Control system and control method based on 48V electric heating aftertreatment

Abstract

The invention discloses a control system based on 48V electric heating post-processing, and relates to a post-processing technology, and a 48V electric heater is installed in a post-processing system; according to the SCR temperature and a set temperature threshold interval, a 48V electric heater is controlled to heat the tail gas, so that the NOx conversion efficiency is larger than or equal to set target efficiency; when the SCR temperature is smaller than the minimum threshold value in the temperature threshold value interval, the 48V electric heater is controlled to work at rated heating power; when the SCR temperature is within the temperature threshold interval, the heating power of the 48V electric heater is dynamically controlled according to the NOx conversion efficiency; and when the SCR temperature is larger than the maximum threshold value in the temperature threshold value interval, the 48V electric heater is controlled to stop working. The invention further discloses a control method based on 48V electric heating aftertreatment. Compared with a traditional 12V or 24V electric heating system, the 48V voltage system can provide higher power output, and the requirement of a post-processing system for rapid heating during cold start or low-load operation can be rapidly met.

Description

Technical Field

[0001] The present invention relates to post-processing technology, and more particularly, to a control system and a control method based on 48V electric heating post-processing. Background Art

[0002] In the commercial vehicle sector, current after-treatment electric heating systems mostly utilize 24V heating systems. Under conditions where after-treatment requires rapid exhaust gas heating, the heaters must quickly ramp up to kilowatts or even several kilowatts of power, posing significant challenges to the heating system's rapid and stable output. Traditional 24V heating systems, on the other hand, suffer from a long heating time, resulting in a certain lag in heating and negatively impacting emissions. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the shortcomings of the existing technology and provide a control system and control method based on 48V electric heating after-treatment. Compared with traditional 12V or 24V electric heating systems, the 48V voltage system can provide higher power output and can quickly meet the after-treatment system's demand for rapid heating during cold start or low-load operation.

[0004] The present invention discloses a control method for 48V electric heating aftertreatment, which includes installing a 48V electric heater in the aftertreatment system; obtaining the SCR temperature and NOx conversion efficiency, and controlling the 48V electric heater to heat the exhaust gas based on the SCR temperature and a set temperature threshold range, so that the NOx conversion efficiency is greater than or equal to a set target efficiency;

[0005] When the SCR temperature is lower than a minimum threshold value in the temperature threshold range, controlling the 48V electric heater to operate at a rated heating power;

[0006] When the SCR temperature is within a temperature threshold range, dynamically controlling the heating power of the 48V electric heater according to the NOx conversion efficiency;

[0007] When the SCR temperature is greater than a maximum threshold in a temperature threshold range, the 48V electric heater is controlled to stop working.

[0008] Preferably, the heating power of the 48V electric heater is dynamically controlled, and the specific control method is:

[0009] Determine the relationship between the NOx conversion efficiency and the set target efficiency; if the NOx conversion efficiency is greater than or equal to the target efficiency, control the heating power of the 48V electric heater to maintain the NOx conversion efficiency; if the NOx conversion efficiency is less than the target efficiency, close-loop control the electric heating power of the 48V electric heater based on the difference between the NOx conversion efficiency and the target efficiency.

[0010] Preferably, when the 48V electric heater is started, the heating power required by the 48V electric heater is controlled and outputted through a 48V power supply control strategy.

[0011] Preferably, the 48V power supply control strategy is specifically as follows:

[0012] The voltage of the 24V battery that powers the engine controller is collected and compared with a first voltage threshold. If the voltage of the 24V battery is less than the first voltage threshold, the 48V electric heater is prohibited from starting; if the voltage of the 24V battery is greater than or equal to the first voltage threshold, the 48V system power supply mechanism is executed.

[0013] Preferably, the 48V system power supply mechanism is specifically as follows:

[0014] Collect the power of the 48V battery in the 48V system;

[0015] When the power level of the 48V battery is less than a set first power threshold, the 48V generator is started, and it is determined whether the heating power required by the 48V electric heater is greater than the output power of the 48V generator; if so, all the output power of the 48V generator is delivered to the 48V electric heater; otherwise, after the output power of the 48V generator meets the heating power required by the 48V electric heater, the remaining power is used to charge the 48V battery;

[0016] When the power level of the 48V battery is between a first power threshold and a second power threshold, the 48V generator is started, and it is determined whether the heating power required by the 48V electric heater is greater than the output power of the 48V generator; if so, all the output power of the 48V generator is delivered to the 48V electric heater, and at the same time, the 48V battery supplies the remaining portion of the heating power required by the 48V electric heater that cannot be met by the 48V generator; otherwise, after the output power of the 48V generator meets the heating power required by the 48V electric heater, the remaining portion is used to charge the 48V battery;

[0017] When the power level of the 48V battery is greater than a second power threshold, the 48V generator is started, and it is determined whether the heating power required by the 48V electric heater is greater than the output power of the 48V generator; if so, all the output power of the 48V generator is delivered to the 48V electric heater, and at the same time, the 48V battery supplies the remaining part of the heating power required by the 48V electric heater that cannot be met by the 48V generator; otherwise, after the output power of the 48V generator meets the heating power required by the 48V electric heater, the remaining part is used to charge the 24V battery.

[0018] Preferably, if the voltage of the 24V battery is less than a first voltage threshold, the 48V generator is started to charge the 24V battery.

[0019] A control system based on 48V electric heating aftertreatment includes a 48V electric heater, a 48V battery, a 48V generator, a 24V battery and an ECU; the 48V electric heater is installed in the aftertreatment system, the 48V generator is electrically connected to the 48V electric heater and the 48V battery through a 48V battery management system, the 48V generator and the 48V battery are electrically connected to the 24V battery through a DC-DC driver, and the ECU uses the control method to control the 48V electric heater to heat exhaust gas so that the NOx conversion efficiency is greater than or equal to a set target efficiency.

[0020] Beneficial effects

[0021] The advantages of the present invention are:

[0022] The 1.48V electric heating system is highly integrated with the aftertreatment system, with the 48V heater installed directly inside the catalytic converter. This effectively reduces heat loss during heat transfer and significantly improves heating efficiency. Compared to traditional 12V or 24V electric heating systems, the 48V system offers higher power output, quickly meeting the aftertreatment system's demand for rapid heating during cold starts or low-load operation. Furthermore, through the rational layout of the electric heating elements and related circuitry, the system achieves better installation adaptability within the vehicle's limited space, minimizing interference with other vehicle components.

[0023] 2. The control algorithm adopted by the present invention ensures that the after-treatment system always operates within the optimal temperature range by real-time monitoring of the key temperatures and NOx conversion efficiency of the after-treatment system, combined with dynamic adjustment of the electric heating power, while also reducing unnecessary energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the control method flow of the present invention;

[0025] Figure 2This is a flow chart of the 48V power supply control strategy of the present invention;

[0026] Figure 3 This is a schematic diagram of the closed-loop control process of electric heating power based on NOx efficiency deviation of the present invention;

[0027] Figure 4 This is a 48V electric heating post-processing configuration diagram of the present invention;

[0028] Figure 5 It is a schematic diagram of the control system structure of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the embodiments, but this does not constitute any limitation to the present invention. Any limited number of modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0030] Example 1

[0031] See Figure 1-Figure 2 The present invention discloses a control method based on 48V electric heating aftertreatment, in which a 48V electric heater is installed in the aftertreatment system. The SCR temperature and NOx conversion efficiency are obtained. The SCR temperature is (T8+T9) / 2 in the aftertreatment system, where T8 is the upstream temperature of the Lo-SCR and T9 is the downstream temperature of the Lo-SCR. The 48V electric heater is controlled to heat the exhaust gas based on the SCR temperature and a set temperature threshold range, so that the NOx conversion efficiency is greater than or equal to the set target efficiency. Compared with traditional 12V or 24V electric heating systems, the 48V voltage system can provide higher power output and can quickly meet the aftertreatment system's demand for rapid heating during cold starts or low-load operation. Furthermore, in terms of control strategy, the system makes a comprehensive judgment based on multiple parameters, including the engine's exhaust temperature and NOx conversion efficiency, to intelligently control the start and stop of the electric heating system and its power output. During a cold start of the engine, the system can quickly activate the electric heater, allowing the aftertreatment system to quickly reach operating temperature, thereby significantly reducing pollutant emissions during the cold start phase.

[0032] In this embodiment, when the SCR temperature is lower than the minimum threshold value T1 in the temperature threshold range, the 48V electric heater is controlled to operate at the rated heating power to provide sufficient heat to ensure that the SCR system can quickly reach the SCR high-efficiency operating temperature, thereby avoiding low catalytic efficiency and substandard emissions due to excessively low temperature.

[0033] When the SCR temperature is within the temperature threshold range, the heating power of the 48V electric heater is dynamically controlled according to the NOx conversion efficiency. The specific control method for dynamically controlling the heating power of the 48V electric heater is as follows:

[0034] Determine the relationship between the NOx conversion efficiency and the set target efficiency. If the NOx conversion efficiency is greater than or equal to the target efficiency, control the heating power of the 48V electric heater to maintain the current NOx conversion efficiency. This can minimize energy consumption while ensuring emission requirements. Specifically, the 48V electric heater can be calibrated according to the corresponding relationship in Table 1:

[0035] NOx conversion efficiency 90％ 95％ 96％ 98％ 99％ Electric heating power 3kW 3kW 1.5kW 1kW 0.5kW

[0036] Table 1: Minimum maintenance electric heating power based on conversion efficiency

[0037] If the NOx conversion efficiency is lower than the target efficiency, the electric heating power of the 48V electric heater is closed-loop controlled based on the difference between the NOx conversion efficiency and the target efficiency. That is, the 48V electric heating power is dynamically adjusted according to the gap between the actual conversion efficiency and the target conversion efficiency, so as to achieve the target conversion efficiency as soon as possible and ensure that emissions meet the limit requirements.

[0038] As shown in Table 2 below, the target efficiency obtained from Table 2 is calculated by difference with the measured NOx efficiency, and the electric heating power is calculated in a closed loop based on the efficiency difference.

[0039]

[0040] Table 2: NOx target conversion efficiency (SCR temperature °C / exhaust flow kg / h)

[0041] Specifically, when the SCR temperature is within the temperature threshold range and the measured NOx efficiency E1 is less than the target efficiency E, the NOx conversion target efficiency E is obtained based on the temperature and exhaust flow in Table 1. The measured NOx efficiency E1 = (front stage NOx concentration - rear stage NOx concentration) / front stage NOx concentration, and the efficiency deviation e(t) = target efficiency E - measured NOx efficiency E1. Based on the efficiency deviation, the PID closed-loop control of the 48V electric heating power is performed, specifically according to Figure 3 The control logic of Figure 3 The control logic shown is the prior art in this field and will not be further expanded / discussed in this article.

[0042] When the SCR temperature is greater than the maximum threshold T2 in the temperature threshold range, the 48V electric heater is controlled to stop working. At this time, the system believes that the temperature is high enough and no additional heating is required, so as to save power and reduce fuel consumption.

[0043] The entire 48V exhaust electric heater power control system is a closed-loop control system that comprehensively considers SCR temperature and NOx conversion efficiency. By monitoring these two key parameters in real time and dynamically adjusting the electric heater power based on preset thresholds and logical relationships, it achieves the goals of meeting emission requirements (ensuring efficient NOx conversion) while also balancing energy conservation and safe system operation.

[0044] Commercial vehicles generally use 24V batteries, while the electric heater of the present invention uses a 48V voltage. Therefore, in order to ensure the normal start-up of the 48V electric heater, the present invention controls the output of the heating power required by the 48V electric heater through a 48V power supply control strategy, thereby achieving the purpose of reasonably allocating the charging power of the intelligent generator and the discharging power of the heater, ensuring that the battery power is within a reasonable range, and avoiding overcharging or over-discharging of the battery.

[0045] In this embodiment, the 48V power supply control strategy is specifically as follows:

[0046] The voltage of the 24V battery that powers the engine controller is collected and compared with a first voltage threshold, U1. If the 24V battery voltage is less than U1, the 48V electric heater is disabled and the 48V generator is activated to charge the 24V battery. This means that if the 24V battery is low, ensuring normal engine operation and protecting the battery take priority. If the 24V battery voltage is greater than or equal to U1, the 48V system power supply mechanism is activated to ensure stable power supply to the 48V electric heater.

[0047] The 48V system power supply mechanism of this embodiment is specifically as follows: collecting the power of the 48V battery in the 48V system;

[0048] When the power level of the 48V battery is less than a set first power threshold a1, the 48V generator is started and a determination is made as to whether the heating power P1 required by the 48V electric heater is greater than the output power P2 of the 48V generator. If so, all of the output power P2 of the 48V generator is delivered to the 48V electric heater. Otherwise, after the output power P2 of the 48V generator meets the heating power P1 required by the 48V electric heater, the remaining power is used to charge the 48V battery.

[0049] When the charge level of the 48V battery is between a first charge threshold a1 and a second charge threshold a2, the 48V generator is started, and it is determined whether the heating power P1 required by the 48V electric heater is greater than the output power P2 of the 48V generator. If so, all of the output power P2 of the 48V generator is delivered to the 48V electric heater, and the 48V battery supplies the remaining portion of the heating power P1 required by the 48V electric heater that cannot be met by the 48V generator. Otherwise, after the output power P2 of the 48V generator meets the heating power P1 required by the 48V electric heater, the remaining portion is used to charge the 48V battery.

[0050] When the power level of the 48V battery is greater than the second power threshold a2, the 48V generator is started, and it is determined whether the heating power P1 required by the 48V electric heater is greater than the output power P2 of the 48V generator; if so, the output power P2 of the 48V generator is fully delivered to the 48V electric heater, and at the same time, the 48V battery supplies the remaining part of the heating power P1 required by the 48V electric heater that cannot be satisfied by the 48V generator; otherwise, after the output power P2 of the 48V generator satisfies the heating power P1 required by the 48V electric heater, the remaining part is used to charge the 24V battery.

[0051] Through the above control strategy, the system can quickly start electric heating, allowing the after-treatment system to quickly reach operating temperature, thereby significantly reducing pollutant emissions during the cold start phase. The system can also reduce unnecessary electricity consumption and improve energy utilization.

[0052] Example 2

[0053] like Figure 4 and Figure 5 As shown, a control system based on 48V electric heating aftertreatment includes a 48V electric heater, a 48V battery, a 48V generator, a 24V battery and an ECU.

[0054] Among them, the 48V battery provides power to the 48V electric heating system. When the 48V electric heating requires high power, the 48V battery can work with the generator to supplement additional power for the 48V electric heating.

[0055] 24V battery: provides power for engine starting and electrical equipment of the vehicle.

[0056] 48V generator: During vehicle operation, the engine generates electricity to charge the 48V battery, maintain battery power, ensure continuous and stable operation of the system, and convert the 48V voltage into 24V through DC-DC to charge the 24V battery.

[0057] MOS OrRelay: A power device used to control the on / off flow of current to the electric heater from the generator and 48V battery. By controlling the on / off state of the device, precise control of the heater's power supply is achieved.

[0058] The 48V heater is the system's core component, converting electrical energy into heat to heat the aftertreatment system to meet stringent emissions requirements. Installed inside the catalytic converter, it effectively reduces heat loss during transfer and significantly improves heating efficiency.

[0059] ECU (Electronic Control Unit): As the brain of the system, it is responsible for receiving various sensor signals, such as temperature sensors, and applying the above control method to control the 48V electric heater to heat the exhaust gas so that the NOx conversion efficiency is greater than or equal to the set target efficiency.

[0060] The DC-DC driver, specifically the DCDC2500, is a DC-DC converter that converts 48V voltage into 24V or 24V into 48V to meet the power supply requirements of different electrical devices.

[0061] 48V BMS (48V Battery Management System): Monitors and manages 48V batteries, including monitoring battery voltage, current, temperature and other parameters to ensure that the battery operates in a safe and reliable state, while controlling and protecting the battery's charging and discharging process.

[0062] CAN bus: used to connect communication signal transmission and communication functions.

[0063] The 48V electric heating system of the present invention can raise the temperature of the after-treatment system to the temperature required for the catalytic reaction in a short period of time. For example, the exhaust pipe temperature can be raised to the operating temperature for efficient conversion of the catalyst within 2-3 minutes. Even in low-temperature environments, the system can ensure the normal operation of the after-treatment system and significantly improve the emission performance of the vehicle in harsh environments. By precisely controlling the heating temperature, the system can also increase the temperature of the diesel particulate filter (DPF), enhance the passive regeneration capability, reduce the frequency of active regeneration, and avoid damage to the catalyst due to excessively high regeneration temperature, thereby extending the service life of the catalyst.

[0064] In terms of system integration, the 48V electric heating system seamlessly integrates with the vehicle's existing electrical system, eliminating the need for major changes to the vehicle's electrical architecture and reducing integration complexity and cost. Furthermore, the system is not only suitable for Selective Catalytic Reduction (SCR) systems but can also be used in conjunction with other after-treatment technologies, such as three-way catalytic converters (TWCs), demonstrating its broad applicability.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention. These modifications and improvements will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A control method based on 48V electric heating post-processing, characterized in that: Installing a 48V electric heater in the post-treatment system; obtaining an SCR temperature and a NOx conversion efficiency, and controlling the 48V electric heater to heat the exhaust gas based on the SCR temperature and a set temperature threshold range so that the NOx conversion efficiency is greater than or equal to a set target efficiency; When the SCR temperature is lower than a minimum threshold value in the temperature threshold range, controlling the 48V electric heater to operate at a rated heating power; When the SCR temperature is within a temperature threshold range, dynamically controlling the heating power of the 48V electric heater according to the NOx conversion efficiency; When the SCR temperature is greater than a maximum threshold in a temperature threshold range, the 48V electric heater is controlled to stop working.

2. The control method based on 48V electric heating post-processing according to claim 1 is characterized in that: The heating power of the 48V electric heater is dynamically controlled. The specific control method is as follows: Determine the relationship between the NOx conversion efficiency and the set target efficiency; if the NOx conversion efficiency is greater than or equal to the target efficiency, control the heating power of the 48V electric heater to maintain the NOx conversion efficiency; if the NOx conversion efficiency is less than the target efficiency, close-loop control the electric heating power of the 48V electric heater based on the difference between the NOx conversion efficiency and the target efficiency.

3. A control method based on 48V electric heating post-processing according to claim 1 or 2, characterized in that: When the 48V electric heater is started, the heating power required by the 48V electric heater is controlled and outputted through the 48V power supply control strategy.

4. The control method based on 48V electric heating post-processing according to claim 3 is characterized in that: The 48V power supply control strategy is specifically as follows: The voltage of the 24V battery that powers the engine controller is collected and compared with a first voltage threshold. If the voltage of the 24V battery is less than the first voltage threshold, the 48V electric heater is prohibited from starting; if the voltage of the 24V battery is greater than or equal to the first voltage threshold, the 48V system power supply mechanism is executed.

5. The control method based on 48V electric heating post-processing according to claim 4 is characterized in that: The 48V system power supply mechanism is specifically as follows: Collect the power of the 48V battery in the 48V system; When the power level of the 48V battery is less than a set first power threshold, the 48V generator is started, and it is determined whether the heating power required by the 48V electric heater is greater than the output power of the 48V generator; if so, all the output power of the 48V generator is delivered to the 48V electric heater; otherwise, after the output power of the 48V generator meets the heating power required by the 48V electric heater, the remaining power is used to charge the 48V battery; When the power level of the 48V battery is between a first power threshold and a second power threshold, the 48V generator is started, and it is determined whether the heating power required by the 48V electric heater is greater than the output power of the 48V generator; if so, all the output power of the 48V generator is delivered to the 48V electric heater, and at the same time, the 48V battery supplies the remaining portion of the heating power required by the 48V electric heater that cannot be met by the 48V generator; otherwise, after the output power of the 48V generator meets the heating power required by the 48V electric heater, the remaining portion is used to charge the 48V battery; When the power level of the 48V battery is greater than a second power threshold, the 48V generator is started, and it is determined whether the heating power required by the 48V electric heater is greater than the output power of the 48V generator; if so, all the output power of the 48V generator is delivered to the 48V electric heater, and at the same time, the 48V battery supplies the remaining part of the heating power required by the 48V electric heater that cannot be met by the 48V generator; otherwise, after the output power of the 48V generator meets the heating power required by the 48V electric heater, the remaining part is used to charge the 24V battery.

6. The control method based on 48V electric heating post-processing according to claim 4 is characterized in that: If the voltage of the 24V battery is less than a first voltage threshold, the 48V generator is started to charge the 24V battery.

7. A control system based on 48V electric heating post-processing, characterized in that, It includes a 48V electric heater, a 48V battery, a 48V generator, a 24V battery and an ECU; the 48V electric heater is installed in the after-treatment system, the 48V generator is electrically connected to the 48V electric heater and the 48V battery at the same time through a 48V battery management system, the 48V generator and the 48V battery are electrically connected to the 24V battery at the same time through a DC-DC driver, and the ECU uses the control method described in any one of claims 1 to 6 to control the 48V electric heater to heat the exhaust gas so that the NOx conversion efficiency is greater than or equal to the set target efficiency.

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