JP2010127078A - Urea tank system, urea replenishing method and injector cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a urea tank system having a high degree of freedom of arrangement without requiring a space for laying an inlet pipe, a urea replenishing method for replenishing urea to a urea tank of this urea tank system, and an injector cleaning method for cleaning an injector of the urea tank system. <P>SOLUTION: A urea pump 16 can switch normal driving for discharging the urea in the urea tank 14 to an external part and reverse driving for sucking the urea in the urea tank 14 from the external part. The urea pump 16 is connected with the other end of a urea replenishing pipe 26. When reversely driving the urea pump 16, the urea in a urea bottle 30 is replenished in the urea tank 14 via the urea replenishing tank 26. Since the inlet pipe is not required, a space for laying is not required. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a urea tank system, a urea replenishing method for replenishing urea to the urea tank of the urea tank system, and an injector cleaning method for cleaning an injector of the urea tank system.

  Urea is supplied to a SCR catalyst for purifying exhaust gas from a diesel engine from a urea tank system including a urea tank. For example, Patent Document 1 describes a structure (reducing agent supply device) including a urea water tank. Generally, a lower end portion of an inlet pipe is connected to the urea tank in order to supply urea to the urea tank.

However, in a structure in which the urea tank is disposed at a low position in the engine room of the vehicle body, if the upper end of the inlet pipe (urea inlet) is set at a high position in consideration of workability during replenishment, the length of the inlet pipe is reduced. It can be long and difficult to route. In particular, since the inlet pipe needs a predetermined inner diameter to allow urea to flow down, a large space is required for wiring. For this reason, the freedom degree of arrangement | positioning of a urea tank system also becomes low.
JP 2006-9606

  In consideration of the above facts, the present invention eliminates the need for space for inlet pipe routing, a urea tank system having a high degree of freedom in arrangement, and a urea replenishing method for replenishing the urea tank of this urea tank system, and It is an object to obtain an injector cleaning method for cleaning an injector of a urea tank system.

  According to the first aspect of the present invention, a urea tank capable of containing urea, an injector for injecting urea, and urea from the first supply / discharge port on the urea tank side to the second supply / discharge port on the injector side And a urea pump capable of switching between movement of the urea from the second supply / discharge port to the first supply / discharge port, one end serving as a supply port for replenishing urea, and the other end serving as the urea And a urea supply pipe communicated with the second supply / exhaust port of the pump.

  In this urea tank system, the urea pump can switch between urea movement (forward drive) from the first supply / discharge port to the second supply / discharge port and urea movement (reverse drive) in the opposite direction. . For example, urea can be supplied from the urea tank to the injector by moving urea from the first supply / discharge port to the second supply / discharge port. The urea pump is connected to the other end of the urea supply pipe. Therefore, urea can be replenished to the urea tank by immersing one end of the fuel supply pipe in, for example, urea in an external urea storage member, and reversely driving the urea pump to perform urea suction.

  As described above, in the present invention, urea is supplied to the urea tank by the urea supply pipe, so that the conventional inlet pipe is unnecessary and the wiring space is not required. Since urea can be positively replenished to the urea tank using the urea pump, the diameter of the urea replenishment pipe can be made smaller than that of the inlet pipe that allows natural flow of urea. By these, the freedom degree of arrangement | positioning of a urea tank system becomes high.

  According to a second aspect of the present invention, in the first aspect of the present invention, one end is connected to the injector and the other end is connected to the second supply / exhaust port of the urea pump, and the urea pump is driven to send urea to the injector. A urea supply pipe, and the urea supply pipe is connected to the urea supply pipe.

  That is, in the invention according to claim 1, the other end of the urea supply pipe may be directly connected to the urea pump, but the urea supply pipe is connected to the urea supply pipe, and the urea supply pipe is connected via the urea supply pipe. The structure connected to the 2nd supply / exhaust port of a pump may be sufficient.

  As a result, compared to a structure in which the other end of the urea supply pipe is connected to the urea pump separately from the urea supply pipe, the substantial length of the urea supply pipe is shortened, so the degree of freedom in the arrangement of the urea tank system is reduced. It gets even higher.

  According to a third aspect of the present invention, a urea tank capable of containing urea, an injector for injecting urea, and urea from the first supply / discharge port on the urea tank side to the second supply / discharge port on the injector side And a urea pump capable of switching between movement of the urea from the second supply / discharge port to the first supply / discharge port, one end serving as a supply port for replenishing urea, and the other end serving as the urea A urea supply method for replenishing urea from an external urea storage member to the urea tank of a urea tank system having a urea supply pipe communicated with the second supply / discharge port of the pump, wherein the urea supply pipe One end of the urea storage member is communicated with the urea storage member, and the urea pump is driven to suck urea from the urea storage member into the urea tank.

  In this urea supply method, one end of the urea supply pipe is communicated with the urea storage member. The communication here includes, for example, immersing one end of the urea supply pipe in the stored urea when urea is stored in the urea storage member. Moreover, when the front-end | tip of a urea storage member is formed in the cylinder shape, connecting the end of a urea supply pipe | tube to this cylindrical part is also included.

  By driving the urea pump in a state where one end of the urea supply pipe communicates with the urea storage member in this way, urea can be sucked from the urea storage member through the urea supply pipe and supplied to the urea tank.

  According to a fourth aspect of the present invention, a urea tank capable of containing urea, an injector for injecting urea, and urea from the first supply / discharge port on the urea tank side to the second supply / discharge port on the injector side And a urea pump capable of switching between movement of the urea from the second supply / discharge port to the first supply / discharge port, one end serving as a supply port for replenishing urea, and the other end serving as the urea A urea supply pipe communicated with the second supply / exhaust port of the pump, and one end connected to the injector and the other end connected to the second supply / exhaust port of the urea pump for driving urea to the injector by driving the urea pump A method for cleaning an injector of a urea tank system having a urea supply pipe, wherein the urea supply pipe is connected to the urea supply pipe, wherein one end of the urea supply pipe is supplied with high-pressure air Possible air supply Connected to a member, it is discharged from the injector to send a high pressure air supplied from the air supply member to the injector.

  In this injector cleaning method, one end of the urea supply pipe is connected to an air supply member, and high-pressure air supplied from the air supply member is sent to the injector. In the injector, internal deposits and the like are removed by discharging high-pressure air. Thus, in the present invention, the inside of the injector can be effectively cleaned.

  Since the present invention is configured as described above, a space for inlet pipe routing is unnecessary, a urea tank system having a high degree of freedom in arrangement, a urea replenishing method for replenishing urea to the urea tank of this urea tank system, and An injector cleaning method for cleaning the injector of the urea tank system is obtained.

  1 and 2 show a schematic configuration of the urea tank system 12 according to the first embodiment of the present invention. The urea tank system 12 has a urea tank 14 that can store urea. A urea pump 16 is provided on the upper surface of the urea tank 14, and a first supply / exhaust port 16 </ b> A located near the lower surface of the urea tank 14 is provided below the urea pump 16. A second supply / discharge port 16B located above the urea tank 14 is provided. The urea pump 16 takes the urea in the urea tank 14 from the first supply / discharge port 16A and discharges the urea from the second supply / discharge port 16B to the outside, and takes urea from the outside through the second supply / discharge port 16B. Switching between reverse driving for sucking urea into the urea tank 14 from the one supply / discharge port 16A can be performed. In the present embodiment, a diaphragm pump is used as the urea pump 16 so as to prevent the fluid from flowing into the urea tank 14 when not driven.

  The lower end of the urea supply pipe 18 is connected to the second supply / discharge port 16B of the urea tank 14. The upper end of the urea supply pipe 18 is connected to an injector 20 capable of injecting urea. An SCR catalyst 24 is provided in an exhaust pipe 22 for discharging gas from an engine (not shown), and urea is injected from the injector 20 to the SCR catalyst 24. Thereby, in the SCR catalyst 24, the nitrogen oxide in the exhaust gas sent from the engine through the exhaust pipe 22 chemically reacts with the ammonia and is purified.

  The injector 20 has an injection cutoff valve capable of switching between an open state in which the urea flow is allowed to flow from the urea supply pipe 18 to the SCR catalyst 24 and the degree of urine is injected and a cutoff state in which the urea flow can be blocked. ing.

  Further, the other end of the urea supply pipe 26 is connected to the second supply / discharge port 16 </ b> B of the urea pump 16. One end of the urea replenishing pipe 26 is a replenishing port 28, and has a structure that can be immersed in urea in a urea bottle 30 in which urea is stored in advance. In the replenishing port 28, an on-off valve 32 capable of blocking the internal urea flow is provided.

  The urea pump 16 is driven and controlled by the ECU 36 that has received a signal from the changeover switch 34. In addition, the injector 20 (injection cutoff valve) and the opening / closing valve 32 in the replenishing port 28 are also controlled by the ECU 36. Note that the changeover switch 34 is in an injection state in which urea in the urea tank 14 is sent to the injector 20 for injection, a replenishment state in which urea is supplied to the urea tank 14, and urea in the urea tank 14 is discharged to remove urea. It is possible to selectively switch at least three states of a discharge state in which replacement or the like can be performed.

  Next, the operation of the urea tank system 12 of the present embodiment and a method for supplying urea to the urea tank 14 of the urea tank system 12 will be described.

  In this urea tank system 12, when the changeover switch 34 is in the injection state, the ECU 36 opens the injector 20 (injection cutoff valve), closes the on-off valve 32 in the replenishing port 28, and drives the urea pump 16 forward. . As a result, the urea in the urea tank 14 is sent to the injector 20 through the urea supply pipe 18 as indicated by an arrow F1 in FIG. Then, urea is injected from the injector 20 into the SCR catalyst 24, whereby the SCR catalyst 24 purifies nitrogen oxides in the exhaust gas sent from the engine through the exhaust pipe 22. At this time, since the on-off valve 32 in the supply port 28 is closed, urea is not inadvertently discharged from the supply port 28.

  When urea is supplied to the urea tank 14, as shown in FIG. 2, a urea storage member such as a urea bottle 30 in which urea is stored in advance is prepared, and the supply port 28 at one end of the urea supply pipe 26 is connected to the urea bottle 30. Immerse in the urea inside. Further, the changeover switch 34 is set to the replenishment state. The ECU 36 shuts off the injector 20 (injection shutoff valve), opens the on-off valve 32 in the replenishing port 28, and reversely drives the urea pump 16. As a result, the urea in the urea bottle 30 is supplied into the urea tank 14 through the urea supply pipe 26 as indicated by an arrow F2 in FIG.

  As described above, in the urea tank system 12 of the present embodiment, the urea pump 16 is reversely driven, so that urea is actively sucked from the urea storage member such as the urea bottle 30 and the urea tank 14 is replenished with urea. It can be performed. This eliminates the need for an inlet pipe for supplying urea to the urea tank 14 and a breather pipe attached to the inlet pipe.

  Further, in the conventional structure in which urea is supplied to the urea tank 14 using an inlet pipe, a predetermined inner diameter is required for the inlet pipe to let the urea flow down naturally. In the present embodiment, the urea pump is used as described above. Since urea is actively sucked and replenished by 16, the inner diameter of the urea supply pipe 26 can be made smaller than the inner diameter of the inlet pipe.

  As can be seen from the above, in this embodiment, an inlet pipe or the like for supplying urea to the urea tank 14 is unnecessary, and a space for arranging the inlet pipe is also unnecessary. Moreover, the urea supply pipe 26 that is thinner than the inlet pipe can also be used. For this reason, the freedom degree of arrangement | positioning of the urea tank system 12 to a vehicle body becomes high, and mounting design becomes easy. Further, since no inlet pipe is used, the urea tank system 12 can be configured at low cost.

  In the urea tank system 12 of the present embodiment, the urea in the urea tank 14 can be discharged to the outside using the urea supply pipe 26. In this case, the changeover switch 34 is set to the discharge state. The ECU 36 shuts off the injector 20 (injection shutoff valve), opens the on-off valve 32 in the replenishing port 28, and drives the urea pump 16 forward. As a result, urea in the urea tank 14 is discharged to the outside of the urea tank 14 through the urea supply pipe 26. Thereafter, if urea is replenished to the urea tank 14 as necessary, the urea in the urea tank 14 is eventually replaced. Since the urea in the urea tank 14 is discharged using the urea pump 16, it is not necessary to provide a drain pipe for discharging urea at the bottom of the urea tank 14, and the structure can be simplified.

  Further, when the urea in the urea tank 14 is discharged to the outside as described above, the urea supply pipe 26 can be internally cleaned with the urea flowing in the urea supply pipe 26.

  3 to 5 show a urea tank system 52 according to a second embodiment of the present invention. In the second embodiment, the connection structure on the other end side of the urea supply pipe 56 is different from that of the first embodiment, but the other configuration is the same as that of the first embodiment. Hereinafter, only points different from the first will be described, the same components, members, and the like will be denoted by the same reference numerals, and detailed description thereof will be omitted.

  The other end side of the urea supply pipe 56 of the second embodiment is a connection part 56C, and is connected to the upper part of the urea supply pipe 18 (near the injector 20) by this connection part 56C. In other words, in the portion closer to the urea pump 16 than the connection portion 56C, the other end side portion of the urea supply pipe 18 also serves as the other end side portion of the urea supply pipe 56, and the combined portion 58 is configured. Yes. That is, the other end of the urea supply pipe 56 communicates with the urea pump 16 via a part of the urea supply pipe 18 that is the dual-purpose part 56. For this reason, the urea supply pipe 56 of the second embodiment is generally shorter than the urea supply pipe 26 of the first embodiment by the combined portion 58.

  Also in the urea tank system 52 of the second embodiment configured as described above, as in the urea tank system 12 of the first embodiment, the changeover switch 34 is set to the injection state, and as shown in FIG. The urea inside can be injected from the injector 20. Further, when the changeover switch 34 is in the replenishment state, it can be replenished from a urea reservoir member such as the urea bottle 30 as shown in FIG. Furthermore, if the changeover switch 34 is set in the discharge state, urea can be discharged from the urea tank 14 to the outside. Particularly in the second embodiment, when urea is discharged, not only the urea supply pipe 56 but also the dual-purpose part 58, that is, a part of the urea supply pipe 18, flows. Internal cleaning of the part is also possible.

  Also in the second embodiment, an inlet pipe or the like for supplying urea to the urea tank 14 is unnecessary, and a wiring space is also unnecessary. In addition, as the urea supply pipe 56, a pipe thinner than the inlet pipe can be used. For this reason, the degree of freedom of arrangement of the urea tank system 12 on the vehicle body is increased, and the urea tank system 52 can be configured at low cost.

  In particular, in the urea tank system 52 of the second embodiment, as described above, the length of the urea supply pipe 56 is shorter than that of the urea supply pipe 26 of the first embodiment. Therefore, the degree of freedom for mounting the urea tank system 52 on the vehicle body is higher than in the first embodiment, and the mounting design is facilitated. Moreover, since the urea supply pipe 56 is short, the urea tank system 12 can be configured at a lower cost.

  Furthermore, in the second embodiment, the inside of the injector 20 can be cleaned. That is, the injector 20 (injection shutoff valve) is opened, the on-off valve 32 in the replenishing port 28 is opened, and a high pressure gas supply device such as a compressor 62 is connected to the replenishing port 28 as shown in FIG. . When the high pressure gas is supplied from the compressor 62 to the replenishing port 28, the high pressure gas is discharged from the injector 20 through the urea replenishment pipe 26 through the upper portion of the urea supply pipe 18, as shown by an arrow F3 in FIG. For example, when deposits such as soot are accumulated in the injector 20, the deposits are removed by the discharge of the pressure gas, so that the operation stability of the injector 20 can be maintained high.

  The injector 20 (injection shut-off valve) may be opened before the high pressure gas is supplied from the compressor 62, but the compressor 62 is operated for a predetermined time to be connected to the inlet side (the urea supply pipe 56 side) of the injector 20. It is more preferable to open the injector 20 (injection shutoff valve) after giving an air pressure difference to the outlet side (SCR catalyst 24 side), because the inside of the injector 20 can be cleaned more effectively. In this case, the ECU 36 can control the opening timing of the injector 20 (injection cutoff valve) and the like.

  Further, the replenishing port 28 can be connected to the tip of the high-pressure gas supply pipe 64 of the compressor 62 in consideration of the connectivity with the compressor 62 (for example, having a predetermined-shaped attachment or screw-in structure). It is preferable that

  In the second embodiment, the structure in which the urea supply pipe 56 is connected to the upper part of the urea supply pipe 18 is described above. However, the urea supply pipe 18 may be connected to the middle part or the lower part of the urea supply pipe 18. Even if it connects in any location, since it becomes unnecessary to connect the urea supply pipe | tube 58 directly to the urea pump 16, a structure can be simplified and the freedom degree of mounting to a vehicle body can be raised. However, the closer the connection location is to the urea pump 16, the shorter the combined portion 58 and the longer the urea supply pipe 56. Therefore, from the viewpoint of shortening the substantial length of the urea supply pipe 56 and increasing the degree of freedom of mounting on the vehicle body, the merging position is preferably closer to the injector 20.

  Moreover, even when internal cleaning of the combined portion 58 of the urea replenishment pipe 58 and the urea supply pipe 18 is performed by discharging urea from the urea tank 14, the portion of urea that can be actually cleaned as the connection location approaches the urea pump 16. This is preferable because the length of the supply pipe 18 (the combined portion 58) becomes longer.

  In each of the above embodiments, an example in which the replenishing port 28 at one end of the urea replenishing pipes 26 and 56 is provided with the on-off valve 32 is used. In short, urea (fluid) is contained inside the urea replenishing pipe 26. If the flow can be allowed or blocked, it is not necessary to provide the replenishment port 28. For example, the opening / closing valve 32 may be provided in the middle part of the urea supply pipes 26, 56, and in the first embodiment, the urea pump 16 may have the function of the opening / closing valve.

It is the schematic which shows the urea tank system of 1st Embodiment of this invention in the urea ejection state from an injector. It is the schematic which shows the urea tank system of 1st Embodiment of this invention in the urea replenishment state to a urea tank. It is the schematic which shows the urea tank system of 2nd Embodiment of this invention in the urea ejection state from an injector. It is the schematic which shows the urea tank system of 2nd Embodiment of this invention in the urea replenishment state to a urea tank. It is the schematic which shows the urea tank system of 2nd Embodiment of this invention in the cleaning state of an injector.

Explanation of symbols

12 urea tank system 14 urea tank 16 urea pump 16A first supply / discharge port 16B second supply / discharge port 18 urea supply pipe 18 urea supply pipe 20 injector 22 exhaust pipe 24 SCR catalyst 26 urea supply pipe 28 supply port 30 urea bottle 32 open / close Valve 34 Changeover switch 52 Urea tank system 56 Urea supply pipe 58 Combined part 62 Compressor 64 High pressure gas supply pipe

Claims (4)

A urea tank capable of containing urea;
An injector for injecting urea;
It is possible to switch between the movement of urea from the first supply / discharge port on the urea tank side to the second supply / discharge port on the injector side and the movement of urea from the second supply / discharge port to the first supply / discharge port. A urea pump,
A urea supply pipe having one end as a supply port for supplying urea and the other end communicated with the second supply / discharge port of the urea pump;
Urea tank system with A urea supply pipe, one end of which is connected to the injector and the other end is connected to the second supply / exhaust port of the urea pump, and urea is driven to the injector by driving the urea pump;
Have
The urea tank system according to claim 1, wherein the urea supply pipe is connected to the urea supply pipe. A urea tank capable of containing urea;
An injector for injecting urea;
It is possible to switch between the movement of urea from the first supply / discharge port on the urea tank side to the second supply / discharge port on the injector side and the movement of urea from the second supply / discharge port to the first supply / discharge port. A urea pump,
A urea supply pipe having one end as a supply port for supplying urea and the other end communicated with the second supply / discharge port of the urea pump;
A urea replenishing method for replenishing urea from an external urea storage member to the urea tank of a urea tank system having
One end of the urea supply pipe communicates with the urea storage member,
A urea replenishing method in which the urea pump is driven to suck urea from the urea storage member into the urea tank. A urea tank capable of containing urea;
An injector for injecting urea;
It is possible to switch between the movement of urea from the first supply / discharge port on the urea tank side to the second supply / discharge port on the injector side and the movement of urea from the second supply / discharge port to the first supply / discharge port. A urea pump,
A urea supply pipe having one end as a supply port for supplying urea and the other end communicated with the second supply / discharge port of the urea pump;
A urea supply pipe, one end of which is connected to the injector and the other end is connected to the second supply / exhaust port of the urea pump, and urea is driven to the injector by driving the urea pump;
Have
An injector cleaning method for cleaning the injector of a urea tank system in which the urea supply pipe is connected to the urea supply pipe,
One end of the urea supply pipe is connected to an air supply member capable of supplying high-pressure air,
An injector cleaning method in which high-pressure air supplied from the air supply member is sent to the injector and discharged from the injector.

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