• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The method involves determining a composition of a fuel mixture from a signal differently based on components of exhaust gas for pumping current (60) or a pumping current variation of a pumping cell of an exhaust gas probe (10) e.g. broadband lambda probe, of an internal combustion engine. The exhaust gas probe is installed in an exhaust gas channel of the engine. A defined mixture enriched fuel is provided periodically for known air mass. An independent claim is also included for a device for determining composition of a fuel mixture for operating an internal combustion engine.
    公开号:SE534605C2
    申请号:SE0950448
    申请日:2009-06-12
    公开日:2011-10-18
    发明作者:Jens Schneider；Lothar Diehl；Dirk Liemersdorf；Thomas Seiler；Thomas Classen
    申请人:Bosch Gmbh Robert；
    IPC主号:
    专利说明:

    534 605 2 based there are fuel type sensors that determine the fuel composition using the dielectric properties of the fuel mixture. Other fuel sensors use the varying electrical conductivity or the different optical properties of fuels such as the different refractive indices.
    DE 41 12 574 describes a fuel supply system for an internal combustion engine in which the operating state of the internal combustion engine is registered and the amount of fuel to be supplied is controlled corresponding to the results of this registration. It is hereby provided that the fuel supply system comprises a fuel type registration means for fuel type registration and a calculator for calculating one of the fuel type, corresponding theoretical air / fuel ratio in accordance with the registration result of the fuel type registration means and that the amount of fuel to be supplied from the fuel theoretical air-fuel ratio as target-air-fuel ratio. In this case, it may be provided that the fuel type registration means registers the fuel type by measuring at least either the refractive index. the dielectric constant or molar heat of the fuel in fl surface state.
    An exact determination of the ethanol content is difficult according to the state of the art because water can also be included in the fuel mixture. An additional sensor with corresponding control is therefore necessary for ethanol detection. These ethanol sensors are expensive and error prone.
    Furthermore, it is known that the characteristic fat curve of flat broadband lambda probes strongly depends on the molecular mass m of the indiffusing fat gas and the diffusion constant D is proportional to the root of m (Physik Journal No. 5 - 2006, pp. 33-38).
    Such broadband lambda probes are known, for example, from DE 102005061890 A1 as well as from DE 102005043414 A1, DE 102005061890 A1 describing the construction of a broadband lambda probe in which the use of certain chemical elements according to the invention is envisaged in its construction.
    From DE 102005043414 A1 a method is known for determining the gas components in the exhaust gas from an internal combustion engine, in which a conclusion is drawn about the concentration of individual components of the exhaust gas, in particular at least one gas component separated from oxygen, from the signal from an exhaust gas stream. 534 605 3 from a discrete level probe arranged in the exhaust stream. Similarly, a corresponding device is described in this document.
    The task of the invention is to provide a method and a device which, by using exhaust probe functions of an exhaust probe, support a fuel analysis in Flex-Fuel mixtures and in this case are able to replace additional ethanol sensors.
    Advantages of the invention The invention object of the process is solved in that the composition of the fuel mixture is determined from one of the components of the exhaust gas differently dependent signal for a pump current or a pump current change of a pump cell of the exhaust gas. In particular, unburned fuels are oxidized resp. fuel components at the outer electrode or at the measuring electrode of the exhaust probe, whereby the output signal from the exhaust probe is affected. Thereby, different fuels, for example alcohol and petrol, differ in their oxidation behavior and in their oxidation kinetics and thus in their influence on the output signal from the exhaust probe. With the aid of the output signal from the exhaust probe, a conclusion can therefore be drawn about the composition of the fuel mixture. This can be used regardless of engine temperature or engine condition. It is advantageous here that the composition of the fuel mixture can be determined with the aid of exhaust gases which are in any case provided in modern internal combustion engines and thus no additional components and sensors are required. This is advantageous in terms of simplification and an associated cost reduction. In a preferred process variant, the exhaust gas probe is supplied at least occasionally with a certain fat fuel mixture at known air mass and an ethanol content of the fuel is determined from the pump flow at the known air mass flow, known fat gas quantity and known engine combustion temperature. Such "grease excursions" are already used in internal combustion engines for diagnostic purposes or in diesel engines for the regeneration of catalysts or particulate matter and can therefore be used to determine the fuel composition. The water which may be included in this case is not involved as inert gas 534 605 In a preferred variant of the process, a certain fatty fuel mixture is added to known air mass at periodic distances, ie clockwise.
    In this case, a conclusion is drawn, especially from the hinge components CO and H2 in the exhaust gas, about the original relative composition of the combusted fuel. In this case, it can be assumed that the ratio of CO and H2 is used as a measure of the relative composition of the fuel. Their shares differ depending on the composition of the fuel. In practice, there is a sensitivity that moves between the joint components CO and H2. From their actual size, taking into account the air mass flow and the amount of injection, the conclusion about the fuel composition follows.
    A preferred process variant envisages that the fatty fuel mixture is fed to the exhaust probe by means of the fuel metering device as post-injection. fi d cold engine resp. exhaust pipes, unburned and also non-oxidized fuel components can reach the exhaust probe so that the individual sensitivities of the exhaust gas with respect to the components typical of petrol and ethanol are elevated.
    In this case, it can also be assumed that, in addition to the joint components CO and H2 in the exhaust gas, the joint components of unburned petrol and ethanol hydrocarbons are also determined and compared. The amount of post-injection must be known and (it must) be ensured that it is large enough to characterize the gas composition in the area of the installation position of the exhaust probe.
    Without additional components and without an effect on the operation of the internal combustion engine, the exhaust probe can also be supplied with unburned fuel by supplying the fuel mixture to the internal combustion engine by means of the fuel metering device during engine braking. Especially with separately igniting internal combustion engines, no ignition takes place during engine braking so that the fuel resp. the fuel mixture can pass the combustion chamber unburned.
    In this case, a damper flap is preferably opened during the fuel supply during engine braking of the internal combustion engine in order to achieve a cold engine condition. Such test injections are also used, for example, for drive calibration of the injection valves in diesel internal combustion 534 B05 engines. Likewise, the fuel can, after re-injection, pass unburned, as is used in the regeneration of an oxidation catalyst.
    A process variant presupposes that the proportion of hydrogen is determined by changing the pump flow at different exhaust pressures. The effect is that the free mean path length of a gas depends on its mass and the ratio of gas phases to Knudsen diffusion is a function of the molecular mass ratio at a certain lambda value.
    The reaction of the sensor current to periodic pressure variations in the exhaust gas depends on the flow properties of the gas molecules and thus on the molecular masses that occur, which vary depending on the fuel composition and the exhaust composition. Therefore, in a further process variant, it may be assumed that in the case of periodic pressure variations at known lambda value and known pressure amplitudes, the relative hydrogen content is determined from the amplitude of the pump flow or from its phase shift to the pressure variations. This creates more CO2 with a fat gas with a high hydrocarbon content, so that the dispersion cross-sectional increase of the carrier gas is higher than with a high hydrogen content. The curvature of the characteristic fat curve therefore increases. In addition, the gas flow decreases at pressure pulses at large molecules as the viscosity increases. The additional outflow through the arising inert gas in the fat area also reduces the dynamic pressure dependence.
    As slow as possible catalytic oxidation of the unburned fuel at the outer electrode and the measuring electrode of the exhaust probe, respectively, leads to an improved tilt reliability and measuring accuracy in determining the composition of the fuel mixture by means of the output signal from the exhaust probe. Therefore, it may be anticipated that the pump current change will be determined at differently set sensor temperatures. A reduced temperature of the exhaust probe and thus the outer electrode and the measuring electrode, for example, leads to a reduced oxidation rate of the fuel component. A comparison of the measured values at different sensor temperatures can increase the accuracy of the determination of the fuel composition. In connection with an at least partial and / or periodic lowering of the temperature of the outer electrode, in combination with a further mounted platinum surface at the outer electrode for precatalysis, the sensitivity of the exhaust probe can be further increased. 534 B05 6 A second method variant predicts that the exhaust probe is regulated with its pump cell at a lambda value kz 1 while the fuel metering is controlled in such a way that at a positive pump voltage (approx. 600 mV) the pump current returns to zero and connecting at an unchanged injection amount with the Nernst voltage for a lambda value x = 1. The exact value of the setting lambda value is determined from the diffusion properties of a diffusion barrier of the exhaust probe, which allows hydrogen and oxygen to diffuse at different speeds. The measured Nemst voltage at this lambda value is determined from the diffusion constant by an outer protective layer of the exhaust probe. As the outer protective layer separates hydrogen and oxygen differently from the diffusion barrier of the exhaust probe, a voltage is set which does not exactly correspond to a lambda value of 7. = 1, but depending on the type of fat gas deviates from it.
    With regard to the task of the device, it is envisaged as a solution that the exhaust probe is a broadband lambda probe which is arranged close to the engine, in the direction of the exhaust stream in front of a first catalyst and that the exhaust probe is at least occasionally supplied with a certain fat fuel mixture. Broadband lambda probes are already commonly used today in the exhaust duct of internal combustion engines. Such an exhaust probe has a pump current which is different from the components of the exhaust gas and their proportion in the exhaust gas and a pump current change, respectively, and can therefore be used in the corresponding coupling and evaluation of the pump current and the pump current change in a control unit without using additional sensors.
    The method and / or device can be used cost-effectively to determine the composition of a gasoline-ethanol-fuel mixture and / or a gasoline / methanol-fuel mixture and / or a gasoline / ethanol / methanol fuel mixture in internal combustion engines which can be operated with regenerative fuels of the kind previously mentioned.
    The accuracy of the determination of the composition of the fuel mixture by means of exhaust sensors depends on various influencing quantities, including from the exhaust sensor used. Even an accuracy better than 30% can be used as a supplementary index to software algorithms with which already today the composition of the fuel mixture is determined according to different procedures. With an accuracy better than 10%, a low quality ethanol sensor can be completely replaced, with an accuracy better than 5% a high quality ethanol sensor according to the state of the art of today. Therefore, it can be assumed that the determination of the composition of the fuel mixture takes place exclusively from the signal of the exhaust probe or is carried out in combination with other methods for determining the composition of the fuel mixture.
    Brief description of the drawings The invention is explained in more detail below with the aid of the exemplary embodiment described in the figures. It shows: Fig. 1a and Fig. 1b in a schematic description a broadband Iambda probe as an exhaust probe with different exhaust compositions and Fig. 2 a diagram, the relationship between the oxygen content of the exhaust gas and a pump flow of the exhaust probe for different components of the exhaust.
    Embodiments of the Invention Figs. 1a and Fig. 1b show in a schematic representation an exhaust probe 10 which is designed as a broadband Iambda probe and on the one hand is filled with a fat exhaust 20 (Fig. 1a) and on the other hand with a lean exhaust 30 ( Fig. 1b).
    The exhaust probe 10 is then arranged close to the engine in an exhaust duct of an internal combustion engine in the flow direction of the exhaust gas in front of a catalyst. The internal combustion engine has an intake duct with an air mass meter with which the mass of the air supplied to the internal combustion engine is determined. Immediately in front of the internal combustion engine, a fuel metering device is provided. The fuel metering device makes it possible to supply certain amounts of a fuel mixture to the internal combustion engine. The internal combustion engine can be designed as an Otto engine that is operated in Flex-Fuel operation with fuel mixtures of petrol and alcohol and methanol, respectively. In this case, the fuel mixture is sprayed immediately in front of the inlet valve of the internal combustion engine into the inlet duct and is supplied to the internal combustion engine together with the intake air. 534 B05 The exhaust probe 10 which, for example, is described in DE 102005061890 A1 comprises a pump cell with an outer electrode 12 and an inner electrode 17 as well as a so-called inner cell (also referred to as a sensor cell) with a measuring electrode 18 and a reference electrode 19. The exhaust probe is in rule built in planar technology from fast your fixed electrolyte layers 11. Furthermore, a heating device embedded in an insulation for heating the sensor element is provided (not shown in the figure). The exhaust gas 20, 30 can be supplied through an opening 14 in the form of a bore and through a diffusion barrier 15 into a measuring chamber 16. In the measuring chamber 16, the inner electrode 17 of the pump cell as well as the measuring electrode 18 of the inner cell are arranged. The outer electrode 12 has a protective layer 13 on the outer side of the exhaust probe 10 facing the exhaust gas 20, 30. The reference electrode 19 is arranged in a reference air duct which is filled with ambient air. A potential difference, the so-called Nernst voltage 70 between the measuring electrode 18 and the reference electrode 19, is measured across the downstream cell. A voltage is applied to the outside of the pump cell.
    This creates a current referred to as pump current 60 with which - polarity-dependent - oxygen ions are transported.
    An electronic control circuit causes the pump cell to always supply resp. removes just as much oxygen in the form of Oz ions of the exhaust volume, which is in contact with the measuring space 16 over the diffusion barrier 15, that a lambda value of I. = 1 settles in the measuring space 16 whereby in case of lean exhaust gas (in case of excess air) oxygen is pumped away and oily exhaust gas, on the other hand, is supplied with oxygen. The pump current 60 set by the control circuit depends on the air number of lambda in the exhaust gas and forms the output signal of the broadband lambda probe. The pump flow 60 is in the case of lean exhaust gas 20, in which in particular 02 and also NO occur as hinge components, positive and in the case of fatty exhaust 30 with the hinge components CO, H2 and HC (hydrocarbons), negative.
    The pump flow 60 depends primarily on the air number k of the exhaust gas, but this is also affected by a varying exhaust gas composition at the same k. This influence is based on different diffusion coefficients at the diffusion barrier at certain exhaust components. So, especially in the fat area, the ratio of CO to H2 has an effect which again depends on the fuel composition. 534 605 Fig. 2 shows in a diagram the relationship between the oxygen content of the exhaust gas and the pump flow 60 of the broadband lambda probe used as exhaust gas probe 10 for different components of the exhaust gas. The pump flow 60 is depicted on the one hand depending on a percentage oxygen content 40 in lean exhaust gas 30 as well as from a percentage oxygen deficit 50 in fat exhaust gas 20 and on the other hand from a resulting lambda value 80 which in the diagram shown is in the range between approx. 0.5 (extremely fat) to 7. ß 20 (extremely lean). In different characteristic curves 90, the processes are depicted for different joint components. In the area of lean exhaust gas 30, only the characteristic O 2 curve 91 is depicted, which extends in the first quadrant of the diagram, i.e. at positive pump current 60 and excess oxygen resp. percentage oxygen content 40. In the range of fatty exhaust 20 and negative pump current 60 (ie in the third quadrant of the diagram) the characteristic curves of the joint components CO, H2, CH., and C3H6 92, 93, 94, 95 are depicted which differ significantly so that these can be evaluated.
    According to the invention, it is then assumed that the exhaust gas probe 10 for determining the composition of the fuel mixture is occasionally, in part, supplied with extremely greasy exhaust gas in the form of unburned or at least partially combusted fuel mixture. The fuel composition is determined, for example, during separate diagnostic phases, for example during the engine braking phase of the internal combustion engine or during the hot-running phase of the internal combustion engine in the form of a post-injection, using differences in pump flow 60 when using fuel mixtures of different composition. evaluated against a known reference. For determining the fuel composition of the supplied fuel mixture, even with broadband lambda probes, lower temperatures of the exhaust probe 10 are advantageous. Temperature ranges from 550 ° C to 700 ° C and 400-550 ° C are suitable.
    The process supports the precise and reliable determination of the composition of a fuel mixture, in the case of Flex-Fuel operation-driven internal combustion engines with existing components. Especially when using a broadband lambda probe, additional sensors can be dispensed with, which entails cost advantages.
    权利要求:
    Claims (16)
    [1]
    A method for determining the composition of a fuel mixture of a first and at least a second fuel for operating an internal combustion engine, the internal combustion engine having a fuel metering device and at least one exhaust probe (10) in an exhaust duct of the internal combustion engine, characterized in that (10) a certain fatty exhaust gas is occasionally supplied in the form of unburned or at least partially unburned fuel mixture and that the composition of the fuel mixture is determined from a signal for a pump stream (60) or depending on the components of the exhaust gas or a pump current change of a pump cell of exhaust probe (10)
    [2]
    Method according to claim 1, characterized in that the exhaust gas probe (10) is supplied to the determined fatty fuel mixture at known air mass and that an ethanol content in the fuel is determined from the pump stream (60) at the known air mass stream. known amount of fat gas and known engine combustion temperature.
    [3]
    Process according to Claim 1 or 2, characterized in that a certain fatty fuel mixture is supplied at known air masses at periodic intervals.
    [4]
    Method according to one of Claims 1 to 3, characterized in that a conclusion is drawn from the joint components CO and H 2 in the exhaust gas as to the original relative composition of the combusted fuel.
    [5]
    Process according to Claim 4, characterized in that the ratio of CO and H 2 is used as a measure of the relative composition of the fuel.
    [6]
    Method according to one of Claims 1 to 5, characterized in that the determined fatty fuel mixture is supplied to the exhaust probe (10) by means of the fuel metering device as a post-injection or during an engine braking of the internal combustion engine.
    [7]
    Process according to Claim 6, characterized in that the addition of the determined fatty fuel mixture is carried out in the cold engine condition during the heating of the internal combustion engine. 534 605 ll
    [8]
    Process according to Claim 6 or 7, characterized in that, in addition to the lead components C0 and H2 in the exhaust gas, the joint components of unburned petrol and ethanol hydrocarbons are also determined and compared.
    [9]
    Method according to one of Claims 6 to 8, characterized in that a damper flap is opened during fuel supply during engine braking of the internal combustion engine.
    [10]
    Method according to one of Claims 1 to 9, characterized in that the proportion of hydrogen is determined by changing the pump flow (60) at different exhaust gas pressures.
    [11]
    Method according to one of Claims 1 to 10, characterized in that in the case of periodic pressure variations at known Iambda values and known pressure amplitudes, the relative hydrogen content is determined from the amplitude of the pump current (60) or from its phase shift to the pressure variations.
    [12]
    Method according to one of Claims 1 to 11, characterized in that the change in pump current is determined at differently set sensor temperatures.
    [13]
    Method according to one of Claims 1 to 12, characterized in that the exhaust probe (10) is regulated with its pump cell at a k-value (80) kz 1 by controlling the fuel metering in such a way that the pump current (60) at a positive pump voltage returns to zero, and subsequently, with unchanged injection amount, a Nemst voltage (70) is determined and compared with the Nemst voltage (70) for a k-value (80) 7. = 1.
    [14]
    Method according to one of Claims 1 to 13, characterized in that a broadband lambda probe is used as the exhaust probe (10).
    [15]
    Device for determining the composition of a fuel mixture of a first and at least a second fuel for operating an internal combustion engine, wherein at least one exhaust probe (10) is arranged in the exhaust duct of the internal combustion engine. that the exhaust probe (10) is a broadband lambda probe which is arranged motorized in the direction of the exhaust flow in front of a first catalyst and that a fuel metering device is provided, by means of which the exhaust probe (10) is at least occasionally deliverable a certain fatty fuel mixture, and that the exhaust gas probe (10) has one of the components of the exhaust gas and their share in the exhaust gas, differently dependent pump current (60) or a pump current change, and has an evaluation device for the pump current or the pump current change.
    [16]
    Use of the method according to any one of claims 1-14 and / or use of the device according to claim 15 for determining the composition of a petrol-ethanol-fuel mixture and / or a petrol / methanol-fuel mixture and / or a petrol / ethanol. / methanol-fuel mixture in an internal combustion engine for regenerative fuels.
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    同族专利:
    公开号 | 公开日
    FR2932846A1|2009-12-25|
    SE0950448L|2009-12-19|
    DE102008002493A1|2009-12-24|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2021123781A1|2019-12-20|2021-06-24|Loughborough University|Determining a proportion of hydrogen in a mixture of hydrogen and natural gas|DE4112574C2|1990-04-17|1994-06-09|Hitachi Ltd|Fuel supply systems for internal combustion engines|
    DE102005043414A1|2005-09-13|2007-03-15|Robert Bosch Gmbh|Method and device for determining the gas components in the exhaust gas of an internal combustion engine|
    DE102005061890A1|2005-12-23|2007-06-28|Robert Bosch Gmbh|Sensor unit e.g. lambda oxygen sensor, for determining e.g. oxygen portion, has layer with phosphor-bond unit for forming phosphor connection in measuring gas containing phosphor in powdered form, where layer is external protective layer|DE102010033336B4|2010-08-04|2013-01-17|Audi Ag|Method for regulating the composition of the exhaust gas of an internal combustion engine|
    DE102011005134A1|2011-03-04|2012-09-06|Robert Bosch Gmbh|Method for determining a content of alcohol in a fuel mixture|
    DE102018104258B4|2018-02-26|2021-03-25|Man Truck & Bus Se|Fuel determination technology|
    法律状态:
    2017-01-31| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    DE102008002493A|DE102008002493A1|2008-06-18|2008-06-18|Fuel mixture e.g. ethanol/petrol fuels mixture, composition determining method for e.g. petrol engine, involves determining composition of fuel mixture from signal differently based on components of exhaust gas|
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