JPH09113307A - Traveling parameter detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a traveling parameter detecting device which can easily detect the traveling speed, etc., of a vehicle. SOLUTION: A DC voltage outputted from the power source of a vehicle is inputted to an A/D-converting section 11. An AC component of the power generated by an alternator is contained in the DC voltage as a ripple. A pulse counter 12 measures the ripple per unit time and a determining section 13 for determining number of revolutions of engine calculates the number of revolutions of the engine of the vehicle. A car speed converting section 14 converts the number of revolutions of the engine into the traveling speed of the vehicle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling parameter detecting device, and more particularly to a traveling parameter detecting device for obtaining speed information of a vehicle used in a navigation system or the like.

[0002]

2. Description of the Related Art In a navigation system mounted on a vehicle such as an automobile, the position of the vehicle is generally detected. The following two methods are known as methods for detecting the position of a vehicle.

Method 1: GPS (Global Positioning Sys)
tem) to detect the position of the vehicle with assistance from an external facility Method 2: Method to detect the position of the vehicle based on signals from the azimuth sensor and the distance sensor mounted on the vehicle (hereinafter referred to as "autonomous method" The above method of detecting the vehicle position with the assistance of an external facility is a method of detecting the absolute position of the vehicle, so it has the advantage that error accumulation does not occur, but the accuracy of position detection is rough. In addition, it has the drawback that it cannot be used when the radio waves from the satellite do not arrive.

On the other hand, the above-mentioned autonomous system has an advantage that it is possible to trace a subtle change in the position of the vehicle with high accuracy. There is.

That is, since the above two methods are in a mutually complementary relationship, a hybrid method in which both methods are used together is becoming popular in recent years.

In the above-mentioned autonomous system, a gyro or compass is used as the direction sensor.

Accelerometers are used to calculate distances in aircraft and the like. This is because it is difficult for an aircraft to travel at a higher acceleration than a car and it is difficult to obtain distance data directly.

On the other hand, in the automobile, the rotation of the wheels is directly detected, and the traveling parameter such as the vehicle speed is detected based on the rotation of the wheels. The vehicle speed is integrated and used as distance information. The method of obtaining the vehicle speed based on the rotation of the wheels is the most popular at present.

FIG. 19 is a block diagram showing the configuration of a conventional vehicle navigation device. Referring to the drawings, a navigation device for a vehicle includes a navigation device body 1 that processes and calculates various signals, a vehicle speed sensor 6 that detects the number of rotations of wheels, and a gyro 3 that identifies a traveling direction of the vehicle. , GPS receiver 2.

The navigation device body 1 is supplied with power from the vehicle battery. The position information calculated by the navigation device body 1 is output to a display device such as a liquid crystal display.

[0011]

However, the method of detecting the vehicle speed by the rotation of the wheels as described above has the following problems.

Assuming that the navigation system is mounted on the vehicle from the stage of designing the vehicle, it is easy to extract the vehicle speed signal based on the rotation of the wheels.

However, in a retrofitting device such as a commercially available navigation system, it is necessary to perform work for extracting a vehicle speed signal based on the rotation of wheels from the vehicle. Normally, the vehicle speed signal based on the rotation of the wheels is a signal used only inside the automobile, and therefore the type of the signal and the extraction location are different depending on the vehicle type.

For these reasons, the construction for extracting the vehicle speed signal requires an investigation of the type of the vehicle speed signal for each vehicle type and the extraction location, and work based on specialized knowledge.
This has been a major factor preventing the spread of navigation systems that employ autonomous systems or hybrid systems that include autonomous systems.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a traveling parameter detecting device capable of easily obtaining traveling parameters such as vehicle speed.

Another object of the present invention is to provide a traveling parameter detecting device which can obtain accurate traveling parameters.

[0017]

In order to achieve the above object, a traveling parameter detecting device according to a first aspect of the present invention is based on a measuring means for measuring the engine speed and an engine speed measured based on the measured engine speed. And a calculating means for calculating a traveling parameter of the vehicle.

That is, in the traveling parameter detecting device according to the first aspect of the present invention, the rotational speed of the engine of the vehicle is measured, and the traveling parameter of the vehicle is calculated based on the measured rotational speed of the engine.

Therefore, it is not necessary to measure the number of rotations of the wheel as in the conventional case, and it becomes possible to easily acquire the traveling parameter.

A traveling parameter detecting device according to a second aspect of the present invention is the traveling parameter detecting device according to the first aspect, wherein the engine speed is measured based on a voltage fluctuation of a power supply system connected to the engine of the vehicle. To do.

In the traveling parameter detecting device according to the second aspect of the present invention, since the engine speed is measured based on the voltage fluctuation of the power supply system connected to the engine, the engine speed can be more easily measured. Is possible.

A traveling parameter detecting device according to a third aspect is the traveling parameter detecting device according to any one of the first and second aspects, further comprising an identifying means for identifying a gear ratio of the transmission, and a calculating means. Calculates traveling parameters of the vehicle based on the measured engine speed and the identified gear ratio.

This allows more accurate calculation of the running parameters. The traveling parameter detecting device according to a fourth aspect is the traveling parameter detecting device according to the third aspect, wherein the identifying means identifies the gear ratio based on the measured change in the engine speed.

As a result, the gear ratio can be identified more easily. The traveling parameter detecting device according to claim 5 is the traveling parameter detecting device according to any one of claims 1 to 4, wherein the traveling parameter detecting device identifies the current position of the vehicle and the traveling parameter detecting device at different times. The vehicle further includes a correction unit that corrects the calculated traveling parameter of the vehicle based on the displacement of the vehicle position.

Since the calculated movement parameter of the vehicle is corrected based on the displacement of the position of the vehicle between the different times thus identified, it becomes possible to detect the traveling parameter more accurately.

A traveling parameter detecting device according to a sixth aspect is the traveling parameter detecting device according to the fifth aspect, wherein the position identifying means includes a GPS receiving device.

A traveling parameter detecting device according to a seventh aspect is the traveling parameter detecting device according to any one of the first to sixth aspects, in which the traveling parameter includes a vehicle speed.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) The traveling parameter detection device according to the first embodiment of the present invention has the following two features.

(1) First Feature The first feature of the running parameter detection device according to the present embodiment is that the vehicle speed is measured based on the measured engine speed and the engine speed is measured. There is.
An automobile uses the rotation of an engine as a power source to travel by finally rotating wheels through a power transmission mechanism such as a clutch, a transmission, a propulsion shaft, a joint, and a final reduction gear.
That is, since the power source of the automobile is the engine, the vehicle speed is basically proportional to the engine speed. Therefore, the vehicle speed is detected based on the engine speed.

Although the vehicle speed is detected as the traveling parameter in the present embodiment, the traveling distance of the vehicle can be calculated as the traveling parameter in the same manner.

(2) Second Feature The second feature of the running parameter detection device of the present embodiment is that the engine speed is measured based on the voltage fluctuation of the power supply system of the automobile.

The engine speed can be obtained by extracting a signal from a tachometer or the like.

However, although the method of extracting the signal from the tachometer or the like can more easily retrieve the running parameters of the vehicle than the conventional method of obtaining the rotation of the wheels, the construction for extracting the signal from the tachometer or the like is still required.

On the other hand, in the present embodiment, the engine speed is measured based on the voltage fluctuation of the power supply system of the automobile. Thus, for example, the engine speed can be measured based on the fluctuation of the voltage output from the cigarette lighter plug.

That is, even a person who does not have a specialized knowledge of automobiles can easily install the device.

For example, in a car navigation system,
When the travel parameter detection device according to the present embodiment is applied, it is possible to detect travel parameters such as vehicle speed by measuring the voltage fluctuation of the power supply supplied to the navigation device.

Next, the configuration of the traveling parameter detecting device in the present embodiment will be described. FIG. 1 shows the first embodiment of the present invention.
FIG. 3 is a block diagram of a navigation system having the traveling parameter detection device in the embodiment of the present invention.

Referring to the figure, the navigation system is based on signals from a navigation device body 1 for processing and computing various signals, a gyro 3 for identifying the traveling direction of a vehicle equipped with the navigation system, and a satellite signal. GPS receiver 2 for identifying the current position of the vehicle by means of a vehicle, and a vehicle speed detecting device for detecting the vehicle speed (running parameter detecting device)
And 4.

FIG. 3 is a block diagram showing a specific structure of the vehicle speed detecting device 4 of FIG. Referring to the figure, the vehicle speed detection device 4 includes an A / D conversion unit 11 that performs analog / digital conversion of a power supply voltage supplied from a cigar plug or the like,
A pulse counter 12 that counts the pulses of the A / D converted signal, and an engine speed determination unit 13 that determines the engine speed based on the counted pulses.
And a vehicle speed conversion unit 14 that converts the determined engine speed into a vehicle speed.

Next, the operation of the traveling parameter detecting device according to the present embodiment will be described. 8 to 9 are diagrams showing the flow of current in the power supply system of an automobile according to the operating state of the automobile.

Referring to the figure, the power supply system of the automobile is roughly composed of a battery 10, a starter 9 of the engine, an alternator 7 for rectifying the AC voltage generated by the rotational force of the engine and outputting it as a DC voltage, and a head. It is composed of an electric load 8 composed of a light, a blinker, navigation and the like.

FIG. 8 is a diagram showing the flow of current when the engine is started. In this case, the current from the battery 10 is supplied to the starter 9 and the electric load 8. The current supplied to the starter 9 is higher than the current supplied to the electric load 8.

FIG. 9 is a diagram showing the flow of current during idling. In this case, the electric current output from the battery 10 and the alternator 7 is supplied to the electric load 8.

FIG. 10 is a diagram showing the flow of current when the vehicle is operating at high speed (during traveling). In this case, the current output from the alternator 7 is the electric load 8 and the battery 10
Entered as At this time, the battery 10 is charged.

In the state shown in FIGS. 8 and 9, the vehicle is stopped. On the other hand, in the state of FIG. 10, the vehicle is traveling. Therefore, the vehicle speed needs to be detected only in the state shown in FIG. In the state of FIG. 10, the traveling parameter detecting device detects the vehicle speed.

Referring to FIG. 10, the voltage applied to electric load 8 is a rectified DC voltage, and the voltage includes the voltage fluctuation of the original AC voltage as ripples.

FIGS. 5 and 6 are graphs showing the fluctuation of the DC voltage input to the electric load when the horizontal axis represents time and the vertical axis represents voltage.

Referring to the figure, the rectified DC voltage changes with the passage of time. That is, this voltage fluctuation forms ripples 41a to 41j.

This ripple is due to the AC component of the AC voltage before being rectified as described above. The AC voltage is output from an AC generator included in the alternator.

The AC generator is a device that converts the rotation of the engine into an AC voltage. Therefore, the ripple frequency is proportional to the engine speed.

From this principle, in the present embodiment, the engine speed is calculated based on the detected ripple frequency.

More specifically, referring to FIG. 7, (a)
The DC voltage V including the ripple that is input to the vehicle speed detection device 4 and the threshold voltage V ₀ shown in FIG.
Compared by 1.

As shown in FIG. 6B, when V> V ₀ ,
The A / D conversion unit 11 outputs an "H" level signal, and when V <V ₀ , the A / D conversion unit 11 outputs an "L" level signal.

The pulse counter 12 includes an A / D converter 11
The number of ripples per unit time is counted based on the signal output from.

Specifically, the pulse counter is, for example, A
The point at which the signal output from the / D converter 11 changes from the “H” level to the “L” level (marked with “X” in FIG. 7) is identified, and the identified point per unit time (for example, 1 second) Count the number. This count number corresponds to the ripple number per unit time.

The engine speed determining unit 13 converts the ripple number per unit time counted by the pulse counter 12 into an engine speed.

As shown in FIG. 2, the number of ripples per unit time and the number of engine revolutions per unit time are in a proportional relationship. Further, since one ripple is formed in one revolution of the engine, this constant of proportionality is usually 1. The engine speed determination unit 13 determines the engine speed based on this proportional relationship.

The vehicle speed conversion unit 14 is the engine speed determination unit 1
The engine speed converted by 3 is converted into the vehicle speed.

More specifically, in the vehicle speed converter 14, the engine speed is converted into a vehicle speed when the engine and the drive wheels are connected by the top gear (the gear with the smallest gear ratio).

Strictly speaking, even if the engine rotation speed is the same, the wheel rotation speed differs depending on the gear ratio of the transmission, and thus the vehicle speed also changes.

However, in normal traveling, the traveling time in the top gear is the longest. Also, since the travel distance per fixed time by the top gear is longer than the travel distance per fixed time by other gears, even if the speed is always obtained when traveling by the top gear, a fatal error occurs. There is no such thing.

FIG. 4 is a graph showing the relationship between the engine speed and the vehicle speed when the engine and the drive wheels are connected by the top gear.

As shown in FIG. 4, the vehicle speed conversion unit 14 calculates the vehicle speed by multiplying the engine speed by a constant for proportional conversion for obtaining the vehicle speed from the engine speed.

(Second Embodiment) FIG. 11 is a block diagram showing a specific configuration of a traveling parameter detecting device according to a second embodiment of the present invention.

Referring to the figure, the running parameter detecting device in the present embodiment is determined by engine speed judging unit 13 in addition to the configuration of the running parameter detecting device in the first embodiment shown in FIG. It is characterized by including a gear ratio determination unit 21 that determines the current gear ratio of the transmission on the basis of the determined engine speed, and a gear ratio storage unit 22 that stores the gear ratio.

The vehicle speed converter 23 shown in FIG. 11 converts the engine speed into speed based on the change in the gear ratio.

In the first embodiment, when the engine speed is converted into the vehicle speed, the conversion is always performed based on the gear ratio in the top gear.

Even if the vehicle speed is calculated only by the gear ratio of the top gear, a fatal error does not occur as described above,
If the gear ratio can be identified, the accuracy of vehicle speed detection is dramatically improved.

Although it is possible to obtain a signal indicating the gear ratio from the transmission of the automobile for the purpose of identifying the gear ratio, the adoption of such a method facilitates the installation of the device which is the object of the present invention. Will be difficult to achieve.

In the present embodiment, it is possible to easily identify the gear ratio and convert the engine speed to the vehicle speed based on the identified conversion ratio.

FIG. 12 is a graph showing the relationship between the engine speed and the elapsed time when the automobile is accelerated.

Referring to the figure, the gear ratio of the vehicle that started traveling at time a is changed at times b and c.

That is, when the gear ratio changes due to an upshift of the transmission or the like, the engine speed changes discontinuously. At the shift-up times b and c, the engine speed rapidly decreases.

FIG. 13 is a graph showing the relationship between the passage of time during deceleration of the automobile and the engine speed. Even when the gear ratio is downshifted when the vehicle decelerates, the engine speed changes discontinuously.

That is, at times f and g, the engine speed rapidly increases. The running parameter detection device in the present embodiment detects upshifts and downshifts by detecting these discontinuities in engine speed, and thereby identifies the gear ratio in which the vehicle is running. It has a feature.

More specifically, the processing performed by the gear ratio determining unit 21 shown in FIG. 11 will be described with reference to the flowchart of FIG.

Referring to the figure, when the vehicle starts to run, the memory is initialized in step S1. At this time, the gear ratio of the low gear (the gear with the largest gear ratio) is stored as the gear ratio stored in the gear ratio storage unit 22.

In step S3, the engine speed is input from the engine speed determination unit 13.

In step S5, it is determined whether or not the engine speed is changing rapidly. This abrupt change means the times b, c, f shown in FIGS. 12 and 13.
And g show discontinuous changes in engine speed.

If YES in step S5, it is determined in step S7 whether the engine speed is decreasing.

If YES in step S7, the gear ratio stored in the gear ratio storage unit 22 in step S9 is upshifted by one step.

On the other hand, if NO in step S7, the gear ratio storage unit 2 is operated in step S11.
The gear ratio stored in 2 is downshifted by one step.

After the processing in step S9 or S11,
The process from step S3 is repeated.

If NO in step S5, the processes from step S3 are repeated.

In the vehicle speed conversion unit 23, the engine speed is converted into the vehicle speed based on the gear ratio stored in the gear ratio storage unit. More specifically, a proportional constant corresponding to the conversion ratio stored in the gear ratio storage unit is selected from the plurality of proportional constants, and is multiplied by the engine speed.

As a result, in the present embodiment, the vehicle speed can be detected in consideration of the gear ratio, and the vehicle speed detection accuracy is improved as compared with the first embodiment.

When the vehicle is started from the second speed, or when the vehicle is decelerated, the gear ratio is not downshifted from the smaller gear ratio to the larger gear ratio, or the clutch is disengaged from the gear ratio of the top gear. By being
Although the vehicle may stop, the error caused by these is only a very small error in terms of the total traveling distance.

(Third Embodiment) A running parameter detecting apparatus according to the third embodiment is characterized by measuring a proportional constant between an engine speed and a vehicle speed based on a signal input from GPS. There is.

FIG. 15 is a block diagram showing the configuration of a navigation system using the traveling parameter detecting device according to the third embodiment of the present invention.

Referring to the figure, the navigation system according to the present embodiment is characterized in that a signal from GPS receiving device 2 is input to vehicle speed detecting section 4 as compared with the navigation system according to the first embodiment. I am trying.

FIG. 16 is a block diagram showing a specific structure of the vehicle speed detecting unit 4 shown in FIG. Referring to the figure, in addition to the configuration of the vehicle speed detection unit in the first embodiment, vehicle speed detection unit 4 in the present embodiment inputs the engine speed from engine speed determination unit 13, The present invention is characterized by including a proportional constant calculator 31 that calculates a proportional constant between the engine speed and the vehicle speed by inputting the current position of the vehicle.

The vehicle speed converter 32 outputs the vehicle speed by multiplying the engine speed determined by the engine speed determiner 13 by the proportional constant calculated by the proportional constant calculator 31.

FIG. 17 is a flow chart showing the processing performed by the proportional constant calculating unit 31 of FIG.

Referring to FIG. 17, in step S21, a timer for measuring time is reset.

In step S23, it is determined whether or not a signal indicating the current position has been input from the GPS. The process is suspended until YES in step S23.

If YES is determined in the step S23, the distance D traveled by the vehicle is determined in a step S25.
Is calculated, and the vehicle speed v is calculated by the equation (1) from the calculated distance D and the time t measured by the timer.

V = D / t (1) Here, with reference to FIG. 18, the distance D is defined by the coordinates of the vehicle currently identified by GPS being (X1, Y1), and measured by GPS before that. The coordinates of the vehicle (X0, Y0)
Then, the distance D is calculated by the equation (2).

D = ((X1-X0) ² + (Y1-Y0) ² ) ^1/2 (2) In step S27, the proportional constant a between the engine speed and the vehicle speed is calculated by the equation (3). .

A = v / r (3) Here, r is the engine speed per unit time determined by the engine speed determination unit 13.

The vehicle speed conversion unit 32 converts the engine speed into the vehicle speed based on the obtained proportionality constant a. The constant of proportionality a is updated each time a signal from GPS is input.

Accordingly, in this embodiment, the GP
Since the constant of proportionality between the engine speed and the vehicle speed can be calculated based on the signal input from S, it is possible to detect the traveling parameter with higher accuracy than the traveling parameter detecting device according to the first embodiment. Become.

Further, in the present embodiment, since the signal from the GPS which is independent of the vehicle type is used for calculating the proportional constant between the engine speed and the vehicle speed, the difference in the gear ratio depending on the vehicle type, the wear of the tire, It is also possible to compensate for changes in tire diameter due to changes in the people who are carrying it or in changes in luggage.

Although the vehicle speed is detected by the device in the above embodiment, it is also possible to calculate the traveling distance of the vehicle instead of the vehicle speed. In this case, the value output as the vehicle speed may be integrated.

Although the navigation device main body and the vehicle speed detecting device are described as separate devices in the above embodiment, the vehicle speed detecting device may be provided in the navigation device main body, for example.

[Brief description of the drawings]

FIG. 1 is a block diagram of a navigation system using a traveling parameter detection device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a ripple number per unit time and an engine speed.

FIG. 3 is a diagram showing a specific configuration of a vehicle speed detection device 4 in FIG.

FIG. 4 is a diagram showing a relationship between engine speed and vehicle speed.

FIG. 5 is a first diagram showing a change with time of a DC voltage input to the vehicle speed detection device.

FIG. 6 is a second diagram showing a change with time of a DC voltage input to the vehicle speed detection device.

FIG. 7 is a diagram for explaining a process performed by the A / D conversion unit 11 in FIG.

FIG. 8 is a diagram showing a current flow of a power supply system of the vehicle when the engine is started.

FIG. 9 is a diagram showing the flow of current in the power supply system of the vehicle during idling.

FIG. 10 is a diagram showing the flow of current in the power supply system of the vehicle during high-speed driving.

FIG. 11 is a block diagram showing a specific configuration of a traveling parameter detection device according to a second embodiment of the present invention.

FIG. 12 is a first diagram showing the operating principle of the traveling parameter detection device in the second embodiment of the present invention.

FIG. 13 is a second diagram illustrating the operating principle of the traveling parameter detection device according to the second embodiment of the present invention.

14 is a flowchart showing a process performed by the gear ratio determination unit 21 in FIG.

FIG. 15 is a block diagram of a navigation system including a vehicle speed detection unit according to a third embodiment of the present invention.

16 is a block diagram showing a specific configuration of a vehicle speed detection unit 4 in FIG.

FIG. 17 is a flowchart showing a process performed by a proportional constant calculating unit 31 of FIG.

FIG. 18 is a diagram for explaining the process performed in step S25 of FIG.

FIG. 19 is a block diagram showing a conventional navigation system.

[Explanation of symbols]

 1 Navigation Device Main Body 2 GPS 3 Gyro 4 Vehicle Speed Detector 11 A / D Converter 12 Pulse Counter 13 Engine Rotation Speed Judge 14 Vehicle Speed Converter 21 Gear Ratio Judge 22 Gear Ratio Storage 23 Gear Change Converter 31 Proportional Count Calculator 32 Vehicle speed converter 41 Ripple

Claims (7)

[Claims] 1. A traveling parameter detection device comprising: a measuring unit that measures an engine speed; and a calculating unit that calculates a traveling parameter of a vehicle based on the measured engine speed. 2. The traveling parameter detection device according to claim 1, wherein the measuring unit measures the engine speed based on a voltage fluctuation of a power supply system connected to the engine. 3. A discriminating unit for discriminating a gear ratio of a transmission is further provided, and the calculating unit calculates a traveling parameter of the vehicle based on the measured engine speed and the discriminated gear ratio. The travel parameter detection device according to claim 1 or 2. 4. The traveling parameter detecting device according to claim 3, wherein the identifying means identifies the gear ratio based on a change in the measured engine speed. 5. A position identifying means for identifying a current position of the vehicle, and a correcting means for correcting the calculated traveling parameter of the vehicle based on a displacement of the identified position of the vehicle between different times. The traveling parameter detection device according to any one of claims 1 to 4, which is provided. 6. The traveling parameter detecting device according to claim 5, wherein the position identifying means includes a GPS receiving device. 7. The travel parameter detection device according to claim 1, wherein the travel parameter includes a vehicle speed.