• 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 fuel mixture of a first fuel and a second fuel for operation of an internal combustion engine with at least one cylinder pressure sensor for determining the cylinder pressure in at least one cylinder in the internal combustion engine. the calorific value of the fuel mixture or a parameter correlating with the calorific value is determined and the composition of the fuel mixture is determined from the calorific value or the parameter correlating with the calorific value. The invention further relates to a device for carrying out the method. Method and device enables a fast and reliable detection of the composition of a fuel mixture from the values measured by the cylinder pressure sensors.
    公开号:SE1251271A1
    申请号:SE1251271
    申请日:2012-11-09
    公开日:2013-05-12
    发明作者:Ralf Daeubel；Michael Haufer
    申请人:Bosch Gmbh Robert；
    IPC主号:
    专利说明:

    _2_ parts by weight of air per proportion of petrol, when using ethanol an air proportion of 9 parts by weight must be set. In addition, it is known that by means of a so-called mixing adaptation, based on the signal from a lambda or oxygen probe in the exhaust system of the internal combustion engine, to detect a corresponding adaptation or correction value and thereby adapt the air / fuel ratio to the fuel composition.
    However, this requires a very large setting range for mixing adjustment. For lambda displacements, due to tolerances in the fuel path (fuel pressure error, flow error of injection valves) or in the airway (air mass error due to tolerances of the hot film air mass meter VFM or from pressure sensors) then often only limited correction options are available.
    Due to the different combustion conditions of ethanol and petrol, the need also arises to carry out a control of the ignition of the internal combustion engine, depending on the ethanol content of the fuel mixture.
    It is already known to determine with separate sensors the composition of the fuel mixture, and consequently to consider it in the engine control.
    In addition, different types of fuel type sensors are used, which are also called "fuel composition sensors". The fuel type sensors use the different properties of alcohol and gasoline to determine the fuel composition. For example, ethanol is a protic solvent that contains hydrogen gases and has a high dielectric constant, which, however, depends on the water content. Gasoline, on the other hand, is an aprotic solvent with a small dielectric constant. Based on this, there are fuel type sensors, which determine the fuel composition with the help of the dielectric properties of the fuel mixture. Other types of fuel type sensors use the different optical properties of the fuel, for example different refractive indices. The use of additional sensors is associated with increased costs.
    To optimize the ignition, alternative methods are known, where thermodynamic auxiliary quantities formed with the aid of the signals from cylinder pressure sensors are adjusted _3_ to predetermined setpoints. Thereby, the ignition can be set to an optimal value without explicit knowledge of the composition of the fuel mixture.
    From the document DE 10 2007 060 223 A1 a method is known for determining a composition of a fuel mixture of a first fuel and a second fuel or for determining the quality of a fuel for operating an internal combustion engine with at least one cylinder pressure sensor in at least one cylinder of the internal combustion engine for determining the pressure profile during a combustion process, and a cylinder pressure-based engine control for regulating the load and the combustion state of the internal combustion engine. Thus, it is arranged that the determination of the composition of the fuel mixture, or the quality of the fuel, is carried out by means of control information of the cylinder pressure-based engine control. It is proposed that the determination of the composition of the fuel mixture or the quality of the fuel is carried out by parameter correction and / or control deviations in the cylinder pressure-based engine control.
    From DE 10 2007 023 900 A1 a method for determining the composition of a fuel mixture of a first fuel and a second fuel for driving an internal combustion engine is known, the first and the second fuel having different combustion rates, and / or has different specific energy contents, and wherein the combustion engine has at least one pressure sensor in at least one combustion chamber, with which a time and / or angular synchronous pressure course in the combustion chamber is determined.
    Thus, it is arranged that the composition of the fuel mixture from the time and / or angular synchronous pressure profile of the gas pressure in the at least one combustion chamber is determined during a combustion phase.
    It is an object of the invention to provide a method which enables a reliable and cost-effective detection of the composition of a fuel mixture of at least two fuels. It is a further object of the invention to provide an apparatus for carrying out the method.
    Description of the invention The object of the process according to the invention is achieved by determining from the cylinder pressure the calorific value of the fuel mixture or a parameter correlating with the calorific value and from determining the composition of the fuel mixture from the calorific value or the correlating parameter.
    This presupposes that the calorific value of the first fuel and the second fuel differs, as is the case, for example, with a petrol-ethanol mixture. The calorific value for petrol is 42.8 MJ / kg, and for ethanol at 26.8 MJ / kg.
    For each mixing ratio between the first and the second fuel, an associated calorific value is obtained. If this relationship is known, at known calorific values of a present fuel mixture, the unique composition can be unambiguously determined. As the calorific value is determined from the actual course of the cylinder pressure, it corresponds to the actual injected fuel mixture. A change in the fuel mixture is therefore detected in a few operating cycles of the internal combustion engine. Thus, necessary corrections to control the engine can be performed quickly and on the correct grounds. If the internal combustion engine already has a cylinder pressure sensor for other control tasks, then no additional components are needed to perform the procedure, it can be carried out in a correspondingly inexpensive manner. Expensive fuel type sensors, for example in the form of an ethanol sensor, can be saved. According to a particularly preferred embodiment of the invention, it is arranged that from the course of the cylinder pressure the average indicated cylinder pressure pmi is determined, that from the average indicated cylinder pressure pm; the average indicated work Wi is determined, that from the average indicated work Wi and an amount of fuel injected in the current work cycle, the calorific value or the parameter correlating with the calorific value is determined and from there the composition of the fuel mixture is determined. The average indicated cylinder pressure pm, is calculated as an average value over the measured cylinder pressure during a working stroke, minus the average value of the measured cylinder pressure in a compression stroke. It can be easily determined from the signal from the cylinder pressure sensor, for example with a control unit which is arranged to the internal combustion engine. _5_ The average indicated cylinder pressure pmi is directly dependent on the energy released during combustion, so that the average indicated work W; can be determined at a known Cylinder volume. The calorific value is obtained from the ratio of the average indicated work Wi and the amount of fuel injected into the work cycle.
    Via the unambiguous relationship between the composition of the fuel mixture and its calorific value, the fuel ratio in the fuel mixture can be determined.
    The accuracy of the determination of the composition of the fuel mixture can be improved by performing an averaging over different cylinders and / or a plurality of duty cycles when determining the calorific value or the parameter correlated with the calorific value. The averaging can then be carried out, for example, on successively determined calorific values or average indicated cylinder pressures pm; or indicated works Wi.
    For averaging over different cylinders, corresponding cylinder pressure sensors are required in the respective cylinders.
    To avoid incorrect calorific value results, the conditions for this should be followed.
    In addition, it can be arranged that the determination of the composition of the fuel mixture is carried out in accordance with a check of fault conditions with regard to pressure in the fuel system and / or sufficiently long opening times for the injection valve and / or the combustion process. By checking the pressure in the fuel system, faults in the fuel system can be detected. Sufficiently long opening times of the injection valve minimize fault tolerances of the injection valve. A valid combustion process can, for example, be monitored via the position of the combustion center of gravity and the height of the peak pressure.
    When determining the calorific value and thus the composition of the fuel mixture, the amount of fuel injected is necessary. In order to improve the accuracy of the controlled fuel mass calculation of the injection time, it can be arranged so that the determined calorific value and / or the parameter correlating with the determined calorific value and / or the composition of the fuel mixture are reconnected and taken into account in the calculation of the injected fuel quantity _ _6_ For optimization and validation of the result, it may be arranged so that the determined calorific value or the determined, with the calorific value correlating parameter, is checked with respect to the exceeding of a theoretical maximum value, or to the undercutting of a theoretical minimum value. As a result, the tolerances can be further limited. In the event of a fall below the minimum value, in collaboration with a combustion process analysis when using pure ethanol as fuel, an excessively high water content can also be determined. The object of the device according to the invention is achieved by the control unit providing a circuit device or a program sequence for determining the calorific value of the fuel mixture as a ratio between the indicated work Wi and the injected fuel quantity, that the control unit has information stored between the calorific value and the composition of the fuel mixture. that a control sequence for determining the composition of the fuel mixture from the determined calorific value is provided in the control unit and the information is provided for the relationship between the calorific value and the composition of the fuel mixture. The information about the relationship between the calorific value and the composition of the fuel mixture can be stored, for example, in the form of a calculation instruction or a table with values. The calculation of the calorific value is thus carried out based on the information already present in the control unit of the internal combustion engines which are equipped with cylinder pressure SGFISOFGF.
    The method and apparatus can preferably be used to determine the composition of a fuel mixture of gasoline and ethanol.
    The invention is shown below with reference to an exemplary embodiment which is shown in more detail in the figures. It shows: Figure 1 shows a diagram of the relationship between the calorific value and the ethanol content of fuel mixtures of petrol and ethanol, Figure 7 shows a block diagram of the course of the determination of the composition of a fuel mixture of two fuels.
    Figure 1 shows a diagram of the relationship between calorific value 11 and the ethanol content in fuel mixtures of petrol and ethanol. There, the calorific value 11 is shown relative to an axis with the calorific value 10 in MJ / kg and an axis showing the ethanol content 12 as a percentage.
    Pure petrol has a calorific value 11 of 42.8 MJ / kg, pure ethanol of 26.8 MJ / kg. In between, the relationship runs linearly via the mixing ratio. If the calorific value 11 of the fuel mixture is known, the ethanol content and thus the composition of the fuel mixture can be determined directly. For example, a calorific value 11 of 40.4 MJ / kg results in an ethanol content of 15% in the fuel mixture.
    Figure 2 shows a block diagram for the course of the determination of the composition of a fuel mixture of petrol and ethanol, as it can be carried out in a control device for an internal combustion engine.
    A first block 20 is supplied with an output signal with a cylinder pressure from a cylinder pressure sensor. The cylinder pressure 40 is measured in a cylinder in an internal combustion engine (not shown).
    In the first block 20, from the course of the cylinder pressure 40 according to known methods, an indicated work Wi is determined, since it has been converted from the actual injected fuel into the cylinder. The indicated work W, is added to a division point 31.
    In a second block 21 there is an effective injection time, which indicates how long the fuel mixture has been injected efficiently into the cylinder in the current working cycle.
    From there, a multiplication point 30 determines an injection amount stored in a third block 22. The injection amount is the amount of fuel supplied to the cylinder in the current duty cycle. It is added to division point 31.
    In the division point 31, by dividing the indicated work W, and the injection mass, the calorific value 11 is saved in the fourth block 23. The calorific value 11 is determined in a comparison point 32 via the relationship between calorific value 10 and the mixing ratio 12 shown in Figure 1. of the fuel mixture the ethanol content in the present petrol - ethanol mixture and is stored in a fifth block 24. The composition of the fuel mixture is thus known and can be taken into account when controlling the internal combustion engine.
    The composition of the fuel mixture is added to a sixth block 25, and it is taken into account there in determining a medium correction factor. From the medium correction factor and the effective injection time te the injection amount is determined in the multiplication point 30. Alternatively or in addition, the calorific value 10 stored in the block 23 can also be taken into account in determining the medium correction factor and thus be fed back to improve the accuracy of the disturbed fuel mass calculation.
    权利要求:
    Claims (1)
    [1]
    A method for determining the composition of a fuel mixture of a first fuel and a second fuel for operating an internal combustion engine with at least one cylinder pressure sensor for determining the cylinder pressure (40) in at least one cylinder of the internal combustion engine, characterized that the calorific value (11) of the fuel mixture or a parameter that correlates with the calorific value (11) is determined from the cylinder pressure (40) and that the composition of the fuel mixture is determined from the calorific value (11) or the correlated parameter. Method according to claim 1, characterized in that from the course of the cylinder pressure (40) the average indicated cylinder pressure pmi is determined, that from the average indicated cylinder pressure pmi the average indicated work Wi is determined, that from the average indicated work Wi and the injection in each work cycle the amount of fuel is determined by the calorific value (11) of the fuel mixture or a parameter that correlates with the calorific value (11) and hence the composition of the amount of fuel. Method according to Claim 1 or 2, characterized in that when determining the calorific value (11) or the parameter correlating with the calorific value (11), an average value formation follows over different cylinders and / or several duty cycles. Method according to one of Claims 1 to 3, characterized in that the determination of the composition of the fuel mixture takes place according to a check of the fault condition with respect to pressure in the fuel system and / or a sufficiently long opening time of the injection valve and / or the combustion process. Method according to one of Claims 1 to 4, characterized in that the determined calorific value (11) and / or the parameter correlating with the determined calorific value (11) and / or the composition of the fuel mixture are reconnected and taken into account when calculating the amount of fuel injected. . A method according to any one of claims 1 to 5, characterized in that the determined calorific value or the parameter correlating with the calorific value (11) is checked for exceeding a theoretical maximum value, or for falling below a theoretical minimum value. Apparatus for determining the composition of a fuel mixture of a first fuel and a second fuel for the operation of an internal combustion engine, the internal combustion engine having at least one cylinder pressure sensor for determining the cylinder pressure (40) in at least one cylinder of the internal combustion engine, with a control unit for controlling the internal combustion engine, to determine an indicated mean pressure pmi, and an indicated work Wi during the high pressure loop in a working cycle from the signals from the cylinder pressure sensor and to determine the amount of fuel injected, characterized in that the control unit provides a circuit device or program sequence to determine (11) of the fuel mixture as the ratio of the indicated work Wi and the amount of fuel injected, that in the control unit information is stored regarding the relationship between the calorific value (11) and the composition of the fuel mixture and that a control sequence is provided in the control unit to determine of the composition of the fuel mixture from the determined calorific value (1 1) and the information on the relationship between the calorific value (11) and the composition of the fuel mixture. Use of a method and the device according to any one of the preceding claims for determining the composition of 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
    JPH0750099B2|1987-09-29|1995-05-31|三菱電機株式会社|Fuel property detection device for internal combustion engine|
    DE102007023900A1|2007-05-23|2008-11-27|Robert Bosch Gmbh|Method for determining a fuel composition|
    DE102007060223A1|2007-12-14|2009-06-18|Robert Bosch Gmbh|Method for determining the composition and quality of a fuel mixture for operating a combustion engine comprises using control information from an engine control unit based on cylinder pressure|
    DE102008001668A1|2008-05-08|2009-11-12|Robert Bosch Gmbh|Method and device for determining the composition of a fuel mixture|
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    GB2474512B|2009-10-19|2013-08-28|Gm Global Tech Operations Inc|Method for biodiesel blending detection based on internal mean effective pressure evaluation|DE102012020137B4|2012-10-15|2019-04-11|Mtu Friedrichshafen Gmbh|Method for operating a reciprocating internal combustion engine|
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    法律状态:
    2017-01-31| NAV| Patent application has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    DE102011086146A|DE102011086146A1|2011-11-11|2011-11-11|Method and device for determining the composition of a fuel mixture|
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