EP1895144B1 - Diagnostic de fuite de gaz - Google Patents

Diagnostic de fuite de gaz Download PDF

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Publication number
EP1895144B1
EP1895144B1 EP20060120073 EP06120073A EP1895144B1 EP 1895144 B1 EP1895144 B1 EP 1895144B1 EP 20060120073 EP20060120073 EP 20060120073 EP 06120073 A EP06120073 A EP 06120073A EP 1895144 B1 EP1895144 B1 EP 1895144B1
Authority
EP
European Patent Office
Prior art keywords
pump
gas
performance
tank assembly
leakage
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.)
Not-in-force
Application number
EP20060120073
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German (de)
English (en)
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EP1895144A1 (fr
Inventor
Olof Lindgarde
Krister Johansson
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.)
Ford Global Technologies LLC
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Ford Global Technologies LLC
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Publication date
Application filed by Ford Global Technologies LLC filed Critical Ford Global Technologies LLC
Priority to DE200660013630 priority Critical patent/DE602006013630D1/de
Priority to EP08105249.0A priority patent/EP1998037B1/fr
Priority to EP20060120073 priority patent/EP1895144B1/fr
Publication of EP1895144A1 publication Critical patent/EP1895144A1/fr
Application granted granted Critical
Publication of EP1895144B1 publication Critical patent/EP1895144B1/fr
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Classifications

    • 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
    • F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir
    • F02M25/0809—Judging failure of purge control system
    • 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
    • F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir
    • F02M25/0809—Judging failure of purge control system
    • F02M25/0818—Judging failure of purge control system having means for pressurising the evaporative emission space

Definitions

  • the present relation relates to a method for estimating a leakage area in a vehicle tank assembly according to the preamble of claim 1 and to a method of estimating a performance from a plurality of pump assemblies and/or at least one pump assembly at different time periods according to the preamble of claim 25.
  • Vehicles for example cars, are generally equipped with at least one vehicle tank assembly comprising a tank adapted for storing a fluid, for example fuel for powering the vehicle. Furthermore, the vehicle tank assembly generally comprises a connector by which a content of the tank may be supplied to a receiving part of the vehicle. If the tank is adapted for storing fuel, an internal combustion engine of the vehicle is generally supplied with the fuel through the aforementioned connector.
  • the fluid stored in the tank may be volatile, hence a leak in the vehicle tank assembly at a location above the actual fluid level may result in that evaporated fluid may exit the tank assembly and enter the surrounding atmosphere. If the evaporated fluid comprises noxious particles, such as hydrocarbons, the evaporated fluid may be harmful both to the environment in the vicinity of the vehicle tank assembly, as well as to the global environment.
  • the leakage test can be performed with equipment provided with the vehicle itself, i.e. a leakage test can be performed without having to visit a service facility or similar.
  • Prior art teaches the use of several leakage testing methods, but they generally require a large amount of measurement test results and generally only determine if a leakage is present or not, based on comparing the test results with empirically obtained reference values.
  • the initial gas volume of the vehicle tank assembly being the total volume of the tank assembly minus the volume of the liquid stored within the tank assembly, has to be known prior to performing a leakage test. Determining the initial gas volume requires additional metering devices which may be required to provide results with an accuracy which is similar to the accuracy of the rest of the leakage test equipment. As such, a regular tank gauge may not be sufficiently accurate and thus there may be a need for introducing additional expensive metering devices in the vehicle tank assembly.
  • US 2005/0044937 discloses fuel vapor leakage check module has a canister port which is provided so that the port can be opened to the air and is connected to the interior of a fuel tank through a canister for absorbing fuel vapor produced in the fuel tank.
  • a pump depressurizes or pressurizes the interior of the fuel tank through the canister port.
  • a connecting passage which is coaxially provided in the canister port, is connected to the canister port. The connecting passage is depressurized or pressurized by the pump.
  • a standard orifice is coaxially provided in the connecting passage and reduces the passage area of the connecting passage.
  • US 6,082,189 discloses that a tank venting system is evacuated by the negative pressure prevailing in the intake pipe of the internal combustion engine.
  • a regression calculation based on a physical model which simulates the pressure variation in the event of a leak in the tank venting system, on the basis of a gas mass flow flowing through an opening, supplies a parameter which describes the curve variation of the pressure during the test for gassing out fuel and during the diagnosis.
  • the parameter contains the information about the leak area and takes into account external influences that interfere with the signal evaluation.
  • US 2004/0226347 discloses a fuel system with a pressure-sensitive monitor accumulates multiple pressure-related sample points and estimates the general trend of pressure change in a fuel system over time, thereby detecting the presence or absence of a fuel vapor leak in the fuel system.
  • EP 1 510 804 discloses a method for diagnosing a leakage in a vessel, which vessel is provided with an electric pump for pressurising the vessel, a sensor for measuring a drive current used for driving the pump and generating a current signal, an electronic control unit for sampling, storing and analysing said drive current signal.
  • US 2002/0011094 discloses a method and sensor or sensor subsystem permit improved evaporative leak detection in an automotive fuel system.
  • the sensor or sensor subsystem computes temperature-compensated pressure values, thereby eliminating or reducing false positive or other adverse results triggered by temperature changes in the fuel tank.
  • the temperature-compensated pressure measurement is then available for drawing an inference regarding the existence of a leak with reduced or eliminated false detection arising as a result of temperature fluctuations.
  • a first object of the invention is to provide a leakage testing method, wherein the area of a leakage is estimated.
  • a second object of the invention is to provide a leakage testing method, in which the initial gas volume of the vehicle tank assembly does not need to be known.
  • a third object of the invention is to provide a leakage testing method, which may be performed under a plurality of different testing conditions, for example at different temperatures and/or different degrees of fullness of liquid in the tank assembly.
  • a fourth object of the invention is to provide a leakage testing method, in which additional disturbances of the measurements, for instance induced by additional components of the tank assembly, such as a canister, may be easily accounted for.
  • At least one of the aforementioned objects is achieved by a method for estimating a leakage area in a vehicle tank assembly as set out in appended claim 1.
  • the invention relates to a method for estimating a leakage area in a vehicle tank assembly.
  • the tank assembly comprises a tank, a gas pump in fluid communication with the rest of the tank assembly and means for determining a pressure in the tank assembly and a gas mass flow through the gas pump.
  • the method comprises the step of varying the pressure in the tank assembly by applying the gas mass flow through the gas pump during an area estimation time period.
  • the method further comprises the steps of:
  • a leakage area may be unambiguously estimated. Furthermore, since the estimation is performed on the basis of an instantaneous gas flow relation for a plurality of time instants, a reliable estimate of the leakage area may be obtained.
  • a further embodiment of the inventive method further comprises the feature that the estimation of the leakage area is executed by arranging the instantaneous gas mass flow relations of the gas in an equations system and determining the leakage area by utilizing a least-squares method.
  • a least-squares method is an efficient method of estimating a parameter in an over-determined equations system. Furthermore, the average square error of the area estimate is minimized when utilizing the least-squares method.
  • Another embodiment of the inventive method further comprises the aspect that the arrangement of the gas mass flow relation of the gas is solved by utilizing a recursive least-squares method.
  • Utilizing a recursive least-squares method results in a leakage area estimation method which requires a minimum of stored data. As such, if the method is implemented on e.g. an electronic control unit, a need of memory capacity of the control unit is kept to a minimum.
  • Another embodiment of the inventive method further includes each instantaneous gas mass flow relation being an equality based on an ideal gas law.
  • the ideal gas law is in many applications a reasonably good approximation of the condition of the gas within the tank assembly, while still being sufficiently simple in order to be used for implementing a relatively simple leakage area estimation method.
  • a first side of the equality comprises a first entity minus a second entity, wherein
  • the leakage flow is determined by a leakage measure, wherein the leakage measure is a product of: the unknown leakage area and the value of a leakage function, wherein the leakage function is a function of at least the pressure in the tank assembly.
  • Another embodiment of the inventive method further includes the leakage function further being a function of the pressure of a medium surrounding the tank assembly and/or the temperature of the gas in the tank assembly and/or a temperature of the surrounding medium. Incorporating any of the above mentioned entities in the estimate of the leakage function may result in an enhanced estimate of the leakage area.
  • a second side of the equality comprises a third entity, wherein
  • a further embodiment of the inventive method further includes the second side of the equality comprising a fourth entity, subtracted from said third entity, wherein
  • the aforementioned change in volume is modelled as a function of at least the gas temperature and pressure in the tank assembly.
  • an estimate of the change in volume may be obtained without any need of directly measuring changes in dimensions of the tank assembly.
  • Yet another embodiment of the inventive method comprises the feature that the tank assembly comprises a canister in fluid communication with the tank, where a fifth entity is added to the first side of the equality, wherein
  • a sixth entity is added to the first side of the equality, wherein
  • a further embodiment of the inventive method further requires that the gas temperature in the tank assembly is assumed to be constant throughout the area estimation time period. This assumption simplifies the analysis in the leakage area estimation method and also significantly reduces the need of temperature measurements in the tank assembly.
  • the gas pump is supplied with electrical power, wherein each of the change in pressure and the gas mass flow through the gas pump, respectively, is estimated by a performance function of an applied pump electrical current, each performance function having a set of performance coefficients.
  • a further embodiment of the inventive method further comprises the feature that each of the performance functions is estimated by an affine performance function.
  • An affine performance function comprises few parameters and fitting data to an affine function may be performed by utilizing one of a plurality conventional techniques, such as a linear regression method.
  • the performance coefficients of each of the affine performance functions are dependent on at least a voltage supplied to the gas pump. Since the voltage may vary between different tank assemblies, for example between tank assemblies in different vehicles, and the electrical power supplied to the gas pump is proportional to the voltage, the estimate of the performance of a gas pump is enhanced if the voltage is taken into account.
  • a further embodiment of the inventive method stipulates that the tank assembly comprises a reference opening and a gas valve for controlling the gas mass flow, the valve being operable to guide the gas mass flow at least either through the reference opening or to the tank assembly, wherein the performance coefficients of the performance functions are established by a coefficient estimation method comprising the step of operating the valve in order to guide the flow through the reference opening and determining a corresponding pump reference electrical current and determining the performance coefficients of each of the performance functions depending on the corresponding pump reference electrical current.
  • Another embodiment of the inventive method includes the performance coefficients of the performance functions being established by a coefficient estimation method comprising the step of operating the valve in order to guide the flow to the tank assembly and determining an initial corresponding pump minimum electrical current, and determining the performance coefficients of each of the performance functions dependent on the corresponding pump minimum electrical current. Utilizing the aforementioned method will further enhance the opinion of the condition of the specific gas pump and the information concerning the pump minimum electrical current may thus preferably be used when determining the performance coefficient by quantitatively using the acquired knowledge regarding the pump minimum electrical current.
  • the invention further relates to a method for testing leakage in a vehicle tank assembly, wherein the leakage testing method comprises the step of estimating a leakage area according to any of the aforementioned inventive methods.
  • the leakage testing method of the invention instead of comparing a measured state of the gas within the tank assembly to empirically obtained reference states and further, from the result of the comparison determining whether a leakage with at least a predetermined area is present or not, the leakage testing method of the invention instead first determines an estimate of the leakage area.
  • Another embodiment of the inventive leakage testing method further comprises the step of comparing the estimated leakage area to a predetermined threshold value.
  • a predetermined threshold value For example the guidelines for a maximum allowable leakage area in a tank assembly change due to e.g. legal requirements, the method of the invention has only to be updated by introducing a new threshold value instead of having to generate a new set of empirically obtained reference data.
  • a further embodiment of the inventive leakage testing method further comprises the step of transmitting a warning signal if the estimated leakage area exceeds the predetermined threshold value and/or the step of transmitting an acceptance signal if the estimated leakage area is lower than the predetermined threshold value.
  • the invention further relates to a computer program product, comprising a computer program containing computer program code executable in a computer or a processor to implement at least one of the steps of any of the aforementioned methods.
  • the product is stored on a computer-readable medium or a carrier wave.
  • the invention further relates to an electronic control unit comprising the aforementioned computer program product.
  • the electronic control unit is further arranged to execute a previously disclosed leakage area estimation method and/or a leakage testing method
  • the invention further relates to a vehicle, comprising the aforementioned electronic control.
  • a fifth object of the invention is to provide a method for estimating a performance of a pump assembly as a function of the applied pump electrical current, wherein differences between different pumps of the same model and/or aging of a pump are accounted for.
  • This fifth object is achieved by a performance estimating function defined in the attached claim.
  • the invention further relates to a method of estimating a performance from a plurality of pump assemblies and/or at least one pump assembly at different time periods.
  • Each pump assembly comprises a gas pump, wherein the performance is indicative of at least a gas mass flow through the gas pump.
  • each pump assembly comprises a reference opening and a gas valve for controlling the gas mass flow, the valve being operable to guide the gas mass flow at least either through the reference opening or through an outlet opening.
  • the gas pump is supplied with electrical power.
  • the method comprises the steps of:
  • a further embodiment of the inventive performance testing method further comprises the step of estimating each of the performance functions by an affine performance function.
  • Another embodiment of the inventive performance testing method further comprises the step of estimating the coefficients to each of the affine performance functions by utilizing a least-squares method.
  • a further embodiment of the inventive performance testing method further comprises the step of estimating the coefficients to each of the affine performance functions by utilizing a recursive least-squares method.
  • the pump assembly forms a part of a vehicle tank assembly, the pump assembly being in fluid communication with the rest of the tank assembly and the pump assembly performance comprises a resulting change in pressure in the tank assembly.
  • an output comprising the gas mass flow through the pump, from a pump assembly may be estimated.
  • a method of estimating the output, based on the performance coefficient function comprises the steps of:
  • the output estimated may preferably comprise a change in pressure in a tank assembly if such a tank assembly is in fluid communication with the pump assembly.
  • Fig. 1 illustrates a vehicle tank assembly 10 on which at least the leakage area estimation method of the invention may preferably be applied.
  • the tank assembly 10 comprises a tank 12 which is adapted to store a liquid 14, such as fuel. Due to e.g. improper handling of the vehicle tank assembly, the tank assembly 10, above a liquid level 16, may be provided with a leakage opening 18 having a leakage area A leak . It has been observed that one frequent location of the leakage opening 18 is in the vicinity of a filler cap 22. Thus, evaporated liquid from the stored liquid 14 may exit the tank assembly 10 and enter the surrounding atmosphere.
  • the tank assembly 10 optionally comprises a canister 24 in fluid communication with the tank 12. Furthermore, the tank assembly preferably comprises a gas pump 26. However, in some implementations of the tank assembly 10 on which the method of the invention is preferably applied, the gas pump 26 may preferably be replaced by other gas pressurising means, for example a gas tank having an initial gas pressure which is different than the initial pressure in the rest of the tank assembly 10. The gas pump 26 is preferably adapted to provide a gas mass flow into, or out of, the tank assembly 10. The tank assembly 10 preferably comprises metering means for determining e.g. a pressure in the tank assembly. In the tank assembly 10 illustrated in Fig.
  • the metering means comprises a pressure gauge 30 within the tank assembly 10, but the metering means may be constituted by other gauges, and in some implementations of the tank assembly 10, additional physical properties may preferably be measured, such as a gas mass flow through the gas pump and the temperature within and/or outside of the tank assembly 10.
  • the invention relates to a method for estimating the leakage area in a vehicle tank assembly 10 by varying the pressure in the tank assembly by applying the gas mass flow through the gas pump 26 during an area estimation time period.
  • the method further comprises the steps of establishing an instantaneous gas mass flow relation of the gas in the tank assembly 10 in which relation the leakage area A leak is an unknown parameter.
  • the aforesaid establishment is performed for each of a plurality of time instants during the area estimation time period, hence a plurality of gas mass flow relations are obtained.
  • the method further comprises the step of estimating the leakage area A leak by utilizing the instantaneous gas mass flow relations.
  • the method of the invention may be carried out by either increasing or decreasing the pressure within the tank assembly 10.
  • the gas pumped by utilizing the gas pump 26 is preferably air.
  • estimation of the leakage area A leak is executed by arranging the instantaneous gas mass flow relation of the gas in an equations system and determining the leakage area A leak by utilizing a least-squares method.
  • the arrangement of the gas mass flow relation of the gas is solved by utilizing a recursive least-squares method.
  • each of the instantaneous gas mass flow relation is an equality based on an ideal gas law.
  • a first side of the equality comprises a first entity minus a second entity.
  • the first entity comprises a product of: a change of pressure ⁇ p in the tank assembly 10 from the start of the area estimation time period to the time instant t , and the initial gas volume V 0 of the tank assembly 10.
  • the second entity comprises a product of: the accumulated leakage flow q leak through the leakage 18 multiplied by a temperature T of the gas in the tank assembly during a time period from the start of the area estimation time period t 0 to the time instant t ; and the specific gas constant r of the gas, wherein in which leakage flow q leak , the leakage area A leak is an unknown parameter.
  • a second side of the equality may comprise a third entity, wherein the third entity comprises a product of: the accumulated gas mass flow q pump from the gas pump 26 multiplied by the temperature T of the gas in the tank assembly 10 during a time period from the start of the area estimation time period to to the time instant t and the specific gas constant r of the gas.
  • the second side of the equality comprises a term which relates to a change in volume of the tank assembly 10.
  • the change in volume may be considered, such that the second side of the equality may comprise a fourth entity, subtracted from said third entity, wherein the fourth entity comprises a product of: the pressure p in the tank assembly 10 at the time instant t and a change in volume ⁇ V of the tank assembly from the start of the area estimation time period to to the time instant t .
  • the abovementioned volume change function may be empirically determined, for instance obtained by pressurizing the tank system for a plurality of different pressures and temperatures and measuring the change in volume.
  • the change in volume for a plurality of different pressures and temperatures may be obtained by structural analyzes, such as FE analyses, of the tank system. Irrespective of how the change in volume as a function of pressure and temperature has been determined, i.e. by experiments or analyses, the results are preferably tabulated and stored in a storage unit.
  • the change in volume for an actual pressure and temperature may be obtained by utilizing an interpolation method on the aforementioned tabulated data.
  • Eq. 12 a gas equality which is valid for a time instant during the area estimation time period, wherein t ⁇ [ t 0 t end ].
  • the parameter ⁇ comprising the sought leakage area A leak
  • the parameter ⁇ can be determined using conventional techniques, such as a least-squares method.
  • a recursive least-squares method is used.
  • a fifth entity is added to the first side of the equality, wherein the fifth entity comprises a product of: an accumulated gas mass flow q canister from the canister 24 multiplied by the temperature T of the gas in the tank assembly 10 during a time period from the start of the area estimation time period t 0 to the time instant t ; and the specific gas constant r of the gas.
  • a sixth entity is added to the first side of the equality, wherein the sixth entity is representative of a pressure change due to evaporation of the liquid and/or dewing of the gas in the tank assembly during a time period from the start of the area estimation time period t 0 to the time instant t .
  • the pressure change is formulated as an additional gas mass flow q evapor .
  • the gas pump 26 of the tank assembly 10 is generally supplied with electrical power.
  • each of the change in pressure ⁇ p and the gas mass flow q pump through the gas pump 26, respectively is in one preferred embodiment of the inventive method estimated by a performance function of an applied pump electrical current I .
  • Each performance function has a set of performance coefficients.
  • gas mass flow q pump is used as an example in the description of the performance estimation portion of the preferred embodiment of the method of the invention. It should however be realized that the description is equally valid for the change in pressure ⁇ p .
  • each, of the performance functions is estimated by an affine performance function.
  • the electrical power is supplied to the gas pump 26 at a predetermined voltage U .
  • the performance of the gas pump 26 may differ for separate voltages U applied.
  • the pump assembly 34 comprises a reference opening 36 and a valve 38 for controlling the gas mass flow q pump .
  • the valve 38 is operable to guide the gas mass flow q pump at least either through the reference opening 36 or to an outlet opening 40 which outlet opening 40 may be in fluid communication with the tank assembly 10.
  • the pump assembly 34 of Fig. 2 further comprises an inlet opening 42 which in some implementations of the pump assembly 34 may be in fluid communication with the surrounding atmosphere.
  • the cross-sectional area of the reference opening 36 is preferably relatively small and is preferably less than 0.5 mm 2 , more preferably less than 0.2 mm 2 .
  • the reference opening 36 may be a cylindrical opening having a diameter of 0.5 mm.
  • the performance coefficients of the performance functions are established by a coefficient estimation method comprising the step of operating the valve 38 in order to guide the gas mass flow q pump through the reference opening 36 and determining a corresponding pump reference electrical current I ref and determining the performance coefficients of each of the performance functions depending on the corresponding pump reference electrical current I ref .
  • the performance estimation may be even further refined by a coefficient estimation method which comprises the step of operating the valve 38 in order to guide the flow q pump to the tank assembly 10 and determining an initial corresponding pump minimum electrical current I min , and determining the performance coefficients of each of the performance functions depending on the corresponding pump minimum electrical current I min .
  • a leakage area A leak may be estimated by utilizing the leakage estimation method and then comparing the estimated leakage area A leak to a predetermined threshold value.
  • the leakage testing method further comprises the step of transmitting a warning signal if the estimated leakage area A leak exceeds the predetermined threshold value and/or the step of transmitting an acceptance signal if the estimated leakage area A leak is lower than the predetermined threshold value.
  • the leakage estimation method and/or the leakage testing method may preferably be implemented in a computer program product.
  • a computer program product may comprise a computer program containing computer program code executable in a computer or a processor to implement at least one of the steps of a aforementioned methods.
  • the computer program product may preferably be stored on a computer-readable medium or a carrier wave.
  • the computer program product may preferably be stored in an electronic control unit (ECU) 32 and the ECU 32 may preferably be located within a vehicle, which vehicle comprises the vehicle tank assembly 10.
  • ECU electronice control unit
  • the method comprises the steps of, for each of a plurality of pump assemblies 34 and/or at least one pump assembly 34 at different time periods:
  • Fig. 3 illustrates the electrical current I applied to the gas pump 26 as a function of time, the pump electrical current I being denoted by lines 44.
  • the pump electrical current I being denoted by lines 44.
  • the valve 38 of the pump assembly 34 may preferably be further operated so that the gas mass flow q pump is guided out of the pump assembly 34. If the initial pressure out of the pump assembly 34 is significantly equal to the pressure at the inlet 42, a pressure difference between the inlet and outlet 42, 40 is substantially zero, resulting in a minimum of applied electrical current / to the pump, as indicated by area C in Fig. 3 .
  • This illustrates additional steps of a further embodiment of the estimation method which comprises the steps of operating the valve 38 in order to guide the flow q pump out of the pump assembly 34 and determining an initial corresponding pump minimum electrical current I min and generating the performance coefficient function, which is dependent on at least the pump minimum electrical current I min .
  • the pump electrical current / may remain at the minimum level or increase with time.
  • An increase in pump electrical current may indicate that the pump assembly is in fluid communication with a closed system, for example a tank assembly 10.
  • the performance coefficients of the affine performance function are preferably estimated by utilizing a least-squares method, more preferably a recursive least-squares method.
  • the aforementioned pump assembly 34 may preferably form a part of a vehicle tank assembly 10, wherein the pump assembly 34 is in fluid communication with the rest of the tank assembly 10. Then, an additional performance of the pump assembly 10 may be a resulting change in pressure ⁇ p in the tank assembly 10 when the pump 26 of the pump assembly 34 is operated.
  • the performance coefficient functions may preferably be used when estimating the output of a pump assembly. However, since this technique has been previously described with respect to the leakage area estimation methods, it will not be further detailed here.
  • gas mass flow relation used in the aforementioned leakage area estimation method could take into account the compressibility of the gas.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Examining Or Testing Airtightness (AREA)

Claims (30)

  1. Procédé pour estimer une aire de fuite (Afuite ) dans un système (10) de réservoir de véhicule, ledit système (10) de réservoir comprenant un réservoir (12), une pompe à essence (26) en communication fluidique avec le reste dudit système (10) de réservoir, et des moyens (30) pour déterminer une pression (p) dans ledit système (10) de réservoir et un débit massique d'essence (qpompe ) à travers la pompe à essence (26), le procédé comprenant les étapes consistant à :
    - faire varier la pression (p) dans ledit système (10) de réservoir en appliquant ledit débit massique d'essence (qpompe ) à travers ladite pompe à essence (26) durant une période temporelle d'estimation d'aire ;
    caractérisé en ce que le procédé comprend les étapes consistant à :
    - pour chacun d'une pluralité d'instants durant ladite période temporelle d'estimation d'aire, établir une relation de débit massique d'essence instantané de l'essence dans ledit système (10) de réservoir, relation dans laquelle ladite aire de fuite (Afuite ) est un paramètre inconnu ; et
    - estimer ladite aire de fuite (Afuite ) en utilisant lesdites relations de débit massique d'essence instantané.
  2. Procédé selon la revendication 1, dans lequel ladite estimation de ladite aire de fuite (Afuite ) est exécutée en organisant lesdites relations de débit massique d'essence instantané de l'essence en un système d'équations et en déterminant ladite aire de fuite (Afuite ) par une méthode des moindres carrés.
  3. Procédé selon la revendication 2, dans lequel ledit système desdites relations de débit massique d'essence de l'essence est résolu par une méthode des moindres carrés récursive.
  4. Procédé selon l'une quelconque des revendications précédentes, dans lequel chaque dite relation de débit massique d'essence instantané est une égalité basée sur une loi des gaz parfaits.
  5. Procédé selon la revendication 4, dans lequel un premier membre de ladite égalité comprend une première entité moins une deuxième entité,
    - ladite première entité comprenant un produit: d'une variation de pression (Δp) dans ledit système (10) de réservoir entre le début de ladite période temporelle (t0 ) d'estimation d'aire et ledit instant (t), et du volume initial d'essence (V0 ) dudit système de réservoir d'essence (10) ;
    - ladite deuxième entité comprenant un produit : du débit de fuite cumulé (qpompe ) à travers ladite fuite (18) multiplié par une température (T) de ladite essence dans ledit système (10) de réservoir d'essence durant une période temporelle entre le début de ladite période temporelle (t0 ) d'estimation d'aire et ledit instant (t) ; d'une constante de gaz spécifique (r) de ladite essence, ladite aire de fuite (Afuite ) étant un paramètre inconnu dans ledit débit de fuite (qfuite ).
  6. Procédé selon la revendication 5, dans lequel ledit débit de fuite (qfuite ) est déterminé par une mesure de fuite, ladite mesure de fuite étant un produit: de ladite aire de fuite inconnue (Afuite ) et de la valeur d'une fonction de fuite (ffuite ), ladite fonction de fuite (ffuite ) étant une fonction d'au moins la pression (p) dans ledit système (10) de réservoir.
  7. Procédé selon la revendication 6, dans lequel ladite fonction de fuite (ffuite ) est en outre une fonction de la pression d'un milieu entourant ledit système (10) de réservoir et/ou de ladite température (T) de ladite essence dans ledit système (10) de réservoir et/ou d'une température dudit milieu environnant.
  8. Procédé selon l'une quelconque des revendications 5 à 7, dans lequel :
    - un deuxième membre de ladite égalité comprend une troisième entité, dans laquelle
    • ladite troisième entité comprend un produit: d'un débit massique d'essence cumulé (qpompe ) de la pompe à essence (26) multiplié par ladite température (T) de ladite essence dans ledit système (10) de réservoir durant une période temporelle entre le début de ladite période temporelle d'estimation d'aire (t0 ) et ledit instant (t) ; et de ladite constante de gaz spécifique (r) de ladite essence.
  9. Procédé selon la revendication 8, dans lequel :
    - ledit deuxième membre de ladite égalité comprend de plus une quatrième entité soustraite de ladite troisième entité,
    • ladite quatrième entité comprenant un produit: de ladite pression (p) dans ledit système (10) de réservoir audit instant (t) et d'une variation de volume (ΔV) dudit système (10) de réservoir entre le début de ladite période temporelle d'estimation d'aire (t0) et ledit instant (t).
  10. Procédé selon la revendication 9, dans lequel ladite variation de volume (ΔV) est modélisée par une fonction d'au moins la température de l'essence (T) et de sa pression (p) dans le système (10) de réservoir.
  11. Procédé selon l'une quelconque des revendications 5 à 10, dans lequel ledit système (10) de réservoir comprend un absorbeur (24) en communication fluidique avec ledit réservoir (12), une cinquième entité étant ajoutée audit premier membre de ladite égalité,
    - ladite cinquième entité comprenant un produit: du débit massique d'essence cumulé (qabsorbeur ) depuis ledit absorbeur (24) multiplié par ladite température (T) de ladite essence dans ledit système (10) de réservoir durant une période temporelle entre le début de ladite période temporelle d'estimation d'aire (t0 ) et ledit instant (t) ; et de la constante de gaz spécifique (r) de ladite essence.
  12. Procédé selon l'une quelconque des revendications 5 à 10, dans lequel une sixième entité est ajoutée audit premier membre de ladite égalité,
    - ladite sixième entité étant représentative d'une variation de pression due à l'évaporation d'un liquide (14) et/ou à la condensation de ladite essence dans ledit système (10) de réservoir durant une période temporelle entre le début de ladite période temporelle d'estimation d'aire (t0 ) et ledit instant (t).
  13. Procédé selon l'une quelconque des revendications précédentes, dans lequel ladite température d'essence (T) dans ledit système (10) de réservoir est supposée constante pendant toute la période temporelle d'estimation d'aire.
  14. Procédé selon l'une quelconque des revendications précédentes, dans lequel ladite pompe à essence (26) est alimentée en électricité, dans lequel respectivement ladite variation de pression (Δp) et ledit débit massique d'essence (qpompe ) à travers ladite pompe à essence (26), sont estimés chacun par une fonction de performance d'un courant électrique de pompe appliqué (I), chaque fonction de performance ayant un ensemble de coefficients de performance.
  15. Procédé selon la revendication 14, dans lequel chacune desdites fonctions de performance est estimée par une fonction de performance affine.
  16. Procédé selon la revendication 14 ou 15, dans lequel lesdits coefficients de performance de chacune desdites fonctions de performance affines dépendent au moins d'une tension électrique (U) de pompe fournie à ladite pompe à essence (26).
  17. Procédé selon l'une quelconque des revendications 14 à 16, dans lequel ledit système (10) de réservoir comprend une ouverture de référence (36) et une vanne à essence (38) pour contrôler ledit débit massique d'essence (qpompe ), ladite vanne (38) étant utilisable pour diriger ledit débit massique d'essence (26) au moins à travers ladite ouverture de référence (36) ou vers ledit système (10) de réservoir, dans lequel lesdits coefficients de performance desdites fonctions de performance sont établis par une méthode d'estimation de coefficients comprenant l'étape consistant à actionner ladite vanne (38) pour diriger ledit débit à travers ladite ouverture de référence (36) et déterminer un courant électrique de référence de pompe correspondant (Iref ) et déterminer lesdits coefficients de performance de chacune desdites fonctions de performance en fonction dudit courant électrique de référence de pompe correspondant (Iref ).
  18. Procédé selon l'une quelconque des revendications 14 à 17, dans lequel lesdits coefficients de performance desdites fonctions de performance sont établis par un procédé d'estimation de coefficient comprenant l'étape consistant à actionner ladite vanne (38) pour diriger ledit débit (qpompe ) vers ledit système (10) de réservoir et déterminer le courant électrique minimum de pompe correspondant initial (Imin ), et déterminer lesdits coefficients de performance de chacune desdites fonctions de performance en fonction dudit courant électrique minimum de pompe correspondant (Imin ).
  19. Procédé pour tester une fuite dans un système de réservoir de véhicule, dans lequel ledit procédé de test de fuite comprend les étapes consistant à estimer une aire de fuite (Afuite ) selon l'une quelconque des revendications précédentes.
  20. Procédé de test de fuite selon la revendication 19, comprenant de plus l'étape consistant à comparer ladite aire de fuite estimée (Afuite ) avec une valeur de seuil prédéterminée.
  21. Procédé de test de fuite selon la revendication 20, comprenant de plus l'étape consistant à transmettre un signal d'avertissement si ladite aire de fuite estimée (Afuite) dépasse ladite valeur de seuil prédéterminée et/ou l'étape consistant à transmettre un signal d'acceptation si ladite aire de fuite estimée est inférieure à ladite valeur de seuil prédéterminée.
  22. Produit programme informatique, caractérisé en ce qu'il comprend un programme informatique contenant un code programme informatique exécutable sur un ordinateur ou dans un processeur pour mettre en oeuvre toutes les étapes d'un procédé selon l'une quelconque des revendications 1 à 21, ledit produit étant stocké sur un médium lisible par un ordinateur ou sur une onde porteuse.
  23. Unité de commande électronique (32), caractérisée en ce qu'elle comprend un produit programme informatique selon la revendication 22 et agencé pour exécuter un procédé d'estimation d'aire de fuite selon l'une quelconque des revendications 1 à 18 et/ou un procédé de test de fuite selon l'une quelconque des revendications 19 à 21.
  24. Véhicule, caractérisé en ce qu'il comprend une unité de commande électronique (32) selon la revendication 23.
  25. Procédé selon l'une quelconque des revendications 17 et 18, dans lequel ledit procédé comprend en plus une étape de détermination desdits coefficients de performance pour ladite variation de pression (Δp) et ledit débit massique d'essence (qpompe) en analysant une pluralité de systèmes (34) de pompe et/ou au moins un système (34) de pompe pendant différentes périodes temporelles, chaque système (34) de pompe faisant partie d'un système (10) de réservoir de véhicule et comprenant une pompe (26) à essence, dans lequel chaque système (34) de pompe comprend ladite ouverture (36) de référence et ladite vanne d'essence (38) pour contrôler ledit débit massique d'essence (qpompe ), ladite vanne (38) étant utilisable pour diriger ledit débit massique d'essence (qpompe ) au moins à travers ladite ouverture de référence (36) ou à travers une ouverture de sortie (40), caractérisé en ce que le procédé comprend les étapes consistant à :
    - pour chacune de ladite pluralité de systèmes (34) de pompe et/ou ledit au moins un système (34) de pompe pendant différentes périodes temporelles :
    • mesurer ladite performance pour une pluralité de courants électriques de pompe appliqués (I) ;
    • estimer ladite performance par ledit courant électrique de pompe appliqué (I) et déterminer ainsi des coefficients de performance pour une fonction de performance ;
    • actionner ladite vanne (38) afin de diriger ledit débit (qpompe ) à travers ladite ouverture de référence (36) et déterminer le courant électrique de référence de pompe correspondant (Iref ) ;
    - pour chaque coefficient de performance, générer une fonction de coefficient de performance qui dépend d'au moins ledit courant électrique de référence de pompe (Iref ).
  26. Procédé selon la revendication 25, dans lequel le procédé comprend de plus les étapes consistant à :
    - pour chacune de ladite pluralité de systèmes (34) de pompe et/ou ledit système (34) de pompe au nombre d'au moins un pendant différentes périodes temporelles :
    • actionner ladite vanne (3 8) pour diriger ledit débit (qpompe ) à travers ladite ouverture de sortie (40) et déterminer un courant électrique minimum de pompe correspondant initial (Imin ) ;
    - pour chaque coefficient de performance, générer une fonction de coefficient de performance qui dépend d'au moins ledit courant électrique minimum de pompe (Iref ).
  27. Procédé selon la revendication 25 ou 26, dans lequel le procédé comprend de plus les étapes consistant à :
    - pour chacune de ladite pluralité de systèmes (34) de pompe et/ou ledit au moins un système (34) de pompe pendant différentes périodes temporelles :
    • déterminer une tension électrique de pompe (U) ;
    - pour chaque coefficient de performance, générer une fonction de coefficient de performance qui dépend d'au moins ladite tension électrique de pompe (U).
  28. Procédé selon l'une quelconque des revendications 25 à 27, dans lequel le procédé comprend de plus l'étape consistant à :
    - estimer chacune desdites fonctions de performance par une fonction de performance affine.
  29. Procédé selon la revendication 28, dans lequel le procédé comprend de plus l'étape consistant à :
    - estimer lesdits coefficients de chacune desdites fonctions de performance affines par une méthode des moindres carrés.
  30. Procédé selon la revendication 29, dans lequel le procédé comprend de plus l'étape consistant à :
    - estimer lesdits coefficients de chacune desdites fonctions de performance affines par une méthode des moindres carrés récursive.
EP20060120073 2006-09-04 2006-09-04 Diagnostic de fuite de gaz Not-in-force EP1895144B1 (fr)

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DE200660013630 DE602006013630D1 (de) 2006-09-04 2006-09-04 Gasleck-Diagnose
EP08105249.0A EP1998037B1 (fr) 2006-09-04 2006-09-04 Diagnostic de fuite de gaz
EP20060120073 EP1895144B1 (fr) 2006-09-04 2006-09-04 Diagnostic de fuite de gaz

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DE102021128688B3 (de) * 2021-11-04 2022-11-24 Eagle Actuator Components Gmbh & Co. Kg Modul zur Erfassung einer Leckage einer Anordnung und Verfahren zur Erfassung einer Leckage einer Anordnung

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DE19713085C2 (de) * 1997-03-27 2003-06-12 Siemens Ag Verfahren zum Überprüfen der Funktionstüchtigkeit einer Tankentlüftungsanlage für ein Kraftfahrzeug
DE69802954D1 (de) * 1997-10-02 2002-01-24 Siemens Canada Ltd Verfahren zur temperatur-korrektur und untersystem für eine anordnung zur verdampfungsleck-detektion von fahrzeugen
US5974861A (en) * 1997-10-31 1999-11-02 Siemens Canada Limited Vapor leak detection module having a shared electromagnet coil for operating both pump and vent valve
US6301955B1 (en) * 1999-01-27 2001-10-16 Siemens Canada Limited Driver circuit for fuel vapor leak detection system
US6216674B1 (en) * 2000-02-22 2001-04-17 Jaguar Cars Limited Fuel system vapor integrity testing with temperature compensation
JP3919059B2 (ja) * 2000-06-14 2007-05-23 スズキ株式会社 内燃機関の空燃比制御装置
JP3876722B2 (ja) * 2001-06-28 2007-02-07 トヨタ自動車株式会社 内燃機関の蒸発燃料処理装置
DE10204132B4 (de) * 2002-02-01 2012-03-15 Robert Bosch Gmbh Verfahren und Vorrichtung zur Dichtheitsprüfung eines Behältnisses
DE10209483B4 (de) * 2002-03-05 2006-07-06 Robert Bosch Gmbh Verfahren zur Prüfung der Funktionsfähigkeit einer Tankentlüftungsanlage und Tankentlüftungsanlagen bei Kraftfahrzeugen
JP2004232521A (ja) * 2003-01-29 2004-08-19 Denso Corp 蒸発燃料処理装置のリークチェック装置
JP4117839B2 (ja) * 2003-04-23 2008-07-16 株式会社デンソー エバポガスパージシステムのリーク診断装置
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JP3923473B2 (ja) * 2003-05-21 2007-05-30 本田技研工業株式会社 蒸発燃料処理装置の故障診断装置
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DE60312851T2 (de) * 2003-08-28 2007-12-06 Ford Global Technologies, LLC, Dearborn Verfahren und Vorrichtung zur Leckdiagnose in einem Behälter

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EP1895144A1 (fr) 2008-03-05
EP1998037A2 (fr) 2008-12-03
EP1998037B1 (fr) 2014-12-10
DE602006013630D1 (de) 2010-05-27
EP1998037A3 (fr) 2013-05-29

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