WO2015025245A2

WO2015025245A2 - Light signaling system for vehicles

Info

Publication number: WO2015025245A2
Application number: PCT/IB2014/063801
Authority: WO
Inventors: Mauro Testa; Giovanni ANDREINI; Roberto DONADONI
Original assignee: Bianchi, Mario
Priority date: 2013-08-21
Filing date: 2014-08-08
Publication date: 2015-02-26
Also published as: ITGE20130082A1; WO2015025245A3

Abstract

A light signaling device for a vehicle provided with illuminating means for daytime recognition located at the front of the vehicle, which illuminating means remain on during travel of the vehicle, which comprises means for detecting the braking effect of the vehicle (2) and means for regulating the light emission (31) of the illuminating means, which means for regulating the light emission vary the intensity of the light emission proportionally to the detected braking effect.

Description

Light signaling system for vehicles

The present invention relates to a light signaling system for a vehicle provided with illuminating means for daytime recognition located at the front of the vehicle, which illuminating means remain on during travel of the vehicle.

The term vehicle is intended to designate both a motor vehicle and a motorcycle or any kind of similar vehicle, which is adapted to run over urban and suburban streets or highways where further vehicles or pedestrians may be found.

Currently known systems have the purpose of providing a higher road safety both for pedestrians and for other drivers that run before the vehicle, by signaling when the vehicle is braking, as is usually done with the rear stoplight.

Providing information about the driver's intention to brake to road users, either other drivers of pedestrians, is of the utmost importance: for instance it would be advantageous, at a pedestrian crossing, or at crossroads, to allow a user to understand whether another user that is about to enter the crossroads has actually seen the vehicle and is braking with the intention to give way.

These systems further allow the driver of a vehicle that has stopped at a stop sign or a traffic light to realize whether the driver that comes next is braking or not, and to be prepared for a possible collision, thereby minimizing whiplash effects.

US 2007/0008096 Al discloses a system in which a warning light is mounted to the front of the vehicle and generates different flashing sequences and/or colors for vehicle braking and vehicle traveling, e.g. emits a red light when the vehicle is braking and a green light when the vehicle is traveling.

DE 20 2008 005 003 Ul also discloses a system with front lights, e.g. red or green lights, to signal that the vehicle is braking.

US 5,966,073 discloses a system that has blue lights at its front to indicate that the vehicle is braking, and particularly a white light is emitted with the vehicle is running, the light turns to blue when the vehicle brakes and turns back to white at the end of the braking effect.

The above documents disclose systems in which front lights are used to indicate braking with different colors for ready recognition.

Nevertheless, the introduction of these lights may cause confusion in the pedestrian or the driver of another vehicle, who may not recognize the actual meaning of these lights, and confuse them with aesthetic and non- functional lights, thereby not properly reacting to the information provided by such lights, i.e. that the vehicle is braking.

Also, the use of flashing sequences may be immediately mistaken with the light emitted by the direction indicators, regardless of the color of the emitted light. More significantly, current regulations, e.g. the European Standard 76/756/EEC, indicate that no flashing light is permitted, except the direction indicators and the warning signals, and that the front lights may only be selectively white or yellow.

The present invention has the object of obviating the above described prior art drawbacks, by providing a system as described hereinbefore, which, in addition, comprises vehicle braking effect detection means 2 and light emission regulating means 31 for regulating light emission from the illuminating means, which light emission regulating means vary the intensity of the light emission proportionally to the detected braking effect.

This allows to act on the equipment that is already provided on the vehicle, using as frontal stop light the lights which are already present on the vehicle, in particular the daytime travel front light, without adding any external devices. The aesthetic appearance of the vehicle remains therefore the same, without introducing any further elements that can alter or worsen it. It is therefore used only a control electronic unit comprising parts which already exist, i.e. already existing lights or lamps. The travel daytime front lights are lights that point forward and which are arranged for making the vehicle more easily visible during daytime travel.

In an embodiment, the vehicle braking effect detection means 2 comprise means for detection of the speed signal of the tachymeter of the vehicle.

The variation of speed detected by the tachymeter is thus used as a braking or deceleration indicator. This allows for minimizing the system components, and so for reduced costs and for production and maintenance easiness.

According to an improvement, the vehicle braking effect detection means 2 comprise means for the analysis of the speed signal of the tachymeter and for consequent recognition of an intentional braking.

That allows the system to distinguish an intentional braking of the driver from a mere deceleration, on the basis of the speed variation.

For example, a deceleration threshold value may be used, above which the analysis means decide that there is an intentional braking.

A memory unit may be used, as an improvement, which contains one or more predetermined speed patterns which are indicative of an intentional braking. When the detected speed variation follows the memorized pattern, for less than a predetermined error, the analysis means decide that there is an intentional braking.

In a further embodiment, the vehicle braking effect detection means 2 comprise at least an accelerometer.

In a further embodiment, the vehicle braking effect detection means 2 comprise at least an anemometer. The anemometer detect the reduction in speed of the vehicle on the basis of the air speed detected on the vehicle, and it is very reliable both with and without wind.

Preferably, the anemometer is constituted by a Venturi tube .

In combination whith the accelerometer, the anemometer allows to obtain a lot of information, as speed, acceleration and deceleration, lateral heelings of the vehicle, etc.

In an embodiment said lighting device emits white light and said light intensity regulating means vary the color temperature of the emitted light across a range from a start value to an end value, proportionally to the detected braking effect.

Thus, the braking effect is signaled at the front by varying the color temperature of the emitted light, while white light is maintained.

According to the European and US standards, white light falls within the following values in the color space of the CIE 1931 standard colorimetric system:

x = 0.31 (blue boundary)

x = 0.50 (yellow boundary)

y = 0.15 + 0.64x (green boundary)

y = 0.05 + 0.75x (purple boundary)

y = 0.44 (green boundary)

y = 0.38 (red boundary)

Color temperature is the temperature that a black body should have for the light radiation emitted from such body to appear chromatically as close as possible to the relevant radiation, and is measured in K.

As the color temperature of white light falls to lower values, light tends to amber, and as it rises to higher values, light tends to blue.

Advantageously, color temperature varies continuously, or seemingly so, across the range, and proportionally to the detected braking effect, such that the information provided to the pedestrian or the driver of another vehicle is as accurate as possible.

In one exemplary embodiment, the range is from 2800 K to 5500 K, preferably from 2854 K to 5000 K.

These values correspond to the standard CIE illuminant A (2854 K) and the standard CIE illuminant B (5000 K) , which are defined by the standard as admissible color temperature limits for white light.

Since the range is bounded by these values, said end value of the color temperature of the emitted light may be advantageously the low limit value, with a light tending to amber, or the high limit value, with a light tending to blue.

Thus, the strength of the braking effect is more easily recognizable by the pedestrian or the driver of another vehicle.

Said start value of the color temperature of the emitted light may be the limit value opposite to that of the end value, or any intermediate value, as deemed appropriate by the manufacturer or the user.

The lighting devices may be front high-beam headlamps, front low-beam headlamps, front position lights or preferably daytime running lights.

The light sources may be lamps of any currently known type.

In the preferred exemplary embodiment, in which the lighting device consists of daytime running lights, the light sources may advantageously be LEDs.

Color temperature may be varied in any known manner, preferably continuously, throughout the range .

If LEDs are used, multiple side-by- side LEDS with slightly different color temperatures may be provided, which may be sequentially turned on and off, such that the color temperature of the emitted light may change by discrete values but with an effect as close to a continuous variation as possible.

Also, instead of or in addition to the above, a series of RGB LEDs may be provided, in which the color temperature of the total emitted light is varied by changing the contribution of each color component .

In a preferred exemplary embodiment, the intensity of the emitted light is varied continuously from a start value, corresponding to a no-brake condition, to an end value, corresponding to the maximum braking effect, the end value being preferably higher than the start value.

In a further embodiment, said lighting device comprises a plurality of light emitting spots, and said light emission regulating means change the number of lit light emitting spots proportionally to the detected braking effect.

Here, the light emitting spots are LEDs, but they may be bulbs or any kind of known light source.

In a first variant, the LEDs may be lit or unlit one at a time, as the detected braking effect increases, and proportionally thereto, the LEDs being preferably arranged in a row, and creating the effect of a longer or shorter light bar.

In a second variant, the LEDs are lit or unlit by groups, to create a predetermined number of areas, the number of lit areas being proportional to the detected braking effect. According to a further exemplary embodiment, said light emission regulating means turn on all the light emitting spots when the braking effect detection means signal that the vehicle has started braking, and sequentially turn off the lit light emitting spots at a rate that is proportional to vehicle speed reduction.

Once the braking is detected, all the light emitting spots and they start to turn off as the speed decreases. This is particularly advantageous because the maximum intensity is obtained at the beginning of the braking, i.e. when it is important to signal for example to a pedestrian that the driver has recognized him/her and is going to stop. The number of light emitting spots on, and so the global light intensity, is proportional to the vehicle speed, and this allows to provide a very precise indication, like a "progress bar", of the deceleration trend.

This will provide indications about both the braking intensity and the deceleration of the vehicle, i.e. how fast the speed changes during braking .

In a further embodiment, said lighting device comprises at least one selective yellow light emitting point, and the light emission regulating means turn on said selective yellow light emitting spot as soon as the braking effect detected by said braking effect detecting means leads to the vehicle stopping totally, means being provided for detecting the speed of the vehicle.

Selective yellow is a color admitted by current regulations for front headlamps and may be thus used for signaling when the vehicle has totally stopped by braking .

In a further exemplary embodiment, said lighting device is adapted to be oriented by automatic orientation means.

The device may be oriented both vertically downwards or upwards and horizontally toward and away from the longitudinal center axis of the vehicle.

Automatic orientation means may comprise, for example, one or more electric motors controlled by feedback or open mechanisms, for defining the requested end position.

If the lighting device comprises a plurality of emitting spots, the orientation may be carried out on each emission point or group of emission spots or on the whole lighting device.

According to a variant embodiment, means are provided for detecting the presence of one or more persons in the space before the vehicle, such that said automatic orientation means may orient said lighting device toward the detected persons.

The presence detection means may be ultrasonic or radar systems or may use a camera for video acquisition and have person recognition means using segmentation software.

In a further variant embodiment, means are provided for detecting external light sources, such that said automatic orientation means may orient said lighting device according to the direction of the detected external light source, thereby maximizing visibility of the emitted light for an external user.

A visibility optimization rule may require emission to be as perpendicular as possible to the main direction of light emission from the external source.

A further optimization rule may consist in minimizing reflection of external light on any reflecting surfaces of the lighting device.

These and other features and advantages of the invention will be more apparent from the following description of a few embodiments shown in the accompanying drawings, in which:

Fig. 1 shows a diagram of the system of the present invention;

Fig. 2 shows color definition in the CIE 1931 x,y color space;

Fig. 3 shows a diagram of a further exemplary embodiment .

Figure 1 shows a diagram of the light signaling system of the present invention, said system comprising at least one lighting device 1 located at the front of the vehicle, vehicle braking effect detection means 2 and light emission regulating means for regulating light emission from the lighting device according to the detected braking effect.

The lighting devices 1 may be front high-beam headlamps, front low-beam headlamps, front position lights or preferably daytime running lights.

Front daytime running lights are automotive lighting devices located at the front of a motor vehicle, and are generally installed in pairs, to be automatically lit when the vehicle is running, and to emit light to increase vehicle visibility in daytime conditions .

The light sources may be lamps of any currently known type. In the preferred exemplary embodiment, in which the lighting device consists of daytime running lights, the light sources may advantageously be LEDs.

The braking effect detection means are preferably sensors connected to the brake pedal, such as piezoelectric sensors for sensing the pressure on the brake pedal, located at the area upon which the foot of the driver presses the pedal or in other appropriate areas according to the construction of the braking system.

Instead of or in combination with the above, the braking effect detection means may consist of sensors for detecting hydraulic pressure in the circuit of the braking system, or sensors for detecting hydraulic pressure in the hydraulic circuit for controlling brake calipers, or transducers for turning the speed signal of the speedometer of the vehicle into control signals, or an accelerometer .

In the example of Figure 1, the light emission regulating means of the lighting device 1 comprise a CAN bus 30, an electronic controller 31 and a converter 34.

The braking effect signal detected by the sensor connected to the brake pedal 2 is sent to the electronic controller 31 via electric cables, preferably via the CAN Bus 30.

The CAN (Controller Area Network) Bus 30 is vehicle bus standard which is designed to allow communications among microcontrollers and electronic devices in a vehicle without a host computer, and uses a message-based protocol, specially designed for automotive applications. The electronic controller 31 receives the braking effect signal as an input and generates an output signal for the lighting device 1 according to the detected braking effect.

The electronic controller 31 may be a dedicated electronic controller or an existing controller of the vehicle, such as the controller that comprises the ESP 32 and ABS 33 units.

Then this signal is turned by the converter 34 into a power signal for the lighting device 1.

The lighting device 1 emits white light and the light emission regulating means, particularly the electronic controller 31 vary the color temperature of the emitted light across a range from a start value to an end value, proportionally to the detected braking effect.

Figure 2 shows white light definition in a diagram of the CIE 1931 x,y color space according to current regulations.

As clearly shown by the area 4, white light falls within the following ranges of color space:

x = 0.31 (blue boundary)

x = 0.50 (yellow boundary)

y = 0.15 + 0.64x (green boundary)

y = 0.05 + 0.75x (purple boundary)

y = 0.44 (green boundary)

y = 0.38 (red boundary)

The electronic controller 31 varies the color temperature of the light emitted by the lighting device 1 in such area, within a range from 2854 to 5000 K, as easily determined in Figure 2, which shows a few significant constant-color temperature lines. As the color temperature of white light falls to lower values, i.e. toward 2854 K, light tends to amber, and as it rises to higher values, i.e. toward 5000 K, light tends to blue.

The electronic controller 31 varies color temperature in a continuous manner, or seemingly so, and proportionally to the detected braking effect.

Such proportionality may be of any type, i.e. linear or non- linear.

In one exemplary embodiment, the electronic controller 31 receives vehicle's speed and time values and calculates a deceleration value, which is used to generate a braking quality value, that causes the generation of a power signal for the lighting device 1 in the converter 34, at a predetermined and variable color temperature.

Color temperature may be varied in any manner known to the skilled person, preferably continuously, throughout the range.

If the lighting device 1 comprises LEDs, there may be LEDs having the same or different color temperatures, or a series of RGB LEDs.

In combination with the above, the electronic controller 31 also automatically varies the intensity of emission from the lighting device proportionally to the detected braking effect, thereby generating an additional signal for the converter 34.

The intensity of the emitted light is also varied continuously from a start value, corresponding to a no-brake condition, to an end value, corresponding to the maximum braking effect, the end value being preferably higher than the start value. The configuration as shown in Figure 1 is compatible with various embodiments that can be implemented when the lighting device 1 comprises a plurality of light emitting spots, such as preferably LEDs or possibly bulbs or light sources of any currently known type.

In a first exemplary embodiment, the controller 31 is set to change the number of lit LEDs proportionally to the detected braking effect.

In a further exemplary embodiment, the controller 31 is set to turn on all the LEDs when the brake pedal sensor signals that the vehicle has started braking, and sequentially turns off all the lit LEDs at a rate proportional to the reduction of vehicle speed as detected by the speedometer.

In a further exemplary embodiment, the lighting device 1 comprises at least one selective yellow LED and the electronic controller 31 is set to turn on the selective yellow LED as soon as the braking effect leads to the vehicle stopping totally, as reflected by a zero speed detected by the speedometer.

The selective yellow corresponds to the area 5 in the CIE 1031 x,y color space as shown in Figure 2.

The electronic controller 31 may further use the ESP 32 and/or ABS 33 units to detect whether the vehicle is skidding, and to accordingly control the lighting device 1 to emit a predetermined emergency signal .

Figure 3 shows a diagram of the exemplary embodiment in which the lighting device 1 is adapted to be oriented by automatic orientation means. The device may be oriented by one or more orientation motors 8, e.g. electric motors, both vertically downwards or upwards and horizontally toward and away from the longitudinal center axis of the vehicle.

The automatic orientation means also comprise a CAN Bus 30, an electric controller 31 and a converter 34, the CAN Bus 30 and the electric controller 1 being typically the same as shown in Figure 1.

If the lighting device 1 comprises a plurality of LEDs, the orientation may be carried out on each LED or group of LEDs or on the whole lighting device 1.

The CAN Bus 30 receives as inputs, alternately or in combination, the signals detected by a person detection unit 6 and an external light detection unit 7.

According to the signals generated by the person detection unit 6, the electronic controller 31 controls the orientation motor 8 to orient the lighting device 1 toward the detected persons, as admitted by the orientation range of the lighting device 1.

Likewise, according to the signals generated by the external light detection unit 7, the electronic controller 31 controls the orientation motor 8 to orient the lighting device 1 toward the detected external light source, to maximize visibility of the emitted light for an external user. Visibility optimization rules may require, for instance, emission to be as perpendicular as possible to the main direction of light emission from the external source, or external light reflections on any reflecting surfaces of the lighting device 1 to be minimized.

The above described system may be mounted to the vehicle both during fabrication and as a kit, after manufacture .

Claims

1. A light signaling system for a vehicle provided with illuminating means for daytime recognition located at the front of the vehicle, which illuminating means remain on during travel of the vehicle

characterized in that

it comprises vehicle braking effect detection means (2) and light emission regulating means (31) for regulating light emission from the illuminating means, which light emission regulating means vary the intensity of the light emission proportionally to the detected braking effect.

2. A system as claimed in claim 1, wherein the vehicle braking effect detection means (2) comprise means for detection of the speed signal of the tachymeter of the vehicle.

3. A system as claimed in claim 2, wherein the vehicle braking effect detection means (2) comprise means for the analysis of the speed signal of the tachymeter and for consequent recognition of an intentional braking.

4. A system as claimed in claim 1, wherein the vehicle braking effect detection means (2) comprise at least an accelerometer .

5. A system as claimed in claim 1, wherein the vehicle braking effect detection means (2) comprise at least an anemometer.

6. A system as claimed in claim 1, wherein said lighting device (1) emits white light (4) and said light emission regulating means vary the color temperature of the emitted light across a range from a start value to an end value, proportionally to the detected braking effect.

7. A system as claimed in claim 5, wherein said range is from 2800 K to 5500 K, preferably from 2854 K to 5000 K.

8. A system as claimed in one or more of the preceding claims, wherein said lighting device (1) comprises a plurality of light emitting spots, and said light emission regulating means (31) change the number of lit light emitting spots proportionally to the detected braking effect.

9. A system as claimed in claim 7 e 2, wherein said light emission regulating means (31) turn on all the light emitting spots when the braking effect detection means (2) signal that the vehicle has started braking, and sequentially turn off the lit light emitting spots at a rate that is proportional to vehicle speed reduction.

10. A system as claimed in one or more of the preceding claims, wherein said lighting device (1) comprises at least one selective yellow light emitting spot, and the light emission regulating means (31) turn on said selective yellow light emitting spot as soon as the braking effect detected by said braking effect detection means (2) leads to the vehicle stopping totally, means being provided for detecting the speed of the vehicle.

11. A system as claimed in one or more of the preceding claims, wherein said lighting device (1) is adapted to be oriented by automatic orientation means .

12. A system as claimed in claim 11, wherein means (6) are provided for detecting the presence of one or more persons in the space before the vehicle such that said automatic orientation means may orient said lighting device (1) toward the detected persons.

13. A system as claimed in claim 11, wherein means (7) are provided for detecting external light sources, such that said automatic orientation means may orient said lighting device (1) according to the direction of the detected external light source, thereby maximizing visibility of the emitted light for an external user.