RU2703114C1 - Device for conversion of chemical energy of fuel-air mixture into electric energy (versions) - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to propulsion engineering, namely, to devices of internal combustion engines with free piston. Disclosed is an device for converting chemical energy of a fuel-air mixture into an electrical one, comprising a cylinder, a free piston configured to reciprocate in a cylinder provided with inlet and outlet valves, an electromagnetic system, wherein the cylinder is free, the electromagnetic system comprises magnets, electric windings and a magnetic conductor, wherein the magnets or the magnetic conductor are located on the free piston, electric windings with the magnetic conductor or magnets with electric windings are installed on the free cylinder. A version is considered, in which the cylinder is made free, the electromagnetic system contains magnets, electric windings and a magnetic conductor, at that, magnets or magnetic conductor are installed on free cylinder, and electric windings with magnetic conductor or magnets with electric windings are arranged in annular system around free cylinder. A version is considered, in which the device for conversion of chemical energy of fuel-air mixture into electric one includes a housing, a rotor made with possibility of oscillating-rotational movement in the housing equipped with inlet and outlet valves, electromagnetic system, wherein rotor and housing are free, free rotor is connected to annular system, wherein annular system and free housing are equipped with electromagnetic system.

EFFECT: invention provides for higher level of balance in operation of electric generator, simplified design, increased degree of compression of fuel-air mixture from 50 and higher, increased efficiency at operation at mixtures of poor composition.

6 cl, 3 dwg, 1 tbl

Description

The invention relates to mechanical engineering and the electric power industry, in particular to engine building, and in particular, to devices for converting chemical energy into electrical energy, in particular, to internal combustion engines (ICE).

Currently, there is an acute problem of creating mobile autonomous mini-power plants and new generation electric generators that efficiently use the energy of liquid and gaseous hydrocarbon fuels, including biogas and other low-calorie fuels.

Numerous methods are known for converting chemical energy into electrical energy, including by burning hydrocarbon and other fuels in internal combustion engines.

Currently used various mobile autonomous mini-power plants are technical devices in the form of two independent units, providing in conjunction conversion of fossil fuel energy into electricity [1]. The first block is a piston internal combustion engine (ICE), the second block is the actual electric generator. This arrangement has significant disadvantages. The specific gravity of the power unit reaches a large value of ~ 20 kg / kW. Note that widely used power units are not able to operate on low-calorie fuel, in particular, biogas.

Recently, new devices have been developed for converting chemical energy into electrical energy on the basis of a monoenergoblock built on the basis of a linear internal combustion engine with a free piston [2-5]. Permanent magnets are mounted on the movable piston, and electric coils are placed on a fixed housing. When a piston with magnets moves inside the coils, electrical energy is generated. According to its energy characteristics, such an internal combustion electric generator (EHWS) is much superior to a two-unit power plant, and in terms of efficiency it approaches fuel cells. Other important advantages of the EHF of this design for energy conversion:

- reducing the number of moving parts due to the exclusion of the crankshaft and connecting rods, which are included in the design of the internal combustion engine;

- increasing the rigidity and mechanical reliability of the engine structure;

- increased resource and mechanical efficiency of the engine due to simplification of the design;

- the ability to dynamically change the degree of compression during operation not by mechanical means, but by setting the parameters of the control system. Ability to work at high compression ratios;

- the ability to work with various types of fuel, including low-calorific fuel and mixtures of poor composition;

- implementation of various ignition and fuel combustion modes;

- the exception of the starter to start the internal combustion engine, since due to the reversible action of the generator, the system has the self-starting property;

- reduction of production costs.

By its energy characteristics, such an internal combustion electric generator is much superior to a two-unit power plant, and in terms of efficiency ~ 40% it approaches fuel cells.

It becomes possible to use the modular design of the propulsion system in the form of several distributed units, which leads to new principles of vehicle layout, and also increases its reliability when used in military and other critical areas of transport equipment.

However, the designs given in [2-5] have significant drawbacks. The main ones are:

1. The danger of collision of pistons in a two-piston generator circuit or impact of a piston on the cylinder end in a single-piston generator circuit in some operating modes with a high compression ratio. In a conventional internal combustion engine, the top dead center of the piston path is defined by the geometry of the crank mechanism, and in an internal combustion engine with a free piston it depends on the degree of compression and the rate of combustion of the air-fuel mixture. That is, the piston is inhibited by the back pressure in the chamber. As a result, the cycle time and top dead center can vary. This means that if the nozzle malfunctions, the piston can hit the cylinder end. The possibility of a catastrophic shock of the movable piston against the cover of the fixed cylinder limits the compression ratio to about 20. For balanced engine operation, a special mechanism is also needed that would offset the difference in the processes of fuel combustion in each of the working volumes.

2. The EHM system with one free piston and two end combustion chambers is fundamentally unbalanced; therefore, the operation of such an EHM system occurs with strong vibrations if there is no massive base.

3. The EHF system with two free pistons moving in opposite directions and one central combustion chamber can theoretically be balanced. However, such a generator needs a complex electronic control system and motion correction of each piston to ensure their synchronous movement.

Thus, existing EHF systems require sophisticated electronic control and monitoring systems for the movement of the piston because of the fear of its impact on the cylinder cover, and in a design with two oppositely moving pistons in one cylinder, because of the complexity of organizing the synchronous movement of the pistons. These shortcomings limit the efficiency and the ability to work with very poor mixtures in the EHF system. Efficiency reduction is also due to the structural complexity of providing a very small gap between the piston magnets and the cylinder windings.

In [6], the design of a rotary-blade ICE consisting of an engine casing and two rotors — blades — which are locked by a locking device in the position of the rear wall of the combustion chamber, was proposed. An internal combustion engine is connected to electric motors-generators, while the rotor of one electric motor-generator is connected to one rotor of a rotary-vane internal combustion engine, the rotor of another electric motor-generator is connected to another rotor of a rotary-vane internal combustion engine, and the stators of electric motors-generators are connected to the body of the rotary-vane internal combustion engine. This design has a complex and inefficient two-block layout principle with separate internal combustion engines and electric generators.

In [7], the design of a free-piston ICE of a linear and rotary type was proposed for converting the chemical energy of the fuel-air mixture into mechanical energy. The known device [7] includes a free piston moving in a cylindrical body equipped with inlet and outlet valves and a mechanism for transferring energy to an external load, in which the cylindrical body is movable with the possibility of translational or rotational movement and is connected through unidirectional drives with two rotating in opposite directions by flywheels, interconnected and external load by a single transmission. In this design, the conversion of the chemical energy of the fuel-air mixture into mechanical energy is carried out by compressing and burning the fuel-air mixture in an internal combustion engine with a free piston or rotor, while mechanical work is performed when the combustion products expand and are removed into mechanical load through a free cylinder or engine body.

This design is complex and not effective, because it does not allow the direct conversion of chemical energy of the fuel-air mixture into electrical energy without the use of mechanical drives.

Closest to the proposed device are the design of the EHF based on a linear internal combustion engine [5] with one free piston and a fixed cylinder. It has all the above disadvantages inherent in EHF based on a linear internal combustion engine.

Thus, the technical problem to be solved is that the main drawback of existing internal combustion electric generators is a fundamental imbalance, which leads to strong vibrations during the operation of such an EHF, insufficient efficiency due to the limitation of the degree of compression and the inability to provide a small gap between the magnets on the piston and coils on the cylinder, for the balanced operation of existing generators requires complex control systems, which complicates their design, there are problems in operation Akiho installations on very poor mixtures composition.

The technical result consists in achieving a high level of balance in the operation of the claimed generator, simplifying the design, increasing the degree of compression of the fuel-air mixture from 50 and above, increasing efficiency to 50% and above, when working on mixtures of very poor composition,

The solution of the technical problem posed is achieved by the proposed device for converting the chemical energy of the fuel-air mixture into electric, including a cylinder, a free piston, made with the possibility of translational movement in a cylinder equipped with inlet and outlet valves, an electromagnetic system.

A distinctive feature of the device is that the cylinder is made free, the electromagnetic system contains magnets, electrical windings and a magnetic circuit, while the magnets or magnetic circuit are located on a free piston, electrical windings with a magnetic circuit or magnets with electrical windings are mounted on a free cylinder.

In another embodiment, a device for converting chemical energy of a fuel-air mixture into electrical energy includes a cylinder, a free piston made with the possibility of translational movement in a cylinder equipped with inlet and outlet valves, an electromagnetic system. A distinctive feature of the claimed device is that magnets or a magnetic circuit are mounted on a free cylinder, and electric windings with a magnetic circuit or magnets with electric windings are placed in an annular system around a free cylinder.

In another embodiment, a device for converting chemical energy of a fuel-air mixture into electrical energy includes a housing, a rotor made with the possibility of oscillatory-rotational movement in a housing equipped with inlet and outlet valves, an electromagnetic system. A distinctive feature of the claimed device in this embodiment is that the rotor and the housing are made free, the free rotor is connected to the ring system, and the ring system and the free case are equipped with an electromagnetic system.

The electromagnetic system of the device contains magnets, electrical windings and a magnetic circuit.

Magnets or a magnetic circuit in such a device are mounted on a free housing.

Electrical windings with a magnetic circuit or magnets with electrical windings in such a device are placed in an annular system around a free housing.

Below the invention is described in more detail by the example of several preferred options for its possible implementation (in linear and rotary versions) with reference to the accompanying drawings, which show:

in FIG. 1 is an axial section through a portion of a device made in accordance with the present invention (a linear version with an electromagnetic system). The device contains a free cylinder (1) and a free piston (2), a free cylinder (1) is equipped with inlet (3) and outlet (4) valves. The magnets (5) are located on the free piston (2), and the electrical windings with the magnetic circuit (6) are mounted on the free cylinder (1);

in FIG. 2 is an axial section through a portion of a device made in accordance with another embodiment (a linear embodiment with an electromagnetic system). The device contains a free cylinder (1) and a free piston (2), a free cylinder (1) is equipped with inlet (3) and outlet (4) valves. The magnetic circuit (6) is mounted on a free cylinder (1), magnets (5) with electric windings are placed in an annular system around a free cylinder (1);

in FIG. 3 is an axial section through a portion of a device made in accordance with another embodiment (rotary version with an electromagnetic system). The device contains a free housing (7) and a free rotor (8), a free housing (7) is equipped with inlet (3) and exhaust (4) valves, a magnetic circuit (6) is mounted on a free housing (7), magnets (5) with electrical windings are placed in a ring system around a free housing (7). The free rotor (8) is connected to the electromagnetic system.

In versions of the generator, when the magnetic circuit is mounted on a free piston and magnets with electric windings on a free cylinder, the design is greatly simplified, the reliability of the device is increased by improving the temperature regime for magnets.

The claimed device operates as follows.

The free piston (2) compresses air during its reciprocating movement, for example, in the left cavity of the device into which fuel is injected through the inlet valve (3) during the compression stroke. In the variant of adiabatic compression of a fuel-air mixture of poor composition, incapable of independent combustion, it is heated to a high temperature of the order of 1000 K. As a result of heating, the rate of chemical transformation reactions increases exponentially and there is a volumetric release of thermal energy, leading to an additional increase in pressure compressed gas. The free piston (2) and the free cylinder (1) begin to move in opposite directions. At the moment the piston passes the exhaust valve (4), the latter opens and the products of the chemical reaction flow from the left cavity and are purged with air through the opening inlet valve (3). The free piston (2) during its further movement performs a similar cycle in the right cavity of the device. A free piston (2) moves the magnets (5) or the magnetic circuit (6) in the cavity of the electromagnetic system, in which an electric current is transmitted to the load. Similarly, the energy of movement of the piston in the right direction is transmitted. The considered operating mode consists of two clock cycles: compression with fuel injection - a stroke with a purge. The device can also operate in four-cycle mode: purge-fuel injection - compression - stroke.

In the embodiments of the generator of FIG. 2, when the free piston (2) does not contain magnets (not shown in the figure), it plays the role of an inertial wall. The magnetic circuit (6) (or magnets (5)) is placed on a free cylinder (1), and the electrical windings with magnets (5) (or magnets (5) with a magnetic circuit (6)) are stationary and are placed in a ring system around a free cylinder (1) . In these embodiments, the magnets (5) are removed from the free cylinder (1) and this greatly simplifies the design and increases the reliability of the generator. The operation of the inlet (3) and outlet (4) valves occurs similarly to the embodiment of FIG. one.

Placing the electromagnetic system outside the free cylinder (1) can significantly reduce the gap between the moving parts of the electromagnetic system (up to 0.1 mm), which leads to an increase in magnetic flux, and, consequently, to an increase in the efficiency of conversion of chemical energy into electrical energy. The transfer of heavy magnets (5) and electric windings to the ring system around the free cylinder (1) significantly reduces the weight of the free piston (2) and free cylinder (1) (in the linear version), which leads to an increase in the frequency of their oscillations and, therefore, to an increase in efficiency conversion of chemical energy into electrical energy.

It is possible to implement a multi-cylinder system when combining and simultaneously using several similar devices when they work on a common load.

In the rotor version (Fig. 3), a free rotor (8) is connected to a movable ring electromagnetic system mounted around a free (movable) housing (7). In this embodiment, the magnets (5) are removed from the free housing (7) and this greatly simplifies the design, increases the reliability of the generator, and the connection of the free rotor (8) with a movable ring electromagnetic system ensures perfect balance of the generator.

The operation of the generator in the rotor version is similar to the operation of the generator described for the embodiment of FIG. 1. the free rotor (8) during its reverse-rotational movement compresses the air alternately in the left and right cavities of the device, which enters through the exhaust valve (4) and the corresponding inlet (3) valve. During the compression stroke, fuel is injected. A free housing (7) with a magnetic circuit (6) moves in the cavity of the electromagnetic system in which an electric current is transmitted to the load. The outflow of chemical reaction products occurs through the outlet valve (4) and the corresponding inlet (3) valve during the expansion stroke.

In the described constructions of the device there is no problem of hitting a free piston (rotor) against the head of a free cylinder (body) with a high degree of compression in case of a malfunction of the nozzle, since the cylinder (body) is also free. The serious problem of the electronic control of the internal combustion engine and the control of the fuel supply system is also removed. In essence, a scheme of an “ideal” balanced rotary electric generator is implemented with the only peculiarity that the movement of the “armature” and “stator” is due to the direct action of pressure from burning the air-fuel mixture. When the free cylinder or free housing is mutually moved with magnets (magnetic core) relatively stationary or connected to the rotor by the system of electrical windings or magnets with electrical windings, a change in the magnetic flux occurs, and EMF is induced in the electrical winding. Note that in both linear and rotary versions, the relative speed of the magnets relative to the electrical windings is higher compared to the version with a fixed electromagnetic system. This increases the effectiveness of EHF. In the rotor version, it is possible to supply a fresh mixture and release combustion products through a hollow shaft with window-type valves, which greatly simplifies and facilitates the design of the EHF.

The principal result of the tests carried out is the establishment of the possibility of direct, bypassing mechanical drives, converting the chemical energy of fuel into electrical energy.

In the proposed design, the chemical energy of the fuel when it is compressed and burned is converted into electrical energy during the mutual movement of a free cylinder or housing equipped with an electromagnetic system. There are options for linear and rotary EHF.

Our results made it possible to propose the design of an EHWS for converting the chemical energy of fuel-air mixtures into electric, fundamentally different from the known ones (see table 1). In the design of the generator with a free piston (rotor) and cylinder (housing), a significant increase in the compression ratio up to 50 is possible, which provides an increase in efficiency up to 50 and higher, the ability to work on mixtures of very poor composition, providing improved environmental characteristics of the EHF.

The calculation results confirm that the electrical efficiency for the declared options for hot water is from 50% or more.

Input parameters for the calculation: linear generator with an internal arrangement of magnets 400 mm long, 80 mm in diameter, piston length 120 mm. The masses of the piston and cylinder are the same 3 kg, the combustion of a methane-air mixture with an excess air coefficient of 1.5, a compression ratio of 20-40, a compression pressure of 60-80 atm.

In contrast to the combustion process of the mixture in the cylinder of a conventional ICE, where uneven mixing of fuel with air leads to incomplete combustion of the fuel and, consequently, to a deterioration in the economic and environmental characteristics of the engine, a high design with a free piston (rotor) and cylinder (housing) is possible completeness of chemical transformation over the entire volume of the compressible gas at a high degree of compression without fear of collision of free elements, since the process rate weakly depends on the local liva. In mixtures not capable of self-combustion and for mixtures with a large excess of oxidizing agent, the requirements for purging the cylinder before filling it with a fresh portion of the mixture are reduced. This simplifies the design of the device, makes efficient use of the push-pull cycle of the device, expands the class of possible fuels. Due to a decrease in the operating temperature, heat losses are reduced, and the increased working stroke of the free piston as compared with a conventional ICE allows to reduce the temperature of the “refrigerator” and thereby increase the thermodynamic efficiency of the device. An important advantage of the device is the ability to control its power in a wider range of changes in the composition of the mixture. With the connected operation of several devices, there is no need to synchronize the movement of moving elements, if the system is perfectly balanced.

Using the invention will make it possible to convert the chemical energy of fuel into electrical energy while reducing harmful components in the products of chemical conversion, to increase the completeness of chemical conversion, to expand the class of fuels used and by reducing heat loss, increasing thermodynamic and electrical efficiency and simplifying the design and balanced operation of the device to increase its efficiency .

List of documents

1. Gas piston power plant. RF patent No. 2411378, F02B 63/04.

2. Vasiliev Yu.N. and other free-piston engines-compressors for the gas industry. J. "Gas industry", No. 2, 1992,

3. Blarigan P.V. 2001. Advanced internal combustion electrical generator // Proceedings of the 2001 DOE Hydrogen Program Review. 23 p.

4. Dukhanin V.I., Ketsaris A.A. Analysis of the design of the automobile generator of reciprocating motion // News of MSTU "MAMI", 2012, No. 2 (14). S. 97-104.

5. Patent US 6541875 B1, May 17, 2000.

6. RF patent 2237817, 01/09/2003.

7. RF patent 2138656, 06/26/1998.

Claims (11)

1. A device for converting chemical energy of a fuel-air mixture into electric, including a cylinder, a free piston, made with the possibility of translational motion in a cylinder equipped with inlet and exhaust valves, an electromagnetic system, characterized in that the cylinder is made free, the electromagnetic system contains magnets, electrical windings and magnetic circuit, while magnets or magnetic circuit are located on a free piston, electrical windings with magnetic circuit or magnets with electrical windings are installed a free cylinder. 2. A device for converting chemical energy of a fuel-air mixture into electric, including a cylinder, a free piston, made with the possibility of translational motion in a cylinder equipped with inlet and outlet valves, an electromagnetic system, characterized in that the cylinder is made free, the electromagnetic system contains magnets, electrical windings and a magnetic circuit, while the magnets or magnetic circuit are mounted on a free cylinder, and electrical windings with a magnetic circuit or magnets with electrical windings are placed in an annular system around a free cylinder. 3. A device for converting chemical energy of a fuel-air mixture into electrical energy, including a housing, a rotor configured to oscillate-rotate in a housing equipped with inlet and outlet valves, an electromagnetic system, characterized in that the rotor and the housing are made free, the free rotor is connected to the ring system, and the ring system and the free case are equipped with an electromagnetic system. 4. The device according to claim 3, characterized in that the electromagnetic system contains magnets, electrical windings and a magnetic circuit. 5. The device according to claim 3, characterized in that magnets or magnetic core are mounted on a free housing. 6. The device according to claim 3, characterized in that electrical windings with a magnetic circuit or magnets with electrical windings are placed in a ring system around a free housing.

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