JPH0943207A - Fuel property judging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately judge a property of a fuel by a method wherein the effect of a noise except a primary reflection wave in a detected signal detected by an ultrasonic wave sensor is eliminated and a detection time from a transmission wave to the primary reflection wave is accurately measured, then a concentration of the fuel is calculated based on the detection time. SOLUTION: A signal processing circuit 21 is comprised of a transmission wave generation circuit 22, a time region selection circuit 23 and a detection time measuring circuit 24. The transmission wave generation circuit 22 consists of an ultrasonic wave oscillator 25, a divider circuit 26, a timing signal generation circuit 27 and a transmission wave output circuit 28. The time region selection circuit 23 consists of four switching circuits 30, 31, 32, 33 which are controlled by means of a dividing signal from the divider circuit 26. The time region selection circuit 23 selectively outputs a time region having a carrier wave and a primary reflection wave to the detection time measuring circuit 24 to accurately detect a detection time, thereby judging a property of the fuel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel property suitable for use in determining whether the fuel (gasoline) used in an automobile engine or the like is heavy oil or light oil. Regarding the discriminating device.

[0002]

2. Description of the Related Art In general, pure gasoline used as fuel for automobile engines includes light gasoline mainly containing hydrocarbons such as heptane and pentane and heavy gasoline mainly containing hydrocarbons such as benzene. There is gasoline, which can be further divided into three types: light gasoline, medium gasoline, and heavy gasoline.

[0003] Gasoline used in automobile engines usually has ignition timing set in accordance with light gasoline. However, recently, the use of heavy gasoline has become common, and due to the enforcement of the Air Pollution Law and the like, the use of heavy gasoline has been progressing to heavy oil.

However, matching with light gasoline,
When heavy gasoline is used as fuel in an engine that is set to control ignition timing, the ignition timing is delayed compared to light gasoline, resulting in a tendency to become lean as a whole and startability at low temperatures. However, there is a problem that driving performance is deteriorated. In addition, even in the running state, when heavy gasoline is used, not only does the running performance deteriorate, such as the breathing phenomenon, but also there arises a problem that harmful components in the exhaust gas increase due to incomplete combustion.

On the other hand, contrary to the above, when light gasoline is used in a gasoline vehicle that is set to match the heavy gasoline and control the ignition timing and the like, the overall tendency is to become overrich. There is a problem that "smoldering" occurs in the spark plug.

In order to solve the above problems, as a method for determining the fuel property, an optical property determining device utilizing the refractive index or reflectance of light is widely known.

This optical property determining device determines the fuel property based on the refractive index or reflectance of gasoline detected based on the unique refractive index or reflectance stored in advance.

[0008]

By the way, the above-mentioned optical property determining apparatus according to the prior art has a problem that the number of parts is increased because a light source, a receiving apparatus or a reflecting apparatus is required.

Further, if the surface of the light source, the receiving device, the reflecting device, or the like is contaminated, the amount of light, the refractive index, or the reflectance changes to cause an error, which makes it impossible to accurately determine the property. .

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention takes advantage of the fact that when ultrasonic waves are used, there is a time difference between the transmitter and the receiver depending on the properties of the fuel.
An object of the present invention is to provide a fuel property discriminating apparatus capable of discriminating a fuel property with high accuracy by measuring the time difference.

[0011]

In order to solve the above-mentioned problems, a fuel property discrimination device according to the invention of claim 1 is provided in the middle of a fuel supply pipe 100 and transmits a transmission wave of an ultrasonic signal. Ultrasonic measuring unit 1 for receiving reflected waves
10 and a signal for generating a transmission wave to be sent to the ultrasonic measurement unit 110 and measuring a detection time from transmission of the transmission wave to reception of a reflected wave by the detection signal detected by the ultrasonic measurement unit 110. The processing unit 120 and the signal processing unit 120
A signal processing unit 1 for determining the fuel property based on the detection time measured by the signal processing unit 1.
Reference numeral 20 denotes a transmission wave generating means 12 for generating an ultrasonic transmission wave for each predetermined timing signal toward the ultrasonic measurement unit.
1, a time domain selecting means 122 for selecting a time domain so as to output only the first reflected wave among the detection signals detected by the ultrasonic measuring unit 110, and the time domain selecting means 122. The detection time measuring means 123 for measuring the detection time using the first reflected wave in the detection signal, and the discrimination processing section 130 uses the characteristic of the density with respect to the detection time stored in advance to detect the detection time.
Density calculating means 132 for calculating the density based on the detection time measured by 3 and property judging means 1 for judging the fuel property from the density calculated by the density calculating means 132.
It is composed of 33 and.

According to the second aspect of the present invention, the transmission wave generating means 121 includes an ultrasonic oscillator for generating an ultrasonic signal, a frequency dividing circuit for dividing the ultrasonic signal output from the ultrasonic oscillator, A timing signal generating circuit that generates a timing signal based on a frequency-divided signal from the frequency dividing circuit, and an ultrasonic measurement of a transmitted wave by an ultrasonic signal from an ultrasonic oscillator based on the timing signal from the timing signal generating circuit. It is composed of a transmission wave output circuit for outputting to the unit 110.

According to the third aspect of the invention, the time domain selecting means 122 comprises a plurality of switching circuits which appropriately set the time domain by a frequency division signal obtained by dividing the ultrasonic wave of the transmission wave.

In the invention of claim 4, the property determining means 1
33 is that when the density calculated by the density calculating means 132 is high, it is judged as heavy oil, and when the density is low, it is judged as light oil.

[0015]

In the signal processing section 120 of the fuel property discrimination apparatus according to the first aspect of the present invention, the transmission wave generating means 121 generates the transmission wave of the ultrasonic wave toward the ultrasonic measuring section 110 at every predetermined timing signal, The time domain selecting means 122 selects the time domain so that only the first reflected wave of the detection signals detected by the ultrasonic measuring section 110 is output, and the detection time measuring means 123 selects the transmitted wave and the time domain selecting means 122.
The detection time is measured from the arrival of the first reflected wave in the detection signal output from.

Further, in the discrimination processing unit 130, based on the detection time calculated by the density calculation unit 132 using the signal from the timing signal transmission output from the detection time measurement unit 123 to the first reflected wave reception, The density can be calculated from the detection time-density characteristic 131 stored in advance, and the fuel property can be determined by the property determination means 133 from the calculated density.

According to the second aspect of the present invention, the transmission wave generating means 121 comprises the ultrasonic oscillator, the frequency dividing circuit, the timing signal generating circuit and the transmission wave output circuit. The frequency of the ultrasonic wave is divided, a timing signal is generated from the timing signal generation circuit based on this frequency-divided signal, and the transmission wave output circuit directs the transmission wave of the ultrasonic wave to the ultrasonic measurement unit at each predetermined timing signal. Can be output.

According to a third aspect of the present invention, the time domain selection means is composed of a plurality of switching circuits that appropriately set the time domain by a frequency division signal obtained by dividing the ultrasonic wave of the transmitted wave. The number of frequency divisions can be set by predicting the propagation distance of the formula measuring unit and the propagation velocity of the fuel, and only the time region in which the first reflected wave included in the detection signal exists is detected by the detection time measuring unit 123. Can be output to.

According to the invention of claim 4, the fuel property corresponds to the density, the heavy oil has a high density, and the light oil has a low density. Therefore, the property judging means calculates the density by the density calculating means. When the density is high, it is judged as heavy oil, and when the density is low, it is judged as light oil.
The fuel property can be accurately determined.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

First, the first embodiment of the present invention will be described with reference to FIGS.
The following shows an example.

In the figure, reference numeral 1 indicates, for example, a four-cylinder engine (only one cylinder is shown). The engine 1 is a cylinder 1A,
A cylinder head 1B mounted on the cylinder 1A,
A piston 1C reciprocates in the cylinder 1A. Reference numeral 2 denotes an ignition plug (only one is shown) provided on the cylinder head 1B located above each cylinder 1A. The ignition plug 2 is a cylinder when an ignition signal is output from a control unit 35 described later. It is designed to burn (explode) the air-fuel mixture in 1A.

The cylinder 3 of the cylinder 3 has a branch pipe on the base end side.
Shows an intake manifold provided on the intake side of the cylinder head 1B. An intake filter 4 is provided on the tip side of the intake manifold 3, and an air flow meter 5 for measuring an intake air amount and a throttle valve switch 6 are provided on the way. An attached throttle valve 7 is provided,
Further, an injection valve 8 is provided near the cylinder head 1B, and the injection valve 8 injects gasoline G into the engine 1 in response to an injection signal from the control unit 35.

A gasoline tank 9 stores gasoline G inside, and an in-tank type gasoline pump 10 is provided in the gasoline tank 9. Reference numeral 11 denotes a gasoline pipe as a fuel supply pipe, one end of the gasoline pipe 11 is connected to a discharge side of the gasoline pump 10 via a gasoline filter 12, and the other end is connected to an injection valve 8 and an inflow side of the pressure regulator 13. The outlet side of the pressure regulator 13 is connected to the gasoline tank 9 via a return pipe 14.

Reference numeral 15 denotes an ultrasonic measuring section of the fuel property discriminating apparatus according to the present embodiment, which is provided in the middle of the gasoline pipe 11, for example. As shown in FIG. 3, the ultrasonic measuring section 15 has a flange on the upper side. A bottomed tubular body 16 having a bottom and forming a portion 16A, a fuel inlet 17 located above the bottomed tubular body 16 and projecting in a radial direction, and the bottomed tubular body A fuel outlet 18 which is located below 16 and which is provided in a radially protruding manner;
A lid portion 19 that covers the flange portion 16A of the bottomed tubular body 16, and an ultrasonic sensor that is fixed to the lid portion 19 and that transmits an ultrasonic signal toward the bottom portion 16B of the bottomed tubular body 16. 20 and 20.

Here, since the inner peripheral surface of the fuel outlet 18 and the bottom portion 16B of the bottomed tubular body 16 are formed so that there is no step, the fuel flows from the fuel inlet 17 on the opening side to the bottom portion. The fuel flows continuously in the F direction indicated by the arrow toward the fuel outlet 18 on the 16B side. Since the ultrasonic measuring unit 15 is provided in the middle of the gasoline pipe 11, the fuel flows into the bottomed tube 16 from the fuel inlet 17 and the fuel in the bottomed tube 16 is removed. The fuel flows out smoothly from the fuel outlet 18 toward the gasoline pipe 11.

On the other hand, the ultrasonic sensor 20 is a transmission / reception integrated type having a transmitter and a receiver, and the transmitter and the receiver are composed of a piezoelectric vibrator, a magnetostrictive vibrator, an electromagnetic induction vibrator, or the like. There is. Then, by converting the electric energy into elastic energy in any of the vibrators, the ultrasonic signal is transmitted toward the bottom portion 16B, and the bottom portion 16B is transmitted.
The first reflected wave reflected at B (hereinafter referred to as the first reflected wave)
Is received by the ultrasonic sensor 20, elastic energy is converted into electric energy and is output as a detection signal.
In the ultrasonic measurement unit 15 according to the embodiment, the distance between the ultrasonic sensor 20 and the bottom portion 16B is the propagation distance L.
It has become.

Reference numeral 21 denotes a signal processing circuit as a signal processing section electrically connected between the ultrasonic measuring section 15 and the control unit 35. The signal processing circuit 21 is shown in FIG.
As shown in FIG. 3, it comprises a transmission wave generating circuit 22, a time domain selecting circuit 23 and a detection time measuring circuit 24 which will be described later.

Reference numeral 22 denotes a transmission wave generation circuit as transmission wave generation means, and the transmission wave generation circuit 22 is, for example, 512k.
An ultrasonic oscillator 25 that generates an ultrasonic signal of Hz, a frequency dividing circuit 26 that divides the ultrasonic signal output from the ultrasonic oscillator 25, and timing based on the frequency dividing signal from the frequency dividing circuit 26. A timing signal generating circuit 27 including a flip-flop circuit that generates a signal, and a transmission wave of an ultrasonic signal from the ultrasonic oscillator 25 based on the timing signal from the timing signal generating circuit 27 is output toward the ultrasonic sensor 20. And a transmission wave output circuit 28 for

Here, in the transmission wave generating circuit 22, the output of the ultrasonic oscillator 25 is connected to the frequency dividing circuit 26 and the transmission wave output circuit 28, and the output of the frequency dividing circuit 26 is connected to the timing signal generating circuit 27. The output of the timing signal generation circuit 27 is connected to the transmission wave output circuit 28.

Further, the 512 kHz ultrasonic signal output from the ultrasonic oscillator 25 is divided into 1/2 ⁸ by the frequency dividing circuit 26.
The timing signal of 2 kHz is output to the timing signal generation circuit 27, and the timing signal generation circuit 27
Generates a timing signal, which becomes a pulse having a predetermined width, toward the transmission wave output circuit 28. Then, in the transmission wave output circuit 28, the transmission wave for outputting the ultrasonic signal is output only while the timing signal is in the ON state.
Output to.

Then, in the ultrasonic sensor 20, a transmission wave is supplied to the transmitting portion, and by converting the electric energy into elastic energy, the ultrasonic signal is directed to the bottom portion 16B of the ultrasonic measuring portion 15. The first reflected wave transmitted and reflected by the bottom portion 16B is received by the receiving portion of the ultrasonic sensor 20, converts elastic energy into electric energy, and outputs it as a detection signal to the time domain selection circuit 23.

Reference numeral 23 denotes a time domain selection circuit as a time domain selection means, and the time domain selection circuit 23 is the amplifier circuit 2.
The first switching circuit 30, the second switching circuit 31, and the third switching circuit 3 which are connected to the subsequent stage of the transmission wave generation circuit 22 via 9 and are composed of switching elements.
2 and a fourth switching circuit 33,
The first switching circuit 30 is connected between the amplifier circuit 29 and the detection time measuring circuit 24, and the other switching circuits 31, 32, 33 are connected in series between the amplifier circuit 29 and the detection time measuring circuit 24. ing.

Reference numeral 24 denotes a detection time measuring circuit as a detection time measuring means connected to the subsequent stage of the time domain selecting circuit 23. The detection time measuring circuit 24 transmits based on the signal output from the time domain selecting circuit 23. The time from the wave generation to the reception of the first reflected wave is measured as a detection signal t, and this detection time t is output to the control unit 35.

Reference numeral 34 represents an inverter circuit connected between the frequency dividing circuit 26 and the second switching circuit 31. The inverter circuit 34 inverts the frequency dividing signal of 8 kHz output from the frequency dividing circuit 26. It outputs it.

On the other hand, the first switching circuit 30 transmits
When the transmission wave output from the wave output circuit 28 is input
When only the transmitted wave in the detection signal is detected because it is turned on
It outputs to the inter-measurement circuit 24. In addition, the second switch
The tuning circuit 31 outputs the ultrasonic signal output from the frequency dividing circuit 26.
Issue 1/2⁶  The divided signal of 8 kHz is input to
Only when it is turned on. Also, the third switch
The frequency circuit 32 outputs the ultrasonic signal output from the frequency dividing circuit 26.
1/2⁷ When the frequency divided signal of 4 kHz is input to
Only when it turns on. Furthermore, the fourth switching
The circuit 33 outputs the ultrasonic signal output from the frequency dividing circuit 1 to 1
/ 2⁸ When the divided signal of 2 kHz divided by is input
Only in the ON state.

Therefore, in the time domain selection circuit 23, the second
Switching circuit 31 to fourth switching circuit 33
By passing the detection signal output from the ultrasonic sensor 20 up to, the noise in the detection signal is removed and only the time region in which the first reflected wave exists is output.

Here, FIG. 5 shows waveforms at various points of the signal processing circuit 21 to explain the operation thereof. A to d are waveforms from the circuit constituting the transmission wave generating circuit 22, and a
The waveform of is the output from the ultrasonic oscillator 25, the waveform of b is the output from the frequency divider circuit 26, the waveform of c is the timing signal output from the timing signal generating circuit 27, and the waveform of d is the output from the transmission wave output circuit 28. Outputs to the sound wave sensor 20 are shown respectively.

Next, the waveforms e to l are time domain selection circuit 2
3 is a waveform from the circuit that constitutes 3, and the waveform of e is the transmission wave from the transmission wave generating circuit 22 and the detection signal from the ultrasonic sensor 20, and the waveform of f is 8 kHz output from the frequency dividing circuit 26.
A signal obtained by inverting the frequency-divided signal of z by the inverter circuit 34, the waveform of g is the output signal from the second switching circuit 31, and the waveform of h is 4 kHz output from the frequency-dividing circuit 26.
, The waveform of i is the output signal from the third switching circuit 32, the waveform of j is the divided signal of 2 kHz output from the frequency dividing circuit 26, and the waveform of k is from the third switching circuit 33. Output signal, waveform of l is time domain selection circuit 2
The output signals from 3 are shown respectively.

In the signal processing circuit 21 of this embodiment,
Even when the detection signal output from the ultrasonic sensor 20 is not only the transmitted wave and the first reflected wave but also the second reflected wave and other noises such as the waveform of e are detected, the time domain selection circuit 23, only the transmitted wave and the first reflected wave of the detection signal can be output to the detection time measuring circuit 24. Then, the detection time measuring circuit 24 detects the detection time t from the reception of the transmitted wave to the reception of the first reflected wave and outputs it to the control unit 35.

As a result, the time from the generation of the timing signal by the signal processing circuit 21 to the reception of the first reflected wave in the detection signal detected by the ultrasonic sensor 20 can be accurately detected as the detection time t. .

On the other hand, the frequency division number of the frequency division signal for driving the switching circuits 31, 32, 33 of the time domain selection circuit 23 is set as follows.

For example, the density is 700 to 800 kg / m ³
For two types of gasoline a and b within the range of, the propagation speed va of gasoline a is va = 970 m / s, gasoline b
When the propagation velocity vb of vb is 1115 m / s and the propagation distance in the ultrasonic measuring section 15 is L, the calculation time ta from the transmission wave generation of gasoline a to the reception of reflected wave and the gasoline b are calculated. The detection time tb from the generation of the transmitted wave to the reception of the reflected wave is given by the following mathematical expression 1.

[0044]

[Equation 1]

Then, the propagation velocities va and vb and the detection time t
The relationship between a and tb is as shown in the following Equation 2.

[0046]

## EQU00002 ## By va <vb, ta> tb

Here, f is an ultrasonic signal of 512 kHz
The period T of the divided signal when z is T = (1 / f) × B
(However, if the frequency division number is B: 2 ^X ), the condition of the frequency division signal for outputting only the first reflected wave in the detection signal is as shown in Equation 3.

[0048]

(Equation 3) ∴ ta f <B <2tb f

Therefore, the propagation speeds va and v
Substituting b gives Eq. 4.

[0050]

(Equation 4)

Substituting, for example, L = 0.1 m into this equation 2, the equation 5 is obtained.

[0052]

[Equation 5] 52.7 <B <92

At this time, B within the above range is 64 (= 2
^8), and the frequency dividing circuit 2 to operate the second switching circuit 31 based on the frequency-divided signal serving as the 1/2 ⁸
By setting 6, as shown in FIG. 5, it is possible to remove the time domain other than the first reflected wave in the detection signal and selectively output the time domain in which the first reflected wave exists.

Reference numeral 35 denotes a control unit which constitutes a discrimination processing portion of the fuel property discrimination apparatus according to this embodiment. The control unit 35 is composed of, for example, a microcomputer, and the control unit 35 is RA.
A storage circuit (not shown) including M, ROM, etc. is included, and in addition to the property determination processing program shown in FIG. 7, an injection amount calculation program, an ignition timing control program (neither is shown), etc. are incorporated. . Further, the map shown in FIG. 6 is stored in the storage area 35A.

Here, in the characteristic map shown in FIG. 6, for gasoline of which the known properties are determined, the horizontal axis indicates the detection time t at which the ultrasonic signal travels back and forth in the gasoline over the propagation distance L.
The vertical axis represents the density d [kg / m ³ ] and the detection time t is appropriately set according to the distance dimension of the propagation distance L.

The fuel property determining apparatus according to the present embodiment is constructed as described above. Next, the property determining process will be described with reference to the program shown in FIG.

First, in step 1, the time from the transmission of the transmission wave to the reception of the first reflected wave from the signal processing circuit 21 is detected as a detection time t, and in step 2, the detection time t is detected with reference to the map of FIG. The density d corresponding to the detected time t is calculated, and in step 3, the property is discriminated based on the calculated density d. That is, 2 of density d≤d0 and density d> d0
Judgment is made within one range (the unit of density d is kg / m
³ ).

If the density becomes d≤d0 in step 3, the process moves to step 4, the measured fuel is determined to be light gasoline, and in step 5, it is stored in the memory area 35A that the fuel is light gasoline. Then, the process returns in step 8.

In step 3, the density d> d0
When it becomes, it moves to step 6, it is determined that the measured fuel is heavy gasoline, the fact that the fuel is heavy gasoline is stored in the storage area 35A in step 7, and the process returns in step 8.

As described above, in the fuel property discriminating apparatus according to the present embodiment, the fuel density d is calculated from the detection time t from the ultrasonic sensor 20, and the fuel property is determined as light oil or heavy oil from the density d. Since it is determined whether or not the fuel property can be accurately determined. Then, engine control such as fuel injection amount and ignition timing control can be performed in an optimal state.

Also, the number of components of the ultrasonic measuring section 15 is small, and the ultrasonic measuring section 15 can have a simple structure.

Further, since the density d is detected by utilizing the ultrasonic wave, there is no problem due to deterioration with time as in the prior art, and therefore, there is no problem with high accuracy. It enables the determination of properties.

On the other hand, the bottomed tubular body 1 of the ultrasonic measuring section 15
Since No. 6 is formed so that there is no step between the bottom portion 16B and the fuel outlet 18, there is no stagnation in the bottomed tubular body 16, and the direction of the arrow F in FIG. It can flow smoothly and reduce the generation of vapor and the like. As a result, the ultrasonic signal from the ultrasonic sensor 20 can be prevented from being diffused by the boundary surface between the fuel and the stagnation portion, and the detection signal based on the ultrasonic signal can be accurately output.

Further, in the present embodiment, the signal processing circuit 21
The ultrasonic sensor 20 is controlled by the internal time domain selection circuit 23.
Since only the time region in which the transmitted wave and the first reflected wave exist in the detection signal output from is output to the detected time measuring circuit 24, the detected time measuring circuit 24 generates the first reflected wave from the transmitted wave. The detection time t until reception can be accurately detected.

As a result, the accurate detection time t can be output to the control unit 35, and the property of the fuel can be accurately determined by the property determination processing program shown in FIG. 7 in the control unit 35. Therefore, engine control such as fuel injection amount and ignition timing control can be performed in an optimum state.

In the first embodiment, steps 3 to 7 in the program shown in FIG. 7 are specific examples of the property determining means.

Next, FIG. 8 shows a second embodiment according to the present invention. The feature of this embodiment is that the property discriminating processing program built in the control unit 35 according to the first embodiment described above is Three types of properties, light oil, medium oil, and heavy oil, are discriminated. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. This embodiment will be described based on the property determination processing program shown in FIG.

First, in step 11, the time from the transmission of the transmitted wave to the reception of the first reflected wave is detected as the detection time t from the signal processing circuit 21, and in step 12, it is detected with reference to the map of FIG. The density d corresponding to the detection time t is calculated, and in step 13, the property determination is performed based on the calculated density d. That is, density d <d1, d1≤density d
<D2, the density d> it is determined in three ranges of d2 (The unit of density d is kg / m ^3).

If it is determined in step 13 that the density d <d1, the process proceeds to step 14 and it is determined that the measured fuel is light gasoline, and in step 15 it is determined that the fuel is light gasoline in the memory area 35A. , And returns in step 20.

In step 13, d1 ≤ density d ≤ d
When it is determined to be 2, the process proceeds to step 16, it is determined that the measured fuel is medium-quality gasoline, the memory area 35A stores that the fuel is medium-quality gasoline in step 17, and the process returns in step 20. To do.

Further, when it is determined in step 13 that the density d> d2, the process proceeds to step 18, and it is determined that the measured fuel is heavy gasoline, and in step 19, the fuel is heavy gasoline. Is stored in the storage area 35A, and the process returns at step 20.

As described above, in the fuel property discriminating apparatus according to the present embodiment, the fuel property is discriminated from the calculated density d as to whether it is light oil, medium oil or heavy oil.
The fuel property can be determined more minutely than in the first embodiment. Then, engine control such as fuel injection amount and ignition timing control can be performed in a more optimal state.

In the second embodiment, steps 13 to 19 in the program shown in FIG. 8 are specific examples of the property determining means.

Further, as shown in FIG. 9 of the third embodiment, the feature of this embodiment is that the ultrasonic measuring unit 41 is connected to the gasoline pipe 11
A straight tubular body 42 connected in the middle of the
2 and an ultrasonic sensor 43 provided on one side surface in the radial direction.

In this embodiment, the ultrasonic signal of the ultrasonic sensor 43 is reflected by the side surface on the other side and returns to the ultrasonic sensor 43, and propagates between the ultrasonic sensor 43 and the side surface on the other side. The distance is L2.

The ultrasonic measuring section 41 of the present embodiment having the above-mentioned structure is used as the ultrasonic measuring section 15 of the first embodiment.
In this case, the ultrasonic measuring section 41 can be formed with a simpler structure than the ultrasonic measuring section 15 according to the first embodiment. Furthermore, the straight tubular body 42 allows the gasoline to flow continuously.

Further, as shown in FIG. 10 in the fourth embodiment, the feature of the present embodiment is that the ultrasonic type measuring section 51 has an angled tubular body having curved portions 52A and 52B curved in an L shape. 5
2 and an ultrasonic sensor 53 that is provided on one curved portion 52A of the angled tubular body 52 and transmits an ultrasonic signal toward the other curved portion 52B.

Also in this embodiment, similarly to the third embodiment, the ultrasonic signal from the ultrasonic sensor 53 is reflected by the other bending portion 52B and returns to the ultrasonic sensor 53.
A propagation distance L3 (L3> L2) is provided between the ultrasonic sensor 53 and the other curved portion 52B.

The ultrasonic measuring section 51 of the present embodiment having the above-mentioned structure is used as the ultrasonic measuring section 15 of the first embodiment.
In this case, not only can the configuration be simpler than the ultrasonic measuring section 15 according to the first embodiment, but also the propagation distance L3 can be set longer.
And the detection sensitivity of the detection time t can be improved,
Subtle changes in density can be detected. Moreover, the flow of gasoline can be a continuous flow via the curved portions 52A and 52B.

[0080]

As described above in detail, according to the present invention of claim 1, in the signal processing section, the transmission wave of the ultrasonic wave is transmitted toward the ultrasonic measuring section by the transmission wave generating means at every predetermined timing signal. The time domain selecting means can select the time domain in which the first reflected wave exists in the detection signal detected from the ultrasonic measuring section and output it to the detection time measuring means. The means can accurately detect the detection time until the transmitted wave and the first reflected wave arrive.

Further, the discrimination processing unit stores in advance based on the detection time accurately calculated by using the signal from the timing signal transmission output from the detection time measurement unit to the first reflected wave reception by the density calculation unit. The density can be calculated from the detected detection time-density characteristics, and the fuel property can be determined by the property determining means from the calculated density, and the engine control such as the fuel injection amount and the ignition timing can be accurately performed.

According to the second aspect of the present invention, the transmission wave generating means comprises the ultrasonic oscillator, the frequency dividing circuit, the timing signal generating circuit and the transmission wave output circuit. The sound wave is divided, a timing signal is generated from the timing signal generation circuit based on this frequency-divided signal, and the transmission wave output circuit directs the transmission wave of the ultrasonic wave to the ultrasonic measurement unit for each predetermined timing signal. It is possible to output, and the measuring unit can detect the detection time by generating the transmitted wave and receiving the reflected wave.

As in the invention of claim 3, since the time domain selecting means is composed of a plurality of switching circuits for appropriately setting the time domain by a frequency-divided signal obtained by frequency-dividing the ultrasonic wave of the transmitted wave, ultrasonic measurement is performed in advance. The number of divisions can be set by predicting the propagation distance of the part and the propagation velocity of the fuel, and only the region where the first reflected wave included in the detection signal exists is selected and output to the detection time measuring means. In the detection time measuring means, noise other than the first reflected wave in the detection signal can be removed, and the detection time from the transmitted wave to the first reflected wave can be accurately measured. The properties can be accurately determined.

According to the invention of claim 4, the fuel property corresponds to the density, the heavy oil has a high density, and the light oil has a low density. Therefore, the property judging means calculates the density by the density calculating means. When the density is high, it is judged to be heavy oil, and when the density is low, it is judged to be light oil, so that the fuel properties can be accurately judged, and good engine control of fuel injection amount, ignition timing, etc. can be performed. it can.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a fuel property determination device according to the present invention.

FIG. 2 is an overall configuration diagram showing a fuel injection control device according to a first embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing an ultrasonic sensor used in the fuel property determination device according to the first embodiment.

FIG. 4 is a block diagram showing a fuel property determination device according to a first embodiment.

FIG. 5 is a diagram showing a waveform at each point in FIG. 4;

FIG. 6 is a characteristic diagram showing the density d with respect to the detection time t of known gasoline.

FIG. 7 is a flowchart showing a fuel property determination process according to the first embodiment.

FIG. 8 is a flowchart showing a fuel property determination process according to a second embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of an ultrasonic measuring section showing a third embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of an ultrasonic measuring section showing a fourth embodiment of the present invention.

[Explanation of symbols]

 11 Gasoline Pipe (Fuel Supply Pipe) 15, 41, 51 Ultrasonic Measuring Unit 20, 43, 53 Ultrasonic Sensor 21 Signal Processing Circuit (Signal Processing Unit) 22 Transmission Wave Generation Circuit (Transmission Wave Generation Means) 23 Time Domain Selection Circuit (time domain selection means) 24 Detection time measurement circuit (detection time measurement means) 25 Ultrasonic oscillator 26 Frequency divider circuit 27 Timing signal generation circuit 28 Transmitted wave output circuit 30, 31, 32, 33 Switching circuit 35 Control unit (determination) Processing unit) 100 Fuel supply pipe 110 Ultrasonic measuring unit 120 Signal processing unit 121 Transmitting wave generating unit 122 Time region selecting unit 123 Detection time measuring unit 130 Discrimination processing unit 131 Detection time-density characteristic 132 Density calculating unit 133 Property determining unit 133 t detection time

Claims (4)

[Claims] 1. An ultrasonic measuring unit, which is provided in the middle of a fuel supply pipe, emits a transmission wave of an ultrasonic signal and receives a reflected wave, and generates a transmission wave to be sent to the ultrasonic measurement unit. Together with the signal processing unit that measures the detection time from the transmission of the transmitted wave to the reception of the reflected wave by the detection signal detected by the ultrasonic measurement unit, and the fuel based on the detection time measured by the signal processing unit A determination processing unit for determining a property, the signal processing unit, a transmission wave generating means for generating a transmission wave of ultrasonic waves for each predetermined timing signal toward the ultrasonic measurement unit, and the ultrasonic wave The time domain selecting means for selecting the time domain so as to output only the first reflected wave of the detection signals detected from the expression measuring section, and the first reflected wave in the detection signal outputted from the time domain selecting means. Use to measure the detection time And a density calculation means for calculating the density based on the detection time measured by the detection time measurement means from the characteristic of the density with respect to the detection time stored in advance, A fuel property discriminating apparatus comprising a property discriminating unit for discriminating a fuel property from the density calculated by the density calculating unit. 2. The transmission wave generating means includes an ultrasonic oscillator that generates an ultrasonic signal, a frequency dividing circuit that divides the ultrasonic signal output from the ultrasonic oscillator, and a frequency dividing circuit that divides the ultrasonic signal. A timing signal generating circuit for generating a timing signal based on a frequency signal, and a transmission wave by an ultrasonic signal from an ultrasonic oscillator based on the timing signal from the timing signal generating circuit is output toward an ultrasonic measuring unit. The fuel property discriminating apparatus according to claim 1, wherein the fuel property discriminating apparatus comprises a transmission wave output circuit. 3. The fuel property according to claim 1, wherein the time domain selection means is composed of a plurality of switching circuits that appropriately set the time domain by a frequency-divided signal obtained by frequency-dividing the ultrasonic wave of the transmitted wave. Discriminator. 4. The fuel judging means judges as heavy oil when the density calculated by the density calculating means is high, and judges as light oil when the density is low. Fuel property determination device.