• 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 invention relates to a method for determining the composition of a single fuel mixture of a first fuel and at least a second fuel displacement of an internal combustion engine, the fuels differing in their chemical and / or physical and / or combustion properties, wherein operating areas of the internal combustion engine are delimited from each other. and determining parameters which are dependent on the chemical and / or physical and / or combustion properties of the fuel mixture. In this case, ensuring that the first composition value of the fuel mixture is determined from a first parameter, that at least a second composition value of the fuel mixture is determined from at least a second parameter, that weighting factors for the composition values are specified depending on the estimation accuracy of the respective composition and composition. The fuel mixture is determined from a combination of the first composition value and at least the second composition value weighted by the associated weighting factors. The invention further relates to a corresponding device. The method and the device enable a cost-effective, accurate and reliable determination of the composition of fuel mixtures for premixes. .
    公开号:SE536301C2
    申请号:SE1050876
    申请日:2010-08-27
    公开日:2013-08-13
    发明作者:Martin Klenk；Stephan Uhl；Kai Jakobs；Pierre-Yves Crepin
    申请人:Bosch Gmbh Robert；
    IPC主号:
    专利说明:

    20 25 30 535 301 den. In the USA and in Europe, a mixture of 75-85% ethanol and 15-25% petrol is often used under the name E85. The internal combustion engines are designed so that they can be operated with both pure petrol and with blades up to E85, this is called "Flexifue | operation". For economical operation with low emissions of harmful substances at the same time as engine power, operating parameters in Flexifuel operation must be adapted to the current fuel mixture. For example, a stoichiometric air / fuel ratio is 14.7 parts by weight of air per proportion of gasoline, however, when using ethanol, an air content of 9 parts by weight must be set.
    In the case of if exifuel operation, due to the different temperature-dependent evaporation properties of ethanol and petrol at the start of the internal combustion engine, an adapted enrichment factor must be specified depending on the mixing ratio.
    The ignition timing must also be adjusted depending on the fuel mixture. Knowledge of the present fuel mixture ratio is thus of fundamental importance for the operation of the internal combustion engine.
    Different fuel type sensors, also called "fuel composition sensors", can be used to determine the composition of the fuel mixture. solvent which contains hydrogen ions and has a high, however dependent water content, dielectric constant.Gasoline, on the other hand, is an aprotic solvent with a small dielectric constant.Based on this basis, fuel type sensors Other fuel sensors use the different electrical conductivities or different optical properties of the fuels, such as different refractive indices. The disadvantage is that the use of fuel type sensors increases system costs. The correct functioning of the fuel type sensors must be monitored, which requires further efforts. 10 15 20 25 30 536 3Û'l Therefore, software-based systems for determining the fuel composition have been developed, which do not use any special fuel type sensors, but evaluate the signals from the sensors available on the internal combustion engine. These systems can be realized more cost-effectively than systems with fuel type sensors.
    DE 3036107 C3 discloses a control arrangement for a fuel supply system of an internal combustion engine consisting of a fuel supply arrangement (fuel injection valve), a lambda probe, means (timing element) for generating a basic supply signal, which depending on the operating condition and control signal (ti), a lambda regulator, which, based on a signal (A) measured by the lambda probe, determines a correction factor, which multiplicatively affects the basic supply signal (tp) by the correction factor. This ensures that the lambda correction in addition to the correction factor (KR A) is dependent on an additive (KA A) and / or a multiplicative (KL A) correction quantity, which is determined depending on the correction factor and operating parameters.
    The control arrangement enables systematic deviations in the fuel supply quantities determined by the basic supply signal, ie the so-called disturbance, to be equalized by the value determined by the lambda control by an adaptation intervention with a proper long-term correction. Systematic deviations may, for example, be due to the onset of aging or manufacturing. On average, the amount of fuel consumed by the corrective disturbance corresponds to the amount actually required.
    The short-term deviation can be evened out with the lambda regulator, which now again has control over the entire control area. The process is also known as blend adaptation.
    The determination of the fuel mixture conditions can take place without additional fuel type sensors based on a fuel adaptation. The fuel adaptation is activated after a refueling identified by the tank level sensor. A change in fuel composition as a result of the refueling process leads to a changed stoichiometric air / fuel ratio. Due to a proper intervention by the Iambda control on the operating parameters of the internal combustion engine, in particular on the set air-fuel ratio and the ignition time, this change in the fuel properties within the framework of the fuel adaptation is taken into account. From the intervention of the lambda regulator and the fuel adaptation, respectively, a conclusion can be drawn regarding the stoichiometric ratio and from this the composition of the fuel mixture. The composition of the fuel mixture can accordingly be determined by a pure software solution in a cost-effective manner.
    A disadvantage here is that after a refueling process, the mixture adaptation must be temporarily deactivated during the fuel adaptation. so that altered combustion properties of the fuel mixture are not incorrectly regulated by the long-term correction of the mixture adaptation. The deactivation of the mixture adaptation is undesirable and is contrary to the requirements of CARB in the USA in particular regarding continuous monitoring and diagnosis of the fuel supply system.
    A further disadvantage of the method is that in a refueling process with small amounts of fuel, the tank level sensors do not always identify this reliably. If such refueling is repeated repeatedly, this can lead, especially at low fuel tank levels, to the fuel composition changing significantly without this being identified and regulated by the fuel adaptation.
    The change in combustion properties is then incorrectly regulated by the mixture adaptation.
    An additional system for determining the fuel mixing ratio without the use of a special fuel type sensor is described in the applicant's document EP1804226 A2. The document describes a method for determining the ratios (z) of the constituents of a fuel mixture, which is fed with a fuel pump, the method being characterized in that a measure (p_KP) of the power consumption of the fuel pump is registered and that with Based on the registered measure (p_KP), the ratio (z) of the constituents of the fuel mixture is determined.
    A further method for determining the fuel mixing ratio without the use of a special fuel type sensor is described in the applicant's document DE102007034189 A1. The specification describes a method for determining the composition of a fuel mixture of a first fuel and a second fuel for operating an internal combustion engine, the first and second fuels having different octane numbers and the internal combustion engine having at least one knock sensor and one knock control. The process is characterized in that the composition of the fuel mixture is determined by means of an output signal from the knock sensor.
    A further method for determining the composition of a fuel mixture of a first and at least a second fuel for operating an internal combustion engine, wherein fuel mixtures of different composition exhibit different knock resistance, is characterized in that the composition of the fuel mixture is determined from the ignition angle, precisely in which no engine knocks occur. The procedure is described in the applicant's document SE532891 C2.
    Applicant's document DE102009028392 A1 describes a method for determining a fuel composition of a fuel mixture of a first and at least a second fuel for operating an internal combustion engine at a known air-fuel ratio or an Iambda value at a known fuel, in which by appropriate interventions the smooth running of the combustion engine is at least periodically adversely affected, the process being characterized in that the actuation is carried out by a variation of an ignition angle and / or by a variation of the air-fuel ratio, whereby from a resulting the uneven running derives a parameter for the composition of the presently present fuel mixture or a lambda value for the cylinder of the internal combustion engine.
    Applicant's document DE102008001668 A1 describes a method for determining the composition of a fuel mixture of a first fuel and at least a second fuel for operating a self-igniting internal combustion engine with at least one sensor which determines the combustion process in at least one cylinder of the internal combustion engine, which that from a quantity which characterizes the combustion process in at least one cylinder of the internal combustion engine a measure of the stability of the combustion process is formed and that the determination of the composition of the fuel mixture takes place from the measure of the stability of the combustion process.
    Applicant's document DE102009028327 A1 describes a method for determining a fuel composition of a fuel mixture of a first and at least a second fuel for operation of an internal combustion engine, wherein a control unit is supplied with an output signal from an in an exhaust duct of the internal combustion engine device. broadband lambda probe, which is characterized in that the composition of the fuel mixture is determined from the course of a pump current characteristic curve of the broadband lambda probe depending on the lambda value of the exhaust gas.
    Said method for determining the composition of a fuel mixture on the basis of various parameters and signals already present in the internal combustion engine and its control unit has the disadvantage that the roughness of estimation which can be achieved in determining the fuel composition is in part considerably greater than the accuracy is required for controlling the internal combustion engine.
    Applicant's SE533647 C2 discloses a method of controlling an internal combustion engine which is driven by a fuel mixture of a first and at least a second fuel, the internal combustion engine having a fuel metering arrangement, a tank level gauge for determining tank contents. and a change in the tank content, a sensor for detecting the cylinder filling for determining an air mass supplied to the internal combustion engine and at least one exhaust probe for determining and regulating the oxygen content in the exhaust, the method being characterized in a first process step - a first value for the composition of the fuel mixture from the supplied air mass and the measured change in the tank content are taken into account, taking into account the oxygen content in the exhaust gas. that in a second process step a second value is determined for the composition of the fuel mixture from the air mass supplied at the idle of the internal combustion engine and the amount of fuel supplied by means of the fuel metering arrangement, that the first and second values are compared with a specified limit deviating values, it is concluded that there is an error in the fuel metering arrangement, in the determination of the supplied air mass or the tank level meter. Accordingly, the method serves to monitor the fuel metering arrangement, monitor the supplied air mass or monitor the tank level gauge; the accuracy in determining the two values for the composition of the fuel mixture is limited to the accuracy of the individual underlying procedures for determining the composition and thus subject to high estimation roughness.
    The task of the invention is to provide a method which enables a reliable and cost-effective distinction of the composition of a fuel mixture of at least two fuels with a sufficiently small roughness of estimation.
    Description of the invention The object of the invention regarding the process is solved by determining from a first parameter a first composition value for the fuel mixture, that from at least a second parameter determining at least a second composition value, that weighting factors for composition values the estimation accuracy of the respective composition value is specified and that the composition of the fuel mixture is determined from a combination of the first composition value and at least the second composition value weighted by the associated weighting factors.
    Due to the different properties of the pure fuels, different chemical and physical properties result as well as different combustion properties for fuel mixtures composed in different mixing ratios. These properties affect the parameters, which are mostly independent of each other, which are registered for controlling the internal combustion engine. Accordingly, indications for the composition of the fuel mixture in the form of composition values can be deduced from the individual parameters. A composition value describes the composition of the fuel mixture. as determined by a parameter. The individual composition values, depending on the correlation of the underlying parameters with the composition of the fuel mixture and tolerances in the determination of the underlying measurement values, exhibit estimation roughnesses, which can be significantly greater than the desired accuracy in determining the composition of the fuel mixture. . Since the individual parameters are independent of each other, a stochastic distribution of the composition values derived therefrom and the associated roughness of estimates can be assumed. Through an appropriate combination of the individual composition values, the actual composition of the fuel mixture can therefore be determined significantly more accurately than is possible on the basis of the individual composition values. Thus, an increased number of available composition values increases the estimation accuracy.
    The composition values can be derived from sensor signals or from calculation values in a program sequence of a control of the internal combustion engine. Therefore, different composition values can be determined with different accuracy.
    According to the invention, care is therefore taken to ensure that the composition values in determining the composition of the fuel mixture are provided with weighting factors which reflect the respective estimation accuracies.
    This reduces the deviation of the determined composition from the real value. Furthermore, the size of the expected average deviation can be determined more accurately.
    An advantage of the method is that the determination of the composition values and consequently the composition of the fuel mixture can also take place at the already existing parameters of modern internal combustion engines. No additional components, such as additional fuel type sensors, need to be provided, enabling a cost-effective implementation of the process as a pure software solution.
    In order to carry out the inventive procedure, it is not necessary to deactivate diagnostic functions prescribed by legislators, such as mixture adaptation, whereby the acceptance of the procedure in comparison with pre-existing software solutions is significantly increased.
    An additional advantage relative to possible solutions is that the determination of the fuel composition is not bound to the identification of a refueling process. If, in pre-existing processes, which require the identification of a refueling process, numerous small amounts of the tank level sensor system are not refueled, this can - especially at a small filling level in the tank - lead to a significant change in the composition of the fuel mixture. In different operating ranges of the internal combustion engine such as idling, engine braking, partial and full load operation, the composition values can be determined with varying accuracy. According to the invention, care is therefore taken to ensure that the folding factors for the individual composition values are specified depending on the prevailing operating range of the internal combustion engine. In this case, it can also be ensured that in an operating area a weighting factor for a composition value is zero and that this composition value is not taken into account when determining the composition. In this embodiment, the composition of the fuel mixture can be determined with improved accuracy in a wider area of use of the internal combustion engine.
    If the weighting factors are determined from the inverted value of the percentage estimation accuracy of the composition value, the Gaussian error propagation of the most probable composition of the fuel mixture and the average deviation from the fair value can be calculated by the method. For example, if the estimation accuracy is 20%, the weighting factor 110.2 = 5 should be used. In a case with two composition values Z1 and Z2 and two weighting factors W1 and W2, the most probable composition is wZ wz = (w12'z1 + w22 * z2) / (w12 + w2 =).
    The accuracy m of the most probable composition wZ for a maximum ethanol content of 85% is calculated to m = as% / Jw12 + w22 The composition of a fuel mixture can be determined from a specified number of composition values, by determining the composition of the fuel mixture from the sum of the composition values multiplied by the square of the associated weighting factors divided by the sum of the square of the weighting factors. According to this calculation according to the method of Gaussian reproduction, the most probable value of the composition is determined. An increase in the number of composition values advantageously reduces the deviation from the fair value of the composition and improves the margins of error in the determination. 10 15 20 25 30 536 301 11 A particularly simple specification of the weighting factors for different operating areas and a simple calculation with sufficient accuracy can be achieved by specifying the weighting factors in steps.
    The accuracy that can be achieved with the estimation care for the true composition can be calculated by dividing the maximum ethanol content by the square root from the sum of the squared weighting factors. fi d an ethanol content of a maximum of 85% and a relative average deviation of 10%, the absolute average deviation consequently amounts to 8.5%.
    Modem internal combustion engines often have knock sensors, the output of which is used for a knock control. If fuels differ in octane number and knock resistance, respectively, the octane number and knock resistance of a fuel mixture obtained therefrom are determined by the mixing ratio of the fuels involved. From the knock sensor output signal or a control sequence of the knock control, for example ignition angle output, conclusions can thus be drawn regarding the composition of the fuel mixture independently of an additional method for determining composition values. Thus, it can be provided that one of the parameters for determining one of the composition values of the fuel mixture is determined from an output signal from a knock sensor or from a knock control of the internal combustion engine and that depending on the achieved estimation accuracy of the specification value. . Depending on the number of different operating areas, a number of weighting factors for the thus determined composition value can be specified.
    An additional composition value can be determined by using the speed of an electronically commutating fuel pump or the electric current supplied to the fuel pump as parameters for determining one of the composition values of the fuel mixture and, depending on the estimated accuracy of the achieved accuracy. 10 15 20 25 30 536 30 '| 12 the composition value specifies at least one weighting factor for the composition value. Physical characteristics that distinguish the blended fuels are the different viscosity and the different temperature dependence of the viscosity of the individual fuels and thus the resulting fuel mixture. The viscosity of the fuel mixture directly affects the speed and the electric current supplied to the fuel pump, so indications concerning the composition of the fuel mixture can be obtained from these parameters. An advantage here is that the determination of the composition value takes place independently of other methods for determining parameters from which additional composition values are derived, which constitutes a prerequisite for a stochastic distribution of the composition values.
    According to a preferred embodiment variant of the invention, it may be provided that one of the parameters for determining one of the composition values of the fuel mixture is determined by lowering a feed pressure generated by a low-pressure fuel pump so low that steam bubbles appear in the area between the pump pressure and the , which is used as a parameter for the feed pressure, from which steam bubbles arise and depending on the achieved estimation accuracy of the composition value thus determined, at least one weighting factor for the composition value is predetermined. The method can be used in particular with direct-injection internal combustion engines. This is based on the different vapor pressures of the fuels used. For example, a fuel mixture of ethanol and petrol at a constant temperature and an ethanol content exceeding 30% shows a decreasing vapor pressure with increasing ethanol content. If, for example, during a test function, the supply pressure of the low-pressure fuel pump is temporarily lowered so low that due to the underside of the fuel mixture's vapor pressure vapors form in the fuel mixture between the low-pressure fuel pump and the high-pressure fuel supply pump. At a known temperature, a conclusion can now be drawn from the set night pressure regarding the composition of the fuel mixture. 10 15 20 25 30 536 301 13 Fuels differ in terms of their energy density. Accordingly, the energy density of a fuel depends on the mixing ratio and the respective energy densities of the fuels used. The power requirement of an internal combustion engine at idle is known and can be determined depending on the coolant temperature, efficiency, ignition angle and side consumers such as air conditioning compressor, generator, coolant pump, oil pump and speed. In the case of a fuel with a low energy density, in comparison with a fuel with a high energy density, the combustion engine must be supplied with more fuel at idle. The amount of fuel supplied to the internal combustion engine at idle is therefore directly related to the mixing ratio of the fuel mixture and can be used as a parameter for determining a composition value. Thus, it can be ensured that as a parameter for determining one of the composition values for the fuel mixture, the consumption of the fuel mixture at idle is used and that depending on the achieved estimation accuracy of the thus determined composition value, at least one weighting factor is specified for the composition value. It is advantageous in this case that the combustion engine supplied with fuel at idle speed is used as a parameter via the injection device's injection time.
    A leaner air-fuel mixture, ie an increasing lambda value, leads to an increasingly uneven running in internal combustion engines. Different fuels and fuel mixtures composed therefrom have a typical so-called lean limit and furthermore a limit for the amount of exhaust gas recyclable in an exhaust gas recirculation. If the air-fuel mixture supplied to the internal combustion engine is made leaner, the ignition delay increases and the ignition becomes slower or is not initiated at all. This leads to extremely lagging combustion or to interruption of combustion, which in turn results in a markedly increased uneven running.
    Knowledge of the lean limit and the limit for exhaust gas recirculation is an indication of the mixing ratio of the fuel mixture used.
    Therefore, it may be provided that as a parameter for the determination of one of the composition values of the fuel mixture a lean limit 10 or 20 25 30 536 301 14 and / or a limit for the exhaust gas return tolerance limit is used and that depending on the estimated accuracy of the composition value thus determined. at least one weighting factor for the composition value. It is advantageous here that the lean limit and the exhaust gas return tolerance limit can be easily determined by a proper variation of the air-fuel ratio or the amount of exhaust gas returned. An altered combustion stochastic theory can be determined by evaluating the crankshaft speed, for example by suitable smooth running algorithms.
    It is provided that as a parameter for determining one of the composition values of the fuel mixture the course of a pump current of a broadband lambda probe arranged in the exhaust gas from the internal combustion engine is used and that depending on the estimated accuracy of the så weighting factor for the composition value, then for determining the composition of the fuel mixture from a further independently determined composition value can be resorted to. Exhaust gases from various fuels. for example from ethanol and petrol, are characterized by different hydrogen-carbon monoxide ratios. The exhaust gas from ethanol in an ethanol-containing fuel mixture then shows a greater hydrogen-carbon monoxide ratio than that which results from the combustion of pure petrol. Due to the changed gas mixture, the characteristic curve of the broadband lambda probe, in particular in an area lambda <1, shows a pump current behavior dependent on the mixing ratio of the fuel used. It is advantageous here that for determining the composition value, an existing broadband lambda probe can be gripped and no additional components are required, so that only a proper software adaptation in the internal combustion engine control device is necessary.
    Without further components, a composition value can be determined by deriving one of the parameters for determining one of the composition values of the fuel mixture from a thickness of an intake 10 15 20 25 30 536 30 '| 15 pipe wall fi lm and that depending on the achieved estimation accuracy of the composition value thus determined, at least one weighting factor for the composition value can be specified. In internal combustion engines with intake manifold injection, an intake manifold wall is formed by the prevailing fuel and by the prevailing fuel mixture, respectively. The thickness of the intake manifold wall depends on the evaporation enthalpy of the fuel used. Since fuels, such as petrol and ethanol, differ in terms of evaporation enthalpy, the intake pipe wall thickness is directly dependent on the fuel used. In the event of a change in the air-fuel ratio caused by a driver's wish or engine control, the intake manifold wall fi l- must first be built up or thinned to the new equilibrium thickness. The composition value can therefore be determined by observing the lambda action during the transition from a fuel throttle during engine braking to the reintroduction of fuel supply and combustion.
    According to a further design of the invention, it is provided that one of the parameters for determining one of the composition values for the fuel mixture is determined from the regulation of the mixture adaptation and that depending on the achieved accuracy of the composition value thus determined, a weighting factor is specified.
    The combustion properties of fuel mixtures are directly dependent on the prevailing composition of the fuel mixture. Through the lambda-controlled mixture adaptation, the operating parameters of the combustion engine are adjusted in the event of a changed fuel composition in the direction so that the exhaust composition is in the specified range, for example at lambda = 1. From the passive observation of the mixture adaptation, ie without an intervention a blocking of the mixture adaptation in a fuel supply diagnosis, an additional indication concerning the composition of the fuel mixture and consequently an additional composition value can be obtained. 10 15 20 25 30 536 301 16 An additional composition value for the fuel mixture can be independently determined by using a signal from a fuel type sensor as a parameter for determining one of the composition values for the fuel mixture and, depending on the estimated accuracy of the composition value thus determined. specify at least one weighting factor for the composition value.
    The task of the invention concerning the device is solved by supplying parameters and / or signals for determining the parameters to the control unit, that a program sequence is provided in the control unit for determining at least two composition values from the parameters, that weighting factors depend on the the specific operating areas are specified and that a program sequence is provided in the control unit for determining the composition of the fuel mixture from the at least two composition values and the associated weighting factors. The composition of a fuel mixture can consequently be determined by a pure software solution without additional components, without the diagnostic functions prescribed by the legislator having to be temporarily deactivated. The number of composition values taken into account for determining the composition of the fuel mixture can be expanded corresponding to the number of signals and parameters present in the control unit, which depend on the properties of the fuel mixture, whereby the roughness of the determined composition of the fuel mixture can be reduced.
    The method and apparatus can preferably be used to determine the composition of a fuel mixture of gasoline and alcohol, preferably a fuel mixture of gasoline and ethanol.
    Brief description of the drawings The invention is explained below on the basis of an exemplary embodiment illustrated in the figure. There: 10 15 20 25 30 536 301 17 Figure 1 shows a diagram for the determination of a composition of a fuel mixture.
    Figure 1 shows a diagram for the determination of a composition 10 of a fuel mixture of fl are parameters characteristic of the composition 10, for example a petrol-ethanol-fuel mixture. Along a first axis 11, the percentage of ethanol in the fuel mixture is introduced. In order to achieve a desired total deviation 16 in the determination, a first composition value 12, a second composition value 13, a third composition value 14 and a samm fourth composition value 15 are determined from the parameters characteristic of the composition 10. 14, 15 are shown as expected values with standard deviation and are arranged next to each other along a second axis 17. The composition values 12, 13, 14, 15 can be determined as characterizing parameters from, for example, an octane number, a vapor pressure of the fuel mixture, a lean limit or a knock resistance. Instead of four values, according to the invention, a number other than two or more than two composition values can also be used.
    The standard deviation of the composition values 12, 13, 14, 15 can then be greater than the desired maximum total deviation 16 for determining the composition 10 of the fuel mixture.
    According to the invention, the composition 10 of the fuel mixture is determined by a combination of the composition values 12, 13, 14, 15. The combination takes place by forming a weighted average value of the composition values 12, 13, 14, 15. The composition values 12, 13, 14, 15 are coordinated with weighting factors 18, which are a measure of the estimation accuracy of the respective composition value 12, 13, 14, 15.
    For example, a weighting factor 18 with the value 5 expresses an estimation accuracy of 1/5 = 20%; a weighting factor 18 with the value 4 means an estimation accuracy of 1/4 = 25%. Since the composition values 12, 13, 14, 15 are determined independently of each other and consequently it can be assumed from a stochastic distribution of the composition values 12, 13, 14, 15 around the composition 10, the required and through the total deviation 16 the accuracy in determining the composition 10 of the fuel mixture is achieved, even when estimating roughnesses of the underlying composition values 12, 13, 14, 15 are significantly greater.
    With an increasing number of composition values 12, 13, 14, 15 to consider, the weighted average formed approaches the actual composition 10 and thus the true alcohol content of the fuel mixture and the error in determining the composition 10 is reduced.
    The improvement of the estimation accuracy by using the weighted average value is explained below by a calculation example: The first composition value 12 amounts to 40%, the first composition value 13 amounts to 20%. The weighting factors 18, which represent the measurement deviation in the determination of the respective parameter, amount to 5 and 3, respectively. s2 + zowaz) / (52 + 32) = 34.7% Similarly, according to the method of Gaussian error assessment, the accuracy of the determination of the composition 10 at the two weighting factors 18 with the values 5 and 3 and a maximum ethanol content of 85% can be determined: 85% / / 52 + 32 = 14.6% The combination of the two composition values 12, 13 with weighting factors 18 with values 5 and 3. which correspond to accuracies of 85% l5 = 10 15 20 536 301 19 17% and 85% / 3 respectively = 28.3%, consequently gives an estimate with an improved accuracy of 14.6%.
    For an arbitrary number of n composition values Zi with weighting factors W1, the ethanol content and the achievable accuracy at a maximum ethanol content Emax can be calculated as follows: L: Wiz * Zi ethanol content = 2:21 WP accuracy = According to the invention, the weighting factors 18 can be determined depending on the condition. This improves the reliability and accuracy of the process, as parameters can be determined particularly accurately and are therefore heavily weighted in certain operating conditions. It can also be ensured that a parameter in a certain operating condition is weighted with the factor "zero" and consequently not taken into account.
    Since the individual composition values 12, 13, 14, 15 can be determined by a control unit of the internal combustion engine already before parameters and sensor signals, the composition 10 of the fuel mixture can be determined by a pure software solution in the control unit, without additional components and sensors having to be provided. . To determine the composition values 12, 13, 14, 15 and the composition 10, no diagnostic routines, for example the mixture adaptation, need be interrupted.
    权利要求:
    Claims (16)
    [1]
    1. 0 15 20 25 30 536 301 20 Claim 1.
    [2]
    A method for determining the composition (10) of a fuel mixture of a first fuel and at least a second fuel in a control unit associated with an internal combustion engine for operating the internal combustion engine, the fuels differing in their chemical and / or physical and / or combustion properties, the operating ranges of the internal combustion engine being defined from each other and parameters being determined for controlling the internal combustion engine, which parameters are dependent on the chemical and / or physical and / or combustion properties of the fuel mixture, from a first parameter already present in the control unit, a first composition value (12) for the fuel mixture is determined, that from at least one second parameter already present in the control unit, which is independent of the first parameter, it is determined, independent of the first composition value (12), at least a second composition value (13) for the fuel mixture, that weighting factors (18) for the composition values (12, 13) depending on the estimation accuracy of each composition value are specified and that the composition (10) of the fuel mixture is determined from a combination of the first composition value (12) weighted by the associated weighting factors (18) and at least the second composition value (13) by means of an extended software, the weighting factors (18) for the individual composition values (12, 13) being specified depending on the prevailing operating range of the internal combustion engine.
    [3]
    Method according to Claim 1, characterized in that the weighting factors (18) are determined from the inverted value of the percentage estimation accuracy of the composition value.
    [4]
    Method according to one of Claims 1 or 2, characterized in that the composition (10) of the fuel mixture is determined from the sum of the composition values (12, 13) multiplied by the square of the associated weighting factors (18). ) divided by the sum of the squares of the weighting factors (18). Method according to one of Claims 1 to 3, characterized in that the weighting factors (18) are specified in steps. .
    [5]
    Method according to one of Claims 1 to 4, characterized in that the achievable accuracy of the estimated value of the true composition is calculated by dividing the maximum ethanol content by the square root from the sum of the squared estimation accuracies divided by the square of the number considered. composition values. .
    [6]
    Method according to one of Claims 1 to 5, characterized in that one of the parameters for determining one of the composition values (12, 13, 14, 15) of the fuel mixture is determined from an output signal from a knock sensor or from a knock control of the internal combustion engine, and that depending on the achieved estimation accuracy of the composition value thus determined, at least one weighting factor (18) is specified for the composition value (12, 13, 14, 15). .
    [7]
    Method according to one of Claims 1 to 6, characterized in that the speed of an electronically commutating fuel pump or the electric supplied to the fuel pump is used as parameters for determining one of the composition values (12, 13, 14, 15) of the fuel mixture. the current and that depending on the achieved estimation accuracy of the composition value thus determined, at least one weighting factor (18) is specified for the composition value (12, 13, 14, 15). .
    [8]
    Method according to one of Claims 1 to 7, characterized in that one of the parameters for determining one of the composition values (12, 13, 14, 15) of the fuel mixture is determined in that one of a number of 536 301 22 low-pressure fuel pump generated supply pressure is lowered so low that in the area between the low-pressure fuel pump and a subsequently arranged high-pressure fuel pump steam bubbles are formed, which are used as parameters for the pre-supply pressure, from which steam bubbles occur and depending on the achieved achieved at least one weighting factor (18) is specified for the composition value (12, 13, 14, 15).
    [9]
    Method according to one of Claims 1 to 8, characterized in that the consumption of fuel mixture at idle is used as a parameter for determining one of the composition values (12, 13, 14, 15) and that, depending on the estimated estimation accuracy of the composition value thus determined specifies at least one weighting factor (18) for the composition value (12, 13, 14, 15).
    [10]
    Method according to one of Claims 1 to 9, characterized in that a lean limit and / or a limit for the exhaust gas return tolerance is used as the parameter for determining one of the composition values (12, 13, 14, 15) of the fuel mixture and that Depending on the achieved estimation accuracy of the composition value thus determined, at least one weighting factor (18) is specified for the composition value (12, 13, 14, 15).
    [11]
    Method according to one of Claims 1 to 10, characterized in that, as a parameter for determining one of the composition values (12, 13, 14, 15) of the fuel mixture, the course of a pump current of a broadband lambda probe arranged in the combustion engine exhaust gas is used depending on the lambda value of the exhaust gas. and that depending on the achieved estimation accuracy of the composition value thus determined, at least one weighting factor (18) is specified for the composition value (12, 13, 14, 15). 10 15 20 25 30 535 301 23
    [12]
    Method according to one of Claims 1 to 11, characterized in that one of the parameters for determining one of the composition values (12, 13, 14, 15) of the fuel mixture is derived from a thickness of an intake manifold wall film and that, depending on the estimation accuracy obtained, of the composition value thus determined, at least one weighting factor (18) specifies the composition value (12, 13, 14, 15).
    [13]
    Method according to one of Claims 1 to 12, characterized in that one of the parameters for determining one of the composition values (12, 13, 14, 15) of the fuel mixture is determined from the control of the mixture adoption and that, depending on the estimation accuracy achieved by the determined composition value, at least one weighting factor (18) is specified for the composition value (12, 13, 14, 15).
    [14]
    Method according to one of Claims 1 to 13, characterized in that a signal from an ethanol sensor is used as the parameter for determining one of the composition values (12, 13, 14, 15) and that, depending on the estimation accuracy achieved at the so-called determined composition value, at least one weighting factor (18) is specified for the composition value (12, 13, 14, 15).
    [15]
    Device for determining the composition (10) of a fuel mixture of a first fuel and at least a second fuel for the operation of an internal combustion engine, the fuels differing in their chemical and / or physical and / or combustion properties, wherein operating ranges of the internal combustion engine is delimited from each other, parameters for controlling the internal combustion engine being determined, which depend on the chemical and / or physical and / or combustion properties of the fuel mixture and wherein the internal combustion engine is associated with a control unit, characterized in that in the control unit other independent parameters, that a program sequence is provided in the control unit for independently determining at least two composition values (12, 13, 14, 15) from the independent parameters, that weighting factors (18) depend on the estimation accuracy of the composition. the employment values for each operating area are specified and that a program sequence is provided in the control unit for determining the composition of the fuel mixture from the at least two composition values and the associated weighting factors (18).
    [16]
    Use of the method or device according to any one of the preceding claims for determining the composition (10) of a fuel mixture of petrol and alcohol, preferably a fuel mixture of petrol and ethanol.
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE102009029012|2009-08-31|
    DE102009045419A|DE102009045419A1|2009-10-07|2009-10-07|Determining composition of fuel mixture, e.g. gasoline and ethanol, involves combining weighting factor with composition values derived from engine parameters|
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