WO1999041521A1

WO1999041521A1 - Monitoring systems

Info

Publication number: WO1999041521A1
Application number: PCT/GB1999/000453
Authority: WO
Inventors: Alastair John Young; Roger Morrall
Original assignee: Automotive Products Plc
Priority date: 1998-02-13
Filing date: 1999-02-12
Publication date: 1999-08-19
Also published as: AU2534599A; GB9803050D0

Abstract

An in-vehicle drive-line vibration monitoring system which includes sensing means (20) associated with one or more drive-line components (7) to sense the vibration thereof and provide signals representative thereof. A control unit (21) receives the vibration signals from the sensing means (20) and processes these signals to provide output display signals indicative of the sensed vibration. A visual and/or auditory display unit (20) displays these signals to the vehicle operator. The control unit (20) may additionally or alternatively provide output signals for disengaging a clutch (4) in the drive-line or changing the operative ratio of a transmission or gearbox (3) in the drive-line if a predetermined vibration condition is attained.

Description

MONITORING SYSTEMS

This invention relates to monitoring systems for vehicle operating parameters.

Traditionally in a motor vehicle (such as an articulated lorry consisting of a tractor unit, which houses the driver and drive-line and a trailer which houses the vehicle load) the driver is able to directly detect when the vehicle drive-line is experiencing vibration levels likely to prove detrimental to the long term life of the drive-line.

However with the increasing improvements in such vehicles in terms of the isolation of the driver from the noise and vibrations experienced in the drive-line (e.g. mounting of the driver's cabs on springs and, better sound suppression etc.) problems can arise due to driver unwittingly operating the vehicle at high levels of vibration which results in premature wear of the drive-line components.

In an attempt to overcome this potential problem, drive-line components are made large and heavier in order to withstand the wear due to operation at or around the resonant frequencies of the drive-line. This significantly increases the cost and weight of such components making the vehicles less economical to produce and operate than would otherwise be necessary.

It is an object of the present invention to provide an arrangement which reduces the likelihood of a drive-line being operated in the above undesirable vibrating condition.

Thus according to the present invention there is provided a vehicle drive-line vibration monitoring system characterised by comprising sensing means associated with one or more drive-line components to sense the vibration thereof and provide signals representative thereof, a control unit which receives the vibration signals from the sensing means and processes said signals to provide output display signals indicative of the sensed vibration, and a visual and/or auditory display unit for receiving said display signals and displaying same to the vehicle operator.

The control unit preferably compares the signals from the sensing means with a signal or signals representative of a predetermined vibration condition and provides an output signal when the sensed signal attains a predetermined relationship to said predetermined vibration condition

The predetermined vibration condition signals may vary with predetermined drive-line or vehicle operating parameters.

The predetermined vibration condition signal may be stored as a three dimensional map of vibration amplitude against drive-line speed of rotation and against the throttle opening of an engine which drives the drive-line.

The sensing means may comprise a sensor associated with teeth or another marker (such as integral magnets, slots or other formations) on an input gear of an associated vehicle transmission or gearbox which move past the sensor as the drive-line rotates.

Alternatively, or additionally, where the drive-line includes a flywheel, the sensing means may comprise a sensor associated with peripheral teeth or another marker on the flywheel which move past the sensor as the drive-line rotates.

Typically, the sensing means associated with the teeth or said another marker may comprise a Hall Effect probe which senses, as a change in magnetic flux, the passage of the teeth or said another marker past the probe and hence any torsional vibrations in the drive-line. Alternatively an inductive coil or capacitive type of probe or a light beam type sensor could be used.

Where peripheral teeth on a flywheel are employed, these teeth may comprise existing teeth such as those engaged by an associated starter motor or teeth used as sensors for an engine management system or may be specially provided for this purpose. Where an engine management system is already provided it may be possible for the same sensing probe to provide both engine management and vibration signals.

The monitoring system may also sense the vibration of several components in the drive-line and compare these vibration signals to assess drive-line vibration.

The control unit may also be provided with a memory store and an outlet port from which data can be downloaded from the memory store onto a computer or other data analysis means to give a vibration record over a period of time (e.g. between vehicle services) to enable diagnosis of vibration problems.

The control unit may also be arranged to produce an output signal to disengage a clutch in the drive-line if a predetermined vibration condition is attained.

Alternatively the control unit may also be arranged to produce an output signal to initiate a ratio change in a gear box which forms part of the drive-line if a predetermined vibration condition is attained.

The invention also provides an in-vehicle vibration monitoring system having either the clutch disengagement or ratio changing function described above without the vibration display capability .

The invention also provides a vehicle drive-line provided with an in-vehicle vibration monitoring system of any of the forms described above.

The invention further provides a vehicle drive-line which includes a twin-mass flywheel and which is characterised by the inclusion of a drive-line vibration monitoring system comprising sensing means associated with an input and/or output mass of the flywheel to sense the vibration thereof and provide signals representative thereof, a control unit which receives the vibration signals from the sensing means and processes said signals to provide output display signals, and a visual and/or auditory display unit for receiving said display signals and displaying same to the vehicle operator.

One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying figure 1 which shows diagrammatically part of an articulated lorry which includes a drive-line vibration monitoring system in accordance with the present invention.

Referring to figure 1, a lorry engine 1 having a crankshaft 2 drives a transmission 3 via a clutch 4 and a flywheel 5. The transmission has an input shaft 6 on which is mounted an input gear 7 and an output shaft 8 which is connected with drive wheels (not shown) .

The flywheel 5 may be a twin mass flywheel as shown or a conventional one piece solid flywheel. In the example shown, the twin mass flywheel comprises an input flywheel mass 11 and an output flywheel mass 12 which are interconnected by a damping means 13 which may comprise springs and/or linkages etc. as described, for example, in the Applicant's earlier patents Nos. GB 2229793 and 2282868 and Applications Nos. PCT/GB95/01976 and PCT/GB97/00361. Alternatively any other type of twin mass flywheel arrangement may be used and, as indicated above, the present invention still has applicability when a solid flywheel is employed.

The engine 1 and transmission 8 are mounted on a chassis shown diagrammatically at 14. Suspended from the chassis via vibration mounts 15 is a drivers cab 16.

In accordance with the present invention, the transmission 3 is provided with a vibration sensing means in the form of a sensing probe 20 mounted adjacent input gear 7. The probe 20 is connected via line 20' with an electronic control unit 21 mounted in the cab 16 which in turn is connected with a dashboard mounted display unit 22.

The sensing probe 20 may take any suitable form. For example, a Hall Effect probe may be used which senses changes in a magnetic flux as the teeth of input gear 7 pass the probe thus enabling torsional vibrations in the rotation of input gear 7 to be sensed. Alternatively, for example, an induction coil type probe could be used to provide a voltage output which varies with the passage of the teeth of gear 7 past the probe.

The signals from sensing probe 20 are passed to electronic control unit 21 which processes the signals to provide output display signals to display unit 22. The display unit 22 has a visual display 23 and an integral speaker 24 on which audible warnings can be sounded to the vehicle driver.

The visual display 23 of display unit 22 may display to the driver a continuous read-out of vibration amplitude from sensor 20 and/or warning messages when particular pre-determined and potentially harmful torsional vibration conditions are being experienced by the input gear 7. These potentially dangerous conditions may be reinforced by an audible system of warning tones from speaker 24 whose volume and/or frequency of oscillation vary as the severity of the drive-line vibration varies.

The processing of signals in control unit 21 may take a variety of other forms depending on the type of display which is to be implemented on display unit 22.

For example, the signals from sensor 20 may be compared with a signal or signals indicative of a predetermined vibration condition or conditions (e.g. a threshold level indicative of the onset of an undesirable level(s) of vibration) and the output display signals thus provided are then representative of the relationship between the sensed signals and the predetermined vibration condition or conditions. In such an arrangement, for example, the display unit may only provide an output, or may dramatically change its display, when a predetermined level of vibration is sensed.

The predetermined vibration condition or conditions with which the sensed signals are compared may be varied in response to the variation of predetermined drive-line or vehicle operating parameters. For example, the predetermined vibration condition signals may be stored as a three dimensional map of vibration amplitude plotted against the speed of rotation of the drive-line and against the throttle opening of engine 1. Numerous other forms of visual display are possible. For example, a system of coloured warning lights 25 may be built into the display unit 22 in addition to or in place of the visual display 23. These warning lights may be, for example, green when an acceptable vibration condition exists and progress through orange to red as the vibration condition worsens. Additionally, or alternatively, the frequency of flashing of the lights can also be arranged to vary to impress upon the driver the increasing urgency of the drive-line vibration situation.

Control unit 21 is provided with an output socket 26 to which a computer may be connected, for example during servicing of the vehicle, in order to download from a memory store within unit 21 a vibration record of the operation of the transmission since the last service or since resetting of the memory of the control unit. Such a download capability provides a useful check for the maintenance management of the vehicle and can detect, for example, if the driver is in the habit of ignoring the warnings from display unit 22 and continuing to drive in potentially dangerous vibration conditions for extended periods of time.

The input mass 11 of the twin mass flywheel 5 is provided with peripheral teeth 30 which are engaged by an associated engine starter motor (not shown). If desired, these teeth may be used in combination with a sensor similar to sensing probe 20 as the vibration sensing means of the monitoring system in accordance with the present invention in place of the input gear sensing probe.

Many current vehicles employ an engine management system which controls the ignition, timing and fuel injection etc. of the engine. Such engine management systems conventionally employ teeth similar to teeth 30 and an associated probe similar to probe 20 referred to above as the engine speed and timing sensors and the signals from such a system may also be used to provide the vibration sensing signal required by the present invention in place of the additional transmission sensor 20 described above. The vibration sensing means may alternatively, or even additionally, be associated with the output flywheel mass 12.

As a further alternative a toothed disc driven from an auxiliary drive shaft which emerges as the other end of the engine from the flywheel could be used as the source of the vibration signals.

Also, as an alternative to using teeth on a gear wheel, flywheel or disc, other forms of marker such as integral magnets, slots or other formations on the gear wheel, flywheel or disc which rotate past the sensing probe may be used.

In the various alternative arrangements described above the vibration monitoring system provides an output signal whose sole purpose is to advise the vehicle driver of the onset of undesirable levels of vibration in the vehicle drive-line. The system could alternatively be setup so that control unit 21 provides an output signal which is directed via line 31 to a clutch actuator 30 (which may, for example, be hydraulically and/or electrically operated) which when activated operates on clutch clamp spring 4' to disengage clutch 4 to prevent or minimise damage to the drive line. The clutch actuator 30 may be the actuator used for normal operation of the clutch or may be an additional actuator.

This clutch disengagement capability is preferably additional to the vibration display/warning capability but could be in place of such display/warning capability. Also, the vibration level at which the clutch is disengaged could conveniently be set at a higher level than that at which the system starts to warn the driver that the drive-line vibrations are potentially damaging

In a further alternative arrangement the control unit 21 could provide an output signal which is directed via line 32 to a transmission ratio selection unit 33 (which may, for example, be hydraulically and/or electrically operated) which when activated initiates a change in the operative ratio of the transmission 3 to reduce the sensed level of drive-line vibration. The transmission selection unit could be the normal control unit for an automatic transmission or, for example, an arrangement of hydraulic rams or electric motor arranged to act on the selector system of a manual transmission. Again, this ratio changing capability could be additional to or in place of the warning/display capability of the system and is preferably initiated at a higher level of vibration from the warning display. The present invention thus provides a useful aid to the vehicle driver to enable him to avoid driving the vehicle for extended periods of time in potentially damaging vibration conditions. As indicated previously, this is particularly important when the vehicle driver is housed in a vibration isolated cab in which he is unable to directly feel or hear the vibration conditions currently existing in the vehicle drive-line.

Claims

1. An in-vehicle drive-line vibration monitoring system characterised by comprising sensing means associated with one or more drive-line components to sense the vibration thereof and provide signals representative thereof, a control unit which receives the vibration signals from the sensing means and processes said signals to provide output display signals indicative of the sensed vibration, and a visual and/or auditory display unit for displaying said signals to the vehicle operator.

2. A monitoring system according to claim 1 characterised in that the control unit compares the signals from the sensing means with a signal or signals representative of a predetermined vibration condition and provides an output display signal representative of the relationship between the sensed signals and said predetermined vibration condition.

3. A monitoring system according to claim 1 or 2 characterised in that the predetermined vibration condition signals vary in response to the vibration of predetermined drive- line or vehicle operating parameters.

4. A monitoring system according to claim 3 characterised in that the predetermined vibration condition signals are stored as a three dimensional map of vibration amplitude against drive-line speed of rotation and against the throttle opening of an engine which drives the drive-line.

5. A monitoring system according to any one of claims 1 to 4 characterised in that the sensing means comprises a sensor associated with teeth or another marker on an input gear of an associated vehicle transmission or gearbox which move past the sensor as the drive-line rotates.

6. A monitoring system according to any one of claims 1 to 4 where the drive-line includes a flywheel characterised in that the sensing means comprises a sensor 10

associated with peripheral teeth or another marker on the flywheel which moves past the sensor as the drive-line rotates.

7. A monitoring system according to claim 5 or 6 characterised in that the sensing means associated with the teeth or said another marker comprises a Hall Effect probe which senses, as a change in magnetic flux, the passage of the teeth or said another marker past the probe and hence any torsional vibrations in the drive-line.

8. A monitoring system according to claim 5 or 6 characterised in that the sensing means associated with the teeth or said another marker comprises an inductive coil or capacitive type of probe or a light beam type sensor which senses the passage of the teeth or said another marker past the probe and hence any torsional vibrations in the drive-line.

9. A monitoring system according to claim 6 or claims 7 or 8 when dependent on claim 6 characterised in that the peripheral teeth on the flywheel are also engaged by an associated starter motor or are used by an associated engine management system.

10. A monitoring system according to any one of claims 1 to 9 characterised in that the system senses the vibration of several components in the drive-line and compares these vibration signals to assess drive-line vibration.

11. A monitoring system according to any one of claims 1 to 10 characterised in that the control unit is provided with a memory store and an outlet port from which data can be downloaded from the memory store onto a computer or other data analysis means to give a vibration record over a period of time.

12. A monitoring system according to any one of claims 1 to 11 characterised in that the display unit comprises an auditory display device which issues warning tones whose volume and/or frequency of oscillation varies with the severity of the sensed drive-line vibration. 11

13. A monitoring system according to any one of claims 1 to 12 characterised in that the display unit comprises a visual display device whose display colour and/or frequency of illumination varies with the severity of the sensed drive-line vibration.

14. A monitoring system according to any one of claims 1 to 13 characterised in that the control unit is also arranged to produce an output signal to disengage a clutch in the drive-line if a predetermined vibration condition is attained.

15. A monitoring system according to any one of claims 1 to 13 characterised in that the control unit is also arranged to produce an output signal to initiate a ratio change in a transmission or gear box which forms part of the drive-line if a predetermined vibration condition is attained.

16. A monitoring system according to claim 14 or 15 characterised in that clutch disengagement or ratio changing is initiated at a higher level of vibration from that at which the display unit begins to indicate a potentially damaging level of vibration.

17. An in-vehicle vibration monitoring system for a drive-line which includes a disengageable drive clutch, the system being characterised by comprising sensing means associated with one or more drive-line components to sense the vibration thereof and provide signals representative thereof, a control unit which receives the vibration signals from the sensing means and processes said signals to provide output signals to disengage the clutch if a predetermined vibration condition is attained.

18. An in-vehicle vibration monitoring system for a drive-line which includes a multi-ratio trasnmission or gearbox, the system being characterised by comprising sensing means associated with one or more drive-line components to sense the vibration thereof and provide signals representative thereof, a control unit which receives the vibration signals from the sensing means and processes said signals to provide output to initiate a ratio change in the transmission or gearbox if a predetermined vibration condition is 12

attained.

19. A vehicle drive-line characterised in that it is provided -with an in-vehicle vibration monitoring system according to any one of claims 1 to 18.

20. A vehicle drive-line which includes a twin-mass flywheel and which is characterised by the inclusion of a drive-line vibration monitoring system comprising sensing means associated with an input and/or output mass of the flywheel to sense the vibration thereof and provide signals representative thereof, a control unit which receives the vibration signals from the sensing means and processes said signals to provide output display signals, and a visual and/or auditory display unit for receiving said display signals and displaying same to the vehicle operator.

21. An in-vehicle drive-line vibration monitoring system constructed and arranged substantially as hereinbefore described with reference to and as shown in the accompanying drawing.