RU171447U1 - Structural diagram of an automotive thermoelectric generator with a variable geometry heat exchanger - Google Patents

Abstract

The utility model relates to the field of recovery of thermal energy of exhaust gases (OG) of an internal combustion engine (ICE) and direct conversion of thermal energy into electrical energy and can be used to provide electrical energy to the nodes of the power supply system of a vehicle with internal combustion engine. The technical result is an increase in the efficiency of the thermoelectric generator (TEG) by ensuring uniform temperature distribution along the hot side of the thermocouples along the length of the TEG heat exchanger and maintaining the temperature when changing the operating mode of the internal combustion engine. SUBSTANCE: automobile TEG with a hot heat exchanger of variable geometry with a cross section in the form of a polyhedron in the exhaust system of exhaust gases of an internal combustion engine, in which at least one movable rotary fin is mounted on the flow part of the hot heat exchanger, at least on one face of the hot heat exchanger, fixed on a rotating axis perpendicular to the plane of the face of the hot heat exchanger and passing through the hole in it. The angular position of the rotary rib is controlled through the outer end of the axis. 2 ill.

Description

Technical field

The utility model relates to the field of recovery of thermal energy of exhaust gases (OG) of an internal combustion engine (ICE) and direct conversion of thermal energy into electrical energy and can be used to provide electrical energy to the nodes of the power supply system of a vehicle with internal combustion engine.

State of the art

Known design (patent application US US 20130340801 Thermoelectric Power Generation System Using Gradient Heat Exchanger (IPC H01L 35/30, published 2013-12-26)) thermoelectric generator (TEG) with a gradient heat exchanger.

The disadvantage of this design is the large geometric dimensions and operating efficiency only in a narrow range of gas flow rates.

It is also known a device with a heat exchanger for a car TEG (RF patent 2566209, IPC F01N 3/04, F01N 5/02, Published: 10/20/2015), which uses mainly ring thermoelectric batteries located around the tubes of the heat exchanger, which has a bypass and various designs for additional swirling flow and intensification of heat transfer.

The disadvantage of this design is the lack of means to maintain equal temperature along the length of the TEG and with the steady-state mode of operation of the internal combustion engine and, especially, with changing operating modes of the internal combustion engine.

Also known is the design of a TEG for a car with an internal combustion engine (US patent US 5625245 Thermoelectric generator for motor vehicle (IPC H01L 35/00; H02N 3/00, published: 1997-04-29)), selected as a prototype consisting primarily of a hot heat exchanger an octagonal shape with a cylindrical body in the form of a pipe, which is a support for the springs used to clamp the thermocouples.

The disadvantage of this design is also the difficulty of ensuring uniform temperature on the hot side of thermoelectric batteries, as well as the inability to adapt to the changing operating mode of the internal combustion engine of a car.

Utility Model Disclosure

The technical result of the proposed utility model is to increase the efficiency of the TEG for ICE vehicles by ensuring uniform temperature distribution along the hot side of the thermocouples along the length of the TEG heat exchanger and maintaining the temperature when changing the mode of operation of the ICE.

The technical result is achieved by the fact that a structural scheme of an automobile TEG with a hot heat exchanger of variable geometry with a cross section in the form of a polyhedron in the exhaust system of the engine exhaust gas is proposed, in which at least one face of the hot heat exchanger has at least one face of the hot heat exchanger installed , one movable rotary rib mounted on a rotating axis perpendicular to the plane of the face of the hot heat exchanger and passing through the hole in it, and control sexually-position of the rotary fin through the outer end of the shaft.

List of figures

In FIG. 1 shows a side section of a TEG showing the design of the rotary ribs.

In FIG. Figure 2 shows a general view of a TEG in isometric view with a partial section to show the possible position of the turning ribs.

Utility Model Implementation

The TEG shown in FIG. 1, 2, consists of a hot heat exchanger 1 with a displacer 2, thermoelectric modules 3, on top of which there are cold heat exchangers 4. Inside the hot heat exchanger of variable geometry with a section in the form of a convex polyhedron, there are rotary fins 5 (individually or in rows from the beginning to the end of the TEG ) mounted on the rotating axles 6 passing through the holes in the hot heat exchanger.

A feature of ICE vehicles is the need to work in a wide range of revolutions and loads. The consequence is variable over a wide range of temperature and exhaust gas flow. The TEG heat exchanger must provide a sufficient temperature on the hot side of the TEG, as well as the uniformity of temperatures along the length of the TEG. Under stationary conditions of ICE operation, these requirements are ensured by the use of heat exchangers with fins variable in length. The disadvantage of such structures is the inefficiency of their work with a variable mode of internal combustion engine operation.

For ICE vehicles with a variable operating mode, an adaptive heat exchanger design is proposed, which ensures the maintenance of a sufficient temperature and uniformity of temperature along the TEG along with changing temperature and exhaust gas flow.

The proposed heat exchanger has a movable rotary fins, each of which in its center is mounted on a rotating axis. The axis passes through an opening in the face of the heat exchanger. The rotation of the ribs is carried out at the outer end of the axis. If the ribs are located in the same row, the outer ends of their axes can be mechanically aligned, because, due to the symmetry of the structure, the ribs should be rotated at the same angles.

The rotation on the axis of the ribs can be transmitted due to gear engagement, for this purpose a gear wheel can be installed at the end of the axis, which is meshed with the gear ring. Since there is no need to complete a full rotation of the axis of the rib, other simple and reliable gears can be used instead of gearing. Also, in the alternative case, each axis can have an individual drive, for example, using electric motors.

In the mode when all the turning ribs are parallel to the flow of exhaust gases, a minimum gas-dynamic resistance is created, but the heat transfer from the exhaust gases is also minimal, which leads to a decrease in the wall temperature. An increase in the angle between the direction of the rib and the longitudinal axis of the TEG leads to an increase in resistance, an increase in turbulence, a swirl of the flow, and, as a result, an increase in heat transfer from the exhaust gases to the wall of the hot heat exchanger. The greater the angle of rotation of the ribs, the more intense the heat transfer. Thus, increasing the wall temperature of the hot heat exchanger is possible by increasing the angle of rotation of the ribs, and maintaining uniformity of temperature along the length of the TEG is possible by increasing the angle of rotation of the rows of ribs from the beginning to the end of the TEG. Adjustment of the angle of the rib on the outside of the TEG can be carried out during the operation of the TEG. Due to this, the configuration of the flow part of the generator can adapt to the changing conditions of the flow of exhaust gases in variable modes of internal combustion engine operation.

The mechanism responsible for the rotation of the ribs can provide sufficient speed and positioning accuracy and can respond to changes in the internal combustion engine operation mode. When the engine is idling or at low load, the ribs can be rotated at large angles, increasing from the beginning to the end of the TEG. Due to this, a sufficiently high temperature on the hot side of the heat exchanger and temperature uniformity along the face can be maintained. With an increase in engine load and an increase in the flow rate and temperature of the exhaust gases, the angle of rotation of the ribs can be reduced to reduce the created gas-dynamic resistance. The difference in the angles of rotation of the first and last rows of rotary ribs can also be reduced, since the cooling of the exhaust gases when passing through the TEG decreases with an increase in the heat flux. With a further increase in the load on the internal combustion engine and a subsequent increase in temperature and exhaust gas flow, the angle of rotation of the ribs can be reduced to zero, reducing resistance, reducing heat transfer and, thus, preventing overheating of thermoelectric batteries.

A possible angular position of the ribs, providing temperature equalization and increased heat transfer, is shown in FIG. 2.

The proposed design of the TEG was developed during the implementation of applied scientific research (PNI) under the Agreement on the provision of subsidies No. 14.577.21.0113 between the Ministry of Education and Science of the Russian Federation and MSTU. N.E. Bauman.

Claims (1)

A structural diagram of an automobile thermoelectric generator with a hot heat exchanger of variable geometry with a cross section in the form of a polyhedron in the exhaust system of the exhaust gases of an internal combustion engine, characterized in that at least one face of the hot heat exchanger has at least one facet installed on the hot heat exchanger a movable rotary rib mounted on a rotating axis perpendicular to the plane of the face of the hot heat exchanger and passing through the hole in it, with the ability to control the angular position of the rotary rib through the outer end of the axis.

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