CN115614135A

CN115614135A - Verification module, controller, detector and method for exhaust gas aftertreatment system

Info

Publication number: CN115614135A
Application number: CN202110782995.1A
Authority: CN
Inventors: 刘毅
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2021-07-12
Filing date: 2021-07-12
Publication date: 2023-01-17

Abstract

The application provides a verification module for an exhaust gas aftertreatment system, which is configured to sequentially perform a pressure build-up step, a pressurization step, an injection step, and a verification step in each verification cycle through a control pressure sensor, a supply unit, and a nozzle of the exhaust gas aftertreatment system to verify whether the injection capability of the nozzle deviates from a designed injection capability. The application also provides a controller and a detector comprising the verification module, and a method for verifying the exhaust gas aftertreatment system. According to the method and the device, whether the jetting capability of the nozzle of the tail gas aftertreatment system deviates from the expected jetting capability or not can be accurately and effectively verified, so that the reliable operation of the tail gas aftertreatment system is ensured.

Description

Verification module, controller, detector and method for exhaust gas aftertreatment system

Technical Field

The present application relates generally to the field of engine exhaust treatment, and more particularly to a validation module for an exhaust aftertreatment system and a method for validating an exhaust aftertreatment system. The application also relates to a controller and a detector for an exhaust aftertreatment system.

Background

When operating, engines produce exhaust gases with a high content of nitrogen oxides, which cannot be discharged directly into the atmosphere, but which need to be treated by an exhaust gas aftertreatment system before being discharged into the atmosphere. For diesel vehicles, one effective technique for treating the exhaust gas emitted from diesel engines is to reduce the content of nitrogen oxides in the exhaust gas emitted from the engines by using a Selective Catalytic Reduction (SCR) method. The SCR method treats exhaust gas discharged from a diesel engine by using an exhaust gas treatment liquid (usually an aqueous urea solution) in an exhaust gas after-treatment system, so that harmful nitrogen oxides in the exhaust gas are converted into harmless nitrogen and water vapor, thereby reducing harmful gas emission of the diesel engine.

The exhaust gas aftertreatment system generally includes a nozzle for spraying an exhaust gas treatment liquid into an exhaust pipe of the vehicle, a supply unit arranged between a tank for storing the exhaust gas treatment liquid and the nozzle of the vehicle for supplying the exhaust gas treatment liquid to the nozzle, and a supply line connected between the supply unit and the nozzle. The jettability of a nozzle is an important parameter characterizing the performance of the nozzle, which is defined as the ability of the nozzle to allow the exhaust treatment fluid to pass therethrough. Factors such as engine emissions, exhaust aftertreatment system layout, mixer configuration, exhaust gas flow in the exhaust pipe, etc., need to be considered in selecting a nozzle with appropriate injection capabilities for an exhaust gas treatment system. Further, the jettability of a nozzle is affected by the number of nozzle orifices (the orifice diameters of the orifices are generally uniform), the presence of leaks or partial blockages in the nozzle.

In order to ensure reliable operation of the exhaust aftertreatment system, the deviation of the injection capacity of the nozzle from the design injection capacity should be detected in time. However, conventional exhaust gas aftertreatment systems are designed to control the supply unit during operation of the exhaust gas aftertreatment system by feedback regulation to stabilize the system pressure in the supply line at a predetermined value (e.g. 9 bar). If the spray capability of the nozzle is too low compared to the design spray capability (e.g., the number of spray holes of a newly installed nozzle is lower than the design number of spray holes, or the nozzle is partially clogged after operating for a certain period of time or after spraying for a certain number of times), the exhaust gas treating fluid sprayed into the exhaust pipe from the nozzle may be insufficient, and thus harmful nitrogen oxides in the exhaust gas may not be sufficiently removed. If the spray capacity of the nozzle is too high compared with the designed spray capacity (for example, the number of spray holes of the newly installed nozzle is higher than the designed number of spray holes, or the nozzle leaks after working for a period of time or spraying for a certain number of times), the tail gas treatment liquid sprayed into the tail gas pipe by the nozzle is too much. Excessive exhaust treatment fluid may crystallize and clog in, for example, mixers and Diesel Particulate Filters (DPFs), resulting in reduced performance or even failure of the exhaust treatment system.

Accordingly, there is a need for improvements to conventional exhaust aftertreatment systems.

Disclosure of Invention

The present application is directed to a verification module for an exhaust aftertreatment system to verify whether a jetting capability of a nozzle of the exhaust aftertreatment system deviates from an expected jetting capability.

According to an aspect of the application, there is provided a validation module for an exhaust gas after-treatment system comprising a nozzle configured to inject an exhaust gas treatment liquid into an exhaust pipe of a vehicle, a supply unit configured to be arranged between a tank for storing an exhaust gas treatment liquid of a vehicle and the nozzle and configured to supply the exhaust gas treatment liquid to the nozzle, a supply line connected between the supply unit and the nozzle, and a pressure sensor configured to sense a system pressure in the supply line, the validation module being configured to perform the following steps in each validation cycle in turn by controlling the pressure sensor, the supply unit and the nozzle: a pressure building step of closing the nozzle and controlling the supply unit to supply the exhaust treatment liquid from the storage tank to the supply line to build a first system pressure in the supply line; a pressurization step of keeping the nozzle closed and controlling the supply unit to continuously supply the first amount of the exhaust gas treatment liquid from the storage tank to the supply pipeline; an injection step of closing the supply unit and controlling the nozzle to be opened for a theoretical time for the nozzle to inject the first amount of the exhaust gas treatment liquid to return the system pressure in the supply line to the first system pressure; a verification step of keeping the supply unit closed and closing the nozzle, and comparing a second system pressure in the supply line with the first system pressure to verify whether the injectability of the nozzle deviates from a design injectability.

According to another aspect of the application, a controller for an exhaust gas aftertreatment system is provided, wherein the aforementioned validation module is integrated into the controller.

According to a further aspect of the application, a detector for an exhaust gas aftertreatment system is provided, wherein the aforementioned validation module is integrated into the detector.

According to yet another aspect of the application, a method for validating an exhaust gas aftertreatment system is provided, the exhaust gas aftertreatment system comprising a nozzle configured to inject an exhaust gas treatment liquid into an exhaust pipe of a vehicle, a supply unit configured to be arranged between a tank for storing the exhaust gas treatment liquid of the vehicle and the nozzle and configured to supply the exhaust gas treatment liquid to the nozzle, a supply line connected between the supply unit and the nozzle, and a pressure sensor configured to sense a system pressure in the supply line, the method comprising performing the following steps in each validation cycle in turn by controlling the pressure sensor, the supply unit and the nozzle: a pressure building step of closing the nozzle and controlling the supply unit to supply the tail gas treatment liquid from the storage tank to the supply pipeline so as to build a first system pressure in the supply pipeline; a pressurization step of keeping the nozzle closed and controlling the supply unit to continuously supply the first amount of the tail gas treatment liquid from the storage tank to the supply pipeline; an injection step of closing the supply unit and controlling the nozzle to be opened for a theoretical time for the nozzle to inject the first amount of the exhaust gas treatment liquid to return the system pressure in the supply line to the first system pressure; a verification step of keeping the supply unit closed and closing the nozzle, and comparing a second system pressure in the supply line with the first system pressure to verify whether the ejection capability of the nozzle deviates from a design ejection capability.

According to the method and the device, whether the jetting capacity of the nozzle of the exhaust gas aftertreatment system deviates from the expected jetting capacity or not can be accurately and effectively verified, and therefore reliable operation of the exhaust gas aftertreatment system is guaranteed.

Drawings

The above-described and other aspects of the present application will be more fully understood and appreciated in view of the following drawings. It should be noted that the figures are merely schematic and are not drawn to scale. In the drawings:

FIG. 1 schematically illustrates an exemplary exhaust aftertreatment system with a verification module according to a preferred embodiment of the present application integrated into a controller of the exhaust aftertreatment system; and

fig. 2 schematically illustrates a system pressure variation in the supply line of the exhaust gas aftertreatment system shown in fig. 1 during a verification cycle performed by the verification module shown in fig. 1.

List of reference numerals

1. Tail gas pipe

2. Storage tank

100. Tail gas aftertreatment system

103. Nozzle with a nozzle body

105. Supply unit

107. Drainage pipeline

109. Supply line

111. Controller for controlling a motor

113. Pressure sensor

115. Verification module

117. Liquid level sensor

Detailed Description

Some preferred embodiments of the present application are described in detail below with reference to examples. It should be understood by those skilled in the art that these embodiments are merely illustrative and are not meant to limit the present application in any way. Furthermore, the features in the embodiments of the present application may be combined with each other without conflict. In the drawings, other components have been omitted for the sake of brevity, but this does not indicate that the exhaust aftertreatment system of the present application may not include other components. It should be understood that the dimensions, proportions and numbers of elements in the drawings are not intended to limit the present application.

Fig. 1 schematically shows an exemplary exhaust gas aftertreatment system 100 for a vehicle, in particular a diesel vehicle, to be associated with an exhaust pipe (schematically indicated at 1 in fig. 1) of an engine for injecting an exhaust gas treatment fluid (typically an aqueous urea solution) into the exhaust pipe 1 to reduce the content of nitrogen oxides in the exhaust gas. The vehicle comprises a tank 2 configured to store an exhaust treatment fluid. The storage tank 2 is schematically represented in fig. 1 and may be any suitable off-gas treating liquid storage tank known in the art. The exhaust gas aftertreatment system 100 comprises a nozzle 103 configured to inject an exhaust gas treatment liquid into the exhaust pipe 1, a supply unit 105 arranged between the tank 2 and the nozzle 103 and configured to supply the exhaust gas treatment liquid to the nozzle 103. A drain line 107 is connected between the tank 2 and the supply unit 105 to enable the supply unit 105 to draw off the off-gas treatment liquid from the tank 2. The supply line 109 is connected between the supply unit 105 and the nozzle 103 to deliver the exhaust gas treatment liquid to the nozzle 103. The supply unit 105 may be any suitable device capable of quantitatively delivering the exhaust treatment liquid, such as a positive displacement pump (such as a plunger pump or the like) or a vane pump. The supply unit 105 is capable of providing a suction force during operation to extract the off-gas treatment liquid from the tank 2 and to bring the extracted off-gas treatment liquid to the nozzle 103 via the supply line 109. The nozzle 103 is typically in the form of a solenoid valve, the opening of which is typically fixed. The tail gas treatment liquid is opened and closed by electrifying and powering off the electromagnetic valve. When the electromagnetic valve is powered on, the electromagnetic force generated by the coil inside the electromagnetic valve is greater than the spring force, the armature is lifted, the injection channel is opened, and the exhaust gas treatment liquid is injected into the exhaust pipe 1 under the action of the pressure difference between the supply pipeline 109 and the exhaust pipe 1. After the electrification is finished, the armature resets under the action of the spring force, the spraying channel is closed, and the nozzle 103 stops spraying the tail gas treatment liquid.

The exhaust gas aftertreatment system 100 further comprises a controller 111 (also referred to as "injection controller (DCU)") configured to determine an injection amount of the exhaust gas treatment liquid required to be injected into the exhaust pipe 1 in response to the exhaust gas aftertreatment request, to control the supply unit 105 (as schematically indicated by the two-dot chain line in fig. 1) to supply the exhaust gas treatment liquid from the tank 2 to the nozzle 103, and to control the nozzle 103 (as also schematically indicated by the two-dot chain line in fig. 1) to quantitatively inject the exhaust gas treatment liquid into the exhaust pipe 1. Specifically, during operation of the engine of the vehicle, an Electronic Controller (ECU) of the vehicle sends an exhaust aftertreatment request to the controller 111 of the exhaust aftertreatment system 100. In response to the exhaust aftertreatment request, the controller 111 receives information regarding the engine operating state, which may include the engine speed, etc. The rotational speed of the engine is sensed, for example, by a rotational speed sensor (not shown) at the engine to indicate the operating state of the engine. The controller 111 receives data from the rotation speed sensor directly or indirectly (via the ECU) and calculates the injection amount of the exhaust treatment liquid required to be injected into the exhaust pipe 1 from the sensed data. The controller 111 controls the supply unit 105 to operate to provide a suction force to draw the exhaust treatment liquid from the storage tank 2 through the drain line 107, thereby performing pressure buildup in the supply line 109.

The exhaust aftertreatment system 100 further includes a pressure sensor 113 configured to sense a system pressure in the supply line 109. As shown in fig. 1, a pressure sensor 113 is provided at the supply line 109 to sense the system pressure in the supply line 109. It is to be understood that the pressure sensor may also be provided at the outlet of the supply unit 105 (i.e., the connection point of the supply unit 105 and the supply pipe 109) or the inlet of the nozzle 103 (i.e., the connection point of the nozzle 103 and the supply pipe 109). It should also be understood that more than one pressure sensor may be provided.

The controller 111 is also configured to control the pressure sensor 113 to sense the system pressure in the supply line 109, and to receive the sensed system pressure from the pressure sensor 113. The controller 111 is capable of adjusting the power of the supply unit 105 based on the system pressure in the supply line 109 sensed by the pressure sensor 113 so that the exhaust treatment fluid pressure in the supply line 109 tends to stabilize at a predetermined value (e.g., 9 bar). By this feedback regulation, the exhaust gas treatment liquid can be continuously supplied to the nozzle 103 via the supply line 109 during the injection. However, such feedback adjustments make it difficult to determine whether the injection capacity of the nozzle 103 deviates from the design injection capacity based on system pressure fluctuations in the supply line 109 during operation of the exhaust aftertreatment system 100. In this case, if the injection capability of the nozzle 103 is too low compared to the design injection capability, the exhaust gas treatment liquid injected into the exhaust pipe 1 by the nozzle 103 is insufficient, and harmful nitrogen oxides in the exhaust gas cannot be sufficiently removed. If the spraying capacity of the nozzle 103 is too high compared to the designed spraying capacity, the exhaust gas treating liquid sprayed into the exhaust pipe 1 by the nozzle 103 becomes excessive. Excessive exhaust treatment fluid may crystallize and cause plugging in, for example, mixers (not shown) and DPFs (not shown), resulting in reduced performance or even failure of the exhaust treatment system 100.

In order to ensure that the exhaust aftertreatment system 100 can function reliably, the validation module 115 according to a preferred embodiment of the present application is integrated in the controller 111 of the exhaust aftertreatment system 100. The verification module 115 is configured to perform a verification cycle by controlling the pressure sensor 113, the supply unit 105 and the nozzle 103 to verify whether the injection capability of the nozzle 103 of the exhaust aftertreatment system 100 deviates from a designed injection capability.

As described above, the "jettability" of a nozzle refers to the ability of the nozzle to allow the exhaust treatment fluid to pass therethrough. As used herein, the "design jettability" of a nozzle refers to the rated jettability of a suitable nozzle selected for use in designing an exhaust aftertreatment system, taking into account factors such as engine emissions, exhaust aftertreatment system layout, mixer configuration, exhaust gas flow in the exhaust pipe, and the like.

Fig. 2 schematically illustrates the system pressure variation in the supply line 109 of the exhaust aftertreatment system 100 during the execution of the validation cycle by the validation module 115. In fig. 2, the horizontal axis represents the time in seconds during which the exhaust gas aftertreatment system is operated, and the vertical axis represents the system pressure in bar in the supply line 109 of the exhaust gas aftertreatment system 100. The verification module 115 is configured to sequentially perform a pressure build-up step, a pressure increase step, an injection step, and a verification step in each verification cycle by controlling the pressure sensor 113, the supply unit 105, and the nozzle 103. These steps are described in detail below in conjunction with fig. 2.

In the step of pressure build-up (T) ₁ To T ₃ ) In the method, the nozzle 103 is closed and the supply unit 105 is controlled to supply the exhaust gas treatment liquid from the tank 2 to the supply line 109 to establish a first system pressure P in the supply line 109 ₁ . First system pressure P ₁ May be any suitable pressure greater than the tailpipe pressure in the tailpipe 1 (substantially equal to atmospheric pressure), preferably the rated operating pressure of the nozzle 103 (e.g., 9 bar). In other embodiments, the first system pressure P ₁ It may be not pre-selected but the system pressure in the supply line 109 after controlling the supply unit 105 to supply the exhaust treatment liquid from the tank 2 to the supply line 109 for pressure build-up may be recorded as the first system pressure P ₁ 。

Next, in the pressurizing step (T) ₃ To T ₄ ) While keeping the nozzle 103 closed, the supply unit 105 is controlled to continue supplying the first amount of the exhaust gas treatment liquid from the tank 2 to the supply line 109. As previously mentioned, the supply unit 105 may be any suitable device capable of quantitatively delivering the off-gas treatment liquid. Therefore, the verification module 115 can control the supply unit 105 to quantitatively supply the exhaust gas treatment liquid from the tank 2 to the supply line 109. For example, in the case of the supply unit 105 in the form of a plunger pump, the verification module 115 can control the rotational movement of the camshaft of the plunger pump to control the tappet assembly and the plunger to reciprocate, thereby controlling the plunger pump to quantitatively supply the exhaust gas treatment liquid from the tank 2 to the supply line 109. As another example, in the case that the supply unit 105 is in the form of a vane pump, the verification module 115 can control rotation of a rotating shaft of the vane pump to control the vane pump to quantitatively supply the exhaust gas treatment liquid from the storage tank 2 to the supply line 109. The term "first amount of off-gas treatment liquid" may refer to an amount of off-gas treatment liquid measured by volume or mass. In the pressure increasing step, a first amount of the exhaust gas treatment liquid is supplied to the supply line 109 such that the system pressure in the supply line 109 is from a first system pressure P ₁ To a third system pressure P ₃ 。

Next, in the injection step (T) ₄ To T ₆ ) In the method, the supply unit 105 is closed, and the nozzle 103 is controlled to be opened to continuously spray the first amount of the exhaust gas treatment liquid from the nozzle 103 to return the system pressure in the supply line 109 to the first system pressure P ₁ Theoretical time of (shown as T in FIG. 2) ₅ To T ₆ ). As used herein, "theoretical time" refers to the time calibrated in the laboratory for jetting under the same conditions for an ideal nozzle (a nozzle whose jetting capacity meets the design jetting capacity). Therefore, the theoretical time in the above-described ejection step is such that the nozzle 103 is positioned from the first position in the case where the ejection capability of the nozzle 103 conforms to the design ejection capabilityThree system pressure P ₃ The opening is initiated to inject the first quantity of exhaust treatment fluid for an elapsed time. That is, in the case where the ejection capability of the nozzle 103 conforms to the design ejection capability, the nozzle 103 is never at the third system pressure P ₃ Starting to open for this theoretical time, a first quantity of exhaust treatment liquid can be injected into the exhaust pipe 1, so that the system pressure in the supply line 109 is brought from the third system pressure P ₃ Falls back to the first system pressure P ₁ 。

Next, in a verification step (T) ₆ To T ₇ ) Keeping the supply unit closed 105 and closing the nozzle 103, and the second system pressure P in the supply line 109 ₂ With a first system pressure P ₁ A comparison is made to verify whether the jetting ability of the nozzle 103 deviates from the design jetting ability. In this verification step, the verification module 115 controls the pressure sensor 113 to measure the system pressure in the supply line 109, i.e. the system pressure in the supply line 109 after the injection step. Subsequently, the verification module 115 records the system pressure as a second system pressure P ₂ And connecting it with the first system pressure P ₁ A comparison is made to verify whether the ejection capability of the nozzle 103 deviates from the design ejection capability.

If the ejection capability of the nozzle 103 conforms to the design ejection capability, the ejection amount of the nozzle 103 in the ejection step approaches the first amount so that the second system pressure P ₂ With a first system pressure P ₁ The difference should be within a predetermined range. In other words, if the second system pressure P ₂ To the first system pressure P ₁ If the difference is within the predetermined range, it can be determined that the ejection capability of the nozzle 103 meets the design ejection capability, that is, it can be determined that the ejection capability of the nozzle 103 does not deviate from the design ejection capability. For example, if the second system pressure P ₂ To the first system pressure P ₁ Should the difference be within the range of 0.5bar, ± 0.3bar, ± 0.1bar or ± 0.05bar, or within other suitable ranges, then it may be determined that the injectability of nozzle 103 is compatible with the design injectability. As another example, if the second system pressure P ₂ With a first system pressure P ₁ The difference is between +0.5bar and-0.3 bar and between +0.3bar and-0.1 bar, +0.3bar to-0.5 bar, or in other suitable ranges, the spray capability of nozzle 103 may be determined to correspond to the design spray capability.

If the jetting ability of the nozzle 103 deviates from the design jetting ability, the jetting amount of the nozzle 103 in the jetting step may deviate from the first amount, resulting in the second system pressure P ₂ Higher than the first system pressure P ₁ Exceeding a first predetermined threshold Δ P _H Or to a second system pressure P ₂ Below the first system pressure P ₁ Exceeding a second predetermined threshold Δ P _L . In other words, if the jetting capacity of the nozzle 103 is too low compared to the design jetting capacity, the jetting amount of the nozzle 103 in the jetting step is much less than the first amount, resulting in the second system pressure P ₂ Higher than the first system pressure P ₁ Exceeding a first predetermined threshold Δ P _H . If the jetting capacity of the nozzle 103 is too high compared to the design jetting capacity, the jetting amount of the nozzle 103 in the jetting step is much more than the first amount, resulting in the second system pressure P ₂ Lower than the first system pressure P ₁ Exceeding a first predetermined threshold Δ P _L 。

That is, if the second system pressure P ₂ Higher than the first system pressure P ₁ Exceeding a first predetermined threshold Δ P _H (e.g., 0.5bar or more or less), it may be determined that the jetting ability of nozzle 103 is too low compared to the design jetting ability. This may be due to a decrease in the ejection capability of the nozzle 103 caused by the use of a nozzle having a number of orifices lower than the design orifice number when the nozzle 103 is first installed or when the nozzle 103 is replaced, or the use of a nozzle having a number of orifices corresponding to the design orifice number, but the nozzle may be partially clogged after the nozzle has been operated for a certain period of time or ejected a certain number of times. If the second system pressure P ₂ Below the first system pressure P ₁ Exceeding a second predetermined threshold Δ P _L (e.g., 0.5bar or more or less), it may be determined that the jetting ability of nozzle 103 is too high compared to the design jetting ability. This may be because a nozzle having a number of orifices exceeding the design orifice number is used when the nozzle 103 is first installed or the nozzle 103 is replaced, or although a nozzle having a number of orifices conforming to the design is usedThe number of holes, but there is a leakage (i.e. there is a leakage between the supply line 109 and the exhaust pipe 1) after the nozzle has been in operation for a certain time or a certain number of injections, resulting in a too high injection capacity of the nozzle 103 compared to the design injection capacity. It will be appreciated that the first predetermined threshold Δ P _H And a second predetermined threshold value Δ P _L May be the same or different.

In this way, the verification module 115 is able to verify whether the jetting capabilities of the nozzles 103 deviate from the designed jetting capabilities. The verification module 115 may be configured to perform at least one of the verification cycles described above in one verification to ensure the accuracy of the verification result. In some examples, the verification module 115 may exit the verification directly if the results after the verification module 115 performs one verification cycle indicate that the jetting capabilities of the nozzles 103 conform to the design jetting capabilities. If the results after the verification module 115 performs one verification cycle indicate that the jetting capabilities of the nozzles 103 deviate from the design jetting capabilities, the verification module 115 may repeat the above-described build-boost-jet-verification steps at least once to further verify the results. This makes it possible to improve the accuracy of the verification. In other words, after the verification module 115 performs at least one of the above-described verification cycles, the second system pressure P is maintained during each verification cycle ₂ With a first system pressure P ₁ When the difference is within the predetermined range, it is determined that the injectability of the nozzle 103 conforms to the design injectability, and the second system pressure P is maintained during each verification cycle ₂ Above the first system pressure P ₁ Exceeding a first predetermined threshold Δ P _H When it is determined that the injectability of the nozzle 103 is too low compared to the design injectability, the second system pressure P is determined during each verification cycle ₂ Lower than the first system pressure P ₁ Exceeding a second predetermined threshold Δ P _L It is determined that the ejection capability of the nozzle 103 is excessively high compared to the design ejection capability.

It should be understood that the ratio of the time lengths of the various steps to each other is not limited by the ratio shown in fig. 2, and the time lengths of the various steps in fig. 2 are merely exemplary. E.g. T ₂ To T ₃ 、T ₄ To T ₅ And/or T ₆ To T ₇ Can be very muchShort.

The verification module 115 can feed back the verification result to, for example, the controller 111. For example, when it is determined that the jetting ability of the nozzle 103 deviates from the design jetting ability, the controller 111 may issue an alarm to prompt a driver or other personnel on site to inspect the nozzle 103 for inspection or maintenance. In this manner, reliable operation of the exhaust aftertreatment system 100 can be ensured.

Alternatively, in other embodiments, such as T in FIG. 2 ₀ To T ₁ As shown, the validation module 115 is further configured to control the supply unit 105 to supply the off-gas treatment liquid from the tank 2 to the supply line 109 and to control the nozzle 103 to spray the off-gas treatment liquid to exhaust the gas in the supply line 109 before performing the validation cycle. This may be performed in case the nozzle 103 is first installed or replaced, or in case there is gas in the supply line 109 just when the vehicle is started. In this way, the influence of the gas in the supply line 109 on the verification result can be excluded, thereby ensuring the accuracy of the verification. In FIG. 2, at T ₀ To T ₁ Meanwhile, the fluctuating system pressure represents several exhaust treatment fluid injection cycles that the verification module 115 controls the nozzle 103 to perform.

Optionally, in other partial embodiments, the exhaust aftertreatment system 100 further comprises a liquid level sensor 117 (fig. 1) arranged in the tank 2 of the vehicle and configured to sense a liquid level of the exhaust treatment liquid in the tank 2. The verification module 115 is further configured to control the level sensor 117 to measure a change in the level of the off-gas treatment liquid in the tank 2 during the pressurization step to determine whether the first amount is accurate. In this way, the accuracy of the verification can be further improved.

It should be understood that although the functionality of the verification module 115 has been specifically described above by way of example in which the verification module 115 is integrated in the controller 111 of the exhaust aftertreatment system 100, the verification module 115 may also be integrated in the ECU of the vehicle and the ECU may also be used to control the exhaust aftertreatment system 100 without a separate DCU. Alternatively, the verification module 115 may be integrated in a separate detector for the exhaust aftertreatment system, such as an off-board vehicle (EOL) detector, which may establish communication with the controller 111 of the exhaust aftertreatment system 100 or the ECU of the vehicle to control the pressure sensor 113, the supply unit 105 and the nozzles 103 to perform the above-described verification.

Accordingly, the present application also provides a method for validating an exhaust aftertreatment system 100, including those steps as described above in connection with the validation module 115. Specifically, the method comprises performing the following steps in each verification cycle in turn by controlling the pressure sensor 113, the supply unit 105 and the nozzle 103: (1) A pressure build-up step of closing the nozzle 103 and controlling the supply unit 105 to supply the exhaust treatment liquid from the tank 2 to the supply line 109 to build up a first system pressure P in the supply line 109 ₁ (ii) a (2) A pressurization step of keeping the nozzle 103 closed and controlling the supply unit 109 to continuously supply the first amount of the exhaust gas treatment liquid from the tank 2 to the supply line 109; (3) An injection step of closing the supply unit 105 and controlling the nozzle 103 to open for continuously injecting the first amount of the exhaust gas treatment liquid into the nozzle 103 to return the system pressure in the supply line 109 to the first system pressure P ₁ The theoretical time of (c); (4) A verification step of keeping the supply unit 109 closed and closing the nozzle 103, and of keeping the second system pressure P in the supply line 109 after the injection step ₂ With a first system pressure P ₁ A comparison is made to verify whether the jettability of the nozzle 103 deviates from the design jettability.

Optionally, in some other embodiments, the method further comprises controlling the supply unit 109 to supply the off-gas treatment liquid from the storage tank 2 to the supply line 109 and controlling the nozzle 103 to spray the off-gas treatment liquid to exhaust the gas in the supply line 109 before performing the verification cycle. This may be performed in case the nozzle 103 is first installed or replaced, or in case there is gas in the supply line 109 just when the vehicle is started. In this way, the influence of the gas in the supply line 109 on the verification result can be excluded, thereby ensuring the accuracy of the verification.

Optionally, in some other embodiments, the method further comprises controlling the liquid level sensor 117 to measure a change in the liquid level of the off-gas treatment liquid in the tank 2 during the pressurizing step to determine whether the first amount is accurate. In this way, the accuracy of the verification can be further improved.

Optionally, the method may include performing at least one verification cycle when the nozzle 103 is first installed or replaced for the exhaust aftertreatment system 100. Second system pressure P during each verification cycle ₂ With a first system pressure P ₁ When the difference is within a predetermined range, the number of orifices of the nozzle 103 is determined to match the design orifice number. Second system pressure P during each verification cycle ₂ Above the first system pressure P ₁ Exceeding a first predetermined threshold Δ P _H It is determined that the number of orifices of the nozzle 103 is lower than the design orifice number. While the second system pressure P is maintained during each verification cycle ₂ Below the first system pressure P ₁ Exceeding a second predetermined threshold Δ P _L It is determined that the number of orifices of the nozzle 103 exceeds the design orifice number.

Optionally, the method may include performing at least one verification cycle when the nozzle has been in operation for a certain time (e.g., hundreds or thousands of hours) or for a certain number of firings (e.g., tens or hundreds of thousands of firing cycles). The second system pressure P during each verification cycle ₂ With a first system pressure P ₁ When the difference is within a predetermined range, it is determined that the nozzle is free of leakage and partial clogging. Second system pressure P during each verification cycle ₂ Higher than the first system pressure P ₁ Exceeding a first predetermined threshold Δ P _H When the nozzle is partially clogged, it is determined that the nozzle is partially clogged. Second system pressure P during each verification cycle ₂ Lower than the first system pressure P ₁ Exceeding a second predetermined threshold Δ P _L It is determined that there is a leak in the nozzle.

It should be appreciated that the above-described methods may be executable program instructions stored on a machine-readable non-volatile storage medium. It will also be appreciated that the controller 111, ECU or diagnostic device of the vehicle described above may have a memory and a processor, wherein the memory may store executable program instructions that when executed cause the processor to implement the method described above.

It should also be understood that although in the embodiment shown in fig. 1 there is only a supply line 109 between the supply unit 105 and the nozzle 103, in some other embodiments a return line (not shown) may be connected as a branch to the supply line 109 for conveying part of the off-gas treatment liquid back to the storage tank 2. A return pump is usually arranged on the return line, which can also be regarded as part of the supply unit 105. In this case, the return pump is normally kept off during the verification to avoid affecting the system pressure in the supply line 109.

It will also be understood that the terms "first," "second," and "third" are used merely to distinguish one item from another, but these items should not be limited by such terms.

The present application is described in detail above with reference to specific embodiments. It is to be understood that both the foregoing description and the embodiments shown in the drawings are intended to be exemplary and not restrictive of the application. It will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit of the application, and these changes and modifications do not depart from the scope of the application.

Claims

1. A validation module (115) for an exhaust gas after treatment system comprising a nozzle (103) configured to spray an exhaust gas treatment liquid into an exhaust pipe of a vehicle, a supply unit (105) configured to be arranged between a tank for storing an exhaust gas treatment liquid of a vehicle and the nozzle (103) and to supply the exhaust gas treatment liquid to the nozzle (103), a supply line (109) connected between the supply unit (105) and the nozzle (103), and a pressure sensor (113) configured to sense a system pressure in the supply line (109), the validation module (115) being configured to perform the following steps in each validation cycle in turn by controlling the pressure sensor (113), the supply unit (105) and the nozzle (103):

a pressure building step of closing the nozzle (103) and controlling the supply unit (105) to supply the off-gas treatment liquid from the storage tank to the supply line (109) to build a first system pressure in the supply line (109);

a pressurization step of keeping the nozzle (103) closed and controlling the supply unit (105) to continuously supply a first amount of the exhaust gas treatment liquid from the storage tank to the supply pipeline (109);

an injection step of closing the supply unit (105) and controlling the nozzle (103) to be opened for a theoretical time that allows the nozzle (103) to inject the first amount of the exhaust gas treatment liquid to return the system pressure in the supply line (109) to the first system pressure;

a verification step of keeping the supply unit (105) closed and closing the nozzle (103) and comparing a second system pressure in the supply line (109) with the first system pressure to verify whether the ejection capacity of the nozzle (103) deviates from a design ejection capacity.

2. The verification module (115) of claim 1, wherein:

the validation module (115) is further configured to control the supply unit (105) to supply an off-gas treatment liquid from the storage tank to the supply line (109) and to control the nozzle (103) to spray off-gas treatment liquid to exhaust gas in the supply line (109) before performing the validation cycle; and/or

The exhaust gas after-treatment system further comprises a level sensor arranged in the tank and configured to sense a level of exhaust gas treatment liquid in the tank, the verification module (115) further being configured to control the level sensor to measure a change in the level of exhaust gas treatment liquid in the tank in the step of pressurizing to determine whether the first quantity is accurate.

3. The validation module (115) of claim 1, wherein in the pressurization step, the supply of the first amount of exhaust treatment fluid to the supply line (109) causes a system pressure in the supply line (109) to rise from the first system pressure to a third system pressure, the theoretical time being a time that the nozzle (103) has elapsed to open to inject the first amount of exhaust treatment fluid from being at the third system pressure if an injection capacity of the nozzle (103) meets a design injection capacity.

4. The verification module (115) of any one of claims 1 to 3, wherein after the verification module (115) performs at least one of the verification cycles, the jettability of the nozzle (103) is determined to correspond to a design jettability when a difference between the second system pressure and the first system pressure is within a predetermined range in each of the verification cycles, the jettability of the nozzle (103) is determined to be too low compared to the design jettability when the second system pressure is higher than the first system pressure by more than a first predetermined threshold value in each of the verification cycles, and the jettability of the nozzle (103) is determined to be too high compared to the design jettability when the second system pressure is lower than the first system pressure by more than a second predetermined threshold value in each of the verification cycles.

5. A controller (117) for an exhaust aftertreatment system, wherein the verification module (115) according to claims 1 to 4 is integrated into the controller (117).

6. A meter for an exhaust gas after-treatment system, wherein a validation module (115) according to claims 1 to 4 is integrated into the meter.

7. A method for validating an exhaust gas after-treatment system comprising a nozzle (103) configured to spray an exhaust gas treatment liquid into an exhaust pipe of a vehicle, a supply unit (105) configured to be arranged between a tank for storing an exhaust gas treatment liquid of a vehicle and the nozzle (103) and configured to supply the exhaust gas treatment liquid to the nozzle (103), a supply line (109) connected between the supply unit (105) and the nozzle (103), and a pressure sensor (113) configured to sense a system pressure in the supply line (109), the method comprising performing the following steps in each validation cycle in turn by controlling the pressure sensor (113), the supply unit (105) and the nozzle (103):

a pressure build-up step of closing the nozzle (103) and controlling the supply unit (105) to supply the off-gas treatment liquid from the storage tank to the supply line (109) to build up a first system pressure in the supply line (109);

a pressurization step of keeping the nozzle (103) closed and controlling the supply unit (105) to continuously supply a first amount of the tail gas treatment liquid from the storage tank to the supply pipeline (109);

an injection step of closing the supply unit (105) and controlling the nozzle (103) to be opened for a theoretical time that the nozzle (103) injects the first amount of the exhaust gas treatment liquid to return the system pressure in the supply line (109) to the first system pressure;

8. The method of claim 7, wherein:

the method further comprises controlling the supply unit (105) to supply an off-gas treatment liquid from the storage tank to the supply line (109) and controlling the nozzle (103) to spray the off-gas treatment liquid to exhaust gas in the supply line (109) before performing the validation cycle; and/or

The exhaust gas after-treatment system further comprises a level sensor arranged in the tank and configured to sense a level of exhaust gas treatment liquid in the tank, the method further comprising controlling the level sensor to measure a change in the level of exhaust gas treatment liquid in the tank in the pressurizing step to determine whether the first amount is accurate.

9. A method according to claim 7, characterized in that in the pressurisation step, the supply of the first amount of exhaust gas treatment liquid to the supply line (109) causes the system pressure in the supply line (109) to rise from the first system pressure to a third system pressure, the theoretical time being the time that the nozzle (103) has elapsed from being at the third system pressure to open to inject the first amount of exhaust gas treatment liquid, if the injection capacity of the nozzle (103) corresponds to a design injection capacity.

10. The method according to any one of claims 7 to 9, characterized in that:

the method comprises performing at least one of said verification cycles when a nozzle (103) is first installed or replaced (103) for said exhaust aftertreatment system, determining that a number of orifices of said nozzle (103) corresponds to a design orifice number when a difference between said second system pressure and said first system pressure in each of said verification cycles is within a predetermined range, determining that a number of orifices of said nozzle (103) is below a design orifice number when said second system pressure is above said first system pressure above a first predetermined threshold in each of said verification cycles, and determining that a number of orifices of said nozzle (103) exceeds a design orifice number when said second system pressure is below said first system pressure above a second predetermined threshold in each of said verification cycles; and/or

The method comprises performing at least one of said verification cycles when said nozzle (103) has been operated for a certain time or injected a certain number of times, determining that there is no leakage and partial clogging of said nozzle (103) when the difference between said second system pressure and said first system pressure in each of said verification cycles is within a predetermined range, determining that there is partial clogging of said nozzle (103) when said second system pressure is higher than said first system pressure above a first predetermined threshold in each of said verification cycles, determining that there is a leakage of said nozzle (103) when said second system pressure is lower than said first system pressure above a second predetermined threshold in each of said verification cycles.