JP2021046824A - Exhaust emission control system - Google Patents

Abstract

To prevent a user from misunderstanding that a system is failed during reductant thawing control.SOLUTION: An exhaust emission control system for cleaning an exhaust gas flowing through an exhaust passage with urea water includes: a tank for storing urea water; a freezing determination unit 123 for determining whether urea water freezes in the tank; a thawing control unit 124 for performing thawing control of thawing urea water when it is determined that urea water freezes; and a notification control unit 125 for notifying a user that thawing control is in operation when the thawing control unit performs thawing control for urea water.SELECTED DRAWING: Figure 3

Description

The present invention relates to an exhaust gas purification system.

The vehicle is equipped with an exhaust purification system that injects a reducing agent (for example, urea water) into an exhaust passage through which the exhaust gas flows in order to purify NOx (nitrogen oxides) in the exhaust gas of the engine. The reducing agent is contained in the accommodating portion and is supplied to the injection portion. The reducing agent in the containment may freeze, for example, when the outside air temperature is low. When the reducing agent freezes, thawing control is performed to thaw the reducing agent.

Japanese Unexamined Patent Publication No. 2019-19794

By the way, until the thawing control is completed, the injection unit does not inject the reducing agent, and the water level of the reducing agent in the accommodating unit is not properly displayed. Therefore, the user of the exhaust gas purification system (vehicle driver) may misunderstand that the system is out of order.

Therefore, the present invention has been made in view of these points, and an object of the present invention is to prevent the user from misunderstanding that the system is out of order during the thawing control of the reducing agent.

In one aspect of the present invention, in an exhaust purification system that purifies the exhaust gas flowing through the exhaust pipe with a reducing agent, whether the accommodating portion accommodating the reducing agent and the reducing agent in the accommodating portion are frozen. A determination unit that determines whether or not the reducing agent is frozen, a thawing control unit that controls thawing to thaw the reducing agent when it is determined that the reducing agent is frozen, and the thawing control unit perform the thawing control. Provided is an exhaust gas purification system including a notification control unit for notifying that the defrosting control is in progress.

Further, the exhaust gas purification system further includes a water level detecting unit for detecting the water level of the reducing agent in the accommodating unit and a display unit for displaying water level information regarding the water level, and the notification control unit is used for defrosting control. The decompression information indicating that the inside may be displayed on the display unit.

Further, the notification control unit may display both the water level information and the defrosting information on the display unit.

Further, the notification control unit may display the defrosting information instead of the water level information displayed on the display unit.

Further, the thawing control unit performs thawing control for thawing the reducing agent using a heat source, and the notification control unit forcibly performs other control using the heat source by preferentially performing the thawing control. The information that has been stopped may also be notified.

According to the present invention, there is an effect that it is possible to prevent the user from misunderstanding that the system has failed during the defrosting control of the reducing agent.

It is a schematic diagram which shows the structure of the exhaust gas purification system S which concerns on one Embodiment. It is a schematic diagram for demonstrating the display example about urea water of a display part 80. It is a block diagram which shows the detailed structure of the control device 100. It is a schematic diagram for demonstrating the display example of the decompression information of the display part 80. It is a flowchart for demonstrating an example of the thawing process of urea water.

<Structure of exhaust purification system>
The configuration of the exhaust gas purification system S according to the embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a schematic view showing a configuration of an exhaust gas purification system S according to an embodiment. As shown in FIG. 1, the exhaust purification system S includes an engine 10, an exhaust passage 20, a DPF (Diesel Particulate Filter) 30, a urea water injection device 40, and an SCR (Selective Catalytic Reduction) device 50. , The NOx sensors 60 and 65, the display unit 80, and the control device 100. The exhaust gas purification system S is mounted on a vehicle such as a truck and purifies the exhaust gas of the engine 10.

The engine 10 is an internal combustion engine that generates power by burning and expanding a mixture of fuel and intake air (air). The engine 10 is a 4-cylinder diesel engine here, but the engine 10 is not limited to this, and may be an engine other than the 4-cylinder engine.

The exhaust passage 20 is an exhaust pipe connected to the engine 10 and exhausts the exhaust gas of the engine 10 to the outside of the vehicle. The exhaust passage 20 through which the exhaust gas flows is provided with a DPF 30, a urea water injection device 40, and an SCR device 50.

The DPF 30 is a filter that collects particulate matter (PM) contained in the exhaust gas. The DPF 30 is made of, for example, a honeycomb body made of metal or ceramics.

The urea water injection device 40 is provided between the DPF 30 and the SCR device 50, and injects urea water, which is an example of a reducing agent, into the exhaust passage 20. The urea water injected by the urea water injection device 40 is hydrolyzed by the heat of the exhaust gas flowing through the exhaust passage 20 to generate ammonia. Ammonia is used to cause a reduction reaction of NOx in the exhaust gas.

The urea water injection device 40 has an injection unit 41, a tank 42, a pump 43, and a flow path 44. The tank 42 is an accommodating portion for accommodating urea water. The pump 43 pumps the urea water in the tank 42 toward the injection unit 41. The flow path 44 is a supply path through which urea water sent to the injection section 41 by the pump 43 flows. The injection unit 41 injects urea water into the exhaust passage 20.

The SCR device 50 is a device that converts NOx in the exhaust gas into harmless nitrogen by a reduction reaction. The SCR device 50 has a reduction catalyst 52 that promotes a reduction reaction between ammonia and NOx. Ammonia generated from urea water is adsorbed on the reduction catalyst 52. The reduction catalyst 52 reduces NOx to nitrogen and water by adsorbed ammonia, and reduces NOx emissions.

The NOx sensors 60 and 65 detect the concentration of NOx in the exhaust gas. The NOx sensor 60 is provided on the upstream side of the SCR device 50 in the exhaust passage 20, and the NOx sensor 65 is provided on the downstream side of the SCR device 50. The NOx sensor 60 detects the concentration of NOx on the inlet side of the SCR device 50, and the NOx sensor 65 detects the concentration of NOx on the outlet side of the SCR device 50.

The display unit 80 displays various information regarding the state and operation of the exhaust gas purification system S.
FIG. 2 is a schematic view for explaining a display example of the display unit 80 regarding urea water. For example, as shown in FIG. 2A, the display unit 80 displays the water level information 82 (remaining amount level) regarding the water level of the urea water in the tank 42. Further, when the water level of the urea water in the tank 42 becomes lower than a predetermined value, the display unit 80 displays information prompting the replenishment of the urea water as shown in FIG. 2 (b).

The control device 100 controls the operation of the exhaust gas purification system S. In the present embodiment, the control device 100 controls the operation of the urea water injection device 40, the display unit 80, and the like.

The urea water in the tank 42 may freeze, for example, when the outside air temperature is low. When the urea water freezes, thawing control is usually performed to thaw the urea water using a heat source. By the way, until the thawing control of the urea water is completed, the injection unit 41 does not inject the urea water, and the water level of the urea water in the tank 42 is not properly displayed on the display unit 80. Therefore, the driver of the vehicle may misunderstand that the exhaust gas purification system S is out of order.
On the other hand, although the details of the control device 100 of the present embodiment will be described later, when the thawing control of the urea water in the tank 42 is performed, the thawing information indicating that the thawing control is in progress is displayed in the display unit 80. To display. As a result, for example, even if the water level of the urea water in the tank 42 is not properly displayed on the display unit 80, the driver can properly display the water level by looking at the defrosting information displayed on the display unit 80. It can be recognized that there is no such thing. As a result, it is possible to suppress the misunderstanding that the exhaust gas purification system S is out of order, and it is possible to prevent the vehicle from being repaired.

<Detailed configuration of control device>
An example of the detailed configuration of the control device 100 will be described with reference to FIG.
FIG. 3 is a block diagram showing a detailed configuration of the control device 100. The control device 100 has a storage unit 110 and a control unit 120.

The storage unit 110 includes, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage unit 110 stores programs and various data for execution by the control unit 120. For example, the storage unit 110 stores various information used for the thawing process of urea water, which will be described later.

The control unit 120 is, for example, a CPU (Central Processing Unit). The control unit 120 controls the operation of the exhaust gas purification system S by executing the program stored in the storage unit 110. In the present embodiment, the control unit 120 functions as a urea water information acquisition unit 122, a freeze determination unit 123, a thawing control unit 124, and a notification control unit 125.

The urea water information acquisition unit 122 acquires information on urea water. Specifically, the urea water information acquisition unit 122 acquires the detection information detected by the detector group 70. The detector group 70 includes, for example, a tank sensor 72 that detects the temperature and water level of urea water in the tank 42, an outside air temperature sensor 73 that detects the outside air temperature around the tank 42, and the like. The tank sensor 72 corresponds to a water level detection unit that detects the water level of urea water. The urea water information acquisition unit 122 outputs the acquired information to the freeze determination unit 123.

The freeze determination unit 123 determines whether or not the urea water is frozen. The freeze determination unit 123 determines whether or not the urea water in the tank 42 is frozen based on the information acquired by the urea water information acquisition unit 122. For example, the freeze determination unit 123 determines whether or not the urea water in the tank 42 is frozen based on the temperature of the urea water in the tank 42 and the ambient temperature outside the tank 42. The freeze determination unit 123 outputs the determination result to the thawing control unit 124.

The thawing control unit 124 performs thawing control to thaw the urea water when the urea water is frozen. When the freeze determination unit 123 determines that the urea water in the tank 42 is frozen, the thawing control unit 124 controls the thawing of the urea water.

The thawing control unit 124 controls the thawing of the urea water in the tank 42 using a heat source. The thawing control unit 124 controls the thawing of urea water using the cooling water of the engine 10 as a heat source. The cooling water of the engine 10 flows to the tank 42, and the urea water is thawed by the heat of the cooling water. However, the present invention is not limited to the above, and for example, the thawing control unit 124 may use a heater as a heat source to control the thawing of urea water.

The notification control unit 125 notifies the urea water. The notification control unit 125 notifies that the thawing control of the urea water is in progress when the thawing control unit 124 is performing the thawing control of the urea water. For example, the notification control unit 125 causes the display unit 80 to display thawing information indicating that the thawing control of urea water is in progress. When the thawing control of the urea water is completed, the notification control unit 125 ends the notification that the thawing control is in progress.

FIG. 4 is a schematic diagram for explaining a display example of decompression information of the display unit 80. As shown in FIG. 4, the notification control unit 125 may display both the water level information 82 and the defrosting information 84 on the display unit 80. In this case, by displaying the decompression information 84 on the display unit 80, the driver can recognize that the water level information 82 is not correct. The decompression information 84 is not limited to the character information shown in FIG. 4, and may be other character information as long as it can be easily understood by the driver.

Not limited to the above, the notification control unit 125 may display the defrosting information instead of the water level information displayed on the display unit 80. In this case, since the water level information that does not indicate the appropriate water level is not displayed, the driver can prevent the driver from misunderstanding the water level of the urea water. Further, the notification control unit 125 may output voice information to notify the display instead of the display on the display unit 80 or together with the display on the display unit 80.

The notification control unit 125 may also notify information that forcibly stops other control by giving priority to decompression control. For example, the notification control unit 125 may display on the display unit 80 that the idling stop is stopped when the defrosting control is performed. As a result, for example, in a vehicle that performs idling stop while stopped, the display unit 80 displays that the idling stop is not executed by the defrosting control. Even if the idling stop that should be performed is not performed, the driver can prevent the driver from misunderstanding that the vehicle is out of order.

<Urea water thawing process>
An operation example of the control device 100 during the thawing process of urea water will be described with reference to FIG.

FIG. 5 is a flowchart for explaining an example of the thawing process of urea water. The decompression process is performed by the control unit 120 executing the program stored in the storage unit 110.

First, the urea water information acquisition unit 122 acquires information on the urea water (step S102). For example, the urea water information acquisition unit 122 acquires information such as the temperature of the urea water in the tank 42 and the outside air temperature from the detector group 70.

Next, the freeze determination unit 123 determines whether or not the urea water in the tank 42 is frozen (step S104). That is, the freeze determination unit 123 determines whether or not the urea water in the tank 42 is frozen from the temperature of the urea water in the tank 42, the outside air temperature, and the like acquired by the urea water information acquisition unit 122.

Then, when it is determined in step S104 that the urea water in the tank 42 is frozen (Yes), the thawing control unit 124 performs thawing control for thawing the urea water in the tank 42 (step S106). .. When the defrosting control is being performed, the notification control unit 125 notifies that defrosting is in progress (step S108). For example, the notification control unit 125 causes the display unit 80 to display the decompression information shown in FIG. If the notification control unit 125 has a control that is stopped due to the defrosting control, the display unit 80 may display that the control is stopped.

The notification control unit 125 continues to notify that defrosting is in progress while the defrosting control is not completed (step S110: No). As a result, the driver can easily grasp that the defrosting control is being performed. On the other hand, when the thawing control is completed (step S110: Yes), the water level of the urea water in the tank 42 is appropriately displayed, so that the notification control unit 125 ends the notification that thawing is in progress (step S112). ..

<Effect in this embodiment>
The exhaust gas purification system S of the above-described embodiment performs thawing control for thawing the urea water when it is determined that the urea water in the tank 42 is frozen. Then, the exhaust gas purification system S notifies that the thawing control is in progress when the thawing control of the urea water is being performed. For example, the exhaust gas purification system S causes the display unit 80 to display defrosting information indicating that defrosting is in progress.
As a result, for example, even if the water level of urea water is not properly displayed on the display unit 80, the driver recognizes that the water level is not properly displayed by looking at the defrosting information displayed on the display unit 80. it can. As a result, it is possible to prevent the driver from misunderstanding that the exhaust gas purification system S is out of order.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes can be made within the scope of the gist thereof. is there. For example, all or a part of the device can be functionally or physically distributed / integrated in any unit. Also included in the embodiments of the present invention are new embodiments resulting from any combination of the plurality of embodiments. The effect of the new embodiment produced by the combination also has the effect of the original embodiment.

20 Exhaust passage 42 Tank 72 Tank sensor 80 Display unit 123 Freezing judgment unit 124 Thaw control unit 125 Notification control unit S Exhaust purification system

Claims (5)

An exhaust purification system that purifies the exhaust gas flowing through the exhaust pipe with a reducing agent.
The accommodating part accommodating the reducing agent and
A determination unit for determining whether or not the reducing agent in the storage unit is frozen, and a determination unit.
When it is determined that the reducing agent is frozen, a thawing control unit that controls thawing to thaw the reducing agent and a thawing control unit.
When the defrosting control unit is performing the defrosting control, a notification control unit that notifies that the defrosting control is in progress, and a notification control unit.
Equipped with an exhaust purification system. A water level detection unit that detects the water level of the reducing agent in the storage unit,
A display unit for displaying water level information related to the water level is further provided.
The notification control unit causes the display unit to display decompression information indicating that the decompression control is in progress.
The exhaust purification system according to claim 1. The notification control unit displays both the water level information and the defrosting information on the display unit.
The exhaust purification system according to claim 2. The notification control unit displays the defrosting information in place of the water level information displayed on the display unit.
The exhaust purification system according to claim 2. The thawing control unit performs thawing control for thawing the reducing agent using a heat source.
The notification control unit also notifies information that forcibly stops other control using the heat source by preferentially performing the defrosting control.
The exhaust gas purification system according to any one of claims 1 to 4.

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