A heat storage type exhaust pipe and truck fuel tank insulation system based on radial heat pipe and its control strategy

Abstract

The present invention provides a heat storage type exhaust pipe and truck fuel tank insulation system based on radial heat pipe and its control strategy, including a curved heat pipe, a working section and a heat storage unit, wherein the curved heat pipe includes a straight section and curved sections at both ends of the straight section, wherein the straight section is located in the working section, and one end of the curved section extends out of the working section; the curved heat pipe is a double-layer heat pipe, wherein the double-layer heat pipe includes a radial heat pipe outer pipe and a radial heat pipe inner pipe, wherein the radial heat pipe inner pipe is connected to circulating water, and the closed cavity between the radial heat pipe outer pipe and the radial heat pipe inner pipe is filled with working fluid; the heat storage unit includes a heat exchange channel, a heat storage unit cavity and a phase-change heat storage medium, wherein the heat storage unit cavity is provided outside the working section, wherein the phase-change heat storage medium is filled in the heat storage unit cavity, and a heat exchange channel is provided outside the heat storage unit cavity, wherein the heat exchange channel is connected to circulating water. The present invention can utilize the waste heat of flue gas.

Description

Technical Field

[0001] The invention relates to the field of vehicle preheating or heat exchange, and in particular to a heat storage type exhaust pipe and truck fuel tank insulation system based on a radial heat pipe and a control strategy thereof. Background Art

[0002] In some cold regions, the diesel in the fuel tank of a large truck will produce a waxy solid due to the low temperature, which is not conducive to the diesel passing through the filter and entering the diesel engine for combustion. The average temperature in Northeast my country in winter is generally -25℃. Taking No. 0 diesel as an example, when it is below 4℃, it will solidify and produce a layer of waxy substances. One of the measures currently used in the market is to use a double-chamber fuel tank, that is, the fuel uses low-grade diesel in the first ten minutes of vehicle startup, and burns high-grade diesel after the vehicle has been running for a period of time. The other is fuel heating technology to keep it above the freezing point. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a heat storage type exhaust pipe and truck fuel tank insulation system based on radial heat pipes and a control strategy thereof, which has a good heat exchange effect while meeting the requirements of compact structure. By adding outer tube fins to enhance the convective heat exchange on the flue gas side, the flue gas continuously flows through the working section, and the curved heat pipes in the working section transfer the waste heat of the flue gas radially to the inner tube.

[0004] The present invention achieves the above technical objectives through the following technical means.

[0005] A heat pipe-based heat storage type smoke exhaust pipe, comprising a bent heat pipe, a working section and a heat storage unit

[0006] The two ends of the working section are respectively provided with a smoke inlet and a smoke outlet, the curved heat pipe comprises a straight section and curved sections located at both ends of the straight section, the straight section is located in the working section, and one end of the curved section extends out of the working section;

[0007] The curved heat pipe is a double-layer heat pipe, comprising a radial heat pipe outer pipe and a radial heat pipe inner pipe, the radial heat pipe inner pipe is connected to circulating water, and a closed cavity between the radial heat pipe outer pipe and the radial heat pipe inner pipe is filled with a working fluid;

[0008] The heat storage unit includes a heat exchange channel, a heat storage unit cavity and a phase-change heat storage medium. The heat storage unit cavity is provided outside the working section, and the heat storage unit cavity is filled with phase-change heat storage medium. A heat exchange channel is provided outside the heat storage unit cavity, and the heat exchange channel is connected to circulating water.

[0009] Furthermore, fins are arranged at intervals on the outer wall of the outer tube of the radial heat pipe, and the fins are perpendicular to the flow direction of the flue gas.

[0010] Furthermore, the outer wall surface of the inner tube of the radial heat pipe is provided with a plurality of spiral grooves for condensing and refluxing the working fluid.

[0011] Furthermore, the working fluid is Thermal Conductivity A.

[0012] Furthermore, the flow direction of the flue gas in the working section is opposite to the flow direction of the circulating water in the radial heat pipe.

[0013] Furthermore, the phase change heat storage medium is KOH.

[0014] Furthermore, a plurality of curved heat pipes are evenly distributed in the working section, and a plurality of heat exchange channels are evenly distributed outside the cavity of the heat storage unit.

[0015] A truck fuel tank insulation system comprises the heat pipe-based heat storage type smoke exhaust pipe and a fuel tank heat exchanger. The fuel tank is provided with a fuel tank heat exchanger. The heat exchange channel and the two ends of the radial heat pipe inner tube are respectively connected to the circulating water of the fuel tank heat exchanger through a variable three-way valve.

[0016] Further, it also includes a control system, a temperature transmitter and an electric heating device;

[0017] The temperature transmitter is used to measure the oil temperature in the fuel tank; an electric heating device is provided in the fuel tank, and the control system selectively controls the variable three-way valve to connect the circulating water of the heat exchanger in the fuel tank with the heat exchange channel or the inner tube of the radial heat pipe, or selectively controls the electric heating device to heat the fuel tank according to the state of the truck and the oil temperature in the fuel tank.

[0018] A control strategy for a truck fuel tank insulation system includes the following steps:

[0019] When the control system determines that the vehicle is in driving mode according to the vehicle condition, the control system controls the variable three-way valve to connect the circulating water of the heat exchanger in the fuel tank with the inner tube of the radial heat pipe, so that the circulating water exchanges heat with the flue gas and then exchanges heat with the medium in the fuel tank; the control system controls the flow rate of the circulating water according to the temperature detected by the temperature transmitter, so that the temperature of the medium in the fuel tank is maintained at a first set value;

[0020] When the control system determines that the vehicle is in parking mode according to the vehicle condition, the control system controls the variable three-way valve to connect the circulating water of the heat exchanger in the fuel tank with the heat exchange channel, so that the circulating water exchanges heat with the phase-change heat storage medium and then exchanges heat with the medium in the fuel tank; the control system controls the flow rate of the circulating water according to the temperature detected by the temperature transmitter, so that the temperature of the medium in the fuel tank is maintained at a second set value; the second set value is lower than the first set value;

[0021] When the control system determines that the vehicle is started according to the vehicle condition, and when the temperature of the medium in the fuel tank detected by the temperature transmitter is lower than a second set value, the control system controls the electric heating device to heat the medium in the fuel tank.

[0022] The beneficial effects of the present invention are:

[0023] 1. The invention discloses a heat storage type exhaust pipe based on a radial heat pipe, wherein the curved heat pipe includes a straight section and curved sections at both ends of the straight section, wherein the straight section is located in the working section, and one end of the curved section extends out of the working section, which is conducive to achieving a compact structure and good heat exchange effect. The fins are installed on the outer tube of the radial heat pipe to strengthen the convective heat exchange on the flue gas side, and the flue gas continuously flows through the working section, and the curved heat pipe in the working section transfers the residual heat of the flue gas radially to the inner tube.

[0024] 2. The radial heat pipe-based heat storage type smoke exhaust pipe described in the present invention has a heat storage unit cavity outside the working section, and the heat storage unit cavity is filled with a phase-change heat storage medium, which stores part of the waste heat of the flue gas in the phase-change heat storage medium, thereby improving the efficiency of flue gas utilization.

[0025] 3. The truck fuel tank insulation system of the present invention can realize the alternating recycling of heat stored in the heat storage medium and waste heat in the flue gas through a variable three-way valve.

[0026] 5. The control strategy of the truck fuel tank insulation system described in the present invention adopts different fuel tank insulation methods according to the actual operation of the vehicle. The present invention adopts a variable three-way valve and a pump controlled by a variable frequency motor. The temperature transmitter is set on the fuel tank to collect the fuel tank temperature and transmit it to the control system. The control system switches different working modes according to the different operation conditions of the vehicle, and stabilizes the fuel tank temperature by controlling the regulating pump to adjust the flow rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, it is obvious that other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a three-dimensional diagram of the heat storage type smoke exhaust pipe based on the radial heat pipe described in the present invention.

[0029] Figure 2 The left side view of the heat storage type smoke exhaust pipe based on the radial heat pipe of the present invention

[0030] Figure 3 It is a half-section view of the heat storage type smoke exhaust pipe based on the radial heat pipe according to the present invention.

[0031] Figure 4 This is a schematic diagram of the truck fuel tank insulation system of the present invention.

[0032] In the figure:

[0033] 1-smoke inlet; 2-working section; 3-bent heat pipe; 4-heat storage unit; 5-smoke outlet; 8-radial heat pipe outer tube; 10-radial heat pipe outer wall; 11-heat storage unit water outlet; 12-radial heat pipe inner tube; 13-working fluid; 14-spiral groove; 15-fin; 16-heat exchange channel; 17-heat storage unit cavity; 18-phase change heat storage medium; 19-heat storage unit water inlet; 22-engine; 24-temperature transmitter; 25-oil tank; 26-heat exchanger; 27-variable three-way valve; 28-regulating pump; 30-battery; 31-electric heating device; 32-controllable flow valve. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] like Figure 1 and Figure 3 As shown, the heat pipe-based heat storage type smoke exhaust pipe of the present invention comprises a bent heat pipe 3, a working section 2 and a heat storage unit 4.

[0039] The two ends of the working section 2 are respectively provided with a smoke inlet 1 and a smoke outlet 5. The curved heat pipe 3 includes a straight section and a 90° curved section located at both ends of the straight section. The straight section is located in the working section 2, and one end of the curved section extends out of the working section 2, so that the curved section can be fully extended to the outside of the working section 2. The straight section is axially parallel to the working section 2. The curved heat pipe 3 is a double-layer heat pipe, which includes a radial heat pipe outer tube 8 and a radial heat pipe inner tube 12. The radial heat pipe inner tube 12 is concentrically arranged inside the radial heat pipe outer tube 8. The radial heat pipe inner tube 12 is connected to the circulating water, and the closed cavity between the radial heat pipe outer tube 8 and the radial heat pipe inner tube 12 is filled with a working fluid 13.

[0040] The heat storage unit 4 includes a heat exchange channel 16, a heat storage unit cavity 17 and a phase-change heat storage medium 18. The heat storage unit cavity 17 is provided outside the working section 2. The heat storage unit cavity 17 is filled with the phase-change heat storage medium 18. The heat exchange channel 16 is provided outside the heat storage unit cavity 17. The heat exchange channel 16 is connected to the circulating water. One end of the heat exchange channel 16 is the heat storage unit water inlet 19, and the other end of the heat exchange channel 16 is the heat storage unit water outlet 11. Figure 2 As shown, three curved heat pipes 3 are distributed in the working section 2. The heat storage unit 4 is arranged concentrically with the working section 2, and three heat exchange channels 16 are evenly distributed in the shell of the heat storage unit outside the working section 2, which effectively and evenly distributes the load and avoids the loosening of the exhaust pipe due to uneven center of gravity. The phase change heat storage medium 18 is KOH.

[0041] The outer wall of the radial heat pipe outer tube 8 is provided with fins 15 at intervals, and the fins 15 are perpendicular to the flue gas flow direction, so that the fins 15 have a higher heat transfer coefficient and service life. The fins 15 distributed at intervals can effectively reduce the flow resistance while strengthening the heat transfer effect outside the radial heat pipe outer tube. The working fluid 13 is thermal conductivity A, and its main function is to perform phase change heat transfer. Thermal conductivity A has a lower vapor pressure, so it is safer to use in the field of automobile exhaust waste heat utilization. The outer wall surface of the radial heat pipe inner tube 12 is provided with a plurality of spiral grooves 14, which are used to condense and reflux the working fluid 13.

[0042] The flow direction of the flue gas in the working section 2 is opposite to the flow direction of the circulating water in the radial heat pipe inner tube 12. Figure 3As shown, the flue gas enters the working section 2 from the left, and the circulating water enters from the right, countercurrent to the flue gas, with a higher average temperature difference, which can achieve a better heat exchange effect. The material of the sleeve-type heat storage element must ensure that it is not easily corroded by the salt phase change material in the molten state. It is made of carbon steel, and the surface is treated with hot zinc coating to effectively avoid molten salt corrosion. The heat storage element is installed with a positioning groove between the outer tube wall of the working section 2 to facilitate the replacement of the phase change material in the heat storage element.

[0043] In the heat transfer process of radial heat pipe, there are mainly heat transfer resistance of flue gas outside the outer tube, heat conduction resistance of outer tube wall, heat transfer resistance of boiling heat transfer of working medium inside the tube, heat transfer resistance of steam convection heat transfer of working medium inside the tube, heat transfer resistance of condensation heat transfer of inner tube wall, heat conduction resistance of inner tube wall and heat transfer resistance of circulating water convection heat transfer of inner tube. In order to ensure the good working performance of radial heat pipe, the wall thickness of radial heat pipe should be able to withstand the working pressure environment, and the wall thickness of radial heat pipe is 2mm.

[0044] like Figure 4 As shown, the truck fuel tank insulation system described in the present invention includes a heat pipe-based heat storage type smoke exhaust pipe, an engine 22, a temperature transmitter 24, a fuel tank 25, a heat exchanger 26, a variable three-way valve 27, a regulating pump 28, a battery 30, an electric heating device 31, a controllable flow valve 32 and a control system, wherein the engine 22 is connected to the fuel tank 25, and an internal heat exchanger 26 is provided in the fuel tank 25, and a circulating water outlet of the internal heat exchanger 26 is connected to the regulating pump 28, and the regulating pump 28 is connected to the heat exchange channel 16 or the radial heat pipe inner tube 12 through the variable three-way valve 27, and a controllable flow valve 32 is installed at the circulating water inlet of the internal heat exchanger 26, and the controllable flow valve 32 is connected to the heat exchange channel 16 or the radial heat pipe inner tube 12 through the variable three-way valve 27. A temperature transmitter 24 is installed in the oil tank 25 for detecting the oil temperature. An electric heating device 31 is installed in the oil tank 25 and the electric heating device 31 is operated by a battery 30 .

[0045] The control system selectively controls the variable three-way valve 27 to connect the circulating water of the heat exchanger 26 in the tank with the heat exchange channel 16 or the inner tube 12 of the radial heat pipe, or selectively controls the electric heating device 31 to heat the tank 25 according to the state of the truck and the oil temperature in the tank 25 .

[0046] The control strategy of the truck fuel tank insulation system of the present invention comprises the following steps:

[0047] When the control system determines that the vehicle is in driving mode according to the vehicle condition, the control system controls the variable three-way valve 27 to connect the circulating water of the heat exchanger 26 in the fuel tank with the inner tube 12 of the radial heat pipe, and the waste heat of the flue gas is transferred to the internal working fluid through the intermittent fins on the outer tube wall of the radial heat pipe. The internal working fluid undergoes a phase change to transfer the heat to the inner tube wall, and then transfers the heat to the circulating water of the inner tube through the heat conduction of the inner tube wall. During the whole process, the circulating water exchanges heat with the flue gas, and the circulating water is collected by the controllable flow valve 32 and enters the heat exchanger 26 in the fuel tank 25 to exchange heat with the diesel. The control system can control the opening of the flow valve 32 and the speed of the regulating pump 28 according to the temperature detected by the temperature transmitter 24, thereby controlling the flow rate of the circulating water, so that the medium temperature in the fuel tank is maintained at 25 degrees;

[0048] When the control system determines that the vehicle is in parking mode according to the vehicle condition, the control system controls the variable three-way valve 27 to connect the circulating water of the heat exchanger 26 in the fuel tank with the heat exchange channel 16, and the circulating water exchanges heat with the phase-change heat storage medium 18 and then exchanges heat with the medium in the fuel tank; the control system can control the opening of the flow valve 32 and the speed of the regulating pump 28 according to the temperature control detected by the temperature transmitter 24, thereby controlling the flow rate of the circulating water, so that the temperature of the medium in the fuel tank is maintained at 5 degrees;

[0049] The control system determines that the vehicle is starting according to the vehicle condition. When the temperature of the medium in the fuel tank detected by the temperature transmitter 24 is lower than 5 degrees, the control system controls the electric heating device 31 to heat the medium in the fuel tank so that the diesel wax melts to achieve the purpose of rapid starting.

[0050] When a truck is driving, the external fuel tank is equivalent to being longitudinally passed over the outer wall of the fuel tank by the external environment. The main forms of heat loss are convection heat exchange between the external air and the fuel tank and the heat load when the fuel tank is heated. Collecting and storing the waste heat from the truck exhaust can be used in two aspects. One is to keep the fuel tank warm when the truck is parked for a short time; the other is to release heat in a short time to heat the fuel tank when starting after a long parking period to ensure that the oil temperature reaches above the freezing point. The heat exchange rate effect can be achieved by controlling the mass flow rate of the heat exchange fluid.

[0051] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0052] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A truck fuel tank insulation system, characterized in that: It includes a heat pipe-based heat storage type exhaust pipe and a heat exchanger (26) in the oil tank, The heat pipe-based heat storage type smoke exhaust pipe comprises a bent heat pipe (3), a working section (2) and a heat storage unit (4); the working section (2) is provided with a smoke inlet (1) and a smoke outlet (5) at both ends thereof; the bent heat pipe (3) comprises a straight section and bent sections located at both ends of the straight section; the straight section is located in the working section (2), and one end of the bent section extends out of the working section (2); the bent heat pipe (3) is a double-layer heat pipe, and the double-layer heat pipe comprises a radial heat pipe outer tube (8) and a radial heat pipe inner tube (12); the radial heat pipe inner tube (12) is connected to circulating water, and the closed cavity between the radial heat pipe outer tube (8) and the radial heat pipe inner tube (12) is filled with working fluid (13); the heat storage unit (4) comprises a heat exchange channel (16), a heat storage unit cavity (17) and a phase-change heat storage medium (18); the heat storage unit cavity (17) is provided outside the working section (2), the heat storage unit cavity (17) is filled with phase-change heat storage medium (18), and a heat exchange channel (16) is provided outside the heat storage unit cavity (17), and the heat exchange channel (16) is connected to circulating water; An internal oil tank heat exchanger (26) is provided in the oil tank (25); the heat exchange channel (16) and both ends of the radial heat pipe inner tube (12) are respectively connected to the circulating water of the internal oil tank heat exchanger (26) via a variable three-way valve (27); fins (15) are provided at intervals on the outer wall of the radial heat pipe outer tube (8); the fins (15) are perpendicular to the direction of flue gas flow.

2. The truck fuel tank insulation system according to claim 1, characterized in that: The outer wall surface of the radial heat pipe inner tube (12) is provided with a plurality of spiral grooves (14) for condensing and refluxing the working fluid (13).

3. The truck tank insulation system according to claim 1, characterized in that: The working fluid (13) is thermal conductivity A.

4. The truck fuel tank insulation system according to claim 1, characterized in that: The flow direction of the flue gas in the working section (2) is opposite to the flow direction of the circulating water in the inner tube (12) of the radial heat pipe.

5. The truck fuel tank insulation system according to claim 1, characterized in that: The phase-change heat storage medium (18) is KOH.

6. The truck fuel tank insulation system according to claim 1, characterized in that: A plurality of curved heat pipes (3) are evenly distributed in the working section (2), and a plurality of heat exchange channels (16) are evenly distributed outside the heat storage unit cavity (17).

7. The truck fuel tank insulation system according to any one of claims 1 to 6, characterized in that: It also includes a control system, a temperature transmitter (24) and an electric heating device (31); The temperature transmitter (24) is used to measure the oil temperature in the oil tank (25); an electric heating device (31) is provided in the oil tank (25); and the control system selectively controls the variable three-way valve (27) to connect the circulating water of the heat exchanger (26) in the oil tank with the heat exchange channel (16) or the inner tube (12) of the radial heat pipe, or selectively controls the electric heating device (31) to heat the oil tank (25), according to the state of the truck and the oil temperature in the oil tank (25).

8. A truck tank insulation system control strategy according to claim 7, characterized in that: The steps include: When the control system determines that the vehicle is in driving mode according to the vehicle condition, the control system controls the variable three-way valve (27) to connect the circulating water of the heat exchanger (26) in the fuel tank to the inner tube (12) of the radial heat pipe, so that the circulating water exchanges heat with the flue gas and then exchanges heat with the medium in the fuel tank; the control system controls the flow rate of the circulating water according to the temperature detected by the temperature transmitter (24), so that the temperature of the medium in the fuel tank is maintained at a first set value; When the control system determines that the vehicle is in parking mode according to the vehicle condition, the control system controls the variable three-way valve (27) to connect the circulating water of the heat exchanger (26) in the fuel tank to the heat exchange channel (16), so that the circulating water exchanges heat with the phase-change heat storage medium (18) and then exchanges heat with the medium in the fuel tank; the control system controls the flow rate of the circulating water according to the temperature detected by the temperature transmitter (24), so that the temperature of the medium in the fuel tank is maintained at a second set value; the second set value is lower than the first set value; The control system determines that the vehicle is started according to the vehicle condition, and when the temperature of the medium in the oil tank detected by the temperature transmitter (24) is lower than a second set value, the control system controls the electric heating device (31) to heat the medium in the oil tank.

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