Engine external combustion principle. Internal combustion engine - creating history. Stirling Modifications "Beta"

In engines external combustion The process of burning fuel and the source of thermal exposure is separated from the work unit. This category usually includes steam and gas turbines, as well as stirling engines. The first prototypes of such installations were designed for more than two centuries ago and used throughout almost the XIX century.

When powerful and economical energy installations were needed for the rapidly developing industry, the designers came up with replacement with explosive steam engines, where the working body was under high pressure of steam. So there were external combustion engines that have been distributed at the beginning of the XIX century. Only in a few decades the engines came to shift internal combustion. They cost significantly cheaper as their widespread.

But today the designers are increasingly looking at the external combustion engines released from the widespread use. This is explained by their advantages. The main advantage is that such installations do not need well cleaned and expensive fuel.

External combustion engines are unpretentious, although so far their building and maintenance costs quite expensive.

Stirling's engine

One of the most famous representatives of the family of external combustion engines is a stirling machine. She was invented in 1816, it was repeatedly improved, but afterwards for a long time it was undeservedly forgotten. Now the stirling engine received the second birth. It is successfully used even when exploring the outer space.

The work of the stirling machine is based on a closed thermodynamic cycle. Periodic compression and expansion processes here go at different temperatures. The workflow control occurs by changing its volume.

Stirling engine can operate as a heat pump, pressure generator, cooling devices.

In this engine at a low temperature there is a gas compression, and with high - its expansion. Periodic change in parameters occurs due to the use of a special piston having a function of the displacer. Heat to the working fluid at the same time is supplied with outside, through the wall of the cylinder. This feature gives the right

Despite their high performance modern engine Internal combustion begins to obstruct. His to. P. D. reached, perhaps, its limit. The noise, the vibration, poisoning air gases and other disadvantages inherent in it make scientists look for new decisions, revise the possibilities of a long time "forgotten" cycles. One of the "revived" engines is stirring.

Back in 1816, the Scottish priest and scientist Robert Stirling patented the engine in which fuel and air entering the combustion zone, never fall inside the cylinder. They burn, just heating the working gas located in it. This gave reason to name the invention of stirling by an external combustion engine.

Robert Stirling built several engines; The last one had a capacity of 45 liters. from. And worked at the mine in England for more than three years (until 1847). These engines were very heavy, occupied a lot of space and outwardly resembled steam vehicles.

For navigation, external combustion engines were first applied in 1851 by Swede John Erickson. The Erickson vessel constructed by them safely crossed the Atlantic Ocean from America to England with a power plant consisting of four external combustion engines. In the age of steam machines it was a sensation. but power point Erickson developed only 300 liters. with., not 1000, as expected. The engines had huge sizes (cylinder diameter 4.2 m, piston stroke 1.8 m). Coal consumption turned out to be no less than in steam machines. When the vessel came to England, it turned out that the engines are not suitable for further operation, since they struggled the bottoms of cylinders. To return to America, I had to replace the engines with a regular steam engine. On the way back the ship fell into an accident and sank with all the crew.

Low-rise external combustion engines at the end of the last century were used in houses for pumping water, in printing houses, at industrial enterprises, including at the St. Petersburg Nobel Plant (now "Russian diesel"), they were installed in small courts. Stirling was produced in many countries, including in Russia, where they were called "Heat and Strength". They appreciated them for the sneaky and safety of the work than they have differed from the steam vehicles.

With the development of internal combustion engines for stirlings forgotten. In the encyclopedic dictionary, Brockaua and Efron, the following is written about them: "Safety from explosions is the main favorable side of the caloric machines, thanks to which they can get into use if they find new materials better to build and lubricating them."

The case was, however, not only in the absence of relevant materials. There were still unknown, modern principles of thermodynamics, in particular the equivalence of heat and work, without which it was impossible to determine the greatest ratios of the main elements of the engine. Heat exchangers made with a small surface, because of which the engines worked with progenially high temperatures And quickly failed.

Attempts to improve stirring were taken after World War II. The most essential of them were that the working gas began to be applied compressed to 100 atm and use no air, but hydrogen having a higher thermal conductivity coefficient, low viscosity and, moreover, not oxidizing lubricants.

Device of an external combustion engine in its modern video schematically shown in Fig. 1. In closed on one side, the cylinder is two pistons. Upper - piston-in-Purpose to accelerate the process of periodic heating and cooling of the operating gas. It is a hollow closed stainless steel cylinder, poorly conductive heat, and moves under the action of a rod associated with a crank-connecting mechanism.

The lower piston is a worker (in the figure is shown in cross section). It transmits the effort to the crank-connecting mechanism through the hollow rod, inside which the oscillator rod passes. The working piston is equipped with sealing rings.

Under the working piston there is a buffer container, forming a pillow that performs the flywheel function - smooth out the irregularity of the torque due to the selection of the energy of the energy during the working stroke and returning it to the motor shaft during the compression stroke. To insulate the volume of the cylinder from the surrounding space, serve a "wrapping stocking" type. These are rubber tubes attached by one end to the rod, and the other to the case.

The top of the cylinder comes into contact with the heater, and the bottom - with the refrigerator. Accordingly, it is distinguished by "hot" and "cold" volumes that are freely reported by means of a pipeline in which the regenerator is located (heat exchanger). The regenerator is filled with a grinding with a small diameter wire (0.2 mm) and has a high heat capacity (for example, to. P. D. Filipe regenerators exceed 95%).

The workflow of the stirling engine can be carried out without a displacement, based on the use of the operating charge spool distributor.

In the lower part of the engine there is a crank-connecting mechanism, which serves to convert the reciprocating movement of the piston into the rotational movement of the shaft. A feature of this mechanism is the presence of two crankshaftsconnected by two gears with spiral teeth rolling towards each other. The rod of the oscillator is associated with the crankshafts through the lower rocker and trailed connecting rods. The working piston rod connects to the crankshafts through the top rocker and trailed connecting rods. The system of identical connecting rods forms a movable deformable rhombus, from where and the name of this transmission is rhombic. Rhombic transmission provides the necessary phase shift when the piston moves. It is completely balanced, it does not arise lateral efforts on piston rods.

In space, limited, working piston, is a working gas - hydrogen or helium. The total volume of gas in the cylinder does not depend on the position of the displacer. Changes in volume associated with compression and expansion of the working gas occur due to the movement of the working piston.

When the engine is running, the upper part of the cylinder is constantly heated, for example, from the combustion chamber, into which liquid fuel is injected. The lower part of the cylinder is constantly cooled, for example, with cold water, pumped through a water shirt surrounding the cylinder. A closed stirling cycle consists of four clocks shown in Fig. 2.

Tact I - cooling. The working piston is in the extreme lower position, the displacer moves up. At the same time, the working gas flows from the "hot" volume over the displacer in the "cold" volume under it. Passing along the path through the regenerator, the working gas gives him a part of his heat, and then cooled in the "cold" volume.

Tact II - Compression. The displacer remains in the upper position, the working piston moves up, squeezing the working gas at low temperatures.

Tact III - Heating. The working piston is in the upper position, the displacer moves down. At the same time, a compressed cold working gas rushes from under the displacer to the liberating space above it. On the road, the working gas passes through the regenerator, where it is preheated, it falls into the "hot" cavity of the cylinder and heats up even stronger.

Tact IV - Extension (Working). Heating, the working gas expands, while moving the displacer and with it a working piston down. Performed useful work.

Stirling has a closed cylinder. In fig. 3, and a diagram of the theoretical cycle (diagram V - P) is shown. According to the abscissa axis, the volume of the cylinder is postponed, along the axis of the ordinate - pressure in the cylinder. The first tact is isothermal I-II, the second occurs at a constant volume of II-III, the third isothermal III-IV, the fourth - with a constant amount of IV-I. Since the pressure during the expansion of hot gas (III-IV) is greater than the pressure during the compression of cold gas (I-II), then the work of expansion is more compression work. The useful operation of the cycle can be graphically portrayed in the form of a curvilinear quadrangle I-II-III-IV.

In the actual process, the piston and the displacer move continuously, since they are associated with a crank-connecting mechanism, so the diagram of the valid cycle is rounded (Fig. 3, b).

Theoretical to. P. D. Stirling engine is 70%. Studies have shown that in practice it is possible to obtain a k. P. D., Equal to 50%. This is significantly more than the best gas turbines (28%), gasoline engines (30%) and diesel engines (40%).

Stirling can work on gasoline, kerosene, diesel, gaseous and even solid fuel. Compared to other engines, it has a softer and almost silent course. It is explained by this low compression ratio (1.3 ÷ 1.5), moreover, the pressure in the cylinder increases smoothly, and not an explosion. Combustion products are also available without noise, as the combustion occurs constantly. They are relatively few toxic components in them, because the combustion of fuel occurs continuously and with constant excess of oxygen (α \u003d 1,3).

Stirling with rhombic transmission is completely balanced, vibrations do not occur in it. This quality, in particular, was taken into account by American engineers who have established a single-cylinder stirling on an artificial satellite of the Earth, where even small vibration and impassable can lead to loss of orientation.

One of the problematic issues remains cooling. In stirling with exhaust gases, only 9% of the heat obtained from fuel is given, so, for example, when installing it, it would have to make a radiator about 2.5 times more than when used gasoline engine The same power. The task is solved easier on ship installations, where efficient cooling is ensured by an unlimited amount of intricate water.

In fig. 4 shows a section of a two-cylinder boiler engine Philips with a capacity of 115 liters. from. With 3000 rpm with a horizontal position of cylinders. The total working volume of each cylinder is 263 cm 3. Pistons located oppositely are connected to two traverses, which allowed to fully equilibrate the gas forces and do without buffer volumes. The heater is made of tubes surrounding the combustion chamber for which the working gas passes. The cooler serves a tubular refrigerator through which the wounded water pumps. The engine has two crankshafts connected to the rowing shaft through worm gears. The height of the engine is only 500 mm, which allows it to be installed under flooring and thus reduce the dimensions of the machine compartment.

Stirling power is regulated mainly by changing the pressure of the working gas. At the same time, to maintain the temperature of the heater constant, and the fuel supply is also adjustable. Almost any sources of heat are suitable for the external combustion engine. It is important that it can turn low-temperature energy into useful operation, which are not capable of internal combustion engines. From the curve in fig. 5 It can be seen that at a heater temperature of only 350 ° C. C. P. Stirling is even equal to ≈ 20%.

Stirling is economical - the specific fuel consumption of it is only 150 g / l. from. hour. In the energy installation of the "engine stirling-battery", which is used on American Earth satellites, a thermal battery is a hydraulic lithium, which absorbs heat during the "lighting" period and gives it stirring when the satellite is on the shadow side of the Earth. On the satellite, the engine serves to drive a 3 kW generator with a capacity of 2400 rpm.

Created an experienced scooter with stirling and heat battery. The use of the heat and stirling battery on the submarine allows it to go in a submerged position several times longer.

Literature

• 1. Smirnov G.V. External combustion engines. "Knowledge", M., 1967.
• 2. Dr. IR. R. I. Meijer. Der Philips - Stirlingmotor, Mtz, N 7, 1968.
• 3. Curtis Anthony. Hot Air and the Wind of Change. The Stirling Engine and Its Revival. Motor (ENGL.), 1969, (135), N 3488.

Stirling engine, the principle of operation of which is qualitatively different from the usual for all of the Russian Federation, once amounted to the last worthy competition. However, for some time they forgot about him. As this motor is used today, what is the principle of its action (in the article you can also find the drawings of the Stirling engine, clearly demonstrating its work), and what are the prospects for use in the future, read below.

History

In 1816, in Scotland, Robert Stirling was patented today in honor of his inventor. The first hot air engines were invented before him. But Stirling added a cleaner into the device, which in the technical literature is called a regenerator, or a heat exchanger. Due to it, the engine performance increased when holding the unit in warmth.

The engine recognized the most sturdy steam machine from the at that time, since he never exploded. Before him, on other engines, such a problem occurred often. Despite the rapid success, at the beginning of the twentieth century, it was abandoned from its development, as it became less economical, compared with the other internal combustion engines that appeared then by other engines. However, stirling continued to be used in some industries.

Engine external combustion

The principle of operation of all thermal engines is that large mechanical efforts are needed to obtain gas in an extended state than when compressed cold. For a visual demonstration of this, you can spend experience with two saucepans filled with cold and hot water, as well as a bottle. The latter is lowered into cold water, plug through the plug, then transferred to hot. In this case, gas in the bottle will start performing mechanical work and pushes a plug. The first external combustion engine was based on this process completely. True, later the inventor understood that part of the heat can be used for heating. Thus, performance has increased significantly. But even this did not help the engine to become common.

Later, Erickson, engineer from Sweden, improved the design, offering cooling and heat the gas at a constant pressure instead of volume. As a result, many copies began to be used to work in mines, on ships and in printing houses. But for the crews they were too heavy.

PHILIPS external combustion engines

Such motors are the following types:

• steam;
• parroid turbine;
• Stirling.

The latter view did not develop because of the slight reliability and other not the highest rates compared to the other types of aggregates appeared. However, in 1938, Philips resumed work. Engines began to serve for drives of generators in inelectricated areas. In 1945, the company's engineers found them inverse use: if the shaft is uninstalled by an electric motor, then the cooling of the cylinder head comes to minus one hundred ninety degrees Celsius. Then it was decided to apply an improved stirling engine in refrigeration plants.

Principle of operation

The motor action lies in the thermodynamic cycles, in which compression and expansion occurs at different temperatures. At the same time, the regulation of the working fluid stream is implemented due to the varying volume (or pressure - depending on the model). This is the principle of the work of the majority similar machineswhich may have different functions and constructive schemes. Engines can be piston or rotary. Machines with their installations work as heat pumps, refrigerators, pressure generators and so on.

In addition, there are motors with an open cycle, where the flow control is implemented by valve. It is them called Erikson engines, except for the overall name of the Schirling name. In ICC, useful work is carried out after pre-compression of air, fuel injection, heating the mixture of the mixture to combustion and expansion.

Stirling engine The principle of operation is the same: at low temperatures, compression occurs, and with high expansion. But in different ways heating is carried out: heat is supplied through the cylinder wall from the outside. Therefore, he received the name of the engine of external combustion. Stirling used periodic change in temperature with a displacement piston. The latter moves gas from one cylinder cavity to another. On the one hand, the temperature is constantly low, and on the other - high. When the piston moves up, the gas moves from hot to the cold cavity, and down - returns to hot. First, the gas gives a lot of heat to the refrigerator, and then from the heater gets as much as I gave. A regenerator is placed between the heater and the refrigerator - the cavity filled with the material that gas gives heat. With reverse course, the regenerator returns it.

The displacement system is connected to a working piston compressing gas in the cold and allowing to expand warm. Due to the compression at a lower temperature, useful work occurs. The whole system passes four cycles during intermittent movements. The crank-connecting mechanism in this case provides continuity. Therefore, sharp boundaries between the stages of the cycle are not observed, and the stirling does not decrease.

Considering all of the above, it suggests that this engine is a piston machine with an external heat supply, where the working fluid does not leave the closed space and is not replaced. Stirling engine drawings well illustrate the device and the principle of its action.

Details of work

The sun, electricity, nuclear energy or any other heat source can supply energy into the stirling engine. The principle of its body is to use helium, hydrogen or air. The ideal cycle has the thermal maximum possible efficiency equal to thirty to forty percent. But with an effective regenerator, he will be able to work with more high efficiency. Regeneration, heating and cooling provide built-in heat exchangers working without oils. It should be noted that the engine lubricants need very little. The average pressure in the cylinder is usually from 10 to 20 MPa. Therefore, there is an excellent sealing system and the possibility of oil entering workers.

Comparative characteristics

Most of the engines of this kind are used today, liquid fuel is used. At the same time, continuous pressure is easy to control, which helps to reduce emissions. The absence of valves provides silent operation. Power with mass is comparable to turbocharged motors, and the specific power obtained at the output is equal to the indicator of the diesel unit. Speed \u200b\u200band torque do not depend on each other.

The cost of the engine production is much higher than on the engine. But when operating it turns out the reverse figure.

Benefits

Any model of stirling engine has many advantages:

• The efficiency in modern design can reach up to seventy interest.
• There is no system in the engine high voltage ignition, distribution Vala. and valves. It will not need to be adjusted throughout the service life.
• There is no explosion in stirlings, as in the internal combustion engine, which greatly loads the crankshaft, bearings and connecting rods.
• They do not have the effect when they say that the "engine stall".
• Due to the simplicity of the device, it can be operated for a long time.
• It can work both on firewood and with nuclear and any other fuel type.
• Combustion occurs outside the motor.

disadvantages

Application

Currently, the stirling engine with the generator is used in many areas. This is a universal source of electrical energy in refrigerators, pumps, submarines and solar electric stations. Thanks to the application of various types Fuel is available to its wide use.

Revival

These engines began to develop again thanks to Philips. In the middle of the twentieth century, General Motors concluded with her. She led the development for the use of stirlings in space and underwater devices, on ships and cars. Following them, another company from Sweden, United Stirling, began to engage in their development, including possible use on

Today linear engine Stirling is applied on installations of underwater, cosmic and solar apparatuses. A great interest in it is caused by the relevance of the worsening environmental situation, as well as the fight against noise. In Canada and the USA, Germany and France, and Japan are active search for the development and improvement of its use.

Future

Explicit advantages that have piston and stirling, consisting in a large resource of work, the use of different fuel, silentness and low toxicity, make it very promising against the background of the internal combustion motor. However, taking into account the fact that ICE has been improved throughout the time, it cannot be easily displaced. One way or another, it is such an engine today occupies a leading position, and they do not intend to take them in the near future.

External combustion engines began to be used when people needed a powerful and economical source of energy. Prior to that, steam installations were used, but they were explosive, since they used hot steam under pressure. In the early 19th century, they received devices with external combustion, and after another tens of years, already familiar devices with internal combustion were invented.

Origin of devices

In the 19th century, humanity faced the problem, which was that the steam boilers were too often exploded, and also had serious constructive flaws, which made their use undesirable. The output was found in 1816 by the Scottish priest Robert Stirling. These devices can also be called "hot air engines", which were still applied in the 17th century, but this man added a cleaner called the regenerator currently called the invention. Thus, the engine external combustion engine was able to greatly increase the performance of the installation, as it retained heat in the warm working area, while the working fluid was cooled. Because of this, the efficiency of the entire system was significantly increased.

At that time, the invention was used quite widely and was on the rise of its popularity, but over time it was stopped using it, and they forgot about him. Steam installations and engines, but already familiar, with internal combustion, came to replace the equipment of external combustion. Again, they remembered only in the 20th century.

Installation work

The principle of operation of an external combustion engine is that it constantly alternates two stages: heating and cooling of the working fluid in a closed space and energy obtaining. This energy arises due to the fact that the volume of the working fluid is constantly changing.

Most often, the working substance in such devices becomes air, but it is possible to use a helium or hydrogen. At that time, the invention was at the development stage, such substances as nitrogen dioxide, freons, liquefied propane-butane were used as experiments. In some samples, they tried to apply even ordinary water. It should be noted that the external combustion engine, which was launched with water as a working substance, was distinguished by the fact that he had a fairly high specific power, high pressureAnd he himself was compact enough.

The first type of engine. "Alpha"

The first model that was used, became Alpha Stirling. The peculiarity of its design is that it has two power pistons located in different in separate cylinders. One of them had a sufficiently high temperature and was hot, the other, on the contrary, cold. Inside the heat exchanger with a high temperature there was a hot pair of cylinder-piston. Cold steam was inside the heat exchanger with low temperatures.

The main advantages of the thermal engine of external combustion was the fact that they had high power and volume. However, the temperature of the hot pair at the same time was too large. Because of this, some technical difficulties arose in the process of manufacturing such inventions. The regenerator of this device is between hot and cold connecting tubes.

Second sample. "Beta"

The second sample was the Beta Stirling model. The main constructive difference was that there was only one cylinder. One of his ends served as a hot pair, and the other end remained cold. Inside this cylinder, the piston was moved from which the power can be removed. Also inside there was a displacer, which was responsible for changing the volume of the hot work area. In this equipment, gas was used, which was pumped from a cold zone to hot through the regenerator. This type of external combustion engine possessed a regenerator in the form of an external heat exchanger or combined with the piston-displacer.

Latest model. "Gamma"

Last species this engine Steel "Gamma" Stirling. This type differed not only by the presence of the piston, as well as the displacer, and also the fact that two cylinders were already in its design. As in the first case, one of them was cold and it was used to take power. But the second cylinder, as in the previous case, was cold from one end and hot from the other. Here displaced the displacer. IN piston Engine External combustion also had a regenerator who could be two types. In the first case, it was external and connected together such structural parts as a hot cylinder zone with cold, as well as with the first cylinder. The second type is an internal regenerator. If this option was used, it was included in the design of the displacer.

The use of stirlings is justified if a simple and small thermal energy converter is needed. It can also be used if the temperature difference is not high enough to use gas or steam turbines. It is worth noting that today such samples began to be used more often. For example, autonomous models for tourists are used, which are capable of working from gas burner.

Application of devices at present

It would seem that such an old invention cannot be used in our days, but it is not. NASA ordered an external combustion engine of the Stirling type, but nuclear and radioisotope heat sources should be used as a working substance. In addition, it can also be successfully used for the following purposes:

• Use such an engine model to pump liquid is much easier than the usual pump. In many ways, this is due to the fact that the piston can be used the pumped liquid itself. In addition, it will cool the working body. For example, this kind of "pump" can be used to pump water into irrigation channels using solar heat for this.
• Some manufacturers of refrigerators are inclined to install such devices. The cost of products will be able to reduce, and as refrigerant can be used ordinary air.
• If you combine the external combustion engine of this type with the heat pump, you can optimize the operation of the thermal network in the house.
• Pretty successfully stirlings are used on submarines of the Navy Sweden. The fact is that the engine works on liquid oxygen, which is subsequently used for breathing. For a submarine, this is very important. In addition, such equipment has a fairly low noise level. Of course, the unit is large enough and requires cooling, but it is these two factors that are insignificant if we are talking about a submarine.

Advantages of using the engine

If we use modern methods during the design and assembly, then it will be possible to raise the efficiency of the external combustion engine to 70%. The use of such samples is accompanied by the following positive qualities:

• Surprisingly, the torque in this invention is almost independent of the rotation speed of the crankshaft.
• In this force aggregate There are no elements such as the ignition system and the valve system. There is also no camshaft here.
• It is quite convenient that throughout the period of use, it will not be necessary to adjust the equipment and configure equipment.
• Engine model data is not able to "stall". The simplest design of the device allows you to use it quite a long time in a fully offline mode.
• You can use almost everything from the firewood and ending with uranium fuel as a source of energy.
• Naturally, in the external combustion engine, the burning process of substances is carried out outside. This contributes to the fact that the fuel is in full, and the amount of toxic emissions is minimized.

disadvantages

Naturally, any invention is not devotioned. If we talk about the minuses of such engines, then they are as follows:

1. Due to the fact that the combustion is carried out outside the engine, the removal of the resulting heat occurs through the walls of the radiator. This forces to increase the dimensions of the device.
2. Material consumption. In order to create a compact and efficient engine model Stirling, it is necessary to have high-quality heat-resistant steel that can withstand a large pressure and high temperature. In addition, there must be low thermal conductivity.
3. As a lubricant will have to buy special toolSince the usual cocks at high temperatures, which are achieved in the engine.
4. To obtain a sufficiently high specific power, it is necessary to use either hydrogen or helium as a working substance.

Hydrogen and helium as fuel

Obtaining high powerOf course, it is necessary, however, it is necessary to understand that the use of hydrogen or helium is quite dangerous. Hydrogen, for example, itself is sufficiently explosive, and at high temperatures it creates connections called metalhydrites. This happens when hydrogen is dissolved in the metal. In other words, it is able to destroy the cylinder from the inside.

In addition, hydrogen, and helium are volatile substances that are characterized by a high penetrating ability. If it is easier to speak, then they are easily seeping through almost any seals. And the loss of the substance means losses in the operating pressure.

Rotary external combustion engine

The heart of such a car is a rotary expansion machine. For engines S. external type Combustion This element is represented in the form of a hollow cylinder, which is covered with covers on both sides. By itself, the rotor has the appearance of the wheel, which is planted on the shaft. It also has a certain amount of P-shaped extended plates. For their extension, a special retractable device is used.

External combustion engine Lukyanova

Yuri Lukyanov is a researcher of the Pskov Polytechnic Institute. He has long been developing new models of engines. The scientist tried to make such elements such as the gearbox, camshaft and exhaust pipe in the new models. The main disadvantage of Stirling devices was that they had too large dimensions. It was this lack of a scientist and managed to eliminate due to the fact that the blades were replaced by pistons. It helped to reduce the size of the entire design several times. Some suggest that you can make an external combustion engine with your own hands.

Engines of external combustion

An important element of the implementation of the energy saving program is to provide autonomous sources of electricity and heat of small residential entities and remote from centralized networks of consumers. To solve these tasks, innovative installations for generating electricity and heat based on external combustion engines are best suited. As a fuel, both traditional fuels can be used and associated petroleum gas, biogas obtained from wood chips, etc.

Over the past 10 years, increased prices for fossil fuels, increased attention to CO 2 emissions, as well as a growing desire to stop depending on fossil fuels and fully ensure itself with energy. This was the consequence of the development of a huge technology market capable of producing biomass energy.

External combustion engines were invented almost 200 years ago, in 1816. Together with the steam engine, a two-and four-stroke engine of internal combustion, external combustion engines are considered one of the main types of engines. They were designed to create engines that would be safer and more productive than the steam engine. At the very beginning of the 18th century, the lack of suitable materials led to numerous deaths due to explosions steam enginesPressure.

The significant market for external combustion engines was formed in the second half of the 18th century, in particular, due to smaller applications, where they could be safely operated without the need for skilled operators.

After the invention of the internal combustion engine at the end of the 18th century, the market for external combustion engines disappeared. The cost of producing an internal combustion engine in comparison with the cost of production of external combustion is lower. The main disadvantage of internal combustion engines is that for their work it is necessary to clean, fossil fuel, increasing CO2 emissions, fuel. However, until recently, the cost of fossil fuels was low, and CO2 emissions did not pay due attention.

Principle of External Combustion Engine

In contrast to the widely known process of internal combustion, in which the fuel is burned inside the engine, the external combustion engine is driven by an external heat source. Or, more precisely, it is driven by the temperature differences created by external sources Heating and cooling.

These external sources of heating and cooling can serve the exhaust gases of biomass and cooling water, respectively. The process leads to a rotation of the generator mounted on the engine, whereby energy is produced.

All internal combustion engines are powered by temperature differences. Petrol diesel engines And the external combustion engines are based on the features that there is less effort to compress cold air than to compress hot air.

Gasoline and diesel engines suck the cold air and compress this air before it is heated in the process of internal combustion, which occurs inside the cylinder. After heating the air above the piston, the piston moves down, whereby the air expands. Since the air is hot, the force acting on the rod of the piston is great. When the piston comes to bottom, the valves open and hot exhausts are replaced with new, fresh, cold air. When the piston moves up the cold air is compressed, and the force acting on the piston rod is less than when it moves down.

External combustion engine works in accordance with a little different principle. It has no valves, it is hermetically sealed, and the air is heated and cooled with the help of heat exchangers of a hot and cold circuit. The built-in pump driven by the movement of the piston provides air movement there and back between these two heat exchangers. During the cooling of the air in the heat exchange apparatus of the cold circuit, the piston compresses the air.

After compression, the air is then heated in the heat exchange apparatus of the hot contour, before the piston begins to move in the opposite direction and use the extension of hot air to actuate the engine.