JP6930211B2 - Reducing agent injection valve - Google Patents

Description

The disclosure herein relates to a reducing agent injection valve that injects a reducing agent.

Patent Document 1 discloses an injection valve that injects urea water into the upstream side of the purification device in the exhaust flow path of the internal combustion engine. Then, on the reduction catalyst of the purification device, ammonia generated from urea water acts as a reducing agent to reduce and purify NOx in the exhaust gas.

Japanese Unexamined Patent Publication No. 2014-238016

By the way, in recent years, it has become desired to arrange the purification device close to the combustion chamber of the internal combustion engine in order to shorten the catalyst warm-up period at the time of cold start. Then, the distance between the injection valve and the purification device may have to be shortened. In that case, the spray from the injection valve is wide-angled so that the urea water is uniformly sprayed on the exhaust inflow surface of the purification device. Is required.

One object disclosed is to provide a reducing agent injection valve with a wide angle of spraying of the reducing agent.

The reducing agent injection valve disclosed here includes a injection hole (51) for injecting a reducing agent, a supply flow path (30F) for supplying the reducing agent to the injection hole, and a valve body (32) for opening and closing the supply flow path. A reducing agent injection valve that injects a reducing agent onto the upstream side of the purification device (20) in the exhaust passage (11a) of the internal combustion engine (10).
The supply flow path includes a first flow path portion (43) that causes the reducing agent that has flowed in from one end side and the reducing agent that has flowed in from the other end side to collide with each other, and the reducing agent that has flowed in from one end side and the reducing agent that has flowed in from the other end side. A second flow path portion (44) that collides with the agent, a first flow section (53) that communicates with the first flow path portion and circulates the reducing agent that collides with the first flow path portion, and a second flow path. The second distribution unit (54), which communicates with the unit and distributes the reducing agent that collided in the second flow path unit, and the reducing agent distributed through the first distribution unit and the reducing agent distributed through the second distribution unit are merged. , merging section to guide the merged reducing agent to the injection hole (55), and have a,
The first flow section and the second flow section extend radially from the confluence portion extending along the central axis (C) of the valve body toward opposite sides via the central axis .

According to the reducing agent injection valve disclosed here, the reducing agents collide with each other (pre-collision) in each of the first flow path portion and the second flow path portion, and the pre-collision reducing agents further collide with each other at the confluence portion. It will collide. In this way, since the pre-collision is performed in the flow path portion before the collision at the confluence portion, the turbulent energy of the urea water can be increased by the amount of the pre-collision. The larger the turbulent energy, the greater the force that tries to expand the volume, so that the reducing agent can be guided to the injection hole in a state where the volume expansion tendency is strong. Therefore, according to the reducing agent injection valve, the reducing agent injected from the injection hole can be sprayed in a greatly expanded state, and the spraying of the reducing agent can be widened.

The disclosed aspects herein employ different technical means to achieve their respective objectives. The claims and the reference numerals in parentheses described in this section exemplify the correspondence with the parts of the embodiments described later, and are not intended to limit the technical scope. The objectives, features, and effects disclosed herein will be made clearer by reference to the subsequent detailed description and accompanying drawings.

The schematic diagram which shows the state which the reducing agent injection valve which concerns on 1st Embodiment is attached to an exhaust pipe. The figure which shows the simple substance state of the reducing agent injection valve shown in FIG. FIG. 2 is a cross-sectional view of the reducing agent injection valve shown in FIG. Enlarged view of FIG. The exploded perspective view of FIG. FIG. 5 is a view taken along the line VI of FIG. The figure which shows the reducing agent injection valve which concerns on the comparative example of 1st Embodiment. The figure which shows the result of simulating the turbulent energy distribution of urea water. The figure which shows the relationship between the depth dimension of a supply flow path and turbulent flow energy. The figure which shows the relationship between the width dimension of a supply flow path and turbulent flow energy.

Hereinafter, a plurality of embodiments will be described with reference to the drawings. In each form, the same reference numerals may be given to the parts corresponding to the matters described in the preceding forms, and duplicate explanations may be omitted. In each form, when only a part of the configuration is described, the other parts of the configuration can be applied with reference to the other forms described above.

(First Embodiment)
The internal combustion engine 10 shown in FIG. 1 is mounted on a vehicle and functions as a traveling drive source. The exhaust gas discharged from the combustion chamber of the internal combustion engine 10 flows through the exhaust passage 11a inside the exhaust pipe 11, is purified by the purification device 20 or the like, and then is discharged to the atmosphere. The purification device 20 has a function of reducing and purifying NOx (nitrogen oxide) contained in the exhaust gas and a function of collecting particulate matter (PM). The purification device 20 includes a passage member 21 connected to the exhaust pipe 11, a base material 22 housed inside the passage member 21 to purify the exhaust gas, and a catalyst layer supported by the base material 22.

The base material 22 is made of ceramic formed in a honeycomb shape, and the outer shape of the base material 22 is a cylindrical shape extending in the exhaust flow direction. Of both end faces of the cylinder of the base material 22, the end faces on the upstream side of the exhaust flow function as the exhaust inflow port 22a. The catalyst layer contains a reduction catalyst component and an adsorption component described below. The reduction catalyst component is a component for reducing NOx contained in the exhaust gas, and for example, platinum is used. Zeolite is used as the adsorbing component, and it physically adsorbs ammonia, which will be described later.

A reducing agent injection valve 30 for injecting a reducing agent is attached to the upstream portion of the purification device 20 in the exhaust pipe 11. In this embodiment, a liquid reducing agent (for example, urea water) is used. The urea water injected into the exhaust passage 11a is hydrolyzed by the exhaust heat. As a result, gaseous ammonia is generated in the exhaust passage 11a. The generated ammonia flows into the base material 22 from the exhaust inlet 22a and is adsorbed on the catalyst layer. Specifically, ammonia is physically adsorbed on the adsorbed component contained in the catalyst layer.

A part of the adsorbed ammonia reduces NOx contained in the exhaust gas on the reducing catalyst component contained in the catalyst layer. Therefore, strictly speaking, it cannot be said to be a reducing agent in the state of urea water injected from the reducing agent injection valve 30, and ammonia produced by hydrolysis of the urea water acts as a reducing agent. However, in the present embodiment, urea water, which can be said to be a raw material for ammonia, may be simply referred to as a reducing agent, and this urea water corresponds to the reducing agent described in the claims.

The reducing agent injection valve 30 includes a body 31, a valve body 32, and an electric actuator 33. The body 31 houses the valve body 32 and the electric actuator 33 inside. When the valve body 32 is opened by the electromagnetic attraction generated by energizing the electric actuator 33, urea water is injected into the exhaust passage 11a from the injection hole 51 (see FIG. 3) formed in the body 31.

A part of the body 31 is located in the exhaust passage 11a and is exposed to the exhaust gas. A jet hole 51 for injecting urea water is formed in a portion of the body 31 exposed to the exhaust gas. The reducing agent injection valve 30 according to the present embodiment includes one injection hole 51, but may include a plurality of injection holes 51. The urea water injected from the injection hole 51 forms a conical spray F (see FIG. 1).

The vehicle is equipped with a tank 30T for storing urea water and a pump 30P for pumping the urea water stored in the tank 30T to the reducing agent injection valve 30. The pump 30P is an electric type driven by an electric motor. By controlling the electric power supplied to the pump 30P, the pressure of the urea water supplied to the reducing agent injection valve 30 is controlled, and by extension, the injection pressure of the urea water from the injection hole 51 is controlled.

An electronic control device (hereinafter referred to as ECU) (not shown) controls the start and stop of injection of urea water from the injection hole 51 by controlling the energization of the electric actuator 33. Further, the ECU controls the injection pressure of urea water by controlling the power supplied to the electric motor of the pump 30P. The reducing agent injection system according to the present embodiment includes an ECU and a reducing agent injection valve 30. The exhaust gas purification system according to the present embodiment includes a purification device 20 in addition to the reducing agent injection system.

Next, the structure of the reducing agent injection valve 30 will be described in detail with reference to FIG.

The electric actuator 33 of the reducing agent injection valve 30 has an electromagnetic coil 331, a fixed core 332, and a movable core 333. When the electromagnetic coil 331 is energized, magnetic flux is generated in the fixed core 332 and the movable core 333, and the movable core 333 is attracted to the fixed core 332 by the electromagnetic attraction force due to the magnetic flux. Since the movable core 333 is attached to the valve body 32, the valve body 32 reciprocates together with the movable core 333 in the central axis C direction.

The body 31 of the reducing agent injection valve 30 has a base end side body 311, a non-magnetic member 312, a tip end side body 313, a magnetic member 314, a plate member 40, and a jet hole member 50. The base end side body 311 has a cylindrical shape that holds a fixed core 332 inside. The non-magnetic member 312 is arranged between the base end side body 311 and the tip end side body 313, and blocks the above-mentioned magnetic flux. The tip side body 313 has a cylindrical shape that houses the valve body 32 inside. A seat surface 313s on which the seat surface 32s provided at the tip of the valve body 32 is detached and seated is formed on the inner peripheral surface of the cylinder of the tip side body 313 (see FIG. 3).

The urea water supplied from the base end of the base end side body 311 passes through the internal passage 311a of the base end side body 311, the internal passage 332a of the fixed core 332, the internal passage 333a of the movable core 333, and the internal passage 32a of the valve body 32. It will be distributed in order. After that, the urea water in the internal passage 32a flows out from the outlet 32b (see FIG. 2) and the outlet 32c (FIG. 3 and) formed on the side wall of the valve body 32. Then, the annular passage 313a formed between the inner peripheral surface of the tip side body 313 and the outer peripheral surface of the valve body 32 and the merging passage 313b along the tip of the valve body 32 are sequentially circulated. The annular aisle 313a is opened and closed when the valve body 32 is taken off and seated on the seat surface 313s. In the merging passage 313b, urea water distributed in a ring shape in the annular passage 313a is merged and distributed in a disk shape including the central axis C. The central axis of the annular passage 313a, the merging passage 313b, and the injection hole 51 coincides with the central axis C of the valve body 32.

As shown in FIGS. 2 to 4, a plate member 40 and a jet hole member 50 are attached to the tip of the tip side body 313. The plate member 40 is arranged between the tip side body 313 and the injection hole member 50. For example, the tip side body 313, the plate member 40, and the injection hole member 50 are joined by welding.

The plate member 40 has a disk-shaped plate 41 that covers the confluence passage 313b from the injection hole side, and a cylindrical portion 42 that extends from the outer peripheral end of the plate 41 along the outer peripheral surface of the tip side body 313. The plate 41 is formed with a first through hole 43 and a second through hole 44 that communicate with the merging passage 313b. The first through hole 43 and the second through hole 44 are formed in a state of being separated from each other in the plate 41 without communicating with each other.

As shown in FIG. 5, the first through hole 43 and the second through hole 44 have an arc shape extending around the central axis C. The arc length of the first through hole 43 and the arc length of the second through hole 44 are the same. The radial positions of the outer peripheral edges of the first through hole 43 and the second through hole 44 are the same as the radial positions of the outer peripheral edges of the merging passage 313b. The surface of the plate 41 on the anti-injection hole side has a flat shape extending perpendicular to the central axis C.

The injection hole member 50 is formed with one injection hole 51 for injecting urea water. The injection hole 51 has a shape extending in the central axis C direction along the central axis C of the injection hole member 50, and has a shape in which the passage cross-sectional area becomes larger toward the downstream side (see FIG. 5). The downstream end opening 51b of the injection hole 51 has a circular shape centered on the central axis C. An annular groove 52 surrounding the downstream end opening 51b is formed on the end surface of the injection hole member 50 on the side opposite to the plate member 40. By forming the annular groove 52, it is possible to prevent urea water from adhering to the peripheral portion of the downstream end opening 51b of the end surface of the injection hole member 50 due to surface tension.

On the surface of the injection hole member 50 that contacts the plate 41, a first distribution unit 53 and a second distribution unit 54 that extend in different directions to flow urea water are formed. These distribution portions have a groove shape that opens toward the plate 41, and the groove opening is covered by the plate 41. The first distribution unit 53 and the second distribution unit 54 are arranged so as to extend on the same plane, extend linearly in the radial direction, and extend in parallel with each other.

Further, on the surface of the injection hole member 50 that contacts the plate 41, the urea water that has flowed through the first distribution section 53 and the urea water that has flowed through the second distribution section 54 are merged at the center of the injection hole member 50. A merging portion 55 is formed to guide the merging urea water to the injection hole 51. The merging portion 55 has a vortex generation portion 55a and a vortex outflow portion 55b (see FIG. 4).

The vortex generation portion 55a has a cylindrical shape extending in the central axis C direction. The vortex generation unit 55a communicates with the downstream end of the first distribution unit 53 and the downstream end of the second distribution unit 54. In the following description, the inflow port flowing from the first distribution section 53 into the vortex generation section 55a is the first inflow port 53a, and the inflow port flowing from the second distribution section 54 into the vortex generation section 55a is the second inflow port 54a. Called.

The vortex outflow portion 55b has a conical shape extending along the central axis C, and the passage cross-sectional area becomes smaller toward the downstream side. The upstream end of the vortex outflow portion 55b communicates with the downstream end of the vortex generation portion 55a, and the downstream end of the vortex outflow portion 55b communicates with the upstream end of the injection hole 51.

Next, the flow of urea water from the merging passage 313b to the downstream end opening 51b will be described in detail with reference to FIGS. 5 to 7. In the following description, the portion of the first through hole 43 that communicates with the first communication section 53 is referred to as the first communication section 43a, and the portion of the second through hole 44 that communicates with the second communication section 54 is the second. It is called the communication unit 44a. The portion of the first through hole 43 on one end side and the other end side of the first communication portion 43a are referred to as first passages 43b and 43c, and one end side of the second through hole 44 with respect to the second communication portion 44a. The portion and the portion on the other end side are referred to as the second passages 44b and 44c, respectively. The first communication portion 43a is arranged in the central portion of the first through hole 43, and the passage lengths of the two first passages 43b and 43c are the same. Similarly, the second communication portion 44a is arranged in the central portion of the second through hole 44, and the passage lengths of the two second passages 44b and 44c are the same.

The urea water that has merged from the annular passage 313a to the merging passage 313b flows into the first through hole 43 and the second through hole 44. Specifically, the urea water located directly above the first through hole 43 and the second through hole 44 in the merging passage 313b flows into the first through hole 43 and the second through hole 44 as it is. As shown by the arrow F1 in FIG. 5, the urea water at a position deviated from directly above flows along the surface of the plate 41 and flows into the first through hole 43 and the second through hole 44.

The urea water that has flowed into the first through hole 43 flows toward the first communication portion 43a. Then, urea water flowing from one end side of both ends of the arc of the first through hole 43 toward the first communication portion 43a (see arrow F2) and urea water flowing from the other end side toward the first communication portion 43a (arrow F3). (See) collide with the first communication portion 43a. That is, the urea water flowing through the two first passages 43b and 43c, respectively, collides head-on at the first communication portion 43a. Due to this collision, the turbulent energy of the urea water is increased, and the urea water in a state having a large turbulent energy, that is, a state having a large number of fine vortices, is the radial outer end of both ends of the first flow unit 53. It flows into the department.

Similarly, the urea water flowing from one end side of both ends of the arc of the second through hole 44 toward the second communication portion 44a and the urea water flowing from the other end side toward the second communication portion 44a are in the second communication. Collision at part 44a. That is, the urea water flowing through the two second passages 44b and 44c, respectively, collides head-on at the second communication portion 44a. Due to this collision, the turbulent energy of the urea water is increased, and the urea water in a state having a large turbulent energy, that is, a state having a large number of fine vortices, is the radial outer end of both ends of the second flow portion 54. It flows into the department.

The urea water that has flowed into each of the first distribution section 53 and the second distribution section 54 flows toward the vortex generation section 55a of the confluence section 55. Then, the urea water (see arrow F4) that flows through the first flow section 53 and flows into the vortex generation section 55a from the first inflow port 53a and the vortex generation section 55a that flows through the second flow section 54 and flows from the second inflow port 54a to the vortex generation section 55a. The urea water (see arrow F5) that has flowed into the vortex generating portion 55a collides with the urea water.

Specifically, since the first inflow port 53a and the second inflow port 54a are arranged to face each other, the urea water flowing in from the first inflow port 53a and the urea water flowing in from the second inflow port 54a collide head-on. Due to this collision, the turbulent energy of the urea water is increased, and the urea water having a large turbulent energy, that is, having a large number of fine vortices flows from the vortex generation portion 55a to the vortex outflow portion 55b. The above-mentioned turbulent energy can be said to be the sum of the kinetic energies of a plurality of vortices contained in urea water.

The urea water whose turbulent energy has been increased in this way circulates in order to the vortex outflow portion 55b and the injection hole 51 while trying to expand the volume, and thereafter, from the downstream end opening 51b while trying to expand the volume. Be jetted. Therefore, even immediately after the injection is performed from the downstream end opening 51b, the volume is increased, so that the angle of the spray F becomes large.

The internal passages 311a, 332a, 333a, 32a, the annular passage 313a, the merging passage 313b, the first through hole 43, the second through hole 44, the first distribution section 53, the second distribution section 54, and the merging section 55 are sprayed. It corresponds to the supply flow path 30F for supplying the reducing agent to the hole 51. Further, the first through hole 43 is a first flow path portion that collides the urea water flowing in from one end side with the urea water flowing in from the other end side and guides the urea water after the collision to the first distribution section 53. Corresponds to. The second through hole 44 corresponds to a second flow path portion that collides the urea water flowing in from one end side with the urea water flowing in from the other end side and guides the urea water after the collision to the second distribution section 54. do.

Next, the dimensions of each part of the supply flow path 30F will be described.

The diameter D1 of the injection hole 51 (see FIG. 4) is smaller than the diameter D2 of the vortex generating portion 55a (see FIG. 6). The depth dimension L2 of the first distribution unit 53 in the opening / closing operation direction (center axis C direction) of the valve body 32 and the depth dimension L2 of the second distribution unit 54 are the same. The depth dimension L3 of the merging portion 55 is longer than the depth dimension L2 of the first distribution portion 53 (see FIG. 4). The vortex generation section 55a has a shape in which the width dimension L5 of the first distribution section 53 and the width dimension L5 of the second distribution section 54 are widened when viewed from the central axis C direction. That is, the diameter D2 of the vortex generation portion 55a is larger than the width dimension L5 (see FIG. 6). The width dimension L5 of the first distribution section 53 and the width dimension L5 of the second distribution section 54 are the same.

Here, the ratio of the depth dimension L1 of the first through hole 43 and the second through hole 44 to the depth dimension L2 of the first distribution section 53 and the second distribution section 54 is described as L1 / L2 in the following description. do. The depth dimension L1 of the first through hole 43 corresponds to the depth of the first flow path, and the depth dimension L2 of the first distribution section 53 corresponds to the first distribution depth.

The present inventors simulated the relationship between the turbulent energy distribution of urea water in the supply passage 30F and L1 / L2. In the column (1) of FIG. 8, L1 / L2 is 0.24, in the column (2), L1 / L2 is 0.6, and in the column (3), L1 / L2 is 1.2. Show the case. Further, FIG. 8 represents a cross section along the line VIII-VIII of FIG. 6, and the magnitude of the turbulent energy is represented by dividing it into four stages indicated by reference numerals E1 to E4. The shaded area with reference numeral E1 indicates the region having the largest turbulent energy, and the turbulent energy decreases in the order of E1, E2, E3, and E4.

From this simulation result, the present inventors obtained the following findings. In the case of the column (2) in which L1 / L2 is 0.6, the E1 region is expanded as compared with the column (1). Further, in the case of the column (3) in which L1 / L2 is 1.2, the E1 region is shifted downward as compared with the column (2). Therefore, as can be seen by comparing the distributions in the dotted lines shown by the symbols W1 and W2, the size of the E1 region in the vortex generation unit 55a is smaller in the column (3) than in the column (2). These results mean that there is an optimum range of L1 / L2 for increasing the turbulent energy in the vortex generation unit 55a.

The optimum range is 0.24 or more and less than 1.2 as shown in FIG. 9, and especially when L1 / L2 is 0.5, the turbulent energy at the vortex generation unit 55a peaks. The turbulent energy shown on the vertical axis of FIG. 9 is the sum of the turbulent energy distributed in the vortex generation section 55a. The energy is a large value. In view of this simulation result, in the present embodiment, the supply flow path 30F is set so that L1 / L2 is 0.24 or more and less than 1.2, and more specifically, L1 / L2 is 0.5. It is formed.

Further, a direction perpendicular to the flow direction of urea water in the first through hole 43 and perpendicular to the opening / closing operation direction of the valve body (center axis C direction) is referred to as a width direction. The dimension L4 of the first through hole 43 in the width direction corresponds to the width of the first flow path, and the dimension L5 of the first distribution section 53 in the width direction corresponds to the first distribution width (see FIG. 6). Further, the ratio of the first flow path width L4 to the first distribution width L5 is described as L4 / L5 in the following description.

Then, the present inventors have also obtained the simulation results shown in FIG. 10 regarding the relationship between the total distribution of turbulent energy and L4 / L5. According to this result, it means that the optimum range of L4 / L5 exists in order to increase the turbulent flow energy in the vortex generation unit 55a. The optimum range is 0.4 or more and less than 0.6 as shown in FIG. 10, and particularly when L4 / L5 is 0.5, the turbulent energy at the vortex generation unit 55a peaks. In view of this simulation result, in the present embodiment, the supply flow path 30F is set so that L4 / L5 is 0.4 or more and less than 0.6, and more specifically, L4 / L5 is 0.5. It is formed.

The simulation of FIG. 9 relating to L1 / L2 confirms that the same result is obtained if L4 / L5 is in the range of 0.4 or more and less than 0.6. That is, as L1 / L2 is increased, the turbulent energy rises sharply from 0.24, peaks at 0.5, and drops sharply from 1.2.

Based on the above, according to the present embodiment, the supply flow path 30F for supplying urea water to the injection hole 51 includes a first through hole 43 (first flow path portion) and a second through hole 44 (second flow path portion). , A first distribution unit 53, a second distribution unit 54, and a merging unit 55. The through holes 43 and 44 form a flow path that causes the urea water flowing in from one end side and the urea water flowing in from the other end side to collide with each other. The respective flow units 53 and 54 communicate with the respective through holes 43 and 44 to circulate the urea water that has collided with the through holes. Then, the merging section 55 merges the urea water that has flowed through the respective distribution sections 53 and 54, and guides the merged urea water to the injection hole 51.

According to this, the reducing agents collide with each other (pre-collision) in each of the first through hole 43 and the second through hole 44, and the pre-collision reducing agents further collide with each other at the merging portion 55. In this way, since the first communication portion 43a and the second communication portion 44a are pre-collised before the collision at the merging portion 55, the turbulent energy of the urea water can be increased by the amount of the pre-collision. The larger the turbulent energy, the greater the force acting to expand the volume of the spray F, so that the urea water can be guided to the injection hole 51 in a state where the volume expansion tendency is strong. Therefore, according to the present embodiment, the urea water injected from the injection hole 51 can be made into a spray F in a state of being greatly expanded in the radial direction, and the angle of the urea water spray F can be widened.

In the comparative example shown in FIG. 7, the first through hole 43 and the second through hole 44 according to the present embodiment are provided with the first through hole 43P and the second passage 44b, 44c in which the first passage 43b, 43c is abolished. It is replaced with the abolished second through hole 44P. In this case, the urea water distributed in the merging passage 313b flows evenly from around the first through hole 43 and the second through hole 44, so that the urea water collides with the first through hole 43 and the second through hole 44. Rarely occurs. On the other hand, in the present embodiment, the first through hole 43P has the first passages 43b and 43c, and the second through hole 44P has the second passages 44b and 44c. At 44, urea water is urged to collide.

Further, in the present embodiment, the first through hole 43 and the second through hole 44 are separated without being directly communicated with each other. That is, both ends of the first through hole 43 and both ends of the second through hole 44 do not communicate with each other to form an annular shape, and each of the first through hole 43 and the second through hole 44 has an arc shape.

Here, contrary to the present embodiment, if both ends of the first through hole 43 and both ends of the second through hole 44 communicate with each other to form an annular shape, the most upstream portion of the annular flow path, that is, the communicated portion It is difficult to determine the direction in which the urea water flows toward the first communication portion 43a or the second communication portion 44a. Therefore, the flow velocity of the urea water up to the first communication portion 43a and the second communication portion 44a cannot be sufficiently increased. Therefore, the pre-collision cannot be sufficiently increased, and the turbulent energy cannot be sufficiently promoted.

On the other hand, according to the present embodiment, since the first through hole 43 and the second through hole 44 are separated, the urea water flowing into these through holes 43 and 44 is sent to any of the communication portions 43a and 44a. It is decided whether it will flow toward you. Therefore, the flow velocity of the urea water when it flows through the first passages 43b and 43c and reaches the first communication portion 43a, and the urea water when it flows through the second passages 44b and 44c and reaches the second communication portion 44a. Can increase the flow velocity of. Therefore, the pre-collision can be promoted to increase the turbulent energy, and the urea water spray F can be promoted to widen the angle.

Further, in the present embodiment, among the flow path lengths of the first through hole 43, the flow path length on one end side of the first communication portion 43a and the flow path length on the other end side of the first communication portion 43a are the same. .. That is, the passage lengths of the two first passages 43b and 43c are the same. Therefore, the urea water pre-collides with the portion of the first through hole 43 that communicates with the first communication portion 53, that is, the first communication portion 43a. It can flow into the first distribution unit 53. Therefore, the turbulent energy after the collision at the merging portion 55 can be increased, and the widening of the spray F can be promoted.

The same applies to the second through hole 44, and since the passage lengths of the two second passages 44b and 44c are the same, the portion of the second through hole 44 that communicates with the second communication portion 54, that is, the second communication portion Urea water pre-collides at 44a. Therefore, since the urea water can flow into the second flow section 54 while the turbulent energy immediately after the pre-collision is high, the turbulent energy after the collision at the confluence 55 can be increased, and the wide angle of the spray F can be increased. Can promote the conversion.

Further, the reducing agent injection valve 30 according to the present embodiment includes a tip side body 313, an injection hole member 50 in which the injection hole 51 is formed, and a plate member 40. The tip side body 313 forms the seat surface 313s and houses the valve body 32 inside. The plate member 40 is arranged adjacent to the tip side body 313 and the injection hole member 50. The first flow section 53 and the second flow section 54 are formed in the injection hole member 50, and the first through hole 43 and the second through hole 44 are formed in the plate member 40.

According to this, the injection hole side openings of the first through hole 43 and the second through hole 44 are covered with the injection hole member 50, and the anti-injection hole side opening is covered with the tip side body 313. Therefore, a plate member 40 in which the through holes 43 and 44 are formed is prepared, and the plate member 40 is sandwiched between the tip side body 313 and the injection hole member 50 to cause a pre-collision in the flow path portions 43 and 44. It is possible to easily realize a structure in which a collision occurs in two stages with a collision at the confluence portion 55.

Further, in the present embodiment, the vortex generation portion 55a of the merging portion 55 has a shape in which the width dimension L5 of the first distribution portion 53 and the width dimension L5 of the second distribution portion 54 are widened when viewed from the central axis C direction. .. Therefore, a sufficient space for generating a large number of vortices can be secured in the vortex generation unit 55a, the vortex generation of urea water can be promoted, and the widening of the spray F can be promoted.

Further, in the present embodiment, in view of the simulation result shown in FIG. 9, since the supply flow path 30F is formed so that L1 / L2 is 0.24 or more and less than 1.2, turbulence in the vortex generation unit 55a The energy can be increased and the widening of the spray F can be promoted.

Further, in the present embodiment, in view of the simulation result shown in FIG. 10, since the supply flow path 30F is formed so that L4 / L5 is 0.4 or more and less than 0.6, turbulence in the vortex generation unit 55a The energy can be increased and the widening of the spray F can be promoted.

(Other embodiments)
The reducing agent injection valve described in the claims can be implemented in various modifications as illustrated below without being limited to the above-described embodiment. Not only the combination of the parts that clearly indicate that the combination is possible in each embodiment, but also the partial combination of the embodiments even if the combination is not specified if there is no problem in the combination. Is also possible.

In the first embodiment, the width direction dimension L4 (flow path width) of the first through hole 43 and the second through hole 44 is constant. On the other hand, the width of these flow paths may be gradually reduced. In the first embodiment, the width direction dimension L5 (distribution width) of the first distribution unit 53 and the second distribution unit 54 is constant. On the other hand, these distribution widths may be gradually reduced.

In the first embodiment, the merging portion 55 has a shape in which the width dimension L5 of the first distribution portion 53 and the width dimension L5 of the second distribution portion are widened when viewed from the central axis C direction. It may have a shape in which the dimension L5 is reduced. For example, the diameter D2 of the vortex generation unit 55a may be larger or smaller than the width dimension L5 of the first distribution unit 53 and the second distribution unit.

In the first embodiment, the first distribution unit 53 and the second distribution unit 54 are arranged on the same plane and have a shape extending perpendicular to the central axis C. On the other hand, the first distribution unit 53 and the second distribution unit 54 have a shape extending in a direction inclined with respect to a plane perpendicular to the central axis C in a cross-sectional view including the central axis C (see FIG. 4). May be good. For example, the first distribution unit 53 and the second distribution unit 54 may have a shape extending in a direction inclined with respect to a plane perpendicular to the central axis C.

In each of the above embodiments, the diameter D2 of the merging portion 55 is set to be smaller than the flow path length of the second distribution section 54 or the merging section 55, but may be set to be larger than these flow path lengths.

In each of the above embodiments, the first through hole 43 and the second through hole 44 have the same shape, and the first distribution unit 53 and the second distribution unit 54 have the same shape, but they may have different shapes. Further, instead of arranging them symmetrically with respect to the central axis C, they may be arranged asymmetrically.

In each of the above embodiments, the number of injection holes 51 formed in the injection hole member 50 is one. On the other hand, a plurality of injection holes 51 may be formed in the injection hole member 50. For example, a plurality of injection holes may be branched from one merging portion 55 so that the urea water in the merging portion 55 is distributed to the plurality of injection holes.

In each of the above embodiments, the first through hole 43 (first flow path portion) and the second through hole 44 (second flow path portion) are separated without direct communication, but these through holes 43, 44 may communicate with the plate member 40. For example, one end of the first passage 43b of the first through hole 43 and one end of the second passage 44b of the second through hole 44 may communicate with each other.

In each of the above embodiments, among the flow path lengths of the first through hole 43, the flow path length on one end side of the first communication portion 43a and the flow path length on the other end side of the first communication portion 43a are the same. , These flow path lengths may be different. Similarly, of the flow path lengths of the second communication hole 44, even if the flow path length on one end side of the second communication portion 44a and the flow path length on the other end side of the second communication portion 44a are the same. It may or may not be different.

In each of the above embodiments, the first through hole 43 (first flow path portion) and the second through hole 44 (second flow) are formed in the plate member 40 arranged adjacent to the body 31 and the injection hole member 50. Road part) is formed. On the other hand, the plate member 40 may be abolished and the through holes 43 and 44 may be formed in the body 31 or the injection hole member 50.

In each of the above embodiments, the material of the plate member 40 is made of metal, but it may be made of resin. Similarly, the material of the injection hole member 50 is not limited to metal, but may be resin. The reducing agent injection valve according to each of the above embodiments injects urea water as a reducing agent, but may inject a liquid hydrocarbon compound as a reducing agent.

30 ... Reducing agent injection valve, 30F ... Supply flow path, 31 ... Body, 32 ... Valve body, 40 ... Plate member, 43 ... First through hole (first flow path portion), 43a ... First communication section, 44 ... 2nd through hole (second flow path portion), 44a ... 2nd communication portion, 50 ... injection hole member, 51 ... injection hole, 53 ... first distribution unit, 54 ... second distribution unit, 55 ... confluence portion.

Claims (6)

An internal combustion engine (10) including an injection hole (51) for injecting a reducing agent, a supply flow path (30F) for supplying the reducing agent to the injection hole, and a valve body (32) for opening and closing the supply flow path. ), Which is a reducing agent injection valve that injects the reducing agent to the upstream side of the purification device (20) in the exhaust passage (11a).
The supply flow path is
The first flow path portion (43) that causes the reducing agent that has flowed in from one end side and the reducing agent that has flowed in from the other end side to collide with each other.
A second flow path portion (44) that causes the reducing agent that has flowed in from one end side and the reducing agent that has flowed in from the other end side to collide with each other.
A first flow unit (53) that communicates with the first flow path portion and circulates a reducing agent that collides with the first flow path portion.
A second flow section (54) that communicates with the second flow path and circulates the reducing agent that collides with the second flow path.
The first was flowing part and distribution reducing agent to merge with a reducing agent that flows through the second flowing part, merging unit confluence reducing agent leads to the injection hole (55), which have a,
The first flow section and the second flow section extend radially from the confluence portion extending along the central axis (C) of the valve body toward opposite sides via the central axis. Reducing agent injection valve. The reducing agent injection valve according to claim 1, wherein the first flow path portion and the second flow path portion are separated without being directly communicated with each other. The portion of the first flow path portion that communicates with the first communication portion is referred to as a first communication portion (43a).
The portion of the second flow path portion that communicates with the second communication portion is referred to as a second communication portion (44a).
Of the flow path lengths of the first communication portion, the flow path length on one end side of the first communication portion and the flow path length on the other end side of the first communication portion are the same.
According to claim 1 or 2, among the flow path lengths of the second communication portion, the flow path length on one end side of the second communication portion and the flow path length on the other end side of the second communication portion are the same. The reducing agent injection valve described. A body (31) in which a portion of the supply flow path that is opened and closed by the valve body is formed and accommodates the valve body inside,
The injection hole member (50) in which the injection hole is formed and
A plate member (40) arranged adjacent to the body and the injection hole member,
With
The first distribution unit and the second distribution unit are formed in the injection hole member, and the first distribution unit and the second distribution unit are formed in the injection hole member.
The reducing agent injection valve according to any one of claims 1 to 3, wherein the first flow path portion and the second flow path portion are formed on the plate member. The dimension of the first flow path portion in the opening / closing operation direction of the valve body is called the first flow path depth (L1), and the dimension of the first flow section in the opening / closing operation direction is the first flow depth (L2). In any one of claims 1 to 4, the ratio (L1 / L2) of the first flow path depth to the first distribution depth is in the range of 0.24 or more and less than 1.2. The reducing agent injection valve described. The width direction is the direction perpendicular to the flow direction of the reducing agent in the first flow path portion and the direction perpendicular to the opening / closing operation direction of the valve body, and the dimension of the first flow path portion in the width direction is the first flow path. When the width (L4) is referred to and the dimension of the first distribution section in the width direction is referred to as the first distribution width (L5), the ratio of the first flow path width to the first distribution width (L4 / L5). The reducing agent injection valve according to any one of claims 1 to 5, wherein the reducing agent injection valve is 0.4 or more and less than 0.6.

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