JP2003529011A - Method and composition for ensuring reduction of NOx emissions from an engine by selective catalytic reduction - Google Patents

Abstract

(57) The invention provides an SCR system that is reliable for reducing NO _x emissions from lean-burn internal combustion engine (10). The system includes using a chemical labeling reagents to ensure proper use of urea or other of the NO _x reducing reagent (30). The labeled reagent is detected, in order to demonstrate _the NO _x reduction reagent (30), reagent quality sensor (52) is provided. Sensor (52), preferably, determines the feed rate to ensure proper _the NO _x reduction reagent feed rate, thus can be used to prevent supply shortage or oversupply and empty Disruption of supply due to tanks or clogged supply lines can be warned.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention _x Exhaust
Improving the reliability of selective catalytic reduction (SCR) systems to reduce
Related. [0002] Diesel engines and lean-burn gasoline engines are known for their fuel economy.
And brings advantages, but NO during normal operation _x And particulates. Main measurement
Constant (influences the combustion process itself, eg, exhaust gas circulation and engine timing adjustment)
Effect) to decrease one, usually the other increases. So
Selected to reduce pollution from particulates and obtain good fuel economy
The combustion condition is NO _x Tend to increase. [0003] Current and proposed regulations provide manufacturers with good fuel economy and fine particulate matter.
And NO _x Is required to be reduced. The lean-burn engine is fuel
Although it may be necessary to achieve economic objectives, the high concentration of oxygen in the exhaust
, A typical exhaust gas catalyst system is NO _x Helpless to reduce. [0004] SCR (Selective Catalytic Reduction) is a process in which NO _x To selectively reduce
For its ability to utilize reagents that can be used economically. This is a fixed source
Has been used for many years to reduce NOx emissions from
Is becoming a strong candidate for However, for the widespread adoption of this technology
One potential hurdle is that, from a regulatory perspective, this system will work effectively.
There must be some means to ensure that Other har
Dollar is NO on a continuous and real-time basis _x It is not possible to measure exhaust
It is a fact to say. [0005] For automotive diesel engines and other lean-burn engines, S
Current status of valid responses to regulatory and practical hurdles accompanying CR
There is a need for. [0006] NO from diesel engines _x SCR catalysts are used to limit emissions
The risk of ammonia must be dealt with or the risk of catalyst contamination is satisfactory
Must be processed to be able to. Address the safety issues associated with ammonia
To assemble, aqueous urea or other liquid reagents have been proposed. In this regard
, R.A. J. Hulterman; "Diesel engine using urea injection
Catalytic reduction of NOx from coal (A Selective Catalytic
Reduction Of NO _x from Diesel Engine
s Using Injection of Urea) "; Doctoral Dissertation 1995
Sep., SAE No. 970185, entitled "Low Emission High Power Diesel Engine"
Transient Performance of Urea DeNOx Catalyst
ce of a Urea DeNO _x Catalyst for Low
Emissions Heavy-Duty Diesel Engines)
No. 5,431,893 to Hug et al .; WO 97/01387.
And European Patent Application No. 487,886 A1. These documents and below
The references cited are incorporated herein by reference in their entirety. [0007] Each of these literature precautions, especially regarding sources of movement, has a broad
This must be taken into account when developing a commercial SCR system that can be used.
Furthermore, from a regulatory point of view, the NO. _x Equipped with a reducing agent
There is a problem how to guarantee that. This reagent is expensive
Requires or uses low-cost non-regulatory reagents for operators
There will always be a motive for not refilling. [0008] The art recognizes the use of urea or other effective reagents in SCR processes.
NO _x There is a long-awaited need to develop methods, devices and compositions that guarantee the use of reducing reagents.
I have. SUMMARY OF THE INVENTION An object of the present invention is to provide a NO. _x Reliable for reducing emissions
To provide an SCR system. Yet another and more specific object of the present invention is to operate, if not effectively prevent, an operating system.
The use of urea in SCR systems to stop tars from frustrating
It is to be. Yet another and even more specific object of one embodiment of the present invention is to provide an operator
Engine management system (EMS) to stop or prevent the setback
By enabling the use of urea in SCR systems that enable integration with
is there. [0012] Yet another particular object of the present invention is to monitor and maintain the quality of a urea solution.
Is to provide a simple mechanical device. [0013] Yet another particular object of the present invention is to sense the decline in reagent quality, _x System
Switch to the policy, continuous NO _x Providing a control system that guarantees return
It is. [0014] Yet another object of the present invention is to provide a specially designed urea solution,
NO other than urea, including hydrocarbon liquids such as coal, etc. _x Same for reducing reagent
It is to provide a system that can be used with such advantages. [0015] Yet another object of the present invention is to provide a method, _x Guarantees reducing reagent supply speed
In order to determine the supply rate for
Supply that can be used and due to empty tanks or clogged supply lines
Is to provide a system that can warn of the destruction of a vehicle. It is yet another object of the present invention to provide a novel arrangement for the physical and / or physical use of fluorometric techniques.
NO in combination with chemical testing _x Detect attempts to avoid control, preferably spontaneous
By providing appropriate incentives for obedience to obedience,
It is an object of the present invention to provide a system that achieves the above and other objects. [0017] These and other objects are attained by: _x Ensuring the reliability of reduced SCR systems
This is accomplished by the present invention which provides improved methods, compositions and devices for The present invention relates to NO _x NO of predetermined quality in reduction system _x Reducing reagent
The presence of at least one fluorescent tracer and / or
Testing the reagent solution for concentration, a sensor signal indicating the presence of a chemical tracer
Signal, comparing this sensor signal with a reference value, the result of this comparison
Generating a control signal representing the flow rate of the urea solution in response to the control signal.
Providing a method comprising: Other parameters, such as reagent levels, may be determined by fluorometry, physical means and / or
Can also be monitored by chemical means and used to facilitate control
be able to. In a preferred embodiment, if the quality of the urea solution does not pass the test, non-compliance
The injector is closed to prevent operation with the solution. In this way,
An engine or other control system can alert the operator and
Or without the use of reagents, e.g. exhaust gas recirculation, engine timing
Engine operation by lowering it to produce less power or less power.
NO _x Will control to maintain the level. This system is preferably
Alerts the operator of the potential reduction in power and allows the operator to resume normal operation.
Before opening, it will be required to replace the reagents with standard reagents. In one embodiment, the device includes a N source including a radiation source within a defined wavelength range.
O _x Reducing reagent quality sensor, NO _x The reducing reagent is supplied to an exhaust system including an SCR reactor.
Supply means for supplying to the system and NO _x The article for controlling the supply of a reducing reagent.
Control means responsive to the quality sensor is included. The composition according to the invention comprises NO _x Effective reagents for reduction and defined waves
Chemical tracers that fluoresce when exposed to radiation within a long range are included. Like
In a preferred embodiment, the composition also comprises a special coating used by the composition.
Special catalyst manufacturers to ensure that they do not contain contaminants for the medium
Thus it will give a designed chemical tracer. DETAILED DESCRIPTION OF THE INVENTION In this description, the term “engine” is used broadly to refer to liquid or gaseous hydrocarbons.
Burning fuel, for example, directly or indirectly to mechanical or electrical energy
It is meant to include all combustors that provide heat to convert to. Otto
, Diesel and turbine type internal combustion engines and burners and furnaces,
Benefit from However, diesel engines and lean-burn engines
Gin, reliable NO _x Highlights the issues and benefits of successful achievement of reduction
These engines will be used for the purposes of the examples throughout this description.
Is done. Fixed and mobile engines are contemplated. In this description, the term “lean-burn engine” refers to the hydrocarbon fuel chemistry.
Inlet oxygen concentration greater than required for stoichiometric (or chemically accurate) combustion
For example, an engine capable of operating with an excess of at least 1% by weight of oxygen
Is meant to be included. The term “diesel engine” refers to both mobile (including marine) and stationary power units.
2 strokes per cycle, 4 strokes per cycle and rotary
It is meant to include all compression ignition engines of the type. The term “hydrocarbon fuel” refers to those produced from “distillate fuel” or “petroleum”
Is meant to include all of the fuel. Gasoline, jet fuel, diesel
Fuels and various other distillate fuels are included. The term "distillate fuel" refers to petroleum or stone
All of these products produced by distillation of oil fractions and resids are meant. the term
"Petroleum" is in its ordinary sense, irrespective of the feedstock normally included within the meaning of this term
To include all of these materials, regardless of viscosity, including hydrocarbon materials.
This is recovered from fossil fuels, especially gaseous fuels such as methane,
Including lopan, butane, etc. The term “diesel fuel” conforms to ASTM diesel fuel or other definitions
"Distillate fuels", including diesel fuels,
But not alcohols, ethers, organic nitro compounds, etc.
Knol, ethanol, diethyl ether, methyl ethyl ether, nitromethane
) May be included. Also, corn, purple coconut palm, shale and coal
Emulsions and liquid fuels derived from plant or mineral resources such as
Is within the range. These fuels also include dyes, cetane modifiers, 2,6-di-t
antioxidants such as tert-butyl-4-methylphenol, corrosion inhibitors,
Rust inhibitors such as killed succinic acid and anhydride, bacterial growth inhibitors, rubber inhibitors (g
um inhibitor, metal deactivator, upper cylinder lubricant, deicing agent, etc.
Other additives known to those skilled in the art may be included, including The term “NOx reducing agent” is useful for this purpose, especially in liquid form
All that can be stored at, for example, diesel fuel or its components
Linear and branched aliphatic and mixtures thereof, such as any one or more of the foregoing.
And / or hydrocarbons such as aromatic hydrocarbons, aromatic compounds such as toluene, meta
Fats such as lower aliphatic alcohols such as knol, ethanol and propanol
Oxygenated hydrocarbons containing group III compounds and urea and aqueous ammonia (NH ₄ OH)
It is meant to include such nitrogenous materials. The term “urea” refers to ammelide, ammelin
ine), ammonium carbonate, ammonium bicarbonate, ammonium carbamate
, Ammonium cyanate, ammonium salts of inorganic acids, organic acids including formic acid and acetic acid
Ammonium salts, biuret, cyanuric acid, isocyanic acid, melamine and triamine
Includes urea in all of its commercial forms, including those containing cyanourea
Is meant to be. Typically, commercial forms of urea contain more than 95% urea
Urea or an aqueous solution containing urea of this purity. An aqueous solution of urea can be used up to its solubility limit. Typically this
Aqueous solutions contain about 2 to about 65% reagent, by weight of the solution.
Would. A typical concentration of urea is about 25 to about 50%, for example, about 30 to about 35%.
%. Preferred concentrations for mobile applications advantageously involve urea precipitation.
32.5% urea showing the lowest freezing point. The urea or other reagents according to the invention are liquid in final form for use (urea field).
Aqueous solution), and within the specified wavelength range, preferably
Is at least one tracer that fluoresces when exposed to radiation in the visible range.
Will be contained. This fluorescent tracer is approximately 200 to 850 nanometers.
Excitation wavelength range and fluorescence from about 205 to 855 nanometers (nm).
It is preferably characterized by a "force" range. Non-interfering in this fluorescent compound
Functional groups (sulfonate, hydroxyl, carboxylate, amino, amide, etc.
) May be present. Aromatic rings may be present. Desirably, the excitation wavelength and the fluorescence emission wavelength will be different. One of this kind
A suitable example of one preferred material is Rhodamine B, CAS No. 81-88-9.
This material can be excited at a wavelength of 554 nm (green) and can be excited at 580 nm (yellow).
Color). Rhodamine 6G is excited at 530 nm (green) and 590 n
Light is emitted at a wavelength of m (yellow). Another preferred fluorescent chemical tracer is 1,5-naphthalenedisulfonic acid (ND
SA) (excitation: 290 nm, emission: 330 nm), but have achieved various objects of the present invention.
A wide variety of fluorescent and other tracers or indicators to generate
Can be used. Yet another is 400n when excited at 365nm.
m is a pyrenetetrasulfonic acid (PTSA) that emits light. This tracer is also a well-known nonylphenol ethoxylate surfactant
It may be. In particular, the fluorescent surfactant is octylphenol ethoxylate
, Dialkylphenol ethoxylates and alkylnaphthylene ethoxylates
It is something like Although not desirable, the temperature of the processing solution sent to the nozzle
If the degree is exceptionally high (this temperature is preferably kept below 100 ° C.)
Very heat resistant fluorescent surfactants as described above would be used. Of course, the interface
Instead of being an activator, a separate fluorescent tracer can be used.
Of course, if surfactants are present, interference is avoided or minimized and fluorescence is distinguished.
Care must be taken to be sufficiently different to be done. To achieve a number of objects of the present invention, other chemical tracers or indicators
-, Dye and transition metal-containing ion (colorimetric analysis), NO _x Inert in processing solution
Wide range including certain metal cations and anions (with ion-selective electrode as device)
From a variety of chemicals. Also, for example, chemistry and application updates
For further discussion, see US Pat. No. 5,132,096 and US Pat. No. 5,277.
See also No. 185. 2 or 3 or more differential tracers (analytical
Can be used). For the selection of the fluorescent tracer in terms of the possible high temperature of the processing solution,
is there. High temperatures can cause decomposition of tracers such as the ethoxylates described above.
There will be. In the case of urea, sometimes in a mixer or before transport to a spray nozzle
It is advantageous to heat the urea solution above the boiling point at some other point,
Can happen-in some cases this may happen due to a process failure
. This will aid in the hydrolysis of urea, which will be an effective reaction product. this
The temperature may be as high as 100 to 300 ° C. The pressure in this case is
If so, it must be raised enough to maintain a single phase solution. So
High temperature or strong shear before the processing solution reaches the point of introduction into the exhaust
In these cases where one would expect to encounter force, one would have to use a high
In each case heat and shear resistant tracers can be used. Alkylpheno
Ethoxylates are thermally stable and meet the requirements of inert tracers
At low temperatures, these compounds can be used to monitor and / or control reagent delivery.
Would be suitable. [0036] In a preferred embodiment, the composition also comprises a composition used by the composition.
Special catalyst manufacturers are required to ensure that they do not contain contaminants for other catalysts.
Will give a chemical tracer designed by car. Deicing substance and fog
Other reagents (eg, alkylphenol ethoxylates) to enhance
Use a surfactant which may be etc., and make the injector deposit-free
It may be useful to maintain Also, a sensor for the tracer
To keep the sensor clean and efficient when kept in the tank
In addition, it may be useful to use detergents or other reagents. FIG. 1 schematically illustrates a preferred embodiment including the present invention and its advantages. Simply saying
Thus, the diesel engine 10 has a line 12 and an injector 13
Fuel is supplied. Engine is NO _x To produce an exhaust gas containing
It passes through the exhaust pipe 20. The urea solution is transferred from container 30 to one or more
The fuel is supplied to the exhaust line 20 by such an injector. Next, the exhaust gas is S
It passes through the CR reactor device 34. This step is preferably separated in other cases.
Equipment that can be integrated or integrated with an engine management system (EMS)
By means of a controller 40, known as a board diagnostics device (OBD)
Is controlled. In an embodiment not shown, the urea solution is connected to the exhaust valve of the engine.
It is introduced into the exhaust gas with an SCR (selective catalytic reduction) device 34. FIG. 1 illustrates sharing with a return to the supply via a supply line, for example, a spill line 33.
1 shows a reagent injector system using a passage rail 31. This system is
A continuous flow of reagent between the storage container 30 and the injector 32 is maintained. the term
The term “injector” as used herein refers to the urea solution from the rail 31 to the exhaust gas.
Used to describe all devices that can control liquid flow.
The injector may be a high pressure device or a low pressure device, as described in more detail below.
It may be a chair. In particular, low pressure devices are used to inject liquid fuel for internal combustion engine applications.
Used type of mechanical atomizer, spray paint, sonic atomizer, fine
Tube having a dispersing device including a plurality of orifices to provide a spray
Commercial low pressure liquid distribution means, such as a simple valve or pintle control nozzle extending to
It is all. Preferred injectors of this type are from about 10 to about 100 psi.
g, for example, will be operated at a reasonably high pressure of about 30 to 50 psig
. High pressure devices can also be used. Pneumatic nozzles can be used,
It is preferable to operate it with minimal air to reduce the cost of the equipment.
The air has the effect of cooling the exhaust. Air supply and its cooling effect are acceptable
In situations where there is no design compromise, cool the injector and / or inject urea solution.
Air cannot be used to aid entry. One preferred form of injector is a rice injector filed on October 1, 1998
National Patent Application No. 09 / 164,304, entitled "Fluid Cooled Injector"
Is shown in This injector has a pintle controlled injection orifice
The impact plate is provided directly outside the orifice,
The laye hits this plate and is rapidly becoming finely dispersed. This image
Use solenoids to electrically operate the actuators and other preferred forms
be able to. It is possible to control both the frequency of opening and the duration of all opening positions.
Wear. The percent open time may conveniently be from 0 to 80%. Frequency is stool
Advantageously, it can be between 5 and 30 Hertz. Understand that a wide range of other values can be used
Will be done. Injector control is very flexible and transient engine
It is an object of the present invention to be very quick to facilitate quick adjustment to operating conditions.
Is an advantage. Particularly when using low pressure injectors, a good distribution of the urea solution in the exhaust gas
Preferably, in-line mixing means are used to ensure distribution. Distribution is high
Concentrated urea solutions cause localized cooling, which can be caused by droplets of water or urea or heat.
This is important because particles of the decomposition products will remain and will subsequently collide with the SCR catalyst.
You. One suitable device is shown as propeller 46. Instead, perforated bodies, mi
Has strike remover, static mixer, particle trap or other mixing capacity
Similar devices can be used. FIG. 1 also shows liquid or solid urea or
Works as a protective device against urea residue coming into contact with the catalyst in SCR reactor 34.
1 shows a bend 21 in an exhaust pipe 20 for use. The embodiment shown in FIG. 1 includes a rail pressure sensor 35 and a pressure regulating valve 36.
Have been. The pressure in the rails and return lines is provided by controller 40.
In response to a control signal being provided, by a valve 36 and a pump 37. Pressure lines 31, 31
'And 31 "are shown in the figure from the unpressurized return lines 33 and 33'.
It should be noted that the color is also shown in black. Optionally, a urea solution if overheated
To cool or heat it when the ambient temperature is very low.
0 can be used in line 33. The line between the pump 37 and the container 30
Steps 38 and 38 'provide agitation to the urea solution when needed. The following functions are available: reagent level measurement, reagent temperature sensing, reagent quality sensing,
Flow control in tank 30 to implement one or more pumps, heaters
And housing the sensor module is possible and in some cases desirable
. Modules of this type are equipped with one or more
Can be connected to Troller. Controller 40 preferably addresses the need for several different controllers.
To avoid and use existing wiring harnesses and sensors to the extent possible.
It is integrated with the EMS for the engine 10. Different sensors are shown and different
Function that senses driving parameters and generates driving signals that represent the sensed parameters
Fulfill. The operating signal is then sent to the controller, which
Is compared with a reference value, one or more control signals are calculated, and the control signals are controlled.
To one or more devices. FIG. 1 shows a sensor 41 for an engine, a sensor 42 for an exhaust gas temperature, and a container 3.
0 for the temperature of the urea solution in the return line 33 and the sensor 43 for the urea level in 0
The sensor 44 is shown. Fuel flow, engine speed, throttle position or injection
By one or more appropriate parameters, such as configuration
The engine load as expressed is an important parameter and one or more of these
Monitor similar factors and generate NO _x Volume and supply of reagent to heating device
It is possible to determine the nature or its hydrolysis products supplied to the exhaust gas. Residual
Any sensor, such as the sensor 45 for NOx concentration, can be used
It can be used for feedback control to a certain extent. The figure shows
Also, the dotted line indicates the operation signal sent to the controller and the device being controlled.
5 shows a control signal to be sent. The temperature of the urea solution throughout the system is increased to such an extent that solids precipitate.
A value low enough that water splitting is not allowed at elevated temperatures for a sufficient amount of time
(For example, about 140 ° C. or lower). The injector 32
For engines, the temperature of the exhaust gas is about 300 to 650 ° C under high load after starting.
When it rises to within the range, it tends to become hot. If you are not vigilant, high temperatures
Prior to injection, hydrolysis of urea occurs, and the hydrolysis products are smaller than urea.
It will cause precipitation due to solubility. According to the present invention, the urea solution is
Continuously circulating through channels 31 and 33 (and associated lines when controlled)
Ring to provide cooling to injector. The system for the temperature involved
When pressurized to a saturated vapor pressure of
It is practical with proper control. Because the residence time on the spill line is short,
The urea solution without reaching the solubility limit for the hydrolysis product,
Higher temperatures can be reached. Auxiliary heating is used to reach the desired temperature.
Heating means (not shown) is placed somewhere in the container 30 or in the supply or return system.
Can be used. Line 33 is an embodiment in which another cooling means is provided for the injector.
Can be deleted. Reagent quality sensor 52 is conveniently connected to supply line 38 '.
Placed in The exact properties of this sensor 52 will depend on the reagent selected, but preferably
Light emitting diode of suitable color to excite fluorescent indicator and emitted
A photodiode for sensing light, converting a received light signal, and converting it to an electrical control signal
Will include an Aether Receiver. For example, if the reagent is rhodamine B,
And emit at 580 nm, which can be used to excite rhodamine B, AND
Green light emitting diodes (typically manufactured by And Inc.)
554 nm) can be used. According to another procedure, a sample is taken from line 38 ′ and supplied to analyzer 52.
. In the example of analyzing a fluorescent tracer, the analyzer is generated by the light source therein.
A substance that is transparent to the light that emits light, for example, a quartz cylinder or tube
Can be characterized by This light source is a fluorescent field as disclosed below.
Operates at the required wavelength to excite a surfactant or other fluorescent tracer compound
Will. To excite (provide energy to) a fluorescent compound, actinic radiation
Other forms can be used. Emitted by or from the activated sample at a 90 ° angle from the light source
Fluorescence as an analog of the tracer concentration, so that the urea concentration is an example.
DC voltage, DC ampere, pulse frequency, etc.
There are transducers that convert to good signals. Conversion and analog signal generation
For example, US Pat. Nos. 4,992,380 and 5,041,
No. 386. This analog signal is NO _x Used to control the device that supplies the reducing reagent
Will be. This analog signal can also be separated in this way in several ways.
It can be used to make an intelligent record of the analyzed chemical processing concentration. Then use the standard concentration for the fluorescent tracer for the urea concentration.
Low concentration, oversupply or emptying or subject to flow interruption by
The system to test for the absence of reagents due to
Can be. Process pumped to a suitable injector or spray nozzle
A sample of the solution (in line 38 'or at another convenient location) was used to generate the fluorescence intensity.
Can be excited at the required wavelength. About the sample made in this way
The intensity of the fluorescence from each sample is compared to the known intensity of the calibration standard (eg,
Can be done at Then, by comparison, the treatment solution is treated as a term for the concentration of the treatment agent.
An eye can determine how to compare to the standard. By such a comparison
The feed rate may vary more or less in terms of active reactant (product) concentration.
You can decide whether to get it or leave it. This comparison is
It may be missing or continuous. The concentration of the fluorescent tracer, eg, in parts per million, of the tracer is
Because of the dilution water added to the concentrated chemical treatment solution containing the racer,
The fluorescence concentration of the sample is determined by comparing the standard (eg, 1.0 ppm tracer)
When considered (taken) as%, it decreases proportionally. Chemical treatment (effective reagent)
The degrees vary in the same way. When looking at low concentrations, increase the flow rate proportionally
Or stopping the flow and different NO _x Including switching to control mode
There are several possible control answers. This also prevents or prevents unauthorized dilution with distilled or deionized water.
Can be used to stop. This also raises questions such as the evolution of ammonia.
An oversupply that can cause problems can be detected. The controller 40 avoids the need for several different controllers and allows
To take advantage of existing wiring harnesses and sensors to the extent, engine 10
EMS. Instead, the necessary features for SCR
A dedicated controller including dedicated sensors or where possible
Can be used by sharing with MS. Different sensors are shown, which are different
Senses driving parameters and generates a driving signal indicating the sensed parameters.
Perform the function. Then, the operation signal is sent to the controller, and the controller
Compare these with the reference value, calculate one or more control signals and control the control signals
To one or more devices. [0055] In response to the control signal, the flow rate of the urea solution may cause it to be injected and / or supplied.
Remove from supply line or remove it into exhaust gas at a speed sufficient for SCR
It is controlled to inject and pass exhaust gases through the SCR reactor. Monitoring other parameters such as pressure in the vessel and / or supply line;
Can be used to facilitate control. What of these control parameters
Or all of them, by dedicated signal processor or comprehensive engine parameters
-Processed by the main engine controller, which may have the direct advantage of referencing the map.
Can be Preferred compositions include, when used, diluent water (eg, non-deionized water).
The scale control composition is included when necessary to combat the hardness in
Would. Also, to ensure proper flow and that there is no deposition on the sensor,
Cleaners and surfactants can be used. A basic advantage of the present invention is that it checks for the presence of the required level of high quality reagents.
In addition, some contaminants are sensed, creating part of the control configuration in addition to the fluorescent agent.
It is possible. Other parameters such as reagent levels and / or presence of contaminants
Data should also be monitored by fluorometric, physical and / or chemical means
Can be used to facilitate control. For example, chlorine
It is harmful to the catalyst and can be subject to control. For example, one implementation
The form may be a sensor for detecting the presence of harmful chlorine concentrations, such as an ORP pro
Probe (redox potential measuring the potential of chlorine species on the surface of the noble metal electrode vs. the reference electrode)
I will provide a. Some operators may try to dilute standard reagents in tap water
This is important because you can't. This reduces the reagent concentration reaching the catalyst
In addition, it gives chlorine to it and will probably impair its long-term function
. Chlorine will have many deleterious effects. This includes the catalyst canister
Corrosion of the exhaust system, which degrades the catalyst support, and which evaporates the catalyst metal
Atmospheric pressure will be reduced. In addition to chlorine, other potentially important pollutants are phosphorus, lead, arsenic, zinc,
Sulfur, vanadium and oily components that may reduce the effectiveness of the sensor
You. In a preferred embodiment, a heater is provided to maintain the temperature of the urea solution
. Thus, the present invention _x NO of predetermined quality in reduction system _x A method for assuring the presence of a reducing reagent, the presence of at least one fluorescent tracer.
Testing the reagent solution to generate a sensor signal that indicates the presence of a chemical tracer.
Generating, comparing this sensor signal to a reference value, representing the result of this comparison
Generating a control signal and controlling a flow rate of the urea solution in response to the control signal.
And a method comprising: In a preferred embodiment, if the quality of the urea solution fails the test,
Close the injector to prevent operation with the immersed solution. In this way,
The engine or other control system can alert the operator and
Preferably, without the use of reagents, for example, exhaust gas recirculation, engine timing
Engine operation by reducing engine power or reducing output.
No _x Will control to maintain the level. This system is preferably
Alerts the operator of the potential reduction in power and allows the operator to
Before resuming, it will be required to replace the reagents with standard reagents. others
Several preferred logic diagrams for this are shown in FIGS. [0062] In one embodiment, the apparatus includes a N source including a radiation source within a defined wavelength range.
O _x Reducing reagent quality sensor, NO _x The reducing reagent is supplied to an exhaust system including an SCR reactor.
Supply means for supplying to the system and NO _x The article for controlling the supply of a reducing reagent.
Control means responsive to the quality sensor is included. The composition according to the invention comprises NO _x Effective reagents for reduction and defined waves
Chemical tracers that fluoresce when exposed to radiation within a long range are included. Like
In a preferred embodiment, the composition also comprises a special coating used by the composition.
Special catalyst manufacturers to ensure that they do not contain contaminants for the medium
Thus it will give a designed chemical tracer. In a preferred embodiment, too low a temperature for urea in the storage container
Therefore, the heater may be turned on to maintain the temperature of the solution within the desired range.
U. In this mode of operation, auxiliary power or battery power to operate the heater
It is also preferred to monitor the availability of the sorbent. Determined that not enough power is available
Injectors and supply lines are drained to avoid freezing if
Will be. In this way, the engine control system alerts the operator.
Preferably without the use of reagents, for example with exhaust gas recirculation.
By reducing the ring, engine timing or lower power,
Engine operation with low NO _x Will control to maintain the level. In accordance with the preferred mode of operation, the quality of the urea solution is monitored,
If the test fails on more than one criterion, preferably the injector is stopped
Is done. In this way, the engine control system can alert the operator.
Preferably without the use of reagents, e.g. exhaust gas recirculation, air
Engine timing or mitigation to produce less power can reduce engine
Operation with low NO _x Will control to maintain the level. SCR system
System must be corrected again before full engine power is restored.
No. However, in other embodiments, return lines 33 and 33 ′ are not used.
Or is not the only means for maintaining the temperature. In this embodiment,
Heat exchange fluid such as air or engine coolant in heat exchange contact with the injector
Can be flushed. Optionally, in this embodiment, the temperature of the urea solution is
About 100 ° C. as long as the solution is maintained at a pressure above the saturated vapor pressure at that temperature
Can be higher. The SCR catalyst used reduces the concentration of exhausted nitric oxide in the presence of ammonia.
It can be. These include, for example, activated carbon, charcoal or coal,
Zeolite, vanadium oxide, tungsten oxide, titanium oxide, iron oxide, copper oxide
, Manganese oxide, chromium oxide, platinum, palladium, rhodium and iridium.
Noble metals such as platinum group metals or mixtures thereof. In the art
Other SCR catalyst materials that are common and well known to those skilled in the art can also be used.
Wear. These SCR catalyst materials typically use other known supports.
Where possible, supports such as metals, ceramics, zeolites or homogeneous monoliths
It is carried on. In particular, useful SCR catalysts are those representative prior art methods described below.
. NO _x Selective catalytic reduction for reducing is known and utilizes various catalytic reagents.
ing. For example, in European Patent Application WO 210,392, Eic
holtz and Weiler use activated wood as catalyst with the addition of ammonia.
We are studying the catalytic removal of nitric oxide using coal or activated coal. US Patent No. 4
No. 138,469 to Kato et al. And US Pat. No. 4,393,031 to Hen.
ke is a platinum group metal with the addition of ammonia to achieve the desired catalytic reduction.
Metals and / or such as titanium, copper, molybdenum, vanadium, tungsten
NO, using other metals or their oxides _x Discloses the catalytic reduction of Ma
Further, the V2O5 / WO3 / TiO2 catalyst was specified within the operating range of 220 to 280 ° C.
See also EP 487,886. Other catalysts based on platinum are
Will have a lower operating temperature, for example, less than about 180 ° C. Another catalytic reduction method is described in Knight's Canadian Patent No. 1,100,292.
This patent discloses a platinum group metal, gold, deposited on a refractory oxide.
And / or the use of silver catalysts. In U.S. Pat. No. 4,107,272,
Mori et al. Added vanadium, chromium, manganese,
NO, using oxysulfur, sulfate or sulfite compounds of iron, copper and nickel
We are studying the catalytic reduction of x. In a multi-phase catalyst system, Ginger in US Pat.
The oxide-containing exhaust gas is passed through a copper compound, such as copper sulfate, on a carrier in the presence of ammonia.
Catalysts containing vanadium and iron or tungsten and iron sulfates
It discloses exposing to a second catalyst comprising such a metal combination. The urea-introduced exhaust gas is preferably heated to a suitably high temperature, typically about 18
While maintaining the SCR contact temperature between 0 ° C. and about 650 ° C., for example, at least about 300 ° C.
Pass over the medium. In this manner, exhaust is performed for hydrolysis and gasification of the urea solution.
The active species present most effectively promotes the catalytic reduction of nitric oxide. Exhaustion
Qi will contain excess oxygen. The above SCR catalysts (these disclosures)
Is specifically incorporated by reference), by using the present invention with all of
Need for transportation, storage and handling of large amounts of ammonia or aqueous ammonia
Is reduced or eliminated. The above description is for the purpose of teaching those skilled in the art how to practice the present invention.
A detailed description of all obvious modifications and variations that will become apparent to those skilled in the art upon reading the description.
Is not intended. However, all such obvious modifications and variations have been
It is intended to be included within the scope of the present invention as defined by the appended claims.
It is. This claim is not claimed unless the context indicates otherwise.
In all sequences and series that are valid to meet the intended purpose for
Covering the indicated components and processes. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow diagram illustrating the basic components of one embodiment of the present invention.
Gram, where the chemical tracer responds to radiation within the specified wavelength range.
To test NOx reducing reagents (eg, aqueous urea) for the presence of
Sensors are provided. FIG. 2 is a logic diagram of one preferred mode of operation according to the present invention.
is there. FIG. 3 is a logic diagram of one preferred mode of operation according to the present invention.
is there. FIG. 4 is a logic diagram of one preferred mode of operation according to the present invention.
is there. FIG. 5 is a logic diagram of one preferred mode of operation according to the present invention.
is there. [Description of Signs] 10 Engine 12 Line 13 Injector 20 Exhaust pipe 21 Bend 30 Tank 31 Pressure line 31 'Pressure line 31 "Pressure line 33 Return line 33' Return line 34 SCR reactor 35 Rail pressure sensor 36 Pressure regulation Valve 37 Pump 38 Line 38 'Line 40 Controller 41 Engine sensor 42 Exhaust gas temperature sensor 43 Urea level sensor 44 Temperature sensor 45 Concentration sensor 46 Propeller 50 Heat exchanger 52 Reagent quality sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F01N 3/00 F02D 21/08 301Z 3G301 3/20 41/04 305A 4D002 3/24 360A 4D048 41/14 310Z F02D 21/08 301 45/00 301A 41/04 305 301G 360 310Z 41/14 310 G01N 21/78 C 45/00 301 31/00 H 31/10 310 B01D 53/36 101A G01N 21/78 53/34 129E 31/00 ZAB 31/10 (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ) , TM), AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, GH , GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZA , ZW (72) Inventor Lin, Meijin Linda 60540 Napaville, Illinois, United States Warey Road 8S 325 (72) Inventor Tarabalski, Theodor Jay 10509 Brewster Old Milltown Road, NY, USA (No address) F-term (reference) 2G042 AA10 BB07 CA01 CB01 DA07 DA08 2G054 AA01 CA06 EA03 3G084 AA01 AA04 BA01 BA09 BA13 BA15 BA20 BA24 BA33 DA10 DA27 DA28 EA11 EB01 EB22 FA10 FA13 FA18 FA26 FA27 FA33 FA38 3G091 AA02 AA04 AA06 AA11 AA12 AA17 AA18 AA28 AB05 BA14 BA21 BA31 CA13 CA17 CA27 CB03 CB08 DB10 EA01 GB03 EA01 GB03 GB09X GB10W GB10X GB17X HA36 HA37 HB03 HB05 3G092 AA01 AA02 AA06 AA09 AA13 AA17 AB02 AB03 AB20 AC05 AC10 BA01 BA04 BA06 BB01 BB06 DC01 DC09 DC10 DC14 DC15 DF02 EA07 EA11 EA28 EA29 HA17B01 HA05 FB05 HD04Z HE01Y HE01Z 3G301 HA01 HA02 HA04 HA06 HA13 HA15 HA26 JA25 JA33 JB07 JB08 JB09 JB10 LA01 LA03 LB01 LB11 MA01 MA11 MA18 NE11 NE12 NE15 PA11B PA11Z PA17B PA17Z PD01B PD01Z PD11B PD11Z PE01B PE01Z 4D002 AA12 AC10 BA06 BA12 BA13 CA01 CA07 CA13 DA07 DA56 DA57 GA02 GA03 GB03 GB05 GB08 GB20 4D048 AA06 AB02 AC03 DA02 DA09

Claims (1)

A presence of a guaranteed method of Claims 1] NO _x in the reduction system predefined quality of the NO _x reducing reagents, reagent solution for the presence of at least one fluorescent tracers Testing, generating a sensor signal indicative of the presence of a chemical tracer, comparing the sensor signal with a reference value, generating a control signal indicative of the result of the comparison, and urea solution in response to the control signal. Controlling the flow rate of the fluid. 2. Other parameters, such as reagent levels, can also be monitored by fluorimetry, physical and / or chemical means, and used to facilitate control, The method of claim 1. 3. The method of claim 1, wherein if the quality of the urea solution fails the test, the reagent injector is closed to prevent operation with a defective solution. 4. An engine or other control system may alert the operator, preferably mitigating without the use of reagents, for example, to provide exhaust gas recirculation, engine timing or less power. By doing
The engine operation is controlled to maintain the low NO _x level, The method of claim 3. 5. The system of claim 3, wherein the system preferably alerts an operator of a potential reduction in output, and the operator is required to replace the reagents with standard reagents before resuming normal operation. the method of. 7. A guaranteed method proper supply of the NO _x in the reduction system predefined quality of the NO _x reducing reagents, testing the reagent solution for the presence of at least one fluorescent tracers Generating a sensor signal indicating the concentration of the chemical tracer, comparing the sensor signal with a reference value, generating a control signal indicating the result of the comparison, and controlling the flow rate of the urea solution in response to the control signal A method that includes doing. 8. Other parameters, such as reagent levels, can also be monitored by fluorimetry, physical and / or chemical means, and can be used to facilitate control. The method of claim 7. 9. The method of claim 7, wherein if the quality of the urea solution fails the test, the reagent injector is closed to prevent operation with a defective solution. 10. An engine or other control system can alert the operator, preferably mitigating without the use of reagents, for example, to provide exhaust gas recirculation, engine timing or less power. it allows the engine operation is controlled to maintain the low NO _x level, the method of claim 9 wherein. 11. The system of claim 9, wherein the system preferably alerts the operator of the potential reduction in output, and the operator is required to replace the reagents with standard reagents before resuming normal operation. the method of. 12. A warranty apparatus of the presence of _the NO _x reduction system to the predefined quality in _the NO _x reduction reagent, _the NO _x reduction reagent quality sensor comprising a radiation source within a defined wavelength range, NO _An apparatus comprising supply means for supplying an _x- reducing reagent to an exhaust system including an SCR reactor and control means responsive to the quality sensor for controlling the supply of a NO _x reducing reagent. 13. A composition to ensure the presence of the NO _x in the reduction system predefined quality of the NO _x reducing reagents, reagent effective and defined wavelength range for _the NO _x reduction A composition comprising a chemical tracer that fluoresces when exposed to radiation within. 14. The composition of claim 13, further comprising a chemical tracer designed by a particular catalyst manufacturer to ensure that the composition does not contain contaminants for the particular catalyst used. Composition.