JPH0599878A - Determining apparatus for property of alcohol blended fuel - Google Patents

Abstract

PURPOSE:To highly accurately detect individual alcohol concentration in alcohol blended fuel wherein two kinds of alcohol (methanol, ethanol) are blended. CONSTITUTION:Reference voltages V01, V02 from oscillators 2, 3 having different peak height values are output to each capacitance sensor 1. From a difference in electric field intensity generated between respective electrodes 1A of each capacitance sensor 1, intensity of dielectric polarization of alcohol blended fuel between the respective electrodes 1A is different and capacitance C is different. Two characteristic maps are created from the difference in capacitance, blend lines are calculated from the respective characteristic maps, and by obtaining their intersection, ethanol concentration and methanol concentration can be individually detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a property determination device for alcohol mixed fuel, which is applied to a fuel injection control device for an engine using a mixed fuel of methanol and ethanol.

[0002]

2. Description of the Related Art In recent years, due to demands for environmental protection, energy saving, etc., attention has been paid to an alcohol-mixed fuel prepared by mixing alcohol such as methanol with gasoline as fuel for automobiles. However, since the theoretical air-fuel ratio of this alcohol-mixed fuel differs depending on the alcohol concentration, it is necessary to install an alcohol concentration measuring device in the fuel pipe to measure the alcohol concentration in the fuel and adjust the fuel injection amount accordingly.

The air-fuel ratio A / F of genuine gasoline is 1
Although it is 4.7, it is necessary to control the air-fuel ratio A / F to be 6.5 when methanol having an alcohol concentration of 100% is used. The air-fuel ratio A / F will differ about twice.

Therefore, when alcohol mixed fuel is used, an alcohol concentration measuring device called an alcohol sensor is provided, an output voltage corresponding to the alcohol concentration is generated, and the fuel injection amount is calculated based on the output voltage value. I'm doing it.

As this type of alcohol concentration measuring device, a capacitance type alcohol concentration measuring device for detecting the alcohol concentration from the dielectric constants of gasoline and alcohol is known.

[0006]

However, in the above-mentioned prior art, when the alcohol mixed in the gasoline is a single alcohol, excellent detection can be achieved.
There are the following problems.

First, two types of alcohol, which are mixed in gasoline, are typically considered: ethanol and methanol. There are cases where they are mixed alone and cases where they are mixed and mixed. .. The components and relative permittivity of ethanol and methanol (ethanol 32, methanol 2
4. Since gasoline 2) is different, it is necessary to individually detect the ethanol concentration and the methanol concentration when mixed and mixed. However, the conventional alcohol concentration measuring device cannot detect the mixing ratios of gasoline, ethanol, and methanol in the alcohol-mixed gasoline.

Second, even when ethanol or methanol is mixed alone, the same alcohol is not always mixed, and ethanol and methanol have different influences on the capacitance due to the difference in relative dielectric constant. Therefore, a single alcohol concentration measuring device cannot be used.

Thirdly, when mixed gasoline in which two kinds of alcohol may be mixed is used in an engine of an automobile or the like, it is impossible to perform appropriate fuel injection amount control and ignition timing control for the engine. ..

The present invention has been made in view of the above-described problems of the prior art, and the present invention can individually detect the alcohol concentration of each alcohol-blended fuel in which two kinds of alcohol may be mixed. An object of the present invention is to provide a property determination device for alcohol-mixed fuel capable of performing appropriate fuel injection amount control and ignition timing control of the engine.

[0011]

In order to solve the above-mentioned problems, the property determination device for an alcohol-mixed fuel according to the first aspect of the present invention is one alcohol and another alcohol or both one alcohol and another alcohol are mixed. Capacitance sensor provided in the mixed alcohol mixed fuel, and capacitance or relative permittivity is calculated by a detection signal from the capacitance sensor when a first voltage is applied to the capacitance sensor. And a second capacitance calculation means for controlling the capacitance sensor.
Second capacitance calculation means for calculating the capacitance or relative permittivity by the detection signal from the capacitance sensor when the voltage is applied and the known mixing ratio of one alcohol and another alcohol is changed. In this case, the first storage means for storing the rate of change in capacitance or relative permittivity calculated by the first capacitance calculation means, and one known alcohol and another alcohol When the mixing ratio is variable,
Second storage means for storing the rate of change in capacitance or relative permittivity calculated by the second capacitance calculation means;
A first mixture for calculating an electrostatic capacitance or a relative permittivity of an unknown alcohol mixed fuel using a first capacity calculating means, and calculating a mixing line of one alcohol and another alcohol from the first storage means. The capacitance or the relative permittivity is calculated using the line calculation means and the second capacity calculation means for the unknown alcohol mixed fuel, and the mixed line of one alcohol and another alcohol is calculated from the second storage means. The intersection point between the second mixing line calculating means and the mixing line by the first and second mixing line calculating means is obtained, and from this intersection point, one alcohol concentration in the alcohol-mixed fuel, another alcohol concentration, or one alcohol And an individual concentration calculating means for calculating the individual concentration of another alcohol.

Further, an alcohol mixed fuel property determining device according to the second invention is provided in an alcohol mixed fuel in which both one alcohol and another alcohol or both one alcohol and another alcohol are mixed, and an electrode constant is provided. A first and a second capacitance sensor having different values and a first capacitance sensor which calculates a capacitance or a relative dielectric constant by a detection signal from the capacitance sensor when a voltage is applied to the first capacitance sensor. 1
Known capacitance calculating means, and second capacitance calculating means for calculating capacitance or relative permittivity by a detection signal from the capacitance sensor when a voltage is applied to the second capacitance sensor. A first memory that stores the rate of change in capacitance or relative permittivity calculated by the first capacitance calculation means when the mixing ratio of one alcohol and another alcohol is variable. When the means and the mixing ratio of the known one alcohol and the other alcohol are variable, the second
Second storage means for storing the rate of change in the electrostatic capacity or relative permittivity calculated by the electrostatic capacity calculation means, and for the unknown alcohol mixed fuel, the electrostatic capacity or First mixing line calculating means for calculating a relative permittivity and calculating a mixing line of one alcohol and another alcohol from the first storing means, and second capacity calculating means for an unknown alcohol mixed fuel are used. Second mixed line calculation means for calculating a mixed line of one alcohol and another alcohol from the second storage means by calculating capacitance or relative permittivity by the second storage means, and the first and second mixed lines. From the intersection point of the mixing line by the calculating means, from this intersection point, one alcohol concentration in the alcohol-mixed fuel, another alcohol concentration, or an individual concentration calculating means for calculating the individual concentration of one alcohol and another alcohol There in that form.

[0013]

With the above structure, the first mixing line is calculated from the electrostatic capacity or relative permittivity of the unknown alcohol mixed fuel detected by the first capacity calculating means, and detected by the second capacity calculating means. A second mixing line is calculated from the capacitance or relative permittivity of the unknown alcohol mixed fuel. Then, by obtaining the intersection of the first and second mixed lines,
The concentration of each of the two alcohols in the alcohol-blended fuel can be detected individually, or the concentration of a single alcohol can be detected.

[0014]

Embodiments of the present invention will be described below with reference to FIGS.

First, a description will be given of a device for discriminating properties of alcohol-mixed fuel according to a first embodiment of the present invention with reference to FIGS. 1 and 7.

In the figure, reference numerals 1 and 1 denote coaxial sensors (see FIG. 10 or FIG. 11) or parallel plate shapes, which are formed in the same shape and have the same electrode constant. The capacitance sensor 1 has its electrodes 1A, 1
A, ... Are inserted into the alcohol-blended gasoline.

Here, the alcohol mixed gasoline is constituted by mixing ethanol as one alcohol and methanol as another alcohol into gasoline as an alcohol mixed fuel.

Reference numerals 2 and 3 denote oscillators. The oscillators 2 and 3 are respectively connected between the capacitance sensors 1 and the ground so as to output different peak values at the same frequency f. , For example, having an attenuator of -39dbm, -65dbm and adjusting reference voltage V01, respectively.
V02 is generated toward each of the capacitance sensors 1. Here, the oscillation frequencies of the oscillators 2 and 3 are 1 to
It is set to 50 MHz, preferably 10 to 40 MHz. Then, different electric field strengths are generated between the respective electrodes 1A of the respective capacitance sensors 1 by the change of the peak value, and the strength of the dielectric polarization in the alcohol-mixed gasoline between the respective electrodes 1A is made variable, Capacitances C1 and C of the capacitance sensor 1
Let 2 be a different value.

Reference numerals 4 and 4 denote differentiating circuits connected to the output side of each capacitance sensor 1. Each differentiating circuit 4 is connected between an operational amplifier 5 and an output terminal and an inverting terminal of the operational amplifier 5. The negative feedback resistor 6 is connected to the ground, and the non-inverting terminal of the operational amplifier 5 is connected to the ground.

Reference numeral 7 denotes an arithmetic unit composed of a RAM, a ROM and the like as a microcomputer. The arithmetic unit 7 is an input / output control circuit 8, a processing circuit 9 and a storage circuit 10.
The input / output control circuit 8 has an input side to which the output voltages V1 and V2 of the respective capacitance sensors 1 are inputted via the differentiating circuits 4 so that the operational amplifiers 5 of the respective operational amplifiers 5 are inputted. It is connected to the output terminals and also connected to the reference signal lines 11 and 12 so that the reference outputs V01 and V02 from the oscillators 2 and 3 are input. For example, unknown ethanol EX and methanol concentration MX are connected to the output side. The display 13 for displaying is connected. In addition, in the memory circuit 10, FIG.
The processing programs and the like shown in FIG. 6 are stored therein, and the storage area 10A stores characteristic maps I and II as shown in FIGS.

Here, the electrostatic capacitances C1 and C2 in the alcohol-blended gasoline are detected by detecting the reference voltage V01 and the output voltage V1.
And the change amount of the imaginary part of the reference voltage V02 and the output voltage V2 (steps 2 and 5 described later). The oscillator 3, the electrostatic capacitance sensor 1, the reference voltage V01 and the output voltage V1 are calculated to detect the electrostatic capacitance C1 to form a first electrostatic capacitance calculating means. Capacitance sensor 1 and reference voltage V
The second electrostatic capacitance calculating means is configured by detecting the electrostatic capacitance C2 by the calculation of 02 and the output voltage V2.

Further, the characteristic map I shows various known alcohol mixtures in which the concentrations of gasoline and ethanol (for example, 0%, 15%, ...) And the concentrations of gasoline and methanol (for example, 0%, 15%, ...) Are fixed. Gasoline is created by the electrostatic capacity C1 calculated by the first electrostatic capacity calculating means, and the change in methanol concentration M is plotted on the basis of the ethanol concentration E on the horizontal axis and the electrostatic capacitance on the vertical axis. is there.

On the other hand, the characteristic map II shows various known alcohol mixtures in which the concentrations of gasoline and ethanol (for example, 0%, 15%, ...) And the concentrations of gasoline and methanol (for example, 0%, 15%, ...) Are fixed. Gasoline is created by the second electrostatic capacity calculating means by the calculated electrostatic capacity C2, and the change in the methanol concentration M is plotted on the basis of the ethanol concentration E on the horizontal axis and the electrostatic capacitance on the vertical axis. is there.

The storage area 10A of the storage circuit 10
The storage of the characteristic map I in the inside becomes the first storage means, and the storage of the characteristic map II in the storage area 10A of the storage circuit 10 becomes the second storage means.

Next, the detection of the ethanol concentration EX and the methanol concentration MX of an unknown alcohol-blended gasoline will be described with reference to the programs shown in FIGS. 4 to 6. For the sake of convenience, the unknown methanol concentration and ethanol concentration are defined as the methanol mixture concentration M and the ethanol mixture concentration E, respectively, and the known ethanol concentration E, the methanol concentration M, and the ethanol concentration EX of the unknown alcohol mixture gasoline EX.
, Methanol concentration MX.

First, in step 1, the reference voltage V01 is read through the reference signal line 11 and the output voltage V1 is read.
Is read from the differentiating circuit 4, and the electrostatic capacitance C01 is calculated from the amount of change in the imaginary part due to the waveforms of the reference voltage V01 and the output voltage V1 read in step 2 (first capacitance calculating means).

In step 3, the ethanol mixture concentrations E10, E11, ... Corresponding to the methanol mixture concentrations M0, M1, ... In the capacitance C01 are calculated from the characteristic map I (see characteristic map I in FIG. 2), and this methanol is calculated. Mixed concentration M0
, M1, ... And mixed ethanol concentrations E10, E11, ... are stored in the storage area 10A of the storage circuit 10.

In step 4, as in step 1, the reference voltage V02 is read through the reference signal line 12, the output voltage V2 is read from one of the differentiating circuits 4, and the reference voltage V02 and the output voltage read in step 5 are read. The electrostatic capacitance C02 is calculated from the amount of change in the imaginary part due to the waveform of V2 (second capacitance calculating means).

In step 6, the ethanol mixture concentrations E20, E21, ... Corresponding to the methanol mixture concentrations M0, M1, ... In the capacitance C02 are calculated from the characteristic map II (see the characteristic map II in FIG. 3). Mixed concentration M0
, M1, ... And ethanol mixed concentrations E20, E21, ... are stored in the storage area 10A of the storage circuit 10.

In step 7, as shown in FIG. 7, the ethanol mixing concentrations E10, E11, ... Corresponding to the methanol mixing concentrations M0, M1, ... Detected by the first capacity calculating means stored in the storage area 10A are used. A mixing line L1 is calculated on a graph in which the horizontal axis indicates the methanol mixing concentration M and the vertical axis indicates the ethanol mixing concentration E (first mixing line calculating means). Further, the mixing line L2 is calculated on the FIG. 7 by the ethanol mixing concentrations E20, E21, ... Corresponding to the methanol mixing concentrations M0, M1, ... Detected by the second capacity calculating means (second mixing line calculating means). ). And the mixed line L1,
The intersection of L2 is calculated, and the unknown ethanol concentration EX and methanol concentration MX are calculated (individual concentration calculation means).

Then, in step 8, the ethanol concentration E of the unknown alcohol-blended gasoline detected in step 7
The X and methanol concentrations MX are displayed on the display unit 13.

As described above, in the alcohol-mixed-fuel property determination apparatus according to this embodiment, the ethanol concentration EX and the methanol concentration MX can be reliably detected even when ethanol and methanol are mixed in the alcohol-mixed gasoline. .. Further, even when ethanol or methanol is mixed in gasoline alone, the respective ethanol concentration EX or methanol concentration MX can be detected by this alcohol mixed fuel property determination device.

Therefore, if each capacitance sensor 1 is provided in the middle of the fuel supply pipe of an engine of an automobile or the like, and the arithmetic unit 7 is built in the control unit, any mixed concentration of alcohol-mixed gasoline of ethanol and methanol can be obtained. Even in this case, it is possible to accurately detect, and it is possible to control an appropriate fuel injection amount and ignition timing. And the driving performance of the vehicle can be improved.

Next, a second embodiment of the present invention will be described with reference to FIG. 8. The feature of this embodiment is that the capacitance sensor is
The voltage supplied to the electrostatic capacitance sensor is added after adding the voltages having different frequencies and peak values with an adder, and the output from the electrostatic capacitance sensor is distributed by two band pass filters. Then, it is configured to output to the arithmetic unit. The same components as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numerals 21 and 22 denote oscillators, and the oscillators 21 and 22 have different frequencies f1 and f2 (f1> f2).
To oscillate. These oscillators 21 and 22 have respective oscillation frequencies f1 and f2 as in the oscillators 2 and 3 of the first embodiment.
Is set to 1 to 50 MHz.

Reference numerals 23 and 24 denote attenuators connected to the output sides of the oscillators 21 and 22. The attenuators 23 and 24 are attenuated to -39dbm and -65dbm, respectively, and the reference voltage V
It outputs 01 and V02.

Reference numeral 25 denotes an adder, which adds the reference voltages V01 and V02 from the attenuators 23 and 24,
Output to the capacitance sensor 1.

Reference numerals 26 and 27 denote bandpass filters connected between the output terminal of the operational amplifier 5 and the input / output control circuit 8 of the arithmetic unit 7. The bandpass filters 26 and 27 are provided.
Distributes the output voltage from the capacitance sensor 1 to the respective frequencies f1 and f2, and outputs it as the output voltages V1 and V2 to the input / output control circuit 8 of the arithmetic unit 7.

28 and 29 are reference signal lines,
One end of each of the reference signal lines 28 and 29 is the attenuator 2
The other ends of the output sides of 3, 24 are connected to the input / output control circuit 8, and the reference voltages V01, V02 are output to the arithmetic unit 7 through the reference signal lines 28, 29.

In this embodiment having such a configuration, the reference voltages V01 and V02 having the frequencies f1 and f2 are added by the adder 25 and supplied to the capacitance sensor 1 so that the electrodes 1A are connected to each other. It is possible to change the generated electric field strength for each frequency, change the dielectric polarization strength of the alcohol-blended gasoline, and change the electrostatic capacity for each frequency.
Then, as described in the first embodiment, the characteristic maps as shown in FIGS.
The unknown ethanol concentration EX and methanol concentration MX can be detected by the programs shown in FIGS. 4 to 6 and the individual concentration calculating means shown in FIG.

In this embodiment having the above-mentioned structure, only one capacitance sensor 1 is used as in the first embodiment, and the rest of the structure can be formed by an electronic circuit. The cost can be reduced as compared with the first embodiment, and the variations in the characteristics of the respective sensors 1 caused by using the two capacitance sensors 1 can be suppressed to enable highly accurate detection.

In the second embodiment, each oscillator 2
Although different attenuators 23 and 24 are respectively connected to 1 and 22 to attenuate the peak values of the oscillators 21 and 22, respectively, they are different like the oscillators 2 and 3 of the first embodiment. An oscillator having an attenuator may be used.

Furthermore, a third embodiment of the present invention will be described with reference to FIGS. 9 to 11. The feature of this embodiment is that two coaxial cylindrical capacitance sensors having different electrode constants are provided.
A reference voltage having the same frequency and the same peak value is supplied to each capacitance sensor. The same components as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, 31 indicates an oscillator, and the oscillator 31
Outputs a reference voltage V01 having a frequency f to capacitance sensors 32 and 42 described later. Here, the oscillator 31 also has an oscillation frequency of 1 to 50 MHz, while the reference voltage V01 becomes -39 dbm by the attenuator.

Reference numeral 32 denotes a first capacitance sensor, and the first capacitance sensor 32 is formed in a coaxial cylindrical shape having a casing 36 and a center electrode 37, which will be described later, as shown in FIG.

Here, the first capacitance sensor 32 is formed by joining cylindrical pipe members 33 and 34 into a substantially L-shape or a substantially T-shape, and one end side of the pipe member 33 is made of an insulating material. It has a tubular casing 36 closed by a plug 35, and the pipe member 3 of the casing 36.
3, 34 are formed of conductive iron pipes plated with nickel or the like. The other end of the pipe member 33 has an inlet 33A for alcohol-mixed gasoline.
The tip end side of the pipe member 34 serves as an outlet 34A, the inlet 33A and the outlet 34A are connected in the middle of a fuel pipe (not shown), and the alcohol mixed gasoline flows in the casing 36 in the direction of the arrow. ..

37 is the plug 3 from one end of the pipe member 33.
5 shows a rod-shaped center electrode that axially protrudes into the pipe member 33 through 5 and constitutes a coaxial cylindrical counter electrode together with the pipe member 33. One end of the center electrode 37 is integrally supported with the pipe member 33. It is supported by the member 38.

The support member 38 is the pipe member 33.
An insulating fitting member 40 fitted to one end side of the fitting member via a conductive tubular body 39, and a nut protruding from the outer end surface of the fitting member 40 in a radial direction outward and extending to the one end side of the center electrode 37. 41
The fitting member 4 via the washer 42 by screwing
It is composed of one side terminal 43 on the side of the center electrode 37 that is fastened to 0, and another side terminal 44 that is sandwiched between the tubular body 39 and the fitting member 40 and that projects radially outward. The other-side terminal 44 is connected to the pipe member 33 via a conductive tubular body 39. The one-side electrode 43 is connected to the output side of the oscillator 31, and the other-side electrode 44 is connected to the one differentiating circuit 4.

Here, since the center electrode 37 extends in the pipe member 33 in the axial direction and constitutes a coaxial cylindrical counter electrode together with the pipe member 33, the center electrode 37 and the pipe are connected via the terminals 43 and 44. By externally applying a voltage between the member 33 and the member 33, the central electrode 37 and the pipe member 33
The electrostatic capacitance C1 of the alcohol-mixed gasoline flowing in the direction of the arrow between and is detected by the following formula 1.

[0050]

[Equation 1] a1: radius of the center electrode b1: radius of the pipe member d: displacement of the center electrode with respect to the center axis of the inflow pipe K1: electrode constant of the first capacitance sensor εr: relative permittivity of alcohol mixed fuel ε0: vacuum dielectric Rate C0: Inherent capacity of detector

Reference numeral 45 denotes a second electrostatic capacity sensor which is constructed in substantially the same manner as the first electrostatic capacity sensor 32.
A dash (') is attached to the same component member as the electrostatic capacitance sensor 32.

Here, the second capacitance sensor 45 is shown in FIG.
As shown in FIG. 1, the central electrode 37 of the first capacitance sensor 32 is configured by using a central electrode 46 in which the radial dimension of the central electrode 37 is shortened (a1> a2). , And the other-side electrode 44 'is connected to another differentiating circuit 5.

Then, like the first capacitance sensor 32, the capacitance C2 of the alcohol mixed gasoline flowing between the center electrode 46 and the pipe member 33 'in the direction of the arrow is detected by the following mathematical formula 2. To do.

[0054]

[Equation 2] a2: radius of the central electrode b1: radius of the pipe member d: displacement of the central electrode with respect to the central axis of the inflow pipe K2: electrode constant of the second capacitance sensor εr: relative permittivity of alcohol mixed fuel ε0: vacuum dielectric Rate C0: Inherent capacity of detector

Reference numeral 47 indicates a reference signal line, and the reference signal line 47 outputs the reference voltage V01 of the oscillator 31 to the arithmetic unit 11.

In this embodiment having such a configuration, the reference voltage V01 having the frequency f is input to the capacitance sensors 32 and 45. The capacitance sensors 32 and 45
Then, since the distance between the center electrodes 37 and 46 which are one of the electrodes and the pipe members 33 and 33 'which are the other electrodes are different,
The electric field strength generated between these members can be made different. As a result, the strength of the dielectric polarization of the alcohol-blended gasoline flowing in the direction of the arrow is changed, and the capacitance C
1, C2 can be changed. Then, as described in the first embodiment, the characteristic maps similar to those in FIGS. 2 and 3 are created for the changes in the electrostatic capacitances C1 and C2, and the characteristic maps are stored in the arithmetic unit 7 as shown in FIGS. The unknown ethanol concentration EX and the unknown methanol concentration MX can be detected by the program shown in FIG. 7 and the individual concentration calculating means shown in FIG. Further, in this embodiment, it is possible to perform highly accurate detection with one oscillator without using two oscillators as in the first embodiment.

In the third embodiment, the case where the capacitance sensors 32 and 45 are coaxial cylindrical ones has been described, but the present invention is not limited to this, and the parallel plate electrostatic capacitances are used. A capacitance sensor may be used to form different electrode plate distances and cross-sectional areas so as to have different electrode constants.

In each of the above embodiments, each capacitance C1
, C2, the mixed lines L1 and L2 are calculated. However, the present invention is not limited to this, and the mixed lines L1 and L2 are calculated by calculating the relative dielectric constant in alcohol-blended gasoline. The unknown ethanol concentration EX and methanol concentration MX may be obtained from the mixing lines L1 and L2.

Furthermore, in each of the above-described embodiments, the intersection of the mixing lines L1 and L2 is calculated from the graph as shown in FIG. 7, but the present invention is not limited to this, and is calculated from each characteristic map. From the ethanol mixed concentrations E10, E11, ... and the ethanol mixed concentrations E20, E21, ... for the methanol mixed concentrations M0, M1, ..., Approximate expressions obtained by various approximation methods, and the intersections are found by solving the equations. Alternatively, the ethanol concentration and the methanol concentration may be calculated.

[0060]

As described above in detail, in the present invention,
Even when one alcohol and another alcohol are mixed in the alcohol-mixed fuel, the one alcohol concentration and the other alcohol concentration can be reliably detected. Also,
Even when one alcohol or another alcohol is mixed into gasoline alone, each one alcohol concentration or each other alcohol concentration can be individually detected by this alcohol mixed fuel property determination device.

Therefore, by providing the capacitance sensor in the middle of the fuel supply pipe of the engine of an automobile or the like, even if the alcohol mixed fuel of one alcohol and the other alcohol has any mixed concentration, the concentration can be detected with high accuracy. The fuel injection amount and the ignition timing can be accurately controlled. Then, the driving performance of the vehicle can be effectively improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an alcohol blending gasoline property determining apparatus according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a characteristic map I based on the measurement results of a known alcohol-blended gasoline with an attenuator of −39 dbm.

FIG. 3 is a characteristic diagram showing a characteristic map II based on measurement results of a known alcohol-blended gasoline with an attenuator of −65 dbm.

FIG. 4 is a flow chart showing a method for measuring a mixed concentration of unknown alcohol-blended gasoline.

FIG. 5 is a flowchart following FIG. 4;

FIG. 6 is a flowchart following FIG. 5;

FIG. 7 is a mixed line L1 calculated from characteristic maps I and II,
It is explanatory drawing which shows the calculation method of L2 and a mixed concentration.

FIG. 8 is an overall configuration diagram of a property discriminating apparatus for alcohol-blended gasoline according to a second embodiment of the present invention.

FIG. 9 is an overall configuration diagram of a property discriminating apparatus for alcohol-blended gasoline according to a third embodiment of the present invention.

FIG. 10 is an enlarged vertical sectional view showing a first capacitance sensor.

FIG. 11 is an enlarged vertical cross-sectional view showing a second capacitance sensor.

[Explanation of symbols]

 1 Capacitance Sensor 2, 3, 21, 22, 31 Oscillator 7 Arithmetic Device 8 Input / Output Control Circuit 9 Processing Circuit 10 Storage Circuit 10A Storage Area 23, 24 Attenuator 25 Adder 26, 27 Bandpass Filter 32 First Capacitance sensor 45 Second capacitance sensor I, II Characteristic map L1, L2 Mixed line EX Ethanol concentration MX Methanol concentration

Claims (2)

[Claims] 1. A capacitance sensor provided in one alcohol, another alcohol, or an alcohol mixed fuel in which both one alcohol and another alcohol are mixed, and a first voltage applied to the capacitance sensor. A first capacitance calculating means for calculating a capacitance or a relative permittivity according to a detection signal from the capacitance sensor, and a static capacitance when a second voltage is applied to the capacitance sensor. When the second capacitance calculating means for calculating the electrostatic capacitance or the relative permittivity by the detection signal from the capacitance sensor and the known mixing ratio of one alcohol and another alcohol are made variable, When the first storage means that stores the rate of change in capacitance or relative permittivity calculated by the capacitance calculation means and the known mixing ratio of one alcohol and another alcohol are made variable, The second The second storage means for storing the change rate of the capacitance or the relative permittivity calculated by the capacitance calculation means and the capacitance or the ratio for the unknown alcohol mixed fuel are calculated using the first capacitance calculation means. A first mixing line calculating means for calculating a dielectric constant and calculating a mixing line of one alcohol and another alcohol from the first storing means, and a second capacity calculating means for an unknown alcohol mixed fuel are used. Second mixed line calculation means for calculating capacitance or relative permittivity and a mixed line of one alcohol and another alcohol from the second storage means, and the first and second mixed line calculation The crossing point of the mixing line by the means is obtained, and from this crossing point, the one alcohol concentration in the alcohol mixed fuel, the other alcohol concentration, or the individual concentration calculating means for calculating the individual concentration of the one alcohol and the other alcohol is constructed. Property determination device of an alcohol mixed fuel and composed. 2. A first and a second capacitance sensor provided in an alcohol mixed fuel in which one alcohol, another alcohol, or both one alcohol and another alcohol are mixed, and having different electrode constants, First capacitance calculation means for calculating capacitance or relative permittivity by a detection signal from the capacitance sensor when a voltage is applied to the first capacitance sensor; and the second capacitance. A second capacitance calculation means for calculating capacitance or relative permittivity by a detection signal from the capacitance sensor when a voltage is applied to the sensor, and a known mixing ratio of one alcohol and another alcohol. When variable, the first storage means for storing the rate of change of the capacitance or the relative dielectric constant calculated by the first capacitance calculation means, and one known alcohol and another alcohol The mixing ratio of When variable, the second storage means for storing the rate of change in the electrostatic capacity or relative dielectric constant calculated by the second electrostatic capacity calculation means, and the first capacity for unknown alcohol-mixed fuel First mixing line calculating means for calculating capacitance or relative permittivity using a calculating means and calculating a mixing line of one alcohol and another alcohol from the first storing means, and an unknown alcohol mixed fuel A second mixed line calculation means for calculating a mixed line of one alcohol and another alcohol from the second storage means by calculating a capacitance or a relative permittivity using a second capacitance calculation means. The intersection point of the mixing lines by the first and second mixing line calculating means is obtained, and the one alcohol concentration, the other alcohol concentration or the individual concentration of the one alcohol and the other alcohol in the alcohol mixed fuel is calculated from this intersection point. That property determination device of an alcohol mixed fuel formed by composed of the individual concentration calculation means.