WO2017194957A1

WO2017194957A1 - Control systems and methods

Info

Publication number: WO2017194957A1
Application number: PCT/GB2017/051328
Authority: WO
Inventors: Jonathan Wilson; Daniel HYDEN
Original assignee: Alexander Dennis Limited
Priority date: 2016-05-12
Filing date: 2017-05-12
Publication date: 2017-11-16
Also published as: GB201820260D0; GB201608308D0; GB2567564B; GB2567564A

Abstract

There is described a control system for a passenger service vehicle, comprising at least one tyre-condition system in communication with a sensor arrangement and configured to determine a condition of a tyre of the vehicle. The control system may comprise a vehicle controller, in communication with the tyre-condition system, and may be configured to control speed characteristics of the vehicle based upon the determined tyre condition. In some examples, the vehicle controller may be configured to limit the speed of the vehicle based on the determined tyre condition. In further examples there is described a passenger service vehicle wherein at least the rear axle comprises only two tyres. The passenger service vehicle may use the control system to determine a condition of those tyres, in the manner above.

Description

Control Systems and Methods

Technical Field

Described examples relate to the field of control systems and methods, particular for passenger service vehicles, and the like.

Background

As used herein, the term "passenger service vehicle" encompasses vehicles for transporting passengers and, in particular, road vehicles for transporting passengers. Exemplary passenger service vehicles may be buses (single or double deck), coaches or the like.

Significant innovation and technology development has occurred in recent years in relation to passenger service vehicles. In particular, there has been a continued drive towards providing vehicles that have low running costs, and improved fuel efficiency, etc., while at the same time maintaining or improving the safety of those vehicles.

This background serves only to set a scene to allow a skilled reader to better appreciate the following description. Therefore, none of the above discussion should necessarily be taken as an acknowledgement that that discussion is part of the state of the art or is common general knowledge. One or more aspects/embodiments of the invention may or may not address one or more of the background issues. Summary

In some examples, there are described control systems and methods for vehicles, such as passenger service vehicles. The described systems and methods may help improve fuel efficiency, and in some cases reduce running costs, maintenance costs, and vehicle downtime. The described systems and methods may help improve or maintain the safe operation of such vehicles.

In one example, there is described a control system comprising at least one tyre- condition system. The tyre-condition system may comprise and/or be in communication with a sensor arrangement to allow for monitoring of the condition of a tyre of the vehicle. The tyre-condition system may be configured to determine a condition of a tyre of the vehicle (e.g. from data received/collected from the sensor arrangement). The control system may further comprise a vehicle controller in communication with the at least one tyre-condition system. The vehicle controller may be configured to control the speed of the vehicle based on the determined tyre condition. For example, the vehicle controller may be configured to limit the maximum speed, and/or limit the rate of acceleration, based on a particular determined tyre condition.

The tyre-condition system may be configured to determine from the sensor arrangement, during the travel of a vehicle, a travelling load at an axle of the vehicle, for example, at one or more axles, or indeed one or more wheels/tyres. The vehicle controller may be configured to limit maximum speed, and/or limit the rate of acceleration when a particular threshold associated with the tyre condition has been met (e.g. exceeded). The threshold may relate to the load being experienced at the tyre. The threshold may additionally relate to the present tyres being used on the vehicle (e.g. the load rating of those tyres).

The tyre-condition system may be configured to determine a tyre condition of the vehicle directly from a sensor arrangement, for example, by measuring forces, or the like, at one or more tyres/axles. Alternatively, the tyre-condition system may be configured to determine a tyre condition indirectly, for example, by obtaining data (e.g. pressure data) from a sensor arrangement within a vehicle subsystem, such as a suspension system, or the like. In which case, the tyre-condition system may be configured to calculate the tyre condition from the measured pressure data, or the like.

In some examples, the control system - and in particular the tyre-condition system - may comprise a correction device. The correction device may be configured to allow the control system to calculate an approximate static load at a tyre of the vehicle based on a determined tyre condition (e.g. travelling load at the tyre). In other similar words, the correction device may allow for an approximation of the load that the vehicle would otherwise experience at the axle/tyres, were that vehicle to be stationary. That approximation may be based on the sensed tyre condition. In those cases, the vehicle controller may be configured to control speed characteristics (e.g. speed and/or acceleration) of the vehicle using a calculated approximate static load at the tyre (e.g. rather than a tyre condition, directly).

The correction device may be configured to allow the control system to calculate an approximate static load using a correction characteristic. Such a characteristic may provide a correction factor. The correction factor may be associated with any modification to the load that is being experienced at the tyre due to present driving conditions, compared to the load when the vehicle would otherwise by stationary. The correction factor may be based on the aerodynamics of the vehicle. The correction factor may be based on driving conditions, such as acceleration/deceleration, vehicle gradient, or the like. The correction factor may be a function of vehicle speed. The correction factor may also be based on static load, or subsequently calculated approximate static load.

The correction device may use a present speed of the vehicle together with the initial static load, and/or a subsequently calculated approximate static load, in order to determine the correction factor.

In some examples, the vehicle controller may be configured to set one or more speed characteristics (e.g. maximum speed) of a vehicle in the event of a particular vehicle usage, such as determined tyre condition (e.g. travelling load), or indeed calculated approximate static load. In those cases, the vehicle controller may be configured to unset subsequently the one or more speed characteristics in the absence of the determined vehicle usage. However, in some examples, the vehicle controller may be configured to unset (e.g. only unset) when a determined driving condition has been observed by the vehicle controller.

The driving condition may include a reduction in speed by a particular threshold amount. For example, the vehicle controller may be configured to unset one or more speed characteristics (e.g. maximum speed limit) but only when the speed of the vehicle has been reduced by a particular threshold amount, such as 5 kph, 10 kph, 20 kph, or the like. The tyre-condition system may be configured to determine tyre pressure. The vehicle controller may be configured to control speed characteristics of the vehicle based on the pressure from the determined tyre condition. For example, when the controller determines that one or more tyres are below a particular threshold, then the vehicle controller may be configured to set a particular speed limit, which may be a second - and sometimes lower - speed limit (e.g. when the controller has already set an initial speed limit based on load at the tyres).

In some examples, the control system may comprise a first tyre-condition system configured to determine, as a tyre condition, a travelling load at the tyres, and a second tyre-condition system configured to determine, as a tyre condition, the pressure of the tyres. In such examples, the vehicle controller may be configured to control speed characteristics based on one or both of the tyre conditions determined from first and second tyre-condition systems.

In some examples, the control system may be specifically configured for use with double-deck passenger service vehicles. The control system may be for use with double-deck-vehicles using single tyres on some or all axles. The control system may be for use with double-deck-vehicles using single tyres on some or all axles, which would not otherwise be rated for the vehicle.

The control system may be retrofitable to vehicles. In such cases, the control system may use vehicle data being communicated on CAN buses or the like. In some examples, there is described a control system for a passenger service vehicle, comprising: at least one tyre-condition system in communication with a sensor arrangement and configured to determine a tyre condition from data received from the sensor arrangement, during travel of the vehicle;

a vehicle controller, in communication with the at least one tyre-condition system, and being configured to control speed characteristics of the vehicle based upon the determined tyre condition.

In some examples, the tyre-condition system may be configured to determine, as a tyre condition, a travelling load of the tyre. In some examples, the tyre-condition system may be configured to determine, as a tyre condition, the pressure of the tyre.

In some examples, there is described a control system for a vehicle, such as a passenger service vehicle, comprising:

at least one tyre-condition system in communication with a sensor arrangement, and configured to determine from data received from the sensor arrangement, during travel of the vehicle, a travelling load at tyre of the vehicle; and the tyre-condition system further comprising a correction device configured to allow the control system to calculate an approximate static load at the tyre based on a determined travelling load at the tyre.

The control system may be in communication with a user interface in order present, for example, a calculated approximate static load to a user (e.g. driver).

The control system may comprise a vehicle controller, in communication with the tyre- condition system. The vehicle controller may be configured to control speed characteristics of the vehicle based on the calculated approximate static load. In further examples, there is described a control system for a vehicle, such as a passenger service vehicle, comprising:

a vehicle controller configured to set one or more speed characteristics of a vehicle in the event of particular determined vehicle usage (e.g. determined and/or calculated load at the axles), and wherein the vehicle controller is configured to unset subsequently the one or more speed characteristics in the absence of the determined vehicle usage, only when a determined driving condition has been observed by the vehicle controller. The driving condition may include a reduction in speed by a particular threshold amount. For example, the vehicle controller may be configured to unset one or more speed characteristics (e.g. maximum speed limit) but only when the speed of the vehicle has been reduced by a particular threshold amount, such as 5 kph, 10 kph, 20 kph, or the like.

In some examples, there is described a method for controlling a vehicle, such as a passenger service vehicle.

The method may comprise determining, during travel of the vehicle, a tyre condition of the vehicle. The method may comprise controlling speed characteristics of the vehicle based upon the determined tyre condition.

The method may comprise determining, as a tyre condition, a travelling load of the vehicle. Such a travelling load may be determined directly, for example, by measuring forces, or the like, associated with one or more tyres. Alternatively, the method may comprise determining a travelling load indirectly, for example, by measuring pressures within a vehicle subsystem, such as the suspension system, or the like. In which case, the method may comprise determining the travelling load from the measured pressures.

The method may comprise controlling the speed of the vehicle based on the determined tyre condition. The method may comprise limiting the speed (e.g. maximum speed), and/or limiting the rate of acceleration (e.g. maximum rate of acceleration), based on a particular determined tyre condition (e.g. travelling load). The method may comprise limiting the speed, and/or limiting the rate of acceleration when a particular threshold has been met (e.g. exceeded). The threshold may relate to the load at the tyre. The threshold may additionally relate to the present tyres being used on the vehicle (e.g. the load rating of those tyres).

The method may comprise calculating an approximate static load at the tyre of the vehicle based on a determined tyre condition (e.g. travelling load at the axle). In other similar words, the method may comprise calculating for an approximation of the load that the vehicle would otherwise experience at the axle/wheels, were that vehicle to be stationary, and that approximation may be based on the sensed tyre condition.

The method may comprise controlling speed characteristics (e.g. speed and/or acceleration) of the vehicle using a calculated approximate static load at the tyre (e.g. rather than a travelling load, directly).

The method may comprise calculating an approximate static load using a correction factor. Such a correction factor may be associated with any modification to the load that is being experienced at the tyre due to present driving conditions, compared to the load when the vehicle would otherwise by stationary. The correction factor may be based on the aerodynamics of the vehicle. The correction factor may be based on driving conditions, such as acceleration/deceleration, vehicle gradient, or the like. The correction factor may be a function of vehicle speed. The correction factor may also be based on static load, or subsequently calculated approximate static load. The method may comprise using a present speed of the vehicle together with the initial static load, and/or a subsequently calculated approximate static load, in order to determine the correction factor.

The method may comprise setting one or more speed characteristics (e.g. maximum speed) of a vehicle in the event of a particular vehicle usage, such as determined tyre condition, or indeed calculated approximate static load. In those cases, the method may comprise unset subsequently the one or more speed characteristics in the absence of the determined vehicle usage. However, in some examples, the method may comprise un-setting when a determined driving condition has been observed.

The driving condition may include a reduction in speed by a particular threshold amount. For example, the method may comprise un-setting one or more speed characteristics (e.g. maximum speed limit) but only when the speed of the vehicle has been reduced by a particular threshold amount, such as 5 kph, 10 kph, 20 kph, or the like.

The method may comprise using a tyre pressure as a tyre condition in order to control speed characteristics of the vehicle. For example, the method may comprise determining that one or more tyres are below a particular threshold, then setting a second (e.g. lower) speed limit. In some examples, there is described a method for controlling a vehicle, such as a passenger service vehicle, comprising:

determining, during travel of the vehicle, a tyre condition of the vehicle; and controlling speed characteristics of the vehicle based upon the determined tyre condition.

The tyre condition may comprise the load being experienced at the tyre. The tyre condition may comprise the pressure of the tyre.

In some examples, there is described a method for controlling a vehicle, such as a passenger service vehicle, comprising:

determining, during travel of the vehicle, a travelling load at an axle of the vehicle; and

calculating an approximate static load at the axle based on the determined travelling load at the axle.

The method may comprise presenting, or otherwise communicating, to a user (e.g. a driver) a calculated approximate static load.

In further examples, there is described a method for controlling a vehicle, such as a passenger service vehicle, comprising:

setting one or more speed characteristics of a vehicle in the event of particular determined vehicle usage (e.g. determined and/or calculated load at the tyres) and un-setting subsequently the one or more speed characteristics in the absence of the determined vehicle usage, when a determined driving condition has been observed. The driving condition may include a reduction in speed by a particular threshold amount. For example, the method may unset one or more speed characteristics (e.g. maximum speed limit) but only when the speed of the vehicle has been reduced by a particular threshold amount, such as 5 kph, 10 kph, 20 kph, or the like.

The control system and methods described above may be useful with single deck or double-deck vehicles. In some examples, such vehicles may comprise two axles (or indeed three axles). Each axle may comprise two tyres for contact with the road. In some examples, one, two or three axles may comprise two tyres (e.g. two tyres only) for contact with the road, which have a tyre width of greater than 350 mm, such as around, or greater than, 380 mm. In some examples, the tyre width may be greater than 400 mm, or indeed roughly between 400 mm and 500 mm. In some cases, the tyres fitted to at least one of the axles may be considered to be super-single tyres. In some examples, at least the rear axle (or rear axles) may comprise super-single tyres (e.g. comprise only two rear super-single tyres). In some examples, such tyres may have a rim diameter of around 19.5 inches to 22.5 inches, or the like.

The control system and methods described above may be useful particularly with double-deck vehicles, but may be used on single deck vehicle (including coaches). In any event, such vehicles may have at least one axle (e.g. the rear axle) specifically configured to accommodate tyres having a width greater than 350 mm, such as around, or greater than, 380 mm (e.g. greater than 400 mm, or indeed roughly between 400 and 500 mm, or even greater). The axle may comprise an alterative rim arrangement, from a standard vehicle. The axle may comprise one or more spacers.

In some examples, there is described a passenger service vehicle comprising, at one axle, only two tyres for contact with the road, wherein each tyre has a width greater than 350 mm (e.g. around 380 mm, or greater, such as greater than 400 mm). The axle may be the rear axle. The tyres may be considered to be super-single tyres. The vehicle may comprise any of the features of the control system mentioned above. The methods may comprise operating any of the above features, as described. The methods may comprise optimising performance of a vehicle so as to reduce fuel usage, for example, using a particular set of tyres (e.g. super-single tyres). The method may comprise optimising performance of a vehicle so as to improve safety of the vehicle, for example, at various load conditions.

In some examples, there is described a computer program product that when programmed into a suitable controller configures the controller to perform any methods disclosed herein. There may be provided a carrier medium, such as a physical or tangible and/or non-transient carrier medium, comprising the computer program product. The carrier medium may be a computer readable carrier medium.

The invention includes one or more corresponding aspects, embodiments or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. As will be appreciated, features associated with particular recited embodiments relating to control systems, or the like, may be equally appropriate as features of embodiments relating specifically to methods of operation or use, and vice versa.

It will be appreciated that one or more embodiments/aspects may be useful in improving fuel efficiency, and in some cases reduce running costs, maintenance costs, vehicle downtime, and may help improve or maintain the safe operation of such vehicles. The above summary is intended to be merely exemplary and non-limiting. Brief Description of the Figures

A description is now given, by way of example only, with reference to the accompanying drawings, in which :-

Figure 1 show an example of a passenger service vehicle;

Figure 2 shows a simplified example of a drive train of the vehicle of Figure 1 ;

Figures 3a and 3b show examples of control systems for use with the vehicle of Figure 1 ;

Figure 4 shows an exemplary correction characteristic for use with the control system of Figure 3b; and

Figure 5 shows an example of a vehicle controller for use with the vehicle of Figure 1 .

Description of Specific Embodiments

Figure 1 shows a perspective representation of a passenger service vehicle 100, which, in this example, is shown as a vehicle 100 having both a lower passenger deck 110 (lower deck) and an upper passenger deck 120 (upper deck). Such vehicles 100 are commonly referred to as twin-deck, or double-deck, vehicles 100, and comprise a plurality of passenger seats on each deck. They may also comprise two or three axles, or the like. In this case, a twin-axle vehicle 100 having front and rear axles 105, 107 is shown. While some of the described examples below may be particularly useful for such double-deck vehciles, nevertheless it will be appreciated that features described below may equally be used together with single-deck passanger service vehicles.

Figure 2 shows a simplified plan-view representation of a drive train 130 of the vehicle 100 of Figure 1 , in which both front and rear axles 105, 107 are represented. Due to expected load conditions, and for safety, the rear axle 107 of the vehicle may comprise twin tyres 107a, 107b on each side of the axle 107.

In many cases, there may be a desire to improve the fuel efficiency of such vehicles 100, and in some cases reduce running costs, maintenance costs, and vehicle downtime. However, due to the operation of such vehicles (e.g. varying passenger loads), there may also be a desire to improve or maintain the safe operation of such vehicles.

Consider now Figure 3a, which shows a control system 200 that may be used with the vehicle 100 of Figure 1 . It will be appreciated from the following description that features of the control system 200 may be implemented as multiple discrete components, or indeed some or all components may be provided in hardware and implemented in software, firmware, or the like. Aspects of the control system 200 may be implemented on FPGAs, ASICs, or the like. Some components may be virtual components. Here, the control system 200 comprises a tyre-condition system 210. Here, the tyre- condition system 210 is in communication with a sensor arrangement 220, and arranged to receive data therefrom. The sensor arrangement 220 in this example is configured to measure parameters of a vehicle 100 subsystem relating to the wheels/axles 105, 107. In this case, the sensor arrangement 220 is configured to monitor the air pressure within the suspension system of the vehicle 100, and in particular the suspension system associated with the rear axle 107/tyres 107a. In other examples, the sensor arrangement 220 may be configured to measure forces/loads directly. However, by measured pressures, or the like, in the subsystem, then existing sensor arrangements 220 and data may be used within the control system 200. In such a way, the control system 200 may be more appropriately fitted to existing vehicles 100. It should also be mentioned that "in communication" with the sensor arrangement may include indirectly "in communication", e.g. when data is received from an intermediate controller, or the like.

In any event, data received from the sensor arrangement 220 can be used by the tyre- condition system 210 to determine, during the travel of a vehicle 100, tyre condition associated with one or more tyres, as will be further explained. It will be appreciated that the tyre condition may be determined for a single tyre, and/or for multiple tyres (e.g. multiple tyres 107a, 107b of an axle 107).

In this particular example, the tyre-condition system 210 is configured to determine a travelling load at the tyres of the vehicle 100. Such a travelling load may be considered to be the load that is being experienced by the vehicle 100 (e.g. at the tyres/axles) during transit of the vehicle 100. The tyre-condition system 210 may comprise a processor μΡ, and memory, or the like to calculate the tyre loads accordingly. It will be appreciated that such travelling loads on the vehicle 100, and indeed the tyres/axles, may be considered to be dynamic (e.g. live) and may differ from the static loads at the vehicle 100. In other words, the travelling load may be considered to be the load experienced due to present driving conditions, compared to the load when the vehicle 100 would otherwise by stationary. It will be appreciated that under certain conditions, the travelling load will be greater than the static load. Here, in Figure 3a, the control system 200 also comprises a vehicle controller 230, in communication with the tyre-condition system 210. The vehicle controller 230 here is configured to control speed characteristics of the vehicle 100 based upon the determined tyre condition, and in this case travelling load. For the purposes of the following examples, the vehicle controller 230 is described as being specifically configured to limit the maximum speed of the vehicle based on the determined driving conditions, such as travelling load. However, further or alternative speed characteristics may be controlled in different examples, such as rate of acceleration, or the like.

In the example shown, the vehicle controller 230 is in communication with the tyre- condition system 210 via an optional filter arrangement 240. Such a filter arrangement 240 may be considered to be a low pass filter. Rapid fluctuations in calculated load may be filtered at the filter arrangement 240.

In use, and as the vehicle 100 is travelling, the load at the axles/tyres may be determined. It will be appreciated that, during use, the tyres used at the vehicle 100 may be rated for particular driving conditions. There may, in some cases, be a maximum rated loading that would be safely permitted by certain tyres fitted to the axle 107. In those cases, the control system 200 and vehicle controller 230 may be configured to limit maximum speed, or otherwise control the speed of the vehicle 100, when a particular load threshold has been met (e.g. exceeded). It will be appreciated that the load of passenger service vehicles 100 may vary considerably during use, depending on passenger numbers, luggage, fuel reserve, etc. As such, fitting a vehicle with tyres that accommodate the maximum possible load usage may not be an efficient use of such tyres for much of the vehicle 100 usage. By having control over the vehicle speed, depending on load, it will be appreciated that tyre selection may be permitted such that smaller, or fewer, tyres may be fitted at the axles of the vehicle 100, which may be more suitable for much of the vehicle 100 usage (e.g. tyres, such as super-single tyres, having a tyre width of greater than 350 mm, such as between roughly 400 mm and 500 mm). In doing so, and by reducing road contact, inertial effects, etc. associated with bigger/more tyres, fuel efficiency can be improved while the safety of the vehicle 100 can be maintained or even improved. For example, single tyres may be fitted to the axles 107 of vehicles 100 that would otherwise previously have required double-tyre arrangements 107a, 107b. Such single tyres may have a tyre width of greater than 350 mm, such as around, or greater than, 380 mm. In some examples, the tyre width may be greater than 400 mm, or indeed roughly between 400 mm and 500 mm. In some cases, the tyres fitted to the one or both axles may be considered to be super-single tyres. In some examples, at least the rear axle may comprise super-single tyres (e.g. comprise only two rear super-single tyres for road contact).

While the above control system 200 may be effective in monitoring loads, and controlling vehicle characteristics - such as speed - accordingly, nevertheless in some circumstances vehicle safety ratings, such as tyre safety ratings, may be given on the basis of static loads, i.e. the acceptable load of a vehicle 100 when stationary. Due to the nature of a passenger service vehicle 100, and the varying loads, e.g. varying passenger numbers and/or fuel during use, it may be helpful to control more accurately the vehicle 100 speed characteristics based on static loads, or an approximation thereof.

Consider now Figure 3b, which shows a further example of the control system 200. Here, the control system 200, and in particular the tyre-condition system 210, further comprises a correction device 250, as will be explained. In particular, the correction device 250 is configured to allow the control system 200 to calculate an approximate static load at the tyres of the vehicle 100 based on a determined travelling load at the tyres (e.g. at the axle using the suspension system monitor). In other similar words, the correction device 250 may allow for an approximation of the load that the vehicle 100 would otherwise experience at the axle/tyres, were that vehicle 100 to be stationary.

Here, the correction device 250 calculates a correction factor for use with the determined travelling load. The correction factor can be considered to be used to modify the calculation of travelling load that is being experienced at the tyre(s) due to present driving conditions, compared to the load when the vehicle would otherwise by stationary. In the example shown, the correction device 250 is further in communication with a vehicle speed sensor arrangement 260, as will be explained. Figure 4 shows an exemplary correction characteristic 300 that may be used for a particular vehicle 100, and from which a correction factor K may be obtained. Here, the x-axis represents the load of the vehicle when initially stationary (e.g. static load) while the y-axis represents the correction factor applied for a particular speed (e.g. correction/kph). In this example, the correction factor K, and indeed the correction characteristic 300, is based at least partly on the aerodynamics of the vehicle 100. For a given vehicle 100, the additional load applied on a rear axle 107, and so the rear tyres, may be considered to increase with vehicle speed and initial static load. Of course, in other examples, the correction factor additionally or alternatively may be based on driving conditions, such as acceleration/deceleration, vehicle gradient, or the like. The above correction characteristic/factor is given by way of an example only.

In Figure 3b, in use, and when the vehicle 100 is initially stopped (e.g. at a bus stop), the load calculated from the sensor arrangement 220 may be considered to be an approximation of the static load of the vehicle 100. However, due to the nature of passenger service vehicles, in which passengers move around the vehicle or in which suspension is raised and lowered, the actual static load may be somewhat different. However, at least initially an approximate static load, L_s, can be calculated. This observed "load" is passed to the vehicle controller 230 in the same manner as in Figure 3a, and any limiting of speed or the like may be initiated. However, here, this load L_s is also passed to the correction device 250. Using a correction characteristic - one of which is exemplified in Figure 4 - together with the vehicle speed, the correction device is configured to provide a correction factor K to the travelling load for that particular speed. In turn, the tyre-condition system 210 can calculate an approximate static load at the tyres based on the determined travelling load at the tyres (e.g. via a suspension monitor), together with the correction factor K. For example, when the vehicle 100 is stationary, it is likely that no correction factor is applied. However, as the vehicle 100 begins to move, the correction factor may be used to modify the determined load at the tyres in order to provide an approximate static load. Such modification may include reducing the determined travelling load by a defined amount (e.g. 5 kg/kph, or the like). In other words, as the vehicle 100 increases in speed and the observed load at the axle increases, a correction can be applied to modify that load to provide an approximate static load. As is shown in Figure 3b, an optional feedback system 270 may be used such that the calculated approximate static load is fed to the correction device 250 so as to refine the correction factor K as the vehicle 100 is moving. In such a way, correction to the initially calculated static load when the vehicle 100 was stationary can be corrected for any passenger movement, suspension use, reduction in weight due to fuel usage, etc., that would otherwise unduly affect initial readings, as outlined above.

As above, the control system 200, and vehicle controller 230, can be configured to limit maximum speed, or otherwise control the speed or speed characteristics of the vehicle 100, when a particular threshold of approximate static load has been met (e.g. exceeded). As above, having such control over the vehicle speed, etc., depending on load, may permit selection of alternative tyre configurations to be used, and/or other more efficient driving conditions to be implemented. This may improve fuel efficiency and improve vehicle safety.

While in some examples, the tyre-condition system 210 may be in communication with the vehicle controller 230, in the manner shown in Figure 3a or 3b, it will nevertheless be appreciated that in further examples the tyre-condition system 210 may additionally or alternatively be in communication with a user interface, or the like, in order present, for example, a calculated approximate static load to a user (e.g. driver). Such a system may be useful in vehicles beyond passenger service vehicles. Such other variable load vehicles may include refuse vehicles, dumper vehicles, or the like. Further, while in some examples, the vehicle controller 230 may be used solely or principally to control speed characteristics based on the travelling load, whether directly or using a calculated approximate static load, nevertheless in further examples the vehicle controller 230 may be configured to control speed characteristics in alternative or additional ways.

Consider now Figure 5, which shows an example of a vehicle controller 430 for use with the systems of Figures 3a and 3b. Here, the vehicle controller 430 is in communication with a first tyre-condition system 410 in a similar manner to that described in relation to Figure 3a or 3b. Here, the controller 430 further receives data 415 associated with the threshold load/speed values for the particular tyre configuration used at the vehicle 100 - in other words, the maximum safe speed for a particular load, such as static load. As explained above, a speed characteristic such as a maximum speed may be set based on this received data.

However, here, the vehicle controller 430 is further in communication with a second tyre-condition system 440, configured to determine a tyre condition of the vehicle 100. In this example, that further tyre condition is different from that determined by the first tyre-condition system 410. Here, the second tyre-condition system 440 is configured to determine tyre pressures at one or more tyres of the vehicle 100. In the event that a tyre pressure is identified by the second tyre-condition system 440 as being below a particular threshold, then the vehicle controller 430 is configured to control speed characteristics of the vehicle based upon the determined tyre condition.

In this example, an initial (likely lower) speed limit may be set by the controller 430 if an identified tyre condition shows that one or more of the tyres has a particular pressure (e.g. below an acceptable threshold). Therefore, if the controller 430 identifies that one tyre has particular low pressure, then the controller 430 may set the vehicle speed limit such that only a reduced speed, even limp-home speed, may be used. It will be appreciated that while such monitoring may be less valuable when using a multiple tyre configuration 107a, 107b as shown in Figure 2, nevertheless where these multiple tyres are replaced with single tyres, closer monitoring may be helpful in order to avoid unwanted stability issues. Further, in this example, while the vehicle controller 430 is configured to "set" one or more speed characteristics of a vehicle in the event of particular determined vehicle usage (e.g. determined and/or calculated load/pressures at the tyres), the vehicle controller 430 is nevertheless also configured to "unset" subsequently the one or more speed characteristics in the absence of the determined vehicle usage. However, in doing so, such "un-setting" occurs when a determined driving condition 450 has been observed by the vehicle controller 430.

Here, that driving condition 450 is the reduction in speed, from the set limit, by a particular threshold amount - in this example, 10 kph.

In other similar words, after a speed characteristic has been set (e.g. speed limit), the controller 430 may be configured to remove that set speed characteristic when the speed has dropped below a predefined threshold. It has been observed that drivers of vehicles 100, when in a restricted speed mode of operation, may continue to depress the accelerator, or the like, to the maximum. Of course, in times of restricted or limited speed, such depression is unlikely to have any effect. However, in that absence of a limit (e.g. when the load or pressure conditions change), then having the accelerator fully depressed may unsafely cause the vehicle to speed forward unexpectedly. This may be hazardous for the vehicle 100 and the occupants. Therefore, by ensuring there is a reduction in speed prior to un-setting the speed limit, such scenarios can be avoided. It will be appreciated that such vehicle control may be used beyond the control systems described here, and may have applicability in other vehicles having speed characteristic settings.

While in the above example two tyre-condition systems 440, 410 have been described, it will be appreciated that more or fewer may be provided with the above described control system. It will also be appreciated that each tyre-condition system may be configured to determine the tyre condition of one or more tyres (e.g. all tyres), whether that be directly, such as monitoring tyre pressure of a particular tyre, or indirectly such as monitoring axle loads, and determining tyre loads accordingly. In similar words, each tyre-condition system may be in communication with a sensor arrangement that measures a tyre condition directly, or at least the measured data can be used to determine a tyre condition. In some examples, the tyre-condition system may be comprised with, and in communication with, such sensor arrangements. It will be appreciated that any of the aforementioned systems, sensors, etc. or the like may have other functions in addition to the mentioned functions, and that these functions may be performed by the same systems/sensors, etc. Further, it will be appreciated that aspects of the above systems may be providing during initial assembly of vehicles 100, or may be retrofit to such vehicles. In either case, the system may utilise existing sensors, or the like, to obtain tyre condition data (e.g. using tyre pressure sensors, and/or suspension pressure sensors, etc.).

The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the invention may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.

Claims

CLAIMS:

1. A control system for a passenger service vehicle, comprising:

at least one tyre-condition system in communication with a sensor arrangement and configured to determine a condition of a tyre of the vehicle;

a vehicle controller, in communication with the tyre-condition system, and being configured to control speed characteristics of the vehicle based upon the determined tyre condition.

2. The control system of claim 1 , wherein the vehicle controller is configured to limit the speed of the vehicle based on the determined tyre condition.

3. The control system according to claim 1 or 2, wherein the vehicle controller is configured to control speed characteristics when a particular threshold associated with the tyre condition has been exceeded.

4. The control system according to claim 3, wherein the threshold relates to load ratings of the tyre being used on the vehicle, and/or a particular tyre pressure.

5. The control system according to any of the claims 1 to 4, wherein the tyre- condition system is configured to determine, as a tyre condition, a travelling load at at least one tyre of the vehicle.

6. The control system according to claim 5, wherein the tyre-condition system comprises a correction device configured to allow the control system to calculate an approximate static load at the tyre of the vehicle based on a determined travelling load at the tyre, and wherein the vehicle controller is configured to control speed characteristics of the vehicle using a calculated approximate static load at the tyre.

7. The control system according to claim 6, wherein the correction device is configured to allow the control system to calculate an approximate static load using a correction factor associated with the vehicle.

8. The control system according to claim 7, wherein the correction factor is based, at least in part, on the aerodynamics of the vehicle.

9. The control system according to claim 7 or 8, wherein the correction device is configured to use a present speed of the vehicle together with the initial static load, and/or a subsequently calculated approximate static load, in order to determine the correction factor.

10. The control system according to any of the claims 1 to 9, wherein the tyre- condition system is configured to determine, as a tyre condition, the pressure of the tyre.

1 1 . The control system according to any of the claims 1 to 10, wherein the system comprises a first tyre-condition system configured to determine, as a tyre condition, a travelling load of the tyre, and a second tyre-condition system configured to determine, as a tyre condition, the pressure of the tyre.

12. The control system according to claim 1 1 , wherein the vehicle controller is configured to control the speed characteristics of the vehicle based on the determined tyre conditions from both first and second tyre-condition systems.

13. The control system according to any of the claims 1 to 12, wherein the vehicle controller is configured to set one or more speed characteristics of a vehicle in the event of a particular tyre condition and to unset subsequently the one or more speed characteristics in the absence of the determined tyre condition, but when a determined driving condition has been observed by the vehicle controller.

14. The control system according to claim 13, wherein the vehicle controller is configured to unset one or more speed characteristics when the speed of the vehicle has been reduced by a particular threshold amount.

15. The control system according to any of the claims 1 to 14 specifically configured for use with double-deck passenger service vehicles.

16. The control system according to any of the claims 1 to 15 configured to be retrofitted to vehicles.

17. A control system for a vehicle comprising:

at least one tyre-condition system in communication with a sensor arrangement, and configured to determine from data received from the sensor arrangement, during travel of the vehicle, a travelling load at a tyre of the vehicle; and the tyre-condition system further comprising a correction device configured to allow the control system to calculate an approximate static load at the tyre based on a determined travelling load at the tyre.

18. The control system of claim 17, further comprising a vehicle controller, in communication with the tyre-condition system, and configured to control speed characteristics of the vehicle based on the calculated approximate static load.

19. A control system for a vehicle comprising:

a vehicle controller configured to set one or more speed characteristics of a vehicle in the event of particular determined vehicle usage, and wherein the vehicle controller is configured to unset subsequently the one or more speed characteristics in the absence of the determined vehicle usage, when a determined driving condition has been observed by the vehicle controller.

20. The control system according to claim 19, wherein the vehicle controller is configured to unset one or more speed characteristics when the speed of the vehicle has been reduced by a particular threshold amount.

21 . A method for controlling a passenger service vehicle, comprising:

determining, during travel of the vehicle, a tyre condition of a tyre of the vehicle; and

controlling speed characteristics of the vehicle based upon the determined tyre condition.

22. The method according to claim 21 , wherein the method comprises limiting the speed of the vehicle based on the determined tyre condition.

23. The method according to claim 21 or 22, wherein the method comprises controlling speed characteristics when a particular threshold associated with the tyre condition has been exceeded.

24. The method according to claim 23, wherein the threshold relates to load ratings of the tyre being used on the vehicle, and/or a particular tyre pressure.

25. A method for controlling a vehicle comprising:

determining, during travel of the vehicle, a travelling load associated with a tyre of the vehicle; and

calculating an approximate static load associated with the tyre based on the determined travelling load.

26. A method for controlling a vehicle comprising:

setting one or more speed characteristics of a vehicle in the event of particular determined vehicle usage and

un-setting subsequently the one or more speed characteristics in the absence of the determined vehicle usage, when a determined driving condition has been observed.

27. A passenger service vehicle comprises a control system accordingly to any of the claims 1 to 20.

28. The vehicle according to claim 27, wherein the vehicle is a double-deck vehicle comprising two axles, each axle having two tyres for contact with the road.

29. The vehicle according to claim 28, wherein the tyres at at least one axle have a tyre width of greater than 350 mm, such as roughly between 400 mm and 500 mm.

30. The vehicle according to claim 29, wherein at least the rear axle comprises only two super-single tyres, each having a tyre width of 400 mm, or greater.