Integrated vacuum layering heat preservation exhaust pipe thermal management control system and control method thereof

Abstract

The application provides an integrated vacuum layered heat preservation exhaust pipe thermal management control system and a control method thereof. The integrated vacuum layered heat preservation exhaust pipe thermal management control system comprises an exhaust pipe, the exhaust pipe comprising an exhaust inner pipe, a heat preservation sleeve covering the outer side of the exhaust inner pipe, and a vacuum stainless steel heat preservation shell encapsulating the heat preservation sleeve into an integrated body; a pressure difference sensor is arranged on the vacuum stainless steel heat preservation shell and used for monitoring the pressure difference between the inside and outside of the vacuum stainless steel heat preservation shell; a cold start automatic heating module is arranged in the exhaust inner pipe and arranged on the exhaust passage in the front section of the exhaust pipe; a high load waste heat recovery module is in heat exchange connection with the outer wall of the vacuum stainless steel heat preservation shell; an ECU and an audible and light warning device in electric connection with the ECU and used for issuing an audible and light warning when the pressure difference is abnormal, the ECU is also in electric connection with the pressure difference sensor, the cold start automatic heating module, the high load waste heat recovery module and an exhaust temperature sensor respectively.

Description

Technical Field

[0001] This invention relates to the field of automotive parts technology, and in particular to an integrated vacuum layered insulation exhaust pipe thermal management control system and its control method. Background Technology

[0002] Exhaust thermal management has always been a key technology in emission control. The challenge lies in the fact that the exhaust temperature entering aftertreatment devices such as selective catalytic reduction (SCR) and particulate filter (DPF) is too low when the vehicle is cold-started or under low load, preventing the aftertreatment system from reaching its optimal operating range for catalytic conversion efficiency. The exhaust stroke from the engine exhaust to the front end of the aftertreatment system is the main part of exhaust heat loss and temperature drop. Therefore, reducing exhaust temperature loss from the engine to the aftertreatment system through thermal insulation measures is an important method to improve exhaust thermal management performance and aftertreatment catalytic conversion efficiency.

[0003] The patent published on November 30, 2011, with patent number CN102264969A, entitled "Mounting Pad and Pollution Control Device with the Mounting Pad", includes a mounting pad made of basalt material. It is not an insulation device. Its application scope includes, but is not limited to, automobile exhaust pipes. The installation method is a detachable shell component. It only has the insulation effect of a single layer of material. The sealing and insulation reliability after installation need to be improved.

[0004] Existing automotive exhaust pipe insulation devices are mostly used for localized protection to prevent the high temperatures of the exhaust pipe from damaging or deforming parts on the car chassis that are susceptible to high temperatures. The insulation requirements for the exhaust pipe are not high; therefore, they typically involve first making a panel-shaped pad from fire-resistant cloth and insulating cotton, then wrapping it around the exhaust pipe and securing it with clamps. This method of only using fire-resistant cotton pads to wrap the exhaust pipe is not airtight, and the insulating cotton pads are not protected, making them easily scratched, damaged, and contaminated with mud, water, and oil, resulting in an unsightly appearance. Some exhaust pipe wrapping materials use high-silica cloth for the inner and outer layers, with ceramic fiber as the middle layer. Because high-silica cloth is expensive, the manufacturing cost is high, and the assembly process is complex, slow, and inefficient. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide an integrated vacuum layered insulation exhaust pipe thermal management control system and its control method, which overcomes the shortcomings of existing exhaust pipes with poor single-layer material insulation effect, and the need to improve the sealing and insulation reliability after installation. It also addresses the insufficient exhaust thermal management capability under engine cold start and high load conditions, especially the problems of slow temperature rise of aftertreatment during cold start and large waste of exhaust waste heat during high load.

[0006] An integrated vacuum-insulated exhaust pipe thermal management control system includes:

[0007] An exhaust pipe connected to the engine and in an S-shape, the exhaust pipe including an inner exhaust pipe, an insulation sleeve covering the outside of the inner exhaust pipe, and a vacuum stainless steel insulation shell that encapsulates the insulation sleeve as a whole.

[0008] A differential pressure sensor is installed on the vacuum stainless steel insulation shell to monitor the pressure difference between the inside and outside of the vacuum stainless steel insulation shell;

[0009] A cold start automatic heating module is installed inside the exhaust pipe and arranged in the front section of the exhaust passage of the exhaust pipe.

[0010] A high-load waste heat recovery module is connected to the outer wall of the vacuum stainless steel insulated shell for heat exchange.

[0011] The ECU and an audible and visual warning device electrically connected to the ECU for issuing an audible and visual warning when the pressure difference is abnormal, the ECU is also connected to the pressure difference sensor, the cold start automatic heating module, the high-load waste heat recovery module, and a device for collecting exhaust temperature. Electrical connection of the exhaust temperature sensor;

[0012] The ECU determines cold start and high load conditions based on preset operating condition thresholds. Under cold start conditions, it controls the automatic cold start heating module to work. Under high load conditions, it controls the high load waste heat recovery module to work. Under non-cold start and non-high load conditions, it shuts down the automatic cold start heating module and the high load waste heat recovery module, relying solely on the exhaust pipe to achieve exhaust heat preservation. This constitutes an exhaust pipe thermal management system suitable for all operating conditions, including cold start, normal, and high load.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] The exhaust pipe, with its S-shaped bend and the double-layer insulation of the insulation sleeve and the vacuum stainless steel insulation shell, minimizes the drop in exhaust temperature, allowing the exhaust gas to enter the aftertreatment device at a higher temperature. This increases the exhaust temperature at the inlet of the aftertreatment device, improving thermal management performance and catalytic conversion efficiency, effectively reducing exhaust pollutant emissions. Simultaneously, the double-layer insulation of the insulation sleeve and the vacuum stainless steel insulation shell reduces the transfer of high temperature along the pipe wall to the passenger compartment, achieving both engine exhaust insulation and passenger compartment insulation, improving driving and passenger comfort. A differential pressure sensor monitors the dynamic failure status of the vacuum stainless steel insulation shell, i.e., leak detection, and triggers an audible and visual warning system upon detection of a leak. The system features an audible and visual alarm; an automatic cold start heating module is installed, and the ECU determines the cold start condition based on coolant temperature, exhaust temperature, and engine load, adjusting the heating power according to a preset formula. This ensures that the exhaust temperature quickly rises to the optimal operating range of the aftertreatment system while maintaining safety, shortening the time for emissions to exceed standards during cold starts and improving emission control during the cold start phase; a high-load waste heat recovery module is installed, and a high-load determination formula based on load and exhaust temperature is used to control the amount of waste heat recovered. This recovers some heat from the high-temperature exhaust while meeting the minimum temperature requirements of the aftertreatment system. The waste heat can be introduced into the engine coolant circuit or the vehicle heating system, improving the overall vehicle thermal efficiency and achieving a balance between energy saving and emission control.

[0015] Furthermore, the automatic cold start heating module is an electric heating element, which is connected to the vehicle's high-voltage power supply. The ECU controls the heating power by adjusting the pulse width modulation duty cycle of the automatic cold start heating module.

[0016] Furthermore, the high-load waste heat recovery module includes a three-way valve whose input end is connected to the engine outlet and electrically connected to the ECU. The first output end of the three-way valve is connected to the engine return outlet through a waste heat recovery branch. A circulation pump electrically connected to the ECU and a heat exchanger disposed on the outside of the vacuum stainless steel insulation shell are sequentially arranged on the waste heat recovery branch. The second output end of the three-way valve is connected to the engine return outlet through a normal heat dissipation branch. A radiator is disposed on the normal heat dissipation branch. The ECU adjusts the flow rate of coolant flowing through the heat exchanger by adjusting the speed of the circulation pump and the opening of the three-way valve, thereby adjusting the amount of waste heat recovery.

[0017] On the other hand, the present invention also provides a control method for the integrated vacuum layered insulation exhaust pipe thermal management control system as described above, the control method comprising:

[0018] S1. Engine starts, and the ECU controls the exhaust temperature sensor to collect the exhaust temperature. Engine coolant temperature is collected via ECU. Engine speed n and engine load Load provide input signals for subsequent operating condition determination and control output;

[0019] S2. Cold start condition determination: If the cold start condition is met, proceed to step S2.1; if the cold start condition is not met, proceed to step S3.

[0020] S2.1 Entering the cold start automatic heating mode, the ECU activates the cold start automatic heating module and determines the heating power based on the deviation between the exhaust temperature and the target temperature, so that the exhaust temperature rises to the target range;

[0021] S2.2 Cold start heating exit: If the cold start heating exit condition is met, proceed to step S4; otherwise, repeat step S2.1.

[0022] S3. High load condition determination: If the conditions for high load condition are met, proceed to step S3.1; if the conditions for high load condition determination are not met, proceed to step S4.

[0023] S3.1 Entering high-load waste heat recovery mode, the high-load waste heat recovery module is activated by the ECU to recover and utilize waste heat while meeting the minimum temperature requirements of post-processing.

[0024] S3.2 Waste heat recovery exit. If the waste heat recovery exit conditions are met, proceed to step S4; otherwise, repeat step S3.1.

[0025] S4. Enter normal heat preservation mode;

[0026] The ECU continuously collects differential pressure signals from the differential pressure sensor under various operating conditions and correlates differential pressure changes, engine speed n, and engine load. When the differential pressure change amplitude exceeds the preset differential pressure threshold and does not match the characteristics of normal operating conditions, it is determined that the vacuum stainless steel insulation shell is leaking or the vacuum has failed. The ECU outputs a control command to the audible and visual warning device to trigger the audible and visual alarm, and at the same time shuts down the cold start automatic heating module and the high-load waste heat recovery module, retaining only the basic exhaust function of the exhaust channel.

[0027] Furthermore, step S2 specifically includes:

[0028] For cold start condition determination, the ECU uses the following relationship to determine whether the cold start condition is met:

[0029] When the engine coolant temperature Less than or equal to the cold start temperature threshold And the engine speed n is less than or equal to the upper limit threshold of cold start speed n _cold_th At the same time, the engine load is less than or equal to the upper limit threshold of the cold start load. _cold_thWhen this happens, the cold start determination value F will be set. _cold If the condition for a cold start is met, set the value to 1 and proceed to step S2.1; otherwise, set the cold start determination value F to 1. _cold Set to 0; if the condition for determining the cold start condition is not met, proceed to step S3.

[0030] Furthermore, step S2.1 specifically includes:

[0031] Cold start determination value F _cold When the value is 1, the ECU determines the exhaust temperature. and the target temperature of the post-processing inlet The deviation between the target heating power of the cold start automatic heating module is calculated. The target heating power The following relationship must be satisfied:

[0032]

[0033] In the formula, This is the heating gain coefficient. This represents the maximum output power of the automatic heating module during cold start.

[0034] The ECU determines the target heating power of the automatic heating module based on the cold start requirements. Generate an electric heating duty cycle control command to automatically heat the exhaust gas, raising the exhaust temperature to the target range.

[0035] Furthermore, step S2.2 specifically includes:

[0036] During the continuous cold start self-heating mode, when the engine coolant temperature... Greater than or equal to the cold start temperature threshold Add cold start temperature hysteresis ΔT _cold Or the cold start time t is greater than or equal to the maximum cold start duration. When this happens, the cold start determination value F will be set. _cold Set the value back to 0. If the condition for cold start heating exit is met, proceed to step S4; otherwise, repeat step S2.1.

[0037] Furthermore, step S3 specifically includes:

[0038] To determine whether normal operating conditions are met under high load conditions, the ECU uses the following relationship:

[0039] When the engine load is greater than or equal to the high load threshold load _high_on And exhaust temperature Greater than or equal to the waste heat utilization temperature threshold When that happens, the high load judgment value F will be set._high If the condition is met (high load condition), proceed to step S3.1; otherwise, set the high load condition value F to 1. _high Set to 0; if the condition for determining high load is not met, proceed to step S4.

[0040] Furthermore, step S3.1 specifically includes:

[0041] Cold start determination value F _cold The value F is equal to 0 and is a high-load judgment value. _high When equal to 1,

[0042] ECU based on exhaust temperature Minimum exhaust temperature allowed at the aftertreatment inlet Calculate the deviation between the control commands of the circulating pump The control command The following relationship must be satisfied:

[0043] ;

[0044] In the formula, This represents the waste heat recovery gain coefficient. The value ranges from 0 to 1;

[0045] ECU according to control commands Adjust the speed of the circulating pump and the opening of the three-way valve to continuously regulate the flow rate of the coolant through the heat exchanger as the exhaust temperature changes.

[0046] Furthermore, step S3.2 specifically includes:

[0047] During the continuous high-load waste heat recovery mode, when the engine load is less than or equal to the high-load shutdown threshold load... _high_off Or exhaust temperature Less than or equal to the waste heat utilization temperature threshold Subtract the high-load temperature hysteresis ΔT _hr When, then F _high Set the value back to 0. If the condition for exiting waste heat recovery is met, proceed to step S4; otherwise, repeat step S3.1. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the overall structure of the integrated vacuum layered insulation exhaust pipe thermal management control system in Embodiment 1 of the present invention;

[0049] Figure 2 This is a schematic diagram of the radial cross-section of the exhaust pipe in Embodiment 1 of the present invention;

[0050] Figure 3This is a schematic diagram of the overall structure of the high-load waste heat recovery module in Embodiment 1 of the present invention;

[0051] Figure 4 This is a schematic diagram of the control method of the integrated vacuum layered insulation exhaust pipe thermal management control system in Embodiment 2 of the present invention;

[0052] Figure 5 This is a flowchart illustrating the operation of the differential pressure sensor in Embodiment 2 of the present invention;

[0053] Explanation of key component symbols:

[0054]

[0055] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0056] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0057] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0059] Example 1

[0060] Please see Figures 1 to 3 The integrated vacuum layered insulation exhaust pipe thermal management control system in Embodiment 1 of the present invention includes:

[0061] An exhaust pipe 1 connected to the engine and in an S-shape includes an inner exhaust pipe 101, an insulation sleeve 102 covering the outside of the inner exhaust pipe 101, and a vacuum stainless steel insulation shell 103 that encapsulates the insulation sleeve 102 into one piece.

[0062] Specifically, in this embodiment, the insulation sleeve 102 is made of woven basalt fiber with a thickness of 3mm-5mm. The main component of basalt fiber is woven silica fiber. This material has high strength, permanent flame retardancy, short-term temperature resistance above 1000℃, and can be used for a long time in a temperature environment of 760℃. Moreover, the wrapping thickness is thin, which can achieve wrapping with small gaps. The vacuum stainless steel insulation shell 103 is made of stainless steel and tightly wraps the insulation sleeve 102 to form an organic insulation layer, which enhances the insulation effect of the exhaust pipe 1.

[0063] A differential pressure sensor 2 is installed on the vacuum stainless steel insulation shell 103 to monitor the pressure difference between the inside and outside of the vacuum stainless steel insulation shell 103;

[0064] The cold start automatic heating module 5 is installed inside the exhaust pipe 101 and arranged in the front exhaust passage of the exhaust pipe 1.

[0065] The high-load waste heat recovery module 6 is connected to the outer wall of the vacuum stainless steel insulated shell 103 for heat exchange.

[0066] ECU3 and an audible and visual warning device 4 electrically connected to ECU3 for issuing an audible and visual warning when the pressure difference is abnormal. ECU3 is also connected to the differential pressure sensor 2, the cold start automatic heating module 5, the high-load waste heat recovery module 6, and a device for collecting exhaust temperature. The exhaust temperature sensor 7 is electrically connected;

[0067] The ECU3 determines the cold start condition and the high load condition based on a preset operating condition judgment threshold. In the cold start condition, it controls the cold start automatic heating module 5 to work. In the high load condition, it controls the high load waste heat recovery module 6 to work. In the non-cold start and non-high load conditions, it shuts down the cold start automatic heating module 5 and the high load waste heat recovery module 6, and relies solely on the exhaust pipe 1 to achieve exhaust heat preservation. This constitutes an exhaust pipe thermal management system suitable for all operating conditions, including cold start, normal and high load.

[0068] Understandably, the exhaust pipe 1, with its S-shaped bend and the double-layer insulation provided by the insulation sleeve 102 and the vacuum stainless steel insulation shell 103, can minimize the drop in exhaust temperature, allowing the exhaust gas to enter the aftertreatment device at a higher temperature. This increases the exhaust temperature at the inlet of the aftertreatment device, improving thermal management performance and catalytic conversion efficiency, effectively reducing exhaust pollutant emissions. Simultaneously, the double-layer insulation of the insulation sleeve 102 and the vacuum stainless steel insulation shell 103 reduces the transfer of high temperature along the pipe wall to the passenger compartment, achieving engine exhaust insulation and passenger compartment insulation, improving driving and passenger comfort. The differential pressure sensor 2 monitors the dynamic failure status of the vacuum stainless steel insulation shell 103, i.e., leak detection, and... In the event of a leak, an audible and visual alarm is triggered by the aforementioned audible and visual warning device 4. By setting up the automatic cold start heating module 5, and with the ECU 3 determining the cold start condition based on the coolant temperature, exhaust temperature, and engine load, the heating power is adjusted according to a preset formula. Under the premise of ensuring safety, the exhaust temperature is rapidly raised to the optimal operating range of the aftertreatment, shortening the time of exceeding emission standards during cold starts and improving the emission control level during the cold start phase. By setting up the high-load waste heat recovery module 6, and using a high-load determination formula based on load and exhaust temperature to control the amount of waste heat recovery, a portion of the heat is recovered from the high-temperature exhaust while meeting the minimum temperature requirements of the aftertreatment. This waste heat can be introduced into the engine coolant circuit or the vehicle heating system, improving the overall vehicle thermal efficiency and achieving a balance between energy saving and emission control.

[0069] Furthermore, the automatic cold start heating module 5 is an electric heating element, and the automatic cold start heating module 5 is connected to the vehicle's high-voltage power supply. The ECU 3 controls the heating power by adjusting the pulse width modulation duty cycle of the automatic cold start heating module 5.

[0070] Understandably, the automatic cold start heating module 5 is powered by the vehicle's high-voltage power supply and can actively heat the engine when the coolant temperature is low and the exhaust temperature is insufficient, thereby accelerating the ignition of the aftertreatment system and reducing cold start emissions. The ECU 3 adjusts the heating power through PWM based on the deviation between the exhaust temperature and the target value to avoid overheating or insufficient heating. The automatic cold start heating module 5 only works during the cold start phase and does not increase energy consumption during normal operation, which is in line with the trend of energy conservation and emission reduction.

[0071] Furthermore, the high-load waste heat recovery module 6 includes a three-way valve 61 whose input end is connected to the engine outlet and electrically connected to the ECU 3. The first output end of the three-way valve 61 is connected to the engine return port through a waste heat recovery branch. A circulation pump 62 electrically connected to the ECU 3 and a heat exchanger 63 located outside the vacuum stainless steel insulation shell 103 are sequentially arranged on the waste heat recovery branch. The second output end of the three-way valve 61 is connected to the engine return port through a normal heat dissipation branch. A radiator 64 is arranged on the normal heat dissipation branch. The ECU 3 adjusts the flow rate of coolant flowing through the heat exchanger 63 by adjusting the speed of the circulation pump 62 and the opening of the three-way valve 61, thereby adjusting the amount of waste heat recovery.

[0072] Understandably, the high-load waste heat recovery module 6 is coupled to the engine coolant circuit through the heat exchanger 63, and uses exhaust waste heat to heat the coolant under high load, thereby improving engine thermal efficiency or for vehicle interior heating; the ECU3 controls the coolant flow through the three-way valve 61 and the circulation pump 62 to ensure that the waste heat recovery does not affect the after-treatment temperature requirements; the high-load waste heat recovery module 6 is organically integrated with the engine cooling system, without adding too many independent components, making it easy to apply on existing vehicle platforms.

[0073] Example 2

[0074] Please see Figures 4-5 Embodiment 2 of the present invention also provides a control method for the integrated vacuum layered insulation exhaust pipe thermal management control system as described above, the control method comprising:

[0075] S1. Engine starts, and ECU3 controls exhaust temperature sensor 7 to collect exhaust temperature. Engine coolant temperature is collected via ECU3. Engine speed n and engine load Load provide input signals for subsequent operating condition determination and control output;

[0076] S2. Cold start condition determination: If the cold start condition is met, proceed to step S2.1; if the cold start condition is not met, proceed to step S3.

[0077] Furthermore, step S2 specifically includes:

[0078] To determine whether the cold start condition is met, ECU3 uses the following relationship:

[0079] When the engine coolant temperature Less than or equal to the cold start temperature threshold And the engine speed n is less than or equal to the upper limit threshold of cold start speed n _cold_thAt the same time, the engine load is less than or equal to the upper limit threshold of the cold start load. _cold_th When this happens, the cold start determination value F will be set. _cold If the condition for a cold start is met, set the value to 1 and proceed to step S2.1; otherwise, set the cold start determination value F to 1. _cold Set to 0; if the condition for determining the cold start condition is not met, proceed to step S3.

[0080] Understandably, in response to the shortcomings of traditional methods that rely solely on water temperature or time to determine cold starts, this invention employs multi-parameter collaborative determination, simultaneously considering coolant temperature, engine speed, and load. This avoids erroneous triggering of cold start heating under low water temperature but high load conditions, resulting in more accurate determination. Furthermore, the threshold can be calibrated to adapt to different engine and emission regulations, improving control robustness and making it more suitable for real-world driving scenarios.

[0081] S2.1 Entering the cold start automatic heating mode, the ECU3 activates the cold start automatic heating module 5 and determines the heating power based on the deviation between the exhaust temperature and the target temperature, so that the exhaust temperature rises to the target range;

[0082] Furthermore, step S2.1 specifically includes:

[0083] Cold start determination value F _cold When the value is 1, the ECU determines the exhaust temperature. and the target temperature of the post-processing inlet The deviation between the target heating power of the cold start automatic heating module is calculated. The target heating power The following relationship must be satisfied:

[0084]

[0085] In the formula, This is the heating gain coefficient. This represents the maximum output power of the automatic heating module during cold start.

[0086] The ECU determines the target heating power of the automatic heating module based on the cold start requirements. Generate an electric heating duty cycle control command to automatically heat the exhaust gas, raising the exhaust temperature to the target range.

[0087] Understandably, compared to traditional electric heating which often uses constant power or simple on / off control, this invention uses closed-loop feedback regulation, which adjusts the heating power in real time according to the deviation between the exhaust temperature and the target value, avoiding excessive temperature fluctuations and making the temperature control more stable; it also minimizes the heating power output, reduces energy consumption, and prevents overheating damage to the heating element, thereby saving energy and extending the life of the element; at the same time, it uses upper and lower limit and proportional control, which is easy to implement in ECU3.

[0088] S2.2 Cold start heating exit: If the cold start heating exit condition is met, proceed to step S4; otherwise, repeat step S2.1.

[0089] Furthermore, step S2.2 specifically includes:

[0090] During the continuous cold start self-heating mode, when the engine coolant temperature... Greater than or equal to the cold start temperature threshold Add cold start temperature hysteresis ΔT _cold Or the cold start time t is greater than or equal to the maximum cold start duration. When this happens, the cold start determination value F will be set. _cold Set the value back to 0. If the condition for cold start heating exit is met, proceed to step S4; otherwise, repeat step S2.1.

[0091] Understandably, to avoid premature termination or prolonged heating, this invention introduces a temperature hysteresis and time protection mechanism. The temperature hysteresis avoids repeated entry / exit from the cold start mode near the threshold, thereby preventing frequent mode switching. A maximum duration is set to prevent indefinite heating due to sensor failure, serving as a safety backup limit. After termination, it automatically switches to the normal heat preservation mode for a smooth transition.

[0092] S3. High load condition determination: If the conditions for high load condition are met, proceed to step S3.1; if the conditions for high load condition determination are not met, proceed to step S4.

[0093] Furthermore, step S3 specifically includes:

[0094] For high-load operating condition determination, ECU3 uses the following relationship to determine whether normal operating conditions are met:

[0095] When the engine load is greater than or equal to the high load threshold load _high_on And exhaust temperature Greater than or equal to the waste heat utilization temperature threshold When that happens, the high load judgment value F will be set. _high If the condition is met (high load condition), proceed to step S3.1; otherwise, set the high load condition value F to 1. _high Set to 0; if the condition for determining high load is not met, proceed to step S4.

[0096] Understandably, traditional waste heat recovery systems often simply activate based on exhaust temperature. This invention proposes a dual judgment based on load and temperature: recovery is only activated when the engine load is high enough to ensure sufficient exhaust energy and avoid false recovery under low load; heat exchange only occurs when the exhaust temperature reaches a usable threshold, improving recovery effectiveness and ensuring recovery efficiency; load judgment enables the recovery system to coordinate with the actual output power of the engine and match the engine status, optimizing overall thermal management.

[0097] S3.1 Entering the high-load waste heat recovery mode, the high-load waste heat recovery module 6 is activated by ECU3 to recover and utilize waste heat while meeting the minimum temperature requirements of post-processing.

[0098] Furthermore, step S3.1 specifically includes:

[0099] Cold start determination value F _cold The value F is equal to 0 and is a high-load judgment value. _high When equal to 1,

[0100] ECU based on exhaust temperature Minimum exhaust temperature allowed at the aftertreatment inlet Calculate the deviation between the control commands of the circulating pump The control command The following relationship must be satisfied:

[0101] ;

[0102] In the formula, This represents the waste heat recovery gain coefficient. The value ranges from 0 to 1;

[0103] ECU3 according to control commands Adjust the speed of the circulating pump and the opening of the three-way valve to continuously regulate the flow rate of the coolant through the heat exchanger as the exhaust temperature changes.

[0104] Understandably, compared to traditional waste heat recovery systems that use on / off or fixed flow control, this invention proposes continuously adjustable flow control. The flow rate is continuously adjusted according to the deviation between the exhaust temperature and the minimum required temperature, achieving refined heat recovery and dynamically matching the exhaust temperature. It always ensures that the exhaust temperature is not lower than the minimum operating temperature of the catalyst, without affecting emission control and guaranteeing after-treatment performance. It also avoids insufficient heat absorption by the coolant due to excessive flow or insufficient recovery due to insufficient flow, thus improving heat recovery efficiency.

[0105] S3.2 Waste heat recovery exit. If the waste heat recovery exit conditions are met, proceed to step S4; otherwise, repeat step S3.1.

[0106] Furthermore, step S3.2 specifically includes:

[0107] During the continuous high-load waste heat recovery mode, when the engine load is less than or equal to the high-load shutdown threshold load... _high_off Or exhaust temperature Less than or equal to the waste heat utilization temperature threshold Subtract the high-load temperature hysteresis ΔT _hr When, then F _high Set the value back to 0. If the condition for exiting waste heat recovery is met, proceed to step S4; otherwise, repeat step S3.1.

[0108] Understandably, to avoid premature termination or continuous ineffective operation of waste heat recovery, this invention introduces load and temperature hysteresis judgment. When the load shutdown threshold is lower than the opening threshold, temperature hysteresis is introduced to improve system stability and prevent frequent switching of operating conditions. When the exhaust temperature decreases or the load is insufficient, it will be shut down in time to avoid ineffective operation of the circulation pump and valves, thus saving energy. It adapts to dynamic operating conditions such as vehicle acceleration, deceleration, and climbing, and realizes intelligent start-stop by adapting to the actual road conditions.

[0109] S4. Enter normal heat preservation mode;

[0110] In this process, ECU3 continuously collects the differential pressure signal from differential pressure sensor 2 under various operating conditions and correlates differential pressure changes, engine speed n, and engine load. When the differential pressure change amplitude exceeds the preset differential pressure threshold and does not match the characteristics of normal operating conditions, it is determined that the vacuum stainless steel insulation shell 103 has leaked or failed in vacuum. ECU3 outputs a control command to the audible and visual warning device 4 to trigger an audible and visual alarm, and at the same time shuts down the cold start automatic heating module 5 and the high load waste heat recovery module 6, retaining only the basic exhaust function of the exhaust passage.

[0111] Understandably, traditional exhaust pipe insulation devices lack intelligent control. This invention proposes a full-condition adaptive control strategy. Based on signals such as temperature, speed, and load, the system automatically judges the operating condition and executes corresponding control, achieving automatic switching between multiple operating conditions without manual intervention. When the pressure difference is abnormal, the system can trigger an alarm and switch to a safe mode to avoid vacuum failure leading to decreased insulation performance or overheating risks. During cold starts, heating accelerates catalytic converter ignition, and waste heat is recovered during high loads. Under normal operating conditions, the temperature is maintained solely by the vacuum insulation layer, achieving full life-cycle energy consumption optimization while balancing energy saving and emissions.

[0112] It should be noted that, specifically in this embodiment, the differential pressure sensor 2 is connected to the ECU 3, and the ECU 3 is connected to the audible and visual warning device 4. The audible and visual warning device 4 provides a failure audible and visual warning, and the process is as follows:

[0113] Initially, it is determined whether exhaust gas is discharged from the exhaust pipe 1 and enters the catalytic converter through the exhaust pipe 1. If engine exhaust gas passes through the exhaust pipe 1 and the exhaust volume flow rate is greater than a certain value, proceed to the next step; otherwise, it is determined that no exhaust gas is discharged from the engine, and the engine is started by controlling the ECU 3 until the exhaust volume flow rate is greater than a certain value, then proceed to the next step.

[0114] Initiate a leak detection process to measure the amplitude of the pressure difference change inside and outside the vacuum stainless steel insulation shell 103.

[0115] When the differential pressure change exceeds the preset differential pressure threshold and does not match the characteristics of normal operating conditions (when the differential pressure signal of the differential pressure sensor 2 changes significantly, that is, the signal voltage increases with the increase of speed, the upstream air pressure is high, the downstream air pressure is low, and a differential pressure is generated), it is determined that the vacuum stainless steel insulation shell 103 has leaked or failed in vacuum. The ECU 3 outputs a control command to the audible and visual warning device 4 to trigger the audible and visual alarm, and at the same time shuts down the cold start automatic heating module 5 and the high load waste heat recovery module 6, retaining only the basic exhaust function of the exhaust channel; when the differential pressure change does not exceed the preset differential pressure threshold and matches the characteristics of normal operating conditions, it is determined that the vacuum stainless steel insulation shell 103 is working normally and has good sealing performance.

[0116] It should be noted that, in order to simplify the control logic, the mode variable Mode is defined in Embodiment 2 of the present invention: Mode=0 represents normal heat preservation mode, Mode=1 represents cold start automatic heating mode, and Mode=2 represents high load waste heat recovery mode.

[0117] The selection rule for Mode is: when F _cold When F = 1, let Mode = 1; when F _cold =0 and F _high When F = 1, let Mode = 2; when F _cold =0 and F _high When Mode = 0, set Mode = 0; the ECU3 updates Mode according to the above rules in each control cycle, and outputs when Mode = 1. Control the operation of the cold start automatic heating module 5, and output when Mode=2. The circulating pump 62 and the three-way valve 61 are controlled to work. When Mode=0, the cold start automatic heating module 5 and the high load waste heat recovery module 6 are turned off, and exhaust heat preservation is achieved solely by the exhaust pipe 1.

[0118] In summary, the integrated vacuum layered thermal insulation exhaust pipe thermal management control system and its control method in the above embodiments of the present invention can minimize the drop in exhaust temperature by utilizing the S-shaped bend of the exhaust pipe and the double-layer thermal insulation effect of the insulation sleeve and the vacuum stainless steel insulation shell. This allows the exhaust gas to enter the aftertreatment device at a higher temperature, increasing the exhaust temperature at the inlet of the exhaust aftertreatment device, improving thermal management performance and aftertreatment catalytic conversion efficiency, and effectively reducing exhaust pollutant emissions. Simultaneously, the double-layer thermal insulation of the insulation sleeve and the vacuum stainless steel insulation shell reduces the transfer of high temperature along the pipe wall to the passenger compartment, achieving engine exhaust insulation and passenger compartment insulation, improving driving and riding comfort. The dynamic failure status of the vacuum stainless steel insulation shell is monitored by a differential pressure sensor. Leak detection is implemented, and an audible and visual alarm is triggered upon detection of a leak. An automatic cold-start heating module is incorporated, with the ECU determining the cold-start condition based on coolant temperature, exhaust temperature, and engine load. The heating power is adjusted according to a preset formula to rapidly raise the exhaust temperature to the optimal operating range for aftertreatment while ensuring safety, thus shortening the time for emissions to exceed limits during cold starts and improving emission control during this phase. A high-load waste heat recovery module is also included, using a high-load determination formula based on load and exhaust temperature to control the amount of waste heat recovered. This recovers some heat from the high-temperature exhaust while meeting the minimum temperature requirements of aftertreatment. This waste heat can be introduced into the engine coolant circuit or the vehicle's heating system, improving overall vehicle thermal efficiency and achieving a balance between energy saving and emission control.

[0119] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0120] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An integrated vacuum layered insulation exhaust pipe thermal management control system, characterized in that, include: An exhaust pipe connected to the engine and in an S-shape, the exhaust pipe including an inner exhaust pipe, an insulation sleeve covering the outside of the inner exhaust pipe, and a vacuum stainless steel insulation shell that encapsulates the insulation sleeve as a whole. A differential pressure sensor is installed on the vacuum stainless steel insulation shell to monitor the pressure difference between the inside and outside of the vacuum stainless steel insulation shell; A cold start automatic heating module is installed inside the exhaust pipe and arranged in the front section of the exhaust passage of the exhaust pipe. A high-load waste heat recovery module is connected to the outer wall of the vacuum stainless steel insulated shell for heat exchange. The ECU and an audible and visual warning device electrically connected to the ECU for issuing an audible and visual warning when the pressure difference is abnormal, the ECU is also connected to the pressure difference sensor, the cold start automatic heating module, the high-load waste heat recovery module, and a device for collecting exhaust temperature. Electrical connection of the exhaust temperature sensor; The ECU determines cold start and high load conditions based on preset operating condition thresholds. In cold start conditions, it controls the automatic cold start heating module to work. In high load conditions, it controls the high load waste heat recovery module to work. In non-cold start and non-high load conditions, it shuts down the automatic cold start heating module and the high load waste heat recovery module, relying solely on the exhaust pipe to achieve exhaust heat preservation. This constitutes an exhaust pipe thermal management system suitable for all operating conditions, including cold start, normal, and high load. The automatic cold start heating module is an electric heating element, which is connected to the vehicle's high-voltage power supply. The ECU controls the heating power by adjusting the pulse width modulation duty cycle of the automatic cold start heating module. The high-load waste heat recovery module includes a three-way valve whose input end is connected to the engine outlet and electrically connected to the ECU. The first output end of the three-way valve is connected to the engine return outlet through a waste heat recovery branch. A circulation pump electrically connected to the ECU and a heat exchanger located on the outside of the vacuum stainless steel insulation shell are sequentially arranged on the waste heat recovery branch. The second output end of the three-way valve is connected to the engine return outlet through a normal heat dissipation branch. A radiator is arranged on the normal heat dissipation branch. The ECU adjusts the flow rate of coolant flowing through the heat exchanger by adjusting the speed of the circulation pump and the opening of the three-way valve, thereby adjusting the amount of waste heat recovery.

2. A control method for the integrated vacuum layered insulation exhaust pipe thermal management control system as described in claim 1, characterized in that, The control method includes: S1. Engine starts, and the ECU controls the exhaust temperature sensor to collect the exhaust temperature. Engine coolant temperature is collected via ECU. Engine speed n and engine load Load provide input signals for subsequent operating condition determination and control output; S2. Cold start condition determination: If the cold start condition is met, proceed to step S2.1; if the cold start condition is not met, proceed to step S3. S2.1 Entering the cold start automatic heating mode, the ECU activates the cold start automatic heating module and determines the heating power based on the deviation between the exhaust temperature and the target temperature, so that the exhaust temperature rises to the target range; S2.2 Cold start heating exit: If the cold start heating exit condition is met, proceed to step S4; otherwise, repeat step S2.

1. S3. High load condition determination: If the conditions for high load condition are met, proceed to step S3.1; if the conditions for high load condition determination are not met, proceed to step S4. S3.1 Entering high-load waste heat recovery mode, the high-load waste heat recovery module is activated by the ECU to recover and utilize waste heat while meeting the minimum temperature requirements of post-processing. S3.2 Waste heat recovery exit. If the waste heat recovery exit conditions are met, proceed to step S4; otherwise, repeat step S3.

1. S4. Enter normal heat preservation mode; The ECU continuously collects the differential pressure signal from the differential pressure sensor under various operating conditions and correlates the differential pressure change, engine speed n, and engine load. When the differential pressure change amplitude exceeds the preset differential pressure threshold and does not match the characteristics of normal operating conditions, it is determined that the vacuum stainless steel insulation shell is leaking or the vacuum has failed. The ECU outputs a control command to the audible and visual warning device to trigger the audible and visual alarm, and at the same time shuts down the cold start automatic heating module and the high load waste heat recovery module, retaining only the basic exhaust function of the exhaust channel. Specifically, step S2 includes: For cold start condition determination, the ECU uses the following relationship to determine whether the cold start condition is met: When the engine coolant temperature Less than or equal to the cold start temperature threshold If the engine speed n is less than or equal to the cold start speed limit threshold n_cold_th and the engine load Load is less than or equal to the cold start load limit threshold Load_cold_th, then the cold start judgment value F_cold is set to 1, and the judgment condition meets the cold start condition and proceeds to step S2.1; otherwise, the cold start judgment value F_cold is set to 0, and the judgment condition does not meet the cold start condition and proceeds to step S3. Specifically, step S2.1 includes: When the cold start determination value F_cold equals 1, the ECU determines the start time based on the exhaust temperature. and the target temperature of the post-processing inlet The deviation between the target heating power of the cold start automatic heating module is calculated. The target heating power The following relationship must be satisfied: In the formula, This is the heating gain coefficient. This represents the maximum output power of the automatic heating module during cold start. The ECU determines the target heating power of the automatic heating module based on the cold start requirements. Generate electric heating duty cycle control commands to automatically heat the exhaust gas, raising the exhaust temperature to the target range; Specifically, step S2.2 includes: During the continuous cold start self-heating mode, when the engine coolant temperature... Greater than or equal to the cold start temperature threshold Add the cold start temperature hysteresis ΔT_cold or the cold start timing t being greater than or equal to the maximum cold start duration. If the condition is met, the cold start judgment value F_cold is reset to 0, and the cold start heating exit condition is met, proceeding to step S4; otherwise, step S2.1 is executed again. Specifically, step S3 includes: To determine whether normal operating conditions are met under high load conditions, the ECU uses the following relationship: When the engine load is greater than or equal to the high load activation threshold Load_high_on, and the exhaust temperature... Greater than or equal to the waste heat utilization temperature threshold If the condition is met, the high load judgment value F_high is set to 1, and the judgment condition is satisfied, proceeding to step S3.1; otherwise, the high load judgment value F_high is set to 0, and the judgment condition is not satisfied, proceeding to step S4. Specifically, step S3.1 includes: When the cold start determination value F_cold equals 0 and the high load determination value F_high equals 1. ECU based on exhaust temperature Minimum exhaust temperature allowed at the aftertreatment inlet Calculate the deviation between the control commands of the circulating pump The control command The following relationship must be satisfied: ； In the formula, This represents the waste heat recovery gain coefficient. The value ranges from 0 to 1; ECU according to control commands Adjust the speed of the circulating pump and the opening of the three-way valve to continuously regulate the flow rate of the coolant through the heat exchanger as the exhaust temperature changes; Specifically, step S3.2 includes: During the continuous high-load waste heat recovery mode, when the engine load is less than or equal to the high-load shutdown threshold Load_high_off, or the exhaust temperature... Less than or equal to the waste heat utilization temperature threshold If the high-load temperature hysteresis ΔT_hr is subtracted, F_high is reset to 0. If the condition is met, the waste heat recovery exit condition is met and the process proceeds to step S4; otherwise, step S3.1 is executed again.

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