Ammonia injection control system, method and vehicle

Abstract

The present application is applicable to the field of vehicle technology, and provides an ammonia injection control system, method and vehicle, wherein the ammonia injection control system includes a urea tank, a urea pump, a urea injector, a reactor, a pressure regulating tank, an ammonia injector and a control unit; the urea tank is connected to the urea injector through the urea pump, and the injection port of the urea injector is arranged in the reactor; the reactor, the pressure regulating tank and the ammonia injector are connected in sequence, and the injection port of the ammonia injector is arranged on the post-processing system; the control unit is electrically connected to the urea pump, the urea injector and the ammonia injector respectively. When the vehicle is in the starting state, the control unit controls the urea pump to rotate forward, and controls the urea injector and the ammonia injector to open; when the vehicle is turned off, the control unit controls the urea pump to reverse, so that the urea injector and the urea solution in the pipeline flow back to the urea tank, which can solve the problem that the urea solution is easy to crystallize in the post-processing system, resulting in the problem that the vehicle exhaust gas cannot meet the emission standards.

Description

Technical Field

[0001] The present application belongs to the field of vehicle technology, and in particular, relates to an ammonia injection control system, method and vehicle. Background Art

[0002] In order to reduce the nitrogen oxide gas in the exhaust of diesel vehicles, the vehicle is equipped with an SCR (Selective Catalytic Reduction) system, which uses urea solution to reduce the nitrogen oxide gas, and finally generates nitrogen and water to achieve the effect of reducing the nitrogen oxide gas in the vehicle exhaust.

[0003] When the engine exhaust temperature is lower than 180°C, urea solution is prone to white crystals, which can cause blockages in urea nozzles, exhaust pipes, and post-processors after a large amount of accumulation. At the same time, in cold regions, the residual urea solution after the vehicle is turned off freezes and expands under low temperature conditions, causing the urea solution nozzle to stick and clog, and the urea solution to be sprayed too little or unable to be sprayed normally, resulting in a reduced conversion efficiency of nitrogen oxides in vehicle exhaust gas and failure to meet emission standards. Summary of the invention

[0004] The embodiments of the present application provide an ammonia injection control system, method and vehicle, which can solve the problem that urea solution is easy to crystallize in the post-treatment system, resulting in the vehicle exhaust gas failing to meet the emission standards.

[0005] In a first aspect, an embodiment of the present application provides an ammonia injection control system, comprising a urea tank, a urea pump, a urea injector, a reactor, a pressure stabilizing tank, an ammonia injector and a control unit; the urea tank is connected to the urea injector through the urea pump, and the injection port of the urea injector is arranged in the reactor; the reactor, the pressure stabilizing tank and the ammonia injector are connected in sequence, and the injection port of the ammonia injector is arranged on a post-treatment system; the control unit is electrically connected to the urea pump, the urea injector and the ammonia injector respectively;

[0006] When the vehicle is in the starting state, the control unit controls the urea pump to rotate forward, and controls the urea injector and the ammonia injector to open, the urea solution in the urea tank is injected into the reactor by the urea injector through the urea pump, and reacts with the catalyst in the reactor to generate ammonia; the ammonia generated in the reactor enters the pressure stabilizing tank; the ammonia in the pressure stabilizing tank is injected into the post-treatment system by the ammonia injector;

[0007] When the vehicle is turned off, the control unit controls the urea pump to reverse, so that the urea solution in the urea injector and the pipeline flows back to the urea tank.

[0008] In a possible implementation of the first aspect, the ammonia injection control system further includes an air compressor, the air compressor is communicated with the reactor, and the air compressor is electrically connected to the control unit;

[0009] When the vehicle is turned off, the control unit controls the air compressor to operate and inject air into the reactor, so that the reactor, the pressure stabilizing tank, the ammonia injector and the ammonia in the pipeline enter the post-treatment system.

[0010] In a possible implementation manner of the first aspect, the ammonia injection control system further includes an air filter, and the air filter is connected to an air inlet of the air compressor.

[0011] In a possible implementation manner of the first aspect, the ammonia injection control system further includes a pressure relief valve, which is connected in series between the urea tank and the pressure stabilizing tank.

[0012] In a possible implementation manner of the first aspect, the ammonia injection control system further includes a pressure reducing valve, which is connected in series between the reactor and the pressure stabilizing tank, and is electrically connected to the control unit.

[0013] In a possible implementation of the first aspect, the ammonia injection control system also includes a shut-off valve, which is connected in series between the pressure reducing valve and the pressure stabilizing tank, and is electrically connected to the control unit, and is used to open or close according to a control signal of the control unit.

[0014] In a possible implementation of the first aspect, the ammonia injection control system further includes a pressure acquisition unit, a temperature acquisition unit, and a nitrogen oxide detection unit, and the pressure acquisition unit, the temperature acquisition unit, and the nitrogen oxide detection unit are all electrically connected to the control unit;

[0015] When the vehicle is in a starting state, the pressure acquisition unit is used to acquire the real-time air pressure in the pressure stabilizing tank, the temperature acquisition unit is used to acquire the exhaust temperature of the engine, the nitrogen oxide detection unit is used to acquire the concentration of nitrogen oxides in the engine exhaust, and the control unit is used to control the forward rotation speed of the urea pump and control the opening of the urea injector according to the real-time air pressure and a preset air pressure range; the control unit is also used to control the injection amount of the ammonia injector according to the exhaust temperature, the concentration of nitrogen oxides and a preset nitrogen oxide conversion rate.

[0016] In a second aspect, an embodiment of the present application provides an ammonia injection control method, which is applied to the ammonia injection control system described in any one of the first aspects, and the ammonia injection control method includes:

[0017] When the vehicle is in the starting state, the real-time air pressure in the pressure regulating box, the exhaust temperature of the engine and the concentration of nitrogen oxides in the engine exhaust are obtained;

[0018] According to the real-time air pressure and the preset air pressure range, the forward rotation speed of the urea pump is controlled, and the opening of the urea injector is controlled;

[0019] The injection amount of the ammonia injector is controlled according to the exhaust temperature, the concentration of the nitrogen oxides and a preset nitrogen oxygen conversion rate.

[0020] In a possible implementation manner of the second aspect, the ammonia injection control method further includes:

[0021] When the vehicle is turned off, the urea pump is controlled to reverse, so that the urea solution in the urea injector and the pipeline flows back to the urea tank.

[0022] In a third aspect, an embodiment of the present application provides a vehicle, comprising the ammonia injection control system described in any one of the first aspects.

[0023] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0024] The embodiment of the present application provides an ammonia injection control system. When the vehicle is in the starting state, the control unit controls the urea pump to rotate forward, and controls the urea injector and the ammonia injector to open. The urea solution in the urea tank is injected into the reactor by the urea injector through the urea pump, and reacts with the catalyst in the reactor to generate ammonia. The ammonia generated in the reactor enters the pressure regulating tank, and the ammonia in the pressure regulating tank is injected into the post-treatment system by the ammonia injector to reduce the nitrogen oxide gas. The ammonia injection control system provided in the embodiment of the present application injects ammonia into the post-treatment system to replace the original urea solution, which can effectively solve the problem that the vehicle exhaust gas does not meet the emission standards due to the crystallization of the urea solution.

[0025] When the vehicle is turned off, the control unit controls the urea pump to reverse, so that the urea solution in the urea injector and the pipeline flows back to the urea tank to prevent the urea solution from crystallizing and causing blockage of the urea injector and the pipeline, and ensure that when the vehicle is started again, the ammonia injection control system can still normally inject ammonia to the post-treatment system to ensure that the vehicle's exhaust emissions meet the emission standards.

[0026] It can be understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0028] Figure 1 is a schematic diagram of the structure of an ammonia injection control system provided in one embodiment of the present application;

[0029] Figure 2 is a structural schematic diagram of an ammonia injection control system provided by another embodiment of the present application;

[0030] Figure 3 It is a flow chart of an ammonia injection control method provided in one embodiment of the present application.

[0031] In the figure: 101, urea tank; 102, urea pump; 103, urea injector; 104, reactor; 105, pressure stabilizing tank; 106, ammonia injector; 107, control unit; 108, post-treatment system; 109, air compressor; 110, air filter; 111, pressure relief valve; 112, pressure reducing valve; 113, shut-off valve. DETAILED DESCRIPTION

[0032] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0033] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0034] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0035] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0036] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0037] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0038] Figure 1 FIG. 1 shows a schematic diagram of the structure of an ammonia injection control system provided by an embodiment of the present application. Figure 1 As shown, the ammonia injection control system includes a urea tank 101, a urea pump 102, a urea injector 103, a reactor 104, a pressure stabilizing tank 105, an ammonia injector 106 and a control unit 107. The urea tank 101 is connected to the urea injector 103 through the urea pump 102, and the injection port of the urea injector 103 is arranged in the reactor 104. The reactor 104, the pressure stabilizing tank 105 and the ammonia injector 106 are connected in sequence, and the injection port of the ammonia injector 106 is arranged on the post-treatment system 108. The control unit 107 is electrically connected to the urea pump 102, the urea injector 103 and the ammonia injector 106 respectively.

[0039] Specifically, when the vehicle is in the starting state, the control unit 107 controls the urea pump 102 to rotate forward, and controls the urea injector 103 and the ammonia injector 106 to open. Under the action of the urea pump 102, the urea solution in the urea tank 101 is transported to the urea injector 103, and the urea injector 103 injects the urea solution into the reactor 104. The reactor 104 contains a urea hydrolysis catalyst, and the reactor 104 maintains the pressure and temperature required for urea hydrolysis. The urea solution in the reactor 104 reacts chemically with the urea hydrolysis catalyst to produce ammonia. The generation of ammonia in the reactor 104 increases the air pressure in the reactor 104, and the ammonia in the reactor 104 enters the pressure stabilizing tank 105. The ammonia entering the pressure stabilizing tank 105 also increases the air pressure in the pressure stabilizing tank 105, and the ammonia in the pressure stabilizing tank 105 is injected into the post-treatment system 108 by the ammonia injector 106. The post-treatment system 108 has a post-treatment catalyst. Under the action of the post-treatment catalyst, ammonia reduces nitrogen oxides in the exhaust gas into nitrogen and water through an oxidation-reduction reaction, thereby reducing the emission of nitrogen oxides gas from the vehicle and meeting the vehicle exhaust emission standards. The ammonia injection control system provided in the embodiment of the present application injects ammonia into the post-treatment system 108 to replace the original urea solution, which can effectively solve the problem that the vehicle exhaust emission does not meet the emission standards due to the crystallization of the urea solution.

[0040] When the vehicle is turned off, the control unit 107 controls the urea pump 102 to reverse, so that the urea solution in the urea injector 103 and the pipeline flows back to the urea tank 101, to prevent the urea solution from crystallizing and causing blockage of the urea injector 103 and the pipeline, to ensure that when the vehicle is started again, the ammonia injection control system can still normally inject ammonia to the post-treatment system 108, to ensure that the vehicle exhaust meets the emission standards.

[0041] It should be noted that the designer may set the duration of the control unit 107 controlling the reversal of the urea pump 102 according to actual conditions. For example, the duration of the reversal of the urea pump 102 may be set to 0.5 minutes, 1 minute, 2 minutes or other time.

[0042] Figure 2 FIG. 2 shows a schematic diagram of the structure of an ammonia injection control system provided by another embodiment of the present application. Figure 2 As shown, the ammonia injection control system further includes an air compressor 109 , which is communicated with the reactor 104 , and is electrically connected to the control unit 107 .

[0043] Specifically, when the vehicle is turned off, the control unit 107 controls the air compressor 109 to work, injects air into the reactor 104, and causes the reactor 104, the pressure stabilizing tank 105, the ammonia injector 106, and the ammonia in the pipeline to enter the post-treatment system 108. The ammonia entering the post-treatment system 108 reacts chemically with the nitrogen oxides in the exhaust gas under the action of the post-treatment catalyst, so that the ammonia in the reactor 104, the pressure stabilizing tank 105, the ammonia injector 106, and the pipeline is consumed, preventing the ammonia from being discharged outside the vehicle to pollute the environment, thereby improving the safety of the ammonia injection control system.

[0044] like Figure 2 As shown, the ammonia injection control system further includes an air filter 110 , and the air filter 110 is connected to the air inlet of the air compressor 109 .

[0045] Specifically, the air filter 110 can filter the air to prevent debris and dust in the air from entering the reactor 104, the pressure regulating box 105 and the ammonia injector 106 to cause blockage, thereby ensuring that the ammonia injection control system can operate normally and improving the stability of the ammonia injection control system.

[0046] like Figure 2 As shown, the ammonia injection control system further includes a pressure relief valve 111 , which is connected in series between the urea tank 101 and the pressure stabilizing tank 105 .

[0047] Specifically, the pressure relief valve 111 can use a mechanical pressure relief valve 111, and the pressure relief valve 111 has an opening pressure. When there is too much ammonia in the pressure stabilizing tank 105, the air pressure in the pressure stabilizing tank 105 will be greater than the opening pressure of the pressure relief valve 111, and the pressure relief valve 111 will open. The ammonia in the pressure stabilizing tank 105 will enter the urea tank 101 through the pipeline and dissolve in the urea solution in the urea tank 101. When the air pressure in the pressure stabilizing tank 105 is less than the opening pressure of the pressure relief valve 111, the pressure relief valve 111 is in a closed state. In this way, the pressure in the pressure stabilizing tank 105 can be prevented from being too high.

[0048] The pressure relief valve 111 can also use an electronic pressure relief valve 111, and the pressure relief valve 111 is electrically connected to the control unit 107, and the control unit 107 can control the pressure relief valve 111 to be opened or closed. A pressure collection unit is provided in the pressure stabilizing tank 105, and the pressure collection unit is used to collect the real-time air pressure in the pressure stabilizing tank 105 and transmit the real-time air pressure to the control unit 107. The control unit 107 compares the real-time air pressure with the first preset air pressure. When the real-time air pressure is greater than the first preset air pressure, the control unit 107 controls the pressure relief valve 111 to open, and the ammonia in the pressure stabilizing tank 105 will enter the urea tank 101 through the pipeline and dissolve in the urea solution in the urea tank 101. When the real-time air pressure is less than the first preset air pressure, the control unit 107 controls the pressure relief valve 111 to be closed. In this way, the pressure in the pressure stabilizing tank 105 can be prevented from being too high.

[0049] It should be noted that the designer may set the specific value of the opening pressure or the first preset air pressure according to actual conditions.

[0050] like Figure 2 As shown, the ammonia injection control system further includes a pressure reducing valve 112 , which is connected in series between the reactor 104 and the pressure stabilizing tank 105 , and is electrically connected to the control unit 107 .

[0051] Specifically, when the real-time air pressure is less than the second preset air pressure, the control unit 107 controls the opening of the pressure reducing valve 112 to increase, speeding up the speed at which the ammonia in the reactor 104 enters the pressure stabilizing tank 105, increasing the amount of ammonia in the pressure stabilizing tank 105 and increasing the air pressure in the pressure stabilizing tank 105. Therefore, the additional pressure reducing valve 112 and the pressure relief valve 111 in the ammonia injection control system can maintain the air pressure in the pressure stabilizing tank 105 within a preset pressure range, thereby meeting the ammonia usage requirement of the post-treatment system 108.

[0052] It should be noted that designers can set the specific value of the second preset air pressure according to actual conditions.

[0053] like Figure 2 As shown, the ammonia injection control system also includes a shut-off valve 113, which is connected in series between the pressure reducing valve 112 and the pressure stabilizing tank 105. The shut-off valve 113 is electrically connected to the control unit 107, and the shut-off valve 113 is used to open or close according to the control signal of the control unit 107.

[0054] Specifically, the control unit 107 can control the opening or closing of the shutoff valve 113. When the control unit 107 controls the shutoff valve 113 to open, the ammonia generated in the reactor 104 can enter the pressure stabilizing tank 105 through the shutoff valve 113. When the control unit 107 controls the shutoff valve 113 to close, the ammonia generated in the reactor 104 cannot enter the pressure stabilizing tank 105. The control unit 107 controls the opening or closing of the shutoff valve 113 to control the ammonia generated in the reactor 104 to enter the pressure stabilizing tank 105.

[0055] In one embodiment of the present application, the ammonia injection control system further includes a pressure acquisition unit, a temperature acquisition unit and a nitrogen oxide detection unit, and the pressure acquisition unit, the temperature acquisition unit and the nitrogen oxide detection unit are all electrically connected to the control unit 107 .

[0056] Specifically, when the vehicle is in the starting state, the pressure acquisition unit acquires the real-time air pressure in the pressure stabilizing tank 105, the temperature acquisition unit acquires the exhaust temperature of the engine, and the nitrogen oxide detection unit acquires the concentration of nitrogen oxides in the exhaust of the engine. The control unit 107 controls the forward rotation speed of the urea pump 102 and controls the opening of the urea injector 103 according to the real-time air pressure and the preset air pressure range. Under the action of the urea pump 102, the urea solution in the urea tank 101 is transported to the urea injector 103, and the urea injector 103 injects the urea solution into the reactor 104. The reactor 104 contains a urea hydrolysis catalyst, and the pressure and temperature required for urea hydrolysis are maintained in the reactor 104. The urea solution in the reactor 104 reacts chemically with the urea hydrolysis catalyst to produce ammonia. The control unit 107 controls the rotation speed of the urea pump 102 and the speed at which the urea injector 103 sprays the urea solution into the reactor 104, so that the ammonia generated in the reactor 104 maintains a preset concentration, and sufficient ammonia enters the pressure stabilizing tank 105, so that the air pressure in the pressure stabilizing tank 105 is maintained within a preset pressure range, ensuring that the ammonia in the pressure stabilizing tank 105 can be smoothly injected into the post-treatment system 108 through the ammonia injector 106.

[0057] The maximum atmospheric pressure in the preset air pressure range is the third preset air pressure, and the minimum atmospheric pressure is the fourth preset air pressure. When the real-time air pressure is greater than the third preset air pressure, the control unit 107 controls the urea pump 102 to reduce the rotation speed, reduce the speed at which the urea injector 103 injects the urea solution into the reactor 104, reduce the generation speed of ammonia, and reduce the speed at which the ammonia in the reactor 104 enters the pressure stabilizing tank 105, thereby reducing the air pressure in the pressure stabilizing tank 105. When the real-time air pressure is less than the fourth preset air pressure, the control unit 107 controls the urea pump 102 to increase the rotation speed, increase the speed at which the urea injector 103 injects the urea solution into the reactor 104, increase the generation speed of ammonia, and increase the speed at which the ammonia in the reactor 104 enters the pressure stabilizing tank 105, thereby increasing the air pressure in the pressure stabilizing tank 105. In this way, the air pressure in the pressure stabilizing tank 105 is maintained within the preset air pressure range, ensuring that the ammonia in the pressure stabilizing tank 105 can be smoothly injected into the post-treatment system 108 through the ammonia injector 106.

[0058] The control unit 107 calculates the ammonia injection requirement according to the exhaust temperature, the concentration of nitrogen oxides and the preset nitrogen oxygen conversion rate, and then performs ammonia injection according to the calculated ammonia injection requirement.

[0059] Specifically, the opening of the ammonia injector 106 may be controlled according to the ammonia injection demand. The larger the ammonia injection demand is, the larger the opening of the ammonia injector 106 is controlled by the control unit 107; the smaller the ammonia injection demand is, the smaller the opening of the ammonia injector 106 is controlled by the control unit 107. In this way, the ammonia injector 106 injects an appropriate amount of ammonia to the post-treatment system 108, ensuring that the exhaust gas discharged by the vehicle meets the emission standards.

[0060] Specifically, the opening time of the ammonia injector 106 may be controlled according to the ammonia injection demand. The larger the determined ammonia injection demand, the longer the opening time of the ammonia injector 106 controlled by the control unit 107; the smaller the determined ammonia injection demand, the shorter the opening time of the ammonia injector 106 controlled by the control unit 107. In this way, the ammonia injector 106 injects an appropriate amount of ammonia to the post-treatment system 108, ensuring that the exhaust gas discharged by the vehicle meets the emission standards.

[0061] In one embodiment of the present application, the control unit 107 may include one controller or two controllers. When the control unit 107 includes one controller, the controller may be an ECU (Electronic Control Unit) controller on the vehicle, and the ECU controller is electrically connected to the urea pump 102, the urea injector 103, the ammonia injector 106, the pressure reducing valve 112, the shut-off valve 113, the pressure acquisition unit, the temperature acquisition unit and the nitrogen oxide detection unit, respectively. The control principle of the ECU controller on the ammonia injection control system refers to the description of the control of the ammonia injection control system by the control unit 107, which will not be repeated here.

[0062] When the control unit 107 includes two controllers, the two controllers may be an ECU controller and a DCU (Dosing Control Unit, urea injection control unit) controller, wherein the ECU controller is electrically connected to the pressure reducing valve 112, the shut-off valve 113, the pressure acquisition unit, the temperature acquisition unit and the nitrogen oxide detection unit, respectively, the DCU controller is electrically connected to the urea pump 102, the urea injector 103 and the ammonia injector 106, respectively, and the ECU controller is electrically connected to the DCU controller.

[0063] The ECU controller determines the target rotation speed of the urea pump 102 according to the real-time air pressure and the preset air pressure range, and sends a first control signal containing the target rotation speed to the DCU controller. The DCU controller controls the urea pump 102 to rotate forward at the target rotation speed according to the first control signal, and controls the urea injector 103 to open.

[0064] The ECU controller calculates the ammonia injection demand according to the exhaust temperature, the concentration of nitrogen oxides and the preset nitrogen-oxygen conversion rate, and then determines the injection amount of the ammonia injector 106 according to the ammonia injection demand, and sends a second control signal containing the target injection amount to the DCU controller. The DCU controller controls the target opening degree or target opening duration of the ammonia injector 106 according to the second control signal, so that the ammonia injector 106 injects an appropriate amount of ammonia to the post-treatment system 108 to ensure that the vehicle exhaust meets the emission standards.

[0065] Figure 3 FIG. 1 is a flow chart of an ammonia injection control method provided by an embodiment of the present application. Figure 3 As shown, the ammonia injection control method includes steps S301 to S303.

[0066] Step S301, when the vehicle is in the starting state, obtain the real-time air pressure in the pressure regulating tank 105, the exhaust temperature of the engine and the concentration of nitrogen oxides in the exhaust gas of the engine.

[0067] Specifically, when the vehicle is in the starting state, the pressure acquisition unit acquires the real-time air pressure in the pressure stabilizing tank 105, the temperature acquisition unit acquires the exhaust temperature of the engine, and the nitrogen oxide detection unit acquires the concentration of nitrogen oxides in the engine exhaust.

[0068] Step S302 , according to the real-time air pressure and the preset air pressure range, the forward rotation speed of the urea pump 102 is controlled, and the urea injector 103 is controlled to open.

[0069] Specifically, the control unit 107 controls the forward rotation speed of the urea pump 102 and controls the opening of the urea injector 103 according to the real-time air pressure and the preset air pressure range. Under the action of the urea pump 102, the urea solution in the urea tank 101 is transported to the urea injector 103, and the urea injector 103 injects the urea solution into the reactor 104. The reactor 104 contains a urea hydrolysis catalyst, and the pressure and temperature required for urea hydrolysis are maintained in the reactor 104. The urea solution in the reactor 104 reacts chemically with the urea hydrolysis catalyst to produce ammonia. The control unit 107 controls the rotation speed of the urea pump 102 and the speed at which the urea injector 103 sprays the urea solution into the reactor 104, so that the ammonia generated in the reactor 104 maintains a preset concentration, and sufficient ammonia enters the pressure stabilizing tank 105, so that the air pressure in the pressure stabilizing tank 105 is maintained within a preset pressure range, ensuring that the ammonia in the pressure stabilizing tank 105 can be smoothly injected into the post-treatment system 108 through the ammonia injector 106.

[0070] Step S303 , controlling the injection amount of the ammonia injector 106 according to the exhaust temperature, the concentration of nitrogen oxides and the preset nitrogen-oxygen conversion rate.

[0071] Specifically, the control unit 107 calculates the ammonia injection demand according to the exhaust temperature, the concentration of nitrogen oxides and the preset nitrogen oxygen conversion rate, and then performs ammonia injection according to the calculated ammonia injection demand.

[0072] It can be that the opening of the ammonia injector 106 is controlled according to the ammonia injection demand. The larger the ammonia injection demand is, the larger the opening of the ammonia injector 106 is controlled by the control unit 107; the smaller the ammonia injection demand is, the smaller the opening of the ammonia injector 106 is controlled by the control unit 107. In this way, the ammonia injector 106 injects an appropriate amount of ammonia to the post-treatment system 108, ensuring that the exhaust gas discharged by the vehicle meets the emission standards.

[0073] Alternatively, the opening time of the ammonia injector 106 is controlled according to the ammonia injection demand. The larger the determined ammonia injection demand is, the longer the opening time of the ammonia injector 106 is controlled by the control unit 107; the smaller the determined ammonia injection demand is, the shorter the opening time of the ammonia injector 106 is controlled by the control unit 107. In this way, the ammonia injector 106 injects an appropriate amount of ammonia to the post-treatment system 108, ensuring that the exhaust gas discharged by the vehicle meets the emission standards.

[0074] It should be noted that designers can set the specific value of the preset nitrogen oxygen conversion rate according to actual conditions.

[0075] The ammonia injection control method provided in the embodiment of the present application injects ammonia into the post-treatment system 108 to replace the original urea solution, which can effectively solve the problem that the vehicle exhaust gas does not meet the emission standards due to the crystallization of the urea solution.

[0076] In one embodiment of the present application, the ammonia injection control method further includes: when the vehicle is turned off, controlling the urea pump 102 to reverse, so that the urea injector 103 and the urea solution in the pipeline flow back to the urea tank 101 .

[0077] Specifically, when the vehicle is turned off, the control unit 107 controls the urea pump 102 to reverse, so that the urea solution in the urea injector 103 and the pipeline flows back to the urea tank 101, thereby preventing the urea solution from crystallizing and causing blockage of the urea injector 103 and the pipeline, and ensuring that when the vehicle is started again, the ammonia injection control system can still normally inject ammonia to the post-treatment system 108, thereby ensuring that the vehicle exhaust meets the emission standards.

[0078] In one embodiment of the present application, the ammonia injection control method further includes: when the vehicle is turned off, controlling the air compressor 109 to operate, injecting air into the reactor 104, so that the reactor 104, the pressure stabilizing tank 105, the ammonia injector 106 and the ammonia in the pipeline enter the post-treatment system 108.

[0079] Specifically, when the vehicle is turned off, the control unit 107 controls the air compressor 109 to work, injects air into the reactor 104, and causes the reactor 104, the pressure stabilizing tank 105, the ammonia injector 106, and the ammonia in the pipeline to enter the post-treatment system 108. The ammonia entering the post-treatment system 108 reacts chemically with the nitrogen oxides in the exhaust gas under the action of the post-treatment catalyst, so that the ammonia in the reactor 104, the pressure stabilizing tank 105, the ammonia injector 106, and the pipeline is consumed, preventing the ammonia from being discharged outside the vehicle to pollute the environment, thereby improving the safety of the ammonia injection control system.

[0080] The present application also provides a vehicle, including the above-mentioned ammonia injection control system. When the vehicle is in the starting state, the control unit 107 controls the urea pump 102 to rotate forward, and controls the urea injector 103 and the ammonia injector 106 to open. The urea solution in the urea tank 101 is injected into the reactor 104 by the urea injector 103 through the urea pump 102, and reacts with the catalyst in the reactor 104 to generate ammonia. The ammonia generated in the reactor 104 enters the pressure stabilizing tank 105, and the ammonia in the pressure stabilizing tank 105 is injected into the post-treatment system 108 by the ammonia injector 106 to reduce the nitrogen oxide gas. Injecting ammonia into the post-treatment system 108 to replace the original urea solution can effectively solve the problem that the vehicle exhaust gas does not meet the emission standards due to the crystallization of the urea solution.

[0081] When the vehicle is turned off, the control unit 107 controls the urea pump 102 to reverse, so that the urea solution in the urea injector 103 and the pipeline flows back to the urea tank 101, to prevent the urea solution from crystallizing and causing blockage of the urea injector 103 and the pipeline, to ensure that when the vehicle is started again, the ammonia injection control system can still normally inject ammonia to the post-treatment system 108, to ensure that the vehicle exhaust meets the emission standards.

[0082] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. An ammonia injection control system, characterized in that: The system comprises a urea tank, a urea pump, a urea injector, a reactor, a pressure stabilizing tank, an ammonia injector and a control unit; the urea tank is connected to the urea injector through the urea pump, and the injection port of the urea injector is arranged in the reactor; the reactor, the pressure stabilizing tank and the ammonia injector are connected in sequence, and the injection port of the ammonia injector is arranged on the post-treatment system; the control unit is electrically connected to the urea pump, the urea injector and the ammonia injector respectively; When the vehicle is in a starting state, the control unit controls the urea pump to rotate forward, and controls the urea injector and the ammonia injector to open, and the urea solution in the urea tank is injected into the reactor by the urea injector through the urea pump, and reacts with the catalyst in the reactor to generate ammonia; The ammonia gas produced in the reactor enters the pressure stabilizing tank; the ammonia gas in the pressure stabilizing tank is injected into the post-treatment system by the ammonia injector; When the vehicle is turned off, the control unit controls the urea pump to reverse, so that the urea solution in the urea injector and the pipeline flows back to the urea tank; The ammonia injection control system further includes a pressure acquisition unit, a temperature acquisition unit and a nitrogen oxide detection unit, wherein the pressure acquisition unit, the temperature acquisition unit and the nitrogen oxide detection unit are all electrically connected to the control unit; When the vehicle is in a starting state, the pressure acquisition unit is used to acquire the real-time air pressure in the pressure stabilizing tank, the temperature acquisition unit is used to acquire the exhaust temperature of the engine, the nitrogen oxide detection unit is used to acquire the concentration of nitrogen oxides in the engine exhaust, and the control unit is used to control the forward rotation speed of the urea pump and control the opening of the urea injector according to the real-time air pressure and a preset air pressure range; the control unit is also used to control the injection amount of the ammonia injector according to the exhaust temperature, the concentration of nitrogen oxides and a preset nitrogen oxide conversion rate.

2. The ammonia injection control system according to claim 1, characterized in that: The ammonia injection control system further comprises an air compressor, the air compressor is in communication with the reactor, and the air compressor is electrically connected to the control unit; When the vehicle is turned off, the control unit controls the air compressor to operate and inject air into the reactor, so that the reactor, the pressure stabilizing tank, the ammonia injector and the ammonia in the pipeline enter the post-treatment system.

3. The ammonia injection control system according to claim 2, characterized in that: The ammonia injection control system further includes an air filter, which is communicated with an air inlet of the air compressor.

4. The ammonia injection control system according to claim 1, characterized in that: The ammonia injection control system further includes a pressure relief valve, which is connected in series between the urea tank and the pressure stabilizing tank.

5. The ammonia injection control system according to claim 1, characterized in that: The ammonia injection control system further comprises a pressure reducing valve, which is connected in series between the reactor and the pressure stabilizing tank, and is electrically connected to the control unit.

6. The ammonia injection control system according to claim 5, characterized in that: The ammonia injection control system also includes a shut-off valve, which is connected in series between the pressure reducing valve and the pressure stabilizing tank, and is electrically connected to the control unit. The shut-off valve is used to open or close according to a control signal from the control unit.

7. An ammonia injection control method, characterized in that: Applicable to the ammonia injection control system according to any one of claims 1 to 6, the ammonia injection control method comprises: When the vehicle is in the starting state, the real-time air pressure in the pressure regulating box, the exhaust temperature of the engine and the concentration of nitrogen oxides in the engine exhaust are obtained; According to the real-time air pressure and the preset air pressure range, the forward rotation speed of the urea pump is controlled, and the opening of the urea injector is controlled; The injection amount of the ammonia injector is controlled according to the exhaust temperature, the concentration of the nitrogen oxides and a preset nitrogen oxygen conversion rate.

8. The ammonia injection control method according to claim 7, characterized in that: The ammonia injection control method further comprises: When the vehicle is turned off, the urea pump is controlled to reverse, so that the urea solution in the urea injector and the pipeline flows back to the urea tank.

9. A vehicle, characterized in that: The invention comprises the ammonia injection control system as described in any one of claims 1 to 6.

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