CN110985169B

CN110985169B - Control method and device of post-processing system and post-processing system

Info

Publication number: CN110985169B
Application number: CN201911257496.XA
Authority: CN
Inventors: 吕志华; 王晓华; 王意宝; 王作峰; 孙婷
Original assignee: Weichai Power Co Ltd
Current assignee: Weichai Power Co Ltd
Priority date: 2019-12-10
Filing date: 2019-12-10
Publication date: 2021-02-23
Anticipated expiration: 2039-12-10
Also published as: CN110985169A

Abstract

The embodiment of the application provides a control method and device of an aftertreatment system and the aftertreatment system, wherein an upstream temperature parameter of a first selective catalytic reduction device and an upstream temperature parameter of a second selective catalytic reduction device in the aftertreatment system are detected, and the second selective catalytic reduction device is located at the downstream of the first selective catalytic reduction device. And if the upstream temperature parameter of the first selective catalytic reduction device is detected to be lower than the start-up temperature of the injection system, starting the electric heating catalyst to heat the reduction catalyst of the first selective catalytic reduction device. And optimizing and regulating a strategy for injecting the reducing agent by a nozzle in the injection system according to the upstream temperature parameter of the first selective catalytic reduction device and the upstream temperature parameter of the second selective catalytic reduction device.

Description

Control method and device of post-processing system and post-processing system

Technical Field

The application relates to the technical field of automobile emission, in particular to a control method and device of an aftertreatment system and the aftertreatment system.

Background

With the rapid development of the automobile industry in China, the number of automobiles in China is continuously increased, meanwhile, the air pollution caused by automobile emission is more and more serious, and for the reason, the upgrading speed of the automobile emission regulation is slowly accelerated, and the current emission standard is updated to the six national standards. In order to adapt to the development of society and meet the national emission standard, the emission of harmful substances in the exhaust gas of automobile engines must be reduced as much as possible.

In the prior art, exhaust of an automobile engine is generally treated by an after-treatment system, so that the emission of harmful substances in the exhaust of the automobile engine is reduced. However, the existing engine aftertreatment system is not tightly coupled with the engine exhaust, and mostly adopts an arrangement mode of an oxidation type catalyst, a particle catcher and a selective catalytic reduction device, and because the working temperature required by the selective catalytic reduction device is higher, the working temperature of the selective catalytic reduction device cannot be reached when the engine is in cold start at low temperature, the treatment of NOx (nitrogen oxide) is incomplete, and the emission requirement cannot be met.

Disclosure of Invention

In view of this, embodiments of the present application provide a control method and apparatus for an aftertreatment system, and the aftertreatment system, which use an electrically heated catalyst to rapidly raise the temperature of the aftertreatment system and a better strategy for regulating and controlling an injection system, thereby improving the conversion efficiency of nitrogen oxides in engine exhaust and the regeneration efficiency of a particle trap, and reducing the emission of harmful substances in engine exhaust.

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

the first aspect of the present application discloses a control method for an aftertreatment system, including:

detecting a first temperature parameter and a second temperature parameter in the aftertreatment system; wherein the first temperature parameter is an upstream temperature parameter of a first selective catalytic reduction device and the second temperature parameter is an upstream temperature parameter of a second selective catalytic reduction device; the second selective catalytic reduction device is located downstream of the first selective catalytic reduction device;

if the first temperature parameter is detected to be lower than a preset first temperature threshold value, starting the electric heating catalytic converter; wherein the first temperature threshold is the start-up temperature of the injection system; the electric heating catalyst is used for heating the reduction catalyst of the first selective catalytic reduction device;

and regulating whether a nozzle in the injection system injects the reducing agent or not according to the first temperature parameter and the second temperature parameter.

Optionally, in the method, after the detecting that the first temperature parameter is lower than the preset first temperature threshold, starting the electrically heated catalyst, the method further includes:

in the starting process of the electric heating catalytic converter, if the detected first temperature parameter reaches the first temperature threshold value, the electric heating catalytic converter is closed.

Optionally, in the method, the controlling whether a nozzle in the injection system injects the reducing agent according to the first temperature parameter and the second temperature parameter includes:

if the first temperature parameter and the second temperature parameter are both less than the first temperature threshold, closing a first nozzle and a second nozzle in the injection system; wherein the first nozzle is used for injecting the reducing agent to an upstream pipeline of a first selective catalytic reduction device, and the second nozzle is used for injecting the reducing agent to an upstream pipeline of a second selective catalytic reduction device;

if the first temperature parameter is greater than the first temperature threshold and the second temperature parameter is less than a preset first temperature threshold, starting the first nozzle and closing the second nozzle;

if the first temperature parameter and the second temperature parameter are both greater than the first temperature threshold and the second temperature parameter is less than a second temperature threshold, simultaneously starting the first nozzle and the second nozzle; the second temperature threshold is the temperature for efficient conversion of nitrogen oxides, and is greater than the first temperature threshold;

and if the first temperature parameter is greater than the first temperature threshold and the second temperature parameter is greater than the second temperature threshold, starting the second nozzle and closing the first nozzle.

Optionally, the method further includes:

detecting a pressure differential parameter of a particle trap during operation of the aftertreatment system;

if the pressure difference parameter reaches a preset first pressure difference threshold value, starting the electric heating catalytic converter and closing an exhaust valve; wherein the preset first pressure differential threshold is a threshold at which the particle trap reaches passive regeneration;

in the starting process of the electric heating catalyst, if the detected pressure difference parameter of the particle catcher is lower than a preset second pressure difference threshold value, the electric heating catalyst is closed; wherein the preset second pressure difference threshold is smaller than the preset first pressure difference threshold.

Optionally, the method further includes:

if the pressure difference parameter reaches a preset third pressure difference threshold value, starting the electric heating catalytic converter, and starting the injection system to inject fuel or controlling the engine to inject fuel after the engine is in a cylinder; wherein the preset third pressure differential threshold is a threshold at which the particle trap reaches active regeneration.

A second aspect of the present application discloses a control device of an aftertreatment system, including:

the detection unit is used for detecting a first temperature parameter and a second temperature parameter in the post-processing system; wherein the first temperature parameter is an upstream temperature parameter of a first selective catalytic reduction device and the second temperature parameter is an upstream temperature parameter of a second selective catalytic reduction device; the second selective catalytic reduction device is located downstream of the first selective catalytic reduction device;

the starting unit is used for starting the electric heating catalytic converter if the detection unit detects that the first temperature parameter is lower than a preset first temperature threshold value; wherein the first temperature threshold is the start-up temperature of the injection system;

and the regulating and controlling unit is used for regulating and controlling whether a nozzle in the injection system injects the reducing agent or not according to the first temperature parameter and the second temperature parameter.

Optionally, the above apparatus further includes:

and the first detection subunit is used for closing the electric heating catalytic converter if the detected first temperature parameter reaches the first temperature threshold value in the starting process of the electric heating catalytic converter.

Optionally, in the above apparatus, the control unit includes:

a first regulating and controlling subunit, configured to close a first nozzle and a second nozzle in the injection system if the first temperature parameter and the second temperature parameter are both smaller than the first temperature threshold; wherein the first nozzle is used for injecting the reducing agent to an upstream pipeline of a first selective catalytic reduction device, and the second nozzle is used for injecting the reducing agent to an upstream pipeline of a second selective catalytic reduction device;

the second regulating and controlling subunit is used for starting the first nozzle and closing the second nozzle if the first temperature parameter is greater than the first temperature threshold and the second temperature parameter is less than a preset first temperature threshold;

a third control subunit, configured to start the first nozzle and the second nozzle simultaneously if the first temperature parameter and the second temperature parameter are both greater than the first temperature threshold and the second temperature parameter is less than a second temperature threshold; the second temperature threshold is the temperature for efficient conversion of nitrogen oxides, and is greater than the first temperature threshold;

and the fourth regulating and controlling subunit is used for starting the second nozzle and closing the first nozzle if the first temperature parameter is greater than the first temperature threshold and the second temperature parameter is greater than the second temperature threshold.

Optionally, the above apparatus further includes:

a second detection subunit for detecting a pressure differential parameter of the particle trap during operation of the aftertreatment system;

the fifth regulating and controlling subunit is used for starting the electric heating catalytic converter and closing the exhaust valve if the pressure difference parameter reaches a preset first pressure difference threshold value; wherein the preset first pressure differential threshold is a threshold at which the particle trap reaches passive regeneration;

the third detection subunit is used for closing the electrically heated catalyst in the starting process of the electrically heated catalyst if the detected pressure difference parameter of the particle catcher is lower than a preset second pressure difference threshold value; wherein the preset second pressure difference threshold is smaller than the preset first pressure difference threshold.

Optionally, the above apparatus further includes:

the fourth detection subunit is used for detecting the pressure difference parameter of the particle catcher in the operation process of the post-processing system;

the sixth regulating and controlling subunit is used for starting the electric heating catalytic converter and starting an injection system to inject fuel or controlling an engine to inject fuel after a cylinder if the differential pressure parameter reaches a preset third differential pressure threshold value; wherein the preset third pressure differential threshold is a threshold at which the particle trap reaches active regeneration.

A third aspect of the present application discloses an aftertreatment system, comprising:

an electronic control unit for performing the method of any one of the first aspects of the present application;

a first temperature sensor and a second temperature sensor; the first temperature sensor is used for detecting and obtaining the first temperature parameter; the second temperature sensor is used for detecting to obtain the second temperature parameter;

an electrically heated catalyst, a first selective catalytic reduction device, an oxidation catalyst, a particle trap, and a second selective catalytic reduction device; the second selective catalytic reduction device is located downstream of the first selective catalytic reduction device;

an injection system; wherein the injection system comprises: a first nozzle, and a first spray control system for controlling the first nozzle, a second nozzle, and a second spray control system for controlling the second nozzle; the first nozzle is used for injecting reducing agent to an upstream pipeline of the first selective catalytic reduction device, and the second nozzle is used for injecting reducing agent to an upstream pipeline of the second selective catalytic reduction device.

Optionally, in the system described above, the electrically heated catalyst and the first selective catalytic reduction device are collectively configured to: an electrically heated catalyst having a surface coated with a reduction catalyst.

Optionally, in the above system, the second selective catalytic reduction device includes: the second selective catalytic reduction device is an integrated device with the ammonia gas processor.

Optionally, in the above system, the particle trap comprises: a particle trap coated with a reduction catalyst.

According to the technical scheme, the control method of the aftertreatment system provided by the application detects the upstream temperature parameter of the first selective catalytic reduction device and the upstream temperature parameter of the second selective catalytic reduction device in the aftertreatment system, wherein the second selective catalytic reduction device is located at the downstream of the first selective catalytic reduction device. And if the upstream temperature parameter of the first selective catalytic reduction device is detected to be lower than the start-up temperature of the injection system, starting the electric heating catalyst to heat the reduction catalyst of the first selective catalytic reduction device. And optimizing and regulating a strategy for injecting the reducing agent by a nozzle in the injection system according to the upstream temperature parameter of the first selective catalytic reduction device and the upstream temperature parameter of the second selective catalytic reduction device. Therefore, the temperature of the aftertreatment system is quickly raised through the electric heating catalyst, and the strategy of regulating and controlling the injection system is better, so that the conversion efficiency of nitrogen oxides in the engine tail gas and the regeneration efficiency of the particle catcher are improved, and the emission of harmful substances in the engine tail gas is reduced.

Drawings

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

FIG. 1 is a schematic illustration of an aftertreatment system disclosed in an embodiment of the present application;

FIG. 2 is a schematic view of another aftertreatment system disclosed in an embodiment of the present application;

FIG. 3 is a schematic view of another aftertreatment system disclosed in an embodiment of the present application;

FIG. 4 is a schematic view of another aftertreatment system disclosed in an embodiment of the present application;

FIG. 5 is a flow chart of a method of controlling an aftertreatment system according to an embodiment of the disclosure;

fig. 6 is a schematic diagram of a control device of an aftertreatment system according to an embodiment of the disclosure.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In this application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Moreover, in this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

As can be seen from the background art, in the prior art, exhaust gas of an automobile engine is generally treated by an after-treatment system, so as to reduce the emission of harmful substances in the exhaust gas of the automobile engine. However, the existing engine aftertreatment system is not tightly coupled with the engine exhaust, and mostly adopts an arrangement mode of an oxidation type catalyst, a particle catcher and a selective catalytic reduction device, and because the working temperature required by the selective catalytic reduction device is higher, the working temperature of the selective catalytic reduction device cannot be reached when the engine is in cold start at low temperature, the treatment of NOx (nitrogen oxide) is incomplete, and the emission requirement cannot be met.

Based on this, the embodiment of the application provides a control method and device for an aftertreatment system and the aftertreatment system, and the temperature of the aftertreatment system is rapidly raised through an electrically heated catalyst, and a better strategy for regulating and controlling an injection system is adopted, so that the conversion efficiency of nitrogen oxides in engine exhaust and the regeneration efficiency of a particle trap are improved, and the emission of harmful substances in the engine exhaust is reduced.

An embodiment of the present application provides an aftertreatment system, as shown in fig. 1, specifically including:

an electronic control unit (not shown).

It should be noted that the Electronic Control Unit (Electronic Control Unit) may also be called a driving computer, and like a general computer, the Electronic Control Unit is composed of a Microprocessor (MCU), a memory (ROM, RAM), an input/output interface (I/O), an analog-to-digital converter (a/D), and a large-scale integrated circuit such as a shaping circuit and a driving circuit. The post-processing system is integrally regulated and controlled by the electronic control unit, and the control method of the post-processing system provided by the embodiment of the application is executed.

A first temperature sensor 101 and a second temperature sensor 102; the first temperature sensor 101 is used for detecting and obtaining a first temperature parameter; the second temperature sensor 102 is used for detecting a second temperature parameter. Specifically, the first temperature sensor is disposed in an upstream pipe of the first Selective Catalytic Reduction (SCR) device 103, and is configured to detect an upstream temperature parameter of the first SCR device 103, that is, a first temperature parameter; the second temperature sensor is disposed in an upstream pipe of the second selective catalytic reduction device 104, and is configured to detect an upstream temperature parameter of the second selective catalytic reduction device 104, that is, a second temperature parameter.

An Electrically Heated Catalyst (EHC) 105, a first selective catalytic reduction device 103, an oxidation Catalyst (DOC) 106, a Particulate trap (DPF) 107, and a second selective catalytic reduction device 104; the second selective catalytic reduction device 104 is located downstream of the first selective catalytic reduction device 103.

Note that the electrically heated catalyst 105 is disposed upstream of the first selective catalytic reduction device and is connected to the engine 113. The oxidation catalyst 106, the particle trap 107, the second selective catalytic reduction device 104, and the ammonia gas processor 114 are connected to a downstream portion of the first selective catalytic reduction device 103.

When the first temperature sensor 101 detects that the upstream temperature parameter of the first selective catalytic reduction device 103 is lower than the start-up temperature (generally 180 ℃) of the injection system, for example, the temperature is often lower during cold start of the engine, the electrically heated catalyst 105 starts the heating function, so that the reduction catalyst in the first selective catalytic reduction device quickly reaches the optimal catalytic temperature, and meanwhile, the temperature of other components in the aftertreatment system can also be raised. Furthermore, the electrically heated catalyst 105 is also used for the passive regeneration and the active regeneration of the particle trap 107, and the temperature of the particle trap 107 can reach the temperature required for the passive regeneration and the active regeneration more quickly by using the electrically heated catalyst 105.

The first selective catalytic reduction device 103 and the second selective catalytic reduction device 104 may reduce the emission of NOx by chemically reacting with NOx using a catalyst to convert NOx into N2 (nitrogen gas) and H2O (water).

The oxidation catalyst 106 can reduce HC (hydrocarbon) emissions, oxidize NO (nitrogen monoxide) to NO2 (nitrogen dioxide), and oxidize fuel injected into the exhaust pipe.

The particle trap 107 can trap particulate matter, mainly soot, in the engine exhaust. The particle trap 107 may be provided with a differential pressure sensor 108 for detecting a differential pressure parameter in the particle trap 107 to reflect a carbon deposit value, thereby determining whether to perform passive regeneration or active regeneration of the particle trap 107.

Optionally, in another embodiment of the present application, another implementation of the particle trap 107 includes: a particle trap coated with a reducing catalyst, also known as SCRF.

By coating the surface of the particle trap with the reduction catalyst, the particle trap which originally can only trap particulate matters in the engine exhaust can simultaneously convert the NOx by using the reducing agent injected by the injection system, so that the NOx conversion efficiency is improved.

An injection system; wherein the injection system comprises: a first nozzle 109, and a first spray control system 110 for controlling the first nozzle 109, a second nozzle 111, and a second spray control system 112 for controlling the second nozzle 111; the first nozzle 109 is used to inject the reducing agent into the upstream pipe of the first selective catalytic reduction device 103, and the second nozzle 111 is used to inject the reducing agent into the upstream pipe of the second selective catalytic reduction device 104.

It should be noted that the first nozzle 109 is disposed in the upstream pipe of the first selective catalytic reduction device 103, and when the first temperature sensor 101 detects that the upstream pipe temperature parameter of the first selective catalytic reduction device 103 reaches the start-injection temperature of the injection system, the electronic control unit regulates the first injection control system 110 to control the first nozzle 109 to inject the reducing agent, which may be liquid urea or gaseous NH3 (ammonia gas), into the upstream pipe of the first selective catalytic reduction device 103, so as to cause the first selective catalytic reduction device 103 to convert NOx through the catalyst. The second nozzle 111 is disposed in the upstream pipe of the second selective catalytic reduction device 104, and when the second temperature sensor 102 detects that the upstream pipe temperature parameter of the second selective catalytic reduction device 104 reaches the start-injection temperature of the injection system, the electronic control unit regulates the second injection control system 112 to control the second nozzle 111 to inject the reducing agent into the upstream pipe of the second selective catalytic reduction device 104, so as to prompt the second selective catalytic reduction device 104 to convert NOx through the catalyst.

The application provides an after-treatment system, when the engine cold start, the temperature among the after-treatment system has not reached injection system's the temperature of spouting yet, utilizes the electrical heating catalyst converter to heat, lets selective catalytic reduction device's upstream pipeline temperature reach injection system's the temperature of spouting fast. And regulating and controlling a nozzle of the injection system to inject the reducing agent so as to convert the NOx in the selective catalytic reduction device. Meanwhile, the temperature of the particle catcher can be quickly and quickly reached to the temperature required by passive regeneration and active regeneration. Therefore, the temperature of the aftertreatment system is rapidly increased through the electric heating catalyst, the strategy of regulating and controlling the injection system is better, the conversion efficiency of NOx in engine tail gas and the regeneration efficiency of the particle catcher are improved, and the emission of harmful substances in the engine tail gas is reduced.

Alternatively, in another embodiment of the present application, another embodiment of the aftertreatment system described above, as shown in FIG. 2, the electrically heated catalyst and the first SCR device are combined into one and collectively configured as an electrically heated catalyst 115, also referred to as an EHC/SCR, having an SCR reduction catalyst coated on a surface thereof.

It should be noted that the original electrically heated catalyst and the first selective catalytic reduction device are integrated into one unit by coating the surface of the electrically heated catalyst with the reduction catalyst. For example, the electrically heated catalyst is immersed in a vessel containing the reducing catalyst for a certain period of time to ensure the catalyst loading rate on the heating wire, thereby coating the reducing catalyst on the surface of the electrically heated catalyst. Therefore, the electric heating catalytic converter is the electric heating catalytic converter with the reduction catalysis function, and meanwhile, the use of parts can be reduced, so that the space and the cost are saved.

It should be further noted that, the electrically heated catalyst 115 coated with the SCR reduction catalyst and the first nozzle 109 are disposed behind the turbine of the engine 113 in a close-coupled arrangement, so that the distance between the electrically heated catalyst 115 coated with the SCR reduction catalyst and the engine 113 can be shortened, the engine 113 can transfer heat more quickly, and the NOx conversion efficiency can be improved.

Alternatively, in another embodiment of the present application, in another implementation of the aftertreatment system described above and shown in fig. 3, the second scr device includes: the second selective catalytic reduction device is integrated with the ammonia processor device 116, which may also be referred to as an SCR/ASC.

It should be noted that the second scr device is integrated with the ammonia gas processor, so that NOx in the converted engine exhaust gas can be treated simultaneously with ammonia gas in the engine exhaust gas, and space can be saved.

Alternatively, in another embodiment of the present application, another implementation of the aftertreatment system described above, as shown in FIG. 4, uses a NOx adsorber (Passive NO)_xAbsorber, PNA)117 instead of the oxidation catalyst 106.

The NOx adsorber 117 may adsorb NOx at the time of cold start of the engine, and may reduce NOx emission until the temperature does not reach the temperature at which the injection system starts injection. After the electrically heated catalyst 115, which is coated with the SCR catalyst, is heated to raise the temperature to the temperature at which the injection system starts injecting, the NOx adsorber 117 may release the adsorbed NOx, which is converted by the selective catalytic reduction device.

Another embodiment of the present application further provides a control method of an aftertreatment system, which is applied to an electronic control unit, and as shown in fig. 5, the control method of the aftertreatment system specifically includes:

s501, detecting a first temperature parameter and a second temperature parameter in the post-processing system; wherein the first temperature parameter is an upstream temperature parameter of the first selective catalytic reduction device and the second temperature parameter is an upstream temperature parameter of the second selective catalytic reduction device; the second selective catalytic reduction device is located downstream of the first selective catalytic reduction device.

It should be noted that, by the first temperature sensor and the second temperature sensor mentioned in the above-mentioned aftertreatment system, the upstream temperature parameter of the first selective catalytic reduction device, that is, the first temperature parameter, and the upstream temperature parameter of the second selective catalytic reduction device, that is, the second temperature parameter, are respectively detected. Wherein the second selective catalytic reduction device is located downstream of the first selective catalytic reduction device.

S502, if the first temperature parameter is detected to be lower than a preset first temperature threshold value, starting the electric heating catalytic converter; wherein the first temperature threshold is the start-up temperature of the injection system; the electrically heated catalyst is used for heating the reduction catalyst of the first selective catalytic reduction device.

It should be noted that the first temperature threshold is the start-up temperature of the injection system, and if the first temperature sensor detects that the upstream temperature parameter of the first selective catalytic reduction device is lower than the start-up temperature of the injection system, the electronic control unit starts the electric heating catalyst to heat, so as to quickly raise the temperature of the first selective catalytic reduction device, so that the temperature of the first selective catalytic reduction device reaches the start-up temperature of the injection system as soon as possible, improve the conversion efficiency of NOx, and reduce the emission of NOx. While also elevating the temperature of other components in the aftertreatment system.

S503, regulating and controlling whether a nozzle in the injection system injects the reducing agent or not according to the first temperature parameter and the second temperature parameter.

It should be noted that whether the injection nozzle of the injection system injects the reducing agent is related to the first temperature parameter and the second temperature parameter. When the first temperature parameter and the second temperature parameter do not reach the start-up temperature of the injection system, the nozzle of the injection system does not inject the reducing agent, because the selective catalytic reduction device cannot obviously convert NOx before the temperature, and therefore, the reducing agent is injected before the temperature, which wastes resources. After the first temperature parameter or the second temperature parameter reaches the start-up temperature of the injection system, the electronic control unit can intelligently regulate and control the injection system to control the nozzle to inject the reducing agent according to the specific values of the first temperature parameter and the second temperature parameter, and resources can be saved while NOx is efficiently converted.

The application provides a control method of an aftertreatment system, which detects an upstream temperature parameter of a first selective catalytic reduction device and an upstream temperature parameter of a second selective catalytic reduction device in the aftertreatment system, wherein the second selective catalytic reduction device is located at the downstream of the first selective catalytic reduction device. And if the upstream temperature parameter of the first selective catalytic reduction device is detected to be lower than the start-up temperature of the injection system, starting the electric heating catalyst to heat the reduction catalyst of the first selective catalytic reduction device. And optimizing and regulating a strategy for injecting the reducing agent by a nozzle in the injection system according to the upstream temperature parameter of the first selective catalytic reduction device and the upstream temperature parameter of the second selective catalytic reduction device. Therefore, the temperature of the aftertreatment system is quickly raised through the electric heating catalyst, and the strategy of regulating and controlling the injection system is better, so that the conversion efficiency of nitrogen oxides in the engine tail gas and the regeneration efficiency of the particle catcher are improved, and the emission of harmful substances in the engine tail gas is reduced.

Optionally, in another embodiment of the present application, after performing S502, the method may further include:

in the starting process of the electric heating catalytic converter, if the detected first temperature parameter reaches a first temperature threshold value, the electric heating catalytic converter is closed.

It should be noted that the temperature sensor of the aftertreatment system continuously detects that the electrically heated catalyst is turned off during the start-up process of the electrically heated catalyst if the detected upstream temperature parameter of the first scr device reaches the start-up temperature of the injection system. Because the heat generated by the running of the engine can be transferred to the aftertreatment system, the temperature of the aftertreatment system is improved, the energy consumption of the electric heating catalyst is high, and the electric heating catalyst can be turned off to save the cost. If the first temperature sensor detects that the upstream temperature parameter of the first selective catalytic reduction device is lower than the start-up temperature of the injection system again, the electrically heated catalyst is started again.

Optionally, in another embodiment of the present application, an implementation manner of step S503 may include:

if the first temperature parameter and the second temperature parameter are both smaller than a first temperature threshold value, closing a first nozzle and a second nozzle in the injection system; the first nozzle is used for injecting a reducing agent to an upstream pipeline of the first selective catalytic reduction device, and the second nozzle is used for injecting the reducing agent to an upstream pipeline of the second selective catalytic reduction device.

It should be noted that when the upstream temperature parameter of the first selective catalytic reduction device and the upstream temperature parameter of the second selective catalytic reduction device are both less than the start-up temperature of the injection system, both nozzles of the injection system are closed, because the selective catalytic reduction device cannot obviously convert NOx before the temperature, and therefore, the injection of the reducing agent is a waste resource before the temperature.

And if the first temperature parameter is greater than the first temperature threshold and the second temperature parameter is less than a preset first temperature threshold, starting the first nozzle and closing the second nozzle.

It should be noted that when the upstream temperature parameter of the first scr device reaches the start-up temperature of the injection system and the upstream temperature parameter of the second scr device is less than the start-up temperature of the injection system, the first injector is activated and the second injector is deactivated, because only the first scr device can perform a significant NOx conversion using the reducing agent. In this case the injection quantity of the first nozzle would be somewhat higher, and by sacrificing the injection quantity of the reducing agent, NOx emissions during cold start are reduced as much as possible.

If the first temperature parameter and the second temperature parameter are both greater than the first temperature threshold and the second temperature parameter is less than the second temperature threshold, simultaneously starting the first nozzle and the second nozzle; the second temperature threshold is the temperature for efficient conversion of the oxynitride, and is greater than the first temperature threshold.

It should be noted that when the upstream temperature parameter of the first selective catalytic reduction device and the upstream temperature parameter of the second selective catalytic reduction device both reach the start-up temperature of the injection system, and the upstream temperature parameter of the second selective catalytic reduction device is less than the temperature at which the nitrogen oxide is efficiently converted, the first nozzle and the second nozzle are simultaneously activated. At the moment, the two selective catalytic reduction devices are utilized to simultaneously convert NOx, so that the conversion efficiency of the NOx is improved.

It should be noted that, when the upstream temperature parameter of the first selective catalytic reduction device is less than the temperature at which the nitrogen oxide compound is efficiently converted and the upstream temperature parameter of the second selective catalytic reduction device reaches the temperature at which the nitrogen oxide compound is efficiently converted, the second nozzle is activated and the first nozzle is closed. Since the second selective catalytic reduction device has reached the high-efficiency conversion efficiency region at this time, the NOx reduction ability is significantly improved, and NOx emission can be reduced only by injecting the reducing agent upstream of the second selective catalytic reduction device, so that the first injection nozzle can be closed to save resources.

Optionally, in another embodiment of the application, the method for controlling the aftertreatment system may further include:

during operation of the aftertreatment system, a differential pressure parameter of the particle trap is sensed.

It should be noted that the particle trap is provided with a differential pressure sensor for detecting a differential pressure parameter in the particle trap, and during the operation of the aftertreatment system, the differential pressure parameter of the particle trap is detected in real time, and the carbon deposition value of the particle trap is reflected according to the differential pressure parameter, so as to determine whether to perform passive regeneration and active regeneration of the particle trap.

If the pressure difference parameter reaches a preset first pressure difference threshold value, starting the electric heating catalytic converter and closing an exhaust valve; wherein the preset first pressure difference threshold is a threshold for the particle trap to reach passive regeneration.

It should be noted that, if the differential pressure sensor detects that the differential pressure parameter in the particle trap reaches the threshold value of passive regeneration, the electrically heated catalyst is started to heat, the exhaust valve is closed in advance, the exhaust gas residue in the cylinder is mixed with the fresh mixed gas in the air intake process, and due to the existence of negative compression power, correspondingly, in order to avoid large power loss, the opening time of the intake valve is correspondingly delayed, so that the temperature of the aftertreatment system is increased, the required temperature of passive regeneration is quickly reached, the efficiency of passive regeneration is further improved, and the required time of passive regeneration is reduced.

In the starting process of the electric heating catalytic converter, if the detected pressure difference parameter of the particle catcher is lower than a preset second pressure difference threshold value, the electric heating catalytic converter is closed; wherein the preset second differential pressure threshold is smaller than the preset first differential pressure threshold.

It should be noted that, during the process of starting the electrically heated catalyst for passive regeneration, if the pressure difference parameter of the particle trap is detected to be lower than the limit value for which passive regeneration is not required, the electrically heated catalyst is turned off. Wherein the limit is less than the threshold for passive regeneration.

Optionally, in another embodiment of the present application, the method for controlling an aftertreatment system may further include:

If the pressure difference parameter reaches a preset third pressure difference threshold value, starting the electric heating catalytic converter, and starting an injection system to inject fuel or controlling an engine to inject fuel after a cylinder; wherein the preset third pressure difference threshold is a threshold for the particle trap to reach active regeneration.

It should be noted that, if the differential pressure sensor detects that the differential pressure parameter in the particle trap reaches the threshold value of the active regeneration, the electrically heated catalyst is started to heat until the temperature of the upstream of the oxidation catalyst is higher than the ignition temperature of the fuel oil, and the fuel oil can be ignited rapidly after being oxidized by the oxidation catalyst, so as to increase the temperature rapidly to reach the temperature of the active regeneration, which is generally 650 ℃ to 750 ℃. After the hydrocarbon is oxidized by the oxidation type catalyst, heat can be released, and oxygen and nitrogen dioxide enter the particle catcher and then react with carbon particles better under the heating condition to generate carbon dioxide and nitric oxide, so that the high efficiency and the thoroughness of active regeneration are ensured.

And in the process of starting the electric heating catalytic converter for active regeneration, the electric heating catalytic converter is closed after fuel ignition is detected. The temperature parameter detected by the temperature sensor can be used as the basis for judging the fuel ignition.

Another embodiment of the present application further provides a control device of an aftertreatment system, as shown in fig. 6, specifically including:

a detection unit 601 for detecting a first temperature parameter and a second temperature parameter in the post-processing system; wherein the first temperature parameter is an upstream temperature parameter of a first selective catalytic reduction device and the second temperature parameter is an upstream temperature parameter of a second selective catalytic reduction device; the second selective catalytic reduction device is located downstream of the first selective catalytic reduction device.

A starting unit 602, configured to start the electrically heated catalyst if the detecting unit detects that the first temperature parameter is lower than a preset first temperature threshold; wherein the first temperature threshold is the start-up temperature of the injection system.

And a regulating unit 603, configured to regulate whether a nozzle in the injection system injects a reducing agent according to the first temperature parameter and the second temperature parameter.

The control device of the aftertreatment system detects an upstream temperature parameter of a first selective catalytic reduction device and an upstream temperature parameter of a second selective catalytic reduction device in the aftertreatment system through a detection unit 601, wherein the second selective catalytic reduction device is located at the downstream of the first selective catalytic reduction device. If it is detected that the upstream temperature parameter of the first scr device is lower than the start-up temperature of the injection system, the starting unit 602 starts the electrically heated catalyst to heat the reduction catalyst of the first scr device. The regulating unit 603 optimizes and regulates a strategy for injecting the reducing agent through a nozzle in the injection system according to the upstream temperature parameter of the first selective catalytic reduction device and the upstream temperature parameter of the second selective catalytic reduction device. Therefore, the temperature of the aftertreatment system is quickly raised through the electric heating catalyst, and the strategy of regulating and controlling the injection system is better, so that the conversion efficiency of nitrogen oxides in the engine tail gas and the regeneration efficiency of the particle catcher are improved, and the emission of harmful substances in the engine tail gas is reduced.

In this embodiment, the specific implementation processes of the detecting unit 601, the starting unit 602, and the adjusting unit 603 can refer to the contents of the method embodiment corresponding to fig. 5, which are not described herein again.

Optionally, in another embodiment of the present application, the method further includes:

and the closing subunit is used for closing the electric heating catalytic converter if the detected first temperature parameter reaches a first temperature threshold value in the starting process of the electric heating catalytic converter.

In this embodiment, the specific execution process of the sub-unit is turned off, which can be referred to the content of the corresponding method embodiment described above and is not described herein again.

Optionally, in another embodiment of the present application, the adjusting unit 603 includes:

the first control subunit is used for closing the first nozzle and the second nozzle in the injection system if the first temperature parameter and the second temperature parameter are both smaller than a first temperature threshold value; the first nozzle is used for injecting a reducing agent to an upstream pipeline of the first selective catalytic reduction device, and the second nozzle is used for injecting a reducing agent to an upstream pipeline of the second selective catalytic reduction device;

the second control subunit is used for starting the first nozzle and closing the second nozzle if the first temperature parameter is greater than the first temperature threshold and the second temperature parameter is less than a preset first temperature threshold;

the third control subunit is used for simultaneously starting the first nozzle and the second nozzle if the first temperature parameter and the second temperature parameter are both greater than the first temperature threshold value and the second temperature parameter is less than the second temperature threshold value; the second temperature threshold is the temperature for efficient conversion of the oxynitride, and is greater than the first temperature threshold;

and the fourth control subunit is used for starting the second nozzle and closing the first nozzle if the first temperature parameter is greater than the first temperature threshold and the second temperature parameter is greater than the second temperature threshold.

In this embodiment, for specific implementation processes of the first control subunit, the second control subunit, the third control subunit, and the fourth control subunit, reference may be made to the contents of the corresponding method embodiments described above, and details are not described here.

Optionally, in another embodiment of the present application, the control device of the aftertreatment system may further include:

and the second detection unit is used for detecting the pressure difference parameter of the particle catcher in the operation process of the post-processing system.

The first control unit is used for starting the electric heating catalytic converter and closing the exhaust valve if the pressure difference parameter reaches a preset first pressure difference threshold value; wherein the preset first pressure difference threshold is a threshold for the particle trap to reach passive regeneration.

The second control unit is used for closing the electric heating catalytic converter if the detected pressure difference parameter of the particle catcher is lower than a preset second pressure difference threshold value in the starting process of the electric heating catalytic converter; wherein the preset second differential pressure threshold is smaller than the preset first differential pressure threshold.

In this embodiment, for specific implementation processes of the second detection unit, the first control unit, and the second control unit, reference may be made to the contents of the corresponding method embodiments described above, and details are not described here.

and the third detection unit is used for detecting the pressure difference parameter of the particle catcher in the operation process of the post-processing system.

The third control unit is used for starting the electric heating catalytic converter and starting the injection system to inject fuel or controlling the engine to inject fuel after the cylinder if the differential pressure parameter reaches a preset third differential pressure threshold value; wherein the preset third pressure difference threshold is a threshold at which the particle trap reaches active regeneration.

In this embodiment, for specific implementation processes of the third detecting unit and the third controlling unit, reference may be made to the contents of the corresponding method embodiments described above, and details are not described here again.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

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

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

Claims

1. A method of controlling an aftertreatment system, comprising:

2. The method of claim 1, wherein after activating the electrically heated catalyst if the first temperature parameter is detected to be below a predetermined first temperature threshold, further comprising:

3. The method of any one of claims 1 to 2, further comprising:

4. The method of any one of claims 1 to 2, further comprising:

5. A control apparatus for an aftertreatment system, comprising:

a first regulating unit, configured to close a first nozzle and a second nozzle in the injection system if the first temperature parameter and the second temperature parameter are both less than the first temperature threshold; wherein the first nozzle is used for injecting the reducing agent to an upstream pipeline of a first selective catalytic reduction device, and the second nozzle is used for injecting the reducing agent to an upstream pipeline of a second selective catalytic reduction device;

the second regulating and controlling unit is used for starting the first nozzle and closing the second nozzle if the first temperature parameter is greater than the first temperature threshold and the second temperature parameter is less than a preset first temperature threshold;

the third regulating and controlling unit is used for simultaneously starting the first nozzle and the second nozzle if the first temperature parameter and the second temperature parameter are both greater than the first temperature threshold and the second temperature parameter is less than a second temperature threshold; the second temperature threshold is the temperature for efficient conversion of nitrogen oxides, and is greater than the first temperature threshold;

and the fourth regulating and controlling unit is used for starting the second nozzle and closing the first nozzle if the first temperature parameter is greater than the first temperature threshold and the second temperature parameter is greater than the second temperature threshold.

6. An aftertreatment system, comprising:

an electronic control unit for performing the method of any one of claims 1 to 4;

7. The aftertreatment system of claim 6, wherein the electrically heated catalyst and the first set of selective catalytic reduction devices are configured to: an electrically heated catalyst having a surface coated with a reduction catalyst.

8. The aftertreatment system of claim 6, wherein the second selective catalytic reduction device comprises: the second selective catalytic reduction device is an integrated device with the ammonia gas processor.

9. The aftertreatment system of claim 6, wherein the particle trap comprises: a particle trap coated with a reduction catalyst.