A power generation system using waste heat from automobile exhaust

Abstract

This utility model belongs to the field of energy recovery and utilization technology, specifically relating to a power generation system utilizing the waste heat of automotive exhaust gas. It includes a gas flow chamber, a flow-dispersing component, and a power generation component. The gas flow chamber has a gas inlet and a gas outlet, both connected to the front and rear ends of an exhaust pipe via connecting flanges and flange gaskets, respectively. The flow-dispersing component is disposed inside the gas flow chamber and includes multiple flow-dispersing plates. These plates are linearly distributed in multiple rows along the direction from the gas inlet to the gas outlet, and are obliquely fixed to the side wall of the gas flow chamber. The power generation component includes a thermoelectric generator and a cooler. The high-temperature side of the thermoelectric generator is fitted against the outer wall of the gas flow chamber, while the low-temperature side is connected to the cooler. The cooler regulates the temperature of the low-temperature side of the thermoelectric generator to stabilize the temperature difference between the high-temperature and low-temperature sides. This effectively improves the heat exchange rate of the exhaust gas and enhances the efficiency of thermoelectric power generation.

Description

Technical Field

[0001] This utility model belongs to the field of energy recovery and utilization technology, specifically relating to a power generation system based on the residual heat of automobile exhaust. Background Technology

[0002] In recent years, semiconductor thermoelectric power generation technology has emerged as a key technology in the field of energy recovery, becoming one of the crucial technologies for energy conservation and emission reduction strategies. This technology is based on the Seebeck effect, where a potential difference is created between two different semiconductor materials under a temperature gradient, enabling the direct conversion of heat energy into electrical energy. It boasts significant advantages such as compact structure, zero noise, no wear from moving parts, and zero emissions, demonstrating immense value, especially in the field of industrial waste heat recovery. The thermoelectric power generation module, by coupling exhaust gas waste heat with environmental cooling, can recover energy emitted as waste heat after fuel combustion, thereby improving energy utilization efficiency.

[0003] As an important technological carrier for energy conservation and emission reduction strategies, tail-end thermoelectric power generation systems have made significant progress in recent years in optimizing heat-to-electric conversion efficiency. For example, Shen Haiqing et al. used Fluent software to construct a multi-physics coupling model of a thermoelectric power generation module, and installed heat exchange fins, which improved the heat transfer coefficient by about 30%. Hu Weiping et al. used Fluent software to explore the influence of different fin structures and sizes on the heat transfer performance of pipes, and analyzed the impact of fin structure changes on the heat transfer coefficient from a mechanistic perspective. Ji Xiaofeng et al. developed a grid-like vented pipe device, which successfully improved energy conversion efficiency through multi-channel collaborative design. Yu Sanchuan et al. studied the flow and heat transfer characteristics of fluids inside an annular corrugated spiral tube heat exchanger. Although the flow resistance loss of the annular corrugated spiral tube increased slightly, it had significant energy-saving and emission-reduction benefits. Du Zhuocheng et al. added fins to a cylindrical heat exchanger and changed the fin geometry parameters, observing the changes in the heat exchanger's heat transfer performance.

[0004] Existing exhaust gas thermal energy conversion systems have limited heat exchange capacity for exhaust gases, making it difficult to fully improve their heat exchange efficiency. For example, existing exhaust gas thermal energy conversion systems mainly use natural air cooling to recover energy from exhaust gases for thermal energy generation. However, the heat exchange rate for exhaust gases is low, especially when vehicles are traveling at high speeds, as the contact time between natural air and exhaust gases is very short, resulting in a conversion efficiency of only 2.5% to 3.2%. This leads to low utilization of exhaust gas thermal energy and relatively low power generation efficiency. In view of these problems, a power generation structure design based on the waste heat of vehicle exhaust gases is proposed. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the purpose of this utility model is to provide a power generation system using the waste heat of automobile exhaust, which can effectively improve the heat exchange rate of exhaust gas and greatly improve the efficiency of exhaust gas power generation.

[0006] The technical solution of this utility model is:

[0007] A power generation system using waste heat from automobile exhaust, comprising:

[0008] A gas flow chamber for installation between a particulate filter and a muffler in an exhaust pipe, the gas flow chamber having a gas inlet and a gas outlet disposed opposite to each other;

[0009] A flow-disrupting assembly is disposed inside the gas flow chamber and includes multiple flow-disrupting plates. The multiple flow-disrupting plates are linearly distributed in multiple rows in the gas flow chamber along the direction from the gas inlet to the gas outlet. The flow-disrupting plates are obliquely fixed on the side wall of the gas flow chamber. The flow-disrupting plates are used to guide the flow path of the airflow entering the gas flow chamber so as to achieve cyclic contact between the airflow and the wall of the gas flow chamber.

[0010] The power generation component includes a thermoelectric generator and a cooler. The high-temperature side of the thermoelectric generator is attached to the outer wall of the gas flow chamber, and the low-temperature side is connected to the cooler. The cooler is used to regulate the temperature of the low-temperature side of the thermoelectric generator to achieve a stable temperature difference between the high-temperature and low-temperature sides of the thermoelectric generator. The thermoelectric generator is used to connect to vehicle electrical appliances or vehicle batteries.

[0011] Preferably, the gas flow chamber has a rectangular cross-section.

[0012] Preferably, there are multiple thermoelectric generators, and the multiple thermoelectric generators are evenly distributed on each outer wall of the gas flow chamber.

[0013] Preferably, the cooler includes a split-type sleeve that wraps around the outside of the gas flow chamber. The inner wall of the sleeve is in contact with the low-temperature side of the thermoelectric generator, and heat dissipation fins are evenly distributed on the outer wall of the sleeve.

[0014] Preferably, the inner sidewall of the sleeve is further provided with a serpentine water-cooling pipe, which is filled with coolant. One end of the water-cooling pipe is connected to the outlet of the water pump, and the other end is connected to the inlet of the water pump. A radiator is also connected in series on the water-cooling pipe.

[0015] Preferably, a VC heat exchanger is provided between the thermoelectric generator and the side wall of the gas flow chamber.

[0016] Preferably, the tilt angle of the spoiler is 30°~60°.

[0017] Preferably, the spoilers in each column are arranged at equal intervals, and the distance between two adjacent spoilers is 20mm to 70mm.

[0018] Compared with the prior art, the power generation system based on the waste heat of automobile exhaust of this utility model has the following beneficial effects:

[0019] This device uses a gas flow chamber as a carrier. By arranging multiple rows of turbulence-inducing vanes at an angle on the sidewall of the gas flow chamber, the residence time of the exhaust gas can be extended and the airflow turbulence can be increased. This allows heat to be fully transferred to the high-temperature side of the thermoelectric generator, ensuring that the high-temperature exhaust gas is in full contact with the sidewall of the gas flow chamber and the hot end of the thermoelectric generator, improving the overall temperature uniformity of the sidewalls of the gas flow chamber and enhancing the heat exchange efficiency between the exhaust gas and each thermoelectric generator. It also avoids excessive pressure drop, and then uses a cooler to maintain the low-temperature state of the low-temperature side of the thermoelectric generator, forming a stable temperature difference. This allows for the full utilization of the heat from the exhaust gas and improves the efficiency of exhaust gas power generation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the system in this embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the overall exploded structure of the system in an embodiment of this utility model;

[0022] Figure 3 This is the overall appearance of the gas flow chamber in the embodiment of this utility model;

[0023] Figure 4 This is a schematic diagram of the structure of the turbulence plate inside the gas flow chamber in an embodiment of this utility model;

[0024] Figure 5 In this embodiment of the present invention, (a) is the overall structure of the cooler, and (b) is a schematic diagram of the internal serpentine cooling pipe structure of the cooler;

[0025] Figure 6 The diagram shows the heat transfer simulation results in the embodiments of this utility model, where (a) is a heat transfer simulation diagram without turbulence plates, and (b) to (g) are heat transfer simulation diagrams with turbulence plates.

[0026] Figure 7 The following are schematic diagrams of the central cross-section and wall section of the gas flow chamber in this embodiment of the present invention: (a) central cross-section; (b) wall section;

[0027] Figure 8 This is a schematic diagram of the temperature distribution at the center cross-section of the gas flow chamber in an embodiment of this utility model;

[0028] Figure 9 This is a schematic diagram of the wall temperature cross-section distribution of the gas flow chamber in an embodiment of this utility model;

[0029] Figure 10 This is a linearized distribution diagram of the wall temperature at various time points in the embodiments of this utility model;

[0030] Figure 11 Assembly strength verification in this utility model embodiment: (a) overall deformation; (b) Mises equivalent stress distribution;

[0031] Figure 12 For the cyclic loading embodiments of this utility model: (a) equivalent stress distribution under cyclic loading; (b) cycle life;

[0032] Figure 13 This is a schematic diagram of the harmonic response load in an embodiment of the present invention;

[0033] Figure 14 This is a mode shape diagram of the 9th natural frequency in an embodiment of this utility model;

[0034] Figure 15 This is a mode shape contour plot for harmonic response analysis at the 9th natural frequency in this embodiment of the invention;

[0035] Figure 16 This is a schematic diagram of the GRU neural network structure in an embodiment of this utility model;

[0036] Figure 17 The algorithm calculation quality in this embodiment includes: (a) training loss curve; (b) predicted value distribution; (c) residual distribution; and (d) error distribution histogram.

[0037] Figure 18 For the embodiment of this utility model, at 200s, (a) is a temperature distribution diagram of each test point; (b) is a broken line distribution diagram of the temperature at each test point.

[0038] Figure 19 The following is a schematic diagram illustrating the effect of the baffle on airflow in this embodiment of the present invention: (a) the baffle is parallel to the inflow direction; (b) the baffle is perpendicular to the inflow direction; (c) there is an angle between the baffle and the inflow direction.

[0039] Figure 20 This is a schematic diagram of the Seebeck effect in an embodiment of this utility model.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. Gas flow chamber; 2. Exhaust pipe; 3. Baffle assembly; 31. Baffle plate; 4. Thermoelectric generator; 5. Cooler; 51. Sleeve; 52. Heat dissipation fins; 6. Water cooling pipe; 7. VC heat sink; 8. Connecting flange. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0043] Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0044] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0045] In recent years, semiconductor thermoelectric power generation technology has emerged as a key technology in the field of energy recovery, becoming one of the crucial technologies for energy conservation and emission reduction strategies. This technology is based on the Seebeck effect, where a potential difference is created between two different semiconductor materials under a temperature gradient, enabling the direct conversion of heat energy into electrical energy. It boasts significant advantages such as compact structure, zero noise, no wear from moving parts, and zero emissions, demonstrating immense value, especially in the field of industrial waste heat recovery. The thermoelectric power generation module, by coupling exhaust gas waste heat with environmental cooling, can recover energy emitted as waste heat after fuel combustion, thereby improving energy utilization efficiency.

[0046] As an important technological carrier for energy conservation and emission reduction strategies, exhaust gas differential power generation systems have made significant progress in recent years in optimizing heat-to-electricity conversion efficiency. However, existing exhaust gas differential power generation systems have limited heat exchange capacity for exhaust gases, making it difficult to fully improve the heat exchange rate and resulting in low power generation efficiency. To address this issue, a power generation structure design based on the residual heat of vehicle exhaust gases is proposed.

[0047] See Figures 1 to 5As shown, in order to effectively improve the heat exchange rate of exhaust gas and enhance the efficiency of thermoelectric power generation, this embodiment provides a power generation system based on the waste heat of automotive exhaust gas, including a gas flow chamber 1, a baffle assembly 3, and a power generation component. Specifically, the gas flow chamber 1 is installed between the particulate filter and the muffler of the exhaust pipe 2. The gas flow chamber 1 has a gas inlet and a gas outlet arranged opposite to each other. The overall structure of the gas flow chamber 1 adopts a square design (i.e., the cross-section of the gas flow chamber 1 is preferably rectangular), and the gas inlet and gas outlet of the gas flow chamber 1 are arranged facing each other. The gas inlet and gas outlet are detachably connected to the front and rear ends of the exhaust pipe 2 respectively through connecting flanges 8 and flange gaskets. The baffle assembly 3 is disposed inside the gas flow chamber 1 and includes multiple baffles 31. The multiple baffles 31 are linearly distributed in multiple rows in the direction from the gas inlet to the gas outlet inside the gas flow chamber 1, and the baffles 31 are obliquely fixed on the side wall of the gas flow chamber 1. Furthermore, the baffle 31 has a gap with the side wall of the gas flow chamber 1, thereby guiding the airflow path into the gas flow chamber 1 through the baffle 31 to achieve cyclic contact between the airflow and the wall of the gas flow chamber 1. The power generation component includes a thermoelectric generator 4 and a cooler 5. Multiple thermoelectric generators 4 are preferably provided, and the multiple thermoelectric generators 4 are evenly distributed on each outer side wall of the gas flow chamber 1. The high-temperature side of the thermoelectric generator 4 is attached to the outer side wall of the gas flow chamber 1, and the low-temperature side is connected to the cooler 5. The cooler 5 is used to regulate the temperature of the low-temperature side of the thermoelectric generator 4 to achieve a stable temperature difference between the high-temperature side and the low-temperature side of the thermoelectric generator 4. Then, the thermoelectric generator 4 is used to connect to vehicle electrical appliances or vehicle battery. For traditional fuel vehicles, the thermoelectric generator 4 can be directly connected to the electrical circuit of the vehicle or connected to the battery; for new energy vehicles, the thermoelectric generator 4 is directly connected to the battery.

[0048] See Figure 2 and Figure 5 As shown, further, in order to improve heat dissipation capacity and ensure the temperature difference between the high-temperature side and the low-temperature side of the thermoelectric generator 4, the cooler 5 includes a split-type sleeve 51. The sleeve 51 is wrapped around the outside of the gas flow chamber 1 and is fixedly connected to the gas flow chamber 1 by bolts. The inner wall of the sleeve 51 is in contact with the low-temperature side of the thermoelectric generator 4, and heat dissipation fins 52 are evenly distributed on the outer wall of the sleeve 51.

[0049] See Figure 5As shown, furthermore, to improve heat dissipation and ensure a stable temperature difference between the high-temperature and low-temperature sides of the thermoelectric generator 4, a water-cooling pipe 6 is serpentinely arranged inside the side wall of the housing 51. The water-cooling pipe 6 is filled with coolant, with one end connected to the outlet of the vehicle's built-in water pump and the other end connected to the inlet of the water pump. A radiator is also connected in series with the water-cooling pipe 6, thereby achieving coolant circulation and heat exchange, and ensuring stable power generation by the thermoelectric generator 4. Specifically, for gasoline vehicles, the coolant is connected to the rear of the vehicle's intercooler via pipes, and the coolant is circulated using a water pump to dissipate heat. For new energy vehicles, the coolant uses the same heat exchange method as the battery pack coolant, or the battery pack coolant can be used directly, with coolant circulation and heat exchange achieved through a water pump.

[0050] See Figure 2 As shown, in order to ensure that the thermoelectric generator 4 is heated evenly and improve the efficiency of the thermoelectric generator 4, a VC heat exchange plate 7 is provided between the thermoelectric generator 4 and the side wall of the gas flow chamber 1.

[0051] See Figure 4 As shown, furthermore, in order to improve the heat exchange of the exhaust gas flow into the gas flow chamber 1, the tilt angle of the baffle 31 is generally set to 30°~60°, and the upper end of the baffle 31 in the tilt direction is provided with a gap between the baffle 31 and the side wall of the gas flow chamber 1, that is, the angle between the baffle 31 and the line connecting the center point of the gas inlet and the gas outlet of the gas flow chamber 1. Preferably, the angle of the baffle 31 is set to 45°, which can effectively enhance the heat exchange performance of the gas flow chamber 1 while ensuring smooth exhaust gas discharge.

[0052] Furthermore, to ensure uniform heating of the thermoelectric generator 4 and improve its efficiency, each row of baffles 31 is equally spaced, with the spacing between two adjacent baffles 31 being 20mm to 70mm. Preferably, the spacing between two adjacent baffles 31 is set to 50mm.

[0053] Based on the above structural design, the following sections will conduct further structural analysis, structural dimension design optimization analysis, structural simulation verification, and heat transfer efficiency analysis:

[0054] 1. Structural Composition

[0055] (1) Connecting flange 8 and flange gasket

[0056] In this design, the connecting flange 8, as a key component connecting to the front and rear exhaust pipes 2, adopts a concave-convex surface structure, such as... Figure 2 As shown, the concave-convex surface design increases the sealing contact area, reducing the risk of gas leakage and avoiding abnormal noises during operation. Simultaneously, this design exhibits good stability under high temperature and vibration environments, ensuring the long-term reliability of the equipment.

[0057] The flange material is aluminum alloy, taking into account cost, lightweight, thermal conductivity, corrosion resistance, and compatibility with other structural materials. Aluminum alloy has a lower cost, which helps control manufacturing expenses; its good thermal conductivity and corrosion resistance ensure stable performance at high temperatures and avoid discontinuities with other materials, ensuring structural integrity and durability.

[0058] To enhance sealing performance, the flange uses a spiral wound metal gasket, such as... Figure 3 As shown, this gasket is made of alternating metal strips and non-metallic filler materials, exhibiting excellent high-temperature adaptability and wear resistance. It can maintain a stable seal in high-temperature environments, extending its service life, reducing replacement frequency, and offering high cost-effectiveness, meeting the economic needs of practical applications.

[0059] (2) Gas flow chamber 1

[0060] The main function of gas flow chamber 1 is to efficiently guide airflow, optimize its flow path, and reduce flow resistance, thereby improving the system's heat transfer efficiency. The overall structure adopts a square design, such as... Figure 3 As shown, this design aims to increase the contact area of ​​the thermoelectric generator 4. Furthermore, the square structure facilitates modular design, making the installation and disassembly of the thermoelectric generator 4 and its cooler 5 more convenient, and providing flexibility for system maintenance and expansion.

[0061] The gas flow chamber 1 is made of aluminum alloy, which is consistent with the connecting flange 8. This reduces manufacturing costs, ensures the integrity of the structure, and effectively avoids thermal stress concentration and corrosion problems caused by dissimilar materials.

[0062] To enhance heat transfer efficiency, a baffle plate 31 is designed inside the gas flow chamber 1, the structure of which is as follows: Figure 4 As shown. The baffle 31 enhances the vortex, making the airflow within the flow chamber more complex, improving the uniformity of the wall temperature, and significantly improving the heat exchange efficiency between the airflow and the wall. The optimized arrangement of the baffle 31 will be described in detail later, aiming to achieve the best heat transfer effect without significantly increasing flow resistance.

[0063] (3) Cooler 5

[0064] The main function of the cooler 5 is to cool the low-temperature side of the thermoelectric generator 4, thereby maintaining a stable temperature difference between the high-temperature and low-temperature sides of the thermoelectric generator 4 and ensuring the efficient operation of the thermoelectric generator 4. Figure 5As shown in (a), the outer wall of the cooler 5 is designed with air-cooled heat dissipation fins 52. The heat dissipation fins 52 increase the contact area with air, utilizing natural convection and forced convection to dissipate heat into the environment. This design not only improves the heat dissipation efficiency of the cooler 5 but also enhances its stability in high-temperature environments. The geometry and arrangement of the heat dissipation fins 52 are optimized to effectively utilize the airflow generated during vehicle operation, further improving the heat dissipation effect.

[0065] To further enhance heat dissipation, the cooler 5 is internally designed with serpentine water-cooling pipes 6, such as... Figure 5 As shown in (b), this design significantly increases the contact area between the coolant and the inner wall, thereby improving cooling efficiency. The serpentine tube layout allows the coolant to be evenly distributed as it flows through the generator, further enhancing heat transfer. The close fit of the serpentine water-cooling tube 6 to the inner wall ensures that heat can be quickly conducted into the coolant, effectively reducing the temperature of the generator.

[0066] Cooler 5 features a quick-connect threaded interface design, allowing for easy connection to the vehicle's intercooler. This design simplifies the installation and disassembly process, improving system maintainability and flexibility.

[0067] 2. Structural installation and dimensional design

[0068] Thermoelectric power generation needs to balance muffler space adaptation with catalytic converter airflow integrity. Under stable automotive engine operating conditions, the temperature conditions of the pipe section between the particulate filter and the muffler are: steady-state 350℃~370℃, axial gradient ±10℃, radial uniformity 92%, and adaptation module heat dissipation threshold. Therefore, the equipment is installed between the particulate filter and the muffler on the exhaust pipe. To meet the installation requirements of the vehicle's limited space, the overall structural dimensions are designed according to the vehicle body structure, and it is placed within the existing slot of exhaust pipe 2, without the need for a separate slot.

[0069] 3. Structural simulation demonstration

[0070] 3.1 Analysis of the influence of the turbulence vane 31 on heat transfer effect

[0071] To investigate the influence of the spacing of the baffles 31 on the heat transfer effect and wall temperature distribution, baffle 31 structures with spacings of 20mm, 30mm, 40mm, 50mm, 60mm, and 70mm were designed, and transient simulation analysis was performed. The inlet temperature was 611.15K, the inlet velocity was 10m / s, the total calculation time was 10 seconds, the step size was 0.1 seconds, and the heat transfer simulation results at the 10th second were selected for analysis.

[0072] Simulation results show that the spacing of the baffles 31 has a significant impact on the overall temperature distribution. For example... Figure 6 (a) When there is no turbulence plate 31, the overall temperature distribution is relatively uniform, and the overall temperature is low. For example... Figure 6 (b) ~ Figure 6 (g) Corresponding to the spacing of the baffles 31 from 20mm to 70mm respectively, when the baffles 31 are present, the overall temperature distribution is more uniform, the temperature gradient is smaller, and the overall temperature is higher than when there are no baffles 31.

[0073] Take the central cross-section and wall section of gas flow chamber 1, as follows: Figure 7 As shown. Simulation results indicate that the spacing of the spoilers 31 has a significant impact on the cross-sectional temperature distribution. Figure 8 (a) Without the turbulence plate 31, the temperature distribution at the center section is uneven, and the overall temperature is low. For example... Figure 8 (b) ~ Figure 8 (g) When the turbulence plate 31 is present, the temperature distribution of the central section is more uniform and the temperature gradient is smaller than that without the turbulence plate 31, resulting in a higher overall temperature.

[0074] Plot the wall temperature intercept distribution curves at time points of 3 seconds, 5 seconds, 7 seconds, and 10 seconds, respectively. Figure 9 As shown. Analysis was conducted on a segment with side lengths ranging from 150mm to 400mm. Simulation results show that the spacing of the baffles 31 has a significant impact on the temperature distribution along the wall cross section. Without the baffles 31, the wall cross section temperature is as follows: Figure 9 As shown in (a), the temperature distribution of the wall cross-section at different spacings is as follows when the baffle 31 is present. Figure 9 (b) ~ Figure 9 As shown in (g), the wall cross-sectional temperature distribution is relatively uniform for baffles 31 with spacings ranging from 20 mm to 70 mm. The characteristics of the wall cross-sectional temperature distribution at different spacings are shown in Table 3-1. Comparing the data in Table 3-1, the mean and median temperatures are lower when there are no baffles 31. At a spacing of 20 mm, although the mean and median temperatures are higher, the temperature gradient is larger, which may affect heat exchange efficiency. In contrast, the mean and median temperatures at different time points are higher for spacings of 30 mm, 40 mm, 50 mm, 60 mm, and 70 mm, and the temperature gradients are relatively smaller, showing better thermal stability. In particular, the 50 mm and 60 mm spacings achieve a more ideal temperature gradient while maintaining relatively large mean and median temperatures.

[0075] Table 3-1 Temperature distribution characteristics at different spacings

[0076]

[0077] By comprehensively analyzing the linearized temperature distribution of the wall surface temperature of the baffle 31 structure with different spacings, its influence on the wall surface temperature distribution can be more fully evaluated. For example... Figure 10 As shown, the linearized temperature distributions of the spoiler 31 structure with different spacings at 3 seconds, 5 seconds, 7 seconds, and 10 seconds are plotted together. Figure 10 (a) ~ Figure 10 (d) Wall temperature distribution at the above time points. When the spacing of the baffles 31 is 50 mm, the wall temperature distribution is uniform, the temperature gradient is small, and the overall temperature is high. As time increases, the 50 mm spacing structure maintains high temperature uniformity and heat transfer efficiency throughout the entire time range.

[0078] In summary, the 50mm pitch baffle 31 structure exhibits the best overall performance in terms of heat transfer efficiency and wall temperature distribution uniformity, and is suitable for operating conditions with an inlet temperature of 611.15K and an inlet flow velocity of 10m / s.

[0079] 3.2 Structural strength verification and reliability analysis

[0080] When performing strength verification on the gas flow chamber 1 and the mounting bracket for the thermoelectric generator 4, due to the complexity of the simulation and limitations of the calculation conditions, this paper adopts a simplified finite element model, ignoring secondary structures such as the surface air-cooled fins and the thermoelectric generator 4 cooler 5, and only assembling one set of brackets for calculation. The strength verification focuses on the geometric discontinuities of the gas flow chamber 1 and the strength and lifespan of the connecting screws and screw holes of the mounting bracket for the thermoelectric generator 4.

[0081] In the simulation analysis, the gas flow chamber 1 and the thermoelectric generator 4 are mounted on aluminum alloy brackets, and the screws are made of manganese steel. The boundary conditions are set to have fixed inlet and outlet flanges to simulate the support connection method under actual working conditions, while a small displacement is applied to the outside to simulate the effect of external vibration.

[0082] Simulation results are as follows Figure 11 As shown, under displacement load, the maximum Mises stress in gas chamber 1 is 64.66 MPa, which is far lower than the allowable stress of 138 MPa for aluminum alloy at 250℃. The stress concentration areas are mainly present at bolted connections and the neck region, but the stress values ​​in these areas are still lower than the allowable stress of aluminum alloy.

[0083] The result of the loop loading is as follows Figure 12 As shown, the maximum equivalent alternating stress in gas chamber 1 is 129.32 MPa, which is still lower than the allowable stress of 138 MPa, indicating that the structure has sufficient fatigue strength reserve under cyclic loading. The fatigue life distribution diagram shows that most areas have high fatigue life and can withstand long-term cyclic loading. The overall life reaches 1e. 8 In the next cycle, the lifetime of the stress concentration zone is higher than 2e. 6 The cycle length is 7.08e, while the bolt life is higher than 7.08e. 5 The experiment was repeated several times. The results show that the structure has high reliability and durability under actual working conditions.

[0084] 3.3 Analysis of Harmonic Response of Gas Flow Chamber

[0085] A response analysis was performed on the designed structure. Since the external load on the structure is the vibration load caused by engine vibration, a random waveform was used to simulate the non-uniform vibration caused by the engine during the harmonic response analysis. The applied harmonic response load is as follows: Figure 13 As shown in Table 3-2, the analysis was performed with the flange face fixed on one side, selecting the first nine frequencies. The mode shapes for the 9th-order constrained modal harmonic response analysis of this structure are shown in Table 3-2. Figure 14 , Figure 15 As shown.

[0086] Table 3-2 9th Order Frequency Analysis

[0087]

[0088] Comparative analysis revealed that the frequency ratio of the harmonic response frequency to the natural frequency is not within the resonance range, and the natural frequency distribution is relatively dense, while the harmonic response frequency distribution is relatively dispersed. There is no obvious overlap between the two, which can effectively avoid resonance.

[0089] 4. Spoiler Spacing Prediction Model Based on GRU Neural Network

[0090] 4.1 Selection and Processing of Training Samples

[0091] To determine the appropriate spacing range of spoilers corresponding to the two characteristic parameters of gas velocity and temperature, a parametric scanning simulation method was used to calculate and determine the applicable spacing intervals for these two parameters. The gas velocity and temperature within the selected range were used as inputs to a neural network, and the spoiler spacing was used as the network's output. 3000 sets of data were generated using the simulation model and were then used as the input values ​​and labels for the neural network.

[0092] 4.2 Neural Network Model Construction and Training

[0093] This scheme, based on a GRU neural network model, models the potential patterns in sequence data, generating regression equations between gas flow rate, temperature, and the spacing parameters of the baffles. The constructed GRU neural network structure is as follows: Figure 16 As shown, the hidden layer activation function is Sigmoid (S-shaped growth curve), and the output layer activation function is Tanh (hyperbolic tangent function).

[0094] The hyperparameter combinations obtained by optimizing the neural network model structure using Bayesian methods are shown in Table 4-1. The dataset generated during the selection and processing of training samples was divided into a training set of 80% and a test / validation set of 20%. The data was then input into the neural network for training.

[0095] Table 4-1 Hyperparameter Combinations

[0096]

[0097] 4.3 Validation of Neural Network Model

[0098] Model computational quality such as Figure 4-2 As shown. By Figure 17 (a) Loss curve analysis shows that the model's loss value gradually decreases with the increase of the number of iterations, from an initial value of approximately 1.8 to below 0.8, and gradually converges and stabilizes in the later stages of training; Figure 17 (b) Scatter plot analysis of predicted and actual values ​​shows that the predicted and actual values ​​are highly consistent, with most points concentrated near the diagonal; from Figure 17 (c) Analysis of the residual distribution plot shows that the residuals are distributed around the zero line, indicating that the prediction error of the model has randomness and no obvious systematic bias; Figure 17 (d) Histogram analysis of error distribution shows that the error distribution is close to a normal distribution and is concentrated in a relatively small range.

[0099] To verify the performance of the proposed neural network model, this paper compares the performance of algorithms such as RF (Random Forest), LSTM (Long Short-Term Memory), CNN (Convolutional Neural Network), RNN (Recurrent Neural Network), and GRU (Ground-Robust Logic), using R² as the performance metric. The performance comparisons of each algorithm are shown in Table 4-2.

[0100] Table 4-2 Performance Comparison of Various Neural Network Algorithms

[0101]

[0102] A comprehensive analysis of the tabular data shows that GRU exhibits significant advantages in both fitting ability and training efficiency. In terms of R², GRU's value is 0.95, close to LSTM (0.97), indicating its high accuracy in capturing data patterns. However, GRU's training time is only 1.2 seconds per epoch, far lower than LSTM's 6.8 seconds per epoch, demonstrating higher computational efficiency. In contrast, while RF has the shortest training time (0.9 seconds per epoch), its R² value is only 0.52, indicating significantly insufficient fitting ability; CNN and RNN have moderate fitting abilities, but their training times are relatively long (10.4 seconds and 3.5 seconds per epoch, respectively). Therefore, GRU, while maintaining high fitting ability, significantly reduces training time, achieving a balance between performance and efficiency, making it the preferred algorithm for processing time series data.

[0103] To determine whether the performance difference between the proposed neural network model and other models is statistically significant, this paper first uses Bartlett's test to verify whether the data conforms to a normal distribution and has homogeneity of variance. For those conforming to a normal distribution and having homogeneity of variance, a paired t-test is used; otherwise, Welch's t-test is used. Statistical analysis is shown in Table 4-3. As can be seen from Table 4-3, the performance difference between the GRU model used in this paper and other models is significant, indicating that GRU shows a significant performance improvement in all comparisons.

[0104] Table 4-3 Validation of significant differences in algorithms

[0105]

[0106] The generalization ability of the neural network model was verified by adding random data. Five sets of data combinations not present in the training dataset were randomly generated. Gas flow rate and temperature were input into the network model, and the model output was compared with the generated data, as shown in Table 4-4.

[0107] Table 4-4 Additional Data Validation

[0108]

[0109] Data shows that the neural network demonstrated excellent generalization ability in additional experiments. The error range between the neural network's predicted spoiler spacing and the actual value was only 0.11% to 0.76%, verifying that the model can maintain high prediction accuracy and stability even under unseen input conditions. This indicates that the neural network can effectively capture the complex nonlinear relationship between input variables and spoiler spacing, further confirming its reliability and generalization ability in engineering applications.

[0110] 5. Verification of experimental results

[0111] 5.1 Temperature Result Verification

[0112] Based on the above analysis, the 50mm spacing baffle 31 structure exhibits the best overall performance in terms of heat transfer efficiency and wall temperature distribution uniformity. As shown in Table 5-1, six equally spaced test points were set inside the exhaust pipe 2 with 50mm spacing baffle 31, and the temperature experimental results were analyzed. Regarding temperature changes over time, initially (0s~50s), the temperature showed a significant upward trend, especially at the 150mm position, where the temperature rapidly increased from 305.8K to 485.3K. As the system operating time increased (50s~150s), the temperature continued to rise, but the rate of increase slowed significantly. In the final stage (150s~200s), the temperature began to decrease. Regarding temperature distribution at different locations, at the same time point, the temperature at the 150mm position was consistently the highest, while the temperature at the 400mm position was the lowest. Over time, the temperature differences between locations gradually decreased, and when the experimental time reached 200s, the temperature changes at each location tended to stabilize.

[0113] Table 5-1 Experimental results of internal temperature of exhaust pipe (K)

[0114]

[0115] The experimental data and simulation results are processed and visualized to obtain the following results: Figure 18 As shown, the temperature at each test point inside exhaust pipe 2 reached a stable state at 200s, providing basic data for further analysis of the thermal performance of exhaust pipe 2.

[0116] 5.2 Verification of Power Generation Results

[0117] Introduction to the Seebeck effect:

[0118] The Seebeck effect is a thermoelectric phenomenon that generates a voltage difference between two different conductors or semiconductors when there is a temperature difference at their junction. This phenomenon was discovered in 1821 by German physicist Thomas Johann Seebeck, and its basic principle is based on the difference in electron work function and effective electron density between the two materials.

[0119] like Figure 20 As shown, on the high-temperature side, the higher temperature allows for a wider energy distribution of electrons, causing electrons to diffuse from higher-energy materials to lower-energy materials. This results in the accumulation of electrons on the low-temperature side and the loss of electrons on the high-temperature side, thus creating charge separation and a potential difference. The basic principle formula of the Seebeck effect is shown in (1-1):

[0120] (1-1)

[0121] In the formula, VFor the generated voltage difference ；S A and S B These are the Seebeck coefficients; T 1 and T 2 These are the temperatures on the low-temperature side and the high-temperature side. If... S A and S B If the temperature is constant and does not change with temperature, then formula (1-1) can be simplified to:

[0122] (1-2)

[0123] Thermoelectric power generation technology is based on the Seebeck effect, utilizing the properties of thermoelectric materials to directly convert heat energy into electrical energy. When two different thermoelectric materials form a closed circuit, a current will be generated in the circuit if a temperature difference exists between their ends. The physical basis of this phenomenon is that the temperature gradient causes a change in the distribution of charge carriers, thus creating a potential difference. The performance of thermoelectric materials is typically determined by their thermoelectric figure of merit (TFP). ZT The evaluation is performed using formula (1-3), and the specific calculation is shown in formula (1-3):

[0124] (1-3)

[0125] In the formula, S The Bessick coefficient; Electrical conductivity; The thermal conductivity of the material; T Here, is the absolute temperature. An ideal thermoelectric material should possess a high Seebeck coefficient, high electrical conductivity, and low thermal conductivity to achieve efficient energy conversion. In thermoelectric power generation applications, the power output can be expressed as:

[0126] (1-4)

[0127] In the formula, The temperature difference between the cold and high temperature sides. A For cross-sectional area, L Let be the material length. As shown in formula (1-4), a larger temperature difference can significantly increase power output, increasing the cross-sectional area helps increase the current, while shortening the material length reduces resistance, thus improving overall performance. Therefore, optimizing these parameters is crucial for improving the efficiency of thermoelectric power generation systems. Furthermore, the power output of thermoelectric power generation is also affected by the temperature uniformity of the overall structure.

[0128] Thermoelectric figure of merit ( ZTBesegg coefficient is a key indicator for evaluating the performance of thermoelectric materials; a higher value indicates a higher thermoelectric conversion efficiency. Based on the fundamental principle of the Seebeck effect and according to experimental conditions, the technical parameters of the thermoelectric generator selected in this scheme are as follows: Electrical conductivity Material thermal conductivity Take the absolute temperature of exhaust pipe 2 at 150mm at 200s. Substitute into the formula The calculation results show that, hour, ZT The value is 1.45. This result indicates that the thermoelectric material of this structure has a high thermoelectric conversion efficiency at this temperature.

[0129] In thermoelectric power generation applications, power output is one of the key indicators for evaluating the performance of thermoelectric generators. Based on the basic principle of the Seebeck effect, and according to experimental conditions and optimization strategies, the technical parameters of the thermoelectric generator are as follows: ; ; ; ; The selected thermoelectric generator has the specifications described above, and its dimensions are as follows: , Substitute into the formula The calculation results show that, under given parameter conditions, the power output of the thermoelectric generator is 3.47W.

[0130] 6. Based on the above design and optimization, this solution has the following outstanding advantages:

[0131] 1) Design of spoiler 31

[0132] Traditional exhaust pipes 2 typically have a smooth interior design. Adding a baffle plate 31 to the device can extend the residence time of the exhaust gas and increase airflow turbulence, thereby allowing heat to be fully transferred to the high-temperature side of the thermoelectric generator 4 and enhancing the heat exchange efficiency between the exhaust gas and the thermoelectric generator module.

[0133] like Figure 19 (b) If the spoiler 31 is placed vertically, it will lead to a significant increase in pressure drop, affecting the engine back pressure and causing localized heat concentration; Figure 19 (a) If the baffle 31 is placed horizontally, it will be parallel to the airflow direction, thus having almost no effect on disturbing the airflow, resulting in a short residence time for the exhaust gas and low heat transfer efficiency. Figure 19(c) When the baffle 31 is placed at an angle, the general design of the baffle 31's tilt angle is between 30° and 60°, preferably 45°. This guides the exhaust gas to form a rotating flow, which not only allows the high-temperature exhaust gas to fully contact the wall of the exhaust pipe 2 and the high-temperature side of the thermoelectric generator 4, improving the overall temperature uniformity, but also avoids excessive pressure drop, allowing the device to perform at its best. Based on the above analysis of the optimal placement of the baffle 31, through thermal simulation analysis of the heat transfer effect and wall temperature distribution under different spacings of the baffle 31, the optimal baffle spacing was determined to be 50mm to achieve the best heat transfer effect.

[0134] 2) Hybrid heat dissipation system design

[0135] The low-temperature side of the thermoelectric generator 4 adopts a dual heat dissipation design combining "serpentine water-cooled pipes 6" and "air-cooled fins," achieving cooling through the combined action of coolant circulation and air convection. The serpentine pipes extend the coolant flow path, enhancing heat dissipation; the air-cooled fins, with their multi-fin arrangement, significantly increase the effective heat dissipation area. Furthermore, when the car travels at a certain speed, the relative velocity between the fins and the air creates forced convection, further enhancing heat dissipation and ensuring that the low-temperature side of the thermoelectric generator 4 maintains a low temperature, thus forming a stable temperature difference.

[0136] 3) Application of VC heat spreader 7

[0137] Using the VC heat exchange plate 7 as the high-temperature side heat conduction medium, the high-temperature waste heat conducted from the exhaust gas is evenly distributed to the high-temperature side surface of the thermoelectric generator 4. The VC heat exchange plate 7 achieves efficient temperature uniformity through phase change heat transfer technology, avoiding the problems of local overheating or insufficient temperature difference, and can make the voltage generated by the thermoelectric generator 4 more stable.

[0138] 4) Optimized layout of temperature difference plates

[0139] The thermoelectric generator 4 is directly embedded between the exhaust pipe 2 and the heat dissipation system. On the high-temperature side, it is in close contact with the VC heat spreader 7 through liquid metal, and on the low-temperature side, it is in contact with the serpentine water-cooling pipe 6 through liquid metal. The compact layout maximizes the utilization of exhaust gas waste heat while shortening the heat conduction path and reducing waste heat loss.

[0140] 5) Connection flange with raised face structure and sealing design

[0141] Traditional flanges are prone to leakage due to deformation at high temperatures. Using a raised face flange to connect the exhaust pipe 2 to the interface of the designed device can enhance the sealing reliability, prevent heat loss, and ensure the long-term stable operation of the system.

[0142] 6) Spatial layout optimization

[0143] The heat dissipation fins 52 are evenly distributed on each side wall of the sleeve 51, and the sleeve 51 is easy to disassemble and replace for cleaning and maintenance of the heat dissipation fins 52. The structure of each part of the device is compact, adapting to the limited space of the car, and achieving efficient compatibility between the waste heat power generation system and the original vehicle exhaust system.

[0144] 7) Deep Learning-Based Optimization of Spoiler Spacing 31

[0145] A neural network model based on gated recurrent units (GRUs) is used to intelligently optimize the spacing of the baffles 31. By learning the complex nonlinear relationship between gas velocity, temperature and the spacing of the baffles 31 in a large amount of simulation data, the model can adaptively predict the optimal spacing of the baffles 31, thereby achieving efficient heat exchange under different operating conditions.

[0146] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A power generation system utilizing waste heat from automobile exhaust, characterized in that, include: A gas flow chamber (1) is installed between the particulate filter and the muffler in the exhaust pipe (2), the gas flow chamber (1) having a gas inlet and a gas outlet arranged opposite to each other; The turbulence assembly (3) is disposed inside the gas flow chamber (1) and includes multiple turbulence plates (31). The multiple turbulence plates (31) are linearly distributed in multiple rows in the gas flow chamber (1) along the direction from the gas inlet to the gas outlet. The turbulence plates (31) are obliquely fixed on the side wall of the gas flow chamber (1). The turbulence plates (31) are used to guide the flow path of the airflow entering the gas flow chamber (1) so as to realize the cyclic contact between the airflow and the wall of the gas flow chamber (1). The power generation component includes a thermoelectric generator (4) and a cooler (5). The high-temperature side of the thermoelectric generator (4) is attached to the outer wall of the gas flow chamber (1), and the low-temperature side is connected to the cooler (5). The cooler (5) is used to regulate the temperature of the low-temperature side of the thermoelectric generator (4) to achieve a stable temperature difference between the high-temperature side and the low-temperature side of the thermoelectric generator (4). The thermoelectric generator (4) is used to connect to vehicle electrical appliances or vehicle batteries.

2. The power generation system based on the waste heat of automobile exhaust according to claim 1, characterized in that, The gas flow chamber (1) has a rectangular cross-section.

3. The power generation system based on the waste heat of automobile exhaust according to claim 2, characterized in that, The thermoelectric generator (4) is a plurality of such generators, and the plurality of thermoelectric generators (4) are evenly distributed on each outer wall of the gas flow chamber (1).

4. A power generation system utilizing waste heat from automobile exhaust according to claim 1, characterized in that, The cooler (5) includes a split sleeve (51) and heat dissipation fins (52). The sleeve (51) wraps around the outside of the gas flow chamber (1). The inner wall of the sleeve (51) is attached to the low-temperature side of the thermoelectric generator (4). Multiple heat dissipation fins (52) are evenly distributed on the outer wall of the sleeve (51).

5. A power generation system utilizing waste heat from automobile exhaust according to claim 4, characterized in that, The side wall of the sleeve (51) is also provided with a water cooling pipe (6) arranged in a serpentine pattern. The water cooling pipe (6) is filled with coolant. One end of the water cooling pipe (6) is connected to the outlet of the water pump, and the other end is connected to the inlet of the water pump. A radiator is also connected in series on the water cooling pipe (6).

6. A power generation system utilizing waste heat from automobile exhaust according to claim 1, characterized in that, A VC heat exchanger plate (7) is provided between the thermoelectric generator (4) and the side wall of the gas flow chamber (1).

7. A power generation system utilizing waste heat from automobile exhaust according to claim 1, characterized in that, The tilt angle of the baffle (31) is 30°~60°.

8. A power generation system utilizing waste heat from automobile exhaust according to claim 7, characterized in that, Each row of the spoilers (31) is arranged at equal intervals, and the distance between two adjacent spoilers (31) is 20mm~70mm.

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