GB2186131A

GB2186131A - Vehicle braking indicator-lamp controller responsive to hazardous conditions

Info

Publication number: GB2186131A
Application number: GB08701924A
Authority: GB
Inventors: L A Birt
Original assignee: BIRT ELECTRONIC SYSTEMS LIMITE
Current assignee: BIRT ELECTRONIC SYSTEMS LIMITE
Priority date: 1986-01-29
Filing date: 1987-01-28
Publication date: 1987-08-05
Anticipated expiration: 2007-01-28
Also published as: GB8701924D0; GB2186131B

Abstract

A controller monitors (on inputs WS or RFLS) if either the windscreen wipers or rear fog lights of a vehicle are energised (indicative of hazardous visibility driving conditions) and further monitors (on input BLS) for application of the footbrake whilst either the wipers or rear fog lights are energised, to actuate rear lights of the vehicle over output RFL. This provides a distinctive warning indication at the rear of the vehicle and during poor visibility conditions that the vehicle is braking. The output RFL may cause the rear fog lights to be pulsed. If the brakes remain energised for longer than a period set by a relay generator 4, the pulsing ceases. The controller may also monitor (on input RTIS) operation of the right-turn indicator switch (for a RHD vehicle) so that if the brakes remain energised for longer than the delay of generator 4 whilst that turn switch is operated, the rear fog lights are pulsed. A rear light or lights other than the fog lights may be actuated by the controller and may be turned on continuously, or pulsed, in the above situations. The controller may be implemented in micro-processor form, (Fig. 2). <IMAGE>

Description

SPECIFICATION Automatic high intensity braking indicatorlamp controller for vehicles This invention relates to a controller for supplementary braking indicator lamps on vehicles, operating automatically to cause these lamps to provide a high intensity indication in the event of braking, so as to provide a sure warning to the driver of any following vehicle and thereby enhance safety on the road.

The "rear end" type of impact is all too common on the road, particularly on motorways and other fast roads and particularly in hazardous driving conditions e.g. fog, spray and darkness. Often for example the driver is confronted with an indistinct and bewildering panorama of rear lights, rear fog lights, indicators, hazard warning lights and oncoming headlights. Against this general background, it frequently occurs that the driver fails to notice or react quickly to conventional brake lights being illuminated on the vehicle or vehicles in front. This, can all too easily result in a serious "rear end" impact, the extended reaction time plus the braking time determining a stopping distance which is greater than the distance to the vehicle in front.In effect, the extended reaction time is due to a form of information overload on the driver, namely the quantity, clarity and varying form of lights confronting the driver seriously delay him reacting to the normal brake lights illuminating on the vehicle ahead. The "rear end" type of impact is particularly common on motorways for example, in high traffic density, high speed, hazardous visibility (e.g. due to spray, fog and driving rain) and contra-flow conditions.

In accordance with this invention there is provided a controller for one or more rear lights of a vehicle, which controller monitors if either the vehicle windscreen wipers or the rear fog lights are energised, and further monitors for application of the footbrake, whilst either the wipers or rear fog lights are energised, to actuate said one or more rear lights so as to provide a warning indication.

Hazardous visibility conditions ,e.g. wet or fog, will cause the driver to switch on the windscreen wipers and/or the rear fog lights.

Then, when he brakes, the controller automatically actuates said one or more rear lights.

The controller may actuate the vehicle's rear fog lights, which are now a statutory requirement on modern vehicles, by pulsing them on and off. Instead, some other light or lights may be provided to the rear of the vehicle and either pulsed or energised continuously.

The controller may form a unit readily and simply fitted to existing road vehicles, or to vehicles at manufacture.

Typically the controller may pulse said one or more rear lights on and off at approximately 120 (and in general 90-150) flashes per minute. Preferably the controller is arranged so that, should the brakes be held on for an extended period of time (say 10-15 seconds), the flashing or other actuation will cease and the lights restored to their previous condition. This will prevent annoyance to the driver of the following vehicle, particularly in a stationary queue of traffic. However, the controller will cause the flashing or other actuation to commence again if the brakes are released and then reapplied.

Preferably also the controller is arranged to monitor the operation of the right-turn indicator (or left-turn indicator in the case of left hand drive vehicles): if the brakes have been applied for an extended period of time (say 10-15 seconds) whilst the right turn indicator is operating, then the controller automatically actuates said one or more rear lights (whether or not the wipers or rear fog lights are otherwise energised). This provides a distinctive warning of a stationary vehicle waiting in the middle of the road to rurn right.

Embodiments of this invention will now be described by way of examples only and with reference to the accompanying drawing, in which: Figure 1 is a block diagram of a controller in accordance with the invention; and Figure 2 is a block diagram of a corresponding microprocessor implementation of the controller.

In the example of controller unit shown in Fig. 1, signals RFLS and WS from a rear fog light switch and the wipers switch, respectively, are applied to inputs A, B of an OR gate 1. A signal BLS from the brake light switch is applied to an input E of an AND gate 2. Operation of the wiper switch applies a high to input B of OR gate 1, in turn providing a high at its output C and this is applied to an input D of AND gate 2. If then the brakes are applied, a high is applied to input E of AND gate 2 and to input H of a delay generator 4. Input G of AND gate 2 is normally high (being the untriggered state of output J of delay generator 4). Input F of AND gate 2 alternates between high and low logic levels at a rate determined by a square wave generator 3-typically 0.25 sec ON/0.25 sec OFF.

Thus, under the above circumstances of the brakes being applied whilst the wipers are on, inputs D, E, F and G of AND gate 2 combine together to produce an alternating high/low logic output (at K). This pulsing output is applied to input M of an exclusive OR gate 5 and transmitted from output N of this gate, through an exclusive OR gate 11 and to input S of a power switch 7: this power switch feeds power to the rear fog lamps over line RFL and thus these rear fog lamps produce a pulsing, high intensity beam of light.

Should the brakes be held for an extended period of time (say 10-15 seconds) determined by the delay generator 4, at the end of this period a low output will issue at J for the application to input G of AND gate 2, inhibiting the latter and causing K to revert to low and switch the rear fog lamps off. The delay generator is reset when the brakes are released.

Operations of the rear fog light switch applies a high to input L of exclusive OR gate 5, in turn to apply a high through exclusive OR gate 11 and to input S of the power switch 7, to switch the rear fog lamps on continuously. Then if the brakes are applied, output K of AND gate 2 will alternate between high and low levels exactly as described above and giving an alternating signal on the input M of exclusive OR gate 5. This gate responds to the alternating input M and the high at L to produce an alternating output at N, which is applied via exclusive OR gate 11 to the power switch, causing the rear fog lights to be pulsed. Extended application of the brakes will produce the same effect from the delay generator 4 as previously described.

Operation of the right-turn indicator switch (left-turn indicator switch in the case of lefthand drive vehicles) causes a high to be applied to input V of an AND gate 10. Extended application of the brakes (for say 10-15 seconds) as determined by the delay generator 4 triggering, produces a low at J and this is applied to an input T of an inverter 8, providing a high at its output U for application to input I of AND gate 10. Inputs 0, I and V combine together to produce an alternating high/low at output W of the AND gate 10: this is applied through exclusive OR gate 11 to power switch 7 in order to pulse the rear fog lights. This effect is produced whether or not the rear fog lamps switch is already operated, as a result of the combination of inputs X and Y of exclusive OR gate 11.

It will be noted that the logic circuit described allows correct operation for all combinations of the rear fog lights, wipers, turn indicator and brake light switches.

The circuit may be modified so that, whilst still monitoring for application of the brakes whilst either the rear fog lights or the windscreen wipers are operating, it will cause some rear light or lights (other than the rear fog lights) to be pulsed in the manner described above, instead of the rear fog lights.

The circuit comprises a relatively few interconnected logic elements and thus entails low manufacturing costs. The unit will thus contribute significantly to road safety. The design can be implemented cost-effectively in discrete logic with standard logic integrated circuits, custom or semi-custom logic integrated circuits (custom/programmable gate array devices) or single-chip or multi-chip microprocessor integrated circuits.

Instead of the hardware logic implementation which has been illustrated and described, the invention may be implemented in a microprocessor system arranged to perform all the same functions and this is shown in Fig. 2.

Here, the microprocessor 20 is shown with Read Only Memory 21 holding a software program to implement the same logic functions as the controller of Fig. 1. A Random Access Memory for the microprocessor is also shown: two programmable input/output integrated circuits 23, 24 are provided, the first for receiving the signals RFLS, WS, BLS and RTIS and the other providing a control signal to the power switch 7.

Instead of pulsing the rear fog lights or some other rear light or lights of the vehicle, the controller may serve to energise some rear light or lights continuously in order to provide the warning indication. The circuit shown in Fig. 1 may readily be modified for this by arranging generator 3 to provide a continuous high signal to the AND gates 2 and 10.

Claims

1. A controller for one or more rear lights of a vehicle, which controller monitors if either the vehicle windscreen wipers or the rear fog lights are energised, and further monitors for application of the footbrake, whilst either the wipers or rear fog lights are energised, to actuate said one or more rear lights so as to provide a warning indication.

2. A controller as claimed in Claim 1, arranged so that should the brakes be held on for a predetermined period of time, said actuation of said one or more rear lights ceases and those lights are restored to their previous condition.

3. A controller as claimed in Claim 2, in which said predetermined period of time is 10-15 seconds.

4. A controller as claimed in Claim 1, 2 or 3, arranged to monitor for operation of the right-turn indicator (or left-turn indicator in the case of a left-hand drive vehicle) and, if the brakes have been applied for a second predetermined period of time, to cause actuation of said one or more rear lights.

5. A controller as claimed in Claim 4, in which said second predetermined period of time is 10-15 seconds.

6. A controller as claimed in any preceding claim, arranged to actuate said one or more rear lights by pulsing them on and off.

7. A controller as claimed in Claim 6, in which said one or more lights which the controller is arranged to pulse are the rear fog lights of the vehicle.

8 A controller for one or more rear lights of a vehicle said controller being substantially as herein described with reference to Fig. 1 or Fig. 2 of the accompanying drawings.

9. In or for a vehicle, an electrical system comprising a controller as claimed in any preceding claim, said controller having inputs connected to the windscreen wipers switch, the rear fog lights switch and the footbrake switch, and an output connected to actuate said rear fog lights or one or more other rear lights of the vehicle, so as to provide a warning indication.