GB2351328A

GB2351328A - Arrangement for indicating the need for a brake or tyre service

Info

Publication number: GB2351328A
Application number: GB9914562A
Authority: GB
Inventors: George Howard Mercer
Original assignee: MG Rover Group Ltd
Current assignee: MG Rover Group Ltd
Priority date: 1999-06-23
Filing date: 1999-06-23
Publication date: 2000-12-27
Also published as: GB9914562D0

Abstract

A brake service arrangement is provided within a motor vehicle 10. The arrangement includes a controller 1 arranged to receive dynamic signals from sensors 4 to 8 typically associated with other vehicle functional mechanisms such as for dynamic stability control. The controller 1 consolidates the dynamic signals received from the sensors 4 to 8 with known brake specification parameters, in order to provide a service requirement indicator signal based upon these dynamic signals. Consequently, consumable components, particularly of the brake arrangement, are only replaced when sufficiently worn to be unacceptable and not merely due to co-incidence with a regular vehicle service milestone.

Description

2351328 A Brake or Tyre Service Arrangement The present invention relates

to brake or tyre service for a motor vehicle and more particularly to a motor vehicle incorporating a range of sensors for vehicle control.

Increasingly vehicles are incorporating various control mechanisms in order to improve vehicle stability, traction and general performance. In order to provide these mechanisms typically a wide range of sensors are located within the vehicle to provide indication of current measurements of pressure, air temperature and speed, both vehicle and wheel etc. In such circumstances, a central controller for the vehicle receives a wide range of current indicators of vehicle performance dynamics.

With regard to a vehicle braking system traditionally brake pads and brake fluid etc., have been replaced at regular service intervals. Similarly, vehicle tyres can be replaced dependent upon extrapolated tyre wear predictions in order to judge whether tyres should be changed at a service interval even through currently acceptable. Clearly, servicing of a vehicle is a significant expense with regard to vehicle operation and so over recent years manufacturers have attempted to extend at least the mileage intervals between major services. Furthermore, better vehicle components have extended the practical operational life of the vehicle. However, with regard brake pads and fluids, similar extensions in reliable service life have not been made so there is a greater possibility of failure between vehicle service intervals. It will also be understood that different drivers will cause different rates of wear upon vehicle consumable components dependent upon their driving style and journey types.

In the above described circumstances, it will be appreciated that it is possible for acceptable brake pads or fluids to be replaced when not necessary and, jnore importantly, potentially unacceptable brake pads fluids to remain in use in a vehicle until the next service is performed.

Recently, in order to determine when brake pads or other brake system consumable must be replaced it has been known to incorporate specific and bespoke sensors indicating brake pad wear and temperature in order to provide an indication that servicing is required. Such bespoke sensors and therefore brake system service control mechanisms are relatively expensive. Thus, typically only top of the range vehicles will incorporate such a brake service indicator mechanism. Furthermore, it will be appreciated that normally are only attached to one pad on each axle to control costs thus, as brake pads do not wear evenly, there is a possibility of a distorted results.

Clearly, in addition to the advantages of fuller utilisation of consumable brake components, it will be understood that if these brake components are more fully utilised then there should be a reduced number of such components which require disposal with inherent environmental benefits.

It is an object of the present invention to provide a brake or tyre service arrangement which substantially meets the above mentioned objective of improved brake arrangement utilisation without significantly increasing costs.

In accordance with the present invention there is provided a brake or tyre service arrangement for a motor vehicle including vehicle dynamic sensor mechanisms, the arrangement comprising control means to be coupled to a vehicle dynamic sensor mechanism remote from the vehicle brake system in order to receive at least one dynamic signal and the control means consolidating that dynamic signal with known brake system or tyre specification parameters to provide a service indicator signal to indicate whether a brake or tyre service is necessary.

Typically, the dynamic sensor mechanism will be an accelerometer and/or a gyroscope sensor and/or temperature sensor and/or brake pressure sensor and/or engine speed sensor and/or wheel speed sensor for each respective wheel of a vehicle.

The control means may consolidate historically and/or instantaneously with regard to the dynamic signal received from the dynamic sensor mechanism.

The control means may provide a service indicator signal whereby brake or 10 tyre service may be predicted as necessary at a specified advanced stage, such as 500 miles, before a second service indicator signal is provided to indicate that a brake service is now necessary.

The service indicator signal may relate specifically to brake fluid or to brake pads possibly of each individual wheel of the vehicle.

The brake or tyre service arrangement may be interrogated when the vehicle is generally serviced in order to provide an advisory status of the vehicle brake arrangement.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawing in which a brake service 20 arrangement is pictorially illustrated.

In the drawing, a pictorial representation of a motor vehicle 10 is depicted. Within this motor vehicle 10 there is provided a brake arrangement incorporating a hydraulic or electronic control circuit to respective brake callipers 11 associated with each respective wheel 12. Clearly, the function of the brake arrangement through the callipers 11 is to slow or stop the vehicle 10 when required. However, the brake pads used in the callipers 11 and the hydraulic fluid (when used) wear and deteriorate over time. Thus, as indicated above these consumable components must be replaced as required. Previously, such replacement has taken place at regular service intervals irrespective of whether the components actually needed replacement. Such an approach is not efficient.

Similarly, with regard to a vehicle there are provided wheels which wear with use and so diminish in their effectiveness. Thus, these wheels must be replace when required but preferably only when required in order to maximise economic life and environmental impact of disposal. Previously, a regular visual inspection of the tyre, possible with a depth gauge, was used but this approach can be unreliable and dependent upon experience.

In accordance with the present invention a controller 1 associated with the vehicle 10 is arranged to receive dynamic sensor signals from sensors within the motor vehicle 10. These sensors will normally be utilised with regard to other functional features of the vehicle 10. Thus, for example, the vehicle 10 may include a traction control or airbag deployment mechanism utilising accelerometers within the vehicle 10. Furthermore, vehicle stability may be adjusted through longitudinal and lateral sensors located appropriately within the vehicle 10.

In the embodiment depicted in the drawing, the controller 1 receives dynamic signals from a pressure sensor 4 associated with the brake arrangement, wheel speed sensors 5 associated with each wheel 12, a yaw rate sensor 6 indicating yaw of the vehicle as it is driven, a lateral acceleration sensor 7 used to determine sideways motion of the vehicle 10 and a steering wheel angle sensor 8 to indicate steering wheel angle and therefore wheel 12 configuration as the vehicle is driven. Furthermore, there will normally be an accelerometer to determine fore and aft motion indicative of vehicle braking and a brake switch sensor to simply indicate when the brake system is operated.

Each of these sensors 4, 5, 6, 7, 8 are typically utilised within a socalled dynamic stability control (DSC) system within a vehicle 10, Clearly, each of the dynamic signals provided by the sensors 4 to 8 varies as the vehicle 10 is driven dependent upon the nature of the vehicle journey and the vehicle's 10 driver.

In accordance with the present invention, the controller 1 consolidates the various dynamic signals provided by the sensors 4 to 8 in order to provide an indicator signal to indicate whether the brake arrangement or tyre requires servicing.

Typically, the controller 1 will incorporate an appropriate relational algorithm to compare and consolidate the respective dynamic signals provide by the sensors 4 to 8. In such circumstances, the controller 1 may be tuned to the specific capabilities of the vehicle 10 in which it is incorporated. Furthermore, the controller 1 may be adjusted dependent upon the driver or the nature of expected vehicle 10 operation.

In essence, the whole purpose of the present invention in terms of a brake service arrangement is to ensure that the consumable components of the brake arrangement are more fully utilised prior to replacement in the vehicle 10 servicing programme. A similar approach is taken with regard to vehicle tyres.

Thus, it will be understood that the controller 1 could act upon an historical consolidation of the respective dynamic signals provided by the sensors 4 to 8 or act at specific time intervals in order review the current brake arrangement or tyre status and thereby provide an appropriate indicator signal determinant of the necessity for a brake arrangement service or tyre replacement. It will also be understood that both an historic and a time period based approach may be taken by the controller 1 in order to provide the best service indicator signal.

Typically, the indicator signal will be provided through an appropriate warning lamp within the vehicle 10. However, it will also be understood that the controller 1 may be specifically interrogated by the service engineer when the vehicle 10 is serviced in order to determine whether the consumable components of the brake arrangement should be replaced or provide a prediction as to when such components should be replaced subsequent to the vehicle service. Clearly, it thereby follows that respective indicator lamps could be provided within the vehicle 10 to provide an indication to a driver which predicts the necessity to replace consumable components of the brake arrangement or a tyre at a predetermined period before such replacement is necessary whereupon a second indicator lamp would be illuminated. Such a feature may be of particular benefit when it is know that servicing may not be possible for a particular time period or mileage i.e. on an expedition to a remote region with limited garaging facilities.

As indicated above, typically the service indicator signal provided by the controller dependent upon the dynamic signals received from the sensors 4 to 8 will activate an appropriate lamp or similar device within a vehicle 10. However, it will also be understood that respective indicator signals could be provided for specifically the brake fluid or brake pads within the vehicle 10 such that the service engineer could be more specifically directed towards those components of the brake arrangement which must be replaced. It will also be understood that individual brake pads within the vehicle 10 may be indicated by respective indicators operated by the service indicator signal from the controller 1.

As intimated above, the sensors 4 to 8 used by the present brake or tyre service arrangement will be those remote from the actual brake arrangement itself. Thus, the sensors 4 to 8 used within the present brake service arrangement will inherently have a dual function within the vehicle 10 in that they act with regard to the dynamic stability control mechanism as well as providing a service indicator signal as appropriate. In such circumstances, incorporation of the present arrangement within the vehicle 10 will be relatively cheap both in terms of additional components and installation.

The sensors 4 to 8 used by the present service arrangement can be grouped as those generally providing dynamic signals indicative of vehicle 10 operational performance. Thus, if the vehicle 10 is driven particularly aggressively these sensors 4 to 8 will provide a reciprocal indicative dynamic signal to the controller 1 in order that the controller 1 can thereby consolidate such signals into a service indicator signal consistent with that manner of vehicle 10 operation. Clearly, the manner of vehicle operation will vary with driver and so normally the controller 1 will be arranged to act historically based upon dynamic signals received over a period of time such that the accumulated effects upon the consumable components of the brake arrangement are thereby consolidated over time in order to provide a consolidated service indicator signal Tore consistent with long term vehicle 10 operation rather than short term vehicle 10 operation.

The sensors 4 to 8 used will typically include a gyroscope for indication of vehicle 10 cornering, an accelerometer for indication of vehicle 10 braking, pressure transducers for indicating severity of brake, wheel speed sensors to indicate general vehicle speed and temperature sensors to provide an indication of climatic effects upon the rate of consumable component wear.

In addition to utilising the dynamic signals in order to provide a service indicator signal for a brake arrangement it will be understood that the dynamic signals from the sensors could be used to indicate steering column bush wear, wheel bearing wear and transmission power train wear. However, generally such information will be determined from a specific interrogation of the controller 1 at servicing rather than through a specific indicator within the vehicle 10. It will be understood that wear to the steering column bush, wheel bearing and power or transmission train although determined by the nature of vehicle 10 operation will normally not be incorporated within the normal service routine for the vehicle 10.

In any event, these service indicator signals may provide the driver of the vehicle 10 with an indication of how their particular driving style is affecting the wear upon consumable components within the vehicle 10.

Generally, the present brake or tyre service arrangement win provide through the service indicator signal an indication of tyre and brake pad wear along with when brake fluid changes must occur. Clearly, in such circumstances it is necessary for the controller 1 to have some reference to the brake system specification in terms of the capabilities of the brake pad, tyres and brake fluid used within the vehicle 10. These brake system specification parameters will normally be supplied to the controller 1 by the service engineer upon servicing of the vehicle 10. Thus, if new brake pads have been added at the service this will be indicated to the controller 1 in order that the controller 1 can make appropriate adjustment in the consolidation of the dynamic signals from the sensors 4 to 8 when providing the service indicator signal subsequently. Alternatively, if partially worn brake pads, for whatever reason, are used with regard to the service of a vehicle 10, this could also be indicated to the controller 1 so that appropriate adjustment can be made in the consolidation of the dynamic signals in order to provide the service indicator signal described previously.

In addition to using the vehicle dynamic stability control mechanism as described previously, it will be understood that an operation switch 9 could be added to provide a simple numerical indication to the controller 1 of the number of times the brake pedal is operated. Furthermore, the controller could also receive dynamic signals from the vehicle suspension damper, rain sensors indicating the road surface upon which the vehicle 10 has been driven and a sensor indicative of the degree of pedal effort effected by the driver of the vehicle 10.

In order to improve vehicle maintenance it will be appreciated that the dynamic signals of the manner of operation of the vehicle 10 can be consolidated into a report which may be interrogated by the service engineer in order to allow future vehicle 10 operation and new vehicle designs to be altered for better performance. Furthermore, the controller 1 may provide an on-going or specifically interrogated report possibly through a satellite communication as to current vehicle 10 status. In some circumstances, the owner of the vehicle 10 may be contacted by the service engineer or dealer in order to have their vehicle serviced at an appropriate time.

Claims

- 10CLAIMS

A brake or tyre service arrangement for a motor vehicle including vehicle dynamic sensor mechanisms, the arrangement comprising control means to be coupled to a vehicle dynamic sensor mechanism remote from the vehicle brake mechanism in order to receive at least one dynamic signal and the control means consolidating that dynamic signal with known brake system specification parameters to provide a service indicator signal to indicate whether a vehicle service such as for the brake arrangement is required.
2. An arrangement as claimed in Claim I wherein the dynamics sensor mechanisms include an accelerometer and/or a temperature sensor and/or a brake pressure sensor and/or an engine speed sensor and/or a wheel speed sensor and/or gyroscope sensor.
3. An arrangement as claimed in Claim I or Claim 2 wherein the control means consolidates the dynamic signals historically over a period of time in order to provide the service indicator signal.
4. An arrangement as claimed in Claim 1 or Claim 2 wherein the control means consolidates the dynamic signal at specific time periods in order to provide the service indicator signal.
5. An arrangement as claimed in any preceding claim wherein the control means is arranged to provide the service indicator signal when necessary.
6. An arrangement as claimed in any preceding claim wherein the control means is arranged to provide the service indicator signal when it is precticted that a vehicle service will be required after a pre-determined time period of additional operation or mileage but is currently not essential.
7. An arrangement as claimed in any preceding claim wherein the service indicator signal is provided in respect of brake fluid condition.
8. An arrangement as claimed in any preceding claim wherein the service indicator signal is provided in respect of brake pad wear.
9. An arrangement as claimed in Claim 8 wherein the service indicator signal is provided in respect of each individual wheel of a motor vehicle.
10. An arrangement as claimed in any preceding claim wherein the control means may be interrogated in order to provide a report as to vehicle operation when that vehicle is serviced.
11. A brake service arrangement substantially as hereinbefore described with reference to the accompanying drawing.
12. A motor vehicle including a brake service arrangement as claimed in any preceding claim.