CN113464259B

CN113464259B - Multi-stage type tail gas aftertreatment control method

Info

Publication number: CN113464259B
Application number: CN202110911220.XA
Authority: CN
Inventors: 夏长庚; 周鑫; 张丛丛; 窦晓; 刘厚斗; 肖进
Original assignee: China National Heavy Duty Truck Group Co ltd
Current assignee: China National Heavy Duty Truck Group Co ltd
Priority date: 2020-10-30
Filing date: 2020-10-30
Publication date: 2022-10-21
Anticipated expiration: 2040-10-30
Also published as: CN112360605A; CN113464259A; CN113586217A; CN112360605B; CN113586217B

Abstract

The invention discloses a multi-section type tail gas aftertreatment control method, which belongs to the technical field of engine exhaust gas aftertreatment and comprises the following steps: (1) Determining the number of post-treatment stages of a multi-stage tail gas post-treatment device connected to an exhaust system under a working condition; (2) Determining the access priority of each single-section post-processing unit; (3) Controlling the pipeline switching of the pipeline switching unit according to the determined section number and the access priority level of the single-section post-processing unit; (4) And re-determining the number of the post-treatment stages of the multi-stage tail gas post-treatment device connected to the exhaust system. The invention creatively designs the tail gas post-treatment into multi-stage treatment, so that the exhaust system can be selectively connected with the number of post-treatment stages, avoids connecting a redundant post-treatment mechanism, reduces the backpressure of the exhaust system of the engine, reduces the fuel consumption rate of the engine, improves the economy, and avoids the redundant post-treatment bearing heat load, thereby avoiding the unnecessary aging of the post-processor and reducing the aging speed of the post-treatment.

Description

Multi-stage type tail gas aftertreatment control method

The application is a divisional application of a patent application with the application number of 2020111913729 and the application date of 2020.10.30, and is entitled a multi-stage exhaust gas after-treatment device, a control device and a control method.

Technical Field

The invention relates to the technical field of after-treatment of tail gas discharged by an engine, in particular to a multi-section type tail gas after-treatment control method.

Background

The traditional engine aftertreatment is generally monolithic, namely a catalyst shell, a catalyst and the like are packaged into a big bag; generally, under most steady-state and transient working conditions of the vehicle engine during operation, the catalytic conversion efficiency of after-treatment is extremely high, and the treatment capacity of a catalyst for waste gas obviously overflows.

Under the working condition of high catalytic rate, the extra post-treatment except the catalytic amount is required, so that on one hand, the back pressure of the engine is increased, and the fuel consumption rate of the engine is increased; on the other hand, this portion of the excess aftertreatment catalyst is subjected to high temperature exhaust gas, which accelerates the aging of the aftertreatment.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a multi-section type tail gas aftertreatment control method; the multi-section type tail gas post-treatment control method is specially designed for the tail gas emission of the engine, the tail gas post-treatment mode is creatively designed into the multi-section type treatment mode, the exhaust system can be selectively connected with the number of post-treatment sections, the connection of a redundant post-treatment mechanism is avoided, the backpressure of the exhaust system of the engine is reduced, the fuel consumption rate of the engine is reduced, the economy is improved, the redundant post-treatment is prevented from bearing heat load, the unnecessary aging of a post-processor is avoided, and the aging speed of the post-treatment is reduced.

In order to solve the technical problems, the invention provides a multi-stage exhaust gas post-treatment device, which comprises an air inlet expansion pipe, wherein the air inlet expansion pipe is communicated with a single-stage post-treatment unit; the single-section post-processing unit comprises an inlet flange, the inlet flange is communicated with a pipeline switching unit, the pipeline switching unit is communicated with a double-layer pipeline, and the double-layer pipeline is communicated with an outlet flange; the single-section post-processing unit is at least provided with two sections.

In further improvement of the invention, the pipeline switching unit comprises a single-layer pipe valve body which is communicated with a double-layer pipe valve body, and the double-layer pipe valve body comprises an inner circular pipeline I and an outer circular pipeline I;

a double-piece semi-annular butterfly valve is arranged at the communication position of the single-layer pipe valve body and the double-layer pipe valve body, and a single-piece disc-shaped butterfly valve is arranged on the double-layer pipe valve body;

the double-piece semi-annular butterfly valve is used for connecting and disconnecting the single-layer pipe valve body and the outer annular pipeline I; the single disc-shaped butterfly valve is used for connecting and disconnecting the single-layer pipe valve body and the inner circular pipeline I.

Through the design, the scheme can be more convenient for selecting the path for the circulation of the waste gas; usually, the cross-sectional areas of the inner circular pipeline I and the outer circular pipeline I are consistent.

In the further improvement of the invention, the double-piece semi-ring butterfly valve comprises a semi-ring butterfly valve I and a semi-ring butterfly valve II;

the semi-annular butterfly valve I comprises an actuator I, the actuator I is connected with a valve rod I, the valve rod I extends into a communication position of the single-layer pipe valve body and the double-layer pipe valve body, and a semi-annular valve plate I is arranged on the valve rod I positioned at the pipe orifice of the outer annular pipeline I;

the semi-annular butterfly valve II comprises an actuator II, the actuator II is connected with a valve rod II, the valve rod II extends into a communication position of the single-layer pipe valve body and the double-layer pipe valve body, and a semi-annular valve plate II is arranged on the valve rod II positioned at the pipe orifice of the outer annular pipeline I;

the semi-annular valve plate I and the semi-annular valve plate II are symmetrically arranged;

and the rotation direction of the semi-annular valve plate I is opposite to that of the semi-annular valve plate II.

Through the design, the double-piece semi-annular butterfly valve can be switched on and off more conveniently, namely, the single-layer pipe valve body is connected with the outer annular pipeline I in a switching-on and switching-off mode; the design of the single-layer pipe valve body is convenient for the barrier-free rotation of the semi-annular valve plate I and the semi-annular valve plate II and is convenient for gas to flow between two layers of channels.

In the further improvement of the invention, the single-chip disk-shaped butterfly valve comprises an actuator III, wherein the actuator III is connected with a valve rod III, the valve rod III extends into an inner circular pipeline I, and a disk-shaped valve plate is arranged on the valve rod III positioned in the inner circular pipeline I.

Through the design, the single-disc butterfly valve can be switched on and off conveniently, namely, the single-layer pipe valve body and the inner circular pipeline I are communicated.

In a further improvement of the invention, the double-layer pipeline comprises an inner circular pipeline II and an outer circular pipeline II; and a catalytic unit is arranged in the inner circular pipeline II and is a three-effect catalyst or a particle trap.

Through the design, the scheme can be more convenient for treating waste gas.

In further improvement of the invention, an insulating layer is arranged on the outer wall of the inner circular pipeline II.

Through the design, the double-layer pipeline can be better protected by the scheme.

In the further improvement of the invention, the inner circular pipeline I is communicated with the inner circular pipeline II; and the outer annular pipeline I is communicated with the outer annular pipeline II.

Through the design, the scheme can facilitate the circulation of waste gas.

In a further improvement of the invention, the air inlet expansion pipe and the single-section post-processing unit, the single-section post-processing units and the single-section post-processing unit are connected with each other through flanges or hoops, and the single-section post-processing unit and the exhaust contraction pipe are connected with each other through hoops or hoops.

Through the design, the component can be more conveniently installed by the scheme.

A multi-section type tail gas aftertreatment control device comprises an access section number control module, an aftertreatment selection module, an aftertreatment aging analysis module and an abnormality detection module;

the access section number control module is used for determining the number of sections of the multi-section type tail gas post-processing device accessed to the exhaust pipeline according to the rotating speed and the air inlet pressure of the engine, through the pre-calibrated MAP based on the calibrated access pipeline number and the information sent by the abnormality detection module, and sending the obtained section number command to the post-processing selection module;

the post-processing aging analysis module is used for analyzing the aging condition of each section of single-section post-processing unit to obtain an aging grade sorting result and sending the aging grade sorting result to the post-processing selection module;

the post-processing selection module controls the pipeline switching of the pipeline switching unit according to the information sent by the access segment number control module and the post-processing aging analysis module;

and the abnormality detection module is used for detecting the working condition and the post-processing state of the engine and sending the abnormal information to the access section number control module.

Through the design, the scheme can more conveniently finish the selection of post-treatment.

A multi-section type tail gas aftertreatment control method comprises the following steps:

(1) According to the rotating speed and the air inlet pressure of the engine, the number of aftertreatment stages of the multi-stage tail gas aftertreatment device connected into an exhaust system under the working condition is determined through the pre-calibrated access pipeline quantity MAP based on calibration and the detected abnormal information of the working condition or the aftertreatment state parameters of the engine;

(2) The aging condition of each single-section post-processing unit is analyzed by recording the time length of each single-section post-processing unit accessing the exhaust system, the access priority of each single-section post-processing unit is determined based on the condition of each single-section post-processing unit, and the single-section post-processing unit with low aging degree is preferentially accessed to the exhaust system, so that the aging degree of each single-section post-processing unit is ensured to be close;

(3) Controlling the pipeline switching of the pipeline switching unit according to the determined section number and the access priority level of the single-section post-processing unit;

(4) And detecting the working condition and the post-treatment state of the engine, and when the working condition of the engine suddenly changes or the parameters of the post-treatment state are abnormal, re-determining the number of post-treatment stages of the multi-stage tail gas post-treatment device connected to the exhaust system.

Compared with the prior art, the invention has the following beneficial effects:

the invention is specially designed for the exhaust emission of the engine, and creatively designs the exhaust post-treatment mode into a multi-section treatment mode, so that the exhaust system can be selectively connected with the number of post-treatment sections, an excessive post-treatment mechanism is avoided, the backpressure of the exhaust system of the engine is reduced, the fuel consumption rate of the engine is reduced, the economy is improved, and the excessive post-treatment is prevented from bearing heat load, thereby avoiding the unnecessary aging of a post-processor and reducing the aging speed of the post-treatment.

Drawings

To more clearly illustrate the background art or the technical solutions of the present invention, the following brief description of the drawings incorporated in the prior art or the detailed description of the present invention; it should be understood that the structures, proportions, and dimensions shown in the drawings and described herein are for illustrative purposes only and are not intended to limit the scope of the present invention, which is to be given the full breadth of the present disclosure, and are not intended to limit the scope of the present disclosure.

FIG. 1 is a schematic structural diagram of an embodiment of the present invention.

Fig. 2 is an exploded schematic view of the present invention.

Fig. 3 is a schematic structural diagram of a pipeline switching unit according to the present invention.

Fig. 4 is a schematic diagram of the switching principle of the pipeline switching unit of the present invention 1.

Fig. 5 is a schematic diagram of the switching principle of the pipeline switching unit of the present invention 2.

Fig. 6 is a schematic diagram of the switching principle of the pipeline switching unit of the present invention 3.

Fig. 7 is a schematic diagram 3 illustrating the switching principle of the pipeline switching unit according to the present invention.

FIG. 8 is a schematic diagram of a module structure according to the present invention.

FIG. 9 is a flow chart of the method of the present invention.

Shown in the figure: 1-an air inlet expanding pipe; 2-a pipeline switching unit; 3-double layer pipeline; 4-exhaust shrinkage pipe; 5-single layer tube valve body; 6-an inner circular pipeline I; 7-an outer annular duct i; 8-actuator I; 9-a semi-annular valve plate I; 10-an actuator II; 11-a semi-annular valve plate II; 12-actuator III; 13-a disc valve plate; 14-an inner circular pipeline II; 15-outer annular duct ii.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the following will make clear and complete description of the technical solution in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by those skilled in the art without creative efforts based on the embodiments of the present invention shall fall within the protection scope of the present invention.

Meanwhile, the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like referred to in the present specification indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, it is not to be understood that the present invention is limited to changes or adjustments of relative relationships thereof, and also to be considered as a scope in which the present invention can be implemented without substantial technical changes.

Meanwhile, in the description of the present specification, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "connected", and "connected" are to be interpreted broadly, and may be, for example, a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, and the two components can be communicated with each other, so that the specific meaning of the terms in the invention can be understood by those skilled in the art through specific situations.

As shown in fig. 1 and 2, a multi-stage exhaust gas post-treatment device comprises an air inlet expansion pipe 1, wherein the air inlet expansion pipe 1 is communicated with a single-stage post-treatment unit, and the single-stage post-treatment unit is communicated with an exhaust contraction pipe 4; the single-section post-processing unit comprises an inlet flange, the inlet flange is communicated with a pipeline switching unit 2, the pipeline switching unit 2 is communicated with a double-layer pipeline 3, and the double-layer pipeline 3 is communicated with an outlet flange; the single-section post-processing unit is at least provided with two sections.

As shown in fig. 3-7, the pipeline switching unit 2 includes a single-layer pipe valve body 5, the single-layer pipe valve body 5 is communicated with a double-layer pipe valve body, and the double-layer pipe valve body includes an inner circular pipeline i 6 and an outer circular pipeline i 7; a double-piece semi-annular butterfly valve is arranged at the communication position of the single-layer pipe valve body 5 and the double-layer pipe valve body, and a single-piece disc-shaped butterfly valve is arranged on the double-layer pipe valve body; the double-piece semi-annular butterfly valve is used for connecting and disconnecting the single-layer pipe valve body 5 and the outer annular pipeline I6; the single disc butterfly valve is used for connecting and disconnecting the single-layer pipe valve body 5 and the inner circular pipeline I7.

The double-piece semi-annular butterfly valve comprises a semi-annular butterfly valve I and a semi-annular butterfly valve II; the semi-annular butterfly valve I comprises an actuator I8, the actuator I8 is connected with a valve rod I, the valve rod I extends into a communication position of the single-layer pipe valve body 5 and the double-layer pipe valve body, and a semi-annular valve plate I9 is arranged on the valve rod I at the pipe orifice of the outer annular pipeline I7; the semi-annular butterfly valve II comprises an actuator II 10, the actuator II 10 is connected with a valve rod II, the valve rod II extends into a communication position of the single-layer pipe valve body 5 and the double-layer pipe valve body, and a semi-annular valve plate II 11 is arranged on the valve rod II positioned at the pipe orifice of the outer annular pipeline I7; the semi-annular valve plate I10 and the semi-annular valve plate II 11 are symmetrically arranged; and the rotation direction of the semi-annular valve plate I10 is opposite to that of the semi-annular valve plate II 11.

The single-chip disc-shaped butterfly valve comprises an actuator III 12, the actuator III 12 is connected with a valve rod III, the valve rod III extends into the inner circular pipeline I, and a disc-shaped valve plate 13 is arranged on the valve rod III located in the inner circular pipeline I.

The double-layer pipeline 3 comprises an inner circular pipeline II 14 and an outer circular pipeline II 15; and a catalytic unit is arranged in the inner circular pipeline II 14 and is a three-effect catalyst or a particle trap.

And an insulating layer is arranged on the outer wall of the inner circular pipeline II 14.

The inner circular pipeline I7 is communicated with the inner circular pipeline II 14; the outer annular pipeline I7 is communicated with an outer annular pipeline II 15.

And the air inlet expansion pipe 1 and the single-section post-processing unit, the single-section post-processing units, the single-section post-processing unit and the exhaust contraction pipe 4 are connected by flanges or hoops.

As shown in fig. 8, a multi-stage exhaust gas post-treatment control device includes an access stage number control module, a post-treatment selection module, a post-treatment aging analysis module, and an abnormality detection module;

As shown in fig. 9, a multi-stage exhaust aftertreatment control method includes the following steps:

(1) According to the rotating speed and the air inlet pressure of the engine, determining the number of aftertreatment stages of the multi-stage exhaust aftertreatment device connected into an exhaust system under the working condition through pre-calibrated access pipeline quantity MAP based on calibration and detected abnormal information of the working condition or aftertreatment state parameters of the engine;

( Receiving real-time engine rotating speed and air inlet pressure signals sent by an ECU (electronic control Unit) and correction signals sent by an abnormality detection module, and comprehensively determining the number of aftertreatment stages of the working condition accessed to an exhaust system based on the calibrated access pipeline number MAP; the access pipeline quantity MAP is obtained by integrating the original engine emission MAP of the engine and the post-treatment emission reduction rate MAP responding to the working condition, and the MAP is a short name of a universal characteristic curve chart )

(4) Detecting the working condition and the post-treatment state of the engine, and re-determining the number of post-treatment stages of the multi-stage tail gas post-treatment device connected to the exhaust system when the working condition of the engine suddenly changes or the parameters of the post-treatment state are abnormal;

(receiving signals of various sensors of ECU and post-processing, when the change of the rotating speed or the intake pressure of the engine exceeds a set threshold value, or detecting the abnormality of parameters of the post-processing state, such as oxygen storage amount of TWC, carbon loading amount of DPF and other parameters, calculating the quantity correction quantity of the access pipelines, feeding the quantity correction quantity back to the access section quantity control module, and re-determining the quantity of the post-processing access systems by the access section quantity control module).

The application aims at solving the problems that the surplus of the catalytic capacity of the post-treatment overflows under the condition that the working condition of the engine is stable or the emission is low, the utilization rate of the post-treatment is low, the redundant post-treatment catalyst bears high temperature, the post-treatment is accelerated and aged, and the backpressure of the engine is additionally increased.

According to the running state of the engine, all post-treatments are connected into the pipeline when the emission or the conversion efficiency is high, and only part of the post-treatments are selected to be connected into the pipeline based on the state of each section of post-treatment when the emission or the conversion efficiency is low, so that the reduction of back pressure is realized, and the aging of redundant post-treatments is avoided.

Compared with the prior art, the invention has the following advantages:

(1) By flexibly switching the number of the post-treatments connected to the exhaust pipeline, the conversion efficiency which is the same as that of the original post-treatment can be kept when the emission efficiency is high or low, and the backpressure of an engine exhaust system is reduced and the economy is improved when the emission efficiency is low or high;

(2) When the catalytic capacity of the post-treatment is surplus, the redundant post-treatment is moved out of the exhaust pipeline, so that the post-treatment can be prevented from bearing heat load, unnecessary aging of the post-treatment device is avoided, and the aging speed of the post-treatment is reduced;

(3) The aging degree of the multi-section post-treatment can be kept consistent by flexibly switching the post-treatment positions of the access pipelines and alternately taking part in catalysis, the overall efficiency of the post-treatment can be improved in the whole life cycle by balancing the aging of each section of post-treatment, the service life is prolonged, and the post-treatment economy is improved;

(4) The multi-section structure can enhance the turbulence of waste gas, promote the contact of airflow and active substances, and improve the post-treatment performance to a certain extent.

The present application discloses a multi-stage post-processing structure

As shown in fig. 1, the multi-stage post-treatment comprises an inlet expanding pipe, a plurality of single-stage post-treatment units (taking 3 units as an example), and an exhaust contracting pipe which are connected in series; between expansion pipe and the single section aftertreatment unit admits air, the single section aftertreatment unit is each other to and between single section aftertreatment unit and the exhaust shrink tube, be connected with flange or clamp, guarantee the gas tightness.

Wherein, when the waste gas passes through the outer annular pipeline II, the waste gas does not pass through a post-treatment catalyst; the inner circular pipeline II contains a post-treatment catalyst and a carrier, and when waste gas passes through the inner circular pipeline II, the waste gas in the exhaust gas can be treated; a heat-insulating layer can be designed between the inner circular pipeline II and the outer circular pipeline II, so that the problem that the post-treatment temperature of the inner circular pipeline II is too high when the inner circular pipeline II is communicated with waste gas or the post-treatment temperature of the inner circular pipeline II is too high when the outer circular pipeline II is communicated with the waste gas is avoided; the pipeline through which the waste gas passes is mainly controlled by a pipeline switching unit according to the working condition of the engine and the conditions of various parameters of post-treatment.

This application pipeline switching mechanism

The pipeline switching unit controls the on-off of the inner and outer pipelines (the on-off of the single-layer pipe valve body and the outer annular pipeline I, and the on-off of the single-layer pipe valve body and the inner circular pipeline I). According to the working condition of the engine, the post-processing parameters and the like, the controller can determine the pipeline opened by each section of post-processing unit according to a pipeline switching control strategy. When the communication between the single-layer pipe valve body and the outer annular pipeline I is selected, the double-piece semi-annular butterfly valve is opened, the single-piece disc-shaped butterfly valve is closed, and vice versa.

Pipeline switching control strategy

The pipeline switching control strategy mainly comprises an access section number control module, a post-processing selection module, a post-processing aging analysis module and an abnormity detection module.

And comprehensively determining the number of the post-processing stages of the working condition accessed to the exhaust system according to the rotating speed and the air inlet pressure of the engine, the pre-calibrated MAP based on the calibrated access pipeline number and the corrected value output by the abnormality detection module.

If the post-processing is not completely accessed, if one section or two sections are accessed, the post-processing selection module is used for controlling which post-processing access pipelines; and then, switching the corresponding post-processing pipeline state to a required state by using a pipeline switching mechanism.

And the post-processing aging analysis module analyzes the aging condition of each section of post-processing by recording the time length of each section of post-processing accessing the exhaust system, and feeds back the aging condition to the post-processing selection module based on the condition of each section of post-processing to influence the priority of post-processing selection, wherein if the post-processing with low aging degree is selected, the priority is higher so as to ensure that the aging degree of each section of post-processing is close.

And the abnormity detection module is mainly responsible for feeding back to the access section number control module when sudden change of the working condition of the engine or abnormal post-treatment state parameters such as oxygen storage amount of TWC (diesel particulate filter), carbon loading amount of DPF (diesel particulate filter) and the like are detected to be obviously abnormal, re-determining the number of post-treatment access systems and ensuring that the post-treatment systems have optimal conversion efficiency under the abnormal condition.

Although the present invention has been described in detail with reference to the preferred embodiments, the present invention is not limited thereto, and those skilled in the art can make various equivalent modifications or substitutions on the embodiments of the present invention without departing from the spirit and essence of the present invention, and those modifications or substitutions should be considered as being within the scope of the present invention/any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present disclosure, and therefore, the scope of the present invention should be determined by the scope of the claims.

Claims

1. A multi-section type tail gas aftertreatment control method is characterized by comprising the following steps: the method comprises the following steps:

(1) According to the rotating speed and the air inlet pressure of the engine, determining the number of post-treatment stages of the multi-stage tail gas post-treatment device connected to the exhaust system under the working condition based on the calibrated access pipeline number MAP and the detected abnormal information of the working condition and the post-treatment state parameters of the engine, wherein the access pipeline number MAP is comprehensively obtained according to the original engine emission MAP of the engine and the post-treatment emission reduction rate MAP responding to the working condition;

(2) The aging condition of each single-section post-processing unit is analyzed by recording the time length of each single-section post-processing unit accessing the exhaust system, the access priority of each single-section post-processing unit is determined based on the aging condition of each single-section post-processing unit, and the single-section post-processing unit with low aging degree is preferentially accessed to the exhaust system, so that the aging degree of each single-section post-processing unit is ensured to be close;