, less noisy, simpler, higher cooling efficiency, and certainly environmentally friendly because they do not use harmful refrigerant materials such as CFCs in the process of mechanical refrigerators that damage ozone.

    An example of a material that has a high magnetocaloric effect and is suitable for use as a refrigerant, is gadolinium (Gd) material and its compound mixtures. The gadolinium temperature rises as it enters a certain magnetic field, and the temperature will drop too if it leaves the magnetic field. The gadolinium compounds commonly used for refrigerants include Gd5Si2Ge2, Gd5 (SixGe1-x) 4, as well as a mixture of Gd-Bi-Sb (Gadolinium-Bismuth-Antimony) composition.

Thermo-electric Refrigerator

The thermo-electric cooling system is incorporated into a solid material heat engine using the Peltier effect (also known as thermo-electric effect) to create a heat flow between two different materials. This thermo-electric effect transfers heat from one side of the material to the other, by consuming electrical energy.

Two semiconductor materials with different electron densities are used as the main components of the thermo-electric heat engine. Two materials called the n-type and p-type are arranged in parallel, but are interconnected in series in an electrical circuit. Both of them then flanked by two material heat conductor on each side. When the voltage is applied to the free end of each semiconductor, there will be DC current flow across the system, and result in a temperature difference. One side of the plate will be cooler than the surrounding area so it will absorb the heat. The heat is absorbed for the next flow to another side plate that is hotter than the surrounding room, so that heat can be discharged to the heat sink.

The thermoelectric heat has a lower thermal efficiency than mechanical refrigerator. The thermo-electric system is only capable of achieving thermal efficiency of 10-15% only. Far enough when compared with conventional mechanical coolers that can achieve efficiencies up to 40-60%. Thermo-electric refrigerator is only capable of producing a temperature differential of 70 degrees only. Materials commonly used as a thermo-electric semiconductors include bismuth telluride, lead telluride, silicon germanium, and a mixture of bismuth-antimony.

Termo-acoustic Refrigerator

The last known model of heat pump is to use sound. Slightly odd indeed, but the sound that comes out of a speaker can be used to cool the room temperature if treated with the right way and tools. Thermo-acoustic refrigerator uses sound properties to be able to compress and stretch the air. Through this principle, the compressed air will rise in temperature, while the pressure dropped air will also fall in temperature. So if a proper system is made by using this phenomenon, an inverse Brayton cycle can be made.

The main components of thermo-acoustic refrigerators include sound sources (speakers), hot and cold heat exchangers flanking a regenerator or stack (a section composed of small parallel spaces), as well as a resonator chamber. The components are arranged in a long tube room with the speakers at one end. When the stack is placed at the correct distance inside the resonator, a temperature difference will be created on both sides of the stack. If both sides of the stack are paired with heat exchangers, then heat transfer will be created.

The inverse thermodynamic cycle of Brayton from this cooling machine is:

Adiabatic compressed gas. The air will rise in pressure at the same time the temperature along with the sound frequency resonance that occurs. The temperature in this room is now higher than the temperature of the heat exchanger metal pile.

Isobaric heat transfer. The heat will move from the compressed air to the heat exchanger plate. The process of heat transfer occurs under no pressure changes.

Adiabatic expansion. Stack will expand the air so that the pressure back down. This pressure drop will simultaneously lower the air temperature so that it is lower than the plate temperature.

Isobaric heat transfer. After the air temperature drops, heat exchanger heat will move into the air without any change of pressure, so that the air temperature will return to room temperature.

References: Wikipedia: Heat Pump, Wikipedia: Magnetic Refrigeration, Wikipedia: Thermoelectric Cooling, Wikipedia: Thermoacoustic Hot Air Engine

Positive Displacement Pumps Classification

Positive displacement pump has more variation than dynamic pump. Generally it is divided into two large groups, rotary pump and reciprocating pump. Both are still divided into various types of pumps again. And here are the pumps:

  1. Positive Displacement Rotary Pump

    This rotary type moves the working fluid through a rotary mechanism by make a vacuum effect so it can suck the working fluid from the inlet side, and move it to the outlet side. If there is air trapped inside the rotary pump, it will naturally discharge the air, thereby reducing the need to vent the air trapped inside the pump manually.

    Here are all kinds of rotary pumps:

    • Internal Gear Pump

    This pump uses two gears as a working fluid driver inside the pump casing. One gear drives and the other becomes driven. The driving gear is inside the driven gear. For more details please see the following picture.


    Internal Gear Pump

    And here is the process whereby the working fluid is pumped by this internal gear pump.


    Internal Gear Pump Working Principle

    The working fluid enters through the pump inlet toward the outer gear rotated by the inner gear. The fluid moves toward the outlet side as a result of the drive from the outer gear. Furthermore the inner gear goes into the sidelines of the outer gear to push the working fluid to exit through the outlet side of the pump.

    • External Gear Pump

    Same with the internal gear pump, this external gear pump –or typically called gear pump–  also uses two gears as its main component. What distinguishes is that both gears are in parallel positions, and the driving gear is not inside the driven gear.


    Gear Pump
    • Screw Pump

    Screw pump was first developed by Archimedes. This why a screw pump also called Archimedes Screw Pump. Single screw rotor was used to move water from the river at lower point to the rice fields for irrigation purposes.


    Screw Pump

    The screw pump design has evolved into several types such as twin-rotor, triple-rotor, and 5-rotor. The differences is in the number of the screw. Here is a screw pump video with twin-rotor.

    The working principle of screw pump with multi-rotor is when working fluid entering through the inlet side of the pump, moved by the rotor screw through the sidelines of the outer side. Upon reaching the outlet side, the fluid will be pushed out of the pump.

    • Progressive Cavity Pump

    This type of pump is the development of a screw type pump. The working principle was first introduced by Rene Moineau in the 1930s. The pump consists of both helical rotor and stator, but the stator designed to have a spiral pitch distance which is 2 times larger than the pitch of the rotor. The progressive cavity pump rotor is connected to the shaft driven by an electric motor. Among the shafts with the rotor is connected by flexible coupling which when the shaft rotates, this clutch moves to follow the movement of the rotor and shaft. For more details please note the following animation.

    Progressive Cavity Pump (Source: Wikipedia)

    Spiral design of the rotor and stator form a cavity (cavities) in it, which is when the rotor cavity as if it moved toward the pump outlet. This space is the space to move the working fluid.


    Progressive Cavity Pump Parts

    Progressive cavity pumps can be used in various types of working fluids, from dilute fluids to high-viscosity fluids. However, this pump does not match the solid particles. For operational purposes, this pump needs to be carried out a priming process as well as discharge of air trapped (venting) in it before operating. It aims to extend the life of the pump.

    • Rotary Lobe Pump and Rotary Piston Pump

    The rotary lobe pump is similar to a gear pump, it’s just using a kind of lobe-shaped rotor. There are two lobe rotor inside the pump casing, which are both driven by a driving source and arranged by gear that is outside the body of the pump so that the rotor rotates in rhythm. The rotation of the rotor gives rise to empty space so that the fluid can enter into it and move to the outlet side. On the outlet side the two rotor lobes meet so close the existing cavity and push the working fluid out through the pump outlet.

    Rotary Lobe Pump

    Rotary piston pump is the development of a rotary lobe pump. The rotary piston pump rotors are designed in such a way that the pump cavity volume becomes wider. In addition to the pump outlet side, the pump rotor no longer “squeezes” the working fluid out as in the rotary lobe pump, but the rotary piston pump rotation shape will push the fluid out to the outlet side of the pump.


    Rotary Piston Pump
    • Vane Pump

    This rotary pump uses a cylinder in the rotor section, a spring-mounted cylinder base connected to the pump rotor. The rotor axis is not aligned with the pump casing axis, so that when the rotor rotates, the rotor cylinder will follow the shape of the casing and push the working fluid to the outlet.

    Vane Pump
    • Peristaltic Pump

    The last rotary type is a peristaltic pump. This type of pump uses a working principle similar to the peristaltic movement of the esophagus. This pump uses a kind of elastic hose as a working fluid conduit. The hose is pressed by the rotor with the tip of the roller to form a push motion.


    Peristaltic Pump (Source: Wikipedia)

    Peristaltic pumps were initially widely used in laboratories only, but along with the development of rubber technology, current peristaltic pumps can be used for “heavy” materials including solid materials.

  2. Positive Displacement Reciprocating Pump
    The reciprocating pump uses a piston that moves back and forth as its working component, and directs the working fluid flow to only one direction with the help of a check valve. This positive displacement pump has a widespread work cavity during fluid sucking, and will push it by narrowing down the working cavity. With the help of check valve to regulate fluid flow direction, there will be harmonic pumping process.

    The reciprocating pump consists of several types:

    • Piston Pump

    This pump uses a piston to suck and push the working fluid. The number of pistons depends on the manufacturer’s design that adapts to the system requirements. The less number of pistons in the pump, the flow of water out will be more unstable. To obtain a stable fluid flow can be used pressure relief valve or pump with more pistons.


    • Plunger Pump

    This type of pump is similar to a piston pump. What distinguishes is not using a piston, the pump that drives the fluid does not fully fill the cylinder room. For more details see the picture of the difference between the piston pump with the following plunger pump.

    • Diaphragm Pumps

    The pump is also similar to the piston pump but the pump component that performs the back and forth motion is the diaphragm connected to the crank of the drive. The diaphragm will move forward and backward to create changes in the space cavity inside the pump. With the help of check valve then the fluid flow of work can occur.


    Diaphragm pumps generally operate at lower pressures than piston or plunger pumps. However, because of its unique design, the diaphragm pump can continue to operate even when there is no fluid flowing in it. And automatically when the working fluid is available again, this pump can naturally primed and vented.

    • Swashplate Pump

    The last type of pump we will discuss is a swashplate pump. This pump is the development of the piston pump. Some pistons are arranged parallel to the one end connected with the upright plate, while the other end is connected to the sloping plate. As the pump shaft rotates the parallel piston-piston rotates to produce a movement back and forth. To better understand this type of pump, let’s consider the following animated video.

    What is interesting about this pump is that the fluid flow discharge can be greatly changed. This can be done by altering the angle of the slope of the plate connected to the pump pistons.

Pumps Classification

In general, pumps are classified into two major groups, the dynamic pump and positive displacement pump. These two big groups are divided into few more.

Dynamic Pump

Dynamic pump is divided into several kinds, centrifugal pumps, axial pumps, and special-effect pumps. These pumps generate high fluid velocity by converting velocity into pressure through the changes of cross-sectional fluid flow. This type of pump has lower efficiency than positive displacement pump, but has lower cost in maintenance. Dynamic pumps can also operate at high speeds and high flow discharge.

  1. Centrifugal Pump

  2. Centrifugal pump composed of an impeller with inlet channel in the middle. With this design, when the impeller rotates, fluid flows into the pump casing around the impeller as a result of centrifugal force. This casing decreases the fluid flow velocity while impeller rotation speed remains high. The fluid velocity is converted into pressure by the casing so that the fluid can reach its outlet point. Centrifugal pump has some advantages include smooth operation in pumps, uniform pressure at pump discharge, low cost, and can work at high speeds so that further applications can be connected directly with steam turbines or electric motors. The use of centrifugal pumps in the world reaches 80% because of its suitable use to cope with large amounts of fluid than positive-displacement pumps.

    Centrifugal Pump
  3. Axial Pumps
  4. Axial pump is also called propeller pump. This pump produces most of the pressure and lifting force from the propeller. These pumps are widely used in drainage and irrigation systems. Single-stage vertical axial pumps are more commonly used, but sometimes two-stage axial pumps are more economical to implement. Horizontal axial pumps are used for large fluid flow discharge with small pressure and usually involve the siphon effect in the flow.

    Axial Pump
  5. Special-Effect Pump
  6. This type of pump used in industries with certain conditions. This type of pump are jet-eductor, gas lift, hydraulic ram, and electromagnetic.

    Jet-eductor pump is using venturi effect of a convergent-diverging nozzle to convert pressure energy from moving fluid to motion energy to create a low pressure area, than can suck fluid on the suction side.

    Injector Pump

    Gas Lift Pump is a way to lift fluid inside a column by injecting a certain gas causing the drop of hydrostatic weight from the fluid so that the reservoir can lift it to the surface.

    The hydraulic ram pump is a cyclic water pump using hydropower.

    And an electromagnetic pump is a pump that drives metal fluids by using electromagnetic forces.

    Electromagnetic Pump

Positive Displacement Pump

Positive displacement pumps are devided into reciprocating and rotary pumps. The positive displacement pump works by assigning a certain force to the fixed fluid volume from the inlet side to the pump outlet point. The advantages of using this type of pump is that it can produce a larger power density, and also provides fluid displacement that is fixed/stable in every turn.

  1. Reciprocating Pumps
  2. At this type of pump, a certain amount of fluid volume enters the cylinder through the inlet valve at entry step and then pumped out under positive pressure through the valve outlet in a step forward. The fluid coming out of the reciprocating pump, pulsating and can only change when the pumping speed changes. This is because the volume of the inlet side is constant. This type of pump is widely used for pumping sediment and sludge.

    Reciprocating Pump

    Metering Pump is included in the reciprocating pump type. This pump can varied the fluid pressure discharge as needed. Metering pumps typically used to pump additives inserted into a particular fluid stream.

    Metering Pump
  3. Rotary Pump
  4. Is a pump that drives the fluid by using the principle of rotation. The vacuum is formed by the rotation of the pump and then sucks the incoming fluid. The advantage of this type is its high efficiency because it naturally removes air from its flow pipe, and reduces the user’s need to manually remove the air.

    This pump weakness is, because of its natural design, the clearence between the swivel blade and the follower blade should be as small as possible. It’s also has requirement to rotate at low and stable speed. If the pump is working at a very high speed, then the working fluid can eroded the pump blades.

    Rotary pumps can be classified into several types:

    • Gear pumps – a simple rotary pump where the fluid is pressed using two gears.
    Gear Pump
    • Screw pumps – These pumps use two threads that meet and rotate to produce the desired fluid flow.
    Screw Pump
    • Rotary Vane Pump – has the same principle as a scroll compressor, which uses a rotating cylindric rotor to produce a certain fluid pressure.
    Rotary Vane Pump

    More details about the various positive displacement pumps, you can open the following article.