EP2142769A2 - A system and method for purifying exhaust gas for a diesel vehicle using fuel borne catalyst - Google Patents

A system and method for purifying exhaust gas for a diesel vehicle using fuel borne catalyst

Info

Publication number
EP2142769A2
EP2142769A2 EP08753335A EP08753335A EP2142769A2 EP 2142769 A2 EP2142769 A2 EP 2142769A2 EP 08753335 A EP08753335 A EP 08753335A EP 08753335 A EP08753335 A EP 08753335A EP 2142769 A2 EP2142769 A2 EP 2142769A2
Authority
EP
European Patent Office
Prior art keywords
fuel
catalyst
diesel
exhaust gas
control unit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08753335A
Other languages
German (de)
French (fr)
Other versions
EP2142769A4 (en
Inventor
Yunguen Cho
Sunghwan Kim
Hongseok Jung
Woojin Lee
Sangmin Lee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SK Innovation Co Ltd
Original Assignee
SK Energy Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SK Energy Co Ltd filed Critical SK Energy Co Ltd
Publication of EP2142769A2 publication Critical patent/EP2142769A2/en
Publication of EP2142769A4 publication Critical patent/EP2142769A4/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
    • F01N3/025—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust
    • F01N3/0253—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust adding fuel to exhaust gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
    • F01N3/029—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles by adding non-fuel substances to exhaust
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/05—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a particulate sensor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/06—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a temperature sensor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/01—Adding substances to exhaust gases the substance being catalytic material in liquid form
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/03—Adding substances to exhaust gases the substance being hydrocarbons, e.g. engine fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1473—Overflow or return means for the substances, e.g. conduits or valves for the return path
    • 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

Definitions

  • the present invention relates to a system and method for purifying exhaust gas for diesel vehicles using fuel borne catalyst (here-in-after, referred to as "FBC") which is applied to enhance the efficiency of purifying exhaust gas by maintaining optimum FBC concentration.
  • FBC fuel borne catalyst
  • a diesel vehicle has better durability of engine than that of a gasoline vehicle, with higher efficiency by 20-30%. Due to their excellent performances in terms of fuel efficiency and output of power, diesel vehicles have been applied to large vehicles such as trucks and buses. Furthermore, since diesel vehicles are advantageous in that they cause less global warming with small amount of CO 2 , CO, THC and evaporable hydrocarbons, diesel vehicles have been progressively applied to engines of small and medium sized vehicles. Thus, in developed countries, demand of small and medium sized diesel vehicles increases continuously. However, nitrogen oxides (NO x ) and particulate matters (PM) contained in exhaust of diesel vehicles in a substantial amount are recognized as principal cause of air pollution, constituting up to 40% of entire air pollution. Thus, environmental restrictions are strictly applied to manufacture of diesel vehicles.
  • NO x nitrogen oxides
  • PM particulate matters
  • post-treatment techniques include (1) oxidative catalysts for purifying unburned hydrocarbons in particulate matters (PM) , (2) diesel particulate filters (here-in-after, referred to as *DPF' ) to filter PM, and (3) DeNO x catalytic system to decompose or reduce nitrogen oxides (NO x ) under reductive atmosphere.
  • PM particulate matters
  • *DPF' diesel particulate filters
  • DeNO x catalytic system to decompose or reduce nitrogen oxides
  • particulate matters (PM) in exhaust gas contained in the exhaust gas flowing into a diesel particulate filter system is trapped by the diesel particulate filter system, to achieve removal of at least 90% of them.
  • PM particulate matters
  • the diesel particulate filter system may not only lose its capability of trapping, but also disturb driving of the engine owing to the back pressure thereon.
  • regeneration As a regeneration process, widely used is a process wherein diesel fuel is jet to the exhaust gas flowing into the diesel particulate filter system to cause spontaneous ignition to raise the temperature of the exhaust, and the hot exhaust gas is flowed into the diesel particulate filter system to burn off PM trapped in the diesel particulate filter system.
  • Several problems are indicated in such a system for purifying exhaust gas. First of all, the most serious problem is that the duration for properly regenerating a diesel particulate filter system and for raising the temperature of exhaust gas to enable the regeneration is too long.
  • temperature should be generally raised to 400 ° C or higher. It is well known that it takes about 10 minutes to raise the temperature of exhaust gas to said temperature in case of a vehicle with frequent stops, by using conventional system for purifying exhaust gas.
  • the present invention is to overcome the problems of conventional techniques as described above.
  • the object of the present invention is to provide a system and method for purifying exhaust gas for diesel vehicles using a fuel borne catalyst, which can easily raise the temperature of exhaust gas in a short time at the time of regeneration, by maintaining the proper concentration of the fuel borne catalyst constant in any driving situation.
  • the system for purifying exhaust gas for a diesel vehicle using fuel borne catalyst comprises an engine (100) ; a fuel tank (200) connected to said engine (100) , fuel supplying pipe (221) and fuel returning pipe (222) for supplying or returning diesel fuel; a diesel particulate filter system (300) connected to the exit (110) of the engine (100) for purifying exhaust gas and pollutants from the engine (100) to discharge them outward; an injection unit (400) equipped at the fore-end of the diesel particulate filter system (300) , which is connected to the fuel tank (200) , and comprises an injection pipe (431) , an injection pump (410) , an injector (420) and a circulation pipe (432) , in the order; and a control unit (500) which detects and determine the saturated state of said diesel particulate filter system (300) to control the operation of said injection unit (400) , additionally including a catalyst tank (610) to accommodate fuel borne catalyst (FBC) ;
  • the control unit (500) determines the required amount of the fuel borne catalyst to be injected through the catalyst injection unit (600) on the basis of the amount of residual diesel fuel inside the fuel tank (200) , measured by a level gauge (210) equipped for said fuel tank (200) . Further, the control unit (500) decides that it is in the state of fuel supplying when the change in the level (h) of diesel fuel measured by said level gauge (210) is positive (+) , while it decides that it is in the state of fuel supply completed when the change becomes 0 or negative (-) immediately after the change is positive (+) , and calculate the level difference
  • the other side of said catalyst injection pipe (630) according to the invention is connected to said circulation pipe (432) , or to said fuel returning pipe (222) .
  • a process for purifying exhaust gas for a diesel vehicle using fuel borne catalyst employing the system for purifying exhaust gas according to the present invention comprises the steps wherein a) the control unit detects the change in diesel fuel level in a fuel tank, measured by a level gauge; b) the control unit decides whether the change in fuel level becomes positive ( +) ; c) the control unit, upon deciding that the change in fuel level becomes positive (+) , decides the point as that of initiation of oil-supply and records the fuel level
  • control unit detects again the change in diesel fuel level in the fuel tank, measured by the level gauge; e) the control unit decides whether the change in fuel level becomes zero (0) or negative (-); f) the control unit, upon deciding that the change in fuel level becomes zero
  • control unit operates the catalyst injection unit to inject the required amount of injection (q) of the fuel borne catalyst, as calculated above.
  • the requirement for concentration of the fuel borne catalyst preferably is within the range of 170 ppm to 230 ppm.
  • concentration of fuel borne catalyst contained in diesel fuel is constantly- maintained, even in the situation that temperature of exhaust gas exited from the engine is not sufficiently high, such as under discrete and much changeable driving conditions or in a vehicle having low output of power like an automobile.
  • the temperature of exhaust gas can be easily raised in a short period during the regeneration of a diesel particulate filter system, so that regeneration of the diesel particulate filter system can be more efficiently accomplished.
  • the amount of diesel fuel to be consumed to raise the temperature of exhaust gas well enough for regeneration of the diesel particulate filter system can be significantly reduced. Accordingly, a significant effect of improvement in fuel efficiency of an entire vehicle is obtained.
  • the concentration of the fuel borne catalyst (of which the effects are described above) contained in diesel fuel can be automatically maintained constant at all time.
  • the problems of alteration of the above-mentioned effects over time or depending on fuel consumption or oiling can be completely eliminated. Therefore, steady effects as described above can be always obtained under any situation.
  • Fig. 1 is a schematic diagram of a system for purifying exhaust gas according to the present invention.
  • Fig. 2 is a flow diagram of a process for purifying exhaust gas according to the present invention.
  • Fig. 3 is a schematic description of individual variables.
  • circulation pipe 500 control unit
  • Fig. 1 shows schematic diagram of a system for purifying exhaust gas for diesel vehicles using fuel borne catalyst according to the present invention.
  • the system for purifying exhaust gas according to the present invention comprises an engine (100) driven by diesel fuel; a fuel tank (200) connected to said engine (100) , which supplies diesel fuel through a fuel supplying pipe (221) and returns residual diesel fuel in the engine through a fuel returning pipe (222) ; a diesel particulate filter system (300) connected to the exit
  • an injection unit (400) which comprises an injection pipe (431) of which one side is connected to said fuel tank (200) while other side is connected to an injector (420) , an injection pump (410) equipped on the injection pipe (431) to communicate diesel fuel, an injector (420) equipped at the fore-end of said diesel particulate filter system (300), which jets diesel fuel to induce spontaneous ignition when said diesel particulate filter system (300) is in a saturated state to raise the temperature of exhaust gas flowing into the diesel particulate filter system (300) to regenerate the unit (300) while is closed when the diesel particulate filter system (300) is not in a saturated state, and a circulation pipe
  • a control unit (500) which detects and determines the saturation of said diesel particulate filter system (300) to control the operation of said injection unit (400) , additionally including a catalyst tank (610) to accommodate fuel borne catalyst (FBC) ; a catalyst injection pipe (630) of which one side is connected to said catalyst tank (610) while the other side is connected to said system for purifying exhaust gas to provide communication of the fuel borne catalyst; a catalyst injector (620) equipped on the catalyst injection pipe (630) for injecting and mixing the fuel borne catalyst into and with the diesel fuel to constantly maintain the concentration of the fuel borne catalyst in the diesel fuel; and a catalyst injection unit (600) of which the operation is controlled by said control unit (500) .
  • the system according to the present invention as a whole is described in more detail here-in-below.
  • the engine (100) being connected to the fuel tank (200) via the fuel supplying pipe (221) , works by means of diesel fuel supply. It is common for an engine (100) using diesel fuel, that diesel fuel is not completely consumed but residual diesel fuel exists. For this case, a fuel returning pipe (222) is provided between the engine (100) and the fuel tank (200) to return the residual diesel fuel in engine (100) back to the fuel tank (200) . Exhaust gas containing exhaust gas generated from the engine (100) is purified when it passes through the diesel particulate filter system (300) connected to the exit
  • the diesel particulate filter system (300) employs a variety of post-treatment techniques as described above.
  • DPF diesel particulate filter
  • catalyst-coated filters are generally employed, but any devices to remove pollutants including particulate matters may be provided.
  • diesel fuel should be properly jet from the injector (420) .
  • various methods are employed to measure the degree of saturation in the diesel particulate filter system (300) .
  • a RPM sensor (120) in the engine (100) and a pressure sensor (321) and temperature sensors (322, 323) in the diesel particulate filter system (300) are provided, and the control unit (500) calculates the degree of saturation by using the variables such as revolution number (rpm) of the engine (100) , pressure and temperature, or pressure difference and temperature difference at the fore-end and rear-end of the diesel particulate filter system (300) , so that operation of injection unit (400) can be properly controlled thereby to adjust the amount of diesel fuel to be jet.
  • Those variables employed by the control unit (500) can be varied diversely depending on the design, and accordingly the location and number of the sensors to be provided.
  • the injection unit (400) generally consists of an injection pump (410) , an injector (420) , an injection pipe (431) and a circulation pipe (432) .
  • the injector When the diesel particulate filter system (300) become saturated or nearly saturated as described above, the injector
  • the system for purifying exhaust gas further comprises, in addition to the constitution of common purifying systems, a catalyst tank (610) accommodating fuel borne catalyst (FBC) , a catalyst injection pipe (630) which connects said catalyst tank (610) with said system for purifying exhaust, and a catalyst injection unit (600) comprising an injector (620) provided on the catalyst injection pipe (630) .
  • the catalyst injector (620) is controlled by the control unit (500), and properly injects fuel borne catalyst depending on the change of the amount of diesel fuel.
  • diesel particulate filter system (300) When fuel borne catalyst is mixed with diesel fuel in an appropriate concentration, temperature of exhaust gas can be very rapidly raised upon jetting diesel fuel into the exhaust gas flowing into the diesel particulate filter system (300) . Thus, the diesel particulate filter system (300) can be efficiently regenerated even in case of an urban bus with frequent stop/running repeats, or a diesel automobile having relatively low temperature of exhaust gas owing to low engine output of power.
  • concentration of fuel borne catalyst in diesel fuel accommodated in the fuel tank (200) is abruptly lowered after oiling, since the diesel fuel just oiled does not contain fuel borne catalyst. In case that diesel fuel was completely consumed and oiled, of course, the concentration of fuel borne catalyst approaches zero (0) .
  • the system of the present invention provides a catalyst tank (610) in a vehicle to properly inject fuel borne catalyst to diesel fuel, thereby maintaining the concentration of fuel borne catalyst in diesel fuel constant.
  • a catalyst tank (610) in a vehicle to properly inject fuel borne catalyst to diesel fuel, thereby maintaining the concentration of fuel borne catalyst in diesel fuel constant.
  • an appropriate amount of fuel borne catalyst is additionally injected to maintain the concentration of fuel borne catalyst, and thus the temperature of exhaust gas can be rapidly raised sufficiently to regenerate the diesel particulate filter system (300) , regardless of type or driving condition of a vehicle.
  • the amount of oiling of diesel fuel is directly related to the required amount of fuel borne catalyst to be injected.
  • the control unit (500) calculates the amount of diesel fuel by means of level gauge (210) provided in the fuel tank (200) , and calculates the required amount of fuel borne catalyst to be injected accordingly, to operate the catalyst injection unit (600) .
  • Fig. 1 (A) shows an example wherein the catalyst injection pipe (630) is connected to the circulation pipe (432) .
  • the catalyst injection pipe (630) is connected to the circulation pipe (432) .
  • the fuel borne catalyst can be effectively mixed with diesel fuel in the fuel tank (200) , so that the effect of temperature rise due to the fuel borne catalyst can be more readily achieved, as described above.
  • the catalyst injection pipe (630) can be connected to fuel returning pipe (222) as is shown in Fig. IB) .
  • the fuel borne catalyst is directly injected to the fuel tank (200) , it is not dispersed entirely to bring difficulties in mixing, thereby resulting in different concentrations of the fuel borne catalyst from one site to another site.
  • Connection of the catalyst injection pipe (630) at a position of active flow of diesel fuel, such as at the circulation pipe (432) or the fuel returning pipe (222) , as illustrated in Fig. 1 (A) or Fig. 1 (B) can overcome such a problem.
  • Fig. 2 illustrates one embodiment of the stage of injecting fuel borne catalyst according to the invention
  • Fig. 3 describes individual variables. Simply referring to the variables illustrated in Fig. 3, S is bottom area of the fuel tank; h is level of diesel fuel; h 0 is level of diesel fuel at the time of initiation of diesel fuel supply; h f is level of diesel fuel at the time of completion of diesel fuel supply; and q is flow rate of the fuel borne catalyst.
  • the control unit continuously detects the change in level of diesel fuel, measured by the level gauge provided in the fuel tank (SlOl) . During running, the amount of diesel fuel continually decreases, but rise of the level of diesel fuel
  • the control unit decides the point as that of initiation of oil supply, and records the level (h 0 ) at the point of initiation of oil supply (S103) . While the change in the level of diesel fuel is continually detected (S104) by the level gauge, when it is detected that the change becomes zero
  • the control unit decides the point as that of completion of oily supply and records the level (h f ) at the point of completion of oil supply (S106) .
  • the control unit calculates the difference ( ⁇ h) between the level of point of initiation of oil supply (h 0 ) and that of completion of oil supply (h f ) (S107) .
  • ⁇ h the difference between the level of point of initiation of oil supply (h 0 ) and that of completion of oil supply (h f ) (S107) .
  • the calculating equation used by the control unit can be simply expressed as follows.
  • the optimal concentration of the fuel borne catalyst preferably is in the range of 170 ppm to 230 ppm, and more preferably about 200 ppm.
  • c is determined to obtain the optimal concentration according to the user's design.
  • the control unit operates the catalyst injection unit to inject the required amount for injecting the fuel borne catalyst as calculated above to the fuel tank (S109) .
  • the concentration of fuel borne catalyst can be automatically maintained thereby, even if the fuel tank is filled with diesel fuel free of fuel borne catalyst by oiling.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Processes For Solid Components From Exhaust (AREA)

Abstract

The present invention relates to a system and method for purifying exhaust gas for diesel vehicles using fuel borne catalyst (here-in-after, referred to as 'FBC') which is applied to enhance the efficiency of purifying exhaust gas by maintaining optimum FBC concentration. The object of the present invention is to provide a system and method for purifying exhaust gas for diesel vehicles using a fuel borne catalyst, which can easily raise the temperature of exhaust gas in a short time at the time of regeneration, by maintaining the concentration of the fuel borne catalyst constant in any driving situation.

Description

[DESCRIPTION] [invention Title]
A System and Method for Purifying Exhaust Gas for a Diesel Vehicle using Fuel Borne Catalyst
[Technical Field]
The present invention relates to a system and method for purifying exhaust gas for diesel vehicles using fuel borne catalyst (here-in-after, referred to as "FBC") which is applied to enhance the efficiency of purifying exhaust gas by maintaining optimum FBC concentration.
A diesel vehicle has better durability of engine than that of a gasoline vehicle, with higher efficiency by 20-30%. Due to their excellent performances in terms of fuel efficiency and output of power, diesel vehicles have been applied to large vehicles such as trucks and buses. Furthermore, since diesel vehicles are advantageous in that they cause less global warming with small amount of CO2, CO, THC and evaporable hydrocarbons, diesel vehicles have been progressively applied to engines of small and medium sized vehicles. Thus, in developed countries, demand of small and medium sized diesel vehicles increases continuously. However, nitrogen oxides (NOx) and particulate matters (PM) contained in exhaust of diesel vehicles in a substantial amount are recognized as principal cause of air pollution, constituting up to 40% of entire air pollution. Thus, environmental restrictions are strictly applied to manufacture of diesel vehicles. Regarding the standards for emissions of nitrogen oxides and particulate matters, there are trade-offs between the countries, and individual countries control the degree of occurrences on the requirement for policy. With the oil prices we see today, diesel vehicles having higher efficiency than conventional gasoline vehicles have come into the spotlight. Accordingly, developed countries progressively build up more strict restrictions on the content of pollutant from the exhaust of diesel vehicles, in order to reduce the emissions of air pollutant generated, which is directly related to manufacture of diesel vehicles. Counter-techniques to meet the regulations for exhaust of diesel vehicles are classified into two groups: pre-treatment techniques for the purpose of reducing the source of generation of pollutant by means of improvements in fuel, combustion processes or structures of engines; and post- treatment techniques to purify exhaust gas generated, by means of equipment at the exit of exhaust. Though steady researches and developments are achieved in each field, the post- treatment techniques are considered to be more advantageous for practical use, up to the present, with more researches and developments proceeding. Those post-treatment techniques include (1) oxidative catalysts for purifying unburned hydrocarbons in particulate matters (PM) , (2) diesel particulate filters (here-in-after, referred to as *DPF' ) to filter PM, and (3) DeNOx catalytic system to decompose or reduce nitrogen oxides (NOx) under reductive atmosphere. Currently, post-treatment systems of hybride type, wherein various techniques described above are efficiently combined, such as DPF system equipped with a catalyst filter, are widely employed.
[Background Art]
In a conventional system for purifying exhaust gas, particulate matters (PM) in exhaust gas contained in the exhaust gas flowing into a diesel particulate filter system is trapped by the diesel particulate filter system, to achieve removal of at least 90% of them. When PM is saturated, the diesel particulate filter system may not only lose its capability of trapping, but also disturb driving of the engine owing to the back pressure thereon. Thus a process for removing PM saturated in the diesel particulate filter system
(referred to as regeneration) is required. As a regeneration process, widely used is a process wherein diesel fuel is jet to the exhaust gas flowing into the diesel particulate filter system to cause spontaneous ignition to raise the temperature of the exhaust, and the hot exhaust gas is flowed into the diesel particulate filter system to burn off PM trapped in the diesel particulate filter system. Several problems are indicated in such a system for purifying exhaust gas. First of all, the most serious problem is that the duration for properly regenerating a diesel particulate filter system and for raising the temperature of exhaust gas to enable the regeneration is too long. In case that a vehicle is driven continuously, for a practical instance, in a vehicle driven on a highway for a long period, even a small amount of diesel fuel jet can easily raise the temperature of exhaust, because the temperature of exhaust getting out of the engine is already hot. On the other hand, if a vehicle is discretely driven, for a practical instance, in a vehicle repeating driving/stop frequently such as urban buses, it is difficult to sufficiently raise the temperature of exhaust gas in a short time.
For regeneration, temperature should be generally raised to 400°C or higher. It is well known that it takes about 10 minutes to raise the temperature of exhaust gas to said temperature in case of a vehicle with frequent stops, by using conventional system for purifying exhaust gas.
In order to achieve rapid raise of temperature, conventional techniques of adding fuel borne catalyst (fuel additive) have been suggested. However, this could not be a fundamental solution because the concentration of fuel borne catalyst continually changes during the course of oiling with consumption of diesel fuel, and the effect of rapid raise of temperature due to the fuel borne catalyst abruptly decreases over time. Therefore, there has been steady demand to solve such problems by the persons having ordinary skill in the art.
[Disclosure]
[Technical Problem]
The present invention is to overcome the problems of conventional techniques as described above. The object of the present invention is to provide a system and method for purifying exhaust gas for diesel vehicles using a fuel borne catalyst, which can easily raise the temperature of exhaust gas in a short time at the time of regeneration, by maintaining the proper concentration of the fuel borne catalyst constant in any driving situation.
[Technical Solution]
In order to achieve the object as described above, the system for purifying exhaust gas for a diesel vehicle using fuel borne catalyst according to the present invention comprises an engine (100) ; a fuel tank (200) connected to said engine (100) , fuel supplying pipe (221) and fuel returning pipe (222) for supplying or returning diesel fuel; a diesel particulate filter system (300) connected to the exit (110) of the engine (100) for purifying exhaust gas and pollutants from the engine (100) to discharge them outward; an injection unit (400) equipped at the fore-end of the diesel particulate filter system (300) , which is connected to the fuel tank (200) , and comprises an injection pipe (431) , an injection pump (410) , an injector (420) and a circulation pipe (432) , in the order; and a control unit (500) which detects and determine the saturated state of said diesel particulate filter system (300) to control the operation of said injection unit (400) , additionally including a catalyst tank (610) to accommodate fuel borne catalyst (FBC) ; a catalyst injection pipe (630) , of which one side is connected to said catalyst tank (610) while the other side is connected to said system for purifying exhaust gas, to provide communication of the fuel borne catalyst; a catalyst injector (620) equipped on the catalyst injection pipe (630) for injecting and mixing the fuel borne catalyst into and with the diesel fuel to constantly maintain the concentration of the fuel borne catalyst in the diesel fuel; and a catalyst injection unit (600) of which the operation is controlled by said control unit (500) . The control unit (500) determines the required amount of the fuel borne catalyst to be injected through the catalyst injection unit (600) on the basis of the amount of residual diesel fuel inside the fuel tank (200) , measured by a level gauge (210) equipped for said fuel tank (200) . Further, the control unit (500) decides that it is in the state of fuel supplying when the change in the level (h) of diesel fuel measured by said level gauge (210) is positive (+) , while it decides that it is in the state of fuel supply completed when the change becomes 0 or negative (-) immediately after the change is positive (+) , and calculate the level difference
(Δh) between the initiation of the supply and completion of the supply, and it determines the required amount of the fuel borne catalyst to be injected through the catalyst injection unit (600) on the basis of said level difference (Δh) .
The other side of said catalyst injection pipe (630) according to the invention is connected to said circulation pipe (432) , or to said fuel returning pipe (222) .
A process for purifying exhaust gas for a diesel vehicle using fuel borne catalyst employing the system for purifying exhaust gas according to the present invention comprises the steps wherein a) the control unit detects the change in diesel fuel level in a fuel tank, measured by a level gauge; b) the control unit decides whether the change in fuel level becomes positive ( +) ; c) the control unit, upon deciding that the change in fuel level becomes positive (+) , decides the point as that of initiation of oil-supply and records the fuel level
(ho) at that point; d) the control unit detects again the change in diesel fuel level in the fuel tank, measured by the level gauge; e) the control unit decides whether the change in fuel level becomes zero (0) or negative (-); f) the control unit, upon deciding that the change in fuel level becomes zero
(0) or negative (-) in step e) , decides the point as that of completion of oil-supply and records the fuel level (hf) at that point; g) the control unit calculates the level difference (Δh=hf-h0) between the fuel level at the initiation of oil- supply (h0) and the fuel level at the completion of oil- supply (hf) ; h) the control unit calculates the required amount of injection (q) to meet the requirement for concentration of the fuel borne catalyst, on the basis of the level difference
(Δh) ; and i) the control unit operates the catalyst injection unit to inject the required amount of injection (q) of the fuel borne catalyst, as calculated above. The requirement for concentration of the fuel borne catalyst preferably is within the range of 170 ppm to 230 ppm.
[Advantageous Effects]
According to the present invention, concentration of fuel borne catalyst contained in diesel fuel is constantly- maintained, even in the situation that temperature of exhaust gas exited from the engine is not sufficiently high, such as under discrete and much changeable driving conditions or in a vehicle having low output of power like an automobile. Thus, the temperature of exhaust gas can be easily raised in a short period during the regeneration of a diesel particulate filter system, so that regeneration of the diesel particulate filter system can be more efficiently accomplished. In addition, the amount of diesel fuel to be consumed to raise the temperature of exhaust gas well enough for regeneration of the diesel particulate filter system can be significantly reduced. Accordingly, a significant effect of improvement in fuel efficiency of an entire vehicle is obtained.
According to the present invention, the concentration of the fuel borne catalyst (of which the effects are described above) contained in diesel fuel can be automatically maintained constant at all time. Thus the problems of alteration of the above-mentioned effects over time or depending on fuel consumption or oiling can be completely eliminated. Therefore, steady effects as described above can be always obtained under any situation. [Brief Description of Drawings ]
Fig. 1 is a schematic diagram of a system for purifying exhaust gas according to the present invention.
Fig. 2 is a flow diagram of a process for purifying exhaust gas according to the present invention.
Fig. 3 is a schematic description of individual variables.
<Description of symbols of significant parts of the drawings>
100: engine 110: exit
120: RPM sensor
200: fuel tank
210: level gauge
221: fuel supplying pipe 222: fuel returning pipe
300: diesel particulate filter system
310: exhaust pipe
321: pressure sensor
322, 323: temperature sensor 400: injection unit
410: injection pump
420: injector
431: injection pipe
432: circulation pipe 500: control unit
600: catalyst injection unit
610: catalyst tank
620: catalyst injector 630: catalyst injection pipe
[Best Mode]
Now the system for purifying exhaust gas for diesel vehicles using fuel borne catalyst according to the present invention, having the constitution as mentioned above is described in more detail by referring to the appended drawings.
Fig. 1 shows schematic diagram of a system for purifying exhaust gas for diesel vehicles using fuel borne catalyst according to the present invention. The system for purifying exhaust gas according to the present invention comprises an engine (100) driven by diesel fuel; a fuel tank (200) connected to said engine (100) , which supplies diesel fuel through a fuel supplying pipe (221) and returns residual diesel fuel in the engine through a fuel returning pipe (222) ; a diesel particulate filter system (300) connected to the exit
(110) of the engine (100) for purifying exhaust gas and pollutants from the engine (100) to discharge them outward; an injection unit (400) which comprises an injection pipe (431) of which one side is connected to said fuel tank (200) while other side is connected to an injector (420) , an injection pump (410) equipped on the injection pipe (431) to communicate diesel fuel, an injector (420) equipped at the fore-end of said diesel particulate filter system (300), which jets diesel fuel to induce spontaneous ignition when said diesel particulate filter system (300) is in a saturated state to raise the temperature of exhaust gas flowing into the diesel particulate filter system (300) to regenerate the unit (300) while is closed when the diesel particulate filter system (300) is not in a saturated state, and a circulation pipe
(432) of which one side is connected to said injector (420) while the other side is connected to said fuel tank (200) and returns the diesel fuel flowing in through the injection pipe
(431) back to said fuel tank (200) when the injector (420) is closed; and a control unit (500) which detects and determines the saturation of said diesel particulate filter system (300) to control the operation of said injection unit (400) , additionally including a catalyst tank (610) to accommodate fuel borne catalyst (FBC) ; a catalyst injection pipe (630) of which one side is connected to said catalyst tank (610) while the other side is connected to said system for purifying exhaust gas to provide communication of the fuel borne catalyst; a catalyst injector (620) equipped on the catalyst injection pipe (630) for injecting and mixing the fuel borne catalyst into and with the diesel fuel to constantly maintain the concentration of the fuel borne catalyst in the diesel fuel; and a catalyst injection unit (600) of which the operation is controlled by said control unit (500) . The system according to the present invention as a whole is described in more detail here-in-below.
The engine (100) , being connected to the fuel tank (200) via the fuel supplying pipe (221) , works by means of diesel fuel supply. It is common for an engine (100) using diesel fuel, that diesel fuel is not completely consumed but residual diesel fuel exists. For this case, a fuel returning pipe (222) is provided between the engine (100) and the fuel tank (200) to return the residual diesel fuel in engine (100) back to the fuel tank (200) . Exhaust gas containing exhaust gas generated from the engine (100) is purified when it passes through the diesel particulate filter system (300) connected to the exit
(110) , and discharged through the exhaust pipe (310) . The diesel particulate filter system (300) employs a variety of post-treatment techniques as described above. DPF (diesel particulate filter) systems provided with catalyst-coated filters are generally employed, but any devices to remove pollutants including particulate matters may be provided.
When particulate matters (PM) become saturated or nearly saturated in the diesel particulate filter system (300) , the capability of trapping PM may decrease, and a serious problem may occur in the driving of engine owing to the back pressure. Thus a measure to avoid such a situation is required. In case of using diesel fuel, if an injector (420) connected to the fuel tank (200) is provided at the entrance of the diesel particulate filter system (300) and diesel fuel is jet to the exhaust gas to cause spontaneous ignition, thereby forcibly raising the temperature of exhaust gas flowing into said diesel particulate filter system (300) , PM saturated inside the diesel particulate filter system (300) can be removed by combustion by means of hot exhaust gas thus formed.
In order to regenerate the diesel particulate filter system (300) as described above, diesel fuel should be properly jet from the injector (420) . Thus, various methods are employed to measure the degree of saturation in the diesel particulate filter system (300) . Currently, a RPM sensor (120) in the engine (100) , and a pressure sensor (321) and temperature sensors (322, 323) in the diesel particulate filter system (300) are provided, and the control unit (500) calculates the degree of saturation by using the variables such as revolution number (rpm) of the engine (100) , pressure and temperature, or pressure difference and temperature difference at the fore-end and rear-end of the diesel particulate filter system (300) , so that operation of injection unit (400) can be properly controlled thereby to adjust the amount of diesel fuel to be jet. Those variables employed by the control unit (500) can be varied diversely depending on the design, and accordingly the location and number of the sensors to be provided.
As illustrated in Fig. 1, the injection unit (400) generally consists of an injection pump (410) , an injector (420) , an injection pipe (431) and a circulation pipe (432) . When the diesel particulate filter system (300) become saturated or nearly saturated as described above, the injector
(420) jets diesel fuel by the injection pump (410) via the injection pipe (431) . On the other hand, when the diesel particulate filter system (300) is not in a saturated state and does not need fuel jet, the injector (430) is closed and diesel fuel which was supplied through the injection pipe (431) returns back to the fuel tank (200) via the circulation pipe (432) .
The system for purifying exhaust gas according to the present invention further comprises, in addition to the constitution of common purifying systems, a catalyst tank (610) accommodating fuel borne catalyst (FBC) , a catalyst injection pipe (630) which connects said catalyst tank (610) with said system for purifying exhaust, and a catalyst injection unit (600) comprising an injector (620) provided on the catalyst injection pipe (630) . In order to maintain the concentration of fuel borne catalyst contained in diesel fuel constant, the catalyst injector (620) is controlled by the control unit (500), and properly injects fuel borne catalyst depending on the change of the amount of diesel fuel.
When fuel borne catalyst is mixed with diesel fuel in an appropriate concentration, temperature of exhaust gas can be very rapidly raised upon jetting diesel fuel into the exhaust gas flowing into the diesel particulate filter system (300) . Thus, the diesel particulate filter system (300) can be efficiently regenerated even in case of an urban bus with frequent stop/running repeats, or a diesel automobile having relatively low temperature of exhaust gas owing to low engine output of power. However, when diesel fuel is consumed with driving, and the vehicle is newly oiled, the concentration of fuel borne catalyst in diesel fuel accommodated in the fuel tank (200) is abruptly lowered after oiling, since the diesel fuel just oiled does not contain fuel borne catalyst. In case that diesel fuel was completely consumed and oiled, of course, the concentration of fuel borne catalyst approaches zero (0) . In such a case, the effect of raising the temperature of exhaust gas is abruptly lowered. Accordingly, the ability of regeneration of diesel particulate filter system (300) becomes poorer with repeated oiling. In order to overcome such a problem, the system of the present invention provides a catalyst tank (610) in a vehicle to properly inject fuel borne catalyst to diesel fuel, thereby maintaining the concentration of fuel borne catalyst in diesel fuel constant. In other word, if diesel fuel is consumed and newly oiled, an appropriate amount of fuel borne catalyst is additionally injected to maintain the concentration of fuel borne catalyst, and thus the temperature of exhaust gas can be rapidly raised sufficiently to regenerate the diesel particulate filter system (300) , regardless of type or driving condition of a vehicle.
The amount of oiling of diesel fuel is directly related to the required amount of fuel borne catalyst to be injected. Thus, the control unit (500) calculates the amount of diesel fuel by means of level gauge (210) provided in the fuel tank (200) , and calculates the required amount of fuel borne catalyst to be injected accordingly, to operate the catalyst injection unit (600) .
Fig. 1 (A) shows an example wherein the catalyst injection pipe (630) is connected to the circulation pipe (432) . When fuel borne catalyst is injected to the circulation pipe (432), the fuel borne catalyst can be effectively mixed with diesel fuel in the fuel tank (200) , so that the effect of temperature rise due to the fuel borne catalyst can be more readily achieved, as described above.
Alternatively, the catalyst injection pipe (630) can be connected to fuel returning pipe (222) as is shown in Fig. IB) .
If the fuel borne catalyst is directly injected to the fuel tank (200) , it is not dispersed entirely to bring difficulties in mixing, thereby resulting in different concentrations of the fuel borne catalyst from one site to another site. Connection of the catalyst injection pipe (630) at a position of active flow of diesel fuel, such as at the circulation pipe (432) or the fuel returning pipe (222) , as illustrated in Fig. 1 (A) or Fig. 1 (B) , can overcome such a problem.
Fig. 2 illustrates one embodiment of the stage of injecting fuel borne catalyst according to the invention, while Fig. 3 describes individual variables. Simply referring to the variables illustrated in Fig. 3, S is bottom area of the fuel tank; h is level of diesel fuel; h0 is level of diesel fuel at the time of initiation of diesel fuel supply; hf is level of diesel fuel at the time of completion of diesel fuel supply; and q is flow rate of the fuel borne catalyst.
The stage of injecting the fuel borne catalyst according to the invention is described by referring to Fig. 2. First, the control unit continuously detects the change in level of diesel fuel, measured by the level gauge provided in the fuel tank (SlOl) . During running, the amount of diesel fuel continually decreases, but rise of the level of diesel fuel
(where the change in level of diesel fuel becomes positive
( +) ) occurs only at oiling. Thus, when it is detected by the control unit that the change of level becomes positive (+)
(S102), the control unit decides the point as that of initiation of oil supply, and records the level (h0) at the point of initiation of oil supply (S103) . While the change in the level of diesel fuel is continually detected (S104) by the level gauge, when it is detected that the change becomes zero
(0) or negative (-) (S105) , the control unit decides the point as that of completion of oily supply and records the level (hf) at the point of completion of oil supply (S106) . The control unit calculates the difference (Δh) between the level of point of initiation of oil supply (h0) and that of completion of oil supply (hf) (S107) . By using the difference of level (Δh) , calculated is the amount of diesel fuel newly supplied, and the control unit then calculates, on the basis of the amount, the required amount of fuel borne catalyst to be additionally injected to maintain the concentration of the fuel borne catalyst (S108) . The calculating equation used by the control unit can be simply expressed as follows. Each variable in the equation is identical to that of Fig. 3, and c is a proportional factor. The optimal concentration of the fuel borne catalyst preferably is in the range of 170 ppm to 230 ppm, and more preferably about 200 ppm. Thus, c is determined to obtain the optimal concentration according to the user's design. q = cΔh
(Δh = hf - ho)
The control unit operates the catalyst injection unit to inject the required amount for injecting the fuel borne catalyst as calculated above to the fuel tank (S109) . Thus, the concentration of fuel borne catalyst can be automatically maintained thereby, even if the fuel tank is filled with diesel fuel free of fuel borne catalyst by oiling.
The present invention is not restricted to the examples described above, but can be extensively applied in a variety of industrial fields. It is obvious that any person having ordinary skill in the art to which the present invention belongs can modify and practise the invention without departing from the gist of the invention claimed by the appended claims.

Claims

[CLAIMS]
[Claim l]
A system for purifying exhaust gas for a diesel vehicle using fuel borne catalyst, comprising an engine (100) ; a fuel tank (200) connected to said engine (100) , fuel supplying pipe
(221) and fuel returning pipe (222) for supplying or returning diesel fuel; a diesel particulate filter system (300) connected to the exit (110) of the engine (100) for purifying exhaust gas and pollutants from the engine (100) to discharge them outward; an injection unit (400) equipped at the fore-end of the diesel particulate filter system (300) , which is connected to the fuel tank (200), and comprises an injection pipe (431) , an injection pump (410) , an injector (420) and a circulation pipe (432) , in the order; and a control unit (500) which detects and determine the saturated state of said diesel particulate filter system (300) to control the operation of said injection unit (400) , which further comprises a catalyst tank (610) to accommodate fuel borne catalyst (FBC) ; a catalyst injection pipe (630) , of which one side is connected to said catalyst tank (610) while the other side is connected to said system for purifying exhaust gas, to provide communication of the fuel borne catalyst; a catalyst injector (620) equipped on the catalyst injection pipe (630) for injecting and mixing the fuel borne catalyst into and with the diesel fuel to constantly maintain the concentration of the fuel borne catalyst in the diesel fuel; and a catalyst injection unit (600) of which the operation is controlled by said control unit (500) .
[Claim 2]
A system for purifying exhaust gas for a diesel vehicle using fuel borne catalyst according to claim 1, wherein the control unit (500) determines the required amount of the fuel borne catalyst to be injected through the catalyst injection unit (600) on the basis of the amount of residual diesel fuel inside the fuel tank (200) , measured by a level gauge (210) equipped for said fuel tank (200) .
[Claim 3]
A system for purifying exhaust gas for a diesel vehicle using fuel borne catalyst according to claim 2, wherein the control unit (500) decides that it is in the state of fuel supplying when the change in the level (h) of diesel fuel measured by said level gauge (210) is positive (+) , while it decides that it is in the state of fuel supply completed when the change becomes 0 or negative (-) immediately after the change is positive ( +) , and calculate the level difference (Δh) between the initiation of the supply and completion of the supply, and it determines the required amount of the fuel borne catalyst to be injected through the catalyst injection unit (600) on the basis of said level difference (Δh) .
[Claim 4]
A system for purifying exhaust gas for a diesel vehicle using fuel borne catalyst according to any one of claims 1 to 3, wherein the other side of said catalyst injection pipe (630) is connected to said circulation pipe (432) .
[Claim 5]
A system for purifying exhaust gas for a diesel vehicle using fuel borne catalyst according to any one of claims 1 to 3, wherein the other side of said catalyst injection pipe (630) is connected to said fuel returning pipe (222) .
[Claim 6] A process for purifying exhaust gas for a diesel vehicle using fuel borne catalyst, employing the system for purifying exhaust gas according to claim 1, which comprises the steps wherein a) the control unit detects the change in diesel fuel level in a fuel tank, measured by a level gauge; b) the control unit decides whether the change in fuel level becomes positive ( +) ; c) the control unit, upon deciding that the change in fuel level becomes positive (+) , decides the point as that of initiation of oil-supply and records the fuel level (h0) at that point; d) the control unit detects again the change in diesel fuel level in the fuel tank, measured by the level gauge; e) the control unit decides whether the change in fuel level becomes zero (0) or negative (-); f) the control unit, upon deciding that the change in fuel level becomes zero (0) or negative (-) in step e) , decides the point as that of completion of oil-supply and records the fuel level (hf) at that point; g) the control unit calculates the level difference (Δh=hf-h0) between the fuel level at the initiation of oil- supply (h0) and the fuel level at the completion of oil-supply (hf) ; h) the control unit calculates the required amount of injection (q) to meet the requirement for concentration of the fuel borne catalyst, on the basis of the level difference
(Δh) ; i) the control unit operates the catalyst injection unit to inject the required amount of injection (q) of the fuel borne catalyst, as calculated above.
[Claim 7] A process for purifying exhaust gas for a diesel vehicle using fuel borne catalyst according to claim 6, wherein the requirement for concentration of the fuel borne catalyst is within the range of 170 ppm to 230 ppm.
EP08753335.2A 2007-05-10 2008-05-06 A system and method for purifying exhaust gas for a diesel vehicle using fuel borne catalyst Withdrawn EP2142769A4 (en)

Applications Claiming Priority (2)

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KR1020070045466A KR101290525B1 (en) 2007-05-10 2007-05-10 A System and Method for Purifying Exhaust Gas for a Diesel Vehicle using Fuel Borne Catalyst
PCT/KR2008/002538 WO2008140204A2 (en) 2007-05-10 2008-05-06 A system and method for purifying exhaust gas for a diesel vehicle using fuel borne catalyst

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EP2142769A4 EP2142769A4 (en) 2014-03-05

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CN101680334A (en) 2010-03-24
KR20080099650A (en) 2008-11-13
CN101680334B (en) 2012-11-07
KR101290525B1 (en) 2013-07-30
EP2142769A4 (en) 2014-03-05
WO2008140204A3 (en) 2008-12-31
WO2008140204A2 (en) 2008-11-20
JP2010526959A (en) 2010-08-05

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