WO2011101962A1 - Fuel property determination device for internal combustion engine - Google Patents

Fuel property determination device for internal combustion engine Download PDF

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Publication number
WO2011101962A1
WO2011101962A1 PCT/JP2010/052365 JP2010052365W WO2011101962A1 WO 2011101962 A1 WO2011101962 A1 WO 2011101962A1 JP 2010052365 W JP2010052365 W JP 2010052365W WO 2011101962 A1 WO2011101962 A1 WO 2011101962A1
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Prior art keywords
fuel
dielectric constant
internal combustion
combustion engine
temperature
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PCT/JP2010/052365
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French (fr)
Japanese (ja)
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美江 笹井
和弘 若尾
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トヨタ自動車株式会社
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Priority to PCT/JP2010/052365 priority Critical patent/WO2011101962A1/en
Publication of WO2011101962A1 publication Critical patent/WO2011101962A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
    • G01N27/221—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance by investigating the dielectric properties
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/26—Oils; Viscous liquids; Paints; Inks
    • G01N33/28—Oils, i.e. hydrocarbon liquids
    • G01N33/2829—Mixtures of fuels

Definitions

  • the present invention relates to a fuel property determination device for an internal combustion engine.
  • Japanese Patent Laid-Open No. 5-240853 discloses a device for detecting the specific gravity of a fuel by measuring the refractive index of the fuel.
  • Biofuel for example, ethanol
  • Biofuels are often used in admixture with conventional fossil fuels (eg gasoline).
  • Fuel characteristics such as theoretical air-fuel ratio and calorific value are different between gasoline and ethanol. Therefore, the fuel characteristics of the ethanol-mixed gasoline change according to the ethanol concentration. For this reason, in order to appropriately control an engine of an automobile or the like that uses ethanol-mixed gasoline, a device for detecting the ethanol concentration of the fuel is required.
  • ETBE ethyl tertiary butyl ether
  • both ethanol and ETBE gasoline are used. In such areas, both ethanol blended gasoline and ETBE blended gasoline may be refueled. Ethanol and ETBE differ in fuel characteristics such as the theoretical air-fuel ratio and calorific value. Therefore, in order to perform proper engine control, it is first necessary to determine whether ethanol mixed gasoline or ETBE mixed gasoline is used.
  • FIG. 11 is a diagram comparing the relative permittivity (gasoline ratio) of ETBE, ethanol, and water
  • FIG. 12 is a diagram showing the relationship between the concentration and the capacitance of ethanol mixed gasoline and ETBE mixed gasoline.
  • the relative dielectric constant differs between ethanol and ETBE.
  • the capacitance of ethanol mixed gasoline having an ethanol concentration of ⁇ % and the capacitance of ETBE mixed gasoline having an ETBE concentration of ⁇ % are both equal ⁇ .
  • the capacitance measured by the capacitance type concentration sensor is ⁇ , is ethanol blended gasoline with a concentration of ⁇ % or ETBE blended gasoline with a concentration of ⁇ % used?
  • the capacitance measured by the capacitance type concentration sensor is ⁇ , is ethanol blended gasoline with a concentration of ⁇ % or ETBE blended gasoline with a concentration of ⁇ % used?
  • the present invention has been made in view of the above points, and an object thereof is to provide a fuel property determination device for an internal combustion engine that can determine the properties of components contained in fuel.
  • a first invention is a fuel property determination apparatus for an internal combustion engine,
  • a dielectric constant detecting means for detecting a dielectric constant of fuel supplied to the internal combustion engine or a physical quantity correlated therewith as a dielectric constant parameter;
  • Fuel temperature detection means for detecting the temperature of the fuel to be detected by the relative dielectric constant detection means;
  • the detected values of the relative dielectric constant parameters are obtained at a plurality of points having different fuel temperatures, and the components contained in the fuel are determined based on the detected fuel temperatures and detected values of the relative dielectric constant parameters at the respective points.
  • Fuel property judging means for judging the property; It is characterized by providing.
  • the second invention is the first invention, wherein
  • the fuel property determining means determines which of a plurality of components having different temperature dependence characteristics of relative permittivity is contained in the fuel.
  • the third invention is the second invention, wherein
  • the fuel property determining means includes Based on the detected value of the fuel temperature and the relative dielectric constant parameter at one point of the plurality of points and the detected fuel temperature at the other point, the estimated value of the relative dielectric constant parameter at the other point
  • An estimated value calculating means for calculating for each of the plurality of components; Of the estimated values for each of the plurality of components, component determination means for determining that a component corresponding to an estimated value closest to the detected value of the relative dielectric constant parameter of the other point is contained in the fuel; It is characterized by including.
  • the fuel property determination means performs the determination when the concentration of the component in the fuel has not changed.
  • the fuel property determination means is configured to detect the fuel temperature and the relative dielectric constant parameter when the internal combustion engine is stopped, and then the fuel temperature and the relative dielectric constant when the internal combustion engine is started. The determination is performed based on the detected value of the parameter.
  • a heater capable of heating the fuel in the vicinity of the sensor unit provided in the relative dielectric constant detection means;
  • the fuel property determination means performs the determination when fuel near the sensor unit is heated by the heater.
  • the seventh invention is the sixth invention, wherein
  • the sensor unit is disposed in or near a fuel distribution passage for distributing fuel to a fuel injector of each cylinder of the internal combustion engine,
  • the heater is capable of heating the fuel in the fuel distribution passage.
  • the eighth invention is the seventh invention, wherein The fuel property determination means performs the determination at an opportunity when the heater is operated during a cold start of the internal combustion engine.
  • the first invention it is possible to determine the properties of the components contained in the fuel by detecting the relative dielectric constant parameters at a plurality of points with different fuel temperatures. For this reason, even when a plurality of types of mixed fuel may be used, the fuel property can be accurately detected.
  • the second invention it is possible to determine which of a plurality of components having different temperature dependence characteristics of relative permittivity is contained in the fuel. For this reason, it is possible to accurately determine which of a plurality of types of fuels having different components is used.
  • the properties of the components contained in the fuel can be accurately determined by a simple method.
  • the fourth invention it is possible to reliably prevent erroneous determination by executing the fuel determination when the concentration of the component in the fuel has not changed.
  • the detected value of the fuel temperature and relative dielectric constant parameter when the internal combustion engine is stopped, and the detected value of the fuel temperature and relative dielectric constant parameter when the internal combustion engine is started next time By making a determination based on the above, erroneous determination can be reliably prevented. Further, since the fuel determination is completed at the time of starting, appropriate engine control corresponding to the fuel property can be started immediately after the starting.
  • the fuel in the vicinity of the sensor unit is heated by the heater, so that the fuel determination can be executed by forcibly changing the fuel temperature in the vicinity of the sensor unit. It becomes possible.
  • the fuel temperature in the vicinity of the sensor unit can be raised by the heater for heating the fuel in the fuel distribution passage for distributing the fuel to the fuel injectors of each cylinder. For this reason, a dedicated heater is not necessary, and the cost can be reduced.
  • the fuel determination can be executed by utilizing the opportunity that the heater of the fuel distribution passage is operated during the cold start of the internal combustion engine, so that the power consumption can be reduced. Further, since the fuel determination is completed at the time of starting, appropriate engine control corresponding to the fuel property can be started immediately after the starting.
  • FIG. 1 is a diagram showing a fuel property determination apparatus according to Embodiment 1 of the present invention.
  • the fuel property determination apparatus according to the present embodiment is mounted on an automobile in which both an ethanol-containing fuel (for example, ethanol mixed gasoline) and an ETBE-containing fuel (for example, ETBE mixed gasoline) may be used.
  • the fuel property determination apparatus includes electrodes 10 and 12, a temperature sensor 14, and an ECU (Electronic Control Unit) 50.
  • the electrodes 10 and 12 and the temperature sensor 14 are electrically connected to the ECU 50, respectively.
  • the ECU 50 is connected to an engine ECU 70 that controls an internal combustion engine (hereinafter referred to as “engine”) (not shown) so as to be able to communicate with each other.
  • engine internal combustion engine
  • the electrodes 10 and 12 are installed inside a fuel passage 60 for sending fuel from a fuel tank (not shown) to the engine.
  • the electrodes 10 and 12 are both cylindrical, and are arranged concentrically with the small-diameter electrode 12 inserted inside the large-diameter electrode 10.
  • the center lines of the electrodes 10 and 12 are arranged so as to be parallel to the fuel flow direction of the fuel passage 60.
  • the fuel easily flows through the gap between the electrode 10 and the electrode 12, so that the fuel can be reliably prevented from staying in the gap between the electrode 10 and the electrode 12.
  • the shape and arrangement of the electrodes 10 and 12 are not limited to the illustrated configuration.
  • a temperature sensor 14 composed of, for example, a thermistor is installed.
  • the temperature sensor 14 can detect the temperature of the fuel interposed between the electrodes 10 and 12.
  • the ECU 50 has a function of detecting (measuring) the capacitance between the electrodes 10 and 12.
  • the capacitance between the electrodes 10 and 12 (hereinafter simply referred to as “capacitance”) varies according to the relative dielectric constant of the fuel interposed between the electrodes 10 and 12.
  • the relative permittivity of the ethanol-containing fuel or the ETBE-containing fuel changes depending on the concentration of ethanol contained or the concentration of ETBE. For this reason, the capacitance changes according to the ethanol concentration or the ETBE concentration.
  • FIG. 2 is a diagram showing the temperature dependence characteristics of the capacitance when ethanol is 100% and the temperature dependence characteristics of the capacitance when ETBE is 100%.
  • FIG. 3 is a graph showing the relationship between ethanol concentration, temperature and capacitance of an ethanol-containing fuel.
  • the ECU 50 stores in advance a map as shown in FIG. 3 (hereinafter referred to as “ethanol concentration calculation map”).
  • ethanol concentration calculation map When an ethanol-containing fuel is used, the ECU 50 determines the ethanol concentration based on the detected capacitance, the fuel temperature detected by the temperature sensor 14, and the ethanol concentration calculation map shown in FIG. Can be calculated.
  • the ECU 50 also stores in advance a map (hereinafter referred to as “ETBE concentration calculation map”) indicating the relationship between the ETBE concentration and temperature of the ETBE-containing fuel and the capacitance.
  • ETBE concentration calculation map a map indicating the relationship between the ETBE concentration and temperature of the ETBE-containing fuel and the capacitance.
  • FIG. 4 is a diagram for explaining the determination method.
  • FIG. 4 is a graph with time on the horizontal axis and fuel temperature and capacitance on the vertical axis.
  • the electrodes 10 and 12 and the temperature sensor 14 detect the capacitance and the fuel temperature.
  • the detected capacitance value at this time is C1
  • the detected fuel temperature value is t1.
  • an estimated value of the capacitance at the fuel temperature t2 higher than the fuel temperature t1 by a predetermined width ⁇ t is calculated.
  • ethanol has a larger change in capacitance due to temperature change than ETBE. Therefore, in FIG. 4, the change in the capacitance of the ETBE-containing fuel when the fuel temperature rises as shown in the upper graph can be estimated as indicated by a broken line A.
  • the estimated capacitance value at the fuel temperature t2 is C2.
  • the change in the capacitance of the ethanol-containing fuel when the fuel temperature similarly changes can be estimated as shown by the broken line B. Therefore, assuming that an ethanol-containing fuel is used, the estimated value of the capacitance at the fuel temperature t2 is C3. Then, when the actual fuel temperature rises to t2 (time T2), the actual capacitance is detected. This detected value is C4. If ETBE-containing fuel is used, the capacitance detection value C4 should be close to the estimated value C2, and if ethanol-containing fuel is used, the capacitance detection value C4 is The value should be close to the estimated value C3. Therefore, by comparing whether the capacitance detection value C4 is close to the estimated value C2 or the estimated value C3, it can be determined whether the fuel is an ETBE-containing fuel or an ethanol-containing fuel.
  • the estimated capacitance values C2 and C3 can be calculated as follows.
  • FIG. 5 is a diagram showing the relationship between ethanol concentration, temperature, and capacitance of an ethanol-containing fuel.
  • FIG. 6 is a diagram for explaining a method of calculating the estimated capacitance values C2 and C3.
  • the map shown in FIG. 5 corresponds to the ethanol concentration calculation map shown in FIG. 3 rewritten with the horizontal axis as the fuel temperature. Therefore, the map shown in FIG. 5 can be derived from the ethanol concentration calculation map.
  • a map of ethanol concentration is selected from the map shown in FIG. 5 so that the capacitance becomes C1 when the fuel temperature is t1.
  • the selected map is represented by D in FIG.
  • the value of the map D at the fuel temperature t2 corresponds to the estimated capacitance value C3 in the case of the ethanol-containing fuel.
  • the estimated capacitance value C2 in the case of ETBE-containing fuel can also be calculated in the same manner as described above. That is, an ETBE concentration map is selected from a map obtained by rewriting the ETBE concentration calculation map with the horizontal axis as the fuel temperature so that the capacitance is C1 when the fuel temperature is t1.
  • the selected map is represented by E in FIG.
  • the value of the map E at the fuel temperature t2 corresponds to the estimated capacitance value C2 in the case of ETBE-containing fuel.
  • FIGS. 7 and 8 are flowcharts of routines executed by the ECU 50 in the present embodiment in order to realize the above functions.
  • step 200 it is first determined whether or not the current fuel temperature has reached t1 + ⁇ t (step 200).
  • the detected capacitance value C4 at that time is acquired, and it is determined whether the detected capacitance value C4 is closer to the estimated values C2 or C3 (Ste 202). That is, in this step 202, the magnitude relationship between the absolute value of (C4-C3) and the absolute value of (C4-C2) is compared. As a result, when it is determined that C4 is closer to the estimated value C3 of ethanol, it is determined that the ethanol-containing fuel is being used (step 204).
  • the ethanol concentration calculation map shown in FIG. 3 is set as the fuel component concentration calculation map (step 206). Thereafter, the ECU 50 compares the detected capacitance and fuel temperature with the ethanol concentration calculation map to calculate the ethanol concentration, and sends the calculated ethanol concentration information to the engine ECU 70.
  • step 202 determines whether C4 is closer to the estimated value C2 of ETBE.
  • an ETBE concentration calculation map is set as a fuel component concentration calculation map (step 210).
  • the ECU 50 compares the detected capacitance and fuel temperature with the ETBE concentration calculation map to calculate the ETBE concentration, and sends the calculated ETBE concentration information to the engine ECU 70.
  • the engine ECU 70 can appropriately correct the engine control parameters (for example, the target air-fuel ratio, the fuel injection amount, the ignition timing) based on the fuel information sent from the ECU 50.
  • the interval ⁇ t between the two fuel temperatures t1 and t2 is a predetermined value, but the interval ⁇ t does not necessarily have to be a predetermined value. That is, it is assumed that the fuel temperature t2 at the second point is an arbitrary value as long as it is a predetermined value or more away from the fuel temperature t1 at the first point, and after detecting the fuel temperature t2 and the capacitance C4, (t2- The estimated values C2 and C3 of the electrostatic capacitance may be calculated based on the value of t1), and the calculated estimated values C2 and C3 may be compared with the detected value C4.
  • the fuel component concentration in the vicinity of the electrodes 10 and 12 does not change between the detection of the fuel temperature t1 and the capacitance C1 and the detection of the fuel temperature t2 and the capacitance C4. is there.
  • the fuel component concentration in the vicinity of the electrodes 10 and 12 may change midway. Therefore, in order to prevent erroneous determination reliably, the fuel component concentration in the vicinity of the electrodes 10 and 12 is detected when the fuel temperature t1 and the capacitance C1 are detected and when the fuel temperature t2 and the capacitance C4 are detected. It is desirable to take a method that ensures that there is no change. Examples of such a method include the following method.
  • Method 1 Based on the open / close sensor provided at the fuel filler opening of the fuel tank or the detected value of the fuel tank fuel gauge, the presence or absence of fuel is determined. Both the time t1 and the capacitance C1 are detected and the time when the fuel temperature t2 and the capacitance C4 are detected are entered.
  • Method 2 The fuel temperature t1 and the capacitance C1 are detected when the engine is stopped, and the fuel temperature t2 and the capacitance C4 are detected at the next engine start. There is a high possibility that the fuel temperature t1 and the fuel temperature t2 are not the same because the time is separated between the engine stop and the next engine start. On the other hand, it is considered that there is no change in the fuel component concentration in the vicinity of the electrodes 10 and 12 when the engine is stopped and when the engine is next started. Therefore, such a method is effective. This method is also advantageous in that the determination ends when the engine is started.
  • the contained component is ethanol or ETBE.
  • any component can be determined as long as it is a plurality of components having different temperature-dependent characteristics of relative permittivity. Is possible. For example, it can be determined which of ethanol and water is contained, or which of three or more components is contained.
  • the “plurality of components” referred to here includes the same type of components having different degrees of deterioration. For example, the deterioration degree of the fatty acid methyl ester component contained in the fatty acid methyl ester-containing fuel can be determined according to the present invention.
  • the capacitance between the electrodes 10 and 12 is detected.
  • the present invention is not limited as long as it detects the relative dielectric constant of fuel or the physical quantity correlated therewith. It is also applicable to.
  • the capacitance is the “relative permittivity parameter” in the first invention
  • the temperature sensor 14 is the “temperature detecting means” in the first invention
  • the electrodes 10 and 12 are used.
  • the ECU 50 executes the routine of FIG. 7 and FIG. 8
  • the “fuel property determination means” in the first aspect of the invention causes the routine of FIG. 7 to execute the routine of the third aspect of the invention.
  • the “estimated value calculating means” implements the “component determination means” according to the third aspect of the present invention by executing the processing of steps 200, 202, 204 and 208 described above.
  • Embodiment 2 FIG. Next, a second embodiment of the present invention will be described with reference to FIG. 9. The description will focus on the differences from the first embodiment described above, and the same matters will be simplified or described. Omitted.
  • FIG. 9 is a diagram showing a fuel property determining apparatus according to Embodiment 2 of the present invention.
  • the fuel property determination apparatus of the present embodiment includes a heater 18 that can heat the fuel in the vicinity of the electrodes 10 and 12. Energization of the heater 18 is controlled by the ECU 50.
  • the heater 18 when determining whether the component contained in the fuel is ethanol or ETBE, after detecting the first fuel temperature t1 and the capacitance C1, the heater 18 is energized and the electrodes The temperature of the fuel in the vicinity of 10 and 12 is increased, and the second fuel temperature t2 and the capacitance C4 are detected.
  • the fuel temperature in the vicinity of the electrodes 10 and 12 can be forcibly increased from t1 to t2, so that the fuel temperature naturally changes. There is no need to wait. For this reason, the determination of a contained component can be performed rapidly at arbitrary timings.
  • Embodiment 3 the third embodiment of the present invention will be described with reference to FIG. 10.
  • the description will focus on the differences from the above-described embodiment, and the description of the same matters will be simplified or omitted. To do.
  • FIG. 10 is a plan view showing an engine provided with the fuel property determining apparatus according to Embodiment 3 of the present invention.
  • the engine 20 in this embodiment is an in-line four-cylinder type.
  • a fuel injector 22 provided in each cylinder is connected to a delivery pipe (fuel distribution passage) 24.
  • the fuel sent from the fuel tank is distributed to the fuel injector 22 of each cylinder through the delivery pipe 24.
  • the delivery pipe 24 is provided with a heater 26 that can heat the fuel in the delivery pipe 24.
  • the engine ECU 70 energizes the heater 26 to heat the fuel in the delivery pipe 24.
  • a fuel property sensor unit 28 having an electrode for detecting capacitance and a temperature sensor is attached to the delivery pipe 24.
  • the configuration of the fuel property sensor unit 28 may be the same as that of the electrodes 10 and 12 and the temperature sensor 14 shown in FIG.
  • the contained component is ethanol or ETBE by using the opportunity that the heater 26 is activated when the engine 20 is cold started. That is, the first fuel temperature t1 and the capacitance C1 are detected before heating by the heater 26, and after the fuel temperature in the delivery pipe 24 is increased by the heating of the heater 26, the second fuel temperature t2 and static The capacitance C4 is detected.
  • the engine 20 when the engine 20 is cold started, it can be determined whether the component is ethanol or ETBE, so that appropriate engine control according to the fuel properties can be performed immediately after starting. Can be executed. Further, since the fuel property sensor unit 28 itself does not require a heater, the structure can be simplified and the cost can be reduced. In addition, the heater is not operated only for determining the fuel-containing component, but the fuel determination is performed by using the opportunity of the heater operation for promoting fuel vaporization at the cold start, so that power consumption is reduced. be able to.
  • the fuel property sensor unit 28 is provided in the delivery pipe 24.
  • the fuel property sensor unit 28 is necessarily provided in the delivery pipe 24 itself, as long as it is a place where the heat of the heater 26 can be transmitted. There is no.
  • the fuel property sensor unit 28 may be installed in the fuel passage 30 near the inlet of the delivery pipe 24.

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Abstract

Disclosed is an internal combustion engine fuel property determination device which can determine the properties of components included in fuel. The disclosed internal combustion engine fuel property determination device is provided with: a relative dielectric constant detection means which detects, as a dielectric constant parameter, either the dielectric constant of the fuel, or the physical quantity correlating with the same; a fuel temperature detection means which detects the temperature of the fuel; and a fuel property determination means which acquires dielectric constant parameter detection values at a plurality of points having different fuel temperatures, and determines the properties of components included in the fuel on the basis of the dielectric constant parameter detection value and the fuel temperature at each point. The fuel property determination means determines which of the components from among the plurality of components having different dielectric constant temperature dependency properties are included in the fuel.

Description

内燃機関の燃料性状判定装置Fuel property determination device for internal combustion engine
　本発明は、内燃機関の燃料性状判定装置に関する。 The present invention relates to a fuel property determination device for an internal combustion engine.
　内燃機関の燃費やエミッションなどの性能を優れたものとするためには、エンジン制御パラメータ（例えば、燃料噴射量、空燃比、点火時期、燃料噴射時期、ＥＧＲ率など）の値を、燃料の性状に応じて、適切な値に補正する必要がある。このため、燃料性状に応じて内燃機関を最適に制御するべく、燃料性状を検出するための各種の装置が従来より提案されている。 In order to improve the performance of the internal combustion engine such as fuel consumption and emission, the values of engine control parameters (for example, fuel injection amount, air-fuel ratio, ignition timing, fuel injection timing, EGR rate, etc.) are changed to the properties of the fuel. Therefore, it is necessary to correct to an appropriate value. For this reason, various devices for detecting the fuel property have been proposed in order to optimally control the internal combustion engine in accordance with the fuel property.
　日本特開平５－２４０８５３号公報には、燃料の屈折率を測定することによって燃料の比重を検出する装置が開示されている。 Japanese Patent Laid-Open No. 5-240853 discloses a device for detecting the specific gravity of a fuel by measuring the refractive index of the fuel.
日本特開平５－２４０８５３号公報Japanese Patent Laid-Open No. 5-240853 日本特開平１０－１１０６３６号公報Japanese Unexamined Patent Publication No. 10-110636 日本特開２００８－２７４８２５号公報Japanese Unexamined Patent Publication No. 2008-274825
　バイオマスから生産されるバイオ燃料（例えばエタノール）を内燃機関の燃料として用いる動きが広まっている。バイオ燃料は、従来の化石燃料（例えばガソリン）と混合して用いられることが多い。ガソリンとエタノールとでは、理論空燃比や発熱量等の燃料特性が異なる。従って、エタノール混合ガソリンの燃料特性は、そのエタノール濃度に応じて変化する。このため、エタノール混合ガソリンを使用する自動車等のエンジンを適切に制御するためには、燃料のエタノール濃度を検出する装置が必要となる。 The movement to use biofuel (for example, ethanol) produced from biomass as fuel for internal combustion engines is widespread. Biofuels are often used in admixture with conventional fossil fuels (eg gasoline). Fuel characteristics such as theoretical air-fuel ratio and calorific value are different between gasoline and ethanol. Therefore, the fuel characteristics of the ethanol-mixed gasoline change according to the ethanol concentration. For this reason, in order to appropriately control an engine of an automobile or the like that uses ethanol-mixed gasoline, a device for detecting the ethanol concentration of the fuel is required.
　ガソリンとエタノールとでは、比誘電率が大きく異なる。このため、エタノール混合ガソリン中に浸漬した一対の電極間の静電容量は、そのエタノール濃度に応じて変化する。このことを利用して、上記静電容量を測定することによってエタノール濃度を検出する、静電容量式濃度センサが従来より知られている。 The relative permittivity of gasoline and ethanol is greatly different. For this reason, the electrostatic capacitance between a pair of electrodes immersed in ethanol mixed gasoline changes according to the ethanol concentration. A capacitance type concentration sensor that utilizes this fact to detect the ethanol concentration by measuring the capacitance is conventionally known.
　また、エタノールを直接ガソリンと混合するのではなく、エタノールと、石油系ガスであるイソブテンとを合成することによりエチル・ターシャリー・ブチル・エーテル（以下、「ＥＴＢＥ」と記す）を製造し、このＥＴＢＥをガソリンに混合した燃料を使用する動きもある。このＥＴＢＥ混合ガソリンのＥＴＢＥ濃度についても、上述した静電容量式濃度センサによって検出することが可能である。 Also, instead of directly mixing ethanol with gasoline, ethyl tertiary butyl ether (hereinafter referred to as “ETBE”) is manufactured by synthesizing ethanol and isobutene, which is a petroleum-based gas. There is also a movement to use a fuel in which ETBE is mixed with gasoline. The ETBE concentration of this ETBE mixed gasoline can also be detected by the capacitance type concentration sensor described above.
　しかしながら、地域によっては、エタノール混合ガソリンとＥＴＢＥ混合ガソリンとが共に用いられている。そのような地域では、エタノール混合ガソリンとＥＴＢＥ混合ガソリンとの両方が自動車に給油される可能性がある。エタノールとＥＴＢＥとでは、理論空燃比や発熱量等の燃料特性が異なる。従って、適正なエンジン制御を行うためには、まず、エタノール混合ガソリンが使用されているのか、ＥＴＢＥ混合ガソリンが使用されているのかを判別することが必要となる。 However, in some regions, both ethanol and ETBE gasoline are used. In such areas, both ethanol blended gasoline and ETBE blended gasoline may be refueled. Ethanol and ETBE differ in fuel characteristics such as the theoretical air-fuel ratio and calorific value. Therefore, in order to perform proper engine control, it is first necessary to determine whether ethanol mixed gasoline or ETBE mixed gasoline is used.
　図１１は、ＥＴＢＥ、エタノール、水の比誘電率（ガソリン比）を比較した図であり、図１２は、エタノール混合ガソリンおよびＥＴＢＥ混合ガソリンの濃度と静電容量との関係を示す図である。図１１に示すように、エタノールとＥＴＢＥとでは、比誘電率が異なる。しかしながら、静電容量式濃度センサによって静電容量を測定しただけでは、エタノール混合ガソリンであるかＥＴＢＥ混合ガソリンであるかを区別できない場合がある。例えば、図１２に示すように、エタノール濃度β％のエタノール混合ガソリンの静電容量と、ＥＴＢＥ濃度γ％のＥＴＢＥ混合ガソリンの静電容量とは、共に等しくαである。このため、静電容量式濃度センサによる静電容量の測定値がαであった場合、濃度β％のエタノール混合ガソリンが使用されているのか、濃度γ％のＥＴＢＥ混合ガソリンが使用されているのかの区別がつかないという問題がある。 FIG. 11 is a diagram comparing the relative permittivity (gasoline ratio) of ETBE, ethanol, and water, and FIG. 12 is a diagram showing the relationship between the concentration and the capacitance of ethanol mixed gasoline and ETBE mixed gasoline. As shown in FIG. 11, the relative dielectric constant differs between ethanol and ETBE. However, there are cases where it is not possible to distinguish between ethanol-mixed gasoline and ETBE-mixed gasoline only by measuring the capacitance with a capacitance-type concentration sensor. For example, as shown in FIG. 12, the capacitance of ethanol mixed gasoline having an ethanol concentration of β% and the capacitance of ETBE mixed gasoline having an ETBE concentration of γ% are both equal α. For this reason, if the capacitance measured by the capacitance type concentration sensor is α, is ethanol blended gasoline with a concentration of β% or ETBE blended gasoline with a concentration of γ% used? There is a problem that cannot be distinguished.
　本発明は、上記の点に鑑みてなされたものであり、燃料に含有されている成分の性状を判定することのできる内燃機関の燃料性状判定装置を提供することを目的とする。 The present invention has been made in view of the above points, and an object thereof is to provide a fuel property determination device for an internal combustion engine that can determine the properties of components contained in fuel.
　第１の発明は、上記の目的を達成するため、内燃機関の燃料性状判定装置であって、
　内燃機関に供給される燃料の比誘電率またはこれと相関する物理量を比誘電率パラメータとして検出する比誘電率検出手段と、
　前記比誘電率検出手段の検出対象となる燃料の温度を検出する燃料温度検出手段と、
　前記燃料温度が異なる複数の点において前記比誘電率パラメータの検出値を取得し、それら各点の前記燃料温度および前記比誘電率パラメータの検出値に基づいて、前記燃料に含有されている成分の性状を判定する燃料性状判定手段と、
　を備えることを特徴とする。 In order to achieve the above object, a first invention is a fuel property determination apparatus for an internal combustion engine,
A dielectric constant detecting means for detecting a dielectric constant of fuel supplied to the internal combustion engine or a physical quantity correlated therewith as a dielectric constant parameter;
Fuel temperature detection means for detecting the temperature of the fuel to be detected by the relative dielectric constant detection means;
The detected values of the relative dielectric constant parameters are obtained at a plurality of points having different fuel temperatures, and the components contained in the fuel are determined based on the detected fuel temperatures and detected values of the relative dielectric constant parameters at the respective points. Fuel property judging means for judging the property;
It is characterized by providing.
　また、第２の発明は、第１の発明において、
　前記燃料性状判定手段は、比誘電率の温度依存特性が異なる複数の成分のうちの何れが前記燃料に含有されているかを判定することを特徴とする。 The second invention is the first invention, wherein
The fuel property determining means determines which of a plurality of components having different temperature dependence characteristics of relative permittivity is contained in the fuel.
　また、第３の発明は、第２の発明において、
　前記燃料性状判定手段は、
　前記複数の点のうちの一の点における前記燃料温度および前記比誘電率パラメータの検出値と、他の点の前記燃料温度とに基づいて、前記他の点の前記比誘電率パラメータの推定値を前記複数の成分毎に算出する推定値算出手段と、
　前記複数の成分毎の前記推定値のうち、前記他の点の前記比誘電率パラメータの検出値に最も近い推定値に対応する成分が前記燃料に含有されていると判定する成分判定手段と、
　を含むことを特徴とする。 The third invention is the second invention, wherein
The fuel property determining means includes
Based on the detected value of the fuel temperature and the relative dielectric constant parameter at one point of the plurality of points and the detected fuel temperature at the other point, the estimated value of the relative dielectric constant parameter at the other point An estimated value calculating means for calculating for each of the plurality of components;
Of the estimated values for each of the plurality of components, component determination means for determining that a component corresponding to an estimated value closest to the detected value of the relative dielectric constant parameter of the other point is contained in the fuel;
It is characterized by including.
　また、第４の発明は、第１乃至第３の発明の何れかにおいて、
　前記燃料性状判定手段は、前記燃料中の前記成分の濃度が変化していないときに、前記判定を実行することを特徴とする。 According to a fourth invention, in any one of the first to third inventions,
The fuel property determination means performs the determination when the concentration of the component in the fuel has not changed.
　また、第５の発明は、第１乃至第４の発明の何れかにおいて、
　前記燃料性状判定手段は、前記内燃機関が停止されたときの前記燃料温度および前記比誘電率パラメータの検出値と、その次に前記内燃機関が始動されたときの前記燃料温度および前記比誘電率パラメータの検出値とに基づいて前記判定を実行することを特徴とする。 According to a fifth invention, in any one of the first to fourth inventions,
The fuel property determination means is configured to detect the fuel temperature and the relative dielectric constant parameter when the internal combustion engine is stopped, and then the fuel temperature and the relative dielectric constant when the internal combustion engine is started. The determination is performed based on the detected value of the parameter.
　また、第６の発明は、第１乃至第５の発明の何れかにおいて、
　前記比誘電率検出手段が備えるセンサ部の近傍の燃料を加熱可能なヒータを備え、
　前記燃料性状判定手段は、前記ヒータによって前記センサ部の近傍の燃料が加熱される際に、前記判定を実行することを特徴とする。 According to a sixth invention, in any one of the first to fifth inventions,
A heater capable of heating the fuel in the vicinity of the sensor unit provided in the relative dielectric constant detection means;
The fuel property determination means performs the determination when fuel near the sensor unit is heated by the heater.
　また、第７の発明は、第６の発明において、
　前記センサ部は、前記内燃機関の各気筒の燃料インジェクタに燃料を分配する燃料分配通路またはその近傍に配置されており、
　前記ヒータは、前記燃料分配通路内の燃料を加熱可能であることを特徴とする。 The seventh invention is the sixth invention, wherein
The sensor unit is disposed in or near a fuel distribution passage for distributing fuel to a fuel injector of each cylinder of the internal combustion engine,
The heater is capable of heating the fuel in the fuel distribution passage.
　また、第８の発明は、第７の発明において、
　前記燃料性状判定手段は、前記内燃機関の冷間始動時に前記ヒータが作動される機会に、前記判定を実行することを特徴とする。 The eighth invention is the seventh invention, wherein
The fuel property determination means performs the determination at an opportunity when the heater is operated during a cold start of the internal combustion engine.
　第１の発明によれば、燃料温度が異なる複数の点において比誘電率パラメータを検出することにより、燃料に含有されている成分の性状を判定することが可能となる。このため、複数の種別の混合燃料が使用される可能性のある場合においても、燃料性状を正確に検出することができる。 According to the first invention, it is possible to determine the properties of the components contained in the fuel by detecting the relative dielectric constant parameters at a plurality of points with different fuel temperatures. For this reason, even when a plurality of types of mixed fuel may be used, the fuel property can be accurately detected.
　第２の発明によれば、比誘電率の温度依存特性が異なる複数の成分のうちの何れが燃料に含有されているか判定することができる。このため、含有される成分が異なる複数種別の燃料のうちの何れが使用されているかを正確に判定することができる。 According to the second invention, it is possible to determine which of a plurality of components having different temperature dependence characteristics of relative permittivity is contained in the fuel. For this reason, it is possible to accurately determine which of a plurality of types of fuels having different components is used.
　第３の発明によれば、燃料に含有されている成分の性状を簡単な方法で正確に判定することができる。 According to the third invention, the properties of the components contained in the fuel can be accurately determined by a simple method.
　第４の発明によれば、燃料中の成分の濃度が変化していないときに燃料判定を実行することにより、誤判定を確実に防止することができる。 According to the fourth invention, it is possible to reliably prevent erroneous determination by executing the fuel determination when the concentration of the component in the fuel has not changed.
　第５の発明によれば、内燃機関が停止されたときの燃料温度および比誘電率パラメータの検出値と、その次に内燃機関が始動されたときの燃料温度および比誘電率パラメータの検出値とに基づいて判定を行うことにより、誤判定を確実に防止することができる。また、始動時に燃料判定が終了するので、燃料性状に応じた適切なエンジン制御を始動直後から開始することができる。 According to the fifth aspect of the present invention, the detected value of the fuel temperature and relative dielectric constant parameter when the internal combustion engine is stopped, and the detected value of the fuel temperature and relative dielectric constant parameter when the internal combustion engine is started next time By making a determination based on the above, erroneous determination can be reliably prevented. Further, since the fuel determination is completed at the time of starting, appropriate engine control corresponding to the fuel property can be started immediately after the starting.
　第６の発明によれば、ヒータによってセンサ部の近傍の燃料が加熱することにより、センサ部近傍の燃料温度を強制的に変化させて燃料判定を実行することができるので、迅速な燃料判定が可能となる。 According to the sixth aspect of the invention, the fuel in the vicinity of the sensor unit is heated by the heater, so that the fuel determination can be executed by forcibly changing the fuel temperature in the vicinity of the sensor unit. It becomes possible.
　第７の発明によれば、各気筒の燃料インジェクタに燃料を分配する燃料分配通路内の燃料を加熱するヒータによってセンサ部近傍の燃料温度を上昇させることができる。このため、専用のヒータが不要となり、コスト低減が図れる。 According to the seventh invention, the fuel temperature in the vicinity of the sensor unit can be raised by the heater for heating the fuel in the fuel distribution passage for distributing the fuel to the fuel injectors of each cylinder. For this reason, a dedicated heater is not necessary, and the cost can be reduced.
　第８の発明によれば、内燃機関の冷間始動時に燃料分配通路のヒータが作動される機会を利用して燃料判定を実行することができるので、消費電力を節減することができる。また、始動時に燃料判定が終了するので、燃料性状に応じた適切なエンジン制御を始動直後から開始することができる。 According to the eighth aspect of the invention, the fuel determination can be executed by utilizing the opportunity that the heater of the fuel distribution passage is operated during the cold start of the internal combustion engine, so that the power consumption can be reduced. Further, since the fuel determination is completed at the time of starting, appropriate engine control corresponding to the fuel property can be started immediately after the starting.
本発明の実施の形態１の燃料性状判定装置を示す図である。It is a figure which shows the fuel property determination apparatus of Embodiment 1 of this invention. エタノール１００％の場合の静電容量の温度依存特性、および、ＥＴＢＥ１００％の場合の静電容量の温度依存特性を示す図である。It is a figure which shows the temperature dependence characteristic of the electrostatic capacitance in the case of 100% of ethanol, and the temperature dependence characteristic of the electrostatic capacitance in the case of ETBE100%. エタノール含有燃料のエタノール濃度、温度および静電容量の関係を示す図である。It is a figure which shows the ethanol concentration of ethanol containing fuel, temperature, and the relationship of an electrostatic capacitance. エタノール含有燃料であるかＥＴＢＥ含有燃料であるかを判別する方法を説明するための図である。It is a figure for demonstrating the method to discriminate | determine whether it is an ethanol containing fuel or an ETBE containing fuel. エタノール含有燃料のエタノール濃度、温度および静電容量の関係を示す図である。It is a figure which shows the ethanol concentration of ethanol containing fuel, temperature, and the relationship of an electrostatic capacitance. 静電容量の推定値を算出する方法を説明するための図である。It is a figure for demonstrating the method of calculating the estimated value of an electrostatic capacitance. 本発明の実施の形態１において実行されるルーチンのフローチャートである。It is a flowchart of the routine performed in Embodiment 1 of the present invention. 本発明の実施の形態１において実行されるルーチンのフローチャートである。It is a flowchart of the routine performed in Embodiment 1 of the present invention. 本発明の実施の形態２の燃料性状判定装置を示す図である。It is a figure which shows the fuel property determination apparatus of Embodiment 2 of this invention. 本発明の実施の形態３の燃料性状判定装置が備えられたエンジンを示す平面図である。It is a top view which shows the engine provided with the fuel property determination apparatus of Embodiment 3 of this invention. ＥＴＢＥ、エタノール、水の比誘電率（ガソリン比）を比較した図である。It is the figure which compared the dielectric constant (gasoline ratio) of ETBE, ethanol, and water. エタノール混合ガソリンおよびＥＴＢＥ混合ガソリンの濃度と静電容量との関係を示す図である。It is a figure which shows the relationship between the density | concentration of an ethanol mixed gasoline and ETBE mixed gasoline, and an electrostatic capacitance.
　以下、図面を参照して本発明の実施の形態について説明する。なお、各図において共通する要素には、同一の符号を付して、重複する説明を省略する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.
実施の形態１．
　図１は、本発明の実施の形態１の燃料性状判定装置を示す図である。本実施形態の燃料性状判定装置は、エタノール含有燃料（例えばエタノール混合ガソリン）と、ＥＴＢＥ含有燃料（例えばＥＴＢＥ混合ガソリン）との双方が使用される可能性のある自動車に搭載されるものである。図１に示すように、この燃料性状判定装置は、電極１０，１２と、温度センサ１４と、ＥＣＵ（Electronic Control Unit）５０とを備えている。電極１０，１２および温度センサ１４は、それぞれ、ＥＣＵ５０と電気的に接続されている。また、ＥＣＵ５０は、図示しない内燃機関（以下、「エンジン」と称する）を制御するエンジンＥＣＵ７０と相互に通信可能に接続されている。 Embodiment 1 FIG.
FIG. 1 is a diagram showing a fuel property determination apparatus according to Embodiment 1 of the present invention. The fuel property determination apparatus according to the present embodiment is mounted on an automobile in which both an ethanol-containing fuel (for example, ethanol mixed gasoline) and an ETBE-containing fuel (for example, ETBE mixed gasoline) may be used. As shown in FIG. 1, the fuel property determination apparatus includes electrodes 10 and 12, a temperature sensor 14, and an ECU (Electronic Control Unit) 50. The electrodes 10 and 12 and the temperature sensor 14 are electrically connected to the ECU 50, respectively. The ECU 50 is connected to an engine ECU 70 that controls an internal combustion engine (hereinafter referred to as “engine”) (not shown) so as to be able to communicate with each other.
　電極１０，１２は、図示しない燃料タンクからエンジンへ燃料を送るための燃料通路６０の内部に設置されている。電極１０，１２は、共に円筒形をなしており、大径の電極１０の内側に小径の電極１２が挿入された状態で同心的に配置されている。図示の構成では、電極１０，１２の中心線が燃料通路６０の燃料流れ方向と平行となるように配置されている。これにより、電極１０と電極１２との隙間を燃料が流れ易いので、電極１０と電極１２との隙間に燃料が滞留することを確実に防止することができる。ただし、本発明では、電極１０，１２の形状や配置は、図示の構成に限定されるものではない。 The electrodes 10 and 12 are installed inside a fuel passage 60 for sending fuel from a fuel tank (not shown) to the engine. The electrodes 10 and 12 are both cylindrical, and are arranged concentrically with the small-diameter electrode 12 inserted inside the large-diameter electrode 10. In the illustrated configuration, the center lines of the electrodes 10 and 12 are arranged so as to be parallel to the fuel flow direction of the fuel passage 60. As a result, the fuel easily flows through the gap between the electrode 10 and the electrode 12, so that the fuel can be reliably prevented from staying in the gap between the electrode 10 and the electrode 12. However, in the present invention, the shape and arrangement of the electrodes 10 and 12 are not limited to the illustrated configuration.
　電極１０，１２の近傍には、例えばサーミスタなどで構成される温度センサ１４が設置されている。この温度センサ１４によれば、電極１０，１２間に介在する燃料の温度を検出することができる。 In the vicinity of the electrodes 10 and 12, a temperature sensor 14 composed of, for example, a thermistor is installed. The temperature sensor 14 can detect the temperature of the fuel interposed between the electrodes 10 and 12.
　ＥＣＵ５０は、電極１０，１２間の静電容量を検出（測定）する機能を有している。電極１０，１２間の静電容量（以下、単に「静電容量」と称する）は、電極１０，１２間に介在する燃料の比誘電率に応じて変化する。エタノール含有燃料、あるいはＥＴＢＥ含有燃料は、含まれるエタノールの濃度あるいはＥＴＢＥの濃度に応じて比誘電率が変化する。このため、静電容量は、エタノール濃度あるいはＥＴＢＥ濃度に応じて変化する。 The ECU 50 has a function of detecting (measuring) the capacitance between the electrodes 10 and 12. The capacitance between the electrodes 10 and 12 (hereinafter simply referred to as “capacitance”) varies according to the relative dielectric constant of the fuel interposed between the electrodes 10 and 12. The relative permittivity of the ethanol-containing fuel or the ETBE-containing fuel changes depending on the concentration of ethanol contained or the concentration of ETBE. For this reason, the capacitance changes according to the ethanol concentration or the ETBE concentration.
　また、エタノールやＥＴＢＥは、それ自体の比誘電率が温度によって変化する。このため、静電容量は、温度によっても変化する。図２は、エタノール１００％の場合の静電容量の温度依存特性、および、ＥＴＢＥ１００％の場合の静電容量の温度依存特性を示す図である。 Also, the relative dielectric constant of ethanol and ETBE changes with temperature. For this reason, an electrostatic capacitance changes also with temperature. FIG. 2 is a diagram showing the temperature dependence characteristics of the capacitance when ethanol is 100% and the temperature dependence characteristics of the capacitance when ETBE is 100%.
　このようなことから、エタノール含有燃料あるいはＥＴＢＥ含有燃料の静電容量は、その濃度と温度とに応じて変化する。図３は、エタノール含有燃料のエタノール濃度、温度および静電容量の関係を示す図である。ＥＣＵ５０には、図３のようなマップ（以下、「エタノール濃度算出マップ」と称する）が予め記憶されている。エタノール含有燃料が使用されている場合には、ＥＣＵ５０は、検出された静電容量と、温度センサ１４により検出された燃料温度と、図３に示すエタノール濃度算出マップとに基づいて、エタノール濃度を算出することができる。また、図示を省略するが、ＥＣＵ５０には、ＥＴＢＥ含有燃料のＥＴＢＥ濃度および温度と、静電容量との関係を示すマップ（以下、「ＥＴＢＥ濃度算出マップ」と称する）も予め記憶されている。ＥＴＢＥ含有燃料が使用されている場合には、ＥＣＵ５０は、検出された静電容量と、温度センサ１４により検出された燃料温度と、そのＥＴＢＥ濃度算出マップとに基づいて、ＥＴＢＥ濃度を算出することができる。 For this reason, the capacitance of ethanol-containing fuel or ETBE-containing fuel varies depending on its concentration and temperature. FIG. 3 is a graph showing the relationship between ethanol concentration, temperature and capacitance of an ethanol-containing fuel. The ECU 50 stores in advance a map as shown in FIG. 3 (hereinafter referred to as “ethanol concentration calculation map”). When an ethanol-containing fuel is used, the ECU 50 determines the ethanol concentration based on the detected capacitance, the fuel temperature detected by the temperature sensor 14, and the ethanol concentration calculation map shown in FIG. Can be calculated. Although not shown, the ECU 50 also stores in advance a map (hereinafter referred to as “ETBE concentration calculation map”) indicating the relationship between the ETBE concentration and temperature of the ETBE-containing fuel and the capacitance. When the ETBE-containing fuel is used, the ECU 50 calculates the ETBE concentration based on the detected capacitance, the fuel temperature detected by the temperature sensor 14, and the ETBE concentration calculation map. Can do.
　しかしながら、前述したように、単に静電容量を検出しただけでは、エタノール含有燃料が使用されているのかＥＴＢＥ含有燃料が使用されているのかの区別がつかないという問題がある。この問題に対し、本実施形態では、エタノールおよびＥＴＢＥの比誘電率（静電容量）の温度依存特性の違い（図２）を利用して、エタノール含有燃料であるかＥＴＢＥ含有燃料であるかを判別することとした。図４は、その判別方法を説明するための図である。 However, as described above, there is a problem that it is not possible to distinguish whether an ethanol-containing fuel or an ETBE-containing fuel is used by simply detecting the capacitance. In order to solve this problem, in the present embodiment, the difference between the temperature dependence characteristics of the relative dielectric constant (capacitance) between ethanol and ETBE (FIG. 2) is used to determine whether the fuel is ethanol-containing fuel or ETBE-containing fuel. It was decided to distinguish. FIG. 4 is a diagram for explaining the determination method.
　図４は、横軸に時間をとり、縦軸に燃料温度および静電容量をとったグラフである。まず、時刻Ｔ１において、電極１０，１２および温度センサ１４により、静電容量および燃料温度を検出する。このときの静電容量の検出値をＣ１とし、燃料温度の検出値をｔ１とする。続いて、燃料温度ｔ１よりも所定幅Δｔだけ高い燃料温度ｔ２のときの、静電容量の推定値を算出する。図２に示すように、エタノールの方がＥＴＢＥと比べて、温度変化に伴う静電容量の変化が大きい。このため、図４中で、燃料温度が上のグラフのように上昇したときのＥＴＢＥ含有燃料の静電容量の変化は、破線Ａのように推定できる。従って、ＥＴＢＥ含有燃料が使用されているとすると、燃料温度ｔ２のときの静電容量の推定値はＣ２となる。一方、燃料温度が同様に変化したときのエタノール含有燃料の静電容量の変化は、破線Ｂのように推定できる。従って、エタノール含有燃料が使用されているとすると、燃料温度ｔ２のときの静電容量の推定値はＣ３となる。そして、実際の燃料温度がｔ２まで上昇した時点（時刻Ｔ２）において、実際の静電容量を検出する。この検出値をＣ４とする。ＥＴＢＥ含有燃料が使用されているのであれば、静電容量検出値Ｃ４は推定値Ｃ２に近い値になるはずであり、エタノール含有燃料が使用されているのであれば、静電容量検出値Ｃ４は推定値Ｃ３に近い値になるはずである。よって、静電容量検出値Ｃ４が推定値Ｃ２に近いか推定値Ｃ３に近いかを比較することにより、ＥＴＢＥ含有燃料であるかエタノール含有燃料であるかを判別することができる。 FIG. 4 is a graph with time on the horizontal axis and fuel temperature and capacitance on the vertical axis. First, at time T1, the electrodes 10 and 12 and the temperature sensor 14 detect the capacitance and the fuel temperature. The detected capacitance value at this time is C1, and the detected fuel temperature value is t1. Subsequently, an estimated value of the capacitance at the fuel temperature t2 higher than the fuel temperature t1 by a predetermined width Δt is calculated. As shown in FIG. 2, ethanol has a larger change in capacitance due to temperature change than ETBE. Therefore, in FIG. 4, the change in the capacitance of the ETBE-containing fuel when the fuel temperature rises as shown in the upper graph can be estimated as indicated by a broken line A. Therefore, assuming that the ETBE-containing fuel is used, the estimated capacitance value at the fuel temperature t2 is C2. On the other hand, the change in the capacitance of the ethanol-containing fuel when the fuel temperature similarly changes can be estimated as shown by the broken line B. Therefore, assuming that an ethanol-containing fuel is used, the estimated value of the capacitance at the fuel temperature t2 is C3. Then, when the actual fuel temperature rises to t2 (time T2), the actual capacitance is detected. This detected value is C4. If ETBE-containing fuel is used, the capacitance detection value C4 should be close to the estimated value C2, and if ethanol-containing fuel is used, the capacitance detection value C4 is The value should be close to the estimated value C3. Therefore, by comparing whether the capacitance detection value C4 is close to the estimated value C2 or the estimated value C3, it can be determined whether the fuel is an ETBE-containing fuel or an ethanol-containing fuel.
　静電容量の推定値Ｃ２およびＣ３は、次のようにして算出することができる。図５は、エタノール含有燃料のエタノール濃度、温度および静電容量の関係を示す図である。図６は、静電容量の推定値Ｃ２およびＣ３を算出する方法を説明するための図である。 The estimated capacitance values C2 and C3 can be calculated as follows. FIG. 5 is a diagram showing the relationship between ethanol concentration, temperature, and capacitance of an ethanol-containing fuel. FIG. 6 is a diagram for explaining a method of calculating the estimated capacitance values C2 and C3.
　図５に示すマップは、図３に示すエタノール濃度算出マップを、横軸を燃料温度として書き直したものに相当する。このため、図５に示すマップは、エタノール濃度算出マップから導出することができる。燃料温度ｔ１のときの静電容量Ｃ１を検出したら、図５に示すマップから、燃料温度がｔ１のときに静電容量がＣ１となるようなエタノール濃度のマップを選択する。その選択したマップを図６中のＤで表す。図６に示すように、燃料温度ｔ２のときのマップＤの値が、エタノール含有燃料の場合の静電容量推定値Ｃ３に相当する。 The map shown in FIG. 5 corresponds to the ethanol concentration calculation map shown in FIG. 3 rewritten with the horizontal axis as the fuel temperature. Therefore, the map shown in FIG. 5 can be derived from the ethanol concentration calculation map. When the capacitance C1 at the fuel temperature t1 is detected, a map of ethanol concentration is selected from the map shown in FIG. 5 so that the capacitance becomes C1 when the fuel temperature is t1. The selected map is represented by D in FIG. As shown in FIG. 6, the value of the map D at the fuel temperature t2 corresponds to the estimated capacitance value C3 in the case of the ethanol-containing fuel.
　ＥＴＢＥ含有燃料の場合の静電容量の推定値Ｃ２についても、上記と同様にして、算出することができる。すなわち、ＥＴＢＥ濃度算出マップを横軸を燃料温度として書き直したマップから、燃料温度がｔ１のときに静電容量がＣ１となるようなＥＴＢＥ濃度のマップを選択する。その選択したマップを図６中のＥで表す。図６に示すように、燃料温度ｔ２のときのマップＥの値が、ＥＴＢＥ含有燃料の場合の静電容量推定値Ｃ２に相当する。 The estimated capacitance value C2 in the case of ETBE-containing fuel can also be calculated in the same manner as described above. That is, an ETBE concentration map is selected from a map obtained by rewriting the ETBE concentration calculation map with the horizontal axis as the fuel temperature so that the capacitance is C1 when the fuel temperature is t1. The selected map is represented by E in FIG. As shown in FIG. 6, the value of the map E at the fuel temperature t2 corresponds to the estimated capacitance value C2 in the case of ETBE-containing fuel.
　図７および図８は、上記の機能を実現するために本実施形態においてＥＣＵ５０が実行するルーチンのフローチャートである。図７に示すルーチンによれば、まず、現在の燃料温度の検出値ｔ１および静電容量の検出値Ｃ１が取得される（ステップ１００）。続いて、燃料温度ｔ１のときに静電容量Ｃ１となるような、エタノール濃度のマップおよびＥＴＢＥ濃度のマップを導出する（ステップ１０２）。このステップ１０２で導出されたマップに基づき、燃料温度がｔ１＋Δｔ（＝ｔ２）となったときの、ＥＴＢＥ含有燃料の静電容量推定値Ｃ２と、エタノール含有燃料の静電容量推定値Ｃ３とを算出する（ステップ１０４）。ステップ１０２および１０４の処理は、図５および図６を参照して説明したとおりである。 FIGS. 7 and 8 are flowcharts of routines executed by the ECU 50 in the present embodiment in order to realize the above functions. According to the routine shown in FIG. 7, first, the current fuel temperature detection value t1 and the capacitance detection value C1 are obtained (step 100). Subsequently, a map of ethanol concentration and a map of ETBE concentration that leads to the capacitance C1 at the fuel temperature t1 are derived (step 102). Based on the map derived in step 102, the estimated capacitance value C2 of the ETBE-containing fuel and the estimated capacitance value C3 of the ethanol-containing fuel when the fuel temperature becomes t1 + Δt (= t2) are calculated. (Step 104). The processing in steps 102 and 104 is as described with reference to FIGS.
　図７のルーチンの実行が終了すると、図８に示すルーチンが実行される。図８のルーチンによれば、まず、現在の燃料温度がｔ１＋Δｔに達したかどうかが判定される（ステップ２００）。現在の燃料温度がｔ１＋Δｔに達した場合には、その時点での静電容量の検出値Ｃ４が取得され、その静電容量検出値Ｃ４が推定値Ｃ２およびＣ３の何れに近いかが判別される（ステップ２０２）。すなわち、このステップ２０２では、（Ｃ４－Ｃ３）の絶対値と、（Ｃ４－Ｃ２）の絶対値との大小関係が比較される。その結果、Ｃ４がエタノールの推定値Ｃ３の方に近いと判別された場合には、エタノール含有燃料が使用されていると判定される（ステップ２０４）。この場合には、燃料成分濃度算出用のマップとして、図３に示すエタノール濃度算出マップがセットされる（ステップ２０６）。これ以降、ＥＣＵ５０は、検出された静電容量および燃料温度をエタノール濃度算出マップと照合することにより、エタノール濃度を算出し、その算出したエタノール濃度の情報をエンジンＥＣＵ７０に送る。 7 is completed, the routine shown in FIG. 8 is executed. According to the routine of FIG. 8, it is first determined whether or not the current fuel temperature has reached t1 + Δt (step 200). When the current fuel temperature reaches t1 + Δt, the detected capacitance value C4 at that time is acquired, and it is determined whether the detected capacitance value C4 is closer to the estimated values C2 or C3 ( Step 202). That is, in this step 202, the magnitude relationship between the absolute value of (C4-C3) and the absolute value of (C4-C2) is compared. As a result, when it is determined that C4 is closer to the estimated value C3 of ethanol, it is determined that the ethanol-containing fuel is being used (step 204). In this case, the ethanol concentration calculation map shown in FIG. 3 is set as the fuel component concentration calculation map (step 206). Thereafter, the ECU 50 compares the detected capacitance and fuel temperature with the ethanol concentration calculation map to calculate the ethanol concentration, and sends the calculated ethanol concentration information to the engine ECU 70.
　一方、上記ステップ２０２で、Ｃ４がＥＴＢＥの推定値Ｃ２の方に近いと判別された場合には、ＥＴＢＥ含有燃料が使用されていると判定される（ステップ２０８）。この場合には、燃料成分濃度算出用のマップとして、ＥＴＢＥ濃度算出マップがセットされる（ステップ２１０）。これ以降、ＥＣＵ５０は、検出された静電容量および燃料温度をＥＴＢＥ濃度算出マップと照合することにより、ＥＴＢＥ濃度を算出し、その算出したＥＴＢＥ濃度の情報をエンジンＥＣＵ７０に送る。 On the other hand, if it is determined in step 202 that C4 is closer to the estimated value C2 of ETBE, it is determined that the ETBE-containing fuel is being used (step 208). In this case, an ETBE concentration calculation map is set as a fuel component concentration calculation map (step 210). Thereafter, the ECU 50 compares the detected capacitance and fuel temperature with the ETBE concentration calculation map to calculate the ETBE concentration, and sends the calculated ETBE concentration information to the engine ECU 70.
　以上説明したように、本実施形態では、燃料に含まれる成分がエタノールであるかＥＴＢＥであるかを精度良く判定することができる。このため、エンジンＥＣＵ７０では、ＥＣＵ５０から送られる燃料情報に基づいて、エンジン制御パラメータ（例えば、目標空燃比、燃料噴射量、点火時期など）を適切に補正することができる。 As described above, in this embodiment, it is possible to accurately determine whether the component contained in the fuel is ethanol or ETBE. Therefore, the engine ECU 70 can appropriately correct the engine control parameters (for example, the target air-fuel ratio, the fuel injection amount, the ignition timing) based on the fuel information sent from the ECU 50.
　なお、本実施形態では、２点の燃料温度ｔ１およびｔ２の間隔Δｔを所定値としているが、間隔Δｔは必ずしも所定値としなくてもよい。すなわち、２点目の燃料温度ｔ２は、１点目の燃料温度ｔ１から一定値以上離れていれば任意の値であるものとし、燃料温度ｔ２および静電容量Ｃ４を検出した後に、（ｔ２－ｔ１）の値に基づいて静電容量の推定値Ｃ２およびＣ３を算出し、その算出された推定値Ｃ２およびＣ３と、検出値Ｃ４とを比較するようにしてもよい。 In this embodiment, the interval Δt between the two fuel temperatures t1 and t2 is a predetermined value, but the interval Δt does not necessarily have to be a predetermined value. That is, it is assumed that the fuel temperature t2 at the second point is an arbitrary value as long as it is a predetermined value or more away from the fuel temperature t1 at the first point, and after detecting the fuel temperature t2 and the capacitance C4, (t2- The estimated values C2 and C3 of the electrostatic capacitance may be calculated based on the value of t1), and the calculated estimated values C2 and C3 may be compared with the detected value C4.
　本実施形態においては、燃料温度ｔ１および静電容量Ｃ１の検出時と、燃料温度ｔ２および静電容量Ｃ４の検出時とで、電極１０，１２近傍の燃料成分濃度に変化がないことが必要である。しかしながら、燃料タンク内の燃料と異なる成分濃度の燃料が給油された場合には、電極１０，１２近傍の燃料成分濃度が途中で変化する可能性がある。このため、誤判定を確実に防止するためには、燃料温度ｔ１および静電容量Ｃ１の検出時と、燃料温度ｔ２および静電容量Ｃ４の検出時とで、電極１０，１２近傍の燃料成分濃度に変化がないことが保証されるような方法をとることが望ましい。そのような方法としては、例えば次のような方法が挙げられる。 In the present embodiment, it is necessary that the fuel component concentration in the vicinity of the electrodes 10 and 12 does not change between the detection of the fuel temperature t1 and the capacitance C1 and the detection of the fuel temperature t2 and the capacitance C4. is there. However, when fuel having a component concentration different from that in the fuel tank is supplied, the fuel component concentration in the vicinity of the electrodes 10 and 12 may change midway. Therefore, in order to prevent erroneous determination reliably, the fuel component concentration in the vicinity of the electrodes 10 and 12 is detected when the fuel temperature t1 and the capacitance C1 are detected and when the fuel temperature t2 and the capacitance C4 are detected. It is desirable to take a method that ensures that there is no change. Examples of such a method include the following method.
　（方法１）燃料タンクの給油口に設けた開閉センサ、あるいは燃料タンク残量計の検出値などに基づいて、給油の有無を判定し、給油が無いと判定されている期間内に、燃料温度ｔ１および静電容量Ｃ１の検出時と、燃料温度ｔ２および静電容量Ｃ４の検出時との双方が入るようにする。 (Method 1) Based on the open / close sensor provided at the fuel filler opening of the fuel tank or the detected value of the fuel tank fuel gauge, the presence or absence of fuel is determined. Both the time t1 and the capacitance C1 are detected and the time when the fuel temperature t2 and the capacitance C4 are detected are entered.
　（方法２）エンジン停止時に燃料温度ｔ１および静電容量Ｃ１を検出し、次回のエンジン始動時に燃料温度ｔ２および静電容量Ｃ４を検出する。エンジン停止時と次回のエンジン始動時とでは、時間が隔たっているので、燃料温度ｔ１と燃料温度ｔ２とは同じにはならない可能性が高い。一方、エンジン停止時と次回のエンジン始動時とで、電極１０，１２近傍の燃料成分濃度には変化がないと考えられる。よって、このような方法が有効である。この方法は、エンジン始動時に判定が終了する点でも有利である。 (Method 2) The fuel temperature t1 and the capacitance C1 are detected when the engine is stopped, and the fuel temperature t2 and the capacitance C4 are detected at the next engine start. There is a high possibility that the fuel temperature t1 and the fuel temperature t2 are not the same because the time is separated between the engine stop and the next engine start. On the other hand, it is considered that there is no change in the fuel component concentration in the vicinity of the electrodes 10 and 12 when the engine is stopped and when the engine is next started. Therefore, such a method is effective. This method is also advantageous in that the determination ends when the engine is started.
　また、本実施形態では、燃料温度ｔ１およびｔ２（＝ｔ１＋Δｔ）の２点において静電容量を検出することによって含有成分がエタノールであるかＥＴＢＥであるかを判定しているが、本発明では、３点以上の燃料温度において静電容量を検出して判定を行うようにしてもよい。 Further, in the present embodiment, it is determined whether the contained component is ethanol or ETBE by detecting capacitance at two points of fuel temperatures t1 and t2 (= t1 + Δt). The determination may be made by detecting the capacitance at three or more fuel temperatures.
　また、本実施形態では、含有成分がエタノールであるかＥＴＢＥであるかを判定しているが、本発明では、比誘電率の温度依存特性が異なる複数の成分であれば、いかなる成分でも判定対象とすることが可能である。例えば、エタノールと水の何れが含有されているかを判定したり、３成分以上のうちの何れが含有されているかを判定したりすることもできる。また、ここで言う「複数の成分」には、劣化度の異なる同種の成分も含まれる。例えば、脂肪酸メチルエステル含有燃料において、含有されている脂肪酸メチルエステル成分の劣化度を本発明により判定することもできる。 In the present embodiment, it is determined whether the contained component is ethanol or ETBE. However, in the present invention, any component can be determined as long as it is a plurality of components having different temperature-dependent characteristics of relative permittivity. Is possible. For example, it can be determined which of ethanol and water is contained, or which of three or more components is contained. The “plurality of components” referred to here includes the same type of components having different degrees of deterioration. For example, the deterioration degree of the fatty acid methyl ester component contained in the fatty acid methyl ester-containing fuel can be determined according to the present invention.
　また、本実施形態では、電極１０，１２間の静電容量を検出するようにしているが、本発明は、燃料の比誘電率あるいはこれと相関する物理量を検出するものであれば、いかなるものにも適用可能である。 In this embodiment, the capacitance between the electrodes 10 and 12 is detected. However, the present invention is not limited as long as it detects the relative dielectric constant of fuel or the physical quantity correlated therewith. It is also applicable to.
　また、上述した実施の形態１においては、静電容量が前記第１の発明における「比誘電率パラメータ」に、温度センサ１４が前記第１の発明における「温度検出手段」に、電極１０，１２が前記第６の発明における「センサ部」に、それぞれ相当している。また、ＥＣＵ５０が、図７および図８のルーチンの処理を実行することにより前記第１の発明における「燃料性状判定手段」が、図７のルーチンの処理を実行することにより前記第３の発明における「推定値算出手段」が、上記ステップ２００，２０２，２０４および２０８の処理を実行することにより前記第３の発明における「成分判定手段」が、それぞれ実現されている。 In the first embodiment described above, the capacitance is the “relative permittivity parameter” in the first invention, the temperature sensor 14 is the “temperature detecting means” in the first invention, and the electrodes 10 and 12 are used. Corresponds to the “sensor part” in the sixth aspect of the invention. Further, when the ECU 50 executes the routine of FIG. 7 and FIG. 8, the “fuel property determination means” in the first aspect of the invention causes the routine of FIG. 7 to execute the routine of the third aspect of the invention. The “estimated value calculating means” implements the “component determination means” according to the third aspect of the present invention by executing the processing of steps 200, 202, 204 and 208 described above.
実施の形態２．
　次に、図９を参照して、本発明の実施の形態２について説明するが、上述した実施の形態１との相違点を中心に説明し、同様の事項については、その説明を簡略化または省略する。 Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG. 9. The description will focus on the differences from the first embodiment described above, and the same matters will be simplified or described. Omitted.
　図９は、本発明の実施の形態２の燃料性状判定装置を示す図である。図９に示すように、本実施形態の燃料性状判定装置は、電極１０，１２の近傍の燃料を加熱可能なヒータ１８を備えている。ヒータ１８への通電はＥＣＵ５０により制御される。本実施形態では、燃料に含有されている成分がエタノールであるかＥＴＢＥであるかを判定する際、１点目の燃料温度ｔ１および静電容量Ｃ１を検出した後、ヒータ１８に通電して電極１０，１２近傍の燃料の温度を上昇させて、２点目の燃料温度ｔ２および静電容量Ｃ４を検出する。このように、本実施形態では、燃料含有成分の判定を行う際、電極１０，１２近傍の燃料温度をｔ１からｔ２へ強制的に上昇させることができるので、燃料温度が自然に変化するのを待つ必要がない。このため、任意のタイミングで、迅速に、含有成分の判定を実行することができる。 FIG. 9 is a diagram showing a fuel property determining apparatus according to Embodiment 2 of the present invention. As shown in FIG. 9, the fuel property determination apparatus of the present embodiment includes a heater 18 that can heat the fuel in the vicinity of the electrodes 10 and 12. Energization of the heater 18 is controlled by the ECU 50. In this embodiment, when determining whether the component contained in the fuel is ethanol or ETBE, after detecting the first fuel temperature t1 and the capacitance C1, the heater 18 is energized and the electrodes The temperature of the fuel in the vicinity of 10 and 12 is increased, and the second fuel temperature t2 and the capacitance C4 are detected. Thus, in this embodiment, when determining the fuel-containing component, the fuel temperature in the vicinity of the electrodes 10 and 12 can be forcibly increased from t1 to t2, so that the fuel temperature naturally changes. There is no need to wait. For this reason, the determination of a contained component can be performed rapidly at arbitrary timings.
実施の形態３．
　次に、図１０を参照して、本発明の実施の形態３について説明するが、上述した実施の形態との相違点を中心に説明し、同様の事項については、その説明を簡略化または省略する。 Embodiment 3 FIG.
Next, the third embodiment of the present invention will be described with reference to FIG. 10. The description will focus on the differences from the above-described embodiment, and the description of the same matters will be simplified or omitted. To do.
　図１０は、本発明の実施の形態３の燃料性状判定装置が備えられたエンジンを示す平面図である。図１０に示すように、本実施形態におけるエンジン２０は、直列４気筒型である。各気筒に設けられた燃料インジェクタ２２は、デリバリパイプ（燃料分配通路）２４に接続されている。燃料タンクから送られてきた燃料は、デリバリパイプ２４を通って、各気筒の燃料インジェクタ２２に分配される。 FIG. 10 is a plan view showing an engine provided with the fuel property determining apparatus according to Embodiment 3 of the present invention. As shown in FIG. 10, the engine 20 in this embodiment is an in-line four-cylinder type. A fuel injector 22 provided in each cylinder is connected to a delivery pipe (fuel distribution passage) 24. The fuel sent from the fuel tank is distributed to the fuel injector 22 of each cylinder through the delivery pipe 24.
　デリバリパイプ２４には、デリバリパイプ２４内の燃料を加熱可能なヒータ２６が設置されている。エンジンＥＣＵ７０は、エンジン２０を冷間始動する場合、ヒータ２６に通電することにより、デリバリパイプ２４内の燃料を加熱する。これにより、燃料インジェクタ２２に供給される燃料の温度を上昇させることができるので、冷間始動時に噴射される燃料の気化不良を防止することができ、始動性やエミッション特性を改善することができる。 The delivery pipe 24 is provided with a heater 26 that can heat the fuel in the delivery pipe 24. When the engine 20 is cold started, the engine ECU 70 energizes the heater 26 to heat the fuel in the delivery pipe 24. Thereby, since the temperature of the fuel supplied to the fuel injector 22 can be raised, it is possible to prevent the vaporization failure of the fuel injected at the cold start, and to improve the startability and emission characteristics. .
　デリバリパイプ２４には、静電容量を検出するための電極と温度センサとを備えた燃料性状センサユニット２８が取り付けられている。燃料性状センサユニット２８の構成は、例えば図１に示す電極１０，１２および温度センサ１４と同様のものとすることができる。本実施形態では、この燃料性状センサユニット２８によって検出される静電容量および燃料温度に基づいて、含有成分がエタノールであるかＥＴＢＥであるかを判定するとともに、その濃度を検出することができる。 A fuel property sensor unit 28 having an electrode for detecting capacitance and a temperature sensor is attached to the delivery pipe 24. The configuration of the fuel property sensor unit 28 may be the same as that of the electrodes 10 and 12 and the temperature sensor 14 shown in FIG. In the present embodiment, based on the capacitance and fuel temperature detected by the fuel property sensor unit 28, it can be determined whether the contained component is ethanol or ETBE, and the concentration can be detected.
　本実施形態では、エンジン２０の冷間始動時にヒータ２６が作動される機会を利用して、含有成分がエタノールであるかＥＴＢＥであるかの判定を実行することができる。すなわち、ヒータ２６による加熱前に１点目の燃料温度ｔ１および静電容量Ｃ１を検出し、ヒータ２６の加熱によってデリバリパイプ２４内の燃料温度が上昇した後、２点目の燃料温度ｔ２および静電容量Ｃ４を検出する。 In the present embodiment, it is possible to determine whether the contained component is ethanol or ETBE by using the opportunity that the heater 26 is activated when the engine 20 is cold started. That is, the first fuel temperature t1 and the capacitance C1 are detected before heating by the heater 26, and after the fuel temperature in the delivery pipe 24 is increased by the heating of the heater 26, the second fuel temperature t2 and static The capacitance C4 is detected.
　本実施形態によれば、エンジン２０の冷間始動時に、含有成分がエタノールであるかＥＴＢＥであるかの判定を終了させることができるので、始動後すぐに、燃料性状に応じた適切なエンジン制御が実行可能となる。また、燃料性状センサユニット２８自体にはヒータが不要であるので、構造を簡素化でき、コストを低減することができる。また、燃料含有成分の判定のためだけにヒータを作動するのではなく、冷間始動時の燃料気化促進のためのヒータ作動の機会を利用して燃料判定を実行するので、電力消費を節減することができる。 According to the present embodiment, when the engine 20 is cold started, it can be determined whether the component is ethanol or ETBE, so that appropriate engine control according to the fuel properties can be performed immediately after starting. Can be executed. Further, since the fuel property sensor unit 28 itself does not require a heater, the structure can be simplified and the cost can be reduced. In addition, the heater is not operated only for determining the fuel-containing component, but the fuel determination is performed by using the opportunity of the heater operation for promoting fuel vaporization at the cold start, so that power consumption is reduced. be able to.
　なお、本実施形態では、燃料性状センサユニット２８をデリバリパイプ２４に設けているが、ヒータ２６の熱が伝わり得る場所であればよいので、必ずしもデリバリパイプ２４自体に燃料性状センサユニット２８を設ける必要はない。例えば、デリバリパイプ２４の入口付近の燃料通路３０に燃料性状センサユニット２８を設置してもよい。 In the present embodiment, the fuel property sensor unit 28 is provided in the delivery pipe 24. However, the fuel property sensor unit 28 is necessarily provided in the delivery pipe 24 itself, as long as it is a place where the heat of the heater 26 can be transmitted. There is no. For example, the fuel property sensor unit 28 may be installed in the fuel passage 30 near the inlet of the delivery pipe 24.
１０，１２　　　　電極
１４　　　　　　温度センサ
１８　　　　　　ヒータ
２０　　　　　　エンジン
２２　　　　　　燃料インジェクタ
２４　　　　　　デリバリパイプ
２６　　　　　　ヒータ
２８　　　　　　燃料性状センサユニット
５０　　　　　　ＥＣＵ
６０　　　　　　燃料通路
７０　　　　　　エンジンＥＣＵ 10, 12 Electrode 14 Temperature sensor 18 Heater 20 Engine 22 Fuel injector 24 Delivery pipe 26 Heater 28 Fuel property sensor unit 50 ECU
60 Fuel passage 70 Engine ECU

Claims (8)

  1. 　内燃機関に供給される燃料の比誘電率またはこれと相関する物理量を比誘電率パラメータとして検出する比誘電率検出手段と、
    　前記比誘電率検出手段の検出対象となる燃料の温度を検出する燃料温度検出手段と、
    　前記燃料温度が異なる複数の点において前記比誘電率パラメータの検出値を取得し、それら各点の前記燃料温度および前記比誘電率パラメータの検出値に基づいて、前記燃料に含有されている成分の性状を判定する燃料性状判定手段と、
    　を備えることを特徴とする内燃機関の燃料性状判定装置。     A dielectric constant detecting means for detecting a dielectric constant of fuel supplied to the internal combustion engine or a physical quantity correlated therewith as a dielectric constant parameter;
    Fuel temperature detection means for detecting the temperature of the fuel to be detected by the relative dielectric constant detection means;
    The detected values of the relative dielectric constant parameters are obtained at a plurality of points having different fuel temperatures, and the components contained in the fuel are determined based on the detected fuel temperatures and detected values of the relative dielectric constant parameters at the respective points. Fuel property determining means for determining properties;
    A fuel property determination apparatus for an internal combustion engine, comprising:
  2. 　前記燃料性状判定手段は、比誘電率の温度依存特性が異なる複数の成分のうちの何れが前記燃料に含有されているかを判定することを特徴とする請求項１記載の内燃機関の燃料性状判定装置。 2. The fuel property determination for an internal combustion engine according to claim 1, wherein the fuel property determination means determines which of a plurality of components having different temperature dependence characteristics of relative permittivity is contained in the fuel. apparatus.
  3. 　前記燃料性状判定手段は、
    　前記複数の点のうちの一の点における前記燃料温度および前記比誘電率パラメータの検出値と、他の点の前記燃料温度とに基づいて、前記他の点の前記比誘電率パラメータの推定値を前記複数の成分毎に算出する推定値算出手段と、
    　前記複数の成分毎の前記推定値のうち、前記他の点の前記比誘電率パラメータの検出値に最も近い推定値に対応する成分が前記燃料に含有されていると判定する成分判定手段と、
    　を含むことを特徴とする請求項２記載の内燃機関の燃料性状判定装置。     The fuel property determining means includes
    Based on the detected value of the fuel temperature and the relative dielectric constant parameter at one point of the plurality of points and the detected fuel temperature at the other point, the estimated value of the relative dielectric constant parameter at the other point An estimated value calculating means for calculating for each of the plurality of components;
    Of the estimated values for each of the plurality of components, component determination means for determining that a component corresponding to an estimated value closest to the detected value of the relative dielectric constant parameter of the other point is contained in the fuel;
    The fuel property determination apparatus for an internal combustion engine according to claim 2, comprising:
  4. 　前記燃料性状判定手段は、前記燃料中の前記成分の濃度が変化していないときに、前記判定を実行することを特徴とする請求項１乃至３の何れか１項記載の内燃機関の燃料性状判定装置。 The fuel property of the internal combustion engine according to any one of claims 1 to 3, wherein the fuel property determination means performs the determination when the concentration of the component in the fuel is not changed. Judgment device.
  5. 　前記燃料性状判定手段は、前記内燃機関が停止されたときの前記燃料温度および前記比誘電率パラメータの検出値と、その次に前記内燃機関が始動されたときの前記燃料温度および前記比誘電率パラメータの検出値とに基づいて前記判定を実行することを特徴とする請求項１乃至４の何れか１項記載の内燃機関の燃料性状判定装置。 The fuel property determination means is configured to detect the fuel temperature and the relative dielectric constant parameter when the internal combustion engine is stopped, and then the fuel temperature and the relative dielectric constant when the internal combustion engine is started. The fuel property determination device for an internal combustion engine according to any one of claims 1 to 4, wherein the determination is performed based on a detected value of a parameter.
  6. 　前記比誘電率検出手段が備えるセンサ部の近傍の燃料を加熱可能なヒータを備え、
    　前記燃料性状判定手段は、前記ヒータによって前記センサ部の近傍の燃料が加熱される際に、前記判定を実行することを特徴とする請求項１乃至５の何れか１項記載の内燃機関の燃料性状判定装置。     A heater capable of heating the fuel in the vicinity of the sensor unit provided in the relative dielectric constant detection means;
    6. The fuel for an internal combustion engine according to claim 1, wherein the fuel property determination unit performs the determination when the fuel in the vicinity of the sensor unit is heated by the heater. Property determination device.
  7. 　前記センサ部は、前記内燃機関の各気筒の燃料インジェクタに燃料を分配する燃料分配通路またはその近傍に配置されており、
    　前記ヒータは、前記燃料分配通路内の燃料を加熱可能であることを特徴とする請求項６記載の内燃機関の燃料性状判定装置。     The sensor unit is disposed in or near a fuel distribution passage for distributing fuel to a fuel injector of each cylinder of the internal combustion engine,
    The fuel property determination device for an internal combustion engine according to claim 6, wherein the heater is capable of heating fuel in the fuel distribution passage.
  8. 　前記燃料性状判定手段は、前記内燃機関の冷間始動時に前記ヒータが作動される機会に、前記判定を実行することを特徴とする請求項７記載の内燃機関の燃料性状判定装置。 8. The fuel property determining apparatus for an internal combustion engine according to claim 7, wherein the fuel property determining means executes the determination at an opportunity when the heater is operated during a cold start of the internal combustion engine.
PCT/JP2010/052365 2010-02-17 2010-02-17 Fuel property determination device for internal combustion engine WO2011101962A1 (en)

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JP2016090304A (en) * 2014-10-31 2016-05-23 株式会社鷺宮製作所 Liquid detector, compressor and air conditioner
FR3101708A1 (en) * 2019-10-07 2021-04-09 Safran Aircraft Engines Method of characterizing a fluid
FR3101707A1 (en) * 2019-10-07 2021-04-09 Safran Aircraft Engines Method of characterizing a fluid

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JP2571465B2 (en) * 1990-10-17 1997-01-16 株式会社ユニシアジェックス Gasoline property identification device
WO2009119087A1 (en) * 2008-03-26 2009-10-01 株式会社デンソー Concentration sensor device and concentration detection method

Patent Citations (2)

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JP2571465B2 (en) * 1990-10-17 1997-01-16 株式会社ユニシアジェックス Gasoline property identification device
WO2009119087A1 (en) * 2008-03-26 2009-10-01 株式会社デンソー Concentration sensor device and concentration detection method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016090304A (en) * 2014-10-31 2016-05-23 株式会社鷺宮製作所 Liquid detector, compressor and air conditioner
FR3101708A1 (en) * 2019-10-07 2021-04-09 Safran Aircraft Engines Method of characterizing a fluid
FR3101707A1 (en) * 2019-10-07 2021-04-09 Safran Aircraft Engines Method of characterizing a fluid

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