Vehicle with a driving assistance system for controlling the light intensity of rear lights when passing through a tunnel, and corresponding method

Abstract

A vehicle (A) equipped with a driving assistance system including one or more sensors (S) for detecting a first condition where the vehicle (A) is about to enter a tunnel (1) and a second condition where the vehicle (A) is about to exit the tunnel. The driving assistance system includes an electronic controller (E) configured to receive data from the sensors (S) and process said data, also based on data (S1) relating to the vehicle's speed, to obtain predictive information about the time needed to reach the entrance (1A) of a tunnel, when the vehicle is in said first condition, and the time needed to reach the exit (1B) of a tunnel (1), when the vehicle is in said second condition. The electronic controller (E) is programmed to bring the light intensity of the beam emitted by each rear light of the vehicle (A) to a maximum value (M1, M2), significantly higher than a predetermined nominal value (N), at the instant when the vehicle enters a tunnel and at the instant when the vehicle exits the tunnel, thus making the vehicle clearly visible to following vehicles, despite the critical visibility conditions due to the sudden change in ambient brightness at tunnel entrance and exit. The intensity of the beam emitted by the vehicle's rear lights is progressively reduced from the maximum value (M1) to the nominal value (N) over a given time interval after entering the tunnel and is again increased from the nominal value to the maximum value (M2) over a determined time interval before exiting the tunnel. The system drastically reduces the risk that the vehicle may not be seen by a following vehicle due to the sudden change in illumination at tunnel entrance and exit.

Description

[0001] VEHICLE WITH A DRIVING ASSISTANCE SYSTEM FOR CONTROLLING THE LIGHT INTENSITY OF REAR LIGHTS WHEN PASSING THROUGH A TUNNEL, AND CORRESPONDING METHOD

[0002] Field of the invention

[0003] The present invention relates generally to driving assistance systems for vehicles, namely the so-called "ADAS" ("Advanced Driver Assistance Systems"), and particularly concerns a system for automatically controlling the light intensity of a vehicle's rear lights when the vehicle enters a tunnel and when the vehicle exits a tunnel.

[0004] Background of the invention

[0005] The driver of a vehicle that is about to enter a tunnel during daytime may experience a significant reduction in his ability to clearly distinguish the scene ahead of the vehicle, due to the sudden change in lighting that occurs at the tunnel entrance. There is a critical time interval during which the driver of a vehicle about to enter a tunnel may not be able to promptly detect the presence of another preceding vehicle traveling at lower speed that has already entered the tunnel, which naturally entails a collision risk. The same situation may occur at tunnel exit. This situation arises because the human eye requires a certain time interval to adapt to the abrupt change in illumination levels, during which there exists a high risk of collision with a preceding vehicle traveling at lower speed.

[0006] During daytime, at tunnel entrance there is an abrupt change from a brighter to a darker environment, while at tunnel exit there is an abrupt change from a darker to a brighter environment. Both situations are critical, although the entrance situation is more critical since the human eye adapts more slowly when transitioning from light to dark compared to dark to light.

[0007] The present invention stems from the desire to equip a vehicle with a driving assistance system capable of reducing or entirely eliminating the risks associated with the aforementioned critical conditions.

[0008] Document JP 2009 248911 A illustrates a driving assistance system for a vehicle comprising sensors for detecting when the vehicle is about to enter or exit a tunnel, and an electronic controller that, based on sensor data, progressively decreases rear light intensity after tunnel entry and progressively increases it again near tunnel exit. Further solutions are known from documents WO 2004 / 106111 A1, JP 2011 179201 A, FR 3095 029 A1 and EP 3 822 123 A1

[0009] Object of the invention

[0010] It is therefore an object of the present invention to provide a vehicle equipped with a driving assistance system that significantly reduces or entirely eliminates the risk that the vehicle may not be seen by the driver of a following vehicle when entering or exiting a tunnel.

[0011] A further object of the invention is to achieve said objective with relatively simple and low-cost means.

[0012] Summary of the invention

[0013] To achieve said object, the invention relates to a vehicle comprising one or more rear lights, including position lights, stop lights and preferably also rear fog lights, wherein at least part of said rear lights include:

[0014] - a plurality of light sources, selectively activatable to vary the total light intensity of the light beam emitted by the rear lights, or

[0015] - one or more light sources, provided with an electronic control unit configured to make said light sources emit a light beam with intensity variable according to a signal sent by the electronic control unit, wherein said vehicle comprises a driving assistance system including:

[0016] - one or more sensors, for detecting a first condition where the vehicle is about to enter a tunnel and a second condition where the vehicle is about to exit a tunnel, and

[0017] - an electronic controller, configured to receive data from said one or more sensors and process said data, also based on vehicle speed data, to obtain predictive information about the time needed to reach tunnel entrance when the vehicle is in said first condition, or the time needed to reach tunnel exit when the vehicle is in said second condition, and wherein the electronic controller is programmed to:

[0018] - bring the light intensity of each rear light's beam to a maximum value, significantly higher than a predetermined nominal value, at the instant when the vehicle enters the tunnel and when the vehicle exits the tunnel,

[0019] - progressively decrease the light intensity of each rear light's beam from said maximum value to said predetermined nominal value over a determined time interval after tunnel entry,

[0020] - progressively increase the light intensity of each rear light's beam from said predetermined nominal value to a maximum value over a determined time interval, before the instant when tunnel exit is expected,

[0021] - return the light intensity of each rear light's beam to said predetermined nominal value after tunnel exit.

[0022] Thanks to these features, when the vehicle enters or exits a tunnel, the driving assistance system automatically increases the intensity of the light beam emitted by the vehicle's rear lights, making the vehicle immediately more visible to any following vehicle, thus drastically reducing the risk that the vehicle equipped with the system according to the invention may be hit by a faster following vehicle. In this condition, the higher intensity of the light beam emitted by the rear lights of the vehicle equipped with the system according to the invention makes the vehicle clearly visible to following vehicles, even in the critical conditions occurring at tunnel entrance and exit.

[0023] As indicated, the means for varying the light intensity of the rear lights' beam can be any. In particular, each rear light may include a plurality of selectively activatable light sources. Alternatively, the rear lights' light sources may be configured to emit a light beam with intensity variable according to the current signal sent by the light sources' electronic control unit. Or, the rear lights may have light sources provided with a plurality of selectively activatable filtering screens to progressively reduce the light intensity of the emitted beam. In this case, maximum beam intensity is achieved when no filtering screens are activated.

[0024] In one embodiment, said one or more sensors may comprise at least one camera for detecting an image of the scene ahead of the vehicle and the electronic controller may be configured to process image data from said camera to estimate, at a given instant, the distance separating the vehicle from tunnel entrance or exit and consequently compute, also based on current vehicle speed, the time needed to reach tunnel entrance or exit. The sensors may also include for example a radar sensor and / or a lidar sensor and / or a sensor of the vehicle's geographical position associated with a satellite navigation system.

[0025] The invention also relates to the control method implemented by the system described above.

[0026] Detailed description of the invention

[0027] Further features and advantages of the invention will emerge from the following description with reference to the attached drawings, provided by way of non-limiting example, wherein:

[0028] - Figure 1 is a schematic side view illustrating a tunnel section and vehicles proceeding through the tunnel, near tunnel entrance and exit, with a diagram of the light intensity variation of the beam emitted by the rear lights of a vehicle according to the invention traversing the tunnel, and

[0029] - Figure 2 is a schematic top view of a vehicle according to the invention.

[0030] Figure 1 illustrates a vehicle A according to the invention traveling through a tunnel 1 and followed by a vehicle B. Figure 1 shows vehicles A, B both in the condition where they are near tunnel entrance 1A and in the subsequent condition where vehicles A, B are near tunnel exit 1 B. Arrows D indicate the direction of movement of vehicles A, B through tunnel 1 .

[0031] According to the invention, vehicle A is equipped with a driving assistance system that automatically varies the light intensity of the beam emitted by vehicle As rear lights during passage through tunnel 1 .

[0032] The diagram at the bottom of Figure 1 shows an example of the light intensity variation of the beam emitted by vehicle As rear lights according to the invention. In this diagram, the minimum value of the light intensity of vehicle As rear lights' beam, indicated with N, corresponds to a predetermined nominal value, substantially equal to the light intensity of the beam emitted by a conventional vehicle's rear light. The diagram in Figure 1 refers to the light intensity of the beam emitted by each position light of the vehicle. Naturally, a similar diagram can be considered for the light intensity of the beam emitted by the vehicle's stop lights and rear fog lights.

[0033] According to the invention, when vehicle A is at tunnel entrance 1A, the driving assistance system automatically brings the light intensity of the beam emitted by the vehicle's rear lights (in the illustrated case, for example, the vehicle's position lights) to a maximum value M1 , significantly higher than said predetermined nominal value N. Thus, when vehicle A according to the invention enters the tunnel, it immediately becomes more visible to following vehicle B. The driver of vehicle B can therefore detect the presence of vehicle A ahead, despite the critical condition due to the abrupt change in ambient lighting near tunnel entrance 1 A.

[0034] Again referring to the diagram at the bottom of Figure 1 , once vehicle A according to the invention has entered the tunnel, the light intensity of the beam emitted by the vehicle's position lights is gradually decreased until returning to predetermined nominal value N after a determined time interval, when vehicle A has traveled a length L1 of tunnel 1 .

[0035] The driving assistance system equipped on the vehicle according to the invention maintains the light intensity of the beam emitted by the vehicle's rear lights at predetermined nominal value N when vehicle A travels the central section of the tunnel, since it is presumed that in this condition the eyes of drivers of vehicles traveling through the tunnel have by now adapted to the different lighting condition.

[0036] The driving assistance system equipped on the vehicle according to the invention proceeds to increase again the light intensity of the beam emitted by the rear lights of vehicle A, starting when vehicle A is at a distance L2 from exit 1 B of tunnel 1 . The light intensity of the beam emitted by the position lights of vehicle A is increased again until reaching a maximum value M2 when vehicle A is at exit 1 B. The value M2 may be equal to value M1 or may also be different, and in particular may be lower than M1 , given that the difficulties for drivers' eyes in adapting to the different illumination are greater at tunnel entrance compared to tunnel exit. In any case, even at tunnel exit, the light intensity of the beam emitted by the position lights of vehicle A according to the invention is higher than nominal value N, so that a vehicle B following vehicle A is perfectly capable of detecting the presence of vehicle A, despite the critical condition due to the change in ambient illumination level.

[0037] Naturally, the above applies to the vehicle's position lights and / or the vehicle's stop lights and / or the vehicle's rear fog lights.

[0038] As already indicated, to achieve variation of the light intensity of the beam emitted by the vehicle's rear lights, the lights may be arranged according to various alternative embodiments. For example, each rear light may include a plurality of selectively activatable light sources to vary the total light intensity of the beam emitted by the sources. Alternatively, the rear lights may include light sources provided with an electronic control unit configured to make said light sources emit a light beam with variable intensity, depending on a signal (e.g., a current signal) sent to the electronic control unit. Or, light sources may be provided with a plurality of selectively activatable filtering screens to progressively reduce the light intensity of the beam emitted by said light sources.

[0039] Figure 2 schematically illustrates a vehicle A according to the invention. In this example, vehicle A includes left and right position lights P1 , P2, left and right stop lights Q1 , Q2 (and a third stop light, not shown) and left and right rear fog lights R1 , R2. The lights P1 , Q1 , R1 and R2, Q2, P2 are controlled by electronic boards E1 , E2. In the example, the lights have light sources capable of emitting a light beam with intensity variable according to a current signal emitted by the respective electronic board E1 , E2. The electronic boards E1 , E2 are in turn controlled by an electronic controller E of the vehicle which also receives data from one or more sensors, schematized in the example as a single sensor S, whose function will be described below. The electronic controller E also receives a signal S1 indicative of the speed of vehicle A from the vehicle's electronic control unit (ECU).

[0040] The sensor S is a sensor of any known type (e.g. a camera, or a radar, or a lidar) capable of detecting both a first condition where the vehicle is about to enter a tunnel and a second condition where the vehicle is about to exit a tunnel. For example, sensor S may be capable of detecting the distance separating the vehicle from entrance 1A or exit 1 B of tunnel 1 (figure 1 ). Alternatively, or in addition, a sensor may be provided consisting of a sensor of the vehicle's geographical position forming part of a satellite navigation system.

[0041] The distance of the vehicle from the tunnel entrance, or from the tunnel exit, may be estimated by the electronic controller E, in one embodiment, by monitoring the variation of the angle at which sensor S sees the side walls of the tunnel entrance or exit, said angle progressively increasing as the vehicle approaches the tunnel entrance or exit. The electronic controller E is configured to receive data from sensor S (or from multiple sensors S) and process said data, also based on signal S1 indicative of the vehicle's speed, to obtain predictive information about the time needed to reach entrance 1A of tunnel 1 , when the vehicle is in said first condition, and the time needed to reach exit 1 B of tunnel 1 , when the vehicle is in said second condition.

[0042] The electronic controller E may accordingly send a command to electronic boards E1 , E2 to bring the light intensity of the beam emitted by the vehicle's rear lights to maximum value M1 (figure 1 ) when vehicle A is at entrance 1 A of tunnel 1 , after which the electronic controller E proceeds to progressively reduce the light intensity of the beam emitted by the rear lights until returning it to nominal value N after a determined time interval following tunnel entry, corresponding to a distance L1 traveled by the vehicle. Similarly, the electronic controller E is capable of monitoring the distance of vehicle A from exit 1 B of the tunnel while vehicle A travels through the tunnel, so it is capable of commanding another increase in the intensity of the light beam emitted by the vehicle's rear lights starting when vehicle A is at a distance L2 from exit 1 B of the tunnel until when vehicle A is at exit 1 B, where the light intensity reaches maximum value M2. Once vehicle A has exited the tunnel, the electronic controller E proceeds to return the light intensity of the beam emitted by the vehicle's rear lights (when they are activated) to nominal value N.

[0043] The electronic controller E may be configured to implement said variations in the light intensity value of the vehicle's rear lights from maximum value M1 to nominal value M at tunnel entrance, and from nominal value M to maximum value M2 at tunnel exit, depending on a determined traveled distance L1 , L2, or depending on a determined time interval. Naturally, if during the variation from maximum value M1 to nominal value N the vehicle is already near the tunnel exit, the decrease in light intensity is interrupted to increase it again to value M2.

[0044] It may also be provided that, if at tunnel entrance it is determined that the distance to tunnel exit is less than a predetermined minimum value, the electronic controller maintains the light intensity of the rear lights at said maximum value M1 for the entire length of the tunnel.

[0045] As is evident from the foregoing, thanks to the invention, the risk that a vehicle equipped with the system described here may be hit by a following vehicle traveling at higher speed is drastically reduced, in the critical visibility conditions occurring at tunnel entrance and exit. The system according to the invention is therefore particularly advantageous if installed on heavy transport vehicles, which often find themselves crossing a tunnel at low speed and not being seen by passenger cars following at higher speed that are about to enter the tunnel. The applicability of the invention is however, as is evident, completely general.

[0046] Naturally, while maintaining the principle of the invention, the construction details and embodiments may vary widely with respect to what has been described and illustrated purely by way of example, without thereby departing from the scope of the present invention, as defined in the appended claims.

Claims

CLAIMS1.A vehicle, comprising one or more rear lights, including position lights (P1 , P2), stop lights (Q1 , Q2), and, preferably, also rear fog lights (R1 , R2), wherein at least part of said rear lights include:- a plurality of light sources, selectively activatable to vary the total light intensity of the emitted light beam, or- one or more light sources, provided with an electronic control unit (E1 , E2), configured to make said light sources emit a light beam having an intensity variable according to a signal sent by the electronic control unit (E1 , E2), or:- one or more light sources, provided with a plurality of selectively activatable filtering screens, to progressively reduce the light intensity of the light beam emitted by said light sources, wherein said vehicle comprises a driving assistance system including:- one or more sensors (S) for detecting a first condition where the vehicle (A) is about to enter a tunnel (1 ) or a second condition where the vehicle is about to exit a tunnel (1 ), and- an electronic controller (E) configured to receive data from said one or more sensors (S) and process said data, also based on data (S1 ) relating to the vehicle's speed, to obtain predictive information about the time needed to reach the entrance (1A) of a tunnel (1 ), when the vehicle is in said first condition, or the time needed to reach the exit (1 B) of a tunnel (1 ) when the vehicle is in said second condition, and wherein the electronic controller (E) is programmed to:- bring the light intensity of the beam emitted by each rear light to a maximum value (M1 ), significantly higher than a predetermined nominal value (N), at the instant when the vehicle (A) enters a tunnel (1 ) and at the instant when the vehicle (A) exits the tunnel (1 ),- progressively decrease the light intensity of the beam emitted by each rear light, from said maximum value (M1 ) to said predetermined nominal value (N) for a determined time interval after entering a tunnel (1 ),- progressively increase the light intensity of the beam emitted byeach rear light, from said predetermined nominal value (N) to a maximum value (M2) for a determined time interval before the instant when exit from the tunnel (1 ) is expected,- return the light intensity of the beam that can be emitted by each rear light to said predetermined nominal value (N) after exiting the tunnel.

2. Vehicle according to claim 1 , wherein said one or more sensors (S) comprise at least one camera for detecting an image of the scene ahead of the vehicle (A), and wherein said electronic controller (E) is configured to process image data from said camera (S) to estimate, at a given instant, the distance separating the vehicle (A) from the entrance (1 A), or from the exit (1 B), of a tunnel (1 ) and consequently compute, also based on the current speed of the vehicle, the time needed to reach the entrance, or the exit, of the tunnel.

3. Vehicle according to claim 1 , wherein said one or more sensors comprise a radar sensor and / or a lidar sensor and / or a sensor of the vehicle's geographical position associated with a satellite navigation system.

4. Vehicle according to claim 1 , wherein the electronic controller (E) is configured such that, if during the phase in which the intensity of the beam emitted by each rear light is progressively decreased, after entering the tunnel, it is detected that the tunnel exit is so close as to require initiating the phase of increasing the light intensity, the phase of decreasing the light intensity is interrupted and the phase of increasing the light intensity is immediately started.

5. Vehicle according to claim 1 , wherein the electronic controller is configured such that if upon entering the tunnel it is determined that the distance to the tunnel exit is less than the predetermined minimum value, the electronic controller maintains the light intensity of the rear lights at said maximum value (M1 ) from when the vehicle enters the tunnel until when the vehicle exits the tunnel.

6. Method for controlling the rear lights of a vehicle, wherein at least some of said rear lights each include:- a plurality of selectively activatable light sources to vary the total light intensity of the light beam emitted by each of said rear lights, or:- one or more light sources provided with an electronic control unit(E1 , E2) configured to make said light sources emit a light beam having an intensity variable according to a signal sent by the electronic control unit (E1 , E2), said method comprising the operations of:- detecting, via one or more sensors (S), a first condition where the vehicle (A) is about to enter a tunnel (1 ) and a second condition where the vehicle (A) is about to exit a tunnel (1 ),- receiving, in an electronic controller, data from said one or more sensors (S) and processing, via said electronic controller (E), said data, also based on data (S1 ) relating to the vehicle's speed, to obtain predictive information about the time needed to reach the entrance (1A) of a tunnel (1 ), when the vehicle (A) is in said first condition, or the time needed to reach the exit (1 B) of a tunnel (1 ) when the vehicle is in said second condition, and performing, via the electronic controller (E), the following operations:- bringing the light intensity of the beam emitted by each rear light to a maximum value (M1 ), significantly higher than a predetermined nominal value (N), at the instant when the vehicle (A) enters a tunnel (1 ) and at the instant when the vehicle (A) exits a tunnel (1 ),- progressively decreasing the light intensity of the beam emitted by each rear light, from said maximum value (M1 ) to said predetermined nominal value (N) over a determined time interval after the vehicle (A) enters the tunnel,- progressively increasing the light intensity of the light beam emitted by each rear light, from said predetermined nominal value (M) to a maximum value (M2) over a determined time interval before the instant when exit from the tunnel is expected, and- returning the light intensity of the beam that can be emitted by each rear light to said predetermined nominal value, after exiting the tunnel.

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