S-shaped tight coupling exhaust aftertreatment system

Abstract

The invention discloses an S-shaped tight coupling exhaust aftertreatment system, belongs to the technical field of engine exhaust, and solves the technical problem that U-shaped aftertreatment is not suitable for a supercharger with the exhaust direction facing backwards. The gas outlet end of the DOC is connected with the gas inlet end of the SCRF through a first bent pipe, the DOC, the first bent pipe and the SCRF are of a space S-shaped structure, the SCR and the ASC are integrated into an integrated structure, the gas outlet end of the SCRF is connected with the gas inlet end of the SCR through a second bent pipe, the gas outlet end of the DOC is provided with a first urea nozzle, the second bent pipe at the gas inlet end of the SCR is provided with a second urea nozzle, the gas inlet end of the DOC is provided with a first NOx sensor, and the gas inlet end of the SCRF is provided with a second NOx sensor. A first NOx sensor is arranged at the air inlet end of the SCR, a second NOx sensor is arranged at the air outlet end of the SCR, a first temperature sensor is arranged at the air inlet end of the SCRF, a second temperature sensor is arranged at the air outlet end of the SCR, and the first urea nozzle, the second urea nozzle, the first NOx sensor, the second NOx sensor, the first temperature sensor and the second temperature sensor are electrically connected with the ECU. The arrangement is more compact, and the arrangement of the whole vehicle is more facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of engine exhaust, and more particularly to an S-shaped tightly coupled exhaust after-treatment system. Background Art

[0002] The after-treatment system of National VI light vehicles (N1 / M1) mainly adopts the after-treatment layout of DOC (oxidation catalyst) + SCRF (selective catalytic reduction filter) + SCR (catalytic reduction filter) + ASC (ammonia oxidation catalyst). In order to obtain a better temperature of the catalyst, DOC+SCRF is usually tightly coupled at the outlet of the engine supercharger through a U-shaped layout, and SCR+ASC is arranged on the chassis and connected in the middle with pipes. Temperature sensors are respectively set at the front end of DOC, the front end of SCRF, the front end of SCR, and the rear end of SCR, and urea nozzles are set at the front end of SCRF and SCR.

[0003] The existing technical solution is suitable for the engine supercharger exhaust direction to be arranged forward, so there is enough space at the rear end to arrange the U-shaped aftertreatment. When the engine supercharger exhaust direction is backward, the U-shaped aftertreatment outlet design needs to make an extra turn. At this time, the entire U-shaped aftertreatment occupies a large space. The suspension and swing arm of the whole vehicle are usually designed under the catalyst, and the clearance between them does not meet the requirements (to prevent heat damage). Summary of the invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art. The purpose of the present invention is to provide an S-shaped tightly coupled exhaust after-treatment system which is more compact and more conducive to the overall vehicle layout.

[0005] The technical solution of the present invention is: an S-shaped tightly coupled exhaust after-treatment system, comprising a DOC, a SCRF, an SCR, and an ASC, wherein the DOC is installed at the outlet of an engine supercharger, the outlet end of the DOC is connected to the inlet end of the SCRF through a first elbow, and a spatial S-shaped structure is formed between the DOC, the first elbow, and the SCRF, the SCR and the ASC are integrated into an integrated structure and arranged on a vehicle chassis, the outlet end of the SCRF is connected to the inlet end of the SCR through a second elbow, the outlet end of the DOC is provided with a first urea nozzle, the second elbow at the inlet end of the SCR is provided with a second urea nozzle, the inlet end of the DOC is provided with a first NOx sensor, the outlet end of the SCR is provided with a second NOx sensor, the inlet end of the SCRF is provided with a first temperature sensor, the outlet end of the SCR is provided with a second temperature sensor, and the first urea nozzle, the second urea nozzle, the first NOx sensor, the second NOx sensor, the first temperature sensor, and the second temperature sensor are electrically connected to an ECU.

[0006] As a further improvement, the periphery of the first curved pipe is wrapped with heat insulating cotton.

[0007] Furthermore, a corrugated tube is provided in the middle of the second curved pipe.

[0008] Furthermore, two ends of the corrugated pipe are connected to the second bent pipe via flanges respectively.

[0009] Furthermore, a urea mixer is provided in the end cover of the DOC outlet end.

[0010] Further, the angle between the first urea nozzle and the airflow direction is 60-90°, and the angle between the second urea nozzle and the airflow direction is 60-90°.

[0011] Furthermore, the first urea nozzle is a water-cooled nozzle.

[0012] Furthermore, the second urea nozzle is an air-cooled nozzle.

[0013] Furthermore, the ECU obtains detection data of the first NOx sensor, the second NOx sensor, the first temperature sensor, and the second temperature sensor, and inputs the temperature model of the engine universal characteristic map to obtain control amounts of the first urea nozzle and the second urea nozzle, respectively, and controls the operation of the first urea nozzle and the second urea nozzle according to the control amounts of the first urea nozzle and the second urea nozzle.

[0014] Furthermore, the engine universal characteristic map temperature model is established as follows:

[0015] In the bench test, a third temperature sensor is provided at the air intake end of the DOC, and a fourth temperature sensor is provided at the air intake end of the SCR;

[0016] Run the engine universal characteristics once, and establish the engine universal characteristics map temperature model under the universal characteristics according to the measured values ​​of the first temperature sensor, the second temperature sensor, the third temperature sensor, and the fourth temperature sensor, without making any correction to the engine universal characteristics map temperature model;

[0017] Cancel the third temperature sensor and the fourth temperature sensor;

[0018] In actual work, the engine operating conditions are directly matched to the engine universal characteristic map temperature model, and the temperature values ​​measured at the point before the third temperature sensor and the fourth temperature sensor are cancelled are respectively found and used as the temperature of the DOC intake end and the temperature of the SCR intake end.

[0019] Beneficial Effects

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. When the exhaust direction of the engine supercharger is backward, DOC and SCRF are tightly coupled at the engine supercharger interface in S-type, which is more compact and more conducive to the layout of the whole vehicle.

[0022] 2. The urea mixer is at the DOC outlet end cover. After urea is injected, it passes through the mixer and the first elbow before reaching the SCRF inlet. The mixing distance is longer and the mixing is more complete.

[0023] 3. This system can eliminate the DOC inlet temperature sensor and the SCR air intake temperature sensor and use the engine universal characteristic map temperature model instead to reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a structural diagram of the present invention;

[0025] Figure 2 It is a schematic diagram of the structure of DOC1, the first elbow 6, and SCRF2 in the present invention;

[0026] Figure 3 System architecture diagram for establishing the temperature model of the engine universal characteristic map.

[0027] Among them: 1-DOC, 2-SCRF, 3-SCR, 4-ASC, 5-engine supercharger, 6-first elbow, 7-second elbow, 8-first urea nozzle, 9-second urea nozzle, 10-first NOx sensor, 11-second NOx sensor, 12-first temperature sensor, 13-second temperature sensor, 14-bellows, 15-urea mixer, 16-third temperature sensor, 17-fourth temperature sensor, 18-intake pipe, 19-intercooler, 20-engine, 21-high pressure EGR, 22-low pressure EGR, 23-urea injection system, 24-exhaust pipe. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the specific embodiments in the accompanying drawings.

[0029] See also Figure 1 to Figure 3, an S-shaped tightly coupled exhaust aftertreatment system, which can be applied to the engine supercharger with the exhaust direction facing forward or backward, effectively solving the technical problem that the existing U-shaped aftertreatment system is not suitable for the engine with the exhaust direction facing backward. The system includes DOC1, SCRF2, SCR3, and ASC4. DOC1 is installed at the outlet of the engine supercharger 5, and the outlet end of DOC1 is connected to the inlet end of SCRF2 through the first elbow 6. The space S-shaped structure between DOC1, the first elbow 6, and SCRF2 is more compact and more conducive to the layout of the whole vehicle. SCR3 and ASC4 are integrated into an integrated structure and arranged on the chassis of the car. The outlet end of SCRF2 is connected to the inlet end of SCR3 through the second elbow 7. The outlet end of DOC1 is provided with a first urea nozzle 8, and the second elbow 7 at the inlet end of SCR3 is provided with a second urea nozzle 9. The inlet end of DOC1 is provided with a first NOx sensor 10, and the outlet end of SCR3 is provided with a second NOx sensor 11. The air inlet end of SCRF2 is provided with a first temperature sensor 12, the air outlet end of SCR3 is provided with a second temperature sensor 13, and the first urea nozzle 8, the second urea nozzle 9, the first NOx sensor 10, the second NOx sensor 11, the first temperature sensor 12, and the second temperature sensor 13 are electrically connected to the ECU.

[0030] Compared with the existing U-type aftertreatment system, the system of the present invention eliminates the DOC inlet temperature sensor and the SCR air intake temperature sensor.

[0031] Specifically, the outer periphery of the first curved pipe 6 is wrapped with heat insulating cotton to prevent heat damage.

[0032] A bellows 14 is provided in the middle of the second curved pipe 7 to reduce the effect of vibration transmission. Both ends of the bellows 14 are connected to the second curved pipe 7 through flanges for easy disassembly and assembly.

[0033] A urea mixer 15 (using the urea mixer of the prior art) is arranged in the end cover of the gas outlet of DOC1. After the urea is sprayed, it passes through the mixer and the first elbow before reaching the SCRF inlet. The mixing distance is longer and the mixing is more complete.

[0034] The first urea nozzle 8 and the airflow direction form an angle of 60-90°, and the second urea nozzle 9 and the airflow direction form an angle of 60-90°, so as to reduce the injection resistance and ensure the mixing effect.

[0035] Preferably, the first urea nozzle 8 is a water-cooled nozzle, and the second urea nozzle 9 is an air-cooled nozzle, which can save costs while satisfying working performance.

[0036] Working principle:

[0037] The ECU obtains detection data of the first NOx sensor 10, the second NOx sensor 11, the first temperature sensor 12, and the second temperature sensor 13, and inputs the temperature model of the engine universal characteristic map to obtain the control amount of the first urea nozzle 8 and the second urea nozzle 9, respectively, and controls the operation of the first urea nozzle 8 and the second urea nozzle 9 according to the control amount of the first urea nozzle 8 and the second urea nozzle 9.

[0038] Among them, the temperature model of the engine universal characteristic map is established as follows:

[0039] In the bench test, a third temperature sensor 16 is provided at the intake end of DOC1, and a fourth temperature sensor 17 is provided at the intake end of SCR3. Figure 3 As shown (i.e., the traditional U-shaped post-processing system architecture);

[0040] Run the engine universal characteristics once, and establish the engine universal characteristics map temperature model under the universal characteristics according to the measured values ​​of the first temperature sensor 12, the second temperature sensor 13, the third temperature sensor 16, and the fourth temperature sensor 17, without making any correction to the engine universal characteristics map temperature model;

[0041] The third temperature sensor 16 and the fourth temperature sensor 17 are cancelled;

[0042] In actual work, the engine operating conditions are directly matched to the temperature model of the engine universal characteristic map, and the temperature values ​​measured at the point before the third temperature sensor 16 and the fourth temperature sensor 17 are cancelled (that is, the temperature values ​​corresponding to the third temperature sensor 16 and the fourth temperature sensor 17 on the engine universal characteristic map) are found respectively, and used as the temperature of the intake end of DOC1 and the temperature of the intake end of SCR3.

[0043] Using the engine universal characteristic map temperature model instead can reduce costs when the post-processing effect is not greatly affected.

[0044] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. An S-type close-coupled exhaust aftertreatment system, comprising a DOC (1), a SCRF (2), an SCR (3), and an ASC (4), characterized in that: The DOC (1) is installed at the outlet of the engine supercharger (5), the outlet end of the DOC (1) is connected to the inlet end of the SCRF (2) via a first elbow (6), the DOC (1), the first elbow (6) and the SCRF (2) form a spatial S-shaped structure, the SCR (3) and the ASC (4) are integrated into an integrated structure and arranged on the chassis of the vehicle, the outlet end of the SCRF (2) is connected to the inlet end of the SCR (3) via a second elbow (7), the outlet end of the DOC (1) is provided with a first urea nozzle (8), and the second elbow at the inlet end of the SCR (3) is provided with a first urea nozzle (8). The pipe (7) is provided with a second urea nozzle (9), the air inlet end of the DOC (1) is provided with a first NOx sensor (10), the air outlet end of the SCR (3) is provided with a second NOx sensor (11), the air inlet end of the SCRF (2) is provided with a first temperature sensor (12), the air outlet end of the SCR (3) is provided with a second temperature sensor (13), and the first urea nozzle (8), the second urea nozzle (9), the first NOx sensor (10), the second NOx sensor (11), the first temperature sensor (12), and the second temperature sensor (13) are electrically connected to an ECU.

2. An S-type close-coupled exhaust aftertreatment system according to claim 1, characterized in that: The periphery of the first curved pipe (6) is wrapped with heat insulation cotton.

3. The S-type close-coupled exhaust aftertreatment system according to claim 1, characterized in that: A corrugated tube (14) is provided in the middle of the second curved tube (7).

4. The S-type close-coupled exhaust aftertreatment system according to claim 3, characterized in that: Both ends of the corrugated pipe (14) are connected to the second curved pipe (7) via flanges.

5. The S-type close-coupled exhaust aftertreatment system according to claim 1, characterized in that: A urea mixer (15) is provided in the end cover of the gas outlet end of the DOC (1).

6. The S-type close-coupled exhaust aftertreatment system according to claim 1, characterized in that: The angle between the first urea nozzle (8) and the airflow direction is 60-90°, and the angle between the second urea nozzle (9) and the airflow direction is 60-90°.

7. The S-type close-coupled exhaust aftertreatment system according to claim 1, characterized in that: The first urea nozzle (8) is a water-cooled nozzle.

8. The S-type close-coupled exhaust aftertreatment system according to claim 1, characterized in that: The second urea nozzle (9) is an air-cooled nozzle.

9. The S-type close-coupled exhaust aftertreatment system according to claim 1, characterized in that: The ECU obtains detection data of the first NOx sensor (10), the second NOx sensor (11), the first temperature sensor (12), and the second temperature sensor (13), and inputs the engine universal characteristic map temperature model to obtain control amounts of the first urea nozzle (8) and the second urea nozzle (9), respectively, and controls the operation of the first urea nozzle (8) and the second urea nozzle (9) according to the control amounts of the first urea nozzle (8) and the second urea nozzle (9).

10. An S-type close-coupled exhaust aftertreatment system according to claim 9, characterized in that: The engine universal characteristic map temperature model is established as follows: In a bench test, a third temperature sensor (16) is arranged at the air intake end of the DOC (1), and a fourth temperature sensor (17) is arranged at the air intake end of the SCR (3); Run the engine universal characteristics once, and establish the engine universal characteristics map temperature model under the universal characteristics according to the measured values ​​of the first temperature sensor (12), the second temperature sensor (13), the third temperature sensor (16), and the fourth temperature sensor (17), and the engine universal characteristics map temperature model is not modified in any way; Eliminating the third temperature sensor (16) and the fourth temperature sensor (17); In actual work, the engine operating conditions are directly matched to the temperature model of the engine universal characteristic map, and the temperature values ​​measured at the point before the third temperature sensor (16) and the fourth temperature sensor (17) are respectively found and used as the temperature of the intake end of the DOC (1) and the temperature of the intake end of the SCR (3).

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