CN103114896B - Urea solution metering injector and control method thereof - Google Patents
Urea solution metering injector and control method thereof Download PDFInfo
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- CN103114896B CN103114896B CN201310066477.5A CN201310066477A CN103114896B CN 103114896 B CN103114896 B CN 103114896B CN 201310066477 A CN201310066477 A CN 201310066477A CN 103114896 B CN103114896 B CN 103114896B
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- urea
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
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- Exhaust Gas After Treatment (AREA)
Abstract
The invention discloses a urea solution metering injector which comprises a pump, a urea cylinder, a step motor and a nozzle. An outlet of the urea cylinder is connected to an entry end of the pump sequentially through a pre-filter, a first volume-variable member and a first one-way valve, a discharge end of the pump is connected to the nozzle sequentially through a second one-way valve, a second volume-variable member and a filter, and the step motor is connected to the pump. A pressure valve is disposed between the filter and the nozzle. A sensor is disposed between the nozzle and the filter. The step motor is connected with a control unit which is connected with the sensor and the nozzle. The control unit is used for controlling pressure and starting time of urea solution from the nozzle according to the speed of the step motor. Each of the pre-filter, the filter, the first one-way valve, the second one-way valve, the pump and the step motor is provided with a heating unit.
Description
Technical field
The present invention relates to a kind of solution injection apparatus and controlling method thereof, particularly a kind of urea solution metering injection apparatus and controlling method thereof.
Background technique
Diesel engine is at present by type that in the various dynamic power machines of commercial application, the thermal efficiency is the highest, capacity usage ratio is best, the most energy-conservation.But along with annual gross contamination emission continues soaring, Emissions controls extremely urgent.Diesel emission standard is to the bad components in diesel exhaust gas such as hydrocarbon (HC), and nitrogen oxide (NOX), carbon monoxide (CO) and particulate matter (PM) etc. determine limit value, and wherein nitrogen oxide is very difficult to process.At present, conventional nitrogen oxide post-processing approach comprises the methods such as selective catalytic reduction, hydrocarbon Selective catalytic reduction, nitrogen oxide absorbent device and low temperature plasma.In the application of reality, conventional take urea liquid as the urea selective catalytic reduction method of reducing agent.Selective catalytic reduction method adopts selective catalytic conversion system, the working principle of this system is: tail gas out enters outlet pipe afterwards from turbine, outlet pipe is provided with urea measuring and injecting device, spray into the urea liquid that weight ratio is 32.5%, urea generates ammonia after at high temperature there is hydrolysis and pyrolytic reaction, at catalyst surface, and ammonia and nitrogen oxide generation reduction reaction, generate nitrogen and water, thus reach the effect of cleaning of off-gas.Wherein, key technology is the flow control of urea liquid, the control of spraying and catalyzer conversion efficiency, and the flow control of urea liquid is the key ensureing catalyzer conversion efficiency.The flow control of urea liquid is the pressure being obtained urea liquid by the pressure transducer of urea liquid supply system inside, then the flow of urea liquid body is controlled by the opening time of Control Nozzle, and the principle of urea liquid supply system adopts piston structure or membrane pump structure, this structure causes the pressure amplitude of urea liquid to have very large fluctuation, especially, when small flow, the flow accurately controlling urea liquid is just more difficult.Therefore, the pressure surge effectively reducing channel interior just can contribute to the flow control accuracy improving urea liquid; Secondly, urea for vehicle solution just starts to freeze-11 DEG C time, and volume can expand about 9%, and because diesel engine or diesel-oil vehicle can work under cryogenic, therefore urea liquid supplier needs the measure taking making ice bursting by freezing.
Summary of the invention
In order to solve problems of the prior art, the object of the present invention is to provide one can reduce urea liquid supply system pressure fluctuating in inner, thus improve urea liquid flow control accuracy and low temperature resistant urea solution metering injection apparatus and controlling method thereof.
In order to achieve the above object, the present invention takes following technological scheme: a kind of urea solution metering injection apparatus, comprise pump, urea tank, stepper motor and nozzle, the outlet of described urea tank is connected to the inlet end of pump successively by prefilter, the first variable volume part and the first one-way valve, described delivery side of pump is connected on nozzle by the second one-way valve, the second variable volume part and filter successively, and described pump is connected with stepper motor; Pressure valve is provided with between described filter and nozzle; Sensor is provided with between described nozzle and filter, described stepper motor is connected with control unit, described control unit is connected with nozzle with sensor, and described control unit is used for pressure and the opening time of being carried out Control Nozzle place urea liquid by the rotating speed of stepper motor; Described prefilter, filter, the first one-way valve second one-way valve, pump and stepper motor are provided with heating unit.
A kind of urea solution metering ejection control method, is characterized in that step comprises:
1) start control unit and initialization metering system parameter, comprise pump parameter, control the parameter of electric machine, Nozzle Parameter, perform step 2 afterwards);
2) control unit reads in engine parameter by data/address bus, performs step 3) afterwards;
3) control unit obtains the temperature of urea liquid by sensor, when the temperature of urea liquid is lower than assigned temperature ﹣ 11 DEG C, then performs step 4), otherwise performs step 5);
4) control unit controls heating unit heats urea liquid and whole metering system, performs step 5) afterwards;
5) when the temperature of urea liquid is higher than assigned temperature ﹣ 11 DEG C, then perform step 6), perform step 7) afterwards;
6) close heating unit, perform step 7) afterwards;
7) control unit obtains solution pressure by sensor, when urea liquid pressure is less than 10 barometric pressure, then performs step 8), performs step 9) afterwards;
8) rotating speed increasing stepper motor makes the pressure of urea liquid be increased to 10 barometric pressure, performs step 9) afterwards;
9) when the pressure of urea liquid is greater than 10 barometric pressure, then perform step 10), otherwise perform step 11);
10) rotating speed reducing stepper motor makes the pressure of urea liquid be reduced to 10 barometric pressure, performs step 11) afterwards;
11) flow of urea liquid is calculated according to engine parameter, if the concentration Y of the nitrogen oxide in exhaust
nOXthe flow mass M of nitrogen oxide is calculated with extraction flow
eXH, then the flow mass M of nitrogen oxide
nOX=Y
nOXm
eXHif 90%NO and 10%NO2, complete reaction can fall the flow mass M of the urea liquid of nitrogen oxide
uREA=2.96M
nOX, utilize the flow mass M of urea liquid
uREAthe volume flow Q of urea liquid is calculated with density p
uREA=M
uREA/ ρ, performs step 12) afterwards;
12) flow of urea liquid required for utilization and the dutycycle of the flow rate calculation delivery nozzle of nozzle, if the flow of required urea liquid is Q
uREA, the flow L of nozzle
iNJ, then nozzle control valve dutycycle is Q
uREA/ L
iNJ, when the engine is not operating, then this method terminates, otherwise performs step 3).
After have employed technique scheme, the present invention has following beneficial effect: by arranging suitable variable volume part, can reduce the pressure surge of urea liquid supply system inside, thus improves urea liquid flow control accuracy; At low temperatures, when icing of urea solution expands, variable volume part can absorb swell increment, thus anti-locking apparatus breaks.
Accompanying drawing explanation
Fig. 1 is the structural representation of a kind of urea solution metering injection apparatus of the present invention.
Fig. 2 is the control unit flow chart of a kind of urea solution metering injection apparatus of the present invention.
In figure: 1, urea tank 2, prefilter 3, first variable volume part 4, first one-way valve 5, pump 6, second one-way valve 7, second variable volume part 8, filter 9, nozzle 10, sensor 11, pressure valve 12, control unit 13, stepper motor.
Embodiment
Below in conjunction with specification drawings and specific embodiments, the present invention is further illustrated.
As shown in Figure 1, a kind of urea solution metering injection apparatus, comprise pump 5, urea tank 1, stepper motor 13 and nozzle 9, it is characterized in that the outlet of described urea tank 1 is connected to the inlet end of pump 5 successively by prefilter 2, first variable volume part 3 and the first one-way valve 4, the output terminal of described pump 5 is connected on nozzle 9 by the second one-way valve 6, second variable volume part 7 and filter 8 successively, and described pump 5 is connected with stepper motor 13; Pressure valve 11 is provided with between described filter 8 and nozzle 9; Sensor 10 is provided with between described nozzle 9 and filter 8, described stepper motor 13 is connected with control unit 12, described control unit 12 is connected with nozzle 9 with sensor 10, and described control unit 12 is for coming pressure and the opening time of Control Nozzle 9 place urea liquid by the rotating speed of stepper motor 13; Described prefilter 2, filter 8, first one-way valve 4 second one-way valve 6, pump 5 and stepper motor 13 are provided with heating unit.
As shown in Figure 2, a kind of urea solution metering ejection control method, is characterized in that step comprises:
1) start control unit 12 and initialization metering system parameter, comprise pump 5 parameter, control the parameter of electric machine, nozzle 9 parameter, perform step 2 afterwards);
2) control unit 12 reads in engine parameter by data/address bus, performs step 3) afterwards;
3) control unit 12 obtains the temperature of urea liquid when the temperature of urea liquid is lower than assigned temperature ﹣ 11 DEG C by sensor 10, then perform step 4), otherwise perform step 5);
4) control unit 12 controls heating unit heats urea liquid and whole metering system, performs step 5) afterwards;
5) when the temperature of urea liquid is higher than assigned temperature ﹣ 11 DEG C, then perform step 6), perform step 7) afterwards;
6) close heating unit, perform step 7) afterwards;
7) control unit 12 obtains solution pressure by sensor 10, when urea liquid pressure is less than 10 barometric pressure, then performs step 8), performs step 9) afterwards;
8) rotating speed increasing stepper motor 13 makes the pressure of urea liquid be increased to 10 barometric pressure, performs step 9) afterwards;
9) when the pressure of urea liquid is greater than 10 barometric pressure, then perform step 10), otherwise perform step 11);
10) rotating speed reducing stepper motor 13 makes the pressure of urea liquid be reduced to 10 barometric pressure, performs step 11) afterwards;
11) flow of urea liquid is calculated according to engine parameter, if the concentration Y of the nitrogen oxide in exhaust
nOX(% mass ratio) and extraction flow calculate the flow mass M of nitrogen oxide
eXH(kg/hr), the then flow mass M of nitrogen oxide
nOX(kg/hr) is M
nOX=Y
nOXm
eXHif 90%NO and 10%NO2, complete reaction can fall the flow mass M of the urea liquid of nitrogen oxide
uREA(kg/hr) M
uREA=2.96M
nOX, utilize the flow mass M of urea liquid
uREAthe volume flow Q of urea liquid is calculated with density p (kg/liter)
uREA(l/h) is Q
uREA=M
uREA/ ρ, performs step 12) afterwards;
12) flow of urea liquid required for utilization and the dutycycle of the flow rate calculation delivery nozzle 9 of nozzle 9, if the flow of required urea liquid is Q
uREA(l/h), the flow L of nozzle 9
iNJ(l/h), then nozzle 9 control valve dutycycle is Q
uREA/ L
iNJ.When the engine is not operating, then this method terminates, otherwise performs step 3).
In urea tank 1, storage car is with urea liquid (32.5% weight ratio), as the reducing agent of diesel exhaust aftertreatment.Control unit 12 control step motor 13 drives pump 5 to draw urea liquid from urea tank 1, urea liquid enters the first variable volume part 3 after prefilter 2, pump 5 is entered by the first one-way valve 4, then the second variable volume part 7 is entered through the second one-way valve 6, be transported to filter 8 again, enter diesel engine exhaust system by the unlatching of nozzle 9.First one-way valve 4 and the second one-way valve 6, ensures that pump 5 is with a direction transport urea solution.
When filter 8 place urea liquid pressure is greater than preliminary election restriction pressure, pressure valve 11 is opened, and urea liquid bypass flows back to urea tank 1.
Before nozzle 9, install the sensor 10 for determining urea liquid temperature and pressure, this sensor 10 is connected with control unit 12 by signaling line.Control unit 12 carrys out the pressure of feedback control nozzle 9 place urea liquid by the rotating speed of control step motor 13.Control unit 12 decides the time of opening according to the urea liquid pressure and temperature that the sensor 10 at nozzle 9 place exports, thus the accurate flow controlling the urea liquid body sprayed.
Control unit 12 is connected with diesel engine by data/address bus, and the parameter that the flow of urea liquid provides according to diesel engine system is determined.When temperature is lower than subzero 11 degree Celsius, control unit 12 controls heating unit heats metering system.
During diesel engine work, control unit 12 works according to control strategy control step motor 13, if needed, after heating unit pretreatment, carries accurate urea liquid amount for nitrogen oxides reduction.General spraying urea liquid injection pressure is no more than 10 atmospheric pressures, the distortion being now arranged in the damping material in variable volume part can reduce pump 5 and pulse and the urea liquid pressure surge produced, make urea liquid pressure signal more stable, thus improve urea liquid flow control accuracy.
Under outage state; when temperature expands lower than subzero 11 degree of icing of urea solutions Celsius; due to the higher swelling pressure; volume reduces by compressing to make the damping material in variable volume part; select appropriate compression ratio and volume parameter; the swell increment of the icing generation of urea liquid can be made up for completely, thus prevent bursting by freezing measuring apparatus.In this case, when diesel engine starting, control unit 12 delays the startup of pump 5, after the heating system work a period of time ice in urea tank 1, start pump 5, and then supply and exhaust system carries accurate urea liquid amount.
Feature of the present invention is the first variable volume part 3 and the hollow pipeline of the second variable volume part 7(, built-in compressible material) be arranged on inlet end and the output of pump 5 respectively, and the first one-way valve 4 is connected with inlet end and output terminal respectively with the second one-way valve 6.This structure can reduce the pressure surge of the urea liquid because of pump 5 generation, makes the pressure of urea liquid more stable, thus improves the control accuracy of urea liquid flow.When icing of urea solution under low temperature expands, because pressure increase first variable volume part 3 and the second variable volume part 7 are compressed, volume reduces, and can making up for the swell increment because producing during icing of urea solution, causing measuring apparatus to break to prevent pressure from raising further.Variable volume part can select solid or hollow plastics, rubber, foam etc., and normal working temperature scope is-40 DEG C to 90 DEG C.
Compared with other dosing devices, structural type of the present invention is simple, simplifies systematic functional structrue, decreases the work of controller, thus improve reliability and the Economy of system.
Claims (2)
1. a urea solution metering injection apparatus, comprise pump, urea tank, stepper motor and nozzle, it is characterized in that the outlet of described urea tank is connected to the inlet end of pump successively by prefilter, the first variable volume part and the first one-way valve, described delivery side of pump is connected on nozzle by the second one-way valve, the second variable volume part and filter successively, and described pump is connected with stepper motor; Pressure valve is provided with between described filter and nozzle; Sensor is provided with between described nozzle and filter, described stepper motor is connected with control unit, described control unit is connected with nozzle with sensor, and described control unit is used for pressure and the opening time of being carried out Control Nozzle place urea liquid by the rotating speed of stepper motor; Described prefilter, filter, the first one-way valve second one-way valve, pump and stepper motor are provided with heating unit.
2. a urea solution metering ejection control method, is characterized in that step comprises:
1) start control unit and initialization metering system parameter, comprise pump parameter, control the parameter of electric machine, Nozzle Parameter, perform step 2 afterwards);
2) control unit reads in engine parameter by data/address bus, performs step 3) afterwards;
3) control unit obtains the temperature of urea liquid when the temperature of urea liquid is lower than assigned temperature ﹣ 11 DEG C by sensor, then perform step 4), otherwise perform step 5);
4) control unit controls heating unit heats urea liquid and whole metering system, performs step 5) afterwards;
5) when the temperature of urea liquid is higher than assigned temperature ﹣ 11 DEG C, then perform step 6), perform step 7) afterwards;
6) close heating unit, perform step 7) afterwards;
7) control unit obtains solution pressure by sensor, when urea liquid pressure is less than 10 barometric pressure, then performs step 8), performs step 9) afterwards;
8) rotating speed increasing stepper motor makes the pressure of urea liquid be increased to 10 barometric pressure, performs step 9) afterwards;
9) when the pressure of urea liquid is greater than 10 barometric pressure, then perform step 10), otherwise perform step 11);
10) rotating speed reducing stepper motor makes the pressure of urea liquid be reduced to 10 barometric pressure, performs step 11) afterwards;
11) flow of urea liquid is calculated according to engine parameter, if the concentration Y of the nitrogen oxide in exhaust
nOXthe flow mass M of nitrogen oxide is calculated with extraction flow
eXH, then the flow mass M of nitrogen oxide
nOX=Y
nOXm
eXHif 90%NO and 10%NO2, complete reaction can fall the flow mass M of the urea liquid of nitrogen oxide
uREA=2.96M
nOX, utilize the flow mass M of urea liquid
uREAthe volume flow Q of urea liquid is calculated with density p
uREA=M
uREA/ ρ, performs step 12) afterwards;
12) flow of urea liquid required for utilization and the dutycycle of the flow rate calculation delivery nozzle of nozzle, if the flow of required urea liquid is Q
uREA, the flow L of nozzle
iNJ, then nozzle control valve dutycycle is Q
uREA/ L
iNJ, when the engine is not operating, then this method terminates, otherwise performs step 3).
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| Application Number | Priority Date | Filing Date | Title |
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| CN201310066477.5A CN103114896B (en) | 2013-03-01 | 2013-03-01 | Urea solution metering injector and control method thereof |
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| CN201310066477.5A CN103114896B (en) | 2013-03-01 | 2013-03-01 | Urea solution metering injector and control method thereof |
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| CN103114896B true CN103114896B (en) | 2015-04-22 |
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| CN106050369B (en) * | 2016-06-12 | 2019-03-08 | 山东康钧环保科技有限公司 | A kind of SCR aftertreatment system urea supply device and processing method |
| DE102017201124A1 (en) * | 2017-01-25 | 2018-07-26 | Robert Bosch Gmbh | Delivery module for a dosing system for dosing a reducing agent in the exhaust system of a motor vehicle and dosing |
| CN109681297A (en) * | 2018-11-22 | 2019-04-26 | 江苏大学 | A kind of motor exhaust urea injection apparatus and its control method |
| CN109368583A (en) * | 2018-12-14 | 2019-02-22 | 深圳市车博仕机电设备有限公司 | Urea for vehicle charging machine and its use control method |
| CN111173604B (en) * | 2020-01-19 | 2021-11-19 | 无锡威孚力达催化净化器有限责任公司 | Monitoring method, device and system for urea nozzle |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2009097479A (en) * | 2007-10-19 | 2009-05-07 | Bosch Corp | Device and method for controlling reducing agent supplying device |
| JP2010007617A (en) * | 2008-06-30 | 2010-01-14 | Denso Corp | Reducing agent supply system |
| CN101737127B (en) * | 2008-11-25 | 2012-01-25 | 无锡油泵油嘴研究所 | SCP urea injection system for post treatment of diesel engine emissions |
| CN201856953U (en) * | 2010-09-30 | 2011-06-08 | 中国人民解放军军事交通学院 | Device preventing container from frost crack due to icing of urea solution |
| DE102011110056B4 (en) * | 2011-08-12 | 2022-08-11 | Vitesco Technologies GmbH | Process for dosing a reducing agent |
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