JP2011226885A - Fuel property detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel property detector which detects the fuel property with high accuracy.SOLUTION: A fuel property detector according to the present invention comprises: means for detecting the light transmittance of fuel; means for detecting change in the light transmittance of the fuel to temperature change by detecting the light transmittance of the fuel under different temperatures using the light transmittance detecting means; and means for determining the property of the fuel based on the change detected by the light transmittance change detecting means.

Description

  The present invention relates to a fuel property detection device.

  As alternative fuels for automobile fuel, biomass-derived components such as ethanol and methyl ester are beginning to spread. Biomass-derived components are often used by mixing with conventional fuels such as gasoline and light oil. Fuel characteristics such as the theoretical air-fuel ratio value, calorific value, and vaporization characteristics vary depending on the mixing ratio of the biomass-derived component and the conventional fuel. For this reason, in order to control the engine appropriately, it is necessary to accurately detect the mixing ratio (concentration) of biomass-derived components and perform engine control according to the mixing ratio.

  As a method for detecting a fuel property such as a mixing ratio of a biomass-derived component and a conventional fuel, a technique for determining a fuel property based on a measured value of light transmittance is known (see, for example, Patent Document 1). That is, in this prior art, the mixing ratio is detected by utilizing the fact that the light transmittance of the two components differs and the light transmittance of the fuel changes according to the mixing ratio of the two components.

JP 2008-286531 A JP 2008-107098 A

  However, the above-described conventional technique has a problem that it is difficult to accurately detect the mixing ratio when the difference in light transmittance between the mixed components is small.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a fuel property detection device capable of detecting a fuel property with high accuracy.

In order to achieve the above object, a first invention is a fuel property detection device,
A light transmittance detecting means for detecting the light transmittance of the fuel;
A light transmittance change detecting means for detecting a change in the light transmittance of the fuel with respect to a temperature change by detecting the light transmittance of the fuel by the light transmittance detecting means at a plurality of different temperatures;
Fuel property determination means for determining the property of the fuel based on the change detected by the light transmittance change detection means;
It is characterized by providing.

The second invention is the first invention, wherein
The fuel contains a first component and a second component whose light transmittance changes with temperature, which is larger than the first component,
The fuel property determining means determines a mixing ratio between the first component and the second component.

The third invention is the first or second invention, wherein
A temperature adjusting means for adjusting the temperature of the fuel to a plurality of different temperatures is provided.

  According to the first invention, the property of the fuel can be detected with high accuracy by utilizing the characteristic that the light transmittance varies with temperature.

  According to the second aspect of the present invention, it is possible to detect with high accuracy the fuel mixture ratio in which components having different rates of change in light transmittance depending on temperature are mixed.

  According to the third invention, the temperature of the fuel to be detected can be forcibly adjusted, so that the fuel property can be detected quickly and reliably when necessary.

It is a figure which shows Embodiment 1 of the fuel property detection apparatus of this invention. Illustrates different temperatures T ₁ and T ₂ in the substance A, the wavelength characteristics of light transmittance of the material B and the detection object. It is a figure which shows the calibration data for calculating a density | concentration based on the variation | change_quantity of the light transmittance by temperature. It is a flowchart of the routine performed in Embodiment 1 of the present invention.

  FIG. 1 is a diagram showing a first embodiment of the fuel property detection device of the present invention. The fuel property detection device of the present embodiment detects the property of fuel supplied to an internal combustion engine (not shown) mounted on a vehicle or the like. As shown in FIG. 1, the fuel property detection device includes a housing 10. The housing 10 is installed in the middle of a fuel supply path that sends fuel from a fuel tank to an internal combustion engine, for example. Or you may install the housing | casing 10 in a fuel tank. A fuel passage 12 through which fuel passes is formed inside the housing 10. The fuel passage 12 is filled with fuel. The housing 10 is provided with a light emitting device 14 and a light receiving device 16 for detecting the light transmittance of the fuel. The light emitting device 14 and the light receiving device 16 are arranged to face each other with the fuel passage 12 interposed therebetween. The fuel passage 12 and the light emitting device 14 are separated by a light guide member 18 made of a transparent material. The light guide member 18 has a convex shape, and is installed in a state in which a part of the convex portion protrudes into the fuel passage 12. A seal member 20 is installed between the housing 10 and the light guide member 18 to ensure liquid tightness. The fuel passage 12 and the light receiving device 16 are separated by a disk-like window member 22 made of a transparent material. Between the housing 10 and the window member 22, a seal member 24 for securing liquid tightness is installed.

  The housing 10 is further provided with a temperature adjusting device 26 that adjusts the temperature of the fuel in the fuel passage 12 and a temperature sensor 28 that detects the temperature of the fuel in the fuel passage 12. The temperature adjustment device 26 includes a heater that can raise the fuel temperature in the fuel passage 12. Further, when it is necessary to lower the temperature of the fuel in the fuel passage 12, the temperature adjusting device 26 can be configured to cool the fuel by using, for example, a Peltier element.

  The fuel property detection device further includes an ECU (Electronic Control Unit) 50. The light emitting device 14, the light receiving device 16, the temperature adjusting device 26, and the temperature sensor 28 are each electrically connected to the ECU 50.

  The light emitted from the light emitting device 14 passes through the light guide member 18 and is irradiated to the fuel filled between the light guide member 18 and the window member 22. The light transmitted through the fuel between the light guide member 18 and the window member 22 passes through the window member 22 and is received by the light receiving device 16. The light receiving device 16 photoelectrically converts the received light and outputs an output corresponding to the light amount. As the light transmittance of the fuel in the fuel passage 12 is higher, the amount of light incident on the light receiving device 16 is increased, and the output of the light receiving device 16 is increased. Therefore, the ECU 50 can detect the light transmittance of the fuel based on the output of the light receiving device 16.

Next, a fuel property detection method according to the present embodiment will be described with reference to FIG. Below, the case where the mixing ratio (here, it is set as the density | concentration of the substance B) of the fuel with which 2 types of substances (it is set as the substance A and the substance B) were mixed is demonstrated. FIG. 2 is a diagram illustrating wavelength characteristics of light transmittances of the substances A, B, and the detection target at different temperatures T ₁ and T ₂ (T ₁ ≠ T ₂ ).

Some materials have light transmittance (particularly, light transmittance in a specific wavelength band) that varies with temperature. The amount of change in light transmittance with respect to temperature changes varies depending on the material. Some materials have a large amount of change, and some materials hardly change. The substance A represents a substance having a small temperature dependence of light transmittance, and the substance B represents a substance having a large temperature dependence of light transmittance. In FIG. 2, the light transmittance when the substance A is 100% (hereinafter, simply referred to as “light transmittance of the substance A”) and the light transmittance when the substance B is 100% (hereinafter, simply “ (Referred to as “light transmittance of substance B”). The light transmittance of the substance A is substantially the same at both the temperature T ₁ and the temperature T ₂ because the change with temperature is small. On the other hand, the light transmittance of the substance B varies greatly with temperature. In the following description, let c be the difference between the light transmittance of the substance B at the temperature T ₁ and the light transmittance of the substance B at the temperature T ₂ .

FIG. 2 further shows the light transmittance at temperatures T ₁ and T ₂ of the fuel to be detected, that is, the mixture of substance A and substance B (hereinafter referred to as “detection object”). . In the following description, let b be the difference between the light transmittance of the detection object at the temperature T ₁ and the light transmittance of the detection object at the temperature T ₂ . Further, a is a difference between the light transmittance of the substance A at the temperatures T ₁ and T ₂ and the light transmittance of the detection target at the temperature T ₁ .

In the fuel property detection device of the present embodiment, the temperature adjustment device 26 adjusts the temperature of the fuel, thereby measuring the light transmittance at the temperature T _{1 and} the light transmittance at the temperature T ₂ . Then, the concentration of the substance B is calculated based on the difference b between the two. Thereby, the density | concentration of the substance B can be calculated | required more correctly. The reason will be described below.

If the concentration of the substance B in the detection target is obtained based only on the light transmittance measured at the temperature T ₁ , the measured value of the light transmittance of the detection target at the temperature T ₁ is substantially The difference a from the light transmittance (value stored in advance) of the substance A at the temperature T ₁ is obtained, and the concentration of the substance B is calculated based on the value of a. However, when the concentration of the substance B is low, the light transmittance of the object to be detected is close to the light transmittance of the substance A, so the value of a which is the difference between the two becomes small. For this reason, it becomes easy to receive the influence of an error, and it becomes difficult to detect the density | concentration of the substance B accurately.

In such a case, by changing the temperature of the object to be detected T _2, by utilizing the change of light transmittance of the material B, it is possible to accurately detect the concentration of a substance B. When the temperature changes from T ₁ to T ₂ , the light transmittance of the substance B greatly changes (decreases). This amount of change corresponds to c. Since this influence also appears in the detection target that is a mixture, when the temperature changes from T ₁ to T ₂ , the light transmittance of the detection target also changes (decreases). This amount of change corresponds to b. If the detection target is composed of 100% substance B, the change amount b is equal to the change amount c. Conversely, if the detection target is composed of 100% substance A, the amount of change b should be zero. Therefore, the relationship between the change amount b and the concentration of the substance B is conceptually as shown in FIG.

Therefore, calibration data as shown in FIG. 3 is created and stored in the ECU 50 in advance, and the light transmittance at the temperature T _{1 and} the light transmittance at the temperature T ₂ are measured for the fuel that is the detection target. And the density | concentration of the substance B can be calculated | required accurately by calculating | requiring the difference b of both, and collating with calibration data.

FIG. 4 is a flowchart of a routine executed by the ECU 50 in the present embodiment in order to detect the fuel property based on the above method. According to the routine shown in FIG. 4, first, a process of measuring the light transmittance of the fuel at a predetermined temperature T ₁ is executed (step 100). In this process, first, the temperature adjusting device 26 is operated to change the fuel temperature in the fuel passage 12 to T ₁ . When the fuel temperature detected by the temperature sensor 28 reaches T ₁ , the light transmittance is measured using the light emitting device 14 and the light receiving device 16.

Next, a process of measuring the light transmittance of the fuel at a predetermined temperature T ₂ different from the temperature T ₁ is executed (step 102). In the present embodiment, in this process, the fuel temperature of the fuel passage 12 actuates the temperature control device 26 so as to change to T _2. When the fuel temperature detected by the temperature sensor 28 reaches T ₂ , the light transmittance is measured using the light emitting device 14 and the light receiving device 16.

Subsequently, a difference b between the measured value of the light transmittance at the temperature T ₁ obtained in the step 100 and the measured value of the light transmittance at the temperature T ₂ obtained in the step 102 is calculated ( Step 104). Then, the concentration of the substance B is calculated by collating the calculated value b with calibration data stored in advance as shown in FIG. 3 (step 106).

  According to the fuel property detection device of the present embodiment as described above, it is possible to accurately detect the mixture ratio (concentration) of the contained component by utilizing the characteristic that the light transmittance of the contained component varies with temperature. it can.

  In order to further improve the detection accuracy, the light-emitting device 14 and the light-receiving device 16 are configured so that the light transmittance is detected using light in a predetermined wavelength band in which a change in the light transmittance with respect to a temperature change greatly appears. It is desirable to set specifications. That is, a light-emitting element having an emission wavelength that matches the predetermined wavelength band is used as the light-emitting device 14, or the emission wavelength of the light-emitting device 14 is set using the optical filter that selectively transmits light in the predetermined wavelength band. It is desirable to match the predetermined wavelength band. Alternatively, the same effect can be obtained by using the light receiving device 16 that selectively has high sensitivity to light in the predetermined wavelength band.

  In the present invention, light for measuring light transmittance (light emitted from the light emitting device 14 and received by the light receiving device 16) is not limited to the visible light region, but may be light in the infrared region or the ultraviolet region. Good.

In the present embodiment, the change in the light transmittance of the substance A between the temperatures T ₁ and T ₂ has been described as being substantially zero. However, the scope of the present invention is limited to such a case. However, the present invention can be applied as long as there is a magnitude relationship in the amount of change in light transmittance with respect to temperature change between the contained components. In addition, the component to be detected is not limited to the component originally contained in the fuel. For example, the fuel may absorb moisture in the air, or moisture may be generated in the fuel due to deterioration of biomass-derived components. Water has a characteristic that the light transmittance in a specific wavelength band varies greatly with temperature. For this reason, according to the fuel property detection device of the present invention, the moisture content of the fuel can be detected with high accuracy by detecting the change of the light transmittance in the specific wavelength band due to the temperature.

  Further, the fuel property to be detected by the fuel property detection device of the present invention is not limited to the mixing ratio (concentration) of each component. For example, rapeseed oil has a constant light transmittance regardless of temperature when it is new, but exhibits a characteristic that the light transmittance varies with temperature when it is oxidized and deteriorated. Therefore, it is also possible to detect oxidative deterioration of a fuel containing a component exhibiting similar characteristics such as rapeseed oil by the fuel property detection device of the present invention. That is, if no change in light transmittance with respect to temperature change is observed, it is determined that the fuel has not been oxidized and deteriorated. If the amount of change in light transmittance with respect to temperature change exceeds the reference value, the fuel has oxidized and deteriorated. Can be determined.

Further, in the present embodiment, the light transmittance at the temperatures T ₁ and T ₂ is measured by forcibly changing the temperature of the fuel by the temperature adjusting device 26, but heat transfer from the outside (for example, If the fuel temperature in the fuel passage 12 can be expected to change within the range including the temperatures T ₁ and T _{2 due} to heat transfer from the internal combustion engine, the exhaust pipe, etc., the temperature control device 26 is not necessary. In such a case, the light transmittance may be measured in accordance with the timing when the fuel temperature detected by the temperature sensor 28 becomes T ₁ and the timing when it becomes T ₂ . Further, when the specific temperatures T ₁ and T ₂ for measuring the light transmittance are not determined, and only the light transmittance needs to be detected depending on the temperature, the temperature sensor 28 is also unnecessary.

In this embodiment, the specific temperature at which the light transmittance is measured is described as two points T ₁ and T _2. However, in the present invention, the light transmittance is measured at three or more different temperatures. The fuel properties may be determined based on the change in the light transmittance.

  In the first embodiment described above, the light emitting device 14, the light receiving device 16, and the ECU 50 are the “light transmittance detecting means” in the first invention, and the substance A is the “first component” in the second invention. The substance B corresponds to the “second component” in the second invention. Further, when the ECU 50 executes the processing of the above steps 100 to 104, the “light transmittance change detecting means” in the first invention executes the processing of the above step 106, so that “ “Fuel property determining means” is realized.

DESCRIPTION OF SYMBOLS 10 Housing | casing 12 Fuel passage 14 Light-emitting device 16 Light-receiving device 18 Light guide member 22 Window member 26 Temperature control apparatus 50 ECU

Claims (3)

A light transmittance detecting means for detecting the light transmittance of the fuel;
A light transmittance change detecting means for detecting a change in the light transmittance of the fuel with respect to a temperature change by detecting the light transmittance of the fuel by the light transmittance detecting means at a plurality of different temperatures;
Fuel property determination means for determining the property of the fuel based on the change detected by the light transmittance change detection means;
A fuel property detection device comprising: The fuel contains a first component and a second component whose light transmittance changes with temperature, which is larger than the first component,
The fuel property detection device according to claim 1, wherein the fuel property determination unit determines a mixing ratio between the first component and the second component.   The fuel property detection device according to claim 1, further comprising temperature adjusting means for adjusting the temperature of the fuel to the plurality of different temperatures.

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