CN210003364U - a post-processing system - Google Patents

Abstract

The post-processing system provided by the utility model is applied to the technical field of automobiles. The system includes a main pipeline, a bypass pipeline and a controller. The main pipeline includes an SCR, a supercharger and a first temperature sensor; the intake air of the bypass pipeline The port is set upstream of the supercharger, and the air outlet is set upstream of the SCR, including a solenoid valve, H-cat, a first urea nozzle and a second temperature sensor, the controller is when the intake air temperature of the SCR is less than the first preset temperature threshold , send the first control signal to open the solenoid valve, and send the second control signal under the condition that the exhaust gas temperature in the bypass pipeline is not less than the second preset temperature threshold, so that the first urea nozzle sprays urea solution, and the bypass pipeline The temperature of the exhaust gas is relatively high, and the second preset temperature threshold is lower than the first preset temperature threshold, so that the first urea nozzle sprays the urea solution in advance, accelerates the hydrolysis and gasification under the action of H-cat, and increases the ammonia reserve in the SCR , and improve the treatment efficiency of SCR for _NOx .

Description

a post-processing system

technical field

The utility model belongs to the technical field of automobiles, in particular to a post-processing system.

Background technique

SCR (Selective Catalytic Reduction, Selective Oxidation Reduction) is a widely used exhaust gas treatment technology in the diesel engine aftertreatment system. By setting SCR, the _NOx (nitrogen oxides) in the exhaust gas can be accelerated and reduced, and the oxidation reaction can be effectively inhibited. The _NOx conversion rate can reach 90% without reducing the engine efficiency, and has the advantages of better fuel economy and high sulfur resistance.

When SCR is used for exhaust gas treatment, the post-treatment system sprays urea solution into the exhaust gas entering the SCR through the urea nozzle, and the ammonia gas and _NOx produced by the hydrolysis and gasification of the urea solution undergo catalytic reduction reaction and finally generate harmless nitrogen and water. In the prior art, the spray control of the urea solution is set according to the temperature of the exhaust gas, and the urea solution is sprayed only when the temperature of the exhaust gas reaches a preset temperature threshold.

Therefore, when the engine is cold started or other operating conditions with low exhaust gas temperature, the urea solution cannot be sprayed in time, resulting in a low treatment efficiency of _{NOx by} the aftertreatment system, and even affecting the overall emission performance of the vehicle.

Utility model content

In view of this, the purpose of this utility model is to provide a kind of aftertreatment system, improve the _NOx treatment efficiency under the cold start of the engine or other working conditions with low exhaust gas temperature, and improve the emission performance of the vehicle, the specific scheme is as follows:

The utility model provides a post-processing system, comprising: a main pipeline, a bypass pipeline and a controller, wherein,

the main circuit includes a supercharger, a selective redox SCR, and a first temperature sensor;

the supercharger is arranged between the engine exhaust port and the SCR;

The first temperature sensor is arranged at the intake port of the SCR, and collects the intake air temperature of the intake port of the SCR;

The air inlet of the bypass line is arranged upstream of the supercharger, the air outlet is arranged upstream of the SCR, and the bypass line includes a valve for controlling the opening and closing of the bypass line. Solenoid valve, hydrolysis catalyst H-cat, first urea nozzle, and second temperature sensor;

The first urea nozzle and the second temperature sensor are both arranged upstream of the H-cat, wherein the second temperature sensor is used to collect the temperature of the exhaust gas in the bypass pipeline;

The controller receives the feedback values of the first temperature sensor and the second temperature sensor, and sends a control signal to the solenoid valve under the condition that the intake air temperature of the SCR is lower than the first preset temperature threshold The first control signal that the solenoid valve is opened is sent to the first urea nozzle to control the spraying of the first urea nozzle under the condition that the exhaust gas temperature in the bypass pipeline is not less than the second preset temperature threshold The second control signal of the urea solution, wherein the second preset temperature threshold is lower than the first preset temperature threshold.

Optionally, the main circuit further includes:

a second urea nozzle arranged at the SCR air inlet;

The controller is further configured to send a third control signal for controlling the closing of the solenoid valve to the solenoid valve under the condition that the intake air temperature of the SCR is not less than the first preset temperature threshold, and send the third control signal to the solenoid valve. The first urea nozzle sends a fourth control signal for controlling the closing of the first urea nozzle, and a fifth control signal for controlling the second urea nozzle to spray urea solution is sent to the second urea nozzle.

Optionally, the solenoid valve is arranged upstream of the H-cat.

Optionally, the injection amount of the first urea nozzle is smaller than the injection amount of the second urea nozzle.

Optionally, the main circuit further includes: a combination of a NOx adsorber PNA or a diesel oxidation catalyst DOC and a diesel particulate filter DPF, wherein the NOx adsorber PNA or a combination of the DOC and the DPF is provided between the supercharger and the SCR.

Optionally, the first urea nozzle and the second urea nozzle are connected to the same urea supply system.

Optionally, the first urea nozzle and the second urea nozzle are respectively connected to their corresponding urea supply systems.

Optionally, the urea supply system includes a urea tank and a urea pump.

Based on the above technical solutions, the aftertreatment system provided by the present invention includes a main pipeline, a bypass pipeline and a controller. The main pipeline includes an SCR, a supercharger arranged between the engine exhaust port and the SCR, and a The intake port of the SCR is the first temperature sensor used to collect the intake temperature of the intake port of the SCR; the intake port of the bypass line is set upstream of the supercharger, and the outlet port is set upstream of the SCR to achieve the same pressure as the supercharger. the parallel connection of the devices, and the bypass pipeline includes a solenoid valve for controlling the opening and closing of the bypass pipeline, H-cat, a first urea nozzle and a second temperature sensor arranged upstream of the H-cat, wherein the first urea nozzle is The second temperature sensor is used to collect the temperature of the exhaust gas in the bypass pipeline; the controller receives the feedback value of the first temperature sensor and the second temperature sensor. When the engine is cold started or other operating conditions with low exhaust gas temperature, the intake air temperature of the SCR When the temperature is less than the first preset temperature threshold, the controller sends a first control signal to the solenoid valve, the solenoid valve opens after receiving the first control signal, and a part of the exhaust gas is taken from the main pipeline into the bypass pipeline, and the exhaust gas temperature in the bypass pipeline is Under the working condition not less than the second preset temperature threshold, the second control signal is sent to the first urea nozzle, and the first urea nozzle starts to work after receiving the second control signal, and sprays the urea solution.

Since the exhaust gas in the bypass pipeline does not flow through the supercharger, no heat loss will be caused, the temperature of the exhaust gas in the bypass pipeline is relatively high, and at the same time, the second preset temperature threshold is lower than the first preset temperature threshold, The first urea nozzle can be made to spray urea solution in advance, and the exhaust gas with higher mixing temperature of urea solution flows through H-cat, and then enters SCR after accelerated hydrolysis and gasification under the action of H-cat. It can effectively improve the treatment efficiency of SCR for _NOx , and improve the emission performance of the vehicle under cold start or other conditions with low exhaust gas temperature.

Description of drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative efforts.

1 is a structural block diagram of a post-processing system provided by an embodiment of the present invention;

FIG. 2 is a structural block diagram of another post-processing system provided by an embodiment of the present invention.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. The embodiments described above are a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

Referring to FIG. 1, FIG. 1 is a structural block diagram of a post-processing system provided by an embodiment of the present application. The post-processing system provided by an embodiment of the present application specifically includes: a main pipeline 10, a bypass pipeline 20, and a controller (in the figure not shown), where,

The intake port of the main line 10 is connected with the exhaust port of the engine (not shown in the figure), and directly processes the exhaust gas discharged from the engine. The main circuit 10 includes a supercharger 101 , a Selective Catalytic Reduction (SCR) 102 , and a first temperature sensor 103 .

Specifically, the supercharger 101 is disposed between the exhaust port of the engine and the SCR 102 , that is, the supercharger 101 and the SCR 102 are connected in series in sequence. Optionally, referring to FIG. 1 , in the post-treatment system provided with SCR, a PNA (Passive NOx Absorber, NO _x adsorber) 30 is often provided, and the treatment of NO _x gas under the condition of low exhaust temperature is realized by the PNA30, and the PNA30 It is provided between the supercharger 101 and the SCR 102 . Further, in some post-processing systems, other post-processing components are also arranged between the PNA and the SCR, which will not be repeated here.

The first temperature sensor 103 is disposed at the intake port of the SCR 102 for collecting the intake air temperature of the intake port of the SCR 102 .

The air inlet of the bypass line 20 is arranged upstream of the supercharger 101 and is connected to the main line 10, and the air outlet of the bypass line 20 is arranged upstream of the SCR102, and is also connected to the main line 10, that is, bypass The pipeline 20 and the supercharger 101 are connected in parallel between the engine exhaust port and the SCR102. If a PNA30 is provided in the main pipeline, the bypass pipeline 20 is connected in parallel with the supercharger 101 and the PNA30 to the engine exhaust port and the SCR102. between.

Further, the bypass line 20 includes a solenoid valve 201, an H-cat (Hydrolysis Catalyst, hydrolysis catalyst) 202, a first urea nozzle 203, and a second temperature sensor 204, wherein,

The solenoid valve 201 is used to control the opening and closing of the bypass pipeline 20 according to the received control signal sent by the controller. Optionally, in order to effectively control the exhaust gas flowing through the H-cat 202, the solenoid valve 201 is arranged in the H-cat Upstream, near the junction of the bypass line 20 and the main line 10.

The first urea nozzle 203 and the second temperature sensor 204 are both arranged upstream of the H-cat 202, wherein the first urea nozzle 203 is used to spray urea solution into the bypass pipeline 20, and the second temperature sensor 204 is used to collect the bypass The temperature of the exhaust gas in the pipeline 20.

During the operation of the aftertreatment system provided by the present invention, the controller receives the feedback values of the first temperature sensor 103 and the second temperature sensor 204, and under the condition that the intake air temperature of the SCR102 is lower than the first preset temperature threshold (this time The engine may be in a cold start condition or other conditions where the exhaust gas temperature is low), the first control signal for controlling the opening of the solenoid valve 201 is sent to the solenoid valve 201, so that the solenoid valve 201 is opened, and then the bypass line 20 is opened. Connected, a small part of the engine exhaust gas can directly enter the bypass line 20 without going through the supercharger 101 , and finally flow into the SCR 102 via the bypass line 20 .

In addition, the controller can also monitor the temperature of the exhaust gas in the bypass pipeline 20 according to the measurement value sent by the second temperature sensor 204, and send the temperature to the exhaust gas temperature in the bypass pipeline 20 under the condition that the temperature of the exhaust gas in the bypass pipeline 20 is not less than the second preset temperature threshold. The first urea nozzle 203 sends a second control signal to control the first urea nozzle 203 to spray the urea solution. It should be noted that, in order to make the first urea nozzle 203 in the bypass pipeline 20 spray the urea solution in advance, the second preset temperature threshold is lower than the first preset temperature threshold.

When the engine is cold started or under other operating conditions with low exhaust gas temperature, the bypass line 20 is controlled to be connected. Since the exhaust gas in the bypass line 20 does not flow through the supercharger 101, no heat loss will be caused, and the bypass The temperature of the exhaust gas in the pipeline 20 is relatively high, and at the same time, the second preset temperature threshold value is lower than the first preset temperature threshold value, so that the first urea nozzle 203 can spray the urea solution in advance, and the exhaust gas with the higher urea solution mixing temperature flows through H-cat202, under the action of H-cat202, accelerates hydrolysis and gasification and then enters SCR102, increasing the ammonia storage capacity in SCR102, which can effectively improve the treatment efficiency of SCR102 for _NOx , and improve the cold start of vehicles or other low exhaust gas temperatures emission performance under the conditions.

Optionally, after the engine continues to work for a period of time, the temperature of the exhaust gas entering the aftertreatment system will gradually increase. Therefore, in order to ensure that the SCR 102 in the after-treatment system can work normally after the engine exhaust temperature rises, the after-treatment system provided by the embodiment of the present invention further includes a second urea nozzle 104 . The second urea nozzle 104 is arranged at the intake port of the SCR102, and the controller sends a third control signal to the solenoid valve 201 to control the solenoid valve 201 to close under the condition that the intake air temperature of the SCR102 is not less than the first preset temperature threshold, A fourth control signal for controlling the closing of the first urea nozzle 203 is sent to the first urea nozzle 203 , and at the same time, a fifth control signal for controlling the second urea nozzle to spray urea solution is sent to the second urea nozzle 104 .

When the exhaust gas temperature in the aftertreatment system is high enough (not less than the first preset temperature threshold), the aftertreatment system provided by the embodiment of the present invention can close the bypass line 20, make the main line 10 work alone, and It does not affect the treatment effect of the aftertreatment system on the exhaust gas.

It should be noted that, in the present utility model, the controller receives the measured values of the first temperature sensor and the second temperature sensor, and sends corresponding control signals to the solenoid valve, the first urea nozzle and the second urea nozzle, all of which belong to the current state of the art. There is technology. For example, the data feedback lines of the first temperature sensor and the second temperature sensor can be directly connected to the corresponding pins of the controller, and the controller reads the voltage or resistance value changes of the corresponding pins, and then obtains the corresponding temperature value. The temperature measurement technology in the prior art is obviously achievable; for another example, the pins of the controller are connected to the control terminals of the solenoid valve, the first urea nozzle and the second urea nozzle, and the corresponding control signals can be preset. For high-level or low-level signals, the controller controls the action of the controlled mechanism by outputting high-level or low-level signals, which is also the prior art.

The process that the controller compares the received temperature value with the preset threshold value can be implemented by a numerical comparator in the prior art, and no creative improvement is required. Therefore, although in the present invention, the controller needs to be realized by program programming, these programs can be realized by referring to the prior art. It should be emphasized that the key of the present invention is to improve the structure of the main pipeline of the post-processing system in the prior art, add a bypass pipeline, and set the H-cat and the first urea nozzle in the bypass pipeline, so that the When the engine is cold-started or other operating conditions with low exhaust gas temperature, the ammonia storage amount in the SCR can be effectively increased, thereby effectively improving the treatment efficiency of the SCR for _NOx .

Optionally, according to the above description of the working process of the post-treatment system provided by the embodiment of the present invention, it can be known that the first urea nozzle is arranged in the bypass pipeline, and the exhaust gas flow in the bypass pipeline is small and the temperature is low, which is very suitable for The requirements for the conversion efficiency of _NOx gas are also low, and the second urea nozzle is arranged in the main pipeline, the exhaust gas flow rate is large and the temperature is high, and the conversion efficiency requirements for _NOx gas are also high. Therefore, the injection amount of the first urea nozzle can be smaller than the injection amount of the second urea nozzle, so as to achieve the purpose of saving cost.

Optionally, there are various options for the urea supply system to which the first urea nozzle and the second urea nozzle are connected. The first urea nozzle and the second urea nozzle can be connected to the same urea supply system, of course, the two can also be connected to their corresponding urea supply systems, and different urea supply systems are used to achieve urea supply.

Optionally, the aforementioned urea system at least includes a urea tank and a urea pump, wherein the urea tank is used to store the urea solution, and the urea pump is used to provide the urea solution with a preset pressure to the corresponding urea nozzle.

As mentioned above, the post-processing system may include different post-processing components. Referring to FIG. 2, FIG. 2 is another post-processing system provided by the embodiment of the present invention. The illustrated embodiment is based on the embodiment shown in FIG. 1, replacing PNA30 with a combination of DOC (Diesel Oxidation Catalyst, Diesel Engine Oxidation Catalyst) and DPF (Diesel Particulate Filter, Diesel Engine Particulate Filter), that is, the DOC and the A combination of DPFs is provided between the supercharger 101 and the SCR 102 . In the figure, it is represented by DOC+DPF, and the symbol is 40. The working process of the post-processing system shown in FIG. 2 is basically the same as that of the post-processing system shown in FIG. 1 , and will not be repeated here.

It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. For the same and similar parts among the various embodiments, refer to each other Can.

It should also be noted that in this document, relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply those entities or operations There is no such actual relationship or order between them. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion, but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in the article or device that includes the element.

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

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. These improvements and Retouching should also be regarded as the protection scope of the present invention.

Claims (8)

1, post-treatment system, comprising a main pipeline, a bypass pipeline and a controller, wherein,

the main pipeline comprises a supercharger, a selective oxidation-reduction device (SCR) and an temperature sensor;

the supercharger is arranged between an exhaust port of the engine and the SCR;

the th temperature sensor is arranged at an air inlet of the SCR and used for collecting the air inlet temperature of the SCR air inlet;

the air inlet of the bypass pipeline is arranged at the upstream of the supercharger, the air outlet of the bypass pipeline is arranged at the upstream of the SCR, and the bypass pipeline comprises an electromagnetic valve for controlling the opening and closing of the bypass pipeline, a hydrolysis catalyst H-cat, an th urea nozzle and a second temperature sensor;

the th urea nozzle and the second temperature sensor are both arranged at the upstream of the H-cat, wherein the second temperature sensor is used for collecting the temperature of tail gas in the bypass pipeline;

the controller receives temperature sensor with the feedback value of second temperature sensor the SCR's inlet air temperature is less than and predetermines under the temperature threshold operating mode, to the solenoid valve sends and is used for controlling the control signal that the solenoid valve opened, and is in under the tail gas temperature is not less than the second and predetermines under the temperature threshold operating mode in the bypass line, to urea nozzle sends control urea nozzle sprays the second control signal of urea solution, wherein, the second is predetermine the temperature threshold and is less than and predetermines the temperature threshold.

2. The aftertreatment system of claim 1, wherein the main pipeline further comprises:

the second urea nozzle is arranged at the SCR air inlet;

the controller is further used for sending a third control signal for controlling the electromagnetic valve to be closed, sending a fourth control signal for controlling the urea nozzle to be closed to the urea nozzle, and sending a fifth control signal for controlling the second urea nozzle to spray urea solution under the working condition that the air inlet temperature of the SCR is not less than the preset temperature threshold value.

3. The aftertreatment system of claim 1, wherein the solenoid valve is disposed upstream of the H-cat.

4. The aftertreatment system of claim 2, wherein an injection quantity of the -th urea nozzle is less than an injection quantity of the second urea nozzle.

5. The aftertreatment system of claim 1, wherein the main pipeline further comprises: a combination of a NOx adsorber PNA or a diesel oxidation catalyst DOC and a diesel particulate trap DPF, wherein said NOx adsorber PNA or said DOC and said DPF combination is arranged between said supercharger and said SCR.

6. The aftertreatment system of claim 2, wherein the -th urea nozzle and the second urea nozzle are connected to a common urea supply system.

7. The aftertreatment system of claim 2, wherein the -th and second urea nozzles are each connected to a respective urea supply system.

8. The aftertreatment system of claim 6 or 7, wherein the urea supply system includes a urea tank and a urea pump.

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