JPH06300765A - Speedometer for automobile of type displaying value corresponding to dry road - Google Patents

Abstract

PURPOSE:To set the safe running speed and the appropriate distance to a car ahead before entering a curve or braking the car by displaying a value corresponding to a dried road in addition to the actual speed and inducing the gradual deceleration when the holding force of tires by the road surface is decreased in comparison with the case when the car runs on a dry paved road. CONSTITUTION:The sliding amount between a not driven wheel and a driven wheel is obtained, and the driving force is divided by the sliding amount in the rotating direction, whereby a friction coefficient in the rotating direction of the tire is obtained. The speed corresponding to a dry road, the braking distance or the appropriate distance between cars are obtained with using the friction coefficient in the rotating direction as a substitutional value. The obtained numerical values are displayed on a display panel in a manner to identify easily. In other words, scales of the speed and scales of the appropriate distance between cars are provided respectively at the inner side and outer side of an LED display 21 of an arc. Moreover, the actual speed is shown at a part 22 indicated by oblique lines of the display 21. The part 22 is illuminated by a white light. A part 23 of the display 21 indicated by oblique lines represents the speed exceeding the actual speed of the value corresponding to the dry road, which is illuminated by a yellow light. The part 23 is indicated by white meshes when the value is a forecast. Each analog speed is digitally displayed at 24, 25, and also the temperature outside the car 27 and the temperature at the road surface 26 are digitally indicated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has been developed to reduce the risk of increased tire retention on roads due to rain, snow, icing, etc. It is added to the display panel of the speedometer to make it easy to see and to display quantitatively so that the speed required for safe driving can be easily changed. At the same time, the braking distance or the required inter-vehicle distance is quantitatively displayed so that an appropriate inter-vehicle distance can be easily obtained.

[0002]

2. Description of the Related Art Anti-skid brakes, traction controls and the like are available as safety devices for dealing with the above-mentioned decrease in road holding force, but there is no effect of relieving the decrease in friction force itself. If it decreases, the stopping distance increases almost inversely proportionally even if anti-skid is used, so the inter-vehicle distance increases in advance according to the decrease in frictional force.
Or, if the vehicle speed is not gradually reduced, the risk of a rear-end collision becomes great. Further, the traction control also has no function of preventing the breakout due to the centrifugal force from occurring when the vehicle enters a curved road at the same speed as the dry road when the road holding force is reduced. The driver can qualitatively understand the decrease in holding power from the scenery outside the vehicle, but it is difficult to obtain quantitative information. Since the speedometer, which is the central instrument for safe driving, is a quantitative display, if it is necessary to gradually reduce the speed for safety reasons, quantitative information is also required for the amount of reduction.
Skilled drivers intentionally try to obtain information by micro-steering or accelerating, but it is uncertain because it is feeling information, and naturally there are individual differences, and incorrect recognition is likely to cause accidents. .

[0003]

When the frictional force is reduced as described above, the speed and the inter-vehicle distance required for safety can be secured in advance before entering a curve or braking.

[0004]

In order to achieve the above object, the speedometer of the present invention uses a braking system in addition to the actual vehicle speed when the limit value for holding the tire on the road surface is lower than that on a dry paved road. Whether the distance has increased to the same value as when driving on a dry road at the same speed as when driving at that speed, that is, the dry road equivalent value is also displayed, and the driver gradually reduces the vehicle speed to a value necessary for safe driving. Induce the operation to be performed.

More specifically, since the kinetic energy is proportional to the square of the speed and the braking work amount is proportional to the first power of the braking force, the braking distance is inversely proportional to the braking force and the second power of the speed. Proportional. Therefore, the legal maximum speed is 100 km / h,
When running on a dry road that can brake 0.8G at a speed of 100km / h and you can only brake 0.2G due to snowfall, the braking distance is 0.8 divided by 0.2. It becomes four times. The speed at which the braking distance becomes four times on the dry road is the square root of 4,
That is, since it is double, the indicated value of the speedometer corresponding to the dry road of the present invention shows 200 km / h.

At this time, the driver has a dry road equivalent value of 100 per hour.
Basically, the correct response is to decelerate to the point where km is indicated. At this time, the actual speed is 50 km / h. However, due to circumstances such as transportation efficiency, it cannot be dropped to that point, so the actual speed is 75 km / h
When driving down to 0, the meter equivalent to dry road is 1 hour / hour
It shows 50 km, and there is a speed of 15 at the same time on a dry road.
Since the required braking distance at 0 km is also shown, the actual speed is 7
Even if the distance is 5 km / h, the distance between the cars will be maintained at a value equivalent to 150 km / h on dry roads, and the margin for breakout due to centrifugal force on curved roads will be reduced. Knowing that this is not the case, drive carefully, not only on curved sections but also on straight roads so that you do not have to turn the steering wheel suddenly.

In order to drive safely, the driver needs to concentrate on the judgment of the external situation, and the readability of the instrument is important. The converted value is indicated by the speedometer.

Further, a cruise control device having the above-mentioned indicated value as a target value may be used in some cases.

Since the above-mentioned limit value at which the road surface can hold the tire cannot be directly measured during running, the friction coefficient in the tire rotation direction was obtained as a substitute value, and it was obtained in advance from an experiment for that vehicle type. The dry road equivalent speed, the braking distance, or the appropriate inter-vehicle distance is obtained by referring to a look-up table or the like. For the friction coefficient in the rotation direction, a value obtained by dividing the driving force by the slip amount in the rotation direction is used. There are cases where the driving force is measured directly with a strain gauge stretched on the driving shaft, and cases where it is obtained from experimental data based on the accelerator opening, engine speed, gear ratio, torque converter inlet / outlet speed, etc. The amount of slip in the rotation direction is such that a gate signal is issued once every one to several revolutions of the non-driving wheel, the number of rotation pulses of the driving wheel between these is counted, and the number of pulses when the driving force is near zero is N. The value obtained by subtracting N from the number of pulses of is used as the slip amount. The value of N may be calculated from the relationship between the driving force at two or more points and the number of pulses during power running to correct the existing value.

As the gate signal, a non-contact displacement gauge may be used instead of the non-driving wheel to cause the gate signal to be transmitted at every constant traveling distance. In some cases, the friction coefficient may be estimated directly from the response characteristics, and in other cases, it may be estimated from the variation pattern of the angular acceleration of the drive wheels. Especially for all-wheel drive vehicles, it is necessary to rely on these means or provide dedicated wheels for measurement.

When the temperature outside the vehicle or the road surface temperature measured by an infrared thermometer falls below approximately zero degrees, there is a possibility of partial freezing of the road surface, so there is an icing portion at that temperature. The dry road equivalent value will be displayed as the notice value.

Even if the current straight road is a dry road,
The curved road ahead is frozen due to the shade, and in order to deal with the case where the surface of the curved road is dirty with mud and the ice surface cannot be seen,
In some cases, the infrared thermometer monitors the temperature of the front road surface. In addition to this, when the road surface temperature or the friction coefficient suddenly changes, an alarm such as a chime is issued.

The required amount of gradual decrease in speed is not simply the braking distance, but also the weight distribution of the front and rear wheels depending on the load, and the change in maneuverability and stability due to the change in the center of gravity of the truck. There is also a case where a speed that is considered is selected.

The device of the present invention is intended to maintain a required safety factor at all times, and the goal is not to cause an emergency. However, it is desirable to use an antiskid brake device in series. A traction control device is also required when trying to accelerate beyond the indicated value of the device of the present invention.

[0015]

[Operation] The speedometer configured as described above,
When the frictional force on the road surface decreases, the driver can quantitatively show the driver the speed and distance to safely drive and guide the driver to a safe value.

[0016]

EXAMPLES Examples will be described with reference to the drawings.
FIG. 1 shows the configuration of an embodiment of the device of the present invention. In the figure, 1 and 5 are gears that rotate in association with the rotation of non-driving wheels and driving wheels, respectively, and 2 and 6 are teeth when the gears rotate. The detector 3 for detecting the passage of the data of 3 receives the pulse of 2 and sends the speed data to the computer 4, and 7 receives the pulses of 2 and 6 to obtain the slip ratio, and sends the data to the computer 4. Reference numeral 8 is the above-mentioned road surface thermometer, which measures the road surface temperature in front of the course, and 9 is the above-mentioned outside air thermometer.

Since a rotational difference occurs geometrically between the inner and outer wheels and the front and rear wheels when traveling on a curved road, the steering angle is measured and corrected by the steering angle meter 10. In 11, the opening of the accelerator pedal is measured, and the drift of the driving force meter described later is corrected. Since the relationship between the pedal opening, the vehicle speed, and the driving force is roughly known in advance, it is possible to prevent the driving force meter from drifting to the extent that it causes practical problems. Is detected at the neutral position, and more accurate zero point correction of the driving force meter is performed. All of the above 8 to 12 data are sent to the computer 4. Reference numeral 13 is a non-volatile memory that stores the above-mentioned value of N, and 14 is a speedometer driven by the computer 4.

Reference numeral 15 is a drive shaft connected to the drive wheels, 16 is a strain gauge mounted on the drive shaft 15 and its protective cover for measuring the drive shaft torque, and 17 is its amplifier, which is connected to the coil 18 together with the coil 18. Combined and rotate with the shaft. Reference numeral 19 denotes a coil fixed to the vehicle body side, which transmits alternating current to the rotating coil 18 by electromagnetic induction, and the amplifier 17 rectifies the current and charges the capacitor, which is used as a power source via the switching regulator to measure the driving force. Transmits to the fixed coil 19 via the coil 18 in time division after averaging. The amplifier 20 excites the coil 19, periodically interrupts power transmission, receives the driving force digitally transmitted from the rotating coil 18 side in synchronization with this, and transfers the driving force to the computer 4. Driving force is coil 18, 19
In some cases, another wireless device may be used instead of the above.

FIG. 2 shows an embodiment of the display panel of the speedometer of the present invention. Reference numeral 21 denotes an LED display portion on an arc, which is for indicating the speed and the appropriate inter-vehicle distance, which is inside the arc. Is marked with a speed scale and the outside is marked with a car distance scale. A shaded portion 22 in 21 indicates a white lighting portion for indicating the actual speed.
It shows 5 km. 23 is the speed equivalent to the above dry route,
A yellow lighting portion showing a portion exceeding the actual speed is shown, and the illustrated example shows a speed of 150 km / h in the above-described example. In the case of the above-mentioned notice value, 23 is displayed in white mesh. Reference numerals 24 and 25 are digital display portions for the analog speeds, 27 is a vehicle outside air temperature, and 26 is a digital display portion for the road surface temperature on the forward course.

FIG. 3 shows the configuration of another embodiment of the device of the present invention. In the figure, 2a is an actual speed detector, and the actual vehicle speed is displayed on the speedometer 14 via the computer 4a. The driver visually observes the weather and the road surface condition and operates the changeover switch 7a to register it in the computer 4a.
In the illustrated example, dry channel, mud channel, rain, heavy rain or rut channel,
There are seven stages of fresh snow, pressure snow, and freezing, and from the value of the outside temperature thermometer 9 and the two-dimensional lookup table stored in the computer in advance, the limit value of the tire holding force on the road surface is estimated, In addition, the value of the driver's skill registration switch 28 is added to calculate the dry road equivalent speed, which is displayed on the speedometer 14. Contact 2 of switch 28
Reference numeral 9 indicates a case where the driver is a license holder, and reference numeral 30 indicates a case where the driver is two kinds. In some cases, various types and a large number of contacts may be provided in consideration of the individual's motor nerves and preferences.

FIG. 4 shows the construction of an embodiment of the cruise control device in which the indicated value of the speedometer of the present invention is used as the target value. The cruise control device 31 receives information from the computer 4b of the speedometer of the present invention. The engine output is automatically controlled so that the dry road equivalent speed shows a substantially constant value. Reference numeral 32 is a self-standing neutral type switch connected to the set lever of the cruise control, and when the lever is pushed upward, the contact 33 is opened to set the current dry road equivalent value. If it is a rainy area at this point, the actual vehicle speed will increase if it reaches a sunny area thereafter. When set on the side of the contact 34, this acceleration is not performed, but deceleration in the opposite case is performed. Yes is required for safety on the deceleration side, but those who feel uncomfortable with automation on the speed-up side should choose it. Reference numeral 35 is a speed setter that specifies the speed with a numeric keypad, etc., regardless of the current speed, and is a self-standing neutral switch 36 connected to the set lever.
When is pushed up, the contact 37 is opened, the set value is input to the computer as the actual running value, the dry road value at that time is set to cruise, and the set value is directly input as the dry road value when it is opened to 38. It 39 is a receiver for inputting the limit value of the dry road speed from a wireless transmitter on the ground, the output of which is contact 4
If the number is 0, the dry road value cannot exceed the limit regardless of whether the cruise is set or not. In the case of connecting to the No. 41 side, regardless of the manual instruction, when the wireless signal is received, the wireless instruction value is set as the cruise set value and the priority interrupt is performed.

FIG. 5 shows an embodiment of a road sign showing an upper limit value of the dry road equivalent speed. 42 is a sign board, 43 is a pillar to which a sign board is joined at the upper end, and the lower end is a prop fixed to the road side, and 44 is Numerical value entry section showing the limit value of dry road equivalent speed.
It shows 0 km / h. 45 is an example of a symbol mark to show that this displayed value has a different meaning from the conventional product, 46
Is an example in which the same thing is shown in text as an auxiliary sentence. At the same time, the value of 44 may be transmitted to the vehicle side by a wireless transmitter (not shown) as described above.

[0023]

Since the present invention is constructed as described above, it has the following effects.

By displaying the degree of danger on a slippery road quantitatively and displaying the gradual decrease in speed as a countermeasure against it, it is possible to easily and safely drive without requiring skill. Become.

Most road signs indicating the maximum speed have a fixed display value, so the display value tends to be set at an intermediate value between dry road and wet road. Has reduced the transportation efficiency of. In addition, it is dangerous because it is common sense to detect this and to drive at a speed higher than that by personal sensory judgment. On the other hand, when the friction coefficient greatly decreases, there is a tendency that the displayed value is adversely affected and the necessary deceleration is not performed. If the speedometer of the present invention is used, the displayed value can be adjusted to a dry road, so that the transportation efficiency can be safely increased, and necessary deceleration can be performed on a wet road, which enables sharp and safe driving. Become.

While traveling, the scenery outside the window moves in proportion to the speed, so that the approximate speed can be recognized without depending on the speedometer, but the braking distance, which is more important for safety than speed, is as described above. Since it is proportional to the square of the speed, it is difficult to recognize, and a meter display is required. Especially on highways, since there is a minimum speed limit, it is not possible to experience a stop from the maximum speed, so it is easy for a pool accident to occur and it is important to display the braking distance. Although the equivalent speed instruction value of the present invention is a virtual value as a speed, it can show an actual value as a braking distance or a required inter-vehicle distance.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a speedometer of the present invention.

FIG. 2 is a diagram showing an embodiment of the display panel of the speedometer of the present invention.

FIG. 3 is a diagram showing a configuration of another embodiment of the speedometer of the present invention.

FIG. 4 is a diagram showing a configuration of an embodiment of a cruise control device in which an indicated value of a speedometer according to the present invention is used as a target value.

FIG. 5 is a diagram showing an example of a road sign indicating an upper limit value of a dry road equivalent speed.

[Explanation of symbols]

 2 Non-driving wheel pulse detector 6 Driving wheel pulse detector 16 Strain gauge for driving force detection 22 Actual speed display section 23 Incremental display section from the actual speed of dry road equivalent speed 7a Road registration switch 28 For fineness registration Changeover switch 31 Cruise control device 42 Sign board

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[Procedure amendment]

[Submission date] June 17, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

[Title of the invention] Speedometer for displaying values equivalent to dry roads for automobiles

Claims (3)

[Claims] 1. A speedometer which shows a speed higher than an actual vehicle speed when a tire holding power of a road is lower than that of a dry paved road. 2. A cruise control device in which the indicated value of the speedometer according to claim 1 is used as a target value. 3. A road sign which is distinguished from a conventional speed regulation sign by a character, a difference in paint color, a mark or the like in order to regulate the upper limit value of the indicated value of the speedometer according to claim 1.