JP2019157781A - Additive agent dispersion system of internal combustion engine - Google Patents

Abstract

To provide an additive agent dispersion system of an internal combustion engine capable of reducing pressure loss of an exhaust gas in an exhaust pipe of the internal combustion engine, and properly atomizing an additive agent injected from an addition valve and properly dispersing same into the exhaust gas in the exhaust pipe even when a flow rate and a flow volume of the exhaust gas are increased.SOLUTION: The additive agent dispersion system of an internal combustion engine is provided that disperses an additive agent 61A injected from an addition valve 61 into an exhaust gas flowing in exhaust pipes 43R, 43L. A flow rate reduction area 90A where a flow rate of the exhaust gas is lower than a flow rate of the circumference exhaust gas is formed at a part of an inner wall in a longitudinal direction and a circumferential direction of the exhaust pipe 43R in a position upstream of an exhaust emission control device (71), and the addition valve 61 is disposed in such a manner that the additive agent 61A injected from the addition valve 61, passes through only the flow rate reduction areas 90 and collides with the inner wall of the exhaust pipe 43R in the flow rate reduction area 90A.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an additive dispersion system for an internal combustion engine in which an additive for use in purification of exhaust gas is dispersed in exhaust gas in an exhaust pipe of the internal combustion engine.

  For example, in a diesel engine which is one of internal combustion engines, an oxidation catalyst, a DPF (Diesel Particulate Filter), and a urea SCR (selective reduction catalyst) may be arranged in order from the upstream side of the exhaust pipe as an exhaust purification device. is there. Oxidation catalyst oxidizes carbon monoxide (CO), hydrocarbon (HC), etc. in exhaust gas to make them harmless, DPF collects particulate matter such as soot in exhaust gas, and urea SCR in exhaust gas The nitrogen oxide (NOx) is reduced and rendered harmless. When the particulate matter collected by the DPF reaches a predetermined amount or more, the fuel (additive) is injected into the exhaust pipe from the upstream side of the oxidation catalyst using the fuel addition valve. The temperature of the exhaust gas is forcibly raised by the reaction, and the particulate matter in the DPF is burned and removed by using the exhaust gas that has become hot. When performing the reduction process of urea SCR, urea water (additive) is injected into the exhaust pipe from the upstream side of the urea SCR using the urea water addition valve, and the reduction process is performed in the urea SCR.

In order to effectively detoxify harmful components in the exhaust gas, the fuel (additive) injected from the fuel addition valve is uniformly dispersed in the exhaust gas in the exhaust pipe and injected from the urea water addition valve It is necessary to uniformly disperse the aqueous urea solution (additive) in the exhaust gas in the exhaust pipe. The following (Method 1) to (Method 3) can be considered as a method of adding and dispersing the fuel in the exhaust gas.
(Method 1) A method of injecting into exhaust gas after combustion in a cylinder.
(Method 2) A method of injecting into exhaust gas in an exhaust path (exhaust manifold, etc.) from the cylinder to the turbo turbine.
(Method 3) A method of injecting into the exhaust gas in the exhaust path downstream of the turbo turbine.

  The above (Method 1) has an advantage that the additive is easily dispersed uniformly in the exhaust gas. However, there is a disadvantage that the engine oil may be diluted due to adhesion of unburned fuel in the cylinder. Have. In addition, the above (Method 2) has an advantage that the additive is easily dispersed uniformly in the exhaust gas, but has a disadvantage that the turbine performance may be deteriorated due to fuel adhering to the turbo turbine. ing. The above (Method 3) has the advantage that the disadvantages of the above (Method 1) and (Method 2) can be avoided, but the disadvantage that it is difficult to uniformly disperse the additive in the exhaust gas. Have. In the above (Method 3), the additive at the time of injection from the addition valve has a relatively large particle size and is difficult to efficiently disperse in the exhaust gas. Therefore, in general, a dispersion plate is arranged in the exhaust pipe, the additive is injected toward the dispersion plate, and the additive collides with the dispersion plate to atomize, thereby adding the additive into the exhaust gas. Promotes the dispersion of The following Patent Document 1 and Patent Document 2 both use the above (Method 3). A dispersion plate is arranged in the exhaust pipe, and the additive collides with the dispersion plate so that the additive is uniformly distributed in the exhaust gas. Are dispersed.

  For example, in Patent Document 1, a planar partition wall (corresponding to a dispersion plate) extending in the longitudinal direction of the exhaust pipe is formed in the central portion of the substantially horizontal exhaust pipe in the vicinity of the additive injection device (corresponding to the addition valve). An exhaust passage structure is disclosed in which the exhaust pipe is divided and divided into two regions, a kamaboko-shaped upper partition region and a lower partition region. And the additive injection apparatus injects an additive so that it may become a predetermined | prescribed inclination angle with respect to a division wall toward the upper surface of a division wall and toward the downstream from an upstream. The additive injected from the additive injection device collides with the upper surface of the partition wall across the flow of the exhaust gas in the upper partition region, and is atomized to be dispersed in the upper partition region. Dispersed throughout the exhaust pipe from the merged portion (after the downstream end portion of the partition wall) where the partitioned regions merge.

  Further, Patent Document 2 discloses an additive dispersion plate structure of an exhaust passage in which an additive dispersion plate extending in the longitudinal direction of the exhaust pipe is disposed in the center of the exhaust pipe in the vicinity of the injection port (corresponding to the addition valve). Has been. The injection port injects the additive toward the upper surface of the additive dispersion plate and from the upstream side toward the downstream side so as to have a predetermined inclination angle with respect to the additive dispersion plate. The additive dispersion plate is configured by arranging a plurality of plate-like members along the longitudinal direction of the exhaust pipe. The longitudinal direction of each plate-like member is orthogonal to the longitudinal direction of the exhaust pipe, and the downstream edge of each plate-like member is arranged to be higher than the upstream edge, so that the inclined surface (impact Part). A predetermined gap is provided between the plate-like members adjacent in the longitudinal direction of the exhaust pipe, and a passage portion communicating from the upper surface side to the lower surface side of the additive dispersion plate is formed. The additive injected from the injection port collides with each inclined surface (collision part) on the upper surface of the additive dispersion plate across the flow of the exhaust gas and is atomized. A part of the atomized additive is dispersed in the exhaust gas flowing on the upper surface side of the additive dispersion plate, and the remainder of the atomized additive passes through the passage portion of the additive dispersion plate. It flows to the lower surface side of the dispersion plate and is dispersed in the exhaust gas flowing on the lower surface side of the additive dispersion plate.

JP 2009-162122 A JP 2009-68460 A

  The additive dispersion systems described in Patent Literature 1 and Patent Literature 2 both have a dispersion plate in the exhaust pipe, and both dispersion plates are arranged in the central portion of the exhaust pipe along the longitudinal direction of the exhaust pipe. Has been placed. For this reason, since the dispersion plate is disposed in a region (central portion) where the flow velocity of the exhaust gas flowing through the exhaust pipe is the largest, there is a concern about pressure loss of the exhaust gas. The pressure loss of the exhaust gas becomes a factor that decreases the output and fuel consumption of the internal combustion engine.

  In addition, in any of the additive dispersion systems described in Patent Document 1 and Patent Document 2, the additive injected from the addition valve crosses the region where the exhaust gas flow velocity is the highest (the central portion in the exhaust pipe). The exhaust gas collides with a dispersion plate arranged in a region where the flow velocity of the exhaust gas is the largest. For this reason, when the internal combustion engine is operated at a high rotation speed and the flow rate and flow rate of the exhaust gas are very large, a part of the additive injected from the addition valve flows into the exhaust gas at a high speed and a large flow rate (operation There is a possibility that it will flow to the downstream of the dispersion plate without colliding with the dispersion plate. In this case, the additive that has not collided with the dispersion plate is not atomized and has a relatively large particle size and may not be properly dispersed in the exhaust gas.

  The present invention has been devised in view of the above points, and further reduces the pressure loss of exhaust gas in the exhaust pipe of an internal combustion engine, and even if the flow rate and flow rate of the exhaust gas are increased, It is an object of the present invention to provide an additive dispersion system for an internal combustion engine that can properly atomize the injected additive and disperse it appropriately in the exhaust gas in the exhaust pipe.

  In order to solve the above problems, a first invention of the present invention has an addition valve for injecting an additive into an exhaust pipe of an internal combustion engine upstream of the exhaust purification device, and is injected from the addition valve. An additive dispersion system for an internal combustion engine that disperses an additive in an exhaust gas flowing in the exhaust pipe, wherein the additive pipe is a part of a longitudinal direction in the exhaust pipe that is upstream of the exhaust purification device and in a circumferential direction. Around the inner wall, there is formed a flow rate delay region where the flow rate of the exhaust gas is slower than the flow rate of the surrounding exhaust gas, and the additive injected from the addition valve passes only within the flow rate delay region. An additive dispersion system for an internal combustion engine, wherein the addition valve is arranged to collide with an inner wall of the exhaust pipe in the flow velocity delay region.

  Next, a second invention of the present invention is the additive dispersion system for an internal combustion engine according to the first invention, wherein the flow rate delay region is a longitudinal length of the exhaust pipe upstream of the exhaust gas purification device. A bent portion obtained by bending the exhaust pipe so as to change the flow direction of the exhaust gas in a part of the direction, and provided in the exhaust pipe on the inner peripheral side of the bent portion and on the downstream side in the vicinity of the bent portion, A dam member that dams the flow of exhaust gas flowing on the inner peripheral side of the bent portion and the downstream side in the vicinity of the bent portion, and is formed on the downstream side in the vicinity of the dam member, An internal combustion engine provided in the flow velocity delay region of the exhaust pipe so that the additive injected from itself passes only through the flow velocity delay region and collides with an inner wall of the exhaust pipe in the flow velocity delay region. Institutional additive dispersion system.

  Next, a third invention of the present invention is the additive dispersion system for an internal combustion engine according to the first invention, wherein the exhaust pipe has two of the exhaust pipes at the junction. After the exhaust pipes are combined, the downstream side of the exhaust pipes combined into one is connected to the exhaust purification device, and the merging portion is in the middle of one of the two exhaust pipes And the downstream end of the other exhaust pipe of the two exhaust pipes is connected, and the flow velocity delay region is one of the longitudinal directions of the upstream side of the merging portion of the other exhaust pipe. A bent portion obtained by bending the other exhaust pipe so as to change the flow direction of the exhaust gas in the portion, and formed on the inner peripheral side of the bent portion and the downstream side in the vicinity of the bent portion, From the flow rate delay region in the other exhaust pipe As Isa the additive collide with the inner wall of the other of the exhaust pipe of the flow velocity delay region only the flow velocity delay region through the provided is an additive distributed system for an internal combustion engine.

  Next, a fourth invention of the present invention is the additive dispersion system for an internal combustion engine according to the third invention, wherein the bent portion of the other exhaust pipe is formed in the vicinity of the merging portion. The flow velocity delay region is an additive dispersion system for an internal combustion engine, which is formed on the inner peripheral side of the bent portion, on the downstream side in the vicinity of the bent portion, and on the joining portion.

  Next, a fifth invention of the present invention is an additive dispersion system for an internal combustion engine according to the third invention or the fourth invention, wherein an inlet port into which exhaust gas is introduced, and an exhaust gas that is introduced into the system. An additive for an internal combustion engine, having two turbo turbines each having a discharge port for discharging the exhaust gas, the upstream sides of the two exhaust pipes being connected to the discharge ports of the respective turbo turbines It is a distributed system.

  According to the first invention, the flow velocity delay region is formed in a part of the exhaust pipe in the longitudinal direction and around the inner wall of a part of the exhaust pipe in the circumferential direction instead of the central part of the exhaust pipe. Accordingly, avoiding the central portion where the exhaust gas flow velocity is the highest and avoiding the use of the dispersion plate, the pressure loss of the exhaust gas in the exhaust pipe can be further reduced. In addition, the additive injected from the addition valve is allowed to pass through only the flow velocity delay region and collide with the inner wall of the exhaust pipe, thereby preventing the additive from flowing into the exhaust gas without colliding with the inner wall. Yes. Therefore, even when the flow rate and flow rate of the exhaust gas increase, it is possible to reliably cause the additive to collide with the inner wall of the exhaust pipe. Can be dispersed.

  According to the second invention, in the case of a single exhaust pipe, the flow velocity delay region can be appropriately and relatively easily formed by the bent portion and the weir member while suppressing the pressure loss of the exhaust gas. Moreover, an addition valve can be arrange | positioned in an appropriate position.

  According to the third aspect of the present invention, in the case of an exhaust pipe in which two exhaust pipes are connected at the junction to form one exhaust pipe, the flow velocity is delayed at the bent part while suppressing pressure loss of the exhaust gas. The region can be formed appropriately and relatively easily. Moreover, an addition valve can be arrange | positioned in an appropriate position.

  According to the fourth aspect of the present invention, when the additive injected from the addition valve collides with the inner wall of the exhaust pipe in the flow velocity delay region and is atomized, it immediately reaches the junction. Then, the atomized additive is stirred at both the exhaust gas flowing from one exhaust pipe and the exhaust gas flowing from the other exhaust pipe at the junction, Can be uniformly dispersed in the exhaust pipe.

  According to the fifth aspect of the present invention, in the internal combustion engine having the turbo turbine in parallel, the additive injected from the addition valve even when the exhaust gas pressure loss in the exhaust pipe is further reduced and the exhaust gas flow velocity and flow rate are increased. Thus, it is possible to realize an additive dispersion system for an internal combustion engine that can be appropriately atomized and dispersed appropriately in the exhaust gas in the exhaust pipe.

It is a figure explaining the schematic whole structure of the internal combustion engine to which the additive dispersion system of the internal combustion engine of the present invention is applied. It is a figure explaining the whole additive dispersion system composition of a 1st embodiment, and is an enlarged view of the II section in Drawing 1, Comprising: In the junction part in the middle of one exhaust pipe in two exhaust pipes, In the case of the exhaust pipe which connected the other exhaust pipe, it is a figure explaining the position of the flow rate delay area | region, the position of an addition valve, etc. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2, illustrating a route and the like until the additive injected from the addition valve collides with the inner wall of the exhaust pipe. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 2, illustrating an example in which the additive atomized in the flow velocity delay region is uniformly dispersed in the exhaust pipe immediately before the oxidation catalyst. FIG. 3 is a diagram for explaining a comparative example when the distance from the flow velocity delay region to the merge portion is long as compared to FIG. FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5, illustrating a route and the like until the additive injected from the addition valve collides with the inner wall of the exhaust pipe. FIG. 6 is a cross-sectional view taken along the line VII-VII in FIG. 5, illustrating an example in which the additive atomized in the flow velocity delay region is unevenly dispersed in the exhaust pipe immediately before the oxidation catalyst. It is a figure explaining the whole additive dispersion system composition of a 2nd embodiment, and is an enlarged view of the VIII section in Drawing 1, and when there is one exhaust pipe, the position of a flow rate delay area and an addition valve It is a figure explaining the position etc. It is IX-IX sectional drawing in FIG. 8, and is a figure explaining the path | route etc. until the additive injected from an addition valve collides with the inner wall of an exhaust pipe. It is XX sectional drawing in FIG. 8, and is a figure explaining the example of a mode that the additive atomized in the flow-rate delay area | region is disperse | distributed uniformly in the exhaust pipe just before urea SCR.

● [Schematic overall configuration of internal combustion engine 1 (Fig. 1)]
EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. First, a schematic overall configuration of the internal combustion engine 1 will be described with reference to FIG. In the description of the present embodiment, an engine 10 (for example, a diesel engine) mounted on a vehicle will be described as an example of an internal combustion engine. In the example of FIG. 1, the engine 10 is a multi-cylinder engine having a right bank 10R and a left bank 10L. The right bank 10R is provided with a right turbocharger 20R, and the left bank 10L is provided with a left turbocharger 20L. ing. Hereinafter, each member and the like will be described while explaining an intake path to the engine 10 and an exhaust path from the engine 10.

  The downstream side of the intake pipe 31R is connected to the intake port of the right compressor 22R of the right turbocharger 20R. The discharge port of the right compressor 22R is connected to the upstream side of the intake pipe 32R. The downstream side of the intake pipe 32R is connected to the intake port of the intercooler 30C. The right compressor 22R is rotationally driven by a right turbine 21R that is rotationally driven by exhaust gas, compresses the air taken in from the intake pipe 31R, and discharges it to the intake pipe 32R. The same applies to the intake pipe 31L, the intake pipe 32L, the left turbocharger 20L, the left compressor 22L, and the left turbine 21L, and description thereof will be omitted. Further, the upstream side of the intake pipe 31R and the upstream side of the intake pipe 31L may be combined into one.

  The intercooler 30C is provided at the junction of the intake pipe 32R and the intake pipe 32L, cools the compressed air from the intake pipe 32R and the intake pipe 32L, improves the oxygen density, and takes in the cooled compressed air. Discharge into the tube 33. A downstream side of the intake pipe 33 is connected to an intake manifold 34. The intake pipe 33 is provided with an electronic throttle device 67.

  The electronic throttle device 67 has a throttle that adjusts the opening of the intake pipe 33 based on a control signal from the control device 80, and adjusts the intake flow rate. The control device 80 outputs a control signal to the electronic throttle device 67 on the basis of the detection signal from the throttle opening detection means (throttle opening sensor not shown) and the target throttle opening to open the opening of the intake pipe 33. Can be adjusted.

  Further, a detection signal from the accelerator pedal depression amount detection means 53 is input to the control device 80. The accelerator pedal depression amount detection means 53 is, for example, an accelerator pedal depression angle sensor, and is provided on the accelerator pedal. Based on the detection signal from the accelerator pedal depression amount detection means 53, the control device 80 can detect the accelerator pedal depression amount (driver acceleration request, deceleration request) by the driver.

  The intake manifold 34 supplies intake air to each cylinder of the right bank 10R and each cylinder of the left bank 10L of the engine 10. The intake manifold 34 is connected to an EGR path for returning a part of the exhaust gas via the exhaust manifolds 41R and 41L and the pipe 35. The pipe 35 is provided with an EGR cooler 40C and an EGR valve 68.

  The EGR cooler 40C receives high-temperature exhaust gas from the exhaust inflow side that is the exhaust manifold 41R, 41L side in the pipe 35, and discharges the cooled exhaust gas from the exhaust outflow side that is the intake manifold 34 side in the pipe 35. . Cooling coolant is supplied to the EGR cooler 40C. The EGR cooler 40C is a so-called heat exchanger, and cools and discharges exhausted exhaust gas using a coolant.

  The EGR valve 68 (EGR valve) is disposed on the exhaust inflow side or the exhaust outflow side close to the EGR cooler 40 </ b> C in the pipe 35, and based on a control signal from the control device 80, the opening degree of the pipe 35 (i.e., , EGR amount).

  For example, the engine 10 is provided with a rotation detection means 52, a coolant temperature detection means 51, and the like. The rotation detection means 52 is a rotation angle sensor that can detect, for example, the rotation speed of the crankshaft of the engine 10, the rotation angle of the crankshaft (for example, the compression top dead center timing of each cylinder), and the like. The control device 80 can detect the rotation speed, rotation angle, etc. of the crankshaft of the engine 10 based on the detection signal from the rotation detection means 52. The coolant temperature detection means 51 is a temperature sensor that detects the temperature of the coolant circulating in the engine 10, for example. The control device 80 can detect the temperature of the coolant circulating in the engine 10 based on the detection signal from the coolant temperature detection means 51.

  An exhaust manifold 41R is connected to the exhaust side of the right bank 10R of the engine 10. The downstream side of the exhaust manifold 41R is connected to the upstream side of the exhaust pipe 42R. The downstream side of the exhaust pipe 42R is connected to the inlet of the right turbine 21R of the right turbocharger 20R. Exhaust gas from each cylinder of the right bank 10R is collected by the exhaust manifold 41R and guided to the right turbine 21R via the exhaust pipe 42R. The same applies to the left bank 10L, the exhaust manifold 41L, the exhaust pipe 42L, and the left turbine 21L of the left turbocharger 20L, and description thereof will be omitted. The right turbine 21R is rotationally driven by the exhaust gas flowing in from the exhaust pipe 42R, and rotationally drives the directly connected right compressor 22R. The left turbine 21L is rotationally driven by the exhaust gas flowing in from the exhaust pipe 42L, and rotationally drives the directly connected left compressor 22L.

  In the example of FIG. 1, the exhaust pipe 42L connected to the inlet of the left turbine 21L is provided with a shutoff valve 69 that opens and closes the exhaust pipe 42L. Further, the exhaust pipe 42R and the exhaust pipe 42L are connected by a communication pipe 42. The control device 80 can enable or disable the left turbocharger 20L according to the operating state by controlling the shutoff valve 69 according to the operating state of the engine 10. When the shutoff valve 69 is open, the exhaust gas from the left bank 10L is guided to the left turbine 21L via the exhaust pipe 42L. When the shutoff valve 69 is closed, the exhaust gas from the left bank 10L is guided to the right turbine 21R via the communication pipe 42 and the exhaust pipe 42R.

  The upstream side of the exhaust pipe 43R (corresponding to the other exhaust pipe) is connected to the discharge port of the right turbine 21R, and the downstream side of the exhaust pipe 43R is connected to the exhaust pipe 43L (corresponding to one exhaust pipe) at the junction 43RL. It is connected. The upstream side of the exhaust pipe 43L is connected to the discharge port of the left turbine 21L, and the downstream side of the exhaust pipe 43L is connected to the inlet of the oxidation catalyst 71. A junction 43RL is set in the middle of the exhaust pipe 43L, and the downstream end of the exhaust pipe 43R is connected to the junction 43RL. An addition valve 61 (in this case, a fuel addition valve) that injects an additive (in this case, fuel) into the exhaust gas in the exhaust pipe is disposed in the vicinity of the merging portion 43RL in the exhaust pipe 43R. Further, a bent portion 43RM formed by bending the exhaust pipe 43R is formed slightly upstream of the addition valve 61 in the exhaust pipe 43R.

  An upstream side of the exhaust pipe 45 is connected to the discharge port of the oxidation catalyst 71, and a downstream side of the exhaust pipe 45 is connected to an inflow port of a DPF 72 (Diesel Particulate Filter). The upstream side of the exhaust pipe 46 is connected to the discharge port of the DPF 72, and the downstream side of the exhaust pipe 46 is connected to the inlet of the urea SCR 73. Further, the exhaust pipe 46 is formed with a bent portion 46M formed by bending the exhaust pipe 46. A dam member 63 is provided on the downstream side in the vicinity of the bent portion 46M, and the downstream side in the vicinity of the dam member 63. Is provided with an addition valve 62 (in this case, urea water addition valve) for injecting an additive (in this case, urea water) into the exhaust gas in the exhaust pipe. The upstream side of the exhaust pipe 47 is connected to the discharge port of the urea SCR 73.

  The control device 80 includes a CPU (control unit 81) and a storage unit 82, and performs processing according to a program stored in the storage unit 82. The control means 81 receives detection signals from the various detection means described above and detects the operating state of the engine 10, and detects an EGR valve 68, a shutoff valve 69, an electronic throttle device 67, an addition valve 61, and an addition valve 62. A control signal for driving the output is output. Further, the detection means for outputting a detection signal to the control means 81 and the actuator controlled by the control means 81 are not limited to the example of FIG. 1, and various detection means (pressure detection means, exhaust temperature detection means, etc.), There are various actuators (injectors, various lamps, etc.), which are not shown and described.

  The oxidation catalyst 71 (one of the exhaust emission control devices) oxidizes carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas to make them harmless. The DPF 72 (one of the exhaust purification devices) collects particulate matter in the exhaust gas so that it is not released into the atmosphere. When the control means 81 determines that the particulate matter collected by the DPF 72 has reached a predetermined amount or more based on the operating state of the engine 10 or the like, a predetermined amount of additive (in this case, fuel) ) To cause the exhaust gas to react with the fuel in the oxidation catalyst 71. Then, the exhaust gas that has become a high temperature as a result of the reaction is discharged from the oxidation catalyst 71 and flows into the DPF 72, and the particulate matter in the DPF 72 is burned and burned to regenerate the DPF 72. If the control means 81 determines that the reduction execution condition is satisfied based on the operating state of the engine 10 or the like, the control means 81 injects a predetermined amount of additive (in this case, urea water) from the addition valve 62, and the urea SCR 73 ( The exhaust gas and urea water are reacted in one of the exhaust purification devices) to reduce nitrogen oxides (NOx) in the exhaust gas to be harmless.

  In order to efficiently incinerate the particulate matter collected in the DPF 72, the additive (in this case, fuel) injected from the addition valve 61 into the exhaust pipe 43R reaches the oxidation catalyst 71 until it reaches the oxidation catalyst 71. It is necessary to disperse the exhaust gas almost uniformly. In order to efficiently reduce NOx in the urea SCR 73, the additive (in this case, urea water) injected from the addition valve 62 into the exhaust pipe 46 is contained in the exhaust gas before reaching the urea SCR 73. It is necessary to disperse almost uniformly. Hereinafter, the first embodiment of the additive dispersion system (additive dispersion system applied to the addition valve 61 and its surroundings) and the second embodiment (the additive applied to the addition valve 62 and its surroundings). A distributed system will be described.

● [Additive Dispersion System of First Embodiment (FIGS. 2 to 4)]
2 is an enlarged view of a portion II in FIG. 1, FIG. 3 shows a III-III section in FIG. 2, and FIG. 4 shows a IV-IV section in FIG. As shown in FIG. 2, in the first embodiment, the two exhaust pipes 43L and 43R are grouped into one exhaust pipe (the exhaust pipe 43L on the downstream side of the merge part 43RL) at the merge part 43RL. After that, the downstream side of the exhaust pipe (exhaust pipe 43L on the downstream side of the merging portion 43RL) combined into one is connected to the oxidation catalyst 71 (exhaust gas purification device). The junction 43RL is set in the middle of one exhaust pipe 43L of the two exhaust pipes 43L and 43R, and the downstream end of the other exhaust pipe 43R of the two exhaust pipes 43L and 43R is connected. . As shown in FIG. 1, the upstream side of one exhaust pipe 43L is connected to the discharge port of the left turbine 21L (corresponding to a turbo turbine), and the upstream side of the other exhaust pipe 43R is connected to the right turbine 21R (corresponding to a turbo turbine). ).

  Around the inner wall of a part of the other exhaust pipe 43R on the upstream side of the oxidation catalyst 71 (exhaust gas purification device) in the longitudinal direction and a part in the circumferential direction, the flow velocity of the exhaust gas is around the surrounding exhaust gas. A flow rate delay region 90A (a region indicated by hatching in FIGS. 2 and 3) that is slower than the flow rate is formed. The flow velocity delay region 90A is bent at a bent portion 43RM obtained by bending the other exhaust pipe 43R so as to change the flow direction of the exhaust gas in a part of the longitudinal direction upstream of the merging portion 43RL in the other exhaust pipe 43R. It is formed on the inner peripheral side of the portion 43RM and on the downstream side in the vicinity of the bent portion 43RM. As shown in FIG. 2, the exhaust gas flowing in the other exhaust pipe 43R flows so as to avoid the flow velocity delay region 90A as indicated by the dotted line. That is, in the flow rate delay region 90A, the flow rate of the exhaust gas becomes slower than the flow rate of the surrounding exhaust gas, and the exhaust gas stagnates. The bent portion 43RM and the addition valve 61 are provided in the exhaust pipe on the side where the shutoff valve 69 (see FIG. 1) is not provided.

  As shown in FIGS. 2 and 3, the addition valve 61 (in this case, the fuel addition valve) has the additive 61A (in this case, fuel) injected from itself in the flow velocity delay region 90A in the other exhaust pipe 43R. , It is provided so as to pass through only the flow velocity delay region 90A and collide with the inner wall of the other exhaust pipe 43R in the flow velocity delay region 90A. The additive 61A injected from the addition valve 61 is not exposed to the flow of exhaust gas having a high speed and a large flow rate even when the engine is operated at a high speed and the exhaust gas flows at a high speed and a large flow rate. It passes only in the region 90A and reliably collides with the inner wall of the other exhaust pipe 43R in the flow velocity delay region 90A. The additive 61A atomized by collision flows into the merging portion 43RL, and flows into the merging portion 43RL from the upstream side of one exhaust pipe 43L (exhaust gas indicated by a one-dot chain line in FIG. 2). And the exhaust gas flowing from the upstream side of the other exhaust pipe 43R to the merging portion 43RL (exhaust gas indicated by a dotted line in FIG. 2). Then, immediately before reaching the oxidation catalyst 71, the stirred additive 61A (atomized additive 61A) is almost uniformly dispersed in one exhaust pipe 43L as shown in FIG.

  The bent portion 43RM in the other exhaust pipe 43R is provided in the vicinity of the merging portion 43RL. In FIG. 2, a distance L1 from the bent portion 43RM to the merging portion 43RL is, for example, a distance of about 10 to 15 [cm]. The flow velocity delay region 90A is formed on the inner peripheral side of the bent portion 43RM, the downstream side in the vicinity of the bent portion 43RM, and the merging portion 43RL. For this reason, the additive atomized in the flow velocity delay region 90A flows to the junction 43RL before being dispersed in the other exhaust pipe 43R, and the exhaust gas in one exhaust pipe 43L and the other exhaust pipe The exhaust gas in 43R is agitated. As a result, as shown in FIG. 4, the atomized additive 61A is dispersed almost uniformly in the exhaust pipe 43L downstream of the junction 43RL.

● [Comparative example for the first embodiment (FIGS. 5 to 7)]
FIG. 5 shows a comparative example in which the distance L2 from the bent portion 243RM to the merge portion 243RL is long compared to the first embodiment shown in FIG. The distance L2 is a distance of about 70 to 100 [cm], for example. 6 shows a VI-VI cross section in FIG. 5, and FIG. 7 shows a VII-VII cross section in FIG. The comparative example shown in FIGS. 5 and 6 differs from the first embodiment shown in FIGS. 2 and 3 only in that the distance L2 is long. When the distance L2 is relatively long, as shown in FIG. 7, a high concentration region AH having a high concentration of the additive 261A and a low concentration region AL having a low concentration of the additive 261A are formed, and the exhaust pipe 243L is formed. This is not preferable because the additive 261A is not uniformly dispersed in the exhaust gas inside.

  When the distance L2 is relatively long, since the distance L3 from the flow velocity delay region 290A to the merge portion 243RL is long, the additive 261A atomized in the flow velocity delay region 290A has to reach the other portion 243RL before reaching the merge portion 243RL. Are dispersed in the exhaust gas in the exhaust pipe 243R. And even if the exhaust gas (exhaust gas from the exhaust pipe 243R) in which the additive 261A is dispersed and the exhaust gas not containing the additive 261A (exhaust gas from the exhaust pipe 243L) merge at the junction 243RL, The additive is not uniformly dispersed in the exhaust gas, and as shown in FIG. 7, a high concentration region AH where the concentration of the additive 261A is high and a low concentration region AL where the concentration of the additive 261A is low are formed. End up. Therefore, as shown in FIG. 2, it is preferable to provide the bent portion in the vicinity of the merge portion.

● [Additive Dispersion System of Second Embodiment (FIGS. 8 to 10)]
8 is an enlarged view of a VIII portion in FIG. 1, FIG. 9 shows a IX-IX cross section in FIG. 8, and FIG. 10 shows a XX cross section in FIG. As shown in FIG. 8, in the second embodiment, the downstream side of one exhaust pipe 46 is connected to urea SCR 73 (exhaust gas purification device).

  Around the inner wall of a part of the exhaust pipe 46 on the upstream side of the urea SCR 73 (exhaust gas purification device) and a part of the circumferential direction, the flow rate of the exhaust gas is higher than the flow rate of the surrounding exhaust gas. A slow flow velocity delay region 90B (region indicated by hatching in FIGS. 8 and 9) is formed. The flow velocity delay region 90B includes a bent portion 46M obtained by bending the exhaust pipe 46 so as to change the direction in which the exhaust gas flows in a part of the longitudinal direction of the exhaust pipe 46, the inner peripheral side of the bent portion 46M, and the bent portion 46M. And a dam member 63 that dams the flow of exhaust gas flowing in the vicinity of the dam member 63, and is formed on the downstream side in the vicinity of the dam member 63. As shown in FIG. 8, the exhaust gas flowing in the exhaust pipe 46 flows so as to avoid the flow velocity delay region 90B, as indicated by the dotted line. That is, in the flow rate delay region 90B, the flow rate of the exhaust gas becomes slower than the flow rate of the surrounding exhaust gas, and the exhaust gas stagnates. In FIG. 8, the distance L11 from the exhaust pipe 46 upstream of the bent portion 46M to the weir member 63 is set to a distance of, for example, several [cm] to 10 [cm]. The distance L12 from the weir member 63 to the downstream end of the flow velocity delay region 90B is, for example, about 10 to 20 [cm].

  As shown in FIGS. 8 and 9, the addition valve 62 (in this case, the urea water addition valve) has the additive 62A (in this case, urea water) injected from itself in the flow rate delay region 90B in the exhaust pipe 46. , It is provided so as to pass through only the flow velocity delay region 90B and collide with the inner wall of the exhaust pipe 46 in the flow velocity delay region 90B. The additive 62A injected from the addition valve 62 is not exposed to the flow of exhaust gas having a high speed and a large flow rate even when the engine is operated at a high speed and the exhaust gas flows at a high speed and a large flow rate. It passes only in the region 90B and reliably collides with the inner wall of the exhaust pipe 46 in the flow velocity delay region 90B. The additive 62A atomized by collision is agitated by the exhaust gas flowing in the exhaust pipe 46. The stirred additive 62A (the atomized additive 62A) is dispersed almost uniformly in the exhaust pipe 46 immediately before reaching the urea SCR 73, as shown in FIG.

  In the second embodiment, by providing the weir member 63 in addition to the bent portion 46M, the flow velocity delay region 90B can be more appropriately formed. The size of the weir member 63 is set to an appropriate size by simulation or the like.

● [Effects of this embodiment]
As described above, in the additive diffusion system for an internal combustion engine described in the present embodiment, a flow velocity delay region is formed around a part of the exhaust pipe in the longitudinal direction and a part of the inner wall in the circumferential direction. The additive is collided with the inner wall of the exhaust pipe to atomize the additive. Therefore, the pressure loss of the exhaust gas can be further reduced as compared with the case where the dispersion plate is arranged in the center of the exhaust pipe where the exhaust gas flow velocity is the largest in the exhaust pipe. Further, since the additive collides with the inner wall of the exhaust pipe, there is no need to provide a dispersion plate in the exhaust pipe. In addition, since the additive injected from the addition valve passes through only the flow velocity delay region in the vicinity of a part of the inner wall in the exhaust pipe and collides with the inner wall of the exhaust pipe, even if the flow speed and flow rate of the exhaust gas increase, It can be avoided that the additive flows into the exhaust gas and does not collide with the inner wall of the exhaust pipe.

  The additive dispersion system for an internal combustion engine of the present invention is not limited to the appearance, configuration, structure, shape, etc. described in the present embodiment, and various modifications, additions, and deletions can be made without changing the gist of the present invention. It is.

  Further, the target control system to which the additive dispersion system for the internal combustion engine of the present invention is applied is not limited to the one shown in the example of FIG. 1, and can be applied to various internal combustion engines. The additive is not limited to fuel and urea water, but can be applied to an additive that is desired to be uniformly dispersed in the exhaust gas in the exhaust pipe. The numerical values used in the description of the present embodiment are examples, and are not limited to these numerical values.

10 Engine (Internal combustion engine)
10R Right bank 10L Left bank 20R Right turbocharger 20L Left turbocharger 21R Right turbine (turbo turbine)
21L Left turbine (turbo turbine)
22R Right compressor 22L Left compressor 30C Intercooler 31R, 31L, 32R, 32L, 33 Intake pipe 34 Intake manifold 35 Pipe 40C EGR cooler 41R, 41L Exhaust manifold 42 Communication pipe 42R, 42L, 45, 46, 47 Exhaust pipe 43L Exhaust pipe (One exhaust pipe)
43R Exhaust pipe (the other exhaust pipe)
43RL merging section 43RM bending section 46M bending section 51 coolant temperature detection means 52 rotation detection means 53 accelerator pedal depression amount detection means 61, 62 addition valve 61A, 62A additive 63 weir member 67 electronic throttle device 68 EGR valve (EGR valve)
69 Shutoff valve 71 Oxidation catalyst 72 DPF
73 Urea SCR
80 control device 81 control means 82 storage means 90A, 90B flow velocity delay region

Claims (5)

An additive valve for injecting an additive into the exhaust pipe of the internal combustion engine on the upstream side of the exhaust purification device, and the additive injected from the additive valve is dispersed in the exhaust gas flowing through the exhaust pipe; An additive dispersion system for an internal combustion engine,
A flow rate delay region in which the exhaust gas flow rate is slower than the surrounding exhaust gas flow rate is formed around a part of the inner wall in the longitudinal direction and part of the circumferential direction in the exhaust pipe upstream of the exhaust purification device. Has been
The additive valve is arranged so that the additive injected from the additive valve passes only in the flow rate delay region and collides with the inner wall of the exhaust pipe in the flow rate delay region.
Additive dispersion system for internal combustion engines. An additive dispersion system for an internal combustion engine according to claim 1,
The flow velocity delay region is
A bent portion obtained by bending the exhaust pipe so as to change the direction in which the exhaust gas flows in a part of the longitudinal direction of the exhaust pipe upstream of the exhaust purification device;
Provided in the exhaust pipe on the inner peripheral side of the bent portion and on the downstream side in the vicinity of the bent portion to block the flow of exhaust gas flowing on the inner peripheral side of the bent portion and on the downstream side in the vicinity of the bent portion A weir member;
And is formed on the downstream side in the vicinity of the weir member,
The addition valve is
The flow rate delay region in the exhaust pipe is provided such that the additive injected from itself passes only through the flow rate delay region and collides with the inner wall of the exhaust pipe in the flow rate delay region.
Additive dispersion system for internal combustion engines. An additive dispersion system for an internal combustion engine according to claim 1,
In the exhaust pipe, after the two exhaust pipes are combined into one exhaust pipe at the junction, the downstream side of the exhaust pipe combined into one is connected to the exhaust purification device,
The merging portion is set in the middle of one of the exhaust pipes of the two exhaust pipes, and the downstream end of the other exhaust pipe of the two exhaust pipes is connected,
The flow velocity delay region is
A bent portion obtained by bending the other exhaust pipe so as to change the flow direction of the exhaust gas in a part of the longitudinal direction on the upstream side of the merging portion in the other exhaust pipe;
And is formed on the inner peripheral side of the bent portion and the downstream side in the vicinity of the bent portion,
The addition valve is
The flow rate delay region in the other exhaust pipe is provided such that the additive injected from itself passes only through the flow rate delay region and collides with the inner wall of the other exhaust pipe in the flow rate delay region. ing,
Additive dispersion system for internal combustion engines. An additive dispersion system for an internal combustion engine according to claim 3,
The bent portion of the other exhaust pipe is formed in the vicinity of the merge portion,
The flow velocity delay region is formed on the inner peripheral side of the bent portion and on the downstream side in the vicinity of the bent portion and the merging portion.
Additive dispersion system for internal combustion engines. An additive dispersion system for an internal combustion engine according to claim 3 or 4,
Two turbo turbines having an inlet into which exhaust gas is introduced and an outlet through which the exhaust gas is introduced;
The respective upstream sides of the two exhaust pipes are connected to the discharge ports of the respective turbo turbines,
Additive dispersion system for internal combustion engines.

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