CN113217158A - Method, system and medium for monitoring and controlling exhaust emission state of engine - Google Patents

Abstract

The invention provides a method, a system and a medium for monitoring and controlling the exhaust emission state of an engine, wherein the method comprises the following steps: establishing a temperature normal mark, a first temperature abnormal mark, a second temperature abnormal mark, a back pressure normal mark, a back pressure abnormal mark, a bypass valve closed state mark and a bypass valve open state mark; monitoring the running states of the tail gas treatment system and the engine in real time, and judging whether to output a control signal for opening or closing a bypass valve according to a current temperature normal mark, a first temperature abnormal mark, a second temperature abnormal mark, a back pressure normal mark, a back pressure abnormal mark, a bypass valve closing state mark and a bypass valve opening state mark; the invention can quickly and accurately judge whether to output the control signal of the bypass valve or not and output which control signal of the bypass valve to control the closing or opening of the bypass valve based on the marks, thereby reducing the generation of toxic gas.

Description

Method, system and medium for monitoring and controlling exhaust emission state of engine

Technical Field

The invention relates to the technical field of engine tail gas treatment, in particular to a method, a system and a medium for monitoring and controlling an engine tail gas emission state.

Background

With the increasingly deep idea of environmental protection, the requirements on the exhaust emission treatment of various large engines are more and more strict. Before being discharged, various engine exhaust must pass through a corresponding treatment device, and can be discharged into the air only according with the emission requirement. Therefore, the electrical control in the processing device is indispensable, and the electrical control part needs to realize the automatic operation of the whole processing device, reduce human participation to the maximum extent and save the labor cost

However, since the field environment in many applications is severe or the operation of the processing apparatus needs to be paid attention to in real time, the response is timely and accurately made according to the operation state of the processing apparatus. Therefore, in a specific application scenario, the reliability and accuracy of the opening or closing of the bypass valve need to be considered, which requires a reliable and simple monitoring and control method.

In order to solve the above problems, people are always seeking an ideal technical solution.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides a method, a system and a medium for monitoring and controlling the exhaust emission state of an engine.

In order to achieve the purpose, the invention adopts the technical scheme that:

the invention provides a method for monitoring and controlling the exhaust emission state of an engine in a first aspect, which comprises the following steps:

pre-configuring an inlet temperature threshold range, an outlet temperature threshold range and a backpressure threshold range of a pipeline of the tail gas treatment device;

calculating an inlet real-time temperature and an outlet real-time temperature of a tail gas treatment device pipeline, determining whether the inlet real-time temperature of the tail gas treatment device pipeline is within an inlet temperature threshold range and whether the outlet real-time temperature is within an outlet temperature threshold range, establishing a temperature normal mark when the inlet real-time temperature is within the inlet temperature threshold range and the outlet real-time temperature is within the outlet temperature threshold range, establishing a first temperature abnormal mark when the inlet real-time temperature is lower than the minimum value of the inlet temperature threshold range and the outlet real-time temperature is lower than the minimum value of the outlet temperature threshold range, and establishing a second temperature abnormal mark when the inlet real-time temperature is higher than the maximum value of the inlet temperature threshold range and the outlet real-time temperature is higher than the maximum value of the outlet temperature threshold range;

calculating the real-time backpressure pressure of the pipeline of the tail gas treatment device, and determining whether the real-time backpressure pressure of the pipeline of the tail gas treatment device is within a backpressure threshold range, if so, establishing a backpressure normal mark, otherwise, establishing a backpressure abnormal mark;

reading a current state signal of the engine, establishing an engine running state mark when the current state signal of the engine is at a low level, and clearing the engine running state mark if the current state signal of the engine is at the low level; reading a current state signal of the bypass valve, and establishing a closed state flag of the bypass valve when the current state signal of the bypass valve is at a low level, or else establishing an open state flag of the bypass valve;

when the engine running state mark is detected, whether the engine is in an idle starting stage is judged, and when the engine is in the idle starting stage:

generating a first bypass valve opening instruction in response to the obtained bypass valve closed state mark, the first temperature abnormal mark and the back pressure normal mark, and starting timing;

when the opening time set value corresponding to the first opening instruction of the bypass valve is reached, if a bypass valve opening state mark, a first temperature abnormal mark and a back pressure normal mark are obtained, a second opening instruction of the bypass valve is generated; the opening time set value corresponding to the second opening instruction of the bypass valve is larger than the opening time set value corresponding to the first opening instruction of the bypass valve;

when the engine running state mark is detected, whether the engine is in a high-speed running stage is also judged, and when the engine is in the high-speed running stage:

generating a bypass valve third opening instruction in response to the obtained bypass valve closed state mark, the temperature abnormal mark and the back pressure abnormal mark, and starting timing;

when the opening time set value corresponding to the bypass valve third opening instruction is reached, if a bypass valve opening state mark, a temperature abnormal mark and a back pressure abnormal mark are obtained, a bypass valve fourth opening instruction is generated; the opening time set value corresponding to the fourth opening command of the bypass valve is larger than the opening time set value corresponding to the third opening command of the bypass valve;

and when the engine is in an idle starting stage or a high-speed running stage, generating a bypass valve closing instruction in response to the obtained opening state mark of the bypass valve, the first temperature normal mark, the second temperature normal mark and the back pressure normal mark.

When the temperature and the pressure in the tail gas treatment device are normal, the bypass valve is opened to enable the tail gas not to enter the treatment device, and the engine is in a running state, a control signal for closing the bypass valve is output, and the duration is the target set control bypass valve closing time; and conversely, a control signal for opening the bypass valve is output, and the duration is the control bypass valve opening time set by the target.

In a second aspect the present invention provides a system for monitoring and controlling the exhaust emission status of an engine, the system comprising: arranging a first temperature sensor for detecting the temperature of an inlet of a pipeline of the tail gas treatment device, a second temperature sensor for detecting the temperature of an outlet of the pipeline of the tail gas treatment device and a pressure sensor for detecting the back pressure of the pipeline of the tail gas treatment device; the first temperature sensor, the second temperature sensor and the pressure sensor are respectively connected with an engine controller, the engine controller is connected with a bypass valve in a control mode, and the bypass valve is configured to be in a closed state in advance;

the engine controller is provided with a temperature monitoring module, a backpressure monitoring module, an engine state monitoring module, a bypass valve state monitoring module and a valve control instruction generating module, and an inlet temperature threshold range, an outlet temperature threshold range and a backpressure threshold range of a tail gas treatment device pipeline are preconfigured;

the temperature monitoring module is used for calculating the inlet real-time temperature and the outlet real-time temperature of the pipeline of the tail gas treatment device, determining whether the inlet real-time temperature of the pipeline of the tail gas treatment device is within the inlet temperature threshold range and whether the outlet real-time temperature is within the outlet temperature threshold range, establishing a temperature normality flag when an inlet real-time temperature is within the inlet temperature threshold range and an outlet real-time temperature is within the outlet temperature threshold range, establishing a first temperature anomaly flag when an inlet real-time temperature is below a minimum of the inlet temperature threshold range and an outlet real-time temperature is below a minimum of the outlet temperature threshold range, establishing a second temperature anomaly flag when the inlet real-time temperature is greater than the maximum of the inlet temperature threshold range and the outlet real-time temperature is greater than the maximum of the outlet temperature threshold range;

the backpressure monitoring module is used for calculating the real-time backpressure of the pipeline of the tail gas treatment device and determining whether the real-time backpressure of the pipeline of the tail gas treatment device is within a backpressure threshold range, if so, establishing a backpressure normal mark, and otherwise, establishing a backpressure abnormal mark;

the engine state monitoring module is used for reading a current state signal of the engine, establishing an engine running state mark when the current state signal of the engine is at a low level, and clearing the engine running state mark if the current state signal of the engine is at the low level;

the bypass valve state monitoring module is used for reading a current state signal of the bypass valve, establishing a bypass valve closed state mark when the current state signal of the bypass valve is at a low level, and otherwise establishing a bypass valve open state mark;

the valve control instruction generation module is used for judging whether the engine is in an idle starting stage or not when the engine running state mark is detected, and when the engine is in the idle starting stage: generating a first bypass valve opening instruction in response to the obtained bypass valve closed state mark, the first temperature abnormal mark and the back pressure normal mark, and starting timing; when the opening time set value corresponding to the first opening instruction of the bypass valve is reached, if a bypass valve opening state mark, a first temperature abnormal mark and a back pressure normal mark are obtained, a second opening instruction of the bypass valve is generated;

the valve control instruction generation module is further used for judging whether the engine is in a high-speed operation stage or not when the engine operation state mark is detected, and when the engine is in the high-speed operation stage: generating a bypass valve third opening instruction in response to the obtained bypass valve closed state mark, the temperature abnormal mark and the back pressure abnormal mark, and starting timing; when the opening time set value corresponding to the bypass valve third opening instruction is reached, if a bypass valve opening state mark, a temperature abnormal mark and a back pressure abnormal mark are obtained, a bypass valve fourth opening instruction is generated;

the valve control instruction generating module is further used for responding to the obtained opening state mark of the bypass valve, the first temperature normal mark, the second temperature normal mark and the back pressure normal mark when the engine is in an idle starting stage or a high-speed running stage, and generating a bypass valve closing instruction.

A third aspect of the present invention provides a computer-readable storage medium having stored thereon a computer program which, when being executed by a processor, carries out the steps of the method for monitoring and controlling an exhaust emission state of an engine as described above.

Compared with the prior art, the invention has prominent substantive characteristics and remarkable progress, particularly:

1) according to the invention, a temperature normal mark, a first temperature abnormal mark, a second temperature abnormal mark, a back pressure normal mark, a back pressure abnormal mark, an engine running state mark, a bypass valve closing state mark and a bypass valve opening state mark are established firstly, and a bypass valve control signal is updated based on the marks, so that whether the bypass valve control signal is output or not is judged quickly and accurately, and what kind of bypass valve control signal is output to control the bypass valve to be closed or opened, and the generation of toxic gas is reduced;

2) when a control signal of the bypass valve is output, whether the bypass valve is successfully closed or opened is also judged to establish a bypass valve closing failure alarm sign or a bypass valve opening failure alarm sign to prevent misoperation;

3) the method comprises the steps of calculating a first filtering result by using a pre-constructed inlet temperature filtering model, calculating an electric parameter corresponding to the first filtering result according to a calculation formula corresponding to a temperature sensor, and obtaining inlet real-time temperature based on the electric parameter and a preset sensor curve, so that the condition that more noise signals are remained in a control signal due to incomplete filtration of original data is avoided, and the accuracy of subsequent valve control is improved.

Drawings

FIG. 1 is a flow chart of a method of monitoring and controlling exhaust emission status of an engine according to the present invention;

FIG. 2 is a flow chart of valve control command generation according to the present invention;

FIG. 3 is a bypass valve response status confirmation flow diagram of the present invention;

FIG. 4 is a schematic of the inlet real time temperature, outlet real time temperature and real time backpressure pressure calculations of the present invention;

FIG. 5 is a sampling circuit diagram of the multi-function multiplexing sensor of the present invention;

FIG. 6 is a diagram of an equivalent sampling circuit for a resistive sensor of the present invention;

FIG. 7 is a schematic diagram of an equivalent sampling circuit of the current mode sensor of the present invention;

fig. 8 is an equivalent sampling circuit diagram of the voltage mode sensor of the present invention.

Detailed Description

The technical solution of the present invention is further described in detail by the following embodiments.

Example 1

As shown in fig. 1 and 2, a method for monitoring and controlling an exhaust emission state of an engine includes the steps of:

a preparation stage:

arranging a first temperature sensor for detecting the temperature of an inlet of a pipeline of the tail gas treatment device, a second temperature sensor for detecting the temperature of an outlet of the pipeline of the tail gas treatment device and a pressure sensor for detecting the back pressure of the pipeline of the tail gas treatment device; the first temperature sensor, the second temperature sensor and the pressure sensor are respectively connected with an engine controller, the engine controller is connected with a bypass valve in a control mode, and the bypass valve is configured to be in a closed state in advance;

pre-configuring an inlet temperature threshold range, an outlet temperature threshold range and a backpressure threshold range of a pipeline of the tail gas treatment device;

calculating an inlet real-time temperature and an outlet real-time temperature of a tail gas treatment device pipeline, determining whether the inlet real-time temperature of the tail gas treatment device pipeline is within an inlet temperature threshold range and whether the outlet real-time temperature is within an outlet temperature threshold range, establishing a temperature normal mark when the inlet real-time temperature is within the inlet temperature threshold range and the outlet real-time temperature is within the outlet temperature threshold range, establishing a first temperature abnormal mark when the inlet real-time temperature is lower than the minimum value of the inlet temperature threshold range and the outlet real-time temperature is lower than the minimum value of the outlet temperature threshold range, and establishing a second temperature abnormal mark when the inlet real-time temperature is higher than the maximum value of the inlet temperature threshold range and the outlet real-time temperature is higher than the maximum value of the outlet temperature threshold range;

calculating the real-time backpressure pressure of the pipeline of the tail gas treatment device, and determining whether the real-time backpressure pressure of the pipeline of the tail gas treatment device is within a backpressure threshold range, if so, establishing a backpressure normal mark, otherwise, establishing a backpressure abnormal mark;

reading a current state signal of the engine, establishing an engine running state mark when the current state signal of the engine is at a low level, and clearing the engine running state mark if the current state signal of the engine is at the low level; reading a current state signal of the bypass valve, and establishing a closed state flag of the bypass valve when the current state signal of the bypass valve is at a low level, or else establishing an open state flag of the bypass valve;

when the engine running state mark is detected, whether the engine is in an idle starting stage is judged, and when the engine is in the idle starting stage:

generating a first bypass valve opening instruction in response to the obtained bypass valve closed state mark, the first temperature abnormal mark and the back pressure normal mark, and starting timing;

when the opening time set value corresponding to the first opening instruction of the bypass valve is reached, if a bypass valve opening state mark, a first temperature abnormal mark and a back pressure normal mark are obtained, a second opening instruction of the bypass valve is generated; the opening time set value corresponding to the second opening instruction of the bypass valve is larger than the opening time set value corresponding to the first opening instruction of the bypass valve;

when the engine running state mark is detected, whether the engine is in a high-speed running stage is also judged, and when the engine is in the high-speed running stage:

generating a bypass valve third opening instruction in response to the obtained bypass valve closed state mark, the temperature abnormal mark and the back pressure abnormal mark, and starting timing;

when the opening time set value corresponding to the bypass valve third opening instruction is reached, if a bypass valve opening state mark, a temperature abnormal mark and a back pressure abnormal mark are obtained, a bypass valve fourth opening instruction is generated; the opening time set value corresponding to the fourth opening command of the bypass valve is larger than the opening time set value corresponding to the third opening command of the bypass valve;

and when the engine is in an idle starting stage or a high-speed running stage, generating a bypass valve closing instruction in response to the obtained opening state mark of the bypass valve, the first temperature normal mark, the second temperature normal mark and the back pressure normal mark.

The idle starting phase refers to a time period from establishment of an engine running state mark (an engine current state signal is changed from invalid to valid), an inlet real-time temperature of a pipeline of the exhaust gas treatment device is changed from a minimum value smaller than an inlet temperature threshold range to be within the inlet temperature threshold range, and an outlet real-time temperature is changed from a minimum value smaller than the inlet temperature threshold range to be within the inlet temperature threshold range.

It should be noted that the normal operation of the exhaust gas treatment device in fig. 1 means that the back pressure, the inlet temperature and the outlet temperature in the exhaust gas treatment device are all within the threshold range, and the abnormal operation of the exhaust gas treatment device means that at least one of the back pressure, the inlet temperature and the outlet temperature in the exhaust gas treatment device is not within the threshold range; the bypass valve state is normal, namely the bypass valve is in a normal closed state, and the closed feedback is effective.

In practical applications, although the probability that the engine is operated in other states (except a high-speed operation state) and the conditions that the inlet temperature exceeds the maximum value of the inlet temperature threshold range, the outlet temperature exceeds the maximum value of the outlet temperature threshold range and the back pressure exceeds the maximum value of the back pressure threshold range are detected is very small, once the conditions occur, a bypass valve opening command needs to be generated to release the pressure.

It will be appreciated that the energy required for the operation of the engine results from the combustion of the fuel, the degree of richness of combustion and the temperature of combustion determining the degree of pollution of the exhaust gases. Under the normal running state of the engine, the air inlet temperature of the engine is about 70-80 ℃, and the exhaust temperature is about 600-800 ℃.

Different engines, different operating environments, different carrying capacity, different temperature values and different back pressure values are used; specifically, the threshold range of the inlet temperature is 30-80 ℃, the threshold range of the outlet temperature is 600-1000 ℃, and the threshold range of the back pressure is 0-9000 kPa.

The engine operating state is typically idle-high-idle: when the engine is just started at idle (the process from rest to running of the engine), the temperature of an air inlet of a cylinder is close to normal temperature (the external environment temperature of the engine), and the temperature of an air outlet is less than 600 ℃ (the specific temperature is related to the type, the combustion degree and the loading condition of the engine); at this time, the temperature in the cylinder is lower, the temperature of the fuel gas is also lower, the fuel combustion is insufficient, and the discharged gas contains more pollutants; therefore, at the moment, the bypass valve needs to be opened to increase the air inflow so as to improve the fuel combustion rate;

when the engine is operated at a high speed, the temperature of the cylinder is increased along with the increase of the operation time, and toxic nitrogen oxides NOx are formed due to high temperature and high pressure in the combustion chamber. When the detected temperature and back pressure values are larger than the maximum value of the threshold range, the bypass valve is opened to increase the inflow of air at the air inlet, increase the oxygen intake required by combustion, and reduce the temperature and pressure in the combustion chamber, thereby reducing the generation of toxic gases.

It should be noted that, the opening or closing of the bypass valve is controlled by the forward rotation or the reverse rotation of the motor, the charging time of the motor can be set, and the opening time is set to be larger when the valve is completely opened, and the valve opening is larger when the opening time is set to be larger.

In order to confirm whether the bypass valve responds according to the control signal, the present embodiment detects the current state signal of the bypass valve while outputting the control signal of the bypass valve, and determines whether the bypass valve is successfully closed and successfully opened according to the type of the control signal and the current state of the bypass valve.

As shown in fig. 3, the bypass valve response status confirmation process is as follows:

starting timing when the engine controller outputs a bypass valve control signal; when the first time preset value is reached, executing the following steps: sampling the current state of the bypass valve again, and judging whether the current state of the bypass valve is consistent with the state of the bypass valve corresponding to the control signal of the bypass valve; if the two signals are consistent, judging that the response of the bypass valve is successful, and enabling the engine controller to stop outputting a bypass valve control signal; otherwise, repeatedly executing the steps through a fixed time interval M1 until the output time of the bypass valve control signal is over; when the output time of the bypass valve control signal is over, if the current state of the bypass valve is judged to be inconsistent with the bypass valve state corresponding to the bypass valve control signal again, a bypass valve response failure alarm sign is established;

the bypass valve control signal comprises a first bypass valve opening command, a second bypass valve opening command, a third bypass valve opening command, a fourth bypass valve opening command and a bypass valve closing command.

It should be noted that when the bypass valve opening failure alarm is effective, the controller does not output any control signal any more, so as to avoid causing misoperation; the method specifically comprises the following steps:

determining whether a bypass valve response failure alarm mark is read or not, wherein the bypass valve response failure alarm mark comprises a bypass valve opening failure alarm mark and a bypass valve closing failure alarm mark;

in response to the read bypass valve opening failure alarm mark, the engine controller stops outputting a first bypass valve opening instruction, a second bypass valve opening instruction, a third bypass valve opening instruction and a fourth bypass valve opening instruction;

in response to reading the bypass valve closure failure warning flag, the engine controller stops outputting the bypass valve closure command.

This embodiment provides a specific implementation of calculating the real-time inlet temperature by recursive filtering, as shown in fig. 4; when calculating the real-time temperature of the inlet of the pipeline of the tail gas treatment device, executing the following steps:

acquiring inlet temperature original data of a pipeline of the tail gas treatment device based on a preset temperature sampling time interval (for example, 100 ms), starting an ADC conversion sampling channel, and sequentially placing the inlet temperature original data into a specified inlet temperature buffer area according to a time sequence;

counting the acquired original data volume of the inlet temperature, and when the original data volume of the inlet temperature is equal to a preset temperature sampling filter coefficient (for example, 8), calculating a first filter result D1 by using a pre-constructed inlet temperature filter model; selecting a corresponding calculation formula according to the type of the temperature sensor for acquiring the inlet real-time temperature, calculating an electric parameter corresponding to the first filtering result D1, and acquiring an inlet real-time temperature T1 based on the electric parameter and a preset sensor curve;

after the inlet real-time temperature T1 is obtained, timing is started;

and when new inlet temperature original data are acquired, deleting the first inlet temperature original data in the specified inlet temperature buffer area, placing a new inlet temperature signal in the specified inlet temperature buffer area, repeatedly executing the inlet real-time temperature calculation step, and updating the inlet real-time temperature until the temperature stabilization time delay is finished.

Specifically, the pre-constructed inlet temperature filtering model is as follows: the first filtering result D1 = (Sum-Max-Min)/(Sum-2), where Sum is the Sum of the original data of the inlet temperature, Max is the maximum value of the original data of the inlet temperature, Min is the minimum value of the original data of the inlet temperature, and Sum is the total number of samples, i.e., the preset temperature sampling filter coefficient.

In a specific embodiment, the preset temperature sampling filter coefficient is 8, when the number of the sampled inlet temperature raw data reaches 8, the 8 inlet temperature raw data are subjected to filter processing, and when the 9 th inlet temperature raw data is obtained, the 1 st inlet temperature raw data is deleted, and the 2 nd to 9 th data are subjected to filter processing again.

It should be noted that the specific steps for calculating the real-time outlet temperature are similar to the steps for calculating the real-time inlet temperature, and are not described herein again in this embodiment.

The embodiment also provides a specific implementation of calculating the real-time back pressure by recursive filtering, as shown in fig. 4; when calculating the real-time backpressure pressure of the pipeline of the tail gas treatment device, executing:

acquiring backpressure original data of a pipeline of the tail gas treatment device based on a preset pressure sampling time interval (for example, 100 ms), starting an ADC (analog to digital converter) conversion sampling channel, and sequentially placing the backpressure original data into a specified backpressure buffer area according to a time sequence;

counting the acquired backpressure original data volume, when the backpressure original data volume is equal to a preset backpressure sampling filter coefficient, calculating a second filter result E1 by using a pre-constructed backpressure filter model, selecting a corresponding calculation formula according to the type of a pressure sensor for collecting backpressure, calculating an electric parameter corresponding to the second filter result E1, and obtaining real-time backpressure pressure F1 based on the electric parameter and a preset sensor curve;

after the real-time back pressure F1 is obtained, timing is started;

and when new backpressure original data are obtained, deleting the first backpressure original data in the specified backpressure buffer area, placing the new backpressure original data in the specified backpressure buffer area, repeatedly executing the real-time backpressure pressure calculation step, and updating the real-time backpressure pressure until the backpressure stabilization time delay is finished.

Specifically, the pre-constructed backpressure filter model is consistent with the inlet temperature filter model, and will not be described in detail here.

The embodiment also provides a specific implementation manner of establishing the engine operation state flag:

reading a first switching value detection result, if the first switching value detection result is an effective low level, judging that the engine is in a running state, establishing an engine running state mark, starting timing for S1 time period, and sequentially extracting the first switching value detection result at a fixed time interval N1;

if the first switching value detection result is detected to be an effective high level at least once when the timing of the S1 time period is ended, generating an instruction for clearing the engine running state flag, and starting the timing of the S2 time period;

and extracting the first switching value detection result in the time period of S2 until the time period of S2 is timed out, and if the first switching value detection result in the time period of S2 is all effective high level, judging that the engine is in a stop state, and executing the operation of clearing the engine running state flag.

It can be understood that the step of establishing the engine running state mark can effectively filter interference factors and prevent the engine running state mark from being established by mistake, thereby improving the control accuracy of the valve.

The present embodiment further provides an embodiment of establishing the bypass valve closed status flag or the bypass valve open status flag:

reading a second switching value detection result, if the second switching value detection result is an effective low level, judging that the bypass valve is in a closed state, establishing a bypass valve closed state mark, starting timing in S1 'time period, and sequentially extracting the second switching value detection result at a fixed time interval N1';

if the second switch quantity detection result is detected to be an effective high level at least once when the time period of S1 'is timed to end, generating a command of clearing the bypass valve closed state mark, and starting the time period of S2';

and extracting a second switching value detection result in the time period of S2 'until the time period of S2 is timed out, if the second switching value detection result in the time period of S2' is effective high level, judging that the bypass valve is in an open state, executing the operation of clearing the bypass valve closed state mark, and establishing the bypass valve open state mark.

It can be understood that, the above steps of establishing the bypass valve closed state flag or bypass valve open state flag can effectively filter out interference factors, and prevent the establishment of a wrong bypass valve closed state flag or bypass valve open state flag, thereby further improving the valve control accuracy.

Specifically, the temperature normal flag, the first temperature abnormal flag, the second temperature abnormal flag, the back pressure normal flag, the back pressure abnormal flag, the engine operation state flag, the bypass valve closed state flag, and the bypass valve open state flag may be represented by different ID numbers, and based on these ID numbers, the engine controller quickly and accurately determines whether to output a bypass valve control signal, and what kind of bypass valve control signal to output;

wherein the ID number may be represented by 4 bits of binary data, the first two bits representing the type, e.g., 00 for temperature, 01 for back pressure, 10 for engine, 11 for bypass valve; the last two bits indicate a specific state, for example, 0000 indicates a temperature normal flag, 0001 indicates a first temperature abnormal flag, 0010 indicates a second temperature abnormal flag, 0011 is reserved, 0100 indicates a back pressure normal flag, 0101 indicates a back pressure abnormal flag, 0110 and 0111 are reserved, 1000 indicates an engine operation state flag, 1001 to 1011 are reserved, 1100 indicates a bypass valve closed state flag, 1101 indicates a bypass valve open state flag, 1110 and 1111 are reserved.

Example 2

On the basis of the method for monitoring and controlling the exhaust emission state of the engine in embodiment 1, the embodiment provides a system for monitoring and controlling the exhaust emission state of the engine;

the monitoring and control system includes:

arranging a first temperature sensor for detecting the temperature of an inlet of a pipeline of the tail gas treatment device, a second temperature sensor for detecting the temperature of an outlet of the pipeline of the tail gas treatment device and a pressure sensor for detecting the back pressure of the pipeline of the tail gas treatment device;

the first temperature sensor, the second temperature sensor and the pressure sensor are respectively connected with an engine controller through a multifunctional multiplexing sensor sampling circuit, the engine controller is in control connection with a bypass valve, and the bypass valve is configured in advance to be in a closed state; as shown in fig. 5, the multifunctional multiplexing sensor sampling circuit controls the state of the triode according to the sensor types of the first temperature sensor, the second temperature sensor and the pressure sensor, so that the multifunctional multiplexing sensor sampling circuit is multiplexed into a voltage type, a resistance type or a current type sampling circuit;

the engine controller is provided with a temperature monitoring module, a backpressure monitoring module, an engine state monitoring module, a bypass valve state monitoring module and a valve control instruction generating module, and an inlet temperature threshold range, an outlet temperature threshold range and a backpressure threshold range of a tail gas treatment device pipeline are preconfigured;

the temperature monitoring module is used for calculating the inlet real-time temperature and the outlet real-time temperature of the pipeline of the tail gas treatment device, determining whether the inlet real-time temperature of the pipeline of the tail gas treatment device is within the inlet temperature threshold range and whether the outlet real-time temperature is within the outlet temperature threshold range, establishing a temperature normality flag when an inlet real-time temperature is within the inlet temperature threshold range and an outlet real-time temperature is within the outlet temperature threshold range, establishing a first temperature anomaly flag when an inlet real-time temperature is below a minimum of the inlet temperature threshold range and an outlet real-time temperature is below a minimum of the outlet temperature threshold range, establishing a second temperature anomaly flag when the inlet real-time temperature is greater than the maximum of the inlet temperature threshold range and the outlet real-time temperature is greater than the maximum of the outlet temperature threshold range;

the backpressure monitoring module is used for calculating the real-time backpressure of the pipeline of the tail gas treatment device and determining whether the real-time backpressure of the pipeline of the tail gas treatment device is within a backpressure threshold range, if so, establishing a backpressure normal mark, and otherwise, establishing a backpressure abnormal mark;

the engine state monitoring module is used for reading a current state signal of the engine, establishing an engine running state mark when the current state signal of the engine is at a low level, and clearing the engine running state mark if the current state signal of the engine is at the low level;

the bypass valve state monitoring module is used for reading a current state signal of the bypass valve, establishing a bypass valve closed state mark when the current state signal of the bypass valve is at a low level, and otherwise establishing a bypass valve open state mark;

the valve control instruction generation module is used for judging whether the engine is in an idle starting stage or not when the engine running state mark is detected, and when the engine is in the idle starting stage: generating a first bypass valve opening instruction in response to the obtained bypass valve closed state mark, the first temperature abnormal mark and the back pressure normal mark, and starting timing; when the opening time set value corresponding to the first opening instruction of the bypass valve is reached, if a bypass valve opening state mark, a first temperature abnormal mark and a back pressure normal mark are obtained, a second opening instruction of the bypass valve is generated;

the valve control instruction generation module is further used for judging whether the engine is in a high-speed operation stage or not when the engine operation state mark is detected, and when the engine is in the high-speed operation stage: generating a bypass valve third opening instruction in response to the obtained bypass valve closed state mark, the temperature abnormal mark and the back pressure abnormal mark, and starting timing; when the opening time set value corresponding to the bypass valve third opening instruction is reached, if a bypass valve opening state mark, a temperature abnormal mark and a back pressure abnormal mark are obtained, a bypass valve fourth opening instruction is generated;

the valve control instruction generating module is further used for responding to the obtained opening state mark of the bypass valve, the first temperature normal mark, the second temperature normal mark and the back pressure normal mark when the engine is in an idle starting stage or a high-speed running stage, and generating a bypass valve closing instruction.

It should be noted that the monitoring and control system is a separate control system, and is different from the engine controller system, and the engine controller mainly focuses on the running state of the engine and outputs commands to control the engine; the monitoring and control system of the present embodiment monitors the operating state of the engine, but only serves as a reference, and the main judgment is based on the feedback state of the exhaust gas treatment system.

Specifically, if the first temperature sensor, the second temperature sensor, and the pressure sensor are resistance sensors, the type of the sensor output signal Is resistance, and the dc power supply VREF in fig. 6 forms a loop with R3, R5, and RS, and the current Is in the loop, Is = (U1-U2)/(R3 + R5), according to ohm's law: RS = U2/Is; then the corresponding calculation formula RS = U2/((U1-U2)/(R3 + R5)) of the resistance type sensor, wherein U1 and U2 are obtained by sampling of a single chip microcomputer; at this time, RS is the raw data (inlet temperature, outlet temperature, or back pressure).

If the first temperature sensor, the second temperature sensor and the pressure sensor are current type sensors, the type of the output signal of the sensor is current, and an input current source and R5 form a current loop in fig. 7, according to ohm's law: a calculation formula Is = (U2-U1)/R5 corresponding to the current sensor; wherein U1 and U2 are obtained by sampling through a single chip microcomputer; IS raw data (inlet temperature, outlet temperature or back pressure).

If the first temperature sensor, the second temperature sensor and the pressure sensor are voltage type sensors, the type of the output signal of the sensor is voltage, in fig. 8, 0V is a low level output by the single chip microcomputer, and a calculation formula Us =2 × U2 corresponding to the voltage type sensor is obtained by sampling the single chip microcomputer, and Us is (inlet temperature, outlet temperature or back pressure) original data. For example, if the preset sensor curve Vout = (0.8 Dp + 10)/100; vout is the output signal, ranging from 0-5V, corresponding to a pressure measurement of 0-100 kPa; selecting 8 points according to the curve, and when Vout = 0.1, Dp = 0; that is, it is detected that the current sensor output is 0.1V and the pressure is 0.

It should be noted that the temperature normal flag, the first temperature abnormal flag, the second temperature abnormal flag, the back pressure normal flag, the back pressure abnormal flag, the bypass valve closed state flag, and the bypass valve open state flag are established, and a target value according to which determination is to be established: a temperature normal output target value, a temperature abnormal output target value, a back pressure normal output target value, a back pressure abnormal output target value and a bypass valve switch control target value;

the temperature normal output target value includes an inlet temperature threshold range, an outlet temperature threshold range, a transient stability time delay, and a detection result of whether the engine is operating, the temperature abnormal output target value includes an inlet temperature threshold range, an outlet temperature threshold range, a temperature stability time delay value, and a detection result of whether the engine is operating, the back pressure normal output target value includes a back pressure threshold range and a back pressure stability delay value, the back pressure abnormal output target value includes a back pressure threshold range and a back pressure stability delay value, and the bypass valve switch control target value includes a control bypass valve closing time, a control bypass valve opening time, and a bypass valve switching waiting time.

In one embodiment, the temperature monitoring module, when establishing the temperature normal flag, the first temperature abnormal flag, and the second temperature abnormal flag, executes:

sampling original data output by a temperature sensor, and calculating current values of inlet real-time temperature and outlet real-time temperature; after the stabilization time delay, comparing the time delay with target values (an inlet temperature threshold range and an outlet temperature threshold), and judging whether the tail gas treatment device operates abnormally; if the temperature is within the normal output target value range (within the inlet temperature threshold range and the outlet temperature threshold range), the temperature is normal during the operation of the engine, a temperature normal flag is established, and if the temperature is within the abnormal output target value range (outside the inlet temperature threshold range and the outlet temperature threshold range), the temperature is considered to be abnormal, and a first temperature abnormal flag or a second temperature abnormal flag is established.

In one embodiment, when the back pressure monitoring module establishes the back pressure normal flag and the back pressure abnormal flag, the back pressure monitoring module executes:

sampling original data output by a pressure sensor, and calculating the current value of real-time backpressure; after the stabilization time delay, comparing the time delay with a target value (backpressure threshold range) to judge whether the operation of the tail gas treatment device is abnormal; if the output pressure is within the range of the normal output target value (within the range of the backpressure threshold value), the pressure is normal when the engine is operated, and a backpressure normal mark is established.

In one embodiment, the bypass valve status monitoring module, when establishing the bypass valve closed status flag and the bypass valve open status flag, executes:

establishing second switching value input detection, sampling the current state of the bypass valve, and establishing a bypass valve closed state mark when a low level is obtained; and after the bypass valve closed state mark is established, detecting the effective level at a fixed interval of 50ms, if the effective high level is detected for one time within 1s, clearing the bypass valve closed state mark, waiting for the continuous acquisition of the high level state within 1s, and if the effective high level is acquired within 1s, considering that the current bypass valve is opened, and establishing a bypass valve opened state mark.

Because the number of applied field devices is large, the problem of interference is inevitably caused, when the low level is obtained, before the bypass valve closed state mark is established, the following steps are also executed: when the low level is acquired for the first time, the time is delayed by 50ms, the low level is acquired again, the effective low level is considered for the first time, and the bypass valve closed state mark is established again, so that the misjudgment interference is effectively removed.

In one embodiment, the engine condition monitoring module, when establishing the engine operating condition flag, performs:

establishing first switching value input detection, sampling the current state of the engine, and establishing an engine running state mark when a low level is obtained; and after the engine running state mark is established, detecting the effective level at a fixed interval of 50ms, if the effective high level is detected once within 1s, clearing the engine running state mark, waiting for continuously acquiring the high level state within 1s again, and if the effective high level is acquired within 1s, considering that the current engine is stopped and clearing the engine running state mark.

Furthermore, the monitoring and control system for the exhaust emission state of the engine further comprises a bypass valve response state confirmation module, which is used for starting timing when a bypass valve control signal is output; when the first time preset value is reached, the current state of the bypass valve is sampled again, and whether the current state of the bypass valve is consistent with the state of the bypass valve corresponding to the control signal of the bypass valve is judged; if the two signals are consistent, judging that the response of the bypass valve is successful, and enabling the engine controller to stop outputting a bypass valve control signal; otherwise, repeatedly executing the steps through a fixed time interval M1 until the output time of the bypass valve control signal is over; when the output time of the bypass valve control signal is over, if the current state of the bypass valve is judged to be inconsistent with the bypass valve state corresponding to the bypass valve control signal again, a bypass valve response failure alarm sign is established;

the bypass valve control signal comprises a first bypass valve opening command, a second bypass valve opening command, a third bypass valve opening command, a fourth bypass valve opening command and a bypass valve closing command.

In practical application, the bypass valve controls the signal output time, and the signal output time is set according to experience and can be adjusted adaptively.

It can be understood that when the control signal of the bypass valve is output, the current state signal of the bypass valve needs to be detected, and whether the bypass valve is successfully closed or opened is judged according to the type of the control signal and the current state of the bypass valve.

In one embodiment, the bypass valve response status confirmation module determines whether the bypass valve is successfully closed and successfully opened by:

after the bypass valve closing instruction is output, if the bypass valve is detected to be in a closing state, stopping outputting the bypass valve closing instruction, and judging that the bypass valve is successfully closed; when the bypass valve is detected to be in an open state, delaying 50ms of circular detection, and when the control signal output time is over, not detecting a bypass valve closing signal, establishing a bypass valve closing failure alarm sign;

after the bypass valve opening control signal is output, when the bypass valve opening state is detected, the control signal stops being output, and the bypass valve is successfully opened; and when the bypass valve is detected to be in a closed state, delaying 50ms for circular detection, and when the control signal output time is over, not detecting a bypass valve opening signal, and establishing a bypass valve opening failure alarm sign.

In particular, when the bypass valve opening failure alarm is effective, the controller does not output any control signal so as to avoid misoperation.

In particular, the bypass valve closure failure warning flag and the bypass valve opening failure warning flag need to be manually deactivated.

Example 3

The present embodiment provides a computer-readable storage medium having stored thereon a computer program which, when being executed by a processor, implements the steps of the method for monitoring and controlling the exhaust emission state of an engine as described above.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.

Those of ordinary skill in the art will appreciate that the various illustrative modules and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. 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 application.

In the embodiments provided in the present application, it should be understood that the disclosed system may be implemented in other ways. For example, the above-described system embodiments are merely illustrative, and for example, the division of the above-described modules is only one logical functional division, and other divisions may be realized in practice, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated module may be stored in a computer-readable storage medium if it is implemented in the form of a software functional unit and sold or used as a separate product. Based on such understanding, all or part of the flow in the method of the embodiments described above may be implemented by a computer program, which may be stored in a computer-readable storage medium and can implement the steps of the embodiments of the methods described above when the computer program is executed by a processor. The computer program includes computer program code, and the computer program code may be in a source code form, an object code form, an executable file or some intermediate form.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention and not to limit it; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will understand that: modifications to the specific embodiments of the invention or equivalent substitutions for parts of the technical features may be made; without departing from the spirit of the present invention, it is intended to cover all aspects of the invention as defined by the appended claims.

Claims (10)

1. A method for monitoring and controlling the exhaust emission state of an engine is characterized by comprising the following steps:

pre-configuring an inlet temperature threshold range, an outlet temperature threshold range and a backpressure threshold range of a pipeline of the tail gas treatment device;

calculating an inlet real-time temperature and an outlet real-time temperature of a tail gas treatment device pipeline, determining whether the inlet real-time temperature of the tail gas treatment device pipeline is within an inlet temperature threshold range and whether the outlet real-time temperature is within an outlet temperature threshold range, establishing a temperature normal mark when the inlet real-time temperature is within the inlet temperature threshold range and the outlet real-time temperature is within the outlet temperature threshold range, establishing a first temperature abnormal mark when the inlet real-time temperature is lower than the minimum value of the inlet temperature threshold range and the outlet real-time temperature is lower than the minimum value of the outlet temperature threshold range, and establishing a second temperature abnormal mark when the inlet real-time temperature is higher than the maximum value of the inlet temperature threshold range and the outlet real-time temperature is higher than the maximum value of the outlet temperature threshold range;

calculating the real-time backpressure pressure of the pipeline of the tail gas treatment device, and determining whether the real-time backpressure pressure of the pipeline of the tail gas treatment device is within a backpressure threshold range, if so, establishing a backpressure normal mark, otherwise, establishing a backpressure abnormal mark;

reading a current state signal of the engine, establishing an engine running state mark when the current state signal of the engine is at a low level, and clearing the engine running state mark if the current state signal of the engine is at the low level; reading a current state signal of the bypass valve, and establishing a closed state flag of the bypass valve when the current state signal of the bypass valve is at a low level, or else establishing an open state flag of the bypass valve;

when the engine running state mark is detected, whether the engine is in an idle starting stage is judged, and when the engine is in the idle starting stage:

generating a first bypass valve opening instruction in response to the obtained bypass valve closed state mark, the first temperature abnormal mark and the back pressure normal mark, and starting timing;

when the opening time set value corresponding to the first opening instruction of the bypass valve is reached, if a bypass valve opening state mark, a first temperature abnormal mark and a back pressure normal mark are obtained, a second opening instruction of the bypass valve is generated; the opening time set value corresponding to the second opening instruction of the bypass valve is larger than the opening time set value corresponding to the first opening instruction of the bypass valve;

when the engine running state mark is detected, whether the engine is in a high-speed running stage is also judged, and when the engine is in the high-speed running stage:

generating a bypass valve third opening instruction in response to the obtained bypass valve closed state mark, the temperature abnormal mark and the back pressure abnormal mark, and starting timing;

when the opening time set value corresponding to the bypass valve third opening instruction is reached, if a bypass valve opening state mark, a temperature abnormal mark and a back pressure abnormal mark are obtained, a bypass valve fourth opening instruction is generated; the opening time set value corresponding to the fourth opening command of the bypass valve is larger than the opening time set value corresponding to the third opening command of the bypass valve;

and when the engine is in an idle starting stage or a high-speed running stage, generating a bypass valve closing instruction in response to the obtained opening state mark of the bypass valve, the first temperature normal mark, the second temperature normal mark and the back pressure normal mark.

2. The engine exhaust emission state monitoring and control method according to claim 1, characterized in that: starting timing when the engine controller outputs a bypass valve control signal; when the first time preset value is reached, executing the following steps:

sampling the current state of the bypass valve again, and judging whether the current state of the bypass valve is consistent with the state of the bypass valve corresponding to the control signal of the bypass valve; if the two signals are consistent, judging that the response of the bypass valve is successful, and enabling the engine controller to stop outputting a bypass valve control signal; otherwise, repeatedly executing the steps through a fixed time interval M1 until the output time of the bypass valve control signal is over;

when the output time of the bypass valve control signal is over, if the current state of the bypass valve is judged to be inconsistent with the bypass valve state corresponding to the bypass valve control signal again, a bypass valve response failure alarm sign is established;

the bypass valve control signal comprises a first bypass valve opening command, a second bypass valve opening command, a third bypass valve opening command, a fourth bypass valve opening command and a bypass valve closing command.

3. The method for monitoring and controlling the exhaust emission state of an engine according to claim 2, wherein it is determined whether a bypass valve response failure alarm flag is read, the bypass valve response failure alarm flag including a bypass valve opening failure alarm flag and a bypass valve closing failure alarm flag;

in response to the read bypass valve opening failure alarm mark, the engine controller stops outputting a first bypass valve opening instruction, a second bypass valve opening instruction, a third bypass valve opening instruction and a fourth bypass valve opening instruction;

in response to reading the bypass valve closure failure warning flag, the engine controller stops outputting the bypass valve closure command.

4. The method for monitoring and controlling the exhaust emission state of an engine according to claim 1, wherein when calculating the inlet real-time temperature of the duct of the exhaust treatment device, performing:

acquiring inlet temperature original data of a pipeline of the tail gas treatment device based on a preset temperature sampling time interval, and sequentially placing the inlet temperature original data into a specified inlet temperature buffer area according to a time sequence;

counting the acquired original data volume of the inlet temperature, and when the original data volume of the inlet temperature is equal to a preset temperature sampling filter coefficient, calculating a first filter result D1 by using a pre-constructed inlet temperature filter model; selecting a corresponding calculation formula according to the type of the temperature sensor for acquiring the inlet real-time temperature, calculating an electric parameter corresponding to the first filtering result D1, and acquiring an inlet real-time temperature T1 based on the electric parameter and a preset sensor curve;

after the inlet real-time temperature T1 is obtained, timing is started;

and when new inlet temperature original data are acquired, deleting the first inlet temperature original data in the specified inlet temperature buffer area, placing a new inlet temperature signal in the specified inlet temperature buffer area, repeatedly executing the inlet real-time temperature calculation step, and updating the inlet real-time temperature until the temperature stabilization time delay is finished.

5. The method for monitoring and controlling the exhaust emission state of an engine according to claim 1, wherein when calculating the real-time back pressure of the pipeline of the exhaust treatment device, performing:

acquiring backpressure original data of a pipeline of the tail gas treatment device based on a preset pressure sampling time interval, and sequentially placing the backpressure original data into a specified backpressure buffer area according to a time sequence;

counting the acquired backpressure original data volume, when the backpressure original data volume is equal to a preset backpressure sampling filter coefficient, calculating a second filter result E1 by using a pre-constructed backpressure filter model, selecting a corresponding calculation formula according to the type of a pressure sensor for collecting backpressure, calculating an electric parameter corresponding to the second filter result E1, and obtaining real-time backpressure pressure F1 based on the electric parameter and a preset sensor curve;

after the real-time back pressure F1 is obtained, timing is started;

and when new backpressure original data are obtained, deleting the first backpressure original data in the specified backpressure buffer area, placing the new backpressure original data in the specified backpressure buffer area, repeatedly executing the real-time backpressure pressure calculation step, and updating the real-time backpressure pressure until the backpressure stabilization time delay is finished.

6. The engine exhaust emission state monitoring and control method according to claim 1, wherein when the engine operation state flag is established, the following is executed:

reading a first switching value detection result, if the first switching value detection result is an effective low level, judging that the engine is in a running state, establishing an engine running state mark, starting timing for S1 time period, and sequentially extracting the first switching value detection result at a fixed time interval N1;

if the first switching value detection result is detected to be an effective high level at least once when the timing of the S1 time period is ended, generating an instruction for clearing the engine running state flag, and starting the timing of the S2 time period;

and extracting the first switching value detection result in the time period of S2 until the time period of S2 is timed out, and if the first switching value detection result in the time period of S2 is all effective high level, judging that the engine is in a stop state, and executing the operation of clearing the engine running state flag.

7. The engine exhaust emission state monitoring and control method according to claim 1, characterized in that, when the bypass valve closed state flag or the bypass valve open state flag is established, the following is executed:

reading a second switching value detection result, if the second switching value detection result is an effective low level, judging that the bypass valve is in a closed state, establishing a bypass valve closed state mark, starting timing in S1 'time period, and sequentially extracting the second switching value detection result at a fixed time interval N1';

if the second switch quantity detection result is detected to be an effective high level at least once when the time period of S1 'is timed to end, generating a command of clearing the bypass valve closed state mark, and starting the time period of S2';

and extracting a second switching value detection result in the time period of S2 'until the time period of S2 is timed out, if the second switching value detection result in the time period of S2' is effective high level, judging that the bypass valve is in an open state, executing the operation of clearing the bypass valve closed state mark, and establishing the bypass valve open state mark.

8. A monitoring and control system for the exhaust emission state of an engine is characterized in that,

arranging a first temperature sensor for detecting the temperature of an inlet of a pipeline of the tail gas treatment device, a second temperature sensor for detecting the temperature of an outlet of the pipeline of the tail gas treatment device and a pressure sensor for detecting the back pressure of the pipeline of the tail gas treatment device; the first temperature sensor, the second temperature sensor and the pressure sensor are respectively connected with an engine controller, the engine controller is connected with a bypass valve in a control mode, and the bypass valve is configured to be in a closed state in advance;

the engine controller is provided with a temperature monitoring module, a backpressure monitoring module, an engine state monitoring module, a bypass valve state monitoring module and a valve control instruction generating module, and an inlet temperature threshold range, an outlet temperature threshold range and a backpressure threshold range of a tail gas treatment device pipeline are preconfigured;

the temperature monitoring module is used for calculating the inlet real-time temperature and the outlet real-time temperature of the pipeline of the tail gas treatment device, determining whether the inlet real-time temperature of the pipeline of the tail gas treatment device is within the inlet temperature threshold range and whether the outlet real-time temperature is within the outlet temperature threshold range, establishing a temperature normality flag when an inlet real-time temperature is within the inlet temperature threshold range and an outlet real-time temperature is within the outlet temperature threshold range, establishing a first temperature anomaly flag when an inlet real-time temperature is below a minimum of the inlet temperature threshold range and an outlet real-time temperature is below a minimum of the outlet temperature threshold range, establishing a second temperature anomaly flag when the inlet real-time temperature is greater than the maximum of the inlet temperature threshold range and the outlet real-time temperature is greater than the maximum of the outlet temperature threshold range;

the backpressure monitoring module is used for calculating the real-time backpressure of the pipeline of the tail gas treatment device and determining whether the real-time backpressure of the pipeline of the tail gas treatment device is within a backpressure threshold range, if so, establishing a backpressure normal mark, and otherwise, establishing a backpressure abnormal mark;

the engine state monitoring module is used for reading a current state signal of the engine, establishing an engine running state mark when the current state signal of the engine is at a low level, and clearing the engine running state mark if the current state signal of the engine is at the low level;

the bypass valve state monitoring module is used for reading a current state signal of the bypass valve, establishing a bypass valve closed state mark when the current state signal of the bypass valve is at a low level, and otherwise establishing a bypass valve open state mark;

the valve control instruction generation module is used for judging whether the engine is in an idle starting stage or not when the engine running state mark is detected, and when the engine is in the idle starting stage: generating a first bypass valve opening instruction in response to the obtained bypass valve closed state mark, the first temperature abnormal mark and the back pressure normal mark, and starting timing; when the opening time set value corresponding to the first opening instruction of the bypass valve is reached, if a bypass valve opening state mark, a first temperature abnormal mark and a back pressure normal mark are obtained, a second opening instruction of the bypass valve is generated;

the valve control instruction generation module is further used for judging whether the engine is in a high-speed operation stage or not when the engine operation state mark is detected, and when the engine is in the high-speed operation stage: generating a bypass valve third opening instruction in response to the obtained bypass valve closed state mark, the temperature abnormal mark and the back pressure abnormal mark, and starting timing; when the opening time set value corresponding to the bypass valve third opening instruction is reached, if a bypass valve opening state mark, a temperature abnormal mark and a back pressure abnormal mark are obtained, a bypass valve fourth opening instruction is generated;

the valve control instruction generating module is further used for responding to the obtained opening state mark of the bypass valve, the first temperature normal mark, the second temperature normal mark and the back pressure normal mark when the engine is in an idle starting stage or a high-speed running stage, and generating a bypass valve closing instruction.

9. The engine exhaust emission status monitoring and control system according to claim 8, further comprising a bypass valve response status confirmation module for initiating timing when a bypass valve control signal is output; when the first time preset value is reached, the current state of the bypass valve is sampled again, and whether the current state of the bypass valve is consistent with the state of the bypass valve corresponding to the control signal of the bypass valve is judged; if the two signals are consistent, judging that the response of the bypass valve is successful, and enabling the engine controller to stop outputting a bypass valve control signal; otherwise, repeatedly executing the steps through a fixed time interval M1 until the output time of the bypass valve control signal is over; when the output time of the bypass valve control signal is over, if the current state of the bypass valve is judged to be inconsistent with the bypass valve state corresponding to the bypass valve control signal again, a bypass valve response failure alarm sign is established;

the bypass valve control signal comprises a first bypass valve opening command, a second bypass valve opening command, a third bypass valve opening command, a fourth bypass valve opening command and a bypass valve closing command.

10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method for monitoring and controlling the exhaust emission status of an engine according to any one of claims 1 to 7.

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