A fault diagnosis method and device of a tail gas aftertreatment system, a vehicle and a medium

Abstract

The embodiment of the application discloses a tail gas aftertreatment system fault diagnosis method, device, vehicle and medium, the method comprises the following steps: when it is detected that the fault diagnosis condition is met, controlling the tail gas aftertreatment system to flow in a plurality of working states according to a preset state flow sequence; obtaining a target state in which the tail gas aftertreatment system currently locates and at least one preset judgment condition corresponding to the target state; according to the preset judgment condition, performing on-off control on the pressure regulating stop valve and the ammonia gas metering valve, determining the credibility of the ammonia tank pressure and / or the ammonia gas pressure collected in the target state through at least one of the ammonia tank pressure and the ammonia gas pressure; if it is determined that the ammonia tank pressure or the ammonia gas pressure is not credible according to the credibility of the ammonia tank pressure and / or the ammonia gas pressure in at least one target state, ending the fault detection process and generating a detection result, which ensures the ammonia gas injection precision and improves the tail gas treatment effect.

Description

Technical Field

[0001] This invention relates to the field of engine exhaust aftertreatment technology, and in particular to a fault diagnosis method, device, vehicle, and medium for an exhaust aftertreatment system. Background Technology

[0002] As vehicle emission standards become increasingly stringent, the emission limits for nitrogen oxides in exhaust gases are becoming more and more stringent. How to convert nitrogen oxides in exhaust gases into harmless substances to the greatest extent possible has become one of the key issues in the field of exhaust gas after-treatment.

[0003] In existing technologies, solid-state selective catalytic reduction (SSCR) technology is commonly used for exhaust gas treatment. Specifically, ammonia gas produced from solid ammonia can be used as a reducing agent to chemically react with nitrogen oxides in the exhaust gas, producing pollution-free nitrogen and water.

[0004] However, as the usage time of the exhaust gas aftertreatment system increases, the possibility of malfunctions in the exhaust gas aftertreatment system becomes more and more likely. Existing technologies cannot detect system malfunctions in a timely manner, resulting in inaccurate ammonia injection and poor exhaust gas treatment effect. Summary of the Invention

[0005] This invention provides a fault diagnosis method, device, vehicle, and medium for an exhaust gas aftertreatment system, which can ensure the accuracy of ammonia injection and improve the exhaust gas treatment effect.

[0006] Firstly, a fault diagnosis method for an exhaust gas aftertreatment system is provided, applied to the exhaust gas aftertreatment system, which includes: an ammonia storage tank, an ammonia gas rail, a pressure regulating shut-off valve, an ammonia metering valve, a controller, an ammonia tank pressure sensor, and an ammonia gas pressure sensor; the ammonia storage tank is used to store ammonia; the pressure regulating shut-off valve is used to control whether ammonia from the ammonia storage tank is input into the ammonia gas rail; the ammonia metering valve is used to inject ammonia from the ammonia gas rail; the ammonia tank pressure sensor is used to monitor the ammonia pressure in the ammonia storage tank; and the ammonia pressure sensor is used to monitor the ammonia pressure in the ammonia gas rail.

[0007] This method is executed by the controller and includes:

[0008] When the fault diagnosis conditions are met, the exhaust gas aftertreatment system is controlled to switch between multiple working states according to a preset state transition sequence. The state transition sequence includes: initialization state, cold start state, ammonia filling state, ammonia filling diagnosis state, test injection state, and injection state.

[0009] Obtain the current target state of the exhaust gas aftertreatment system, and at least one preset judgment condition corresponding to the target state;

[0010] According to the preset judgment conditions corresponding to the target state, the switch control of the pressure regulating shut-off valve and the switch control of the ammonia metering valve are executed. At least one of the following is collected: the ammonia tank pressure is collected by the ammonia tank pressure sensor and the ammonia pressure is collected by the ammonia gas pressure sensor. The reliability of the ammonia tank pressure and / or ammonia gas pressure collected under the target state is determined.

[0011] During the fault detection process, if, based on the reliability of the ammonia tank pressure and / or ammonia gas pressure under at least one target condition, it is determined that the unreliable diagnostic conditions for the ammonia tank pressure or ammonia gas pressure are met, the fault detection process ends and the detection results are generated.

[0012] Optionally, when the fault diagnosis conditions are met, the exhaust gas aftertreatment system is controlled to transition through multiple operating states according to a preset state transition sequence, including: when the fault diagnosis conditions are met, the exhaust gas aftertreatment system is powered on and enters the initialization state; in the initialization state, if the temperature detection value at at least one detection point meets the preset temperature detection conditions, the exhaust gas aftertreatment system enters the cold start state; in the cold start state, if the ammonia tank pressure meets the preset pressure threshold, the ammonia storage tank is filled with ammonia, and the exhaust gas aftertreatment system enters the ammonia filling state; after entering the ammonia filling state, if the ammonia tank pressure and ammonia pressure meet the diagnosis conditions, the exhaust gas aftertreatment system enters the ammonia filling diagnosis state; after the ammonia filling is completed or the ammonia filling diagnosis is passed, the exhaust gas aftertreatment system enters the test injection state, and a set number of test injection operations are performed by controlling the opening and closing of the ammonia metering valve; after the test injection operation is completed, the exhaust gas aftertreatment system enters the injection state.

[0013] Optionally, according to preset judgment conditions corresponding to the target state, the on / off control of the pressure regulating shut-off valve and the on / off control of the ammonia metering valve are executed. At least one of the following is used: collecting ammonia tank pressure through an ammonia tank pressure sensor and collecting ammonia pressure through an ammonia gas pressure sensor. The reliability of the collected ammonia tank pressure and / or ammonia gas pressure under the target state is determined, including: when the target state is ammonia filling state, collecting ammonia tank pressure through an ammonia tank pressure sensor and collecting ammonia gas pressure through an ammonia gas pressure sensor; when the ammonia tank pressure is less than a first preset ammonia gas pressure, obtaining the target ammonia tank pressure in the ammonia storage tank after a preset duration, and determining the pressure change in the ammonia storage tank based on the ammonia tank pressure and the target ammonia tank pressure; if the ammonia tank pressure is less than a second preset ammonia gas pressure, and the pressure change is greater than or equal to a preset pressure difference, then the ammonia tank pressure is determined to be reliable; if the target ammonia tank pressure is greater than or equal to the second preset ammonia gas pressure, or the pressure change is less than the preset pressure difference, then the ammonia tank pressure is determined to be unreliable.

[0014] Optionally, according to preset judgment conditions corresponding to the target state, the on / off control of the pressure regulating shut-off valve and the on / off control of the ammonia metering valve are executed. At least one of the following is used: collecting ammonia tank pressure via an ammonia tank pressure sensor and collecting ammonia pressure via an ammonia gas pressure sensor. The reliability of the collected ammonia tank pressure and / or ammonia gas pressure under the target state is determined, including: when the target state is an ammonia filling diagnostic state, collecting ammonia tank pressure via an ammonia tank pressure sensor and collecting ammonia gas pressure via an ammonia gas pressure sensor; when the ammonia tank pressure is greater than or equal to a first preset ammonia gas pressure, and the ammonia gas pressure is less than a first preset ammonia gas pressure, controlling the pressure regulating shut-off valve and the ammonia metering valve to open; after a preset diagnostic time, obtaining the ammonia tank pressure difference during the start and end times of the diagnostic time, and the average ammonia tank pressure during the diagnostic time, and obtaining the ammonia gas rail pressure during the start and end times of the diagnostic time. The ammonia pressure difference and the average ammonia pressure during the diagnostic period are used as the basis for determining the ammonia tank pressure. If the ammonia tank pressure difference is less than the first preset pressure difference, the ammonia pressure difference is less than the second preset pressure difference, and the average ammonia tank pressure and the average ammonia pressure are less than the third preset pressure difference, then the ammonia tank pressure under the ammonia filling diagnostic state is determined to be unreliable. If the ammonia tank pressure difference is less than the first preset pressure difference, and the ammonia pressure difference is greater than or equal to the second preset pressure difference, then the ammonia tank pressure under the ammonia filling diagnostic state is determined to be unreliable, and the ammonia pressure is reliable. If the ammonia tank pressure difference is greater than or equal to the first preset pressure difference, and the ammonia pressure difference is less than the second preset pressure difference, then the ammonia tank pressure under the ammonia filling diagnostic state is determined to be reliable, and the ammonia pressure is unreliable. If the ammonia tank pressure difference is greater than or equal to the first preset pressure difference, and the ammonia pressure difference is greater than or equal to the second preset pressure difference, then both the ammonia tank pressure and the ammonia pressure under the ammonia filling diagnostic state are determined to be reliable.

[0015] Optionally, according to preset judgment conditions corresponding to the target state, the on / off control of the pressure regulating shut-off valve and the ammonia metering valve is executed. At least one of the following is used: collecting ammonia tank pressure via an ammonia tank pressure sensor and collecting ammonia pressure via an ammonia gas pressure sensor. The reliability of the collected ammonia tank pressure and / or ammonia pressure under the target state is determined, including: when the target state is a test injection state, collecting ammonia pressure via an ammonia pressure sensor; controlling the ammonia metering valve to inject ammonia from the ammonia gas rail according to a preset single injection quantity and preset injection frequency. The ammonia pressure is collected again by the ammonia pressure sensor to obtain the pressure difference of ammonia in the ammonia gas track before and after ammonia injection; the expected change in ammonia is determined based on the preset single injection volume and preset number of injections; the actual reduction of ammonia in the ammonia gas track is determined based on the ammonia pressure difference, and the ammonia change ratio is determined based on the actual reduction of ammonia and the expected change in ammonia; if the ammonia change ratio is less than a first preset ratio threshold, the ammonia pressure is determined to be unreliable; if the ammonia change ratio is greater than or equal to the first preset ratio threshold, the ammonia pressure is determined to be reliable.

[0016] Optionally, according to preset judgment conditions corresponding to the target state, the on / off control of the pressure regulating shut-off valve and the on / off control of the ammonia metering valve are executed. At least one of the following is used: collecting ammonia tank pressure via an ammonia tank pressure sensor and collecting ammonia pressure via an ammonia gas pressure sensor. The reliability of the collected ammonia tank pressure and / or ammonia pressure under the target state is determined, including: when the target state is the injection state, collecting ammonia tank pressure via an ammonia tank pressure sensor and collecting ammonia pressure via an ammonia gas pressure sensor; when the ammonia tank pressure is greater than or equal to a first preset ammonia pressure and less than a third preset ammonia pressure, controlling the pressure regulating shut-off valve to remain open; obtaining the actual injection volume of ammonia for each injection, and counting the first number of ammonia injections where the actual injection volume is less than a first preset injection volume threshold; obtaining the average ammonia pressure and the average ammonia tank pressure during each ammonia injection process, and counting the actual injection volume... The number of ammonia injections is determined as follows: if the actual injection volume is less than the first preset injection volume threshold, and the difference between the average ammonia pressure and the average ammonia tank pressure during the ammonia injection process is less than the preset deviation threshold; if the ratio between the first and second ammonia injections is less than the second preset proportion threshold, then both the ammonia tank pressure and the ammonia pressure are determined to be unreliable; if the ammonia tank pressure is greater than the third preset ammonia pressure within a preset time period, then the number of third ammonia injections is counted when the actual injection volume is within the preset injection volume range; the number of fourth ammonia injections is counted when the actual injection volume is within the preset injection volume range, the pressure difference in the ammonia storage tank before and after injection is less than the first preset pressure difference, and the pressure difference in the ammonia gas rail before and after injection is greater than the second preset pressure difference; if the ratio between the third and fourth ammonia injections is greater than or equal to the second preset proportion threshold, then the ammonia tank pressure is determined to be unreliable.

[0017] The fifth ammonia injection is defined as follows: if the actual injection volume is within the preset injection volume range, the pressure difference in the ammonia storage tank before and after injection is greater than the first preset pressure difference, and the pressure difference in the ammonia gas rail before and after injection is less than the second preset pressure difference; if the ratio between the third and fifth ammonia injection times is greater than or equal to the second preset proportion threshold, then the ammonia pressure is determined to be unreliable. The sixth ammonia injection is defined as follows: if the actual injection volume is within the preset injection volume range, the pressure difference in the ammonia storage tank before and after injection is greater than the first preset pressure difference, and the pressure difference in the ammonia gas rail before and after injection is greater than the second preset pressure difference; if the ratio between the third and sixth ammonia injection times is greater than or equal to the third preset proportion threshold, then both the ammonia tank pressure and the ammonia pressure are determined to be reliable; if the ratio between the third and sixth ammonia injection times is less than the third preset proportion threshold, then both the ammonia tank pressure and the ammonia pressure are determined to be unreliable.

[0018] Optionally, during the fault detection process, if, based on the reliability of the ammonia tank pressure and / or ammonia gas pressure under at least one target state, it is determined that the unreliable diagnostic condition for ammonia tank pressure or ammonia gas pressure is met, the fault detection process ends and a detection result is generated, including: if the ammonia tank pressure is unreliable under the initialization state and the ammonia tank pressure under the ammonia gas filling state, then the unreliable diagnostic condition for ammonia tank pressure is determined to be met; if the ammonia tank pressure under the ammonia gas filling diagnostic state is unreliable, then the unreliable diagnostic condition for ammonia tank pressure is determined to be met; if the ammonia gas pressure under both the test injection state and the injection state is unreliable, then the unreliable diagnostic condition for ammonia gas pressure is determined to be met.

[0019] Secondly, a fault diagnosis device for an exhaust gas aftertreatment system is provided, which is applied to the exhaust gas aftertreatment system. The exhaust gas aftertreatment system includes: an ammonia storage tank, an ammonia gas rail, a pressure regulating shut-off valve, an ammonia metering valve, a controller, an ammonia tank pressure sensor, and an ammonia gas pressure sensor. The ammonia storage tank is used to store ammonia gas; the pressure regulating shut-off valve is used to control whether ammonia gas from the ammonia storage tank is input into the ammonia gas rail; the ammonia metering valve is used to inject ammonia gas into the ammonia gas rail; the ammonia tank pressure sensor is used to monitor the ammonia pressure in the ammonia storage tank; and the ammonia pressure sensor is used to monitor the ammonia pressure in the ammonia gas rail.

[0020] The device is executed by a controller and includes:

[0021] The state transition module is used to control the exhaust gas aftertreatment system to transition through multiple working states according to a preset state transition sequence when the fault diagnosis conditions are detected. The state transition sequence includes: initialization state, cold start state, ammonia filling state, ammonia filling diagnosis state, test injection state, and injection state.

[0022] The judgment condition acquisition module is used to acquire the current target state of the exhaust gas aftertreatment system and at least one preset judgment condition corresponding to the target state.

[0023] The confidence status determination module is used to perform on / off control of the pressure regulating shut-off valve and the ammonia metering valve according to the preset judgment conditions corresponding to the target state, and to determine the confidence status of the ammonia tank pressure and / or ammonia pressure collected under the target state by collecting at least one of the ammonia tank pressure sensor and the ammonia pressure sensor.

[0024] The test result generation module is used to terminate the fault detection process and generate test results if, during the fault detection process, it is determined, based on the reliability of the ammonia tank pressure and / or ammonia gas pressure under at least one target state, that the unreliable diagnostic conditions for ammonia tank pressure or ammonia gas pressure are met.

[0025] Thirdly, a vehicle is provided, the vehicle comprising:

[0026] The exhaust gas aftertreatment system as described in any embodiment of the present invention; and

[0027] At least one memory is included, and the exhaust aftertreatment system includes a controller, with the memory communicatively connected to the controller; wherein...

[0028] The memory stores a computer program that can be executed by at least one controller, such that the at least one controller is able to perform the fault diagnosis method of the exhaust gas aftertreatment system according to any embodiment of the present invention.

[0029] The technical solution of this invention determines the fault status of the exhaust gas aftertreatment system based on the reliability of the ammonia tank pressure and ammonia gas pressure, avoiding the situation where the ammonia injection volume is determined based on the faulty exhaust gas aftertreatment system, which leads to poor ammonia injection accuracy and improves the exhaust gas treatment effect.

[0030] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of an exhaust gas aftertreatment system provided in Embodiment 1 of the present invention;

[0033] Figure 2 This is a flowchart of a fault diagnosis method for an exhaust gas aftertreatment system according to Embodiment 1 of the present invention;

[0034] Figure 3 This is a flowchart of another fault diagnosis method for an exhaust gas aftertreatment system provided in Embodiment 2 of the present invention;

[0035] Figure 4 This is a flowchart of a method for diagnosing the reliability of ammonia tank pressure according to an embodiment of the present invention;

[0036] Figure 5 This is a flowchart of an ammonia pressure reliability diagnosis method provided by an embodiment of the present invention;

[0037] Figure 6This is a schematic diagram of a preferred exhaust gas aftertreatment system according to an embodiment of the present invention.

[0038] Figure 7 This is a flowchart of a preferred fault diagnosis method for an exhaust gas aftertreatment system according to an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the structure of a fault diagnosis device for an exhaust gas aftertreatment system according to Embodiment 3 of the present invention;

[0040] Figure 9 This is a structural schematic diagram of a vehicle implementing the fault diagnosis method of the exhaust gas aftertreatment system according to an embodiment of the present invention. Detailed Implementation

[0041] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0043] Example 1

[0044] Figure 1 This is a schematic diagram of an exhaust gas aftertreatment system according to Embodiment 1 of the present invention. This embodiment can be applied to the situation of aftertreatment of engine exhaust gas.

[0045] like Figure 1 As shown, the exhaust gas aftertreatment system 11 disclosed in this embodiment includes: an ammonia storage tank 101, an ammonia gas rail 102, a pressure regulating shut-off valve 103, an ammonia metering valve 104, a controller 105, an ammonia tank pressure sensor 106, and an ammonia pressure sensor 107.

[0046] Specifically, the ammonia storage tank 101 can be used to store ammonia gas, and the pressure regulating shut-off valve 103 can be used to control whether the ammonia gas in the ammonia storage tank 101 is input into the ammonia gas rail 102. The ammonia metering valve 104 can be used to inject ammonia gas into the ammonia gas rail 102, and the ammonia tank pressure sensor 106 can be used to monitor the ammonia pressure in the ammonia storage tank 101 and send the ammonia pressure in the ammonia storage tank 101 to the controller 105. The ammonia pressure sensor 107 can be used to monitor the ammonia pressure in the ammonia gas rail 102 and send the ammonia pressure in the ammonia gas rail 102 to the controller 105.

[0047] Figure 2 This is a flowchart of a fault diagnosis method for an exhaust gas aftertreatment system according to Embodiment 1 of the present invention. Figure 2 As shown, this embodiment discloses a fault diagnosis method for an exhaust gas aftertreatment system. The method is executed by the controller 105 and specifically includes the following steps:

[0048] S210. When the fault diagnosis conditions are detected, the exhaust gas aftertreatment system is controlled to switch between multiple working states according to the preset state transition sequence.

[0049] In this embodiment, the state transition sequence includes: initialization state, cold start state, ammonia filling state, ammonia filling diagnostic state, test injection state, and injection state. The ammonia filling diagnostic state is not a necessary transition state.

[0050] Specifically, the initialization state can be the controller power-on state, and the cold start state can be the engine start state. The ammonia filling state can be the state where exhaust gas is controlled to enter the ammonia storage tank to utilize the waste heat of the exhaust gas to pyrolyze the solid ammonia in the storage tank to produce ammonia gas. The ammonia filling diagnostic state can be the stage where the ammonia tank pressure and the reliability of the ammonia gas pressure are diagnosed after ammonia filling failure.

[0051] In one specific implementation, when there are no circuit faults in the ammonia tank pressure sensor, ammonia pressure sensor, ammonia metering valve, and pressure regulating shut-off valve in the exhaust gas aftertreatment system, the exhaust gas aftertreatment system can be controlled to operate according to a preset state sequence. The types of circuit faults can include short circuits and open circuits.

[0052] S220. Obtain the current target state of the exhaust gas aftertreatment system and at least one preset judgment condition corresponding to the target state.

[0053] In this embodiment, the target state can be any one of the following: initialization state, cold start state, ammonia filling state, ammonia filling diagnostic state, test injection state, and injection state.

[0054] Taking the initialization state as an example, one of the preset judgment conditions corresponding to the initialization state can be that the proportion of remaining ammonia in the ammonia storage tank is less than a preset remaining amount proportion, and the pressure in the ammonia storage tank is less than a first preset ammonia pressure. The proportion of remaining ammonia in the ammonia storage tank can be the ratio between the amount of remaining ammonia in the ammonia storage tank and the preset maximum storage capacity of the ammonia tank. The preset remaining amount proportion can be determined based on historical experience, for example, 90%. A third preset judgment condition corresponding to the initialization state can be that the proportion of remaining ammonia in the ammonia storage tank is greater than or equal to the preset remaining amount proportion.

[0055] S230. According to the preset judgment conditions corresponding to the target state, perform the switching control of the pressure regulating shut-off valve and the switching control of the ammonia metering valve, and collect at least one of the ammonia tank pressure and the ammonia pressure through the ammonia tank pressure sensor, and determine the reliability of the ammonia tank pressure and / or ammonia pressure collected under the target state.

[0056] In this embodiment, the preset judgment conditions can be used to determine the reliability of the ammonia tank pressure and / or ammonia gas pressure.

[0057] In one specific implementation, a preset judgment condition used only to determine the reliability of the ammonia tank pressure can be designated as a first type of judgment condition, a preset judgment condition used only to determine the reliability of the ammonia gas pressure can be designated as a second type of judgment condition, and a preset judgment condition used to determine the reliability of both the ammonia tank pressure and the ammonia gas pressure can be designated as a third type of judgment condition. Specifically, the first type of judgment condition only limits the ammonia tank pressure, the second type of judgment condition only limits the ammonia gas pressure, and the third type of judgment condition limits both the ammonia tank pressure and the ammonia gas pressure.

[0058] When the ammonia tank pressure meets both the first and third criteria, the ammonia tank pressure under the target state is determined to be reliable. When the ammonia tank pressure does not meet either the first or second criteria, the ammonia tank pressure under the target state is determined to be unreliable. Correspondingly, when the ammonia gas pressure meets both the second and third criteria, the ammonia gas pressure under the target state is determined to be reliable. When the ammonia gas pressure does not meet either the second or third criteria, the ammonia gas pressure under the target state is determined to be unreliable.

[0059] Continuing from the previous example, the amount of remaining ammonia in the ammonia storage tank can be determined based on the ammonia tank pressure. Then, the proportion of remaining ammonia in the storage tank can be determined based on the amount of remaining ammonia and the preset maximum storage capacity of the ammonia tank. When the proportion of remaining ammonia in the storage tank is less than the preset remaining proportion, and the ammonia tank pressure is less than the first preset ammonia pressure, the ammonia tank pressure under the target condition is deemed reliable.

[0060] When the proportion of remaining ammonia in the ammonia storage tank is greater than or equal to the preset remaining proportion, the reliability of the ammonia tank pressure under the target condition is pending. At this time, the reliability of the ammonia tank pressure sensor is also pending, as is the malfunction of the exhaust gas aftertreatment system.

[0061] S240. During the fault detection process, if it is determined, based on the reliability of the ammonia tank pressure and / or ammonia gas pressure under at least one target state, that the unreliable diagnostic conditions for the ammonia tank pressure or ammonia gas pressure are met, then the fault detection process ends and a detection result is generated.

[0062] In this embodiment, the detection results may include exhaust after-treatment system malfunction, exhaust after-treatment system not malfunction, and exhaust after-treatment system malfunction status pending.

[0063] In this step, specifically, the malfunction of the ammonia tank pressure sensor and the ammonia gas pressure sensor can be determined based on the reliability of the ammonia tank pressure and / or ammonia gas pressure under at least one target condition. Then, the malfunction of the exhaust gas aftertreatment system can be determined based on the malfunction of each sensor.

[0064] For example, if the target state is an ammonia-filled state, and either the ammonia tank pressure or the ammonia pressure is unreliable, then the sensor corresponding to the unreliable pressure can be determined to be unreliable, thus indicating a fault in the exhaust aftertreatment system. If the target state is an injection state, and the ammonia pressure is unreliable during the test injection state, then the reliability of the ammonia pressure sensor is uncertain, and the fault status of the exhaust aftertreatment system is uncertain.

[0065] If the target state is the injection state, then if the ammonia pressure under the test injection state is unreliable, and the ammonia pressure under the injection state is also unreliable, then it can be determined that the ammonia pressure sensor is unreliable, thereby determining that the exhaust gas aftertreatment system is faulty.

[0066] Optionally, a system fault alarm can be issued after a fault in the exhaust aftertreatment system is determined.

[0067] The technical solution of this embodiment, when a fault diagnosis condition is detected, controls the exhaust gas aftertreatment system to transition through multiple operating states according to a preset state transition sequence. This state transition sequence includes: initialization state, cold start state, ammonia filling state, ammonia filling diagnosis state, test injection state, and injection state. The system acquires the current target state of the exhaust gas aftertreatment system and at least one preset judgment condition corresponding to the target state. Based on the preset judgment condition corresponding to the target state, it executes on / off control of the pressure regulating valve and the ammonia metering valve, and collects at least one of the following: ammonia tank pressure via an ammonia tank pressure sensor and ammonia pressure via an ammonia gas pressure sensor, determining the reliability of the ammonia tank pressure and / or ammonia pressure collected under the target state. During the fault detection process, if, based on the reliability of the ammonia tank pressure and / or ammonia pressure under at least one target state, it is determined that an unreliable diagnostic condition for ammonia tank pressure or ammonia pressure is met, the fault detection process ends and a detection result is generated. This technical means solves the problem in existing technologies where system faults cannot be detected in a timely manner, leading to inaccurate ammonia injection volume and poor exhaust gas treatment effect. By verifying the reliability of ammonia pressure, system malfunctions can be identified, avoiding the use of faulty exhaust gas aftertreatment systems. The ammonia injection volume can also be determined, ensuring ammonia injection accuracy and improving exhaust gas treatment efficiency.

[0068] Example 2

[0069] The exhaust gas aftertreatment system disclosed in this embodiment includes an ammonia storage tank, an ammonia gas rail, a pressure regulating shut-off valve, an ammonia metering valve, a controller, an ammonia tank pressure sensor, an ammonia gas pressure sensor, an ammonia tank temperature sensor, and an ammonia gas temperature sensor.

[0070] Figure 3 This is a flowchart of another fault diagnosis method for an exhaust gas aftertreatment system according to Embodiment 2 of the present invention. This embodiment is a further refinement of the above technical solution, and the technical solution in this embodiment can be combined with various optional solutions in one or more of the above embodiments. Figure 3 As shown, the method includes:

[0071] S310. When the fault diagnosis conditions are detected, the exhaust gas aftertreatment system is powered on and the exhaust gas aftertreatment system is confirmed to enter the initialization state.

[0072] S320. In the initialization state, if it is determined that the temperature detection value of at least one detection point meets the preset temperature detection conditions, then the exhaust gas aftertreatment system is determined to enter the cold start state.

[0073] In one specific implementation, the ammonia tank temperature can be collected by an ammonia tank temperature sensor, and the ammonia gas temperature can be collected by an ammonia gas temperature sensor. An upper temperature limit and a lower temperature limit are determined from the ammonia tank temperature and the ammonia gas temperature. If both the collected ammonia tank temperature and the ammonia gas temperature are greater than a first preset temperature threshold, and the difference between the upper temperature limit and the lower temperature limit is less than or equal to a second preset temperature threshold, then the exhaust gas aftertreatment system is determined to have entered the cold start state.

[0074] S330. In the cold start state, if the pressure of the ammonia tank is detected to meet the preset pressure threshold, the ammonia storage tank is filled with ammonia, and the exhaust gas after-treatment system is confirmed to enter the ammonia filling state.

[0075] In one specific implementation, the ammonia storage tank can be filled with ammonia gas after the engine has started and the ammonia tank pressure is less than the first preset ammonia gas pressure.

[0076] In an optional embodiment of the present invention, when the target state is an ammonia-filled state, the ammonia tank pressure is collected by an ammonia tank pressure sensor, and the ammonia pressure is collected by an ammonia gas pressure sensor; when the ammonia tank pressure is less than a first preset ammonia gas pressure, the target ammonia tank pressure in the ammonia storage tank after a preset duration is obtained, and the pressure change in the ammonia storage tank is determined based on the ammonia tank pressure and the target ammonia tank pressure; if the ammonia tank pressure is less than a second preset ammonia gas pressure, and the pressure change is greater than or equal to a preset pressure difference, then the ammonia tank pressure is determined to be reliable; if the target ammonia tank pressure is greater than or equal to the second preset ammonia gas pressure, or the pressure change is less than the preset pressure difference, then the ammonia tank pressure is determined to be unreliable.

[0077] In this embodiment, the preset duration can be determined based on the initial pressure and initial temperature of the ammonia storage tank.

[0078] For example, if the preset pressure difference is 20 kPa and the second preset ammonia pressure is 120 kPa, and the target ammonia tank pressure is less than 120 kPa, and the pressure change is greater than or equal to 20 kPa, then the ammonia tank pressure is determined to be unreliable.

[0079] S340. After entering the ammonia filling state, if the ammonia tank pressure and ammonia pressure are detected to meet the diagnostic conditions, the exhaust gas aftertreatment system is determined to have entered the ammonia filling diagnostic state.

[0080] In one specific implementation, the exhaust gas aftertreatment system can be determined to enter the ammonia filling diagnostic state when the ammonia tank pressure is greater than or equal to the first preset ammonia pressure and the ammonia pressure is less than the first preset ammonia pressure.

[0081] In an optional embodiment of the present invention, according to preset judgment conditions corresponding to the target state, the on / off control of the pressure regulating shut-off valve and the on / off control of the ammonia metering valve are executed. At least one of the following is used: collecting ammonia tank pressure via an ammonia tank pressure sensor and collecting ammonia pressure via an ammonia gas pressure sensor. The reliability of the collected ammonia tank pressure and / or ammonia gas pressure under the target state is determined. This includes: when the target state is an ammonia filling diagnostic state, collecting ammonia tank pressure via an ammonia tank pressure sensor and collecting ammonia gas pressure via an ammonia gas pressure sensor; when the ammonia tank pressure is greater than or equal to a first preset ammonia gas pressure, and the ammonia gas pressure is less than the first preset ammonia gas pressure, controlling the pressure regulating shut-off valve and the ammonia metering valve to open; after a preset diagnostic time, obtaining the ammonia tank pressure difference between the storage tank and the ammonia tank at the start and end times of the diagnostic time, and the average ammonia tank pressure during the diagnostic time, and obtaining the ammonia gas rail during the diagnostic time. The ammonia pressure difference during the start and end of the diagnostic period, and the average ammonia pressure during the diagnostic period; if the ammonia tank pressure difference is less than the first preset pressure difference, the ammonia pressure difference is less than the second preset pressure difference, and the average ammonia tank pressure and the average ammonia pressure are less than the third preset pressure difference, then the ammonia tank pressure under the ammonia filling diagnostic state is determined to be unreliable; if the ammonia tank pressure difference is less than the first preset pressure difference, and the ammonia pressure difference is greater than or equal to the second preset pressure difference, then the ammonia tank pressure under the ammonia filling diagnostic state is determined to be unreliable, and the ammonia pressure is reliable; if the ammonia tank pressure difference is greater than or equal to the first preset pressure difference, and the ammonia pressure difference is less than the second preset pressure difference, then the ammonia tank pressure under the ammonia filling diagnostic state is determined to be reliable, and the ammonia pressure is unreliable; if the ammonia tank pressure difference is greater than or equal to the first preset pressure difference, and the ammonia pressure difference is greater than or equal to the second preset pressure difference, then both the ammonia tank pressure and the ammonia pressure under the ammonia filling diagnostic state are determined to be reliable.

[0082] Figure 4 This is a flowchart of a method for diagnosing the reliability of ammonia tank pressure according to an embodiment of the present invention.

[0083] For example, such as Figure 4 As shown, under the conditions of a first preset pressure difference of 7 kPa, a second preset pressure difference of 5 kPa, and a third preset pressure difference of 10 kPa, if the ammonia tank pressure difference is less than 7 kPa, the ammonia gas pressure difference is greater than or equal to 5 kPa, and the average ammonia tank pressure and the average ammonia gas pressure are less than 10 kPa, then the ammonia tank pressure under the ammonia filling diagnostic state is determined to be unreliable. If the ammonia tank pressure difference is less than 7 kPa, and the ammonia gas pressure difference is greater than or equal to 5 kPa, then the ammonia tank pressure under the ammonia filling diagnostic state is determined to be unreliable, and the ammonia gas pressure is reliable. If the ammonia tank pressure difference is greater than or equal to 7 kPa, and the ammonia gas pressure difference is less than 5 kPa, then the ammonia tank pressure under the ammonia filling diagnostic state is determined to be reliable, and the ammonia gas pressure is unreliable. If the ammonia tank pressure difference is greater than or equal to 7 kPa, and the ammonia gas pressure difference is greater than or equal to 5 kPa, then both the ammonia tank pressure and the ammonia gas pressure are determined to be reliable under the ammonia filling diagnostic state.

[0084] S350: After confirming that the ammonia filling is complete or the ammonia filling diagnosis is passed, the exhaust gas aftertreatment system is confirmed to enter the test injection state, and the test injection operation is performed a set number of times by controlling the opening and closing of the ammonia metering valve.

[0085] Specifically, in this step, the exhaust gas aftertreatment system can be determined to enter the test injection state when both the ammonia tank pressure and the ammonia gas pressure are greater than or equal to the first preset ammonia gas pressure. Alternatively, the exhaust gas aftertreatment system can be controlled to enter the test injection state after confirming that both the ammonia tank pressure and the ammonia gas pressure are reliable during the ammonia filling diagnostic state.

[0086] In an optional embodiment of the present invention, when the target state is a test injection state, the ammonia pressure is collected by an ammonia pressure sensor; the ammonia metering valve is controlled to inject ammonia into the ammonia gas rail according to a preset single injection amount and a preset number of injections, and the ammonia pressure is collected again by the ammonia pressure sensor to obtain the ammonia pressure difference in the ammonia gas rail before and after ammonia injection; the expected ammonia change is determined according to the preset single injection amount and the preset number of injections; the actual reduction of ammonia in the ammonia gas rail is determined according to the ammonia pressure difference, and the ammonia change ratio is determined according to the actual reduction of ammonia and the expected ammonia change; if the ammonia change ratio is less than a first preset ratio threshold, the ammonia pressure is determined to be unreliable; if the ammonia change ratio is greater than or equal to the first preset ratio threshold, the ammonia pressure is determined to be reliable.

[0087] In one specific implementation, the expected change in ammonia gas can be determined based on the product of a preset single injection volume and a preset number of injections. Then, the ammonia change ratio can be determined as the ratio between the actual decrease in ammonia gas and the expected change in ammonia gas. Finally, if the ammonia change ratio is less than a preset change ratio, it can be determined that the ammonia pressure is unreliable or the ammonia metering valve is blocked.

[0088] S360. After the test injection operation is completed, confirm that the exhaust gas aftertreatment system has entered the injection state.

[0089] In this step, specifically, when the number of test injections corresponding to the ammonia metering valve is greater than or equal to the preset injection number threshold, the exhaust gas aftertreatment system is determined to enter the injection state.

[0090] In an optional embodiment of the present invention, when the target state is the injection state, the ammonia tank pressure is collected by an ammonia tank pressure sensor and the ammonia gas pressure is collected by an ammonia gas pressure sensor; when the ammonia tank pressure is greater than or equal to a first preset ammonia gas pressure and less than a third preset ammonia gas pressure, the pressure regulating shut-off valve is kept open; the actual injection volume of ammonia gas for each injection is obtained, and the first ammonia gas injection number when the actual injection volume is less than a first preset injection volume threshold is counted; the average ammonia gas pressure and the average ammonia tank pressure during each ammonia gas injection process are obtained, and the second ammonia gas injection number when the actual injection volume is less than the first preset injection volume threshold and the difference between the average ammonia gas pressure and the average ammonia tank pressure during the ammonia gas injection process is less than a preset deviation threshold is counted; if the ratio between the first ammonia gas injection number and the second ammonia gas injection number is less than a second preset ratio threshold, then both the ammonia tank pressure and the ammonia gas pressure are determined to be unreliable; when the ammonia tank pressure is greater than the third preset ammonia gas pressure within a preset time period, the third ammonia gas injection number when the actual injection volume is within the preset injection volume range is counted; the number of ammonia gas injections when the actual injection volume is within the preset injection volume range and the pressure difference in the ammonia storage tank before and after injection is less than a certain threshold is counted. The fourth ammonia injection is defined as follows: First, a first preset pressure difference, and the pressure difference within the ammonia gas rail before and after injection is greater than the second preset pressure difference. If the ratio between the third and fourth ammonia injection times is greater than or equal to the second preset ratio threshold, the ammonia tank pressure is determined to be unreliable. The fifth ammonia injection is defined as follows: The actual injection volume is within the preset injection volume range, and the pressure difference within the ammonia storage tank before and after injection is greater than the first preset pressure difference, and the pressure difference within the ammonia gas rail before and after injection is less than the second preset pressure difference. If the ratio between the third and fifth ammonia injection times is greater than or equal to the second preset pressure difference... If the ratio threshold is not met, the ammonia pressure is determined to be unreliable. The sixth ammonia injection is defined as one where the actual injection volume is within the preset injection volume range, the pressure difference in the ammonia storage tank before and after injection is greater than the first preset pressure difference, and the pressure difference in the ammonia gas rail before and after injection is greater than the second preset pressure difference. If the ratio between the third and sixth ammonia injections is greater than or equal to the third preset ratio threshold, both the ammonia tank pressure and the ammonia pressure are determined to be reliable. If the ratio between the third and sixth ammonia injections is less than the third preset ratio threshold, both the ammonia tank pressure and the ammonia pressure are determined to be unreliable.

[0091] For example, if the first preset ammonia pressure is 140 kPa and the third preset ammonia pressure is 300 kPa, then when the ammonia tank pressure is greater than or equal to 140 kPa and less than 300 kPa, the pressure regulating shut-off valve is kept open. If the first preset injection volume threshold is 10 mg, then ammonia injection operations with an actual injection volume of less than 10 mg can be statistically analyzed.

[0092] like Figure 4As shown, if the ratio between the third and fourth ammonia injection counts is greater than or equal to 95%, the ammonia tank pressure is determined to be unreliable. If the ratio between the third and sixth ammonia injection counts is greater than or equal to 90%, the ammonia tank pressure is determined to be reliable.

[0093] Figure 5 This is a flowchart of an ammonia pressure reliability diagnosis method provided according to an embodiment of the present invention.

[0094] Assuming the preset time period is 10 seconds, the third preset ammonia pressure is 300 kPa, and the preset injection volume range is greater than or equal to 150 mg and less than or equal to 350 mg, then when the ammonia tank pressure is greater than 300 kPa within 10 seconds, the number of third ammonia injections with the actual injection volume within the preset injection volume range is counted.

[0095] like Figure 5 As shown, if the ratio between the first and second ammonia injection counts is less than 95%, the ammonia pressure is deemed unreliable. The fourth ammonia injection count is calculated based on actual injection rates between 150 mg / s and 350 mg / s, with a pressure difference in the ammonia storage tank before and after injection of less than 7 kPa, and a pressure difference in the ammonia gas rail before and after injection of greater than 5 kPa. If the ratio between the third and fourth ammonia injection counts is greater than or equal to 95%, the ammonia pressure is deemed unreliable.

[0096] The fifth ammonia injection is defined as one where the actual injection rate is between 150 mg / s and 350 mg / s, the pressure difference within the ammonia storage tank before and after injection is greater than 7 kPa, and the pressure difference within the ammonia gas rail before and after injection is less than 5 kPa. If the ratio between the third and fifth ammonia injections is less than 95%, the ammonia pressure is considered reliable.

[0097] The sixth ammonia injection is defined as one where the actual injection rate is between 150 mg / s and 350 mg / s, the pressure difference within the ammonia storage tank before and after injection is greater than 7 kPa, and the pressure difference within the ammonia gas rail before and after injection is greater than 5 kPa. If the ratio between the third and sixth ammonia injections is greater than or equal to 90%, the ammonia pressure is considered reliable.

[0098] S370. Obtain the current target state of the exhaust gas aftertreatment system and at least one preset judgment condition corresponding to the target state.

[0099] S380. According to the preset judgment conditions corresponding to the target state, perform the switching control of the pressure regulating shut-off valve and the switching control of the ammonia metering valve, and collect at least one of the ammonia tank pressure and the ammonia pressure through the ammonia tank pressure sensor, and determine the reliability of the ammonia tank pressure and / or ammonia pressure collected under the target state.

[0100] S390. During the fault detection process, if it is determined, based on the reliability of the ammonia tank pressure and / or ammonia gas pressure under at least one target condition, that the unreliable diagnostic conditions for the ammonia tank pressure or ammonia gas pressure are met, then the fault detection process ends and a detection result is generated.

[0101] In one specific implementation, if the ammonia tank pressure is unreliable in the initial state and unreliable in the ammonia tank pressure during the ammonia filling state, then the unreliable diagnostic condition for ammonia tank pressure is determined to be met. If the ammonia tank pressure is unreliable during the ammonia filling diagnostic state, then the unreliable diagnostic condition for ammonia tank pressure is determined to be met. If the ammonia pressure is unreliable in both the test injection state and the injection state, then the unreliable diagnostic condition for ammonia pressure is determined to be met. Optionally, the injection volume within a preset injection volume range can be recorded as the maximum injection volume. If the ammonia tank pressure is unreliable under the maximum injection condition, then the unreliable diagnostic condition for ammonia tank pressure is determined to be met.

[0102] The technical solution of this invention sets multiple target states for the exhaust gas aftertreatment system and determines the fault status of the exhaust gas aftertreatment system layer by layer according to the preset judgment conditions corresponding to the target states, thereby avoiding false alarms and missed alarms and improving the accuracy and reliability of fault diagnosis.

[0103] Figure 6 This is a schematic diagram of a preferred exhaust gas aftertreatment system according to an embodiment of the present invention. To illustrate the fault diagnosis method and effects of the exhaust gas aftertreatment system in this solution in detail, a most detailed implementation method is described below:

[0104] like Figure 6The exhaust gas aftertreatment system 11 shown includes: an ammonia storage tank 101, an ammonia gas rail 102, a pressure regulating shut-off valve 103, an ammonia metering valve 104, a controller 105, an ammonia tank pressure sensor 106, an ammonia gas pressure sensor 107, an ammonia tank temperature sensor 201, a heat exhaust heating valve 202, an SCR carrier 203, an ammonia gas temperature sensor 204, an outlet exhaust temperature sensor 205, an outlet nitrogen and oxygen sensor 206, an inlet nitrogen and oxygen sensor 207, and an inlet exhaust temperature sensor 208. The system includes: an ammonia tank temperature sensor 201 to monitor the temperature of the ammonia storage tank 101; an exhaust heating valve 202 to control whether engine exhaust gas is input into the ammonia storage tank 101; an SCR carrier 203 to catalytically reduce nitrogen oxides in the exhaust gas; an ammonia temperature sensor 204 to monitor the temperature of the ammonia gas rail 102; an outlet exhaust temperature sensor 205 to monitor the temperature of the exhaust gas after catalytic reduction treatment, so that the controller 105 controls the opening time of the outlet nitrogen oxide sensor 206 based on the treated exhaust gas temperature; the outlet nitrogen oxide sensor 206 to monitor the nitrogen oxide concentration in the treated exhaust gas; an inlet nitrogen oxide sensor 207 to monitor the nitrogen oxide concentration in the engine exhaust gas; and an inlet exhaust temperature sensor 208 to monitor the temperature of the engine exhaust gas. Optionally, a pre-treatment system can be installed between the engine and the exhaust aftertreatment system. The pre-treatment system can be of various types, such as a diesel engine oxidation catalyst and a diesel engine particulate filter.

[0105] Figure 7 This is a flowchart of a preferred fault diagnosis method for an exhaust gas aftertreatment system according to an embodiment of the present invention. Figure 7 As shown, the system first acquires the upper and lower temperature limits measured by each temperature sensor in the exhaust gas aftertreatment system within 5 seconds of the controller being powered on. If all measured temperature values ​​are less than 30 degrees Celsius, and the difference between the upper and lower temperature limits corresponding to each sensor is within 10 degrees Celsius, the exhaust gas aftertreatment system can be controlled to enter the cold start state (i.e., if the enabling conditions are met, the exhaust gas aftertreatment system is controlled to enter the cold start state). If the entry conditions for the cold start state are not met, or if the proportion of remaining ammonia in the ammonia storage tank is greater than or equal to the preset remaining proportion, an output pressure unreliable diagnostic incomplete message will be displayed.

[0106] Determine if the ammonia tank pressure is less than 120 kPa during cold start-up. If yes, control the exhaust gas aftertreatment system to enter ammonia filling mode. If ammonia filling fails (i.e., the ammonia tank pressure is greater than or equal to the second preset ammonia pressure, but the ammonia pressure is less than the second preset ammonia pressure), control the exhaust gas aftertreatment system to enter ammonia filling diagnostic mode. In ammonia filling diagnostic mode, if the ammonia tank pressure is greater than or equal to 7 kPa, but the ammonia pressure is less than 5 kPa, the ammonia tank pressure is considered normal, but the ammonia pressure is unreliable. If the ammonia tank pressure is greater than or equal to 7 kPa and the ammonia pressure is greater than or equal to 5 kPa, both the ammonia tank pressure and the ammonia pressure are considered normal. If the ammonia tank pressure is less than 7 kPa and the ammonia pressure is less than 5 kPa, and the difference between the first average value and the second average value is greater than 10 kPa, the ammonia tank pressure is considered unreliable. If the ammonia tank pressure is less than 7 kPa, but the ammonia pressure is greater than or equal to 5 kPa, the ammonia tank pressure is considered unreliable.

[0107] If ammonia filling is successful and test injection is completed, the ammonia tank pressure and ammonia pressure are determined to be normal based on multiple preset judgment conditions corresponding to the injection state and the reliability of the ammonia tank pressure during the test injection state. If the ratio between the first and second ammonia injection times (i.e., the normal ratio of pressure difference) is less than 95%, and the ammonia tank pressure during the test injection state is unreliable, then the ammonia pressure during the injection state is determined to be unreliable. Here, "small injection quantity" refers to the case where the actual injection quantity is less than the first preset injection quantity threshold.

[0108] Under high injection rates, if the ratio between the third and fourth ammonia injection counts is greater than or equal to 95%, the ammonia tank pressure is determined to be unreliable; if the ratio between the third and fifth ammonia injection counts is greater than or equal to 95%, the ammonia pressure is determined to be unreliable; if the ratio between the third and sixth ammonia injection counts is less than 90%, both the ammonia tank pressure and the ammonia pressure are determined to be unreliable.

[0109] The advantage of this setup is that by controlling the exhaust aftertreatment system to enter the next state when it is not in the off state, and monitoring the reliability of ammonia pressure in the next state, the above process is repeated until the exhaust aftertreatment system enters the off state, thereby improving the accuracy and reliability of fault diagnosis results.

[0110] Example 3

[0111] Figure 8 This is a schematic diagram of a fault diagnosis device for an exhaust aftertreatment system according to Embodiment 3 of the present invention. This embodiment is applicable to fault diagnosis of exhaust aftertreatment systems. The fault diagnosis device for exhaust aftertreatment systems can be implemented in hardware and / or software and can be configured in a vehicle.

[0112] like Figure 8 As shown, the fault diagnosis device for the exhaust gas aftertreatment system disclosed in this embodiment is applied to the exhaust gas aftertreatment system, which includes: an ammonia storage tank, an ammonia gas rail, a pressure regulating shut-off valve, an ammonia metering valve, a controller, an ammonia tank pressure sensor, and an ammonia gas pressure sensor. The ammonia storage tank is used to store ammonia gas; the pressure regulating shut-off valve is used to control whether to input ammonia gas from the ammonia storage tank into the ammonia gas rail; the ammonia metering valve is used to inject ammonia gas into the ammonia gas rail; the ammonia tank pressure sensor is used to monitor the ammonia pressure in the ammonia storage tank; the ammonia pressure sensor is used to monitor the ammonia pressure in the ammonia gas rail; the device is executed by the controller, and the device includes:

[0113] The state transition module 81 is used to control the exhaust gas aftertreatment system to perform state transitions in multiple working states according to a preset state transition sequence when the fault diagnosis conditions are detected. The state transition sequence includes: initialization state, cold start state, ammonia filling state, ammonia filling diagnosis state, test injection state, and injection state.

[0114] The judgment condition acquisition module 82 is used to acquire the target state of the exhaust gas aftertreatment system and at least one preset judgment condition corresponding to the target state.

[0115] The confidence status determination module 83 is used to perform on / off control of the pressure regulating shut-off valve and the ammonia metering valve according to the preset judgment conditions corresponding to the target state, and to determine the confidence status of the ammonia tank pressure and / or ammonia pressure collected under the target state by collecting at least one of the ammonia tank pressure and the ammonia pressure collected by the ammonia pressure sensor.

[0116] The test result generation module 84 is used to terminate the fault detection process and generate test results if, during the fault detection process, it is determined, based on the reliability of the ammonia tank pressure and / or ammonia gas pressure under at least one target state, that the unreliable diagnostic conditions for ammonia tank pressure or ammonia gas pressure are met.

[0117] The technical solution in this embodiment, through the cooperation of the state transition module, the judgment condition acquisition module, the reliability determination module, and the detection result generation module, solves the problem that the existing technology cannot detect system faults in a timely manner, resulting in inaccurate ammonia injection volume and poor exhaust gas treatment effect. It avoids the situation of using a faulty exhaust gas after-treatment system for exhaust gas after-treatment, ensures the accuracy of ammonia injection, and improves the exhaust gas treatment effect.

[0118] Optionally, the device further includes a state transition module, which includes:

[0119] The initialization state entry unit is used to control the exhaust gas aftertreatment system to power on and determine that the exhaust gas aftertreatment system has entered the initialization state when the fault diagnosis conditions are detected.

[0120] The cold start state entry unit is used to determine that the exhaust gas aftertreatment system enters the cold start state if the temperature detection value of at least one detection point meets the preset temperature detection conditions in the initialization state.

[0121] The ammonia filling state entry unit is used to fill the ammonia storage tank with ammonia and determine that the tail gas after-treatment system has entered the ammonia filling state if the pressure of the ammonia tank is detected to meet the preset pressure threshold during cold start-up.

[0122] The ammonia filling diagnostic state entry unit is used to determine that the exhaust gas after-treatment system has entered the ammonia filling diagnostic state if the ammonia tank pressure and ammonia pressure meet the diagnostic conditions after entering the ammonia filling state.

[0123] The test injection state entry unit is used to determine that the exhaust gas after-treatment system has entered the test injection state after confirming that the ammonia filling is complete or the ammonia filling diagnosis has passed, and to execute a set number of test injection operations by controlling the opening and closing of the ammonia metering valve.

[0124] The injection status entry unit is used to determine whether the exhaust gas aftertreatment system has entered the injection status after the test injection operation is completed.

[0125] Optionally, the trusted situation determination module 83 includes:

[0126] The first pressure acquisition unit is used to acquire the pressure of the ammonia tank through the ammonia tank pressure sensor and the pressure of the ammonia gas through the ammonia gas pressure sensor when the target state is ammonia gas filling state.

[0127] The pressure change determination unit is used to obtain the target ammonia tank pressure in the ammonia storage tank after a preset duration when the ammonia tank pressure is less than the first preset ammonia pressure, and to determine the pressure change in the ammonia storage tank based on the ammonia tank pressure and the target ammonia tank pressure.

[0128] The first reliability judgment unit is used to determine the reliability of the ammonia tank pressure if the ammonia tank pressure is less than the second preset ammonia pressure and the pressure change is greater than or equal to the preset pressure difference.

[0129] The second credibility judgment unit is used to determine that the ammonia tank pressure is unreliable if the target ammonia tank pressure is greater than or equal to the second preset ammonia pressure, or if the pressure change is less than the preset pressure difference.

[0130] The second pressure acquisition unit is used to acquire the ammonia tank pressure through the ammonia tank pressure sensor and the ammonia pressure through the ammonia gas pressure sensor when the target state is the ammonia filling diagnostic state.

[0131] The valve opening unit is used to control the pressure regulating shut-off valve and the ammonia metering valve to open when the ammonia tank pressure is greater than or equal to the first preset ammonia pressure and the ammonia pressure is less than the first preset ammonia pressure.

[0132] The pressure average value acquisition unit is used to acquire the ammonia tank pressure difference at the start and end of the diagnosis time and the ammonia tank pressure average value within the diagnosis time after a preset diagnosis time, and to acquire the ammonia gas rail pressure difference at the start and end of the diagnosis time and the ammonia gas pressure average value within the diagnosis time.

[0133] The third reliability judgment unit is used to determine that the ammonia tank pressure under the ammonia filling diagnostic state is unreliable if the ammonia tank pressure difference is less than the first preset pressure difference, the ammonia gas pressure difference is less than the second preset pressure difference, and the average ammonia tank pressure and the average ammonia gas pressure are less than the third preset pressure difference.

[0134] The fourth reliability judgment unit is used to determine that the ammonia tank pressure under the ammonia filling diagnostic state is unreliable and the ammonia pressure is reliable if the pressure difference of the ammonia tank is less than the first preset pressure difference and the ammonia pressure difference is greater than or equal to the second preset pressure difference.

[0135] The fifth reliability judgment unit is used to determine that the ammonia tank pressure under the ammonia filling diagnostic state is reliable and the ammonia pressure is unreliable if the pressure difference of the ammonia tank is greater than or equal to the first preset pressure difference and the ammonia pressure difference is less than the second preset pressure difference.

[0136] The sixth reliability judgment unit is used to determine that the ammonia tank pressure and ammonia pressure under the ammonia filling diagnostic state are both reliable if the ammonia tank pressure difference is greater than or equal to the first preset pressure difference and the ammonia gas pressure difference is greater than or equal to the second preset pressure difference.

[0137] The third pressure acquisition unit is used to acquire ammonia pressure through an ammonia pressure sensor when the target state is a test injection state.

[0138] The ammonia pressure difference acquisition unit is used to control the ammonia metering valve to inject ammonia into the ammonia gas rail according to the preset single injection amount and preset injection number, and to collect the ammonia pressure again through the ammonia pressure sensor to obtain the ammonia pressure difference of the ammonia gas rail before and after ammonia injection.

[0139] The expected change determination unit is used to determine the expected change in ammonia gas based on the preset single injection quantity and the preset number of injections.

[0140] The ammonia change ratio determination unit is used to determine the actual reduction of ammonia in the ammonia gas rail based on the ammonia pressure difference, and to determine the ammonia change ratio based on the actual reduction of ammonia and the expected change of ammonia.

[0141] The seventh credibility judgment unit is used to determine that the ammonia pressure is unreliable if the ammonia change ratio is less than the first preset ratio threshold; and to determine that the ammonia pressure is reliable if the ammonia change ratio is greater than or equal to the first preset ratio threshold.

[0142] The fourth pressure acquisition unit is used to acquire the ammonia tank pressure through the ammonia tank pressure sensor and the ammonia gas pressure through the ammonia gas pressure sensor when the target state is the injection state.

[0143] The shut-off valve control unit is used to control the pressure regulating shut-off valve to remain open when the ammonia tank pressure is greater than or equal to the first preset ammonia pressure and less than the third preset ammonia pressure.

[0144] The first injection count unit is used to obtain the actual amount of ammonia injected each time and count the first number of ammonia injections when the actual amount of injection is less than the first preset injection amount threshold.

[0145] The second injection count unit is used to obtain the average ammonia pressure and the average ammonia tank pressure during each ammonia injection process, and to count the second ammonia injection count when the actual injection volume is less than the first preset injection volume threshold and the difference between the average ammonia pressure and the average ammonia tank pressure during the ammonia injection process is less than the preset deviation threshold.

[0146] The eighth reliability judgment unit is used to determine that both the ammonia tank pressure and the ammonia pressure are unreliable if the ratio between the first ammonia injection number and the second ammonia injection number is less than the second preset ratio threshold.

[0147] The third injection count unit is used to count the number of ammonia injections within the preset injection range when the ammonia tank pressure is greater than the third preset ammonia pressure within the preset time period.

[0148] The fourth injection count unit is used to count the fourth ammonia injection count when the actual injection volume is within the preset injection volume range, the pressure difference in the ammonia storage tank before and after injection is less than the first preset pressure difference, and the pressure difference in the ammonia gas rail before and after injection is greater than the second preset pressure difference.

[0149] The ninth credibility judgment unit is used to determine that the ammonia tank pressure is unreliable if the ratio between the third ammonia injection number and the fourth ammonia injection number is greater than or equal to the second preset ratio threshold.

[0150] The fifth injection count unit is used to count the fifth ammonia injection count when the actual injection volume is within the preset injection volume range, the pressure difference in the ammonia storage tank before and after injection is greater than the first preset pressure difference, and the pressure difference in the ammonia gas rail before and after injection is less than the second preset pressure difference.

[0151] The tenth credibility judgment unit is used to determine that the ammonia pressure is unreliable if the ratio between the third ammonia injection number and the fifth ammonia injection number is greater than or equal to the second preset ratio threshold.

[0152] The sixth injection count unit is used to count the sixth ammonia injection count when the actual injection volume is within the preset injection volume range, the pressure difference in the ammonia storage tank before and after injection is greater than the first preset pressure difference, and the pressure difference in the ammonia gas rail before and after injection is greater than the second preset pressure difference.

[0153] The eleventh reliability judgment unit is used to determine that both the ammonia tank pressure and the ammonia pressure are reliable if the ratio between the third ammonia injection number and the sixth ammonia injection number is greater than or equal to the third preset ratio threshold.

[0154] The twelfth reliability judgment unit is used to determine that both the ammonia tank pressure and the ammonia pressure are unreliable if the ratio between the third ammonia injection number and the sixth ammonia injection number is less than the third preset ratio threshold.

[0155] Optionally, the detection result generation module 84 includes:

[0156] The first result generation unit is used to determine that the unreliable diagnostic condition of the ammonia tank pressure is met if the ammonia tank pressure is unreliable in the initial state and the ammonia tank pressure in the ammonia filling state.

[0157] The second result generation unit is used to determine if the ammonia tank pressure is unreliable under the ammonia filling diagnostic state, and if so, that the unreliable diagnostic condition of the ammonia tank pressure is met.

[0158] The third result generation unit is used to determine whether the ammonia pressure is unreliable if both the test injection state and the injection state are unreliable.

[0159] The fault diagnosis device for the exhaust gas aftertreatment system provided in the embodiments of the present invention can execute the fault diagnosis method for the exhaust gas aftertreatment system provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the method.

[0160] Example 4

[0161] Figure 9 A schematic diagram of the structure of a vehicle 10 that can be used to implement an embodiment of the present invention is shown. For example... Figure 9As shown, vehicle 20 includes at least one controller 21 and a memory, such as read-only memory (ROM) 22 and random access memory (RAM) 23, communicatively connected to at least one controller 21. The memory stores computer programs executable by at least one controller. Controller 21 can perform various appropriate actions and processes based on the computer program stored in ROM 22 or loaded from storage unit 18 into RAM 23. RAM 23 can also store various programs and data required for the operation of vehicle 20. Controller 21, ROM 22, and RAM 23 are interconnected via bus 24. Input / output (I / O) interface 25 is also connected to bus 24.

[0162] Multiple components in vehicle 20 are connected to I / O interface 25, including: input unit 26, such as keyboard, mouse, etc.; output unit 27, such as various types of displays, speakers, etc.; storage unit 28, such as disk, optical disk, etc.; and communication unit 29, such as network card, modem, wireless transceiver, etc. Communication unit 29 allows vehicle 20 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0163] Controller 21 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of controller 21 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various controllers running machine learning model algorithms, a digital signal controller (DSP), and any suitable controller, microcontroller, etc. Controller 21 performs the various methods and processes described above, such as fault diagnosis methods for exhaust gas aftertreatment systems.

[0164] In some embodiments, the fault diagnosis method for the exhaust aftertreatment system can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 28. In some embodiments, part or all of the computer program can be loaded and / or installed on vehicle 20 via ROM 22 and / or communication unit 29. When the computer program is loaded into RAM 23 and executed by controller 21, one or more steps of the fault diagnosis method for the exhaust aftertreatment system described above can be performed. Alternatively, in other embodiments, controller 21 can be configured to perform the fault diagnosis method for the exhaust aftertreatment system by any other suitable means (e.g., by means of firmware).

[0165] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable controller, which may be a dedicated or general-purpose programmable controller, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0166] Computer programs used to implement the methods of the present invention can be written in any combination of one or more programming languages. These computer programs can be provided to a controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the controller, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The computer programs can be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0167] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0168] To provide interaction with the user, the systems and technologies described herein can be implemented in a vehicle having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the vehicle. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0169] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0170] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0171] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0172] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A fault diagnosis method for an exhaust gas aftertreatment system, characterized in that, This invention relates to an exhaust gas aftertreatment system, comprising: an ammonia storage tank, an ammonia gas rail, a pressure regulating shut-off valve, an ammonia metering valve, a controller, an ammonia tank pressure sensor, and an ammonia gas pressure sensor. The ammonia storage tank stores ammonia gas. The pressure regulating shut-off valve controls whether ammonia gas from the storage tank is introduced into the ammonia gas rail. The ammonia metering valve controls whether ammonia gas is injected into the ammonia gas rail. The ammonia tank pressure sensor monitors the ammonia pressure within the storage tank. The ammonia gas pressure sensor monitors the ammonia pressure within the ammonia gas rail. The method is executed by the controller, and the method includes: When the fault diagnosis conditions are met, the exhaust gas aftertreatment system is controlled to switch between multiple working states according to a preset state transition sequence. The state transition sequence includes: initialization state, cold start state, ammonia filling state, ammonia filling diagnosis state, test injection state, and injection state. The target state of the exhaust gas aftertreatment system and at least one preset judgment condition corresponding to the target state are obtained. According to the preset judgment conditions corresponding to the target state, the switch control of the pressure regulating shut-off valve and the switch control of the ammonia metering valve are executed. At least one of the following is collected: the ammonia tank pressure is collected by the ammonia tank pressure sensor and the ammonia pressure is collected by the ammonia gas pressure sensor. The reliability of the ammonia tank pressure and / or ammonia gas pressure collected under the target state is determined. During the fault detection process, if, based on the reliability of the ammonia tank pressure and / or ammonia gas pressure under at least one target condition, it is determined that the unreliable diagnostic conditions for the ammonia tank pressure or ammonia gas pressure are met, the fault detection process ends and the detection results are generated.

2. The method according to claim 1, characterized in that, When the fault diagnosis conditions are met, the exhaust gas aftertreatment system is controlled to transition between multiple operating states according to a preset state transition sequence, including: When the fault diagnosis conditions are detected, the exhaust gas aftertreatment system is powered on, and the exhaust gas aftertreatment system is determined to enter the initialization state. In the initialization state, if it is determined that the temperature detection value of at least one detection point meets the preset temperature detection conditions, then the exhaust gas aftertreatment system is determined to enter the cold start state. In the cold start state, if the pressure of the ammonia tank is detected to meet the preset pressure threshold, the ammonia storage tank is filled with ammonia, and the tail gas after-treatment system is determined to enter the ammonia filling state. After entering the ammonia filling state, if the ammonia tank pressure and ammonia pressure are detected to meet the diagnostic conditions, the exhaust gas aftertreatment system is determined to have entered the ammonia filling diagnostic state. After confirming that ammonia filling is complete or that ammonia filling diagnosis is passed, the exhaust gas aftertreatment system is put into trial injection mode, and the set number of trial injection operations are performed by controlling the opening and closing of the ammonia metering valve. After the test injection operation is completed, confirm that the exhaust gas aftertreatment system has entered the injection state.

3. The method according to claim 1, characterized in that, Based on preset judgment conditions corresponding to the target state, the system executes on / off control of the pressure regulating shut-off valve and the ammonia metering valve. It also collects at least one of the following: ammonia tank pressure via an ammonia tank pressure sensor and ammonia pressure via an ammonia gas pressure sensor. The system determines the reliability of the collected ammonia tank pressure and / or ammonia gas pressure under the target state, including: When the target state is ammonia filling state, the ammonia tank pressure is collected by the ammonia tank pressure sensor, and the ammonia pressure is collected by the ammonia gas pressure sensor. When the pressure in the ammonia tank is less than the first preset ammonia pressure, the target ammonia tank pressure in the ammonia storage tank is obtained after a preset duration, and the pressure change in the ammonia storage tank is determined based on the ammonia tank pressure and the target ammonia tank pressure. If the pressure in the ammonia tank is less than the second preset ammonia pressure, and the pressure change is greater than or equal to the preset pressure difference, then the pressure in the ammonia tank is determined to be reliable. If the target ammonia tank pressure is greater than or equal to the second preset ammonia pressure, or if the pressure change is less than the preset pressure difference, then the ammonia tank pressure is determined to be unreliable.

4. The method according to claim 1, characterized in that, Based on preset judgment conditions corresponding to the target state, the system executes on / off control of the pressure regulating shut-off valve and the ammonia metering valve. It also collects at least one of the following: ammonia tank pressure via an ammonia tank pressure sensor and ammonia pressure via an ammonia gas pressure sensor. The system determines the reliability of the collected ammonia tank pressure and / or ammonia gas pressure under the target state, including: When the target state is the ammonia filling diagnostic state, the ammonia tank pressure is collected by the ammonia tank pressure sensor, and the ammonia pressure is collected by the ammonia gas pressure sensor. When the pressure in the ammonia tank is greater than or equal to the first preset ammonia pressure, and the ammonia pressure is less than the first preset ammonia pressure, the pressure regulating shut-off valve and the ammonia metering valve are controlled to open. After a preset diagnostic time, the ammonia tank pressure difference at the start and end of the diagnostic time, and the average ammonia tank pressure during the diagnostic time are obtained. The ammonia gas rail pressure difference at the start and end of the diagnostic time, and the average ammonia gas pressure during the diagnostic time are also obtained. If the pressure difference of the ammonia tank is less than the first preset pressure difference, the pressure difference of ammonia gas is less than the second preset pressure difference, and the average pressure of the ammonia tank and the average pressure of ammonia gas are less than the third preset pressure difference, then the pressure of the ammonia tank under the ammonia filling diagnostic state is determined to be unreliable. If the pressure difference of the ammonia tank is less than the first preset pressure difference, and the pressure difference of the ammonia gas is greater than or equal to the second preset pressure difference, then the pressure of the ammonia tank under the ammonia filling diagnostic state is determined to be unreliable, and the pressure of the ammonia gas is reliable. If the pressure difference of the ammonia tank is greater than or equal to the first preset pressure difference, and the pressure difference of the ammonia gas is less than the second preset pressure difference, then the ammonia tank pressure under the ammonia filling diagnostic state is determined to be reliable, and the ammonia gas pressure is not reliable. If the pressure difference of the ammonia tank is greater than or equal to the first preset pressure difference, and the pressure difference of the ammonia gas is greater than or equal to the second preset pressure difference, then the pressure of the ammonia tank and the pressure of the ammonia gas under the ammonia filling diagnostic state are both reliable.

5. The method according to claim 1, characterized in that, Based on preset judgment conditions corresponding to the target state, the system executes on / off control of the pressure regulating shut-off valve and the ammonia metering valve. It also collects at least one of the following: ammonia tank pressure via an ammonia tank pressure sensor and ammonia pressure via an ammonia gas pressure sensor. The system determines the reliability of the collected ammonia tank pressure and / or ammonia gas pressure under the target state, including: When the target state is the test injection state, the ammonia pressure is collected by the ammonia pressure sensor; The ammonia metering valve is controlled to inject ammonia into the ammonia gas rail according to a preset single injection volume and a preset number of injections, and the ammonia pressure is collected again by the ammonia pressure sensor to obtain the ammonia pressure difference of the ammonia gas rail before and after ammonia injection. The expected change in ammonia gas is determined based on the preset single injection volume and the preset number of injections. Based on the ammonia pressure difference, determine the actual reduction of ammonia in the ammonia gas rail, and based on the actual reduction of ammonia and the expected change in ammonia, determine the ammonia change ratio. If the ammonia change ratio is less than the first preset ratio threshold, then the ammonia pressure is determined to be unreliable. If the ammonia change ratio is greater than or equal to the first preset ratio threshold, then the ammonia pressure is determined to be reliable.

6. The method according to claim 1, characterized in that, Based on preset judgment conditions corresponding to the target state, the system executes on / off control of the pressure regulating shut-off valve and the ammonia metering valve. It also collects at least one of the following: ammonia tank pressure via an ammonia tank pressure sensor and ammonia pressure via an ammonia gas pressure sensor. The system determines the reliability of the collected ammonia tank pressure and / or ammonia gas pressure under the target state, including: When the target state is the injection state, the ammonia tank pressure is collected by the ammonia tank pressure sensor and the ammonia gas pressure is collected by the ammonia gas pressure sensor. When the pressure in the ammonia tank is greater than or equal to the first preset ammonia pressure and less than the third preset ammonia pressure, the pressure regulating shut-off valve is kept open. Obtain the actual amount of ammonia injected each time, and count the number of ammonia injections where the actual amount injected is less than the first preset injection amount threshold. The average ammonia pressure and the average ammonia tank pressure during each ammonia injection process are obtained, and the number of ammonia injections that are less than the first preset injection volume threshold and the difference between the average ammonia pressure and the average ammonia tank pressure during the ammonia injection process is less than the preset deviation threshold is counted. If the ratio between the first and second ammonia injection counts is less than the second preset ratio threshold, then both the ammonia tank pressure and the ammonia pressure are determined to be unreliable. When the pressure of the ammonia tank is greater than the third preset ammonia pressure within the preset time period, the number of times the actual injection volume is within the preset injection volume range is counted. The fourth ammonia injection is defined as follows: the actual injection volume is within the preset injection volume range, the pressure difference in the ammonia storage tank before and after injection is less than the first preset pressure difference, and the pressure difference in the ammonia gas rail before and after injection is greater than the second preset pressure difference. If the ratio between the third and fourth ammonia injection counts is greater than or equal to the second preset ratio threshold, the ammonia tank pressure is determined to be unreliable. The fifth ammonia injection is defined as follows: the actual injection volume is within the preset injection volume range, the pressure difference in the ammonia storage tank before and after injection is greater than the first preset pressure difference, and the pressure difference in the ammonia gas rail before and after injection is less than the second preset pressure difference. If the ratio between the third and fifth ammonia injection counts is greater than or equal to the second preset ratio threshold, then the ammonia pressure is determined to be unreliable. The sixth ammonia injection is defined as follows: the actual injection volume is within the preset injection volume range, the pressure difference in the ammonia storage tank before and after injection is greater than the first preset pressure difference, and the pressure difference in the ammonia gas rail before and after injection is greater than the second preset pressure difference. If the ratio between the third and sixth ammonia injection counts is greater than or equal to the third preset ratio threshold, then both the ammonia tank pressure and the ammonia pressure are considered reliable. If the ratio between the third and sixth ammonia injection counts is less than the third preset ratio threshold, then both the ammonia tank pressure and the ammonia pressure are deemed unreliable.

7. The method according to claim 1, characterized in that, During the fault detection process, if, based on the reliability of the ammonia tank pressure and / or ammonia gas pressure under at least one target condition, it is determined that the unreliable diagnostic conditions for ammonia tank pressure or ammonia gas pressure are met, the fault detection process ends and detection results are generated, including: If the ammonia tank pressure is unreliable in the initial state and unreliable in the ammonia filling state, then the diagnostic condition for unreliable ammonia tank pressure is determined to be met. If the ammonia tank pressure under the ammonia filling diagnostic condition is unreliable, then the diagnostic condition of unreliable ammonia tank pressure is determined to be met. If the ammonia pressure under both the test injection state and the injection state is unreliable, then the diagnostic condition of unreliable ammonia pressure is met.

8. A fault diagnosis device for an exhaust gas aftertreatment system, characterized in that, This invention relates to an exhaust gas aftertreatment system, comprising: an ammonia storage tank, an ammonia gas rail, a pressure regulating shut-off valve, an ammonia metering valve, a controller, an ammonia tank pressure sensor, and an ammonia gas pressure sensor. The ammonia storage tank stores ammonia gas. The pressure regulating shut-off valve controls whether ammonia gas from the storage tank is introduced into the ammonia gas rail. The ammonia metering valve injects ammonia gas into the ammonia gas rail. The ammonia tank pressure sensor monitors the ammonia pressure within the storage tank. The ammonia gas pressure sensor monitors the ammonia pressure within the ammonia gas rail. The device is executed by the controller, and the device includes: The state transition module is used to control the exhaust gas aftertreatment system to transition through multiple working states according to a preset state transition sequence when the fault diagnosis conditions are detected. The state transition sequence includes: initialization state, cold start state, ammonia filling state, ammonia filling diagnosis state, test injection state, and injection state. The judgment condition acquisition module is used to acquire the target state of the exhaust gas aftertreatment system and at least one preset judgment condition corresponding to the target state. The confidence status determination module is used to perform on / off control of the pressure regulating shut-off valve and the ammonia metering valve according to the preset judgment conditions corresponding to the target state, and to determine the confidence status of the ammonia tank pressure and / or ammonia pressure collected under the target state by collecting at least one of the ammonia tank pressure sensor and the ammonia pressure sensor. The test result generation module is used to terminate the fault detection process and generate test results if, during the fault detection process, it is determined, based on the reliability of the ammonia tank pressure and / or ammonia gas pressure under at least one target state, that the unreliable diagnostic conditions for ammonia tank pressure or ammonia gas pressure are met.

9. A vehicle, characterized in that, The vehicles include: The exhaust gas aftertreatment system as described in any one of claims 1-7; and At least one memory, the exhaust aftertreatment system includes a controller, and the memory is communicatively connected to the controller; wherein... The memory stores a computer program that can be executed by the at least one controller, the computer program being executed by the at least one controller to enable the at least one controller to perform the fault diagnosis method for the exhaust gas aftertreatment system according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a controller configured in any one of the exhaust gas aftertreatment systems as described in claims 1-7, implement the fault diagnosis method for the exhaust gas aftertreatment system as described in any one of claims 1-7.

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