CN110886640A

CN110886640A - NO (nitric oxide)xOverproof judgment method, device and system

Info

Publication number: CN110886640A
Application number: CN201910944132.2A
Authority: CN
Inventors: 王孝莉; 王军; 王远景; 耿磊; 赵龙龙
Original assignee: Weichai Power Co Ltd; Weichai Power Emission Solutions Technology Co Ltd
Current assignee: Weichai Power Co Ltd; Weichai Power Emission Solutions Technology Co Ltd
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2020-03-17

Abstract

The embodiment of the invention provides a method, a device and a system for judging NOx exceeding, wherein the method controls the current urea injection quantity to be a first preset value when a NOx exceeding instruction is received. And then, acquiring a current NOx value, judging whether the current NOx value is larger than a second preset value, if so, determining that the current NOx value exceeds the standard, and if not, determining that the current NOx value exceeds the standard, namely, NH 3. Therefore, according to the scheme, when the NOx exceeding standard is detected, the current urea injection amount is controlled, then the current NOx value is detected, whether the NOx exceeding standard is caused by excessive ammonia gas or not is judged, and the accuracy of NOx content detection is improved.

Description

NO (nitric oxide)xOverproof judgment method, device and system

Technical Field

The invention relates to the technical field of emission detection, in particular to a method, a device and a system for judging NOx standard exceeding.

Background

At present, the nitrogen-oxygen sensor is adopted to detect the content of NOx in the tail gas, but the inventor finds that due to cross sensitivity of the nitrogen-oxygen sensor, a part of ammonia gas can be mistakenly detected into NOx during operation, so that the detected content of NOx is inaccurate.

That is, when NOx in the exhaust gas is detected to be out of standard by the NOx sensor during the running of the vehicle, it may be that the NOx gas in the exhaust gas is out of standard or that NOx is out of standard due to ammonia leakage for some reasons.

Therefore, how to provide a method for determining NOx overproof can improve the accuracy of detection is a great technical problem to be solved urgently by those skilled in the art.

Disclosure of Invention

In view of this, the embodiment of the present invention provides a method for determining an NOx exceeding standard, which can improve accuracy of detection.

In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:

a NOx excessive determination method comprising:

when an NOx standard exceeding instruction is received, controlling the current urea injection quantity to be a first preset value;

and acquiring a current NOx value, judging whether the current NOx value is larger than a second preset value, if so, determining that the current NOx value exceeds the standard, and if not, determining that the current NOx value exceeds the standard, namely, NH 3.

Optionally, the controlling the current urea injection amount to be a first preset value includes:

the current urea injection amount is controlled to be α times the normal urea injection amount.

Optionally, according to a formula

Calculating a urea injection quantity coefficient, wherein α is the urea injection quantity coefficient, N1 is the OBD limit value of the national six-diesel engine NOx, N2 is the national six-NOx emission regulation limit value, and N0 is a preset original engineA NOx emission value.

Optionally, the method further includes:

when it is determined that the current NOx exceeds the standard, an alarm is triggered.

Optionally, the method further includes:

acquiring a NOx detection value;

and when the NOx detection value is larger than an OBD limit value, triggering the NOx exceeding instruction.

An NOx excessive determination device comprising:

the control module is used for controlling the current urea injection quantity to be a first preset value when receiving an NOx standard exceeding instruction;

and the judging module is used for acquiring the current NOx value, judging whether the current NOx value is larger than a second preset value or not, if so, determining that the current NOx exceeds the standard, and if not, determining that the NH3 exceeds the standard.

Optionally, the control module includes:

a control unit for controlling the current urea injection quantity to α times the normal urea injection quantity, wherein,

α is the urea injection quantity coefficient, N1 is the OBD limit value of the national six-diesel engine NOx, N2 is the national six-NOx emission regulation limit value, and N0 is the preset original engine NOx emission value.

Optionally, the method further includes:

an alert module to trigger an alert when the current NOx is determined to be out of specification.

Optionally, the method further includes:

the acquisition module is used for acquiring a NOx detection value;

and the triggering module is used for triggering the NOx standard exceeding instruction when the NOx detection value is larger than the OBD limit value.

An NOx excessive determination system comprising any one of the above NOx excessive determination devices.

Based on the technical scheme, the embodiment of the invention provides a method, a device and a system for judging the NOx exceeding standard. And then, acquiring a current NOx value, judging whether the current NOx value is larger than a second preset value, if so, determining that the current NOx value exceeds the standard, and if not, determining that the current NOx value exceeds the standard, namely, NH 3. Therefore, according to the scheme, when the NOx exceeding standard is detected, the current urea injection amount is controlled, then the current NOx value is detected, whether the NOx exceeding standard is caused by excessive ammonia gas or not is judged, and the accuracy of NOx content detection is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic flow chart illustrating a method for determining NOx exceeding according to the present embodiment;

FIG. 2 is a schematic flow chart illustrating a method for determining excessive NOx emissions according to the present embodiment;

FIG. 3 is a schematic flow chart illustrating a method for determining excessive NOx emissions according to the present embodiment;

FIG. 4 is a schematic flow chart illustrating a method for determining excessive NOx emissions according to the present embodiment;

FIG. 5 is a schematic flow chart illustrating a method for determining excessive NOx emissions according to the present embodiment;

fig. 6 is a schematic structural diagram of an NOx excessive determination device according to the present embodiment;

fig. 7 is a schematic view showing still another structure of an NOx excessive determination device according to the present embodiment;

fig. 8 is a schematic view showing still another structure of an NOx excessive determination device according to the present embodiment;

fig. 9 is a schematic diagram showing still another structure of the NOx excessive determination device according to the present embodiment.

Detailed Description

As described by way of background, the inventors contemplate:

if the NOx gas is out of limit, the reason may be that the original emission of the diesel engine is too high, and the problem of the catalytic system may also be caused.

If the amount of ammonia is large, the ammonia may be caused by factors such as deviation or malfunction of the urea injection system.

Therefore, the invention provides the NOx overproof judging method, which is used for judging whether the NOx value overproof measured by the nitrogen-oxygen sensor is caused by excessive ammonia gas or not, so that the fault reason is preliminarily determined, and the rapid and targeted solution is facilitated.

Referring to fig. 1, fig. 1 is a schematic flow chart of a method for determining NOx exceeding according to the present embodiment, including the steps of:

s11, when the NOx standard exceeding instruction is received, controlling the current urea injection quantity to be a first preset value;

s12, obtaining a current NOx value, judging whether the current NOx value is larger than a second preset value, if so, determining that the current NOx exceeds the standard, and if not, determining that the current NOx exceeds the standard, namely NH 3.

It can be seen that, in the embodiment, after the NOx detected by the nitrogen oxygen sensor exceeds the standard (when the NOx exceeding instruction is received), whether the NOx still exceeds the OBD limit value is detected by adjusting the urea injection amount, and if the measurement result is no longer exceeded, it is indicated that the reason for causing the NOx exceeding is excessive ammonia in the exhaust gas, and a targeted investigation needs to be performed.

That is, the NOx exceeding judgment method provided by the embodiment can judge in time whether the measured value of the NOx sensor exceeds the standard due to excessive ammonia gas or excessive NOx.

Specifically, as shown in fig. 2, the embodiment provides a specific implementation manner for controlling the current urea injection amount to be the first preset value, and includes the following steps:

and S21, controlling the current urea injection quantity to be α times of the normal urea injection quantity.

Where α is the urea injection quantity coefficient, in this embodiment, it is checked whether NOx still exceeds the OBD limit by reducing the urea injection quantity, and therefore α is less than 1.

Specifically, as illustrated in fig. 3, the present implementation also provides a way to calculate α, as follows:

s31, according to the formula

And calculating the urea injection quantity coefficient.

Wherein α is the urea injection quantity coefficient, N1 is the OBD limit of national six diesel engine NOx, N2 is the national six NOx emission regulation limit, and N0 is the preset original engine NOx emission value.

Specifically, the inventor considers that the coefficient α cannot be too large or too small, and therefore, the calculation formula is shown in formula 1, wherein N0 is the original engine NOx emission result, and data are obtained by bench tests in the calibration process and are in g/(kw.h), N1 is the OBD limit value of the national six diesel engine NOx and can be 1.2g/(kw.h), and N2 is the national six NOx emission regulation limit value and can be 0.46 g/(kw.h).

Besides, on the basis of the above embodiment, as shown in fig. 4, the NOx exceeding determination method according to the embodiment of the present invention may further include:

and S41, triggering an alarm when the current NOx is determined to be over-standard.

That is, in the embodiment, when the NOx exceeding instruction is received, an alarm is not given, but whether the NOx value exceeding standard measured by the nitrogen oxygen sensor is caused by excessive ammonia gas is firstly judged, so that the fault reason is preliminarily determined, and quick and targeted solution is facilitated.

Specifically, the inventor considers that the reason is not easy to determine if the NOx exceeds the standard at present, and the NOx can only be checked one by one through experience. Therefore, according to the embodiment of the invention, under the condition of the over-standard NOx fault, whether the NOx is still over-standard or not is judged by adjusting the urea injection amount, if not, the over-standard NOx value measured by the nitrogen oxygen sensor caused by excessive ammonia gas can be judged, if the over-standard NOx value is still over-standard, the less-injection urea does not work, and the over-standard NOx value measured by the nitrogen oxygen sensor caused by excessive NOx is over-standard. Therefore, the checking direction can be preliminarily determined, and the checking efficiency is improved.

Further, an embodiment of the present invention provides a control condition for triggering the NOx exceeding command, as shown in fig. 5, including the steps of:

s51, acquiring a NOx detection value;

and S52, when the NOx detection value is larger than the OBD limit value, triggering the NOx exceeding instruction.

The method for judging whether the NOx exceeds the standard is the same as the prior art, the method is used for detecting the NOx value, and when the detected value is larger than the OBD limit value, an NOx exceeding instruction is triggered.

On the basis of the above-described embodiment, as shown in fig. 6, an embodiment of the present invention also provides an NOx excessive determination device including:

the control module 61 is used for controlling the current urea injection amount to be a first preset value when receiving an NOx standard exceeding instruction;

and the judging module 62 is configured to obtain a current NOx value, judge whether the current NOx value is greater than a second preset value, determine that the current NOx exceeds the standard if the current NOx value is greater than the second preset value, and determine that the NH3 exceeds the standard if the current NOx value is not greater than the second preset value.

In addition, as shown in fig. 7, the control module 61 includes:

and a control unit 71 for controlling the current urea injection quantity to α times the normal urea injection quantity.

Wherein the content of the first and second substances,

On the basis of the above embodiment, as shown in fig. 8, the NOx exceeding determination device according to the embodiment of the present invention may further include:

an alarm module 81 for triggering an alarm when it is determined that the current NOx exceeds a standard.

In addition, as shown in fig. 9, the NOx exceeding determination device according to the embodiment of the present invention may further include:

an obtaining module 91, configured to obtain a NOx detection value;

and the triggering module 92 is configured to trigger the NOx exceeding instruction when the NOx detection value is greater than an OBD limit value.

The working principle of the device is shown in the embodiment of the method, which is that: under the condition that the NOx exceeds the standard and reports the fault, whether the NOx still exceeds the standard or not is judged by adjusting the urea injection quantity, if not, the NOx value measured by the nitrogen oxygen sensor is judged to be too high due to excessive ammonia gas, if the NOx still exceeds the standard, the less-injection urea does not work, and if the NOx still exceeds the standard, the NOx value measured by the nitrogen oxygen sensor is excessive due to excessive NOx. Therefore, the checking direction can be preliminarily determined, and the checking efficiency is improved.

In addition, the embodiment of the present invention further provides an NOx exceeding judgment system, which includes any one of the above NOx exceeding judgment devices, and the working principle of the NOx exceeding judgment device refers to the above method embodiment, which will not be described repeatedly herein.

In summary, the embodiments of the present invention provide a method, an apparatus, and a system for determining that NOx exceeds a standard, where the method controls a current urea injection amount to be a first preset value when receiving an NOx exceeding instruction. And then, acquiring a current NOx value, judging whether the current NOx value is larger than a second preset value, if so, determining that the current NOx value exceeds the standard, and if not, determining that the current NOx value exceeds the standard, namely, NH 3. Therefore, according to the scheme, when the NOx exceeding standard is detected, the current urea injection amount is controlled, then the current NOx value is detected, whether the NOx exceeding standard is caused by excessive ammonia gas or not is judged, and the accuracy of NOx content detection is improved.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A NOx excessive determination method, characterized by comprising:

2. The NOx excessive determination method according to claim 1, wherein the controlling of the current urea injection amount to a first preset value includes:

3. The NOx excessive determination method according to claim 2, characterized in that:

according to the formula

And calculating a urea injection quantity coefficient, wherein α is the urea injection quantity coefficient, N1 is the OBD limit value of the NOx of the national six-diesel engine, N2 is the emission regulation limit value of the national six-NOx, and N0 is a preset original NOx emission value.

4. The NOx overproof determination method according to claim 1, characterized by further comprising:

5. The NOx overproof determination method according to claim 1, characterized by further comprising:

acquiring a NOx detection value;

6. An NOx excessive determination device, characterized by comprising:

7. The NOx excessive determination device according to claim 6, characterized in that the control module includes:

8. The NOx excessive determination device according to claim 6, characterized by further comprising:

9. The NOx excessive determination device according to claim 6, characterized by further comprising:

the acquisition module is used for acquiring a NOx detection value;

10. An NOx excessive determination system characterized by comprising the NOx excessive determination apparatus according to any one of claims 6 to 9.