JP4891857B2 - NOx purification device for internal combustion engine - Google Patents

Description

  The present invention relates to a NOx purification device for an internal combustion engine that is provided in an exhaust system of an internal combustion engine mounted on a hydraulic excavator or the like and includes a urea water tank.

  There exists a thing shown by patent document 1 as this type of prior art. In this prior art, a NOx purification device is provided in an exhaust system of an engine constituting an internal combustion engine of a vehicle. This NOx purification device uses a urea water tank and urea water supplied from the urea water tank as an engine. A urea water replenishing device for replenishing the exhaust system and an SCR catalyst.

The supply port of the urea water tank is formed so as to be connectable only to a specific supply nozzle. Thereby, it is possible to prevent erroneous replenishment of the liquid urea water tank other than the urea water.
JP 2003-278532 A

  The above-described conventional urea water tank has the following problems because its replenishing port can be coupled only with a specific replenishing nozzle. That is, when the urea water in the urea water tank is insufficient and needs to be replenished, the urea water cannot be replenished from the replenishing device having no specific replenishing nozzle described above. In addition, urea water cannot be replenished from a vehicle equipped with a urea water tank using, for example, a general pump. For this reason, it takes time to replenish the urea water to the urea water tank, and the replenishment of the urea water to the urea water tank is not in time, which may cause the urea water to run out. If such urea water shortage occurs, it will interfere with NOx purification in the exhaust system of the engine.

  The present invention has been made from the actual situation in the above-described prior art, and the object thereof is to prevent a replenishment of liquid other than urea water to the urea water tank and to require a replenishing device having a specific replenishing nozzle. Another object of the present invention is to provide a NOx purification device for an internal combustion engine that can easily replenish urea water to a urea water tank.

In order to achieve this object, the present invention provides a NOx purifying apparatus for an internal combustion engine provided with a urea water tank, a laboratory attached to the urea water tank and having an inlet, and urea water provided in the laboratory. and identification sensor, in accordance with the signal output from the urea water identification sensor, comprising a switching means for communicating or blocking between the laboratory and the urea water tank Rutotomoni, the urea water in the urea water tank A water level sensor for detecting the water level is provided, and the switching means is operated in accordance with a signal output from the water level sensor .

In the present invention configured as described above, when liquid is injected into the examination room from the injection port, the liquid is detected by the urea water identification sensor. When it is determined by the signal output from the urea water identification sensor that the liquid is urea water, the switching means is activated to connect the examination room and the urea water tank. As a result, the urea water injected into the examination room is guided to the urea water tank via the switching means, and the urea water is replenished to the urea water tank. Further, when it is determined by the signal output from the urea water identification sensor that the liquid is different from the urea water, the switching means is operated to shut off the examination room and the urea water tank. This prevents the liquid injected into the examination room from being mixed into the urea water tank. The injection port of the examination room may have any shape that can inject urea water. Therefore, the replenishing device that replenishes urea water to the urea water tank does not need to include a specific replenishing nozzle. That is, the present invention provides for the erroneous replenishment of liquids other than urea water to the urea water tank, the inspection room where the liquid is injected, the urea water identification sensor provided in the inspection room, and the communication between the inspection room and the urea water tank. -It can be prevented via the switching means to shut off, and urea water can be easily replenished to the urea water tank without requiring a replenishing device having a specific replenishing nozzle. In the present invention, the water level of the urea water in the urea water tank is, for example, a water level at which urea water may enter the examination room or a water level similar to the liquid level in the examination room. The switching means is actuated by a signal from the water level sensor that detects this, and the inspection room and the urea water tank are disconnected. As a result, it is possible to prevent the urea water in the urea water tank from flowing into the inspection chamber and prevent foreign matter floating on the surface of the liquid in the inspection chamber from entering the urea water tank.

  Further, the present invention is the above invention, wherein the switching means includes an opening for communicating the inspection chamber and the urea water tank, an operating body capable of opening and closing the opening, and an actuator for driving the operating body. It is characterized by including. In the present invention configured as described above, when it is determined that the liquid is urea water based on the signal output from the urea water identification sensor, the actuator is driven to operate the operating body so that the opening is opened. Is done. Thereby, the urea water injected into the examination room is supplied to the urea water tank through the opening. Further, when it is determined by the signal output from the urea water identification sensor that the liquid is different from the urea water, the actuator is driven to operate the operating body so that the opening is closed. Done. Thereby, an opening part is interrupted | blocked and mixing with the urea water tank of the liquid inject | poured into the test chamber is prevented.

  Further, the present invention is characterized in that, in the above-mentioned invention, the examination room has a discharge port for discharging the liquid injected into the examination room. According to the present invention configured as described above, when the liquid injected into the examination room is different from the urea water, the liquid can be discharged out of the examination room from the discharge port.

  Further, the present invention is characterized in that in the above-mentioned invention, an informing means operable according to a signal output from the urea water identification sensor is provided. In the present invention configured as described above, when it is determined by the signal output from the urea water identification sensor that the liquid injected into the examination room is different from the urea water, the notification means is activated and erroneous replenishment is performed. Can remind the resupplier that this is happening.

The present invention prevents erroneous supply of liquid other than urea water to the urea water tank, and easily supplies urea water to the urea water tank without requiring a replenishment device having a specific replenishment nozzle as in the prior art. Therefore, when the urea water tank needs to be replenished, it can be replenished in a relatively short time, and the urea water in the urea water tank can be prevented from running out. Thereby, the NOx purification performance superior to the conventional can be obtained. Further, the present invention can prevent the urea water in the urea water tank from flowing into the examination room and prevent foreign matters floating on the surface of the liquid in the examination room from entering the urea water tank. Thereby, a highly reliable NOx purification device is obtained.

  Hereinafter, the best mode for carrying out the NOx purification device for an internal combustion engine according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a main configuration of a first embodiment of a NOx purification device for an internal combustion engine according to the present invention, and FIG. 2 is a block diagram showing a signal processing system provided in the first embodiment shown in FIG.

  The NOx purification device according to the first embodiment is provided in, for example, a hydraulic excavator, and is disposed in an exhaust system of an engine that drives a hydraulic pump. The urea water tank 1 shown in FIG. And a urea water injection device (not shown) for supplying urea water in the urea water tank 1 to the exhaust gas passage of the engine, and a urea SCR catalyst (not shown) for reducing and purifying the exhaust gas to which the urea water is added.

  The urea water tank 1 shown in FIG. 1 provided in the first embodiment includes a supply port 1a to which a supply pipe 2 for supplying urea water to the above-described urea water injection device (not shown) is connected. Moreover, this 1st Embodiment is attached to the urea water tank 1, and has arrange | positioned the test | inspection chamber 3 which has the inlet 3a and the discharge port 3b in the urea water tank 1, for example. A discharge pipe 4 extending in the horizontal direction of the inspection chamber 3 and led out of the urea water tank 1 is connected to the discharge port 3 b of the inspection chamber 3. An opening / closing valve 5 for opening and closing the discharge pipe 4 is attached in the middle of the discharge pipe 4. In the inspection chamber 3, a urea water identification sensor 6 that detects, for example, the urea concentration of the liquid injected into the inspection chamber 3 from the injection port 3a and outputs a signal is disposed.

  The first embodiment also includes an opening 7 that allows the examination chamber 3 and the urea water tank 1 to communicate with each other, an operating body that can open and close the opening 7, such as an opening / closing plate 8, and an upper surface of the urea water tank 1, for example. And an actuator 9 for driving the opening / closing plate 8. When no control signal is given to the actuator 9, for example, as shown in FIG. 1, the opening / closing plate 8 is held so as to open the opening 7.

  Further, a water level sensor 10 for detecting the level of the urea water in the urea water tank 1 is provided, and the water level sensor 10 is configured so that the water level of the urea water in the urea water tank 1 is adjusted between the examination room 3 and the urea water tank 1, for example. When the water level corresponding to the lower end of the opening 7 to be communicated is reached, a signal is output. Further, on the upper surface of the urea water tank 1, for example, alarm means 12 for issuing an alarm, for example, an alarm is arranged.

  Furthermore, this 1st Embodiment is arrange | positioned at the upper surface of the urea water tank 1, for example, the signal output from the urea water identification sensor 6 and the signal output from the water level sensor 10 are input, and predetermined based on these signals And a controller 11 capable of outputting a signal corresponding to the determination result to the actuator 9 and the alarm device 12.

  The controller 11 receives a signal from the water level sensor 10 and a first determination unit that determines whether or not the liquid injected into the examination chamber 3 is urea water according to a signal output from the urea water identification sensor 6. Second discriminating means for discriminating whether or not the output has been made, and output means capable of outputting a control signal according to the discrimination results of the first and second discriminating means to the actuator 9 and outputting an operation signal to the alarm device 12 Including.

  The urea water identification sensor includes an opening 7 for communicating the inspection chamber 3 and the urea water tank 1 described above, an opening / closing plate 8 for opening / closing the opening 7, an actuator 9 for driving the opening / closing plate 8, and the like. In accordance with a signal output from 6, switching means for communicating or blocking between the examination room 3 and the urea water tank 1 is configured.

  In the first embodiment configured as described above, the urea water stored in the urea water tank 1 is sent from the supply port 1a shown in FIG. 1 to the urea water injection supply device (not shown) via the supply pipe 2. Urea water is injected from the water injection device into the exhaust gas passage of the engine, whereby the exhaust gas to which urea water has been added is reduced and purified by the urea SCR catalyst. Thereby, NOx in exhaust gas can be reduced.

  Note that while such a urea water supply operation is performed, the discharge pipe 4 connected to the discharge port 3 b of the examination chamber 3 is kept closed by the open / close valve 5.

  From this state, when the urea water in the urea water tank 1 is reduced and replenishment is required, replenishment is performed by a replenishing device (not shown) containing the urea water. At this time, the urea water of the replenishing device is replenished from the inlet 3 a of the examination room 3. When urea water is injected into the examination chamber 3, the urea water identification sensor 6 detects the urea concentration of the injected liquid, that is, urea water, and outputs a detection signal to the controller 11. The first determination unit of the controller 11 determines whether the liquid injected into the examination chamber 3 is urea water based on a signal output from the urea water identification sensor 6. In this case, since it is determined to be urea water, a control signal or an operation signal is not output from the output means of the controller 11 to the actuator 9 and the alarm device 12.

  When urea water is continuously supplied to the urea water tank 1 and the water level in the urea water tank 1 becomes high and the water level sensor 10 is activated, a signal is output from the water level sensor to the controller 11. The second determination means of the controller 11 determines whether or not a signal is output from the water level sensor 10, but in this case, it is determined that a signal is output from the water level sensor 10, and the controller 11 determines whether or not the signal is output. A control signal is output from the output means to the actuator 9, and an operation signal is output to the alarm device 12. As a result, the actuator 9 is driven, the opening / closing plate 8 is rotated so as to close the opening 7, and the inspection chamber 3 and the urea water tank 1 are disconnected. Therefore, invasion of urea water from the urea water tank 1 to the inspection chamber 3 and entry of foreign matter such as urea water from the inspection chamber 3 to the urea water tank 1 and oil floating on the surface of the liquid are prevented. . At the same time, the alarm device 12 issues an alarm, thereby making it possible for the supplier to notice that the urea water supply to the urea water tank 1 has been completed.

  Further, when the remaining amount of urea water in the urea water tank 1 is reduced and the liquid is replenished, if the liquid is a liquid different from the urea water, for example, water, fuel, hydraulic oil, etc., The urea concentration of the liquid is detected by the urea water identification sensor 6 and a detection signal is output to the controller 11. The first determination unit of the controller 11 determines whether the liquid injected into the examination chamber 3 is urea water based on the signal output from the urea water identification sensor 6. In this case, it is determined that the aqueous solution is not urea water, and a control signal is output from the output means of the controller 11 to the actuator 9 according to the determination result, and an operation signal is output to the alarm device 12. As a result, the actuator 9 is driven, the opening / closing plate 8 is rotated so as to close the opening 7, and the inspection chamber 3 and the urea water tank 1 are disconnected. Therefore, mixing of the liquid different from the urea water from the inspection chamber 3 to the urea water tank 1 is prevented. At the same time, the alarm device 12 issues an alarm, thereby making it possible for the replenisher to be aware that the urea water tank 1 is about to be replenished with a liquid different from urea water, that is, erroneous replenishment is being performed. .

  The replenisher who notices such an erroneous replenishment immediately stops the erroneous replenishment of the liquid other than the urea water and operates the open / close valve 5 of the exhaust pipe 4 connected to the examination room 3, for example, to open the exhaust pipe 4. Perform the operation. As a result, the liquid injected into the examination chamber 3 is guided from the discharge port 3b of the examination chamber 3 to the discharge pipe 4, and is discharged to the outside through the discharge pipe 4. Thereafter, the replenisher only needs to replenish the urea water from the inlet 3a of the examination room 3 with a regular replenishing device in which the urea water is accommodated. In this way, the urea water tank 1 can be replenished with the required amount of urea water as described above.

  According to the NOx purification device for an internal combustion engine according to the first embodiment configured as described above, an error of the liquid injected into the examination chamber 3 into the urea water tank 1 is detected by a signal output from the urea water identification sensor 6. Replenishment can be prevented, and the injection port 3a of the examination room 3 only needs to have a shape capable of injecting urea water. Therefore, the replenishing device for replenishing urea water to the urea water tank 1 includes a specific replenishing nozzle. There is no need to be. That is, in the first embodiment, an erroneous replenishment of liquid other than urea water to the urea water tank 1 is performed in the inspection chamber 3 into which the liquid is injected, the urea water identification sensor 6 provided in the inspection chamber 3, and the inspection. It can be prevented via an operating means including an opening / closing plate 8 or the like for communicating / blocking between the chamber 3 and the urea water tank 1, and the urea water tank 1 can be easily connected to the urea water tank 1 without requiring a replenishing device having a specific replenishing nozzle. Can supply water. Therefore, when the urea water tank 1 needs to be replenished, it can be replenished in a relatively short time, and the urea water in the urea water tank 1 can be prevented from running out. Thereby, the outstanding NOx purification performance is securable.

  The first embodiment also includes a water level sensor 10 that detects the level of urea water in the urea water tank 1, and operates switching means including an opening / closing plate 8 and the like in accordance with a signal output from the water level sensor 10. Therefore, the water level of the urea water in the urea water tank 1 seems to be, for example, a water level at which urea water may enter the inspection chamber 3 or a water level similar to the liquid level in the inspection chamber 3. In such a case, the switching means including the opening / closing plate 8 and the like is actuated by a signal from the water level sensor 10 that detects this, and the inspection chamber 3 and the urea water tank 1 are disconnected. As a result, urea water in the urea water tank 1 can flow into the inspection chamber 3, and foreign matter floating on the surface of the liquid in the inspection chamber 3 can be prevented from entering the urea water tank 1 side. A high NOx purification device can be obtained.

  In addition, the first embodiment is provided with a notification means that can be operated in accordance with a signal output from the urea water identification sensor 6 and can be operated in accordance with a signal output from the water level sensor 10, for example, an alarm device 12. Therefore, when the liquid injected into the examination room 3 is a liquid different from the urea water and erroneous replenishment is to be performed, or when the urea water replenishment into the urea water tank 1 is completed. These can be noticed to the replenisher by the alarm of the alarm device 12. Note that the notification means is not limited to the alarm device 12, and an alarm lamp, a sound generator, or the like can be provided.

  FIG. 3 is a diagram showing a main configuration of the second embodiment of the present invention. In the second embodiment, the inspection chamber 3 is provided outside the urea water tank 1, and the inspection chamber 3 and the urea water tank 1 are communicated with each other by a communication pipe 13. Switching means for communicating between the examination chamber 3 and the urea water tank 1 is provided at a connection portion between the communication pipe 13 and the urea water tank 1. That is, an opening 7 included in the switching means is formed at a connection portion between the communication pipe 13 and the urea water tank 1, and an operating body that opens and closes the opening 7, for example, an opening / closing plate 8, is driven. An actuator 9 is provided on the upper surface side portion of the urea water tank 1. The water level sensor 10 is disposed, for example, in the urea water tank 1 and is provided near the lower end of the opening 7. In the first embodiment, the drain pipe 4 extends from the examination room 3 in the horizontal direction. In the second embodiment, the drain pipe 4 extends from the examination room 3 downward. Other configurations are the same as those of the first embodiment.

  In the second embodiment configured as described above, when the water level sensor 10 is activated, or when the urea water in the urea water tank 1 is reduced and the liquid is replenished, the liquid is different from the urea water. For example, when the urea water identification sensor 6 detects water, fuel, hydraulic oil, or the like, a control signal is output from the output means of the controller 11 to the actuator 9 as in the first embodiment, and An operation signal is output to the alarm device 12, and the same effect as in the first embodiment can be obtained.

  In particular, in the second embodiment, since the inspection chamber 3 is disposed outside the urea water tank 1, the capacity of the urea water tank 1 can be secured large, and a relatively large amount of urea water can be removed. It can be accommodated in the water tank 1, and NOx reduction efficiency can be improved.

It is a figure showing the important section composition of a 1st embodiment of the NOx purification device of an internal-combustion engine concerning the present invention. It is a block diagram which shows the signal processing system with which 1st Embodiment shown in FIG. 1 is equipped. It is a figure which shows the principal part structure of 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Urea water tank 1a Supply port 2 Supply pipe 3 Inspection room 3a Inlet 3b Discharge port 4 Discharge pipe 5 Opening / closing valve 6 Urea water identification sensor 7 Opening part (switching means)
8 Opening and closing plate (actuator) [switching means]
9 Actuator (switching means)
10 Water level sensor 11 Controller 12 Alarm (notification means)
13 Communication pipe

Claims (4)

In an internal combustion engine NOx purification device equipped with a urea water tank,
An inspection room attached to the urea water tank and having an inlet, a urea water identification sensor provided in the inspection room, and the inspection room and the urea water tank according to a signal output from the urea water identification sensor Rutotomoni comprising a switching means for communicating or blocking between,
A NOx purification device for an internal combustion engine, comprising: a water level sensor for detecting the level of urea water in the urea water tank; and operating the switching means in accordance with a signal output from the water level sensor . In the invention of claim 1,
The switching means includes an opening for communicating the inspection chamber and the urea water tank, an operating body capable of opening and closing the opening, and an actuator for driving the operating body. NOx purification device. In the invention of claim 1,
A NOx purification device for an internal combustion engine, wherein the inspection chamber has a discharge port for discharging the liquid injected into the inspection chamber. In the invention of claim 1,
A NOx purification device for an internal combustion engine, comprising a notification means operable in response to a signal output from the urea water identification sensor .

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