Exhaust heat management system and control method, engine exhaust system, and vehicle

Abstract

The application discloses an exhaust heat management system and a control method, an engine exhaust system and a vehicle, and relates to the field of engines.The exhaust heat management system comprises an exhaust cooling device, an exhaust heating device, a first temperature acquisition device and a controller.When it is determined that the original exhaust temperature is out of the high-efficiency temperature range of the catalyst, the controller determines an exhaust temperature adjustment strategy according to the size relationship between the original exhaust temperature and the upper limit temperature threshold and the lower limit temperature threshold of the high-efficiency temperature range, determines the target heat required for adjusting the original exhaust temperature to the high-efficiency temperature range based on the current exhaust mass flow of the hydrogen engine, and controls the exhaust cooling device or the exhaust heating device enabled in the exhaust temperature adjustment strategy based on the target heat.The original exhaust temperature is heated or cooled, so that the exhaust temperature entering the aftertreatment system is always maintained in the high-efficiency temperature range of the catalyst.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and more specifically, to an exhaust thermal management system and control method, an engine exhaust system, and a vehicle. Background Technology

[0002] A hydrogen engine is an engine that uses hydrogen as fuel. To improve thermal efficiency and reduce humidity, hydrogen engines often employ a lean-burn combustion method with a larger air volume. Therefore, the heat generated by hydrogen combustion is dispersed and diluted by the extremely high airflow, resulting in a lower combustion temperature and lower nitrogen oxide emissions compared to diesel engines. However, to meet stringent emission regulations, an aftertreatment system is still required after the hydrogen engine to treat the nitrogen oxides in its exhaust.

[0003] Currently, the aftertreatment system of a hydrogen engine is typically located downstream of the hydrogen engine. (Selective Catalytic Reduction) post-treatment system. Post-processing system The catalyst undergoes a redox reaction with the nitrogen oxides produced by the combustion in the hydrogen engine, converting them into non-toxic water and nitrogen. However, The catalyst exhibits high activity within a narrow temperature range, see [reference needed]. Figure 1 shown The efficient temperature range of catalysts is typically concentrated around 200℃; outside this efficient temperature range, such as... Figure 1 shown Catalysts are not in their high-efficiency temperature range. The activity of the catalyst will be significantly affected.

[0004] Therefore, how to maintain the exhaust temperature of a hydrogen engine at... Finding the optimal temperature range for catalysts has become a critical technical challenge for those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention discloses an exhaust thermal management system and control method, an engine exhaust system, and a vehicle, so as to maintain the exhaust temperature of a hydrogen engine at a certain level. Within the high-efficiency temperature range of the catalyst.

[0006] An exhaust thermal management system includes: an exhaust cooling device, an exhaust heating device, a first temperature acquisition device, and a controller;

[0007] Both the exhaust cooling device and the exhaust heating device are installed in the hydrogen engine and... On the exhaust pipes between the aftertreatment systems;

[0008] The first temperature collection device is arranged on an exhaust pipe connected to an output end of the hydrogen engine, and is configured to collect an original exhaust temperature of the hydrogen engine.

[0009] The controller is connected to the exhaust cooling device, the exhaust heating device and the first temperature collection device, and is configured to obtain the original exhaust temperature. If the original exhaust temperature is out of a high-efficiency temperature range of the catalyst, an exhaust temperature adjustment strategy is determined according to a size relationship between the original exhaust temperature and upper and lower temperature threshold values of the high-efficiency temperature range, a target heat required for adjusting the original exhaust temperature to the high-efficiency temperature range is determined based on a current exhaust mass flow of the hydrogen engine, and an exhaust cooling device or an exhaust heating device enabled in the exhaust temperature adjustment strategy is controlled based on the target heat.

[0010] Optionally, the exhaust cooling device comprises a water jacket exhaust pipe.

[0011] The water jacket exhaust pipe is sleeved on an exhaust pipe between the hydrogen engine and the aftertreatment system, and is configured to perform cooling treatment on original high-temperature gas discharged by the hydrogen engine through cooling liquid flow.

[0012] Optionally, the exhaust heating device is sleeved on the exhaust pipe between the hydrogen engine and the aftertreatment system, or is arranged inside the exhaust pipe between the hydrogen engine and the aftertreatment system, and is configured to perform heating treatment on original low-temperature gas discharged by the hydrogen engine through heat generated when electric current flows through resistance wires.

[0013] Optionally, the control method further comprises: a second temperature collection device.

[0014] The second temperature collection device is arranged on an exhaust pipe connected to an input end of the aftertreatment system, and is connected to the controller.

[0015] The second temperature collection device is configured to collect an adjusted exhaust temperature of the hydrogen engine.

[0016] The controller is configured to obtain the adjusted exhaust temperature, and stop controlling the enabled exhaust cooling device or the exhaust heating device when determining that the adjusted exhaust temperature is located in the high-efficiency temperature range.

[0017] A control method of an exhaust heat management system, applied to a controller in the exhaust heat management system, and comprising the following steps of:

[0018] ​​​​obtaining an original exhaust temperature of a hydrogen engine;

[0019] if the original exhaust temperature exceeds a high-efficiency temperature range of a catalyst, determining an exhaust temperature adjustment strategy according to a size relationship between the original exhaust temperature and upper and lower temperature threshold values of the high-efficiency temperature range;

[0020] determining a target heat required for adjusting the original exhaust temperature to the high-efficiency temperature range based on a current exhaust mass flow of the hydrogen engine;

[0021] controlling an exhaust cooling device or an exhaust heating device enabled in the exhaust temperature adjustment strategy based on the target heat.

[0022] Optionally, the determining process of the exhaust temperature adjustment strategy comprises:

[0023] if the original exhaust temperature is less than the lower temperature threshold value, the exhaust temperature adjustment strategy is to disable the exhaust cooling device and enable the exhaust heating device;

[0024] or,

[0025] if the original exhaust temperature is greater than the upper temperature threshold value, the exhaust temperature adjustment strategy is to enable the exhaust cooling device and disable the exhaust heating device.

[0026] Optionally, the determining a target heat required for adjusting the original exhaust temperature to the high-efficiency temperature range based on a current exhaust mass flow of the hydrogen engine comprises:

[0027] if the original exhaust temperature is less than the lower temperature threshold value, calculating a first temperature difference value between the lower temperature threshold value and the original exhaust temperature;

[0028] adding the first temperature difference value and a falling temperature corresponding to a heat loss to obtain a first target temperature difference value, wherein the heat loss is a heat loss caused by an exhaust pipe between the hydrogen engine and a post-processing system;

[0029] multiplying the first target temperature difference value, the current exhaust mass flow, an exhaust specific heat capacity, and a heating time to obtain a heating heat required for heating the original low-temperature gas discharged by the hydrogen engine, and determining the heating heat as the target heat.

[0030] Optionally, the controlling an exhaust cooling device or an exhaust heating device enabled in the exhaust temperature adjustment strategy based on the target heat comprises:

[0031] ​determining a heating power of the exhaust heating device according to the target heat and heating time, if the original exhaust temperature is less than the lower temperature threshold value;

[0032] calculating a current flowing through the electrically resistive wire according to the heating power and resistance value of the electrically resistive wire in the exhaust heating device;

[0033] controlling the current flowing through the electrically resistive wire according to the current, so that the electrically resistive wire generates heat to warm up the original low-temperature exhaust gas discharged by the hydrogen engine.

[0034] Optionally, the determining of the target heat required for adjusting the original exhaust temperature to the high-efficiency temperature range based on the current exhaust mass flow of the hydrogen engine comprises:

[0035] calculating a second temperature difference value between the original exhaust temperature and the upper temperature threshold value, if the original exhaust temperature is greater than the upper temperature threshold value;

[0036] subtracting a falling temperature corresponding to heat loss from the second temperature difference value to obtain a second target temperature difference value, wherein the heat loss is heat loss caused by the hydrogen engine and exhaust pipe between the exhaust aftertreatment system;

[0037] multiplying the second target temperature difference value, the current exhaust mass flow, exhaust specific heat capacity and cooling time to obtain cooling heat required for cooling the original high-temperature exhaust gas discharged by the hydrogen engine, and determining the cooling heat as the target heat.

[0038] Optionally, the controlling of the exhaust cooling device or exhaust heating device enabled in the exhaust temperature adjustment strategy based on the target heat comprises:

[0039] calculating a third temperature difference value between the temperature of the cooling liquid flowing out of the exhaust cooling device and the temperature of the cooling liquid flowing into the exhaust cooling device, if the original exhaust temperature is greater than the upper temperature threshold value;

[0040] obtaining a cooling liquid mass flow based on the target heat, the third temperature difference value, cooling liquid specific heat capacity and cooling time;

[0041] controlling the flow size of the cooling liquid according to the cooling liquid mass flow to cool the original high-temperature exhaust gas discharged by the hydrogen engine.

[0042] Optionally, when the exhaust thermal management system further comprises a second temperature acquisition device, after the controlling of the exhaust cooling device or exhaust heating device enabled in the exhaust temperature adjustment strategy based on the target heat, the method further comprises:​

[0043] The second temperature acquisition device is used to acquire the adjusted exhaust temperature of the hydrogen engine. On the exhaust pipe connected to the input end of the aftertreatment system;

[0044] If the adjusted exhaust temperature is within the high-efficiency temperature range, control of the activated exhaust cooling device or exhaust heating device shall be stopped.

[0045] An engine exhaust system includes the exhaust thermal management system described above, and Post-processing system.

[0046] A vehicle comprising: a hydrogen engine, The aftertreatment system and the aforementioned exhaust thermal management system, wherein the exhaust thermal management system is disposed in the hydrogen engine and the... Between post-processing systems.

[0047] As can be seen from the above technical solutions, the present invention discloses an exhaust thermal management system and control method, an engine exhaust system, and a vehicle. The exhaust thermal management system includes: an exhaust cooling device, an exhaust heating device, a first temperature acquisition device, and a controller. Both the exhaust cooling device and the exhaust heating device are installed in the hydrogen engine and... On the exhaust pipe between the aftertreatment systems, a first temperature acquisition device is installed on the exhaust pipe connected to the output end of the hydrogen engine to collect the raw exhaust temperature of the hydrogen engine. The controller determines that the raw exhaust temperature exceeds... When the catalyst operates within its high-efficiency temperature range, an exhaust temperature regulation strategy is determined based on the relationship between the initial exhaust temperature and the upper and lower temperature thresholds of the high-efficiency temperature range. A target heat required to regulate the initial exhaust temperature to the high-efficiency temperature range is determined based on the current exhaust mass flow rate of the hydrogen engine. The exhaust cooling or heating device activated in the exhaust temperature regulation strategy is then controlled based on this target heat. This invention heats the initial low-temperature gas discharged from the hydrogen engine when the initial exhaust temperature is below the lower temperature threshold of the high-efficiency temperature range; and cools the initial high-temperature gas discharged from the hydrogen engine when the initial exhaust temperature is above the upper temperature threshold of the high-efficiency temperature range. Therefore, it ensures that the exhaust gas can enter the high-efficiency temperature range. The exhaust temperature of the aftertreatment system is always maintained at Within the catalyst's highly efficient temperature range, thus enabling... The catalyst maintains high activity during the oxidation-reduction reaction of nitrogen oxides produced by the combustion of hydrogen in the engine. Attached Figure Description

[0048] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced below. Obviously, the accompanying drawings in the following description only aim to explain the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative effort based on the disclosed drawings.

[0049] Figure 1 For A schematic diagram of NOx conversion efficiency in the art;

[0050] Figure 2 A schematic diagram of an exhaust heat management system disclosed in an embodiment of the present application;

[0051] Figure 3 A schematic diagram of a water jacketed exhaust pipe disclosed in an embodiment of the present application;

[0052] Figure 4 A schematic diagram of another exhaust heat management system disclosed in an embodiment of the present application;

[0053] Figure 5 A flow chart of a control method of an exhaust heat management system disclosed in an embodiment of the present application;

[0054] Figure 6 A flow chart of a control method of an exhaust heat management system disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort fall within the scope of protection of the present application.

[0056] The embodiments of the present application disclose an exhaust heat management system and a control method, an engine exhaust system and a vehicle, so as to heat the original low-temperature gas discharged by a hydrogen engine 10 when the original exhaust temperature of the hydrogen engine 10 is lower than the lower limit temperature threshold of the high-efficiency temperature interval; and cool the original high-temperature gas discharged by the hydrogen engine 10 when the original exhaust temperature is higher than the upper limit temperature threshold of the high-efficiency temperature interval, so as to ensure that the exhaust temperature entering the aftertreatment system 20 is always maintained within the high-efficiency temperature interval of the catalyst. The exhaust temperature entering the aftertreatment system 20 is always maintained within the high-efficiency temperature interval of the catalyst. The catalyst always maintains high activity when performing the oxidation-reduction reaction on the nitrogen oxides generated by the hydrogen engine 10. The catalyst always maintains high activity when performing the oxidation-reduction reaction on the nitrogen oxides generated by the hydrogen engine 10.

[0057] Referring to Figure 2 , the embodiment of the present application discloses a schematic diagram of an exhaust heat management system, which comprises an exhaust cooling device 11, an exhaust heating device 12, a first temperature collecting device 13 and a controller 14.

[0058] The exhaust cooling device 11 and the exhaust heating device 12 are both arranged on an exhaust pipe between the hydrogen engine 10 and the aftertreatment system 20.

[0059] The specific arrangement positions of the exhaust cooling device 11 and the exhaust heating device 12 on the exhaust pipe are not limited, for example, as shown in the figure, the exhaust cooling device 11 can be arranged on the exhaust pipe close to the hydrogen engine 10, and the exhaust heating device 12 is arranged on the exhaust pipe close to the Figure 2 aftertreatment system 20. Of course, the arrangement positions of the exhaust cooling device 11 and the exhaust heating device 12 can also be interchanged, that is, the exhaust heating device 12 is arranged on the exhaust pipe close to the hydrogen engine 10, and the exhaust cooling device 11 is arranged on the exhaust pipe close to the aftertreatment system 20.

[0060] In actual application, the exhaust cooling device 11 includes but is not limited to a water jacket exhaust pipe, which is sleeved on the exhaust pipe between the hydrogen engine 10 and the aftertreatment system 20, and the original high-temperature gas discharged by the hydrogen engine 10 is subjected to cooling treatment through the flow of cooling liquid. For details, see the schematic diagram of the water jacket exhaust pipe shown in the figure, the central position 111 of the water jacket exhaust pipe is used for wrapping the exhaust pipe, and the outer part 112 is used for the flow of cooling liquid, so as to implement the cooling treatment of the original high-temperature gas discharged by the hydrogen engine 10. Figure 3

[0061] Preferably, the exhaust heating device 12 can be sleeved on the exhaust pipe between the hydrogen engine 10 and the aftertreatment system 20. Alternatively, the exhaust heating device 12 is arranged inside the exhaust pipe between the hydrogen engine 10 and the aftertreatment system 20. No matter which installation mode is adopted by the exhaust heating device 12, the original low-temperature gas discharged by the hydrogen engine 10 can be subjected to temperature rising treatment through the heat generated by the current flowing through the resistance wire.

[0062] The first temperature collecting device 13 is arranged on the exhaust pipe connected to the output end of the hydrogen engine 10, and is used for collecting the original exhaust temperature of the hydrogen engine 10.

[0063] Preferably, the first temperature collecting device 13 can be a temperature sensor.

[0064] ​​The controller 14 is connected to the exhaust cooling device 11, the exhaust heating device 12 and the first temperature acquisition device 13 respectively.

[0065] Controller 14 is used to acquire the original exhaust temperature of the hydrogen engine 10 collected by the first temperature acquisition device 13. If the original exhaust temperature exceeds... The efficient temperature range of the catalyst is determined by the relationship between the original exhaust temperature and the upper and lower temperature thresholds of the efficient temperature range. An exhaust temperature regulation strategy is determined by the current exhaust mass flow rate of the hydrogen engine 10. The target heat required to regulate the original exhaust temperature to the efficient temperature range is determined by the target heat. The exhaust cooling device 11 or exhaust heating device 12 activated in the exhaust temperature regulation strategy is controlled based on the target heat.

[0066] In this embodiment The value of the high-efficiency temperature range of the catalyst is determined according to actual needs. For example, the high-efficiency temperature range is [175℃, 225℃], that is, the upper limit temperature threshold of the high-efficiency temperature range is 225℃ and the lower limit temperature threshold is 175℃.

[0067] In practical applications, the current engine speed and torque of the hydrogen engine 10 can be directly obtained, and then the current exhaust mass flow rate corresponding to the current engine speed and torque can be determined from the correspondence between engine speed and torque and exhaust mass flow rate determined by experiments.

[0068] If the initial exhaust temperature of the hydrogen engine 10 is less than the lower limit temperature threshold, the corresponding exhaust temperature adjustment strategy is to disable the exhaust cooling device 11 and enable the exhaust heating device 12.

[0069] If the initial exhaust temperature of the hydrogen engine 10 is greater than the upper limit temperature threshold, the corresponding exhaust temperature adjustment strategy is to activate the exhaust cooling device 11 and deactivate the exhaust heating device 12.

[0070] In summary, this invention discloses an exhaust thermal management system, comprising: an exhaust cooling device 11, an exhaust heating device 12, a first temperature acquisition device 13, and a controller 14. The exhaust cooling device 11 and the exhaust heating device 12 are both installed in the hydrogen engine 10 and... On the exhaust pipe between the aftertreatment systems 20, a first temperature acquisition device 13 is installed on the exhaust pipe connected to the output end of the hydrogen engine 10 to acquire the original exhaust temperature of the hydrogen engine 10. The controller 14 determines that the original exhaust temperature exceeds the limit. When the original exhaust temperature is lower than the lower threshold of the high-efficiency temperature range of the catalyst, the original low-temperature exhaust gas discharged by the hydrogen engine 10 is heated; when the original exhaust temperature is higher than the upper threshold of the high-efficiency temperature range of the catalyst, the original high-temperature exhaust gas discharged by the hydrogen engine 10 is cooled, so that the exhaust temperature entering the exhaust aftertreatment system 20 can be ensured to be always maintained within the high-efficiency temperature range of the catalyst. The exhaust temperature of the exhaust aftertreatment system 20 is always maintained within the high-efficiency temperature range of the catalyst. The exhaust temperature of the exhaust aftertreatment system 20 is always maintained within the high-efficiency temperature range of the catalyst. The catalyst always maintains a high activity when performing the oxidation-reduction reaction on the nitrogen oxides generated by the combustion of the hydrogen engine 10.

[0071] In one embodiment, referring to Figure 4 , the embodiment of the present application discloses another schematic diagram of an exhaust heat management system, based on the embodiment shown in Figure 2 , the exhaust heat management system can further include a second temperature acquisition device 15.

[0072] The second temperature acquisition device 15 is arranged on the exhaust pipe connected to the input end of the exhaust aftertreatment system 20 and is connected to the controller 14. The second temperature acquisition device 15 is arranged on the exhaust pipe connected to the input end of the exhaust aftertreatment system 20 and is connected to the controller 14.

[0073] The second temperature acquisition device 15 is arranged on the exhaust pipe connected to the input end of the exhaust aftertreatment system 20 and is connected to the controller 14.

[0074] The controller 14 is used for acquiring the adjusted exhaust temperature, and when it is determined that the adjusted exhaust temperature is within the high-efficiency temperature range of the catalyst, the control on the activated exhaust cooling device 11 or exhaust heating device 12 is stopped.

[0075] Preferably, the second temperature acquisition device 15 can be a temperature sensor.

[0076] As can be seen from the above, the present application can ensure that the exhaust temperature entering the exhaust aftertreatment system 20 is always maintained within the high-efficiency temperature range of the catalyst. The exhaust temperature of the exhaust aftertreatment system 20 is always maintained within the high-efficiency temperature range of the catalyst. The exhaust temperature of the exhaust aftertreatment system 20 is always maintained within the high-efficiency temperature range of the catalyst. The exhaust temperature of the exhaust aftertreatment system 20 is always maintained within the high-efficiency temperature range of the catalyst. The exhaust temperature of the exhaust aftertreatment system 20 is always maintained within the high-efficiency temperature range of the catalyst. ​when the catalyst is within the high-efficiency temperature range, and when the adjusted exhaust temperature is determined to be within when the catalyst is within the high-efficiency temperature range, the adjusted exhaust temperature can be determined to be within The catalyst maintains high activity, at which time the controller 14 stops controlling the activated exhaust cooling device 11 or exhaust heating device 12.

[0077] Corresponding to the above embodiment, the application further discloses a control method of an exhaust heat management system.

[0078] Referring to Figure 5 , the application discloses a control method of an exhaust heat management system, which is applied to a controller 14 in the exhaust heat management system, and the control method comprises the following steps:

[0079] In step S101, the original exhaust temperature of the hydrogen engine 10 is acquired.

[0080] In this embodiment, the original exhaust temperature of the hydrogen engine 10 is acquired by the first temperature acquisition device 13 arranged on the exhaust pipe connected to the output end of the hydrogen engine 10.

[0081] In step S102, if the original exhaust temperature is out of the high-efficiency temperature range of the catalyst, the exhaust temperature adjustment strategy is determined according to the size relationship between the original exhaust temperature and the upper and lower temperature threshold values of the high-efficiency temperature range. when the catalyst is within the high-efficiency temperature range, the adjusted exhaust temperature can be determined to be within

[0082] In this embodiment, The value of the high-efficiency temperature range of the catalyst is determined according to actual needs, for example, the value of the high-efficiency temperature range is [175℃, 225℃], that is, the upper temperature threshold value of the high-efficiency temperature range is 225℃, and the lower temperature threshold value is 175℃.

[0083] The original exhaust temperature of the hydrogen engine 10 is compared with the upper and lower temperature threshold values to determine whether the original exhaust temperature is within the high-efficiency temperature range of the catalyst. when the catalyst is within the high-efficiency temperature range, the adjusted exhaust temperature can be determined to be within

[0084] If the original exhaust temperature is less than the lower temperature threshold value, it indicates that the exhaust temperature of the hydrogen engine 10 is low, and the exhaust temperature needs to be increased by heating, and the corresponding exhaust temperature adjustment strategy is: deactivating the exhaust cooling device 11 and activating the exhaust heating device 12.

[0085] If the original exhaust temperature is greater than the upper temperature threshold value, it indicates that the exhaust temperature of the hydrogen engine 10 is too high, and the exhaust temperature needs to be reduced by cooling, and the corresponding exhaust temperature adjustment strategy is: activating the exhaust cooling device 11 and deactivating the exhaust heating device 12.

[0086] Step S103: Determine the target heat required to adjust the original exhaust temperature to the high-efficiency temperature range based on the current exhaust mass flow rate of the hydrogen engine 10.

[0087] In practical applications, the current engine speed and torque of the hydrogen engine 10 can be directly obtained, and then the current exhaust mass flow rate corresponding to the current engine speed and torque can be determined from the correspondence between engine speed and torque and exhaust mass flow rate determined by experiments.

[0088] Step S104: Control the exhaust cooling device 11 or exhaust heating device 12 activated in the exhaust temperature regulation strategy based on the target heat.

[0089] If the initial exhaust temperature of the hydrogen engine 10 is lower than the lower limit temperature threshold of the high-efficiency temperature range, it indicates that the exhaust temperature of the hydrogen engine 10 is low and exhaust heating is required. The target heat is the amount of heat required to raise the initial exhaust temperature to the high-efficiency temperature range. The exhaust heating device 12 is controlled based on this heat.

[0090] If the initial exhaust temperature of the hydrogen engine 10 is greater than the upper temperature threshold of the high-efficiency temperature range, it indicates that the exhaust temperature of the hydrogen engine 10 is too high and exhaust cooling is required. The target heat is the amount of heat required to reduce the initial exhaust temperature to the high-efficiency temperature range. The exhaust cooling device 11 is controlled based on this amount of heat required for cooling.

[0091] In summary, this invention discloses a control method for an exhaust thermal management system, which obtains the initial exhaust temperature of the hydrogen engine 10. If the initial exhaust temperature exceeds... The efficient temperature range of the catalyst is determined by analyzing the relationship between the original exhaust temperature and the upper and lower temperature thresholds of the efficient temperature range. An exhaust temperature regulation strategy is then established. Based on the current exhaust mass flow rate of the hydrogen engine 10, a target heat required to regulate the original exhaust temperature to the efficient temperature range is determined. The exhaust cooling device 11 or exhaust heating device 12 activated in the exhaust temperature regulation strategy is then controlled based on the target heat. This invention heats the original low-temperature gas discharged from the hydrogen engine 10 when the original exhaust temperature is below the lower temperature threshold of the efficient temperature range; and cools the original high-temperature gas discharged from the hydrogen engine 10 when the original exhaust temperature is above the upper temperature threshold of the efficient temperature range. Therefore, it ensures that the gas entering the efficient temperature range... The exhaust temperature of the aftertreatment system 20 is always maintained at Within the catalyst's highly efficient temperature range, thus enabling... The catalyst maintains high activity throughout the oxidation-reduction reaction of nitrogen oxides produced by the combustion of hydrogen in the hydrogen engine 10.

[0092] In one embodiment, step S103 may specifically include:

[0093] (1) If the original exhaust temperature is less than The lower limit temperature threshold of the catalyst's high-efficiency temperature range is used to calculate the first temperature difference between the lower limit temperature threshold and the original exhaust temperature.

[0094] (2) Add the first temperature difference to the temperature drop corresponding to the heat loss to obtain the first target temperature difference.

[0095] Among them, heat loss is due to the hydrogen engine 10 and The heat loss caused by the exhaust pipe between the aftertreatment systems 20 is calibrated in the form of temperature drop in this embodiment.

[0096] (3) Multiply the first target temperature difference, the current exhaust mass flow rate of the hydrogen engine 10, the exhaust specific heat capacity and the heating time to obtain the heating heat required to heat up the original low temperature gas discharged by the hydrogen engine 10, and determine the heating heat as the target heat.

[0097] When the original exhaust temperature is less than The target heat is the heat required to raise the original exhaust temperature to the high-efficiency temperature range when the catalyst reaches the lower temperature threshold of its high-efficiency temperature range.

[0098] The expression for the amount of heat generated is as follows:

[0099] ;

[0100] In the formula, Q 加热热量 The heat capacity is represented by m1, the current exhaust mass flow rate of the hydrogen engine 10 (unit: kg / s), and the exhaust specific heat capacity (known quantity). T represents the amount of heat generated during heating. 下限温度阈值 express The lower limit temperature threshold of the catalyst's efficient temperature range, where T1 represents the initial exhaust temperature of the hydrogen engine 10.

[0101] △T represents the temperature drop corresponding to heat loss, and t1 represents the heating time.

[0102] Correspondingly, step S104 may specifically include:

[0103] (1) If the original exhaust temperature is less than The lower limit temperature threshold of the catalyst's high-efficiency temperature range is determined based on the target heat and heating time, and the heating power of the exhaust heating device 12 is determined accordingly.

[0104] It should be noted that in the embodiment, after the target heat required for heating the original exhaust gas temperature to the high-efficiency temperature range is determined, the heat release process of the exhaust gas heating device 12 is controlled according to the target heat to ensure that the heat released by the exhaust gas heating device 12 is consistent with the target heat.

[0105] The expression of the heat released by the exhaust gas heating device 12 is as follows:

[0106] Q 释放热量 =I 2 Rt1;

[0107] In the expression, Q 释放热量 represents the heat released by the exhaust gas heating device 12, R represents the resistance value of the resistance wire in the exhaust gas heating device 12 (a known quantity), I represents the current flowing through the resistance wire, t1 represents the heating time, and I 2 R represents the heating power.

[0108] It should be particularly noted that in the expression of the heating heat and the expression of the heat released by the exhaust gas heating device 12, the heating time involved is the same time variable. When the two formulas are equal, the heating time variable can be eliminated, and it will not affect the final calculation of the current flowing through the resistance wire.

[0109] (2) Calculate the current flowing through the resistance wire according to the heating power and the resistance value of the resistance wire in the exhaust gas heating device 12.

[0110] (3) Control the current flowing through the resistance wire according to the current, so that the resistance wire generates heat to warm up the original low-temperature gas discharged by the hydrogen engine 10.

[0111] In one embodiment, step S103 can specifically include:

[0112] (1) If the original exhaust gas temperature is greater than the upper limit temperature threshold of the high-efficiency temperature range of the catalyst, calculate a second temperature difference value between the original exhaust gas temperature and the upper limit temperature threshold.

[0113] (2) Subtract the second temperature difference value from the temperature drop corresponding to the heat loss to obtain a second target temperature difference value.

[0114] The heat loss is the heat loss caused by the exhaust pipe between the hydrogen engine 10 and the aftertreatment system 20, which is calibrated in the form of temperature drop in the embodiment.

[0115] (3) multiplying the second target temperature difference value, the current exhaust mass flow rate of the hydrogen engine 10, the specific heat capacity of the exhaust gas, and the temperature reduction time to obtain a temperature reduction heat required when reducing the original high-temperature gas discharged by the hydrogen engine 10, and determining the temperature reduction heat as the target heat.

[0116] When the original exhaust gas temperature is greater than the upper limit temperature threshold of the high-efficiency temperature range of the catalyst The target heat is the temperature reduction heat required to reduce the original exhaust gas temperature to the high-efficiency temperature range.

[0117] The expression of the temperature reduction heat is as follows:

[0118] ;

[0119] In the formula, Q represents the temperature reduction heat, m1 represents the current exhaust mass flow rate (unit: kg / s) of the hydrogen engine 10, c1 represents the specific heat capacity of the exhaust gas (a known quantity), T 降温热量 represents the temperature reduction heat, m1 represents the current exhaust mass flow rate (unit: kg / s) of the hydrogen engine 10, c1 represents the specific heat capacity of the exhaust gas (a known quantity), T 上限温度阈值 represents the temperature reduction heat, m1 represents the current exhaust mass flow rate (unit: kg / s) of the hydrogen engine 10, c1 represents the specific heat capacity of the exhaust gas (a known quantity), T The upper limit temperature threshold of the high-efficiency temperature range of the catalyst, T1 represents the original exhaust gas temperature of the hydrogen engine 10,

[0120] △T represents the temperature drop corresponding to the heat loss, and t2 represents the temperature reduction time.

[0121] Correspondingly, step S104 can specifically include:

[0122] (1) If the original exhaust gas temperature is greater than the upper limit temperature threshold, a third temperature difference value is obtained by calculating the difference between the temperature of the cooling liquid flowing out of the exhaust gas temperature reduction device 11 and the temperature of the cooling liquid flowing into the exhaust gas temperature reduction device 11.

[0123] (2) Based on the target heat, the third temperature difference value, the specific heat capacity of the cooling liquid, and the temperature reduction time, a cooling liquid mass flow rate is obtained.

[0124] It should be noted that in the present embodiment, after determining the target heat required to reduce the original exhaust gas temperature to the high-efficiency temperature range, the temperature reduction process of the exhaust gas temperature reduction device 11 needs to be precisely controlled according to the determined target heat, so as to ensure that the actual heat quantity discharged by the exhaust gas temperature reduction device 11 is consistent with the target heat.

[0125] The expression of the heat quantity discharged by the cooling liquid in the exhaust gas temperature reduction device 11 is as follows:

[0126] ;

[0127] In the formula, Q represents the heat quantity discharged by the cooling liquid, m2 represents the cooling liquid mass flow rate (unit: kg / s), c2 represents the specific heat capacity of the cooling liquid (a known quantity), and T 冷却液represents the heat transferred by the coolant in the exhaust gas cooling device 11, m2 represents the mass flow rate of the coolant, c2 represents the specific heat capacity of the coolant, T out represents the temperature of the coolant when it flows out of the exhaust gas cooling device 11, T in represents the temperature of the coolant when it flows into the exhaust gas cooling device 11, and t2 represents the cooling time.

[0128] It should be particularly noted that the cooling time involved in the expression of the cooling heat and the expression of the heat transferred by the coolant in the exhaust gas cooling device 11 is the same time variable. When the two formulas are equal, the variable of the cooling time can be eliminated, and it will not affect the final calculation of the mass flow rate of the coolant.

[0129] (3) Controlling the flow rate of the coolant according to the mass flow rate of the coolant to cool the original high-temperature gas discharged by the hydrogen engine 10.

[0130] When the exhaust heat management system further comprises a second temperature acquisition device 15, after step S104, the control method of the exhaust heat management system can further comprise:

[0131] acquiring the adjusted exhaust temperature of the hydrogen engine 10 collected by the second temperature acquisition device 15;

[0132] If the adjusted exhaust temperature is located within the high-efficiency temperature range of the catalyst, stopping the control of the enabled exhaust gas cooling device 11 or exhaust gas heating device 12.

[0133] The second temperature acquisition device 15 is arranged on the exhaust pipe connected to the input end of the aftertreatment system 20. To ensure that the original exhaust gas output by the hydrogen engine 10 can be adjusted to

[0134] the high-efficiency temperature range of the catalyst after being adjusted by the exhaust gas cooling device 11 or the exhaust gas heating device 12 before entering the aftertreatment system 20, the present application arranges the second temperature acquisition device 15 on the exhaust pipe connected to the input end of the aftertreatment system 20 to detect the adjusted exhaust temperature. When it is determined that the adjusted exhaust temperature is located within the high-efficiency temperature range of the catalyst, the control operation of the enabled exhaust gas cooling device 11 or exhaust gas heating device 12 is stopped.

[0135] Referring to Figure 6 , a specific embodiment of the present application discloses a control method flow chart of an exhaust heat management system, and the whole control process is as follows:

[0136] It is assumed that ​​The lower temperature threshold of the high-efficiency temperature range of the catalyst is A, and the upper temperature threshold is B.

[0137] 1) Obtain the original exhaust temperature T1 of the hydrogen engine.

[0138] 2) Compare the original exhaust temperature T1 with the lower temperature threshold A and the upper temperature threshold B respectively, and determine whether T1 B or A ≤ T1 ≤ B.

[0139] 3) If A ≤ T1 ≤ B, control the exhaust cooling device and the exhaust heating device to be disabled, and determine whether the engine continues to run, if not, end the entire control process, if yes, return to 1).

[0140] 4) If T1 < A, determine the exhaust temperature adjustment strategy as: the exhaust cooling device is disabled and the exhaust heating device is enabled;

[0141] 5) Calculate the heating heat required for heating the original low-temperature gas discharged by the hydrogen engine, and determine the current flowing through the resistance wire in the exhaust heating device according to the heating heat.

[0142] 6) Control the current flowing through the resistance wire according to the calculated current.

[0143] 7) Determine whether the adjusted exhaust temperature T2 obtained after heating is in [A, B], if not, return to 5), if yes, control the exhaust cooling device and the exhaust heating device to be disabled.

[0144] 8) If T1 > B, determine the exhaust temperature adjustment strategy as: the exhaust cooling device is enabled and the exhaust heating device is disabled;

[0145] 9) Calculate the cooling heat required for cooling the original high-temperature gas discharged by the hydrogen engine, and determine the mass flow rate of the cooling liquid according to the cooling heat.

[0146] 10) Control the flow rate of the cooling liquid according to the mass flow rate of the cooling liquid;

[0147] 11) Determine whether the adjusted exhaust temperature T2 obtained after cooling is in [A, B], if not, return to 9), if yes, control the exhaust cooling device and the exhaust heating device to be disabled.

[0148] Corresponding to the above embodiment, the application also discloses an engine exhaust system, which is described in detail in Figure 2 , the engine exhaust system comprises an exhaust heat management system and an aftertreatment system 20, the exhaust heat management system is connected with the aftertreatment system 20, and the connection relationship is described in detail in Figure 2 the corresponding part of the embodiment, which will not be repeated here.

[0149] Corresponding to the above-mentioned embodiments, the application also discloses a vehicle, which comprises a hydrogen engine 10, an exhaust heat management system arranged between the hydrogen engine 10 and the exhaust aftertreatment system 20. The exhaust heat management system is connected with the hydrogen engine 10 and the exhaust aftertreatment system 20. The connection relationship of the exhaust heat management system with the hydrogen engine 10 and the exhaust aftertreatment system 20 will be described in detail below. The exhaust heat management system comprises a heat exchanger 30, Figure 2 and Figure 2 Corresponding parts of the embodiments will not be described here again.

[0150] Finally, it should be noted that, in this document, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0151] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between various embodiments can be referred to each other.

[0152] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An exhaust heat management system, characterized in that, include: Exhaust cooling device (11), exhaust heating device (12), first temperature acquisition device (13) and controller (14); The exhaust cooling device (11) and the exhaust heating device (12) are both installed in the hydrogen engine (10) and On the exhaust pipe between the aftertreatment systems (20); The first temperature acquisition device (13) is installed on the exhaust pipe connected to the output end of the hydrogen engine (10) and is located between the hydrogen engine (10) and the exhaust cooling device (11) to acquire the original exhaust temperature of the hydrogen engine (10). The controller (14) is connected to the exhaust cooling device (11), the exhaust heating device (12), and the first temperature acquisition device (13) respectively, and is used to acquire the original exhaust temperature. If the original exhaust temperature exceeds the specified value, the controller will detect the exhaust temperature. The efficient temperature range of the catalyst is determined by the relationship between the original exhaust temperature and the upper and lower temperature thresholds of the efficient temperature range. An exhaust temperature regulation strategy is determined by the current exhaust mass flow rate of the hydrogen engine (10) to determine the target heat required to regulate the original exhaust temperature to the efficient temperature range. The exhaust cooling device (11) or exhaust heating device (12) activated in the exhaust temperature regulation strategy is controlled based on the target heat. The determination of the target heat required to adjust the original exhaust temperature to the high-efficiency temperature range based on the current exhaust mass flow rate of the hydrogen engine (10) includes: If the original exhaust temperature is less than the lower limit temperature threshold, calculate the first temperature difference between the lower limit temperature threshold and the original exhaust temperature. The first temperature difference is added to the temperature drop corresponding to the heat loss to obtain the first target temperature difference, wherein the heat loss is the temperature drop caused by the hydrogen engine (10) and the heat loss caused by the heat loss. Heat loss caused by exhaust pipes between aftertreatment systems (20); Multiply the first target temperature difference, the current exhaust mass flow rate, the exhaust specific heat capacity, and the heating time to obtain the heating heat required to heat up the original low-temperature gas discharged from the hydrogen engine (10), and determine the heating heat as the target heat. as well as, If the original exhaust temperature is greater than the upper limit temperature threshold, calculate the second temperature difference between the original exhaust temperature and the upper limit temperature threshold; Subtract the second temperature difference from the temperature drop corresponding to the heat loss to obtain the second target temperature difference; Multiply the second target temperature difference, the current exhaust mass flow rate, the exhaust specific heat capacity, and the cooling time to obtain the cooling heat required to cool the original high-temperature gas discharged from the hydrogen engine (10), and determine the cooling heat as the target heat.

2. The exhaust heat management system according to claim 1, characterized in that, The exhaust cooling device (11) includes: a water jacket exhaust pipe; The water jacket exhaust pipe is fitted onto the hydrogen engine (10) and the... On the exhaust pipe between the aftertreatment system (20), the original high-temperature gas discharged from the hydrogen engine (10) is cooled by the flow of coolant.

3. The exhaust heat management system according to claim 1 or 2, characterized in that, The exhaust heating device (12) is fitted onto the hydrogen engine (10) and the... On the exhaust pipe between the aftertreatment system (20), or, located on the hydrogen engine (10) and the exhaust pipe between the aftertreatment system (20). Inside the exhaust pipe between the aftertreatment system (20), the heat generated when the current flows through the resistance wire is used to heat up the original low-temperature gas discharged from the hydrogen engine (10).

4. The exhaust heat management system according to claim 1 or 2, characterized in that, Also includes: Second temperature acquisition device (15); The second temperature acquisition device (15) is installed in the The input end of the aftertreatment system (20) is connected to the exhaust pipe and connected to the controller (14); The second temperature acquisition device (15) is used to acquire the adjusted exhaust temperature of the hydrogen engine (10); The controller (14) is used to obtain the adjusted exhaust temperature. When it is determined that the adjusted exhaust temperature is within the high-efficiency temperature range, the controller stops controlling the activated exhaust cooling device (11) or the exhaust heating device (12).

5. A control method for an exhaust heat management system, characterized in that, The control method, applied to the exhaust heat management system according to any one of claims 1 to 4, comprises: Obtain the raw exhaust temperature of the hydrogen engine (10); If the original exhaust temperature exceeds The efficient temperature range of the catalyst is determined by the exhaust temperature regulation strategy based on the relationship between the original exhaust temperature and the upper and lower temperature thresholds of the efficient temperature range. The target heat required to adjust the original exhaust temperature to the high-efficiency temperature range is determined based on the current exhaust mass flow rate of the hydrogen engine (10). The exhaust cooling device (11) or exhaust heating device (12) activated in the exhaust temperature regulation strategy is controlled based on the target heat.

6. The control method according to claim 5, characterized in that, The process of determining the exhaust temperature regulation strategy includes: If the original exhaust temperature is less than the lower limit temperature threshold, the exhaust temperature adjustment strategy is to disable the exhaust cooling device (11) and enable the exhaust heating device (12). or, If the original exhaust temperature is greater than the upper limit temperature threshold, the exhaust temperature adjustment strategy is to activate the exhaust cooling device (11) and deactivate the exhaust heating device (12).

7. The control method according to claim 5, characterized in that, The control of the exhaust cooling device (11) or exhaust heating device (12) activated in the exhaust temperature regulation strategy based on the target heat includes: If the original exhaust temperature is less than the lower limit temperature threshold, the heating power of the exhaust heating device (12) is determined according to the target heat and heating time; The current flowing through the resistance wire is calculated based on the heating power and the resistance value of the resistance wire inside the exhaust heating device (12); The current flowing through the resistance wire is controlled according to the current, so that the resistance wire generates heat and heats up the original low-temperature gas discharged from the hydrogen engine (10).

8. The control method according to claim 5, characterized in that, The control of the exhaust cooling device (11) or exhaust heating device (12) activated in the exhaust temperature regulation strategy based on the target heat includes: If the original exhaust temperature is greater than the upper limit temperature threshold, the difference between the temperature of the coolant flowing out of the exhaust cooling device (11) and the temperature of the coolant entering is calculated to obtain a third temperature difference. Based on the target heat, the third temperature difference, the specific heat capacity of the coolant, and the cooling time, the coolant mass flow rate is obtained; The flow rate of the coolant is controlled according to the mass flow rate of the coolant in order to cool down the original high-temperature gas discharged from the hydrogen engine (10).

9. The control method according to claim 5, characterized in that, When the exhaust thermal management system further includes a second temperature acquisition device (15), after the step of controlling the exhaust cooling device (11) or exhaust heating device (12) activated in the exhaust temperature regulation strategy based on the target heat, the system further includes: The second temperature acquisition device (15) is used to acquire the adjusted exhaust temperature of the hydrogen engine (10). On the exhaust pipe connected to the input end of the aftertreatment system (20); If the adjusted exhaust temperature is within the high-efficiency temperature range, stop controlling the activated exhaust cooling device (11) or exhaust heating device (12).

10. An engine exhaust system, characterized in that, Including the exhaust heat management system as described in any one of claims 1 to 4, and Post-processing system (20).

11. A vehicle, characterized in that, include: Hydrogen engine (10) The aftertreatment system (20) and the exhaust thermal management system according to any one of claims 1 to 4, wherein the exhaust thermal management system is disposed in the hydrogen engine (10) and the... Between the post-processing systems (20).

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