FR2516032A1 - Automatic headlamp dipping circuit for motor vehicle - uses optical detector receiving light from headlamps of oncoming vehicle to switch headlamps to dipped beam - Google Patents

Abstract

An optical transducer (1) receives light rays (R) emitted by the head lamps of the oncoming vehicle, and generates a signal which is applied to a threshold circuit (2) coupled to an amplifier and shaping circuit (3). The output from this last circuit controls a switching circuit (4) which switches the headlamps (6) between high beam and dipped beam. The threshold detector circuit (2) comprises a transistor (T) with the optical transducer (11) connected to its base terminal, and having one of the bias resistors (R2) adjustable to give an adjustable threshold. The changeover is obtained by a double relay, and full beam is automatically resumed upon crossing of the oncoming vehicle.

Description

 The present invention relates to a device for controlling the lighting of a vehicle, in particular an automobile.

 Indeed, it is increasingly observed that motorists who, for various reasons, travel with lights on in the "headlight" position remain in this position and thereby considerably hamper vehicles holding in the opposite direction.

The reasons for this neglect are diverse and come in part from increasingly complex road signs requiring constant attention, increasingly complex vehicle dashboards, comprising an increasing number of warning lights or warning lights, which do not more clearly, so apparently, the position called "headlights
The present invention aims to remedy these drawbacks and proposes to create a device for automatically switching the lighting from the "headlights" position to the "codes" position, when oncoming vehicles approach the limit at which switching must be made, according to road traffic rules, to avoid the dazzling of oncoming vehicles, etc., without however this switching eliminating the possibility of switching to a lighthouse for example by headlight call control, in the event of dangerous situations requiring instantaneously more intense lighting and at a greater distance than that of lighting by codes.

 To this end, the invention relates to an installation characterized in that it comprises an optical sensor receiving the light radiation emitted by the lights of the oncoming vehicle to attack a threshold circuit connected to an amplification and setting circuit. in the form of the signal used to control an automatic switching circuit for controlling the supply of the code lights if the manual switching device is in the "headlight lights" position and the sensor receives a sufficient lighting signal.

 Thus, thanks to the installation, the driver remains in control of the choice of lighting mode (headlights / codes) at least for the transition from the "codes" position to the "headlights" position or vice versa because he can continue to operate manually his order.

 When the driver chooses automatic operation, he puts the manual control device in the lighting position by the headlights, leaving it to the automatic control circuit to switch to the code position whenever necessary because of the arrival of oncoming vehicles, then the opposite switch is made once the vehicle passes.

 Indeed, the sensor no longer detecting an appropriate signal, the threshold circuit and the amplifier no longer provide a control signal for the automatic switching circuit which returns by itself to its first position.

 This headlight / code switching device can also be applied under analogous conditions, for switching switching between the "code" and "pilot" positions, by an appropriate choice of a sensor or by adjusting its threshold. The threshold adjustment for switching "headlights / codes" or for switching "codes / pilot lights" can be done at the same time as the driver puts, depending on the type of electrical installation of the vehicle, the lighting in the "pilot lights" position / codes "or in the" codes / headlights "position.

 This simplifies the automatic switching installation and limits it to a chain of signal processing.

 Depending on the sensitivity of the sensor, the circuit also makes it possible to avoid dazzling the driver of the vehicle in front. Indeed, i may happen that, as a result of an oversight, the driver who arrives quickly on a vehicle in front, forgets to switch from the "headlights" position to the "codes" position.

 The reflection of its light from the headlights on the bodywork of the preceding vehicle, in particular on the number plate, the bumper, etc.; can return a sufficient luminous flux to request the sensor so that it provides a sufficient signal to switch from the headlight position to the "codes" position.

 According to another advantageous characteristic, the threshold circuit has an adjustable threshold and in particular a circuit formed by a transistor, the base of which is connected to the junction point of the variable resistance of the optical sensor and of the adjustable resistance defining the sensitivity threshold of installation triggered.

 According to another advantageous characteristic, the automatic switching circuit is constituted by a double switch controlled by a control device receiving the signal from the sensor, after detection of threshold and amplification, the first switch being associated with the code lights for setting these implemented when the manual control device is in the headlight light supply position, the second switch being associated with the headlight lights, to cut off the power supply when the manual switching device is in the light position headlight, the switches being implemented when the threshold circuit detects lighting above the respective threshold.

 In general, the installation according to the invention is of a particularly simple embodiment and assembly. The installation can be fitted to vehicles, either as original equipment or as an accessory. This mounting as an accessory is also very simple since the number of connections to be made is reduced to a minimum.

 Furthermore, the installation according to the invention constituting an independent device, connected in a way in parallel to the manual control installation, the repairs are very simple in the event of a breakdown, by the replacement of the defective elements or even the restoration to temporary title of the original circuit, without automatic control.

The present invention will be described in more detail with the aid of the accompanying drawings, in which
- Figure 1 is an overall block diagram of the installation, the manual switch being in the "codes" position.

 - Figure 2 is a partial diagram corresponding to Figure 1, the manual switch being in the "headlights" position.

 According to Figure 1, the lighting control device of a motor vehicle, according to the invention, consists of a sensor 1, receiving the light radiation R from an oncoming vehicle, and providing a signal a threshold circuit 2 which, if necessary, provides a signal to an amplifier 3 supplying a control circuit 4 acting in parallel and in a complementary manner on the manual switching circuit 5 of the lighting installation 6 of the vehicle, the power supply being provided by a battery 7.

 According to the invention, the sensor 1 is, for example, constituted by a photoelectric sensor 11, carried by a support 12 allowing the orientation of the optical axis XX of the sensor 11, at a determined angle, corresponding to the detection of a vehicle when it enters the limit in which passing vehicles must only be lit by code lights. This sensor comprises a photosensitive element whose resistance varies as a function of the light received.

 The choice of the orientation of the axis X-X by -report to the support 12 depends on the position of the sensor 1 on the vehicle. The setting details are practical in nature and will not be described below.

 The sensor 1 is connected to a threshold circuit 2 which transmits a signal only if the signal supplied by the sensor 1 exceeds a certain threshold.

 For this, and as an example; the threshold circuit can be constituted by a comparator, such as a transistor T working in commutation. Such a transistor T is driven on its base by the series connection of the resistor R1 and of a variable resistor R2. The resistor R1 is the resistance of the sensor while the resistor R2 is a resistor strictly speaking part of the threshold circuit and whose adjustment makes it possible to define the triggering threshold of the transistor T.

The output of transistor T (collector) is connected to the junction of two other resistors R3, R4 connected in series between the two terminals of the power supply. The midpoint 21 provides the signal S1 which attacks the amplifier 3.

The amplifier 3 ensures the shaping and amplification of the signal S1 by conventional means not detailed to give a control signal S2 driving the automatic switching circuit 4. Schematically, the switching circuit 4 is constituted by a double relay
E1, E2 controlled by coil B.

 The switching control circuit 4 is connected to the manual control circuit or manual switch 5 ensuring the manual control of the lighting installation 6 for implementing either the "code" lighting C or the "headlight" lighting PH via the switch represented diagrammatically by a movable member 52 connected to an input terminal 51 and switching between an output terminal 53 and an output terminal 54.

 Terminal 51 is connected to terminal 71 of power supply 7, the other terminal 72 of which is connected to the second terminals of lighting devices C, PH.

 The automatic switching circuit 4 is made up of relays E1, E2, controlled by the coil B; this relay E1 is associated with the so-called "code" light C and the relay E2 is associated with the so-called "headlight" light PH.

 The relay E1 comprises an input terminal 41 connected to the terminal 51 of the device 5 as well as two output terminals 43, 44 and a movable member 42. The terminal 43 is not connected to any part of the electrical circuit. On the other hand, the fixed terminal 44 is connected to the terminal 53 ′, itself connected to the low beam C and to the terminal 53, in an equipotential manner.

 The relay E2 associated with the PH headlight comprises an input terminal 45 associated with the terminal 54 of the device 5 and two output terminals 47, 48; terminal 47 is connected to terminal 54 'of device 5, itself connected to high beam PH terminal 48 is not connected to any other part of the electrical circuit.

 In the position shown in Figure 1, the manual switching device 5 is switched to the position of code lights C, that is to say that the movable member 52 of the manual switching device 5, connects the terminal d 'input 51 to the output terminal 53 to supply the code C lights'

The circuit is thus established as follows between the terminals 71 and 72 of the power supply 7: 71, 51, 52, 53, 53 ', C, 72.

 In this position of the control 5, the installation and in particular the circuits 2, 3, 4 are not used, which makes it possible to cut them from the supply, for example by connecting the supply to the circuits 2, 3, 4 on terminal 54. Under these conditions, circuits 2, 3, 4 will only be supplied if the movable member 52 is switched on contact 54, that is to say if the control 5 is in the "headlights" position ".

 This second position and the function of the installation of the invention will be described with the aid of FIG. 2.

It should be noted that in the absence of current in the coil B, the relays E1, E2 are not switched and their movable members 42, 46 occupy the positions shown in solid lines in FIG. 2, and this is not that if circuit 4 receives a signal S2 which passes through coil B, that the relays
E1, E2 switch the members 42, 46 in the position shown in dotted lines; the members 42, 46 remain in this dotted position as long as the signal S2 is applied to the circuit 4. When the signal 52 disappears, that is to say when the sensor 1 no longer receives a sufficient light flux, the members 42, 46 return to the position in solid lines.

 In more detail, when the movable member of the device 5 occupies the position shown in FIG. 2, this normally corresponds to the supply position of the PH headlights which are connected to the terminals 71, 72 by the following circuit: 71, 51, 52, 54, 45, 46, 47, 54 ', PH, 72.

 The power supply for the code C lights is cut off since the mobile member 42 of the relay E1 is in contact with the free terminal 43.

 On the other hand, if the sensor 1 receives a light signal which the threshold circuit 2 considers to be sufficient, the amplifier 3 supplies a control signal S2 to the automatic control circuit 4 whose relay B controls the switching of the mobile members 42, 46 (position shown in dotted lines) which respectively come into contact with the terminals 44, 48.

 The power supply of the PH headlight lights is cut off since the movable member 46 touches the fixed contact 48 which is free and the code C lights are thus connected to the power supply 7 by the following path: 71, 51, 41, 42 , 44, 53 ', C 72.

 The switching control circuit 4 which has been described above in the case of two relays or a two-way double relay, could also be replaced by an electronic switching circuit, with fixed elements without mechanical contact, such as switching transistors controlled by a trigger signal S3.

 Likewise, and in general, the code C and PH headlight may be constituted each time by a set of code lights and headlight.

 The control device described above authorizes the control of the PH headlight lights by the headlight call control which is in parallel with the above control and which makes it possible to power the PH headlight lights even if the manual switching 5 or the automatic switching device 4 are switched to the "code lights" position.

 The installation according to the invention can be integrated into the electrical installation of a motor vehicle, either as original equipment, or be added to the already existing installation.

 In fact, the installation according to the invention consists, strictly speaking, of the sensor 1, of the threshold circuit 2 and of the amplifier 3 as well as of the automatic switching circuit 4.

 To connect the automatic control circuit 4, it is sufficient to cut off the supply of the headlight lights PH, of the original terminal 54 and to replace them with a branch connection by the terminals 45, 47 and 54 '.

 Similarly, it suffices to connect the fixed input terminal 51 to the fixed terminal 41. This connection can also be replaced by connecting the terminal 41 directly to the terminal 71.

 To simplify the description, the terminal 53 'is shown distinctly from the terminal 53. In reality, the terminals 53' and 53 which are equipotential can be merged into the same terminal.

 In general and as already indicated above, the automatic control installation operates in a reversible manner, that is to say both as described above and in reverse operation to restore the headlight lights, as soon as the oncoming vehicle was passed.

 Finally, it is possible to mount two sensors with two installations as described, or two sensors on one, operating circuit or even a single sensor and a two-threshold circuit, to control both the "headlights / codes" switching. and switching "codes / pilot lights", according to the manual switching position chosen by the user.

 Such a two-threshold control is particularly suitable for vehicles in which the lighting control is carried out in two stages, on the one hand, by a control button which makes it possible to choose between the "codes / pilot lights" lighting mode. or "codes / headlights" mode and; on the other hand, a joystick or a button which, inside each of the two above modes makes it possible to pass from one position to the other, that is to say from the position "pilot lights" a the "codes" position or from the "codes" position to the "headlights" position.

 In addition, to prevent the relays E1, E2 from switching too quickly from the "headlights" position to the "codes" position when the two vehicles cross, when the oncoming vehicle is closely followed by other vehicles, it is interesting to delay the supply of the coil B by a capacitor; when the signal S2 disappears, this capacitor discharges into the coil B preventing the immediate switching of the relays E1, E2. This delay can also be advantageous on a winding road, for example in the mountains, to avoid too frequent and inappropriate switching in the "headlight" position when cornering.

 This time delay is advantageously adjustable according to traffic conditions; it can also be deleted if necessary.

 In conclusion, even as a retrofit, the mounting of an installation according to the invention is extremely easy since it only involves a limited intervention at the level of the vehicle lighting control circuit.

Claims (4)

CLAIMS 1) Installation for controlling the lighting lights (code lights, headlight lights) of a motor vehicle, for automatically switching from the lighting position (headlights "to the lighting position" codes ", front and during a crossing maneuver with one or more oncoming vehicles, installation characterized in that it comprises an optical sensor (1) receiving the light radiation R emitted by the lights of the oncoming vehicle to attack a threshold circuit (2) connected to an amplification and shaping circuit (3) of the signal used to control an automatic switching circuit 4 for controlling the supply of the C code lights if the manual switching device (5) is in "headlight lights" position and the sensor (1) receives a sufficient light signal.  20) Installation according to claim 1, characterized in that the threshold circuit is a circuit (2) with adjustable threshold R2.  30) Installation according to claim 2, characterized in that the threshold circuit consists of a transistor circuit T whose base is connected to the junction point of the resistor R, the optical sensor (1 and an adjustable resistor R2 defining the threshold.  40) Installation according to any one of claims 1 to 3, characterized in that the automatic switching circuit (4) consists of a double switch E1, E2, controlled by a control device B receiving the signal S3 from the sensor ( 1), after threshold detection and amplification, one of the switches E1 being associated with the C code lights to implement these when the manual control device (5) is in the PH headlight lights supply position , the second switching device E2 being associated with the headlight lights PH, in order to cut off the supply thereof when the manual switching device (5) is in the headlight lights position, the two switching devices E1, E2 being implemented when the threshold circuit (2) detects a sufficient lighting signal supplied by the sensor (1).  50) Installation according to claim 4, characterized in that the automatic switching device (4) consists of a double relay.