GB2380250A

GB2380250A - Deceleration warning device for motor vehicles

Info

Publication number: GB2380250A
Application number: GB0123116A
Authority: GB
Inventors: Bernhard Boll
Original assignee: LuK Lamellen und Kupplungsbau Beteiligungs KG; LuK Lamellen und Kupplungsbau GmbH
Current assignee: Schaeffler Buehl Verwaltungs GmbH; LuK Lamellen und Kupplungsbau GmbH
Priority date: 2001-09-26
Filing date: 2001-09-26
Publication date: 2003-04-02
Anticipated expiration: 2021-09-26
Also published as: GB2380250B; GB0123116D0; DE10241480A1

Abstract

A warning system for a motor vehicle comprises means (19a,30,42,34,32,26,64) for monitoring deceleration of the vehicle, warning lights (72) visible from the exterior of the vehicle and means (36) for automatically illuminating the warning lights (62,64) when deceleration of the vehicle exceeds a predetermined limit and the vehicle brakes (70) are not applied. The warning lights may be the brake lights (72) and/or hazard warning lights (74) already fitted to the vehicle. The deceleration may be monitored through gear selection and vehicle and engine speeds, clutch torque, gearbox shaft speed, or an accelerometer.

Description

VEHICLE WARNING SYSTEMS The present invention relates to vehicle warning systems and in particular to systems for warning other road users of the rapid deceleration of a vehicle.

When a vehicle decelerates due to the application of the brakes of the vehicle, a warning is given to vehicles following, by means of the brake lights. However, if a vehicle decelerates without application of the brakes, no warning is given. This may be particularly hazardous where the deceleration is unexpected by the vehicle driver and he is unable to warn other road users, by applying the brakes to activate the brake lights.

This is a particular problem with automated manual or semi-automated transmission systems where the driver may inadvertently select a lower gear than intended, or a system fault may result in rapid deceleration of the vehicle.

According to one aspect, the present invention provides a warning system comprising means for monitoring deceleration of the vehicle, warning lights visible from the exterior of the vehicle and means for automatically illuminating the warning lights when deceleration of the vehicle exceeds a predetermined limit and the vehicle brakes are not applied.

According to a preferred embodiment of the invention, the warning lights may be the brake lights or hazard warning lights conventionally provided on a motor vehicle.

According to a further embodiment of the invention, the intensity of illumination of the warning lights may be varied, depending on the rate of deceleration and/or in order to differentiate between illumination of the brake lights in accordance with the present invention or illumination of the brake lights due application of the brakes.

In accordance with the present invention, deceleration of the vehicle may be measured by :- a) using the gradient of wheel speed signal from wheel sensors of a vehicle anti-lock braking or similar systems; b) measuring clutch torque during re-engagement of the clutch after gear shifting; c) by predicting deceleration, knowing the target gear, vehicle speed and engine speed; or d) by means of an accelerometer.

An embodiment of the invention is now described, by way of example only, with reference to Figure 1, which illustrates diagrammatically a semi-automated transmission system for a motor vehicle.

Figure 1 shows an engine 10 with a starter and associated starter circuit 10a which is coupled through the main drive friction clutch 14 to a multispeed synchromeshed lay shaft-type gearbox 12, via a gearbox input shaft 15. Fuel is supplied to the engine by a throttle 16 which includes a throttle valve 18, operated by accelerator pedal 19. The invention is equally applicable to electronic or mechanical fuel injection petrol or diesel engine.

The clutch 1 4 is actuated by a release fork 20 which is operated by a hydraulic slave cylinder 22, under the control of a clutch actuator control means 38.

A gear selector lever 24 operates in a gate 50 having two limbs 51 and 52 joined by a cross track 53 extending between the end of limb 52 and intermediate of the ends of limb 51. The gate 50 defines five positions; "R"at the end of limb 52 ;"N"intermediate of the ends of the cross track

53 ;"S"at the junction of limb 51 with the cross track 53; and +"and "-"at the extremities of limb 51. In limb 51 the lever 24 is biased to the central"S"position. The"N"position of the selector lever 24 corresponds to neutral ;"R"corresponds to selection of reverse gear ;"S" corresponds to selection of a forward drive mode; momentary movement of the lever to the +"position provides a command to cause the gearbox to shift up one gear ratio; and momentary movement of the gear lever 24 to the"-"position provides a command to cause the gearbox to shift down one gear ratio.

The positions of the lever 24 are sensed by a series of sensors, for example micro switches or optical sensors, positioned around the gate 50. Signals from the sensors are fed to an electronic control unit 36. An output from the control unit 36 controls a gear engaging mechanism 25, which engages the gear ratios of the gearbox 12, in accordance with movement of the selector lever 24 by the vehicle operator, for example as disclosed in GB2308413; GB2354295; GBOO03698. 8; GB0100569. 3; GB0105186. 1, whose content is expressly incorporated in the disclosure content of the present application.

In addition to signals from the gear selector lever 24, the control unit 36 receives signals from: sensor 1 9a indicative of the degree of depression of the accelerator pedal 19; sensor 30 indicative of the degree of opening of the throttle control valve 18; sensor 26 indicative of the engine speed; sensor 42 indicative of the speed of the clutch driven plate ; sensor 34 indicative of the clutch slave cylinder position; and sensor 32 indicative of the gear ratio selected.

The control unit 36 utilises the signals from these sensors to control actuation of the clutch 14 during take-up from rest and gear changes, for example as described in patent specifications EP003811 3, EP0043660, EP0059035, EP0101220 and W092/13208 whose content is expressly incorporated in the disclosure content of the present application.

In addition to the above mentioned sensors, control unit 36 also receives signals from a vehicle speed sensor 64 and/or wheel speed sensor 66 and brake switch 68 associated with the main braking system, for example the foot brake 70 of the vehicle.

A buzzer 62 is connected to the control unit 36 to warn/indicate to the vehicle operator as certain operating conditions occur. In addition or in place of the buzzer 62 a flashing warning light or other indicating means may be used. A gear indicator 60 is also provided to indicate the gear ratio selected.

An output from the control unit 36 is also connected to the vehicle brake light circuit 72 and/or the vehicle hazard warning light circuit 74.

In the case of a malfunction of the automated control of the clutch 14 or gear selection mechanism 25, the control unit 36 may disable the transmission system or may restrict operation thereof to, for example the selection of certain gear ratios only. Such operation may result in significant deceleration of the vehicle.

In accordance with one aspect of the invention, upon detection of a malfunction, the control unit 36 generates a signal to energise the brake light circuit 72 and/or the hazard warning light circuit 74 of the vehicle, to illuminate the brake lights and/or hazard warning lights and thereby provide a warning to other road users.

Furthermore, it is possible with automated manual or semi-automatic transmission systems of the type disclosed ; for the driver of the vehicle to inadvertently engage a gear ratio that is lower than that intended, thereby causing the vehicle to decelerate under engine braking; or to engage a gear higher than intended thereby causing the engine to stall. Under such circumstances, from the gear engaged as indicated by sensor 32, the engine speed as indicated by sensor 26 and the road speed as indicated by sensor 64 or wheel speed sensor 66, the control unit 36 may predict the rate of deceleration of the vehicle and, if this exceeds a predetermined value and the brake light switch 68 is open, control unit 36 may again energise the brake light circuit 72 and/or the hazard warning light circuit 74 of the vehicle, to provide a warning.

Alternatively, from the rate of change of speed of the gearbox input shaft 15, from sensor 42, the control unit 36 can determine the torque applied to the clutch 14 during re-engagement of the clutch 14 after gear shifting.

If the torque level is above a predetermined value, indicating a rapid deceleration of the vehicle, then if the brake 70 is not already applied, the control unit 36 can again energise the brake light circuit 72 and/or hazard warning light circuit 74.

According to further alternative embodiments, the control unit 36, or a hazard warning system control unit separate from control unit 36, may use the vehicle speed sensor 64, wheel speed sensor 66 or an accelerometer, to determine the deceleration of the vehicle and, if the deceleration exceeds a predetermined limit, and the brake 70 is not applied, energise the brake light circuit 72 and/or hazard warning light circuit 74.

In order to differentiate between actuation of the brake lights under normal braking and in accordance with the present invention, the brake light circuit 72 when energised in accordance with the present invention may be arranged to :-

a) illuminate the brake lights at a different intensity that when illuminated under normal braking, for example by reducing or increasing the energising current; b) causing the brake lights to flash by pulsing the energising current; and/or c) illuminating the hazard warning lights simultaneously with the brake lights.

While the embodiment described above relates to an automated transmission system, the present invention may also be applied to deceleration of the vehicle due to the malfunctioning of other systems, for example the engine management system.

The patent claims submitted with the application are proposed formulations without prejudice to the achievement of further patent protection. The applicant reserves the right to submit claims for further combinations of characteristics, previously only disclosed in the description and/or drawings.

References back used in sub-claims refer to the further development of the subject of the main claim by the characteristics of the respective subclaim ; they are not to be understood as a waiver with regard to achieving independent item protection for the combination of characteristics in the related sub-claims.

Since the subject of the sub-claims can form separate and independent inventions with reference to the prior art on the priority date, the applicant reserves the right to make them the subject of independent claims or of division declarations. Furthermore, they may also contain independent inventions which demonstrate a design which is independent of one of the objects of the preceding sub-claims.

The embodiments are not to be considered a restriction of the invention.

Rather, a wide range of amendments and modifications is possible within the scope of the current disclosure, especially those variations, elements and combinations and/or materials which, for example, the expert can learn by combining individual ones together with those in the general description and embodiments in addition to characteristics and/or elements or process stages described in the claims and contained in the drawings with the aim of solving a task thus leading to a new object or new process stages or sequences of process stages via combinable characteristics, even where they concern manufacturing, testing and work processes.

Claims

CLAIMS.

1. A warning system for a motor vehicle comprising means for monitoring deceleration of the vehicle, warning lights visible from the exterior of the vehicle and means for automatically illuminating the warning lights when deceleration of the vehicle exceeds a predetermined limit and the vehicle brakes are not applied.

2. A warning system according to claim 1 in which the warning lights are the brake lights and/or hazard warning lights conventionally provided on the motor vehicle.

3. A warning system according to claim 2 in which the brake lights are illuminated at different intensity than when illuminated by normal application of the brakes.

4. A warning system according to claim 2 or 3 in which the brake lights are flashed.

5. A warning system according to any one of claims 2 to 4 in which the brake lights and hazard warning lights are illuminated simultaneously.

6. A warning system according to any one of the preceding claims in which means is provided to predict the deceleration and to illuminate the warning lights when the predicted deceleration exceeds the predetermined value.

7. A warning system according to claim 6 in which means is provided for monitoring a target gear, the vehicle speed and the engine speed, the deceleration being predicted from the target gear, vehicle speed and engine speed.

8. A warning system according to any one of claims 1 to 5 in which deceleration is measured by measuring clutch torque during reengagement of the clutch after a gear shift.

9. A warning system according to claim 8 in which means is provided to monitor the speed of an input shaft of a gearbox of the vehicle, clutch torque being measured by monitoring the rate of change of speed of the gearbox input shaft.

10. A warning system according to any one of claims 1 to 5 in which sensors are provided for monitoring the wheel speed of the vehicle, deceleration being measured by measuring the rate of change of wheel speed.

11. A warning system according to any one of claims 1 to 5 in which deceleration is measured by means of an accelerometer.

12. A warning system for a motor vehicle substantially as disclosed herein, with reference to and as shown in figure 1.