JPH08310296A - Vehicle deceleration display - Google Patents

Abstract

(57) [Summary] [Purpose] Even if deceleration is performed by other than a foot brake,
The deceleration is displayed in the same manner as the deceleration by the foot brake to prevent an accident such as a rear-end collision, and the deceleration can be accurately displayed even if the road surface is inclined. Further, the speed of deceleration detection can be increased, and the stepwise control of the indicator lamp lighting mode according to the change in deceleration can be easily realized. [Structure] One cycle time of a pulse signal having a cycle corresponding to the wheel speed output from the wheel speed corresponding pulse output circuit 1 is alternately measured by the pulse width measuring circuits 4 and 5, and the measurement result is converted. 6 and 7, each is converted into a frequency value f proportional to the wheel speed, and then subtracted by the subtraction circuit 8, and the subtraction result value Δf is compared with the display reference value fref from the display reference setting circuit 9. A comparison is made by the circuit 6, and when the frequency value f inputted first is larger than the frequency value f inputted later by the display reference value fref or more, the display signal is outputted and the indicator lamp 12 is turned on.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle deceleration display device for displaying a warning on a succeeding vehicle when the vehicle decelerates.

[0002]

2. Description of the Related Art In a conventional device of this type, as shown in FIG. 6, a switch 13 interlocking with the operation of a main braking device (foot brake) (not shown) is inserted between a power source E and braking lights 14, 14. , The brake lights 14,1 when the foot brake is activated
4 is turned on to display the following vehicle.

In such a conventional device, when the vehicle is decelerated by deceleration other than the operation of the foot brake, for example, engine braking, the brake lights 14 and 14 are not turned on.
Therefore, the following vehicle cannot immediately determine the deceleration of the preceding vehicle, and the deceleration of the preceding vehicle cannot be known until the distance between the following vehicle and the preceding vehicle decreases. Therefore, there is a risk of causing a delay in the brake operation of the following vehicle and causing an accident such as a rear-end collision.

Therefore, a device has appeared in which the deceleration display to the following vehicle is not dependent on the operation of the foot brake but the deceleration is directly detected and displayed. As shown in FIG. 7, this is provided with an acceleration sensor 15, an amplification circuit 16, a comparison circuit 17, a display reference setting circuit 18, a control circuit 19 and indicator lights 20 and 20. That is, the acceleration sensor 15 is used to detect deceleration, and when the acceleration (negative acceleration: deceleration) detected by the acceleration sensor exceeds the set value of the display reference setting circuit 18, the indicator lights 20 and 20 are turned on. Then, it is displayed on the following vehicle.

However, in such a conventional apparatus, due to the characteristics of the acceleration sensor 15 used, when there is a road surface inclination or a vehicle inclination, for example, when traveling on a slope, the gravitational acceleration (g sin θ).
Therefore, the 0G level fluctuates (shifts). Therefore, with the acceleration sensor 15 alone, an accurate deceleration of the vehicle could not be obtained under conditions other than road inclination = 0 ° or vehicle inclination = 0 °. In addition, accurate deceleration cannot be obtained even when vibration such as swaying occurs in the vehicle.

[0006]

As described above, in the prior art, it is not possible to display deceleration other than the operation of the foot brake, for example, engine deceleration, and there is a risk of causing an accident such as a rear-end collision. , Road slope,
There is a problem in that accurate deceleration of the vehicle cannot be obtained under conditions other than vehicle inclination = 0 ° or when vibration such as swaying occurs in the vehicle.

An object of the present invention is to display deceleration other than the operation of the foot brake in the same manner as the deceleration by the foot brake, prevent accidents such as rear-end collisions, and prevent the occurrence of an acceleration sensor. Even if there is road inclination, vehicle inclination, or vibration such as sway, the deceleration can be accurately detected and displayed. Another object of the present invention is to provide a vehicle deceleration display device capable of easily displaying the degree.

[0008]

The object is to input a wheel speed corresponding pulse output circuit which outputs a pulse signal having a cycle corresponding to the rotation speed of a vehicle wheel, and an output pulse of the wheel speed corresponding pulse output circuit. T flip-flop circuit,
A first pulse width measuring circuit for measuring the pulse width of either the H level or the L level of the output pulse of the T flip-flop circuit, and the first output pulse of the inverted output pulse of the T flip-flop circuit. A second pulse width measuring circuit for measuring a pulse width on the same level side as that measured by the pulse width measuring circuit; a first converting circuit for converting an output value of the first pulse width measuring circuit into a frequency value; A second conversion circuit that converts the output value of the pulse width measurement circuit into a frequency value, a subtraction circuit that subtracts the output value of the first conversion circuit from the output value of the second conversion circuit, and a deceleration display A display reference setting circuit in which the subtraction result value is set as a display reference value, a comparison circuit for comparing the display reference value from the display reference setting circuit with the subtraction result value from the subtraction circuit, and a comparison from this comparison circuit It is achieved by providing a control circuit for a point off control indicator in response to results.

[0009]

The wheel-speed-corresponding pulse output circuit outputs a pulse signal having a cycle corresponding to the rotation speed of the wheels of the vehicle without depending on the operation of the foot brake, and enables subsequent digital processing. The T flip-flop circuit inverts the output state (H or L level) every time the output pulse of the wheel speed corresponding pulse output circuit is input. Further, the output terminal and the inverted output terminal output pulses having mutually different polarities.

The first pulse width measuring circuit measures the pulse width on the level side of either the H level or the L level of the output pulse of the T flip-flop circuit, and the second pulse width measuring circuit.
The pulse width measuring circuit measures the pulse width of the inverted output pulse of the T flip-flop circuit on the same level side as the measurement by the first pulse width measuring circuit. As a result, the time of one cycle of the output pulse signal of the wheel speed corresponding pulse output circuit is measured alternately by the two pulse width measurement circuits.

The first and second conversion circuits convert the output values of the first and second pulse width measurement circuits into frequency values, respectively, and the relationship between the output value (frequency value) and the rotational speed (wheel speed) of the wheel. Is linear, that is, proportional. The subtraction circuit subtracts the output value of the first conversion circuit from the output value of the second conversion circuit, and the display reference setting circuit sets the subtraction result value when performing deceleration display as the display reference value. The comparison circuit is
The display reference value from the display reference setting circuit and the subtraction result value from the subtraction circuit are compared. The control circuit controls the turning on / off of the indicator lamp according to the comparison result from the comparison circuit. That is, when the deceleration becomes constant or exceeds the deceleration (the degree of deceleration becomes stronger than a certain value), the indicator light is turned on and the deceleration is displayed on the following vehicle.

As a result, even if the deceleration is not due to the operation of the foot brake, the deceleration is displayed in the same manner as the deceleration due to the foot brake, and an accident such as a rear-end collision can be prevented. Further, since it is not affected by gravitational acceleration unlike an acceleration sensor, deceleration is accurately detected and displayed even if there is road inclination, vehicle inclination, or vibration such as swaying in the vehicle. It will be.

Since the pulse width tw from the first and second pulse width measuring circuits is represented by 1 / f, it is displayed in a non-proportional relationship with the wheel speed (vehicle speed) v as shown in FIG. It is difficult to set the display reference value (display reference value of the display reference setting circuit) for lighting the lamp. Therefore, it is more difficult to set a plurality of types of display reference values, and even if deceleration display is possible, turning on or off the indicator lamp using a single display reference value is the limit. On the other hand, in the present invention, the relation between the output value (frequency value f) and the wheel speed v becomes proportional as shown in FIG. Not only can the value be set easily, the indicator light can be easily turned on or off using a single display reference value, and the display according to the deceleration change using multiple types of display reference values. It also becomes possible to easily realize stepwise control of the lighting mode of the lamp.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a vehicle deceleration display device according to the present invention. In FIG. 1, reference numeral 1 denotes a wheel speed-corresponding pulse output circuit for outputting a pulse signal having a cycle corresponding to the rotational speed of a wheel of a vehicle (not shown), and is composed of a wheel speed sensor 1a and a waveform shaping circuit 1b here.

In this case, the wheel speed sensor 1a is, for example,
Although not shown, an electromagnetic pickup having a built-in magnet and a gear that rotates integrally with the wheel are provided, and the sensor is configured to output an induced electromotive force (sine wave) having a cycle corresponding to the pitch of the gear according to the rotation of the wheel. In addition, the waveform shaping circuit 1b
Half-wave rectifies the sine wave output from the wheel speed sensor 1a,
The signal is converted into a square wave pulse signal (digital signal). Although the sine wave output from the wheel speed sensor 1a also changes in amplitude depending on the rotation speed of the wheel, the waveform shaping circuit 1b ignores the change in the amplitude and obtains a square wave pulse signal according to only the rotation speed of the wheel.

3 is a pulse output circuit 1 corresponding to the above wheel speed.
A T flip-flop circuit to which the output pulse of the (waveform shaping circuit 1b) is input, and includes an output terminal OUT1 and an inverting output terminal OUT2 that output signals having mutually different polarities.

Reference numeral 4 is an H (high) level or L of the output pulse of the output terminal OUT1 of the T flip-flop circuit 3.
The first pulse width measuring circuit measures the pulse width of one of the (low) levels, here, the H level side. Reference numeral 5 measures the pulse width of the output pulse (inverted output pulse) of the inverting output terminal OUT2 of the T flip-flop circuit 3 on the same level side as the measurement by the first pulse width measuring circuit 4, here, on the H level side. It is a second pulse width measuring circuit. As a pulse width measuring method by these pulse width measuring circuits 4 and 5, there is a method of counting the number of reference clocks of the device in the H level or L level of the input pulse of the circuits 4 and 5, here, in the H level period. Used.

6 is a first conversion circuit for converting the output value (pulse width measurement value) twA of the first pulse width measurement circuit 4 into a frequency value fA, and 7 is an output value of the second pulse width measurement circuit 5. It is a second conversion circuit that converts (pulse width measurement value) twB into a frequency value fB. Reference numeral 8 is a subtraction circuit to which the output value (frequency value fA) of the first conversion circuit 6 and the output value (frequency value fB) of the second conversion circuit 7 are input. , 7 output values (frequency values fA, f
In B), the subtraction process of (the frequency value fA or fB input earlier)-(the frequency value fB or fA input later) is performed, and the resulting value Δf (= fA-fB or fB-fA) is calculated. Output.

Reference numeral 9 is a single display indicating how the subtraction result value (frequency value) at the time of deceleration display is set as the display reference value fref, that is, how much the wheel speed (vehicle speed) decelerates before display. It is a display reference setting circuit in which a reference value fref is set. Reference numeral 10 is a comparison circuit for comparing the display reference value fref from the display reference setting circuit 9 and the subtraction result value Δf from the subtraction circuit 8 with the subtraction result value being the display reference value fref.
When it exceeds, it is judged that the display is necessary and the display signal is output.

Reference numeral 11 is a control circuit for turning on / off the indicator lamp, which turns on the indicator lamp 12 when a display signal is input from the comparison circuit 10 and turns off the indicator lamp 12 at other times.
As the indicator light 12, this may be used also as a brake light, or may be provided separately from the brake light.

Next, the operation of the device of the present invention will be described. First, the wheel speed sensor 1a outputs a sine wave signal (AC signal) having a cycle corresponding to the wheel speed. Although this output signal also changes in amplitude, the apparatus of the present invention does not require a change in amplitude, and since it is basically digitally processed thereafter, this signal is half-wave rectified by the waveform shaping circuit 1b. Also, it is converted into a square wave pulse signal (digital signal) by the built-in comparator. FIG. 2 is a waveform diagram showing this state. (A) is an output signal of the wheel speed sensor 1a, that is, an input signal of the waveform shaping circuit 1b, (b) is a half-wave rectified signal in the waveform shaping circuit 1b, (c). Is an output signal of the waveform shaping circuit 1b, that is, a square wave pulse signal (digital signal).

Here, the higher the wheel speed, the higher the frequency value of the output signal of the wheel speed sensor 1a. Therefore, the waveform shaping circuit 1b (wheel speed corresponding pulse output circuit 1)
The output signal cycle (time t in FIG. 2C) becomes shorter as the wheel speed becomes higher, and becomes longer as the wheel speed becomes lower. Therefore, in order to detect the deceleration state, it is sufficient to measure that the output signal period t of the wheel speed corresponding pulse output circuit 1 becomes longer than a certain length. In this case, the pulse width measuring circuit 4 determines the period t of two continuous square wave pulses of the output signal (square wave pulse signal) of the wheel speed corresponding pulse output circuit 1.
In FIG. 5, the T flip-flop circuit 3 is inserted so that it can be sequentially measured under the same conditions in terms of polarity.

The T flip-flop circuit 3 is a flip-flop whose output state (H or L level) is inverted each time a pulse is input, and the output terminal OUT1.
Signals having different polarities are output from the inverting output terminal OUT2. FIG. 3A is a waveform diagram of the output pulse signal of the wheel speed corresponding pulse output circuit 1 (waveform shaping circuit 1b) which is an input pulse signal of such a T flip-flop circuit 3, and FIG. 6 is a waveform diagram of an output pulse signal of the switching circuit 3. FIG. In FIG. 3A, t1 to t4
Each indicates one cycle of the output pulse signal of the pulse output circuit 1 corresponding to the wheel speed. Also, in FIG. 3B, twA1, twA2
Indicates the H level period of the output pulse signal of the output terminal OUT1 of the T flip-flop circuit 3, and twB1 and twB2 indicate the H level period of the output pulse signal of the output terminal OUT2 of the T flip-flop circuit 3.

From FIGS. 3A and 3B, the period t1 is the H level period twA1, the period t2 is the H level period twB1,
The cycle t3 corresponds to the H level period twA2, and the cycle t4 corresponds to the H level period twB2. That is, if the cycle t of the output pulse signal of the wheel speed corresponding pulse output circuit 1 changes, the H level period tw also changes at the same time. Therefore, the output pulse width of the output terminal OUT1 of the T flip-flop circuit 3 is changed by the first pulse width measuring circuit 4 and the inverted output terminal OU is changed.
By measuring the output pulse width of T2 by the second pulse width measuring circuit 5, it is possible to continuously detect the change in wheel speed (note that the relationship between the output pulse width and the wheel speed is shown in FIG. reference).

Next, the first conversion circuit 6 outputs the reciprocal (1 / t) of the output value (twA) of the first pulse width measurement circuit 4.
wA) is calculated and converted into a frequency value fA. Also, the second
The conversion circuit 7 outputs the output value (tw of the second pulse width measurement circuit 5
The reciprocal (1 / twB) of B) is calculated and converted into the frequency value fB. These first and second conversion circuits 6 and 7 make it possible to continuously output frequency values (see FIG. 5) that are proportional to the wheel speed. Subtraction circuit 8
With respect to the output value (frequency value fA) of the first conversion circuit 6 and the output value (frequency value fB) of the second conversion circuit 7, (the frequency value fA or fB input earlier) − (the input later) Frequency value fB or fA), and the resulting value Δf (= fA-fB or fB-fA) is output.

Here, since the frequency of the output signal of the wheel speed corresponding pulse output circuit 1 (waveform shaping circuit 1b) becomes higher as the wheel speed becomes higher, the first and second conversion circuits 6 for the running state of the vehicle. , 7 output values (frequency values) fA, f
B has the following relationship, assuming that fA temporally precedes fB. At constant speed: fA = fB At acceleration: fA <fB At deceleration: fA> fB Therefore, the subtraction result value Δf (here, f
A-fB) takes the following values: constant speed: 0, acceleration: negative, deceleration: positive.

The comparison circuit 10 has a display reference value fref from the display reference setting circuit 9 and a subtraction result value Δf from the subtraction circuit 8.
(Here, fA-fB), and when Δf> (or ≧) fref, that is, the subtraction result value Δf is the display reference value f
When ref is exceeded (the degree of deceleration has become stronger than a certain value) or when the vehicle has a certain deceleration, it is determined that the display is necessary and a display signal is output. The control circuit 11 receives the display signal and turns on the indicator lamp 12 to notify the following vehicle that the vehicle is in the decelerated state.

The operation described above is repeated while the vehicle is traveling,
During deceleration where Δf> (or ≧) fref, the control circuit 11
To the following vehicle to indicate that the vehicle is in a deceleration state.

In the above embodiment, the display reference setting circuit 9
And a single display reference value fref is set to
The single display reference value fref and the subtraction result value Δf from the subtraction circuit 8 are compared to determine the necessity of the deceleration display, and the control circuit 11 determines whether the deceleration display is necessary by the comparison circuit 10. I configured to turn on or off the indicator lamp 12 by
The present invention is not limited to such a configuration.
In the present invention, the relationship between the output value (frequency value f) and the wheel speed becomes proportional as shown in FIG. 5 by the first and second conversion circuits 6 and 7, and the display reference value fref in the display reference setting circuit 9 is set. Since it becomes easy to set, the display lamp lighting mode may be controlled stepwise by using a plurality of types of display reference values fref1, fref2 ... frefn. As an example, the display reference setting circuit 9 includes a plurality of types of display reference values fref1, fref2 ...
frefn is set, and the comparison circuit 10 compares the plurality of types of display reference values fref1, fref2 ... frefn with the subtraction result value Δf from the subtraction circuit 8 to determine whether deceleration display is required and each display reference value fref1, fref2. ... The magnitude of the subtraction result value Δf from the subtraction circuit 8 with respect to frefn is determined, and the control circuit 11 turns on or off the indicator lamp 12 in accordance with the result of the necessity of deceleration display by the comparison circuit 10, and Display reference value f
There is a configuration in which the lighting mode at the time of lighting the indicator lamp is controlled stepwise according to the judgment result of the magnitude relationship of the subtraction result value Δf from the subtraction circuit 8 with respect to ref1, fref2 ... frefn. Here, it is determined that the deceleration display is necessary, the display reference values fref1, fref2
This is done when the subtraction result value Δf reaches the display reference value corresponding to the minimum deceleration for deceleration display during frefn.
Further, as an example of stepwise control of the lighting mode, for example, the lighting intensity, the light emitting area, etc. are increased in deceleration (increase in the degree of deceleration).
It may be increased stepwise according to the above. In this case, when the lighting intensity and the light emitting area are increased and then accelerated, the lighting intensity and the light emitting area may be gradually decreased.

[0030]

As described above, according to the present invention, even when deceleration other than the operation of the foot brake, for example, the engine deceleration or the like, the indicator light (for example, a brake light) is turned on when the deceleration exceeds a preset value. Since this is done, the occurrence of an accident such as a rear-end collision can be prevented in advance, and there is an effect that the safety is improved.

Further, since the deceleration is detected from the change in the wheel speed (= the change in the vehicle speed), it is not affected by the gravitational acceleration unlike the acceleration sensor, and even if there is a road inclination or a vehicle inclination. Alternatively, there is an effect that the deceleration can be accurately detected and displayed even if vibration such as swaying occurs in the vehicle.

Further, according to the present invention, traveling (deceleration) of the vehicle
Since the state is basically detected by measuring the time of one cycle of the output pulse signal from the wheel speed corresponding pulse output circuit by the pulse width measuring circuit, there is also an effect that the operation time of deceleration detection is short.

Furthermore, the display reference value can be easily set in the display reference setting circuit, and the indicator lamp can be easily turned on or off using a single display reference value. There is also an effect that it is possible to easily realize the stepwise control of the indicator lamp lighting mode according to the deceleration change using the display reference value.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a device of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the waveform shaping circuit in FIG.

FIG. 3 is a time chart for explaining the operation of the device of the present invention shown in FIG.

FIG. 4 is a graph showing output values (pulse width measurement values) of first and second pulse width measurement circuits with respect to wheel speed.

FIG. 5 is a graph showing output values (frequency values) of the first and second conversion circuits with respect to wheel speed.

FIG. 6 is a block diagram of a conventional device.

FIG. 7 is a block diagram of a conventional device different from FIG.

[Explanation of symbols]

1 ... Wheel output pulse output circuit, 1a ... Wheel speed sensor,
1b ... Waveform shaping circuit, 3 ... T flip-flop circuit, 4
... first pulse width measuring circuit, 5 ... second pulse width measuring circuit,
6 ... 1st conversion circuit, 7 ... 2nd conversion circuit, 8 ... Subtraction circuit,
9, 18 ... Display reference setting circuit, 10 ... Comparison circuit, 11 ...
Control circuit for turning on / off the indicator lamp, 12, 20, ... Indicator lamp,
13 ... Switch, E ... Power supply, 14 ... Brake light, 15 ... Acceleration sensor, 16 ... Amplification circuit, 17 ... Comparison circuit, 19 ... Control circuit.

Claims (3)

[Claims] 1. A wheel speed corresponding pulse output circuit for outputting a pulse signal having a cycle corresponding to the rotation speed of a wheel of a vehicle, and an output pulse of this wheel speed corresponding pulse output circuit are input.
A flip-flop circuit, a first pulse width measuring circuit for measuring the pulse width of either the H level or the L level of the output pulse of the T flip-flop circuit, and the inverted output of the T flip-flop circuit. A second pulse width measuring circuit for measuring the pulse width of the pulse on the same level side as the pulse width measured by the first pulse width measuring circuit;
A first conversion circuit for converting the output value of the pulse width measurement circuit into a frequency value; a second conversion circuit for converting the output value of the second pulse width measurement circuit into a frequency value; and an output value of the first conversion circuit A subtraction circuit for performing subtraction with the output value of the second conversion circuit,
A display reference setting circuit in which a subtraction result value when performing deceleration display is set as a display reference value, and a comparison circuit for comparing the display reference value from the display reference setting circuit and the subtraction result value from the subtraction circuit, A deceleration display device for a vehicle, comprising: a control circuit for controlling lighting of a display lamp according to a comparison result from the comparison circuit. 2. A single display reference value is set in the display reference setting circuit, and the comparison circuit compares the single display reference value with the subtraction result value from the subtraction circuit to determine whether or not deceleration display is required. 2. The vehicle deceleration display device according to claim 1, wherein the control circuit turns on or off the indicator lamp according to a result of the necessity of deceleration display by the comparison circuit. 3. The display reference setting circuit sets a plurality of types of display reference values, and the comparison circuit compares the plurality of types of display reference values with the subtraction result values from the subtraction circuit to determine whether or not deceleration display is required. And the magnitude relationship of the subtraction result value from the subtraction circuit with respect to each display reference value, the control circuit turns on or off the indicator lamp according to the result of the necessity of deceleration display by the comparison circuit, and each display reference value. 2. The deceleration display device for a vehicle according to claim 1, wherein the lighting mode at the time of lighting the indicator lamp is controlled in a stepwise manner according to the result of the determination of the magnitude relationship of the subtraction result value from the subtraction circuit with respect to the value.