Mining diesel engine aftertreatment device and control method

Abstract

The invention provides a mining diesel engine post-treatment device and a control method, the mining diesel engine post-treatment device comprises a controller, a dry type anti-explosion treatment device, a wet type anti-explosion treatment device, a first temperature sensor, a second temperature sensor, a urea nozzle and a NOx sensor; the dry-type anti-explosion treatment device comprises a dry-type post-treatment shell, an inlet of the dry-type post-treatment shell is connected with a first exhaust pipe, and an inlet of the first exhaust pipe serves as an exhaust inlet; an outlet of the dry post-treatment shell is connected with a wet anti-explosion treatment device through a second exhaust pipe; the first exhaust pipe, the dry type post-processing shell and the second exhaust pipe all adopt double-layer shells, and heat insulation cotton is arranged between the double-layer shells; a DOC, an SCR and an ASC are arranged in the dry post-treatment shell; on one hand, the exhaust temperature can be fully utilized, and the effects of DOC and SCR are fully exerted; on the other hand, particulate matters in the exhausted gas are fully filtered through the water tank, and the exhausted gas is cooled.

Description

Technical Field

[0001] The invention relates to the technical field of diesel engine exhaust post-processing, in particular to a mining diesel engine post-processing device and a control method. Background Art

[0002] Operating machinery powered by ordinary diesel engines is a non-explosion-proof product and does not meet the safety technical requirements for operating in explosive gas environments. Because when operating in an explosive gas environment, this type of machinery does not have an explosion-proof device, and the sparks generated can easily ignite the explosive gas and cause an explosion accident. The sources of sparks are mainly three aspects: one is electrical sparks (including static sparks); the second is exhaust sparks; and the third is mechanical sparks. According to the causes of the explosion, the coal industry has formulated relevant standards and requires compliance with relevant standards for exhaust emission control of non-road machinery. Mining explosion-proof diesel engines are certified according to MT989-2006. The technical requirements for mining explosion-proof diesel engines also include engine performance parameters, emission standards, safety protection devices, etc., to ensure that the machinery can operate safely and efficiently under specific environments. The standard requires that the exhaust gas outlet temperature after the after-treatment system shall not be higher than 70°C, the surface temperature shall not be higher than 150°C; and the cooling water temperature shall not be higher than 95°C. In order to control the exhaust temperature below 70°C, an exhaust gas treatment box is installed at the outlet of the exhaust pipe, and the exhaust gas treatment box should have the function of eliminating sparks. The exhaust branch turbocharger surface is wrapped with heat-insulating material, and the wrapping should ensure that the surface temperature is below 150°C. These requirements are not conducive to the efficient operation of exhaust aftertreatment and there is a risk of early failure.

[0003] Explosion-proof exhaust systems are divided into dry explosion-proof systems and wet explosion-proof systems. The early dry explosion-proof exhaust systems were gradually replaced by wet explosion-proof exhaust systems due to the lack of exhaust gas purification function. However, with the development of technology, by adding special exhaust gas purification devices, dry explosion-proof exhaust systems also have certain exhaust gas purification functions and have become an optional option for exhaust system explosion protection. Compared with dry explosion-proof exhaust systems, wet explosion-proof exhaust systems not only have explosion-proof functions, but also have exhaust gas purification functions, so they have been more widely used. The advantages are good cooling effect, high safety, and absorption function for carbon soot in exhaust gas, and the layout space is relatively compact. However, for the exhaust after-treatment system, wet explosion-proof requires the use of water as a cooling medium for cooling, resulting in the exhaust system efficiency cannot be effectively exerted, and the DPF system cannot normally realize the passive regeneration function. Therefore, the dry explosion-proof solution is more suitable for the layout and working requirements of the exhaust after-treatment system. Summary of the invention

[0004] In order to solve at least one technical problem in the prior art, the embodiment of the present invention provides a mining diesel engine post-processing device and control method, which combines the advantages of dry explosion-proof solutions and wet explosion-proof solutions and can effectively perform exhaust explosion-proof treatment. In order to achieve the above technical objectives, the technical solution adopted in the embodiment of the present invention is: In a first aspect, an embodiment of the present invention provides a mining diesel engine post-treatment device, including a controller, a dry explosion-proof treatment device, a wet explosion-proof treatment device, a first temperature sensor, a second temperature sensor, a urea nozzle, and a NOx sensor; The dry explosion-proof treatment device comprises a dry after-treatment housing, the inlet of the dry after-treatment housing is connected to a first exhaust pipe, and the inlet of the first exhaust pipe serves as an exhaust inlet; the outlet of the dry after-treatment housing is connected to a wet explosion-proof treatment device through a second exhaust pipe; The first exhaust pipe, the dry aftertreatment housing and the second exhaust pipe all adopt double-layer shells, and heat insulation cotton is arranged between the double-layer shells; A DOC, an SCR and an ASC are arranged in the dry aftertreatment housing, and the DOC, the SCR and the ASC are arranged from upstream to downstream along the exhaust gas flow direction; The first temperature sensor is arranged upstream of the dry aftertreatment housing and is used to detect the exhaust gas temperature T4 upstream of the DOC; The second temperature sensor is arranged on the dry aftertreatment housing, downstream of the DOC and upstream of the SCR, and is used to detect the exhaust temperature T5 upstream of the SCR; The urea nozzle is installed on the dry aftertreatment housing, and the urea nozzle is located downstream of the DOC and upstream of the SCR; The NOx sensor is arranged downstream of the dry post-treatment housing and is used to detect the NOx concentration at the outlet of the dry explosion-proof treatment device; The controller includes an ACU and an antistatic box; the ACU is arranged in the antistatic box; the ACU is respectively connected to a first temperature sensor, a second temperature sensor, a urea nozzle and a NOx sensor.

[0005] Further, the first temperature sensor is located on the first exhaust pipe.

[0006] Furthermore, the NOx sensor is located at one end of the second exhaust pipe close to the dry aftertreatment housing.

[0007] Further, the urea nozzle is located downstream of the second temperature sensor.

[0008] Further, the wet explosion-proof treatment device includes a water tank, an exhaust hood, an exhaust filter box, an explosion-proof water pump, an explosion-proof water pump drive module, and an explosion-proof radiator; The exhaust filter box is installed at the bottom of the water tank, and the height of the exhaust filter box is higher than the height of the water in the water tank; a small hole for water flow is provided on the side of the exhaust filter box; an exhaust hood is installed on the top of the exhaust filter box, and the top of the exhaust filter box is connected to the inside of the exhaust hood; an airway is provided at the bottom of the exhaust hood; the second exhaust pipe extends into the water tank, passes through the exhaust hood and enters the inside of the exhaust filter box, and the lower end of the second exhaust pipe is immersed in the water in the exhaust filter box; A water circulation outlet is provided at the lower part of the side of the water tank, and a water circulation inlet is provided at the upper part of the side; the water circulation outlet is connected to an explosion-proof water pump through a pipeline, the explosion-proof water pump is connected to an explosion-proof radiator through a pipeline, and the explosion-proof radiator is connected to the water circulation inlet through a pipeline; a water temperature sensor is installed on the pipeline of the water circulation outlet; the water temperature sensor is connected to the ACU; the water temperature sensor is used to detect the circulating water temperature Tw; The ACU drives the explosion-proof water pump through the explosion-proof water pump driving module; An air outlet is also provided on the upper part of the side of the water tank.

[0009] Further, the air outlet on the upper side of the water tank serves as an exhaust outlet; or, the air outlet on the upper side of the water tank is connected to a third exhaust pipe, and the outlet of the third exhaust pipe serves as the exhaust outlet.

[0010] In a second aspect, an embodiment of the present invention provides a control method for a mining diesel engine post-processing device, comprising: After the diesel engine is started, the ACU monitors the exhaust temperature T4 and circulating water temperature Tw upstream of the DOC; when the diesel engine is just started, the explosion-proof water pump does not work; Determine whether the DOC upstream exhaust temperature T4>150℃, or the circulating water temperature Tw>40℃; if so, the ACU controls the explosion-proof water pump to start, and drives the explosion-proof water pump to work at a low load condition; if not, the explosion-proof water pump is controlled not to work; Determine whether the DOC upstream exhaust temperature T4>180℃, or the circulating water temperature Tw>50℃. If so, the ACU drives the explosion-proof water pump to work at medium-high load conditions; if not, the ACU drives the explosion-proof water pump to work at low load conditions; Determine whether the DOC upstream exhaust temperature T4>200℃, or the circulating water temperature Tw>60℃. If so, the ACU drives the explosion-proof water pump to work at a high load condition; if not, the ACU drives the explosion-proof water pump to work at a medium-to-high load condition; When the circulating water temperature Tw drops below 50°C, switch the explosion-proof water pump to operate at low load; At the same time, after the diesel engine is started, the ACU monitors the exhaust temperature T5 upstream of the SCR, and the urea nozzle does not work; when T5>urea injection temperature, the ACU obtains the SCR conversion efficiency based on T5, and calculates the required amount of urea to be injected based on the exhaust flow and the original engine NOx concentration, and controls the urea nozzle opening; the ACU obtains the measured value of the NOx concentration at the outlet of the dry explosion-proof treatment device to determine whether it meets the target requirements. If not, the ACU obtains the closed-loop correction coefficient based on the difference between the measured value of the NOx concentration and the target value, and obtains the final urea nozzle opening based on the current urea nozzle opening and the closed-loop correction coefficient, and performs PID closed-loop adjustment on the urea nozzle.

[0011] Furthermore, the low load condition of the explosion-proof water pump is 20% to 30% of the full load condition; the medium to high load condition is 50% to 60% of the full load condition; and the high load condition is more than 90% of the full load condition.

[0012] Furthermore, the urea spraying start temperature is set to 190°C.

[0013] The technical solution provided by the embodiment of the present invention has the following beneficial effects: on the one hand, the exhaust temperature can be fully utilized, the effects of DOC and SCR can be fully utilized, and the purpose of reducing gaseous pollutants in the exhaust gas can be achieved; on the other hand, the particulate matter in the exhaust gas can be fully filtered through the water tank and the exhaust gas can be cooled, which can effectively solve the contradiction between emission purification and explosion-proof cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of a mining diesel engine post-processing device in an embodiment of the present invention.

[0015] Figure 2 Schematic diagram of the water tank structure in an embodiment of the present invention.

[0016] Figure 3 4 is a flow chart of a control method in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] In the description of the embodiments of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0019] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0021] like Figure 1 As shown, the embodiment of the present invention provides a mining diesel engine post-treatment device, including a controller 1, a dry explosion-proof treatment device 2, a wet explosion-proof treatment device 3, a first temperature sensor 4, a second temperature sensor 5, a urea nozzle 6 and a NOx sensor 7; The dry explosion-proof treatment device 2 comprises a dry after-treatment housing 201, the inlet of the dry after-treatment housing 201 is connected to the first exhaust pipe 8, and the inlet of the first exhaust pipe 8 serves as an exhaust inlet; the outlet of the dry after-treatment housing 201 is connected to the wet explosion-proof treatment device 3 through the second exhaust pipe 9; The first exhaust pipe 8, the dry aftertreatment housing 201 and the second exhaust pipe 9 all adopt double-layer shells, and heat insulation cotton is arranged between the double-layer shells to ensure that the surface temperature of the first exhaust pipe 8, the dry aftertreatment housing 201 and the second exhaust pipe 9 does not exceed 150° C. when the mining diesel engine is working; A DOC, an SCR and an ASC are arranged in the dry aftertreatment housing 201, and the DOC, the SCR and the ASC are arranged from upstream to downstream along the exhaust gas flow direction; The first temperature sensor 4 is disposed upstream of the dry aftertreatment housing 201 and is used to detect the exhaust temperature T4 upstream of the DOC; specifically, it is located on the first exhaust pipe 8; The second temperature sensor 5 is disposed on the dry aftertreatment housing 201 , downstream of the DOC and upstream of the SCR, and is used to detect the exhaust temperature T5 upstream of the SCR; The urea nozzle 6 is installed on the dry post-treatment housing 201 , and the urea nozzle 6 is located downstream of the DOC and upstream of the SCR; The NOx sensor 7 is arranged downstream of the dry aftertreatment housing 201, and is used to detect the NOx concentration at the outlet of the dry explosion-proof treatment device 2; specifically, it is located at one end of the second exhaust pipe 9 close to the dry aftertreatment housing 201; The controller 1 includes an ACU and an antistatic box 101; the ACU is arranged in the antistatic box 101; the ACU is respectively connected to a first temperature sensor 4, a second temperature sensor 5, a urea nozzle 6 and a NOx sensor 7; Furthermore, the urea nozzle 6 is located downstream of the second temperature sensor 5 to prevent the injected urea solution from affecting the temperature collection of the second temperature sensor 5; Specifically, Figure 1 , Figure 2 As shown, the wet explosion-proof treatment device 3 includes a water tank 301, an exhaust cover 302, an exhaust filter box 303, an explosion-proof water pump 304, an explosion-proof water pump drive module 305, and an explosion-proof radiator 306; The exhaust filter box 303 is installed at the bottom of the water tank 301, and the height of the exhaust filter box 303 is higher than the height of the water 307 in the water tank 301; the side of the exhaust filter box 303 is provided with a small hole for water flow; the exhaust cover 302 is installed on the top of the exhaust filter box 303, and the top of the exhaust filter box 303 is connected with the inside of the exhaust cover 302; the bottom of the exhaust cover 302 is provided with an airway; the second exhaust pipe 9 extends into the water tank 301, passes through the exhaust cover 302 and enters the inside of the exhaust filter box 303, and the lower end of the second exhaust pipe 9 is immersed in the water 307 in the exhaust filter box 303; A water circulation outlet 308 is provided at the lower part of the side of the water tank 301, and a water circulation inlet 309 is provided at the upper part of the side; the water circulation outlet 308 is connected to the explosion-proof water pump 304 through a pipeline, the explosion-proof water pump 304 is connected to the explosion-proof radiator 306 through a pipeline, and the explosion-proof radiator 306 is connected to the water circulation inlet 309 through a pipeline; a water temperature sensor 310 is installed on the pipeline of the water circulation outlet 308; the water temperature sensor 310 is connected to the ACU; the water temperature sensor 310 is used to detect the circulating water temperature Tw; The ACU drives the explosion-proof water pump 304 through the explosion-proof water pump driving module 305; the explosion-proof water pump driving module 305 can specifically adopt a relay circuit; An air outlet 311 is also provided on the upper side of the water tank 301; The air outlet 311 at the upper side of the water tank 301 serves as an exhaust outlet; or, the air outlet 311 at the upper side of the water tank 301 is connected to the third exhaust pipe 10, and the outlet of the third exhaust pipe 10 serves as an exhaust outlet; The embodiment of the present invention proposes a post-processing device that combines a dry explosion-proof scheme with a wet explosion-proof scheme. The first-stage post-processing device adopts a dry explosion-proof treatment device, and the surface is heat-insulated to prevent the exhaust pipe and the package surface temperature from exceeding 150°C; the dry explosion-proof treatment device can make full use of the exhaust temperature to achieve the effects of DOC and SCR. DOC can effectively oxidize gaseous pollutants such as HC and CO in the exhaust, SCR can remove nitrogen oxides in the exhaust, and ASC can oxidize excess ammonia, so as to achieve the purpose of reducing gaseous pollutants in the exhaust gas; the second-stage post-processing device adopts a wet explosion-proof treatment device, which can use water to fully filter particulate matter in the exhaust and cool the exhaust, which not only removes particulate matter in the exhaust, but also can timely reduce the exhaust temperature to a safe temperature limit of below 70°C; at the same time, the solution of the present application also removes the DPF component, which saves costs and improves the safety of construction machinery operation; traditional DPF components are more prone to clogging or premature failure in dusty environments.

[0022] The explosion-proof water pump 304 can circulate the water in the water tank 301, and take away the heat in the water tank in time through the explosion-proof radiator 306, thereby reducing the water temperature in the water tank. The higher the speed of the explosion-proof water pump 304, the better the heat dissipation effect of the explosion-proof radiator 306. The ACU adjusts the speed of the explosion-proof water pump 304 according to the circulating water temperature Tw detected by the water temperature sensor 310, thereby adjusting its load.

[0023] In order to ensure that the exhaust temperature of the post-processing diesel engine does not exceed the requirement, the ACU is required to monitor the water temperature in real time and adjust the speed of the explosion-proof water pump to control the cooling water temperature; for this purpose, the embodiment of the present invention also proposes a control method for the post-processing device of the mining diesel engine, including the following steps: After the diesel engine is started, the ACU monitors the exhaust temperature T4 and circulating water temperature Tw upstream of the DOC; when the diesel engine is just started, the explosion-proof water pump does not work; Determine whether the exhaust temperature T4 upstream of the DOC is greater than 150°C, or the circulating water temperature Tw is greater than 40°C; if so, the ACU controls the explosion-proof water pump to start and drive the explosion-proof water pump to work at a low load; if not, the explosion-proof water pump is controlled not to work, so that the exhaust temperature can be increased as soon as possible, the SCR can enter the working state as soon as possible, and the NOx emission during cold start can be reduced; Determine whether the DOC upstream exhaust temperature T4>180℃, or the circulating water temperature Tw>50℃. If so, the ACU drives the explosion-proof water pump to work at medium-high load conditions; if not, the ACU drives the explosion-proof water pump to work at low load conditions; Determine whether the DOC upstream exhaust temperature T4>200℃, or the circulating water temperature Tw>60℃. If so, the ACU drives the explosion-proof water pump to work at a high load condition; if not, the ACU drives the explosion-proof water pump to work at a medium-to-high load condition; When the circulating water temperature Tw drops below 50°C, switch the explosion-proof water pump to operate at low load; In this embodiment, the low load condition of the explosion-proof water pump is 20% to 30% of the full load condition; the medium to high load condition is 50% to 60% of the full load condition; the high load condition is more than 90% of the full load condition; At the same time, in order to meet the exhaust emission control requirements; After the diesel engine is started, the ACU monitors the exhaust temperature T5 upstream of the SCR, and the urea nozzle does not work; when T5>urea injection temperature, the ACU obtains the SCR conversion efficiency according to T5, and calculates the amount of urea required to be injected according to the exhaust flow and the original engine NOx concentration, and controls the urea nozzle opening; the ACU obtains the measured value of the NOx concentration at the outlet of the dry explosion-proof treatment device to determine whether it meets the target requirements. If not, the ACU obtains the closed-loop correction coefficient according to the difference between the measured value and the target value of the NOx concentration, obtains the final urea nozzle opening according to the current urea nozzle opening and the closed-loop correction coefficient, and performs PID closed-loop adjustment on the urea nozzle; so that the measured value of the NOx concentration at the outlet of the dry explosion-proof treatment device meets the target requirements.

[0024] In this embodiment, the urea injection temperature is set to 190°C.

[0025] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A post-processing device for a mining diesel engine, characterized in that: It comprises a controller (1), a dry explosion-proof treatment device (2), a wet explosion-proof treatment device (3), a first temperature sensor (4), a second temperature sensor (5), a urea nozzle (6) and a NOx sensor (7); The dry explosion-proof treatment device (2) comprises a dry after-treatment housing (201), the inlet of the dry after-treatment housing (201) being connected to a first exhaust pipe (8), the inlet of the first exhaust pipe (8) serving as an exhaust inlet; the outlet of the dry after-treatment housing (201) being connected to a wet explosion-proof treatment device (3) via a second exhaust pipe (9); The first exhaust pipe (8), the dry aftertreatment housing (201) and the second exhaust pipe (9) all adopt double-layer shells, and heat insulation cotton is arranged between the double-layer shells; A DOC, an SCR and an ASC are arranged in a dry aftertreatment housing (201), wherein the DOC, the SCR and the ASC are arranged from upstream to downstream along the exhaust gas flow direction; The first temperature sensor (4) is arranged upstream of the dry aftertreatment housing (201) and is used to detect the exhaust gas temperature T4 upstream of the DOC; The second temperature sensor (5) is arranged on the dry aftertreatment housing (201), located downstream of the DOC and upstream of the SCR, and is used to detect the exhaust gas temperature T5 upstream of the SCR; The urea nozzle (6) is mounted on the dry aftertreatment housing (201), and the urea nozzle (6) is located downstream of the DOC and upstream of the SCR; The NOx sensor (7) is arranged downstream of the dry post-treatment housing (201) and is used to detect the NOx concentration at the outlet of the dry explosion-proof treatment device (2); The controller (1) comprises an ACU and an antistatic box (101); the ACU is arranged in the antistatic box (101); the ACU is respectively connected to a first temperature sensor (4), a second temperature sensor (5), a urea nozzle (6) and a NOx sensor (7).

2. The mining diesel engine post-processing device according to claim 1, characterized in that: The first temperature sensor (4) is located on the first exhaust pipe (8).

3. The mining diesel engine post-processing device according to claim 1, characterized in that: The NOx sensor (7) is located at one end of the second exhaust pipe (9) close to the dry aftertreatment housing (201).

4. The mining diesel engine post-processing device according to claim 1, characterized in that: The urea nozzle (6) is located downstream of the second temperature sensor (5).

5. The mining diesel engine post-treatment device according to any one of claims 1 to 4, characterized in that: The wet explosion-proof treatment device (3) comprises a water tank (301), an exhaust hood (302), an exhaust filter box (303), an explosion-proof water pump (304), an explosion-proof water pump drive module (305), and an explosion-proof radiator (306); The exhaust filter box (303) is installed at the bottom of the water tank (301), and the height of the exhaust filter box (303) is higher than the height of the water (307) in the water tank (301); a small hole for water flow is provided on the side of the exhaust filter box (303); the exhaust cover (302) is installed at the top of the exhaust filter box (303), and the top of the exhaust filter box (303) is communicated with the inside of the exhaust cover (302); an air passage is provided at the bottom of the exhaust cover (302); the second exhaust pipe (9) extends into the water tank (301), passes through the exhaust cover (302) and enters the inside of the exhaust filter box (303), and the lower end of the second exhaust pipe (9) is immersed in the water (307) in the exhaust filter box (303); A water circulation outlet (308) is provided at the lower part of the side of the water tank (301), and a water circulation inlet (309) is provided at the upper part of the side; the water circulation outlet (308) is connected to an explosion-proof water pump (304) through a pipeline, the explosion-proof water pump (304) is connected to an explosion-proof radiator (306) through a pipeline, and the explosion-proof radiator (306) is connected to the water circulation inlet (309) through a pipeline; a water temperature sensor (310) is installed on the pipeline of the water circulation outlet (308); the water temperature sensor (310) is connected to the ACU; the water temperature sensor (310) is used to detect the circulating water temperature Tw; The ACU drives the explosion-proof water pump (304) via an explosion-proof water pump driving module (305); An air outlet (311) is also provided on the upper side of the water tank (301).

6. The mining diesel engine post-processing device according to claim 5, characterized in that: The air outlet (311) at the upper side of the water tank (301) serves as an exhaust outlet; or, the air outlet (311) at the upper side of the water tank (301) is connected to the third exhaust pipe (10), and the outlet of the third exhaust pipe (10) serves as an exhaust outlet.

7. A control method for a mining diesel engine post-processing device, characterized in that: include: After the diesel engine is started, the ACU monitors the exhaust temperature T4 and circulating water temperature Tw upstream of the DOC; when the diesel engine is just started, the explosion-proof water pump does not work; Determine whether the DOC upstream exhaust temperature T4>150℃, or the circulating water temperature Tw>40℃; if so, the ACU controls the explosion-proof water pump to start, and drives the explosion-proof water pump to work at a low load condition; if not, the explosion-proof water pump is controlled not to work; Determine whether the DOC upstream exhaust temperature T4>180℃, or the circulating water temperature Tw>50℃. If so, the ACU drives the explosion-proof water pump to work at medium-high load conditions; if not, the ACU drives the explosion-proof water pump to work at low load conditions; Determine whether the DOC upstream exhaust temperature T4>200℃, or the circulating water temperature Tw>60℃. If so, the ACU drives the explosion-proof water pump to work at a high load condition; if not, the ACU drives the explosion-proof water pump to work at a medium-to-high load condition; When the circulating water temperature Tw drops below 50°C, switch the explosion-proof water pump to operate at low load; At the same time, after the diesel engine is started, the ACU monitors the exhaust temperature T5 upstream of the SCR, and the urea nozzle does not work; when T5>urea injection temperature, the ACU obtains the SCR conversion efficiency based on T5, and calculates the required amount of urea to be injected based on the exhaust flow and the original engine NOx concentration, and controls the urea nozzle opening; the ACU obtains the measured value of the NOx concentration at the outlet of the dry explosion-proof treatment device to determine whether it meets the target requirements. If not, the ACU obtains the closed-loop correction coefficient based on the difference between the measured value of the NOx concentration and the target value, and obtains the final urea nozzle opening based on the current urea nozzle opening and the closed-loop correction coefficient, and performs PID closed-loop adjustment on the urea nozzle.

8. The control method of the mining diesel engine post-processing device according to claim 7, characterized in that: The low load condition of the explosion-proof water pump is 20% to 30% of the full load condition; the medium to high load condition is 50% to 60% of the full load condition; and the high load condition is more than 90% of the full load condition.

9. The control method of the mining diesel engine post-processing device according to claim 7, characterized in that: The urea spraying temperature is set to 190°C.

Images