Vehicle suspension systems

Abstract

A ride-height adjustment system for a vehicle. The system has a first detector, to detect a preliminary end-of-journey (EOJ) event, such as seat belt unbuckling or ignition switch-off. A controller adjusts the vehicle's suspension system in a first movement in response to detection of the preliminary EOJ event, to change the ride height of the vehicle towards an access ride height of the vehicle. The access ride height is a predetermined ride height that facilitates egress from and entrance to the vehicle. A second detector detects opening of a door of the vehicle. When the ride height of the vehicle remains different from the access ride height after the first movement, the controller adjusts the suspension system in a second movement in response to the door-opening detection. This further changes the ride height of the vehicle towards the access ride height of the vehicle.

Claims

1. A ride-height adjustment system for a vehicle, the system comprising: a suspension system, which is adjustable to change a ride height of the vehicle in which the suspension system is fitted; a first detector, to automatically detect a preliminary end-of-journey (EOJ) event indicative of a preliminary expectation of an end of a journey; a controller, to adjust the suspension system in a first movement in response to automatic detection of said preliminary EOJ event, to change the ride height of the vehicle towards an access ride height of the vehicle, which access ride height is a predetermined ride height that facilitates egress from and entrance to the vehicle; and a second detector, to automatically detect a decisive EOJ event indicative of a decisive expectation of the end of the journey, wherein, when the ride height of the vehicle remains different from the access ride height after said first movement, the controller is adapted to further adjust the suspension system in a second movement in response to said decisive EOJ event detection, to further change the ride height of the vehicle towards said access ride height of the vehicle.

2. A ride-height adjustment system as claimed in claim 1, in which said first and second detectors comprise: an electronic processor having an electrical input for receiving signals indicative of said preliminary EOJ event and said decisive EOJ event; and an electronic memory device electrically coupled to the electronic processor and having instructions stored therein; wherein the processor is configured to access the memory device and execute the instructions stored therein such that the processor is operable in response to said preliminary EOJ event and decisive EOJ event to adjust the suspension system in said first and second movements.

3. A ride-height adjustment system as claimed in claim 1, in which said decisive EOJ event comprises opening of a door of the vehicle.

4. A ride-height adjustment system as claimed in claim 1, in which said controller is arranged to cease said adjustment of the suspension system in said second movement, said cessation of said adjustment occurring one of (1) after a predetermined maximum change of ride height has occurred, (2) after a maximum period of time has elapsed since said decisive EOJ event detection, and (3) when the vehicle reaches said access ride height.

5. A ride-height adjustment system as claimed in claim 4, in which said second movement is ceased after between 2 and 4 seconds, and/or after between 25 and 40 mm of change in ride height of the vehicle.

6. A ride-height adjustment system as claimed in claim 1, in which said controller is arranged to cease said adjustment of the suspension system in said first movement after a predetermined maximum change of ride height has occurred and/or after a maximum period of time has elapsed since said detection of said preliminary EOJ event.

7. A ride-height adjustment system as claimed in claim 6, in which said first movement is ceased after between 15 and 25 mm of change in ride height of the vehicle.

8. A ride-height adjustment system as claimed in claim 1, in which said changes of ride height are lowerings of the ride height.

9. A ride-height adjustment system as claimed in claim 1, in which said preliminary EOJ event is one of: an ignition system of the vehicle being switched off; and one or more seat belts of the vehicle being unbuckled.

10. A ride-height adjustment system as claimed in claim 1, further comprising a third detector to detect one or more inhibit parameters of the vehicle to prevent the controller from adjusting the suspension system in said first and/or second movements.

11. A ride-height adjustment system as claimed in claim 10, in which an inhibit parameter comprises one or more of: a) detection of a previous event of the ignition system being switched off without a subsequent door opening event before re-engagement of the ignition; b) detection of a seat belt of the vehicle being unbuckled without a subsequent corroborative event occurring; c) detection of inadequate capacity of the suspension system to reverse the change in vehicle ride height should manual intervention of the ride-height adjustment system be effected; d) detection of uneven ground or sloped ground on which the vehicle is positioned; e) detection of ground or jack contact of a body of the vehicle; f) detection of vehicle wading; and g) detection of towing.

12. A ride-height adjustment system as claimed in claim 11, in which said corroborative event is selected from: the vehicle coming to a halt after said seat belt of the vehicle has been unbuckled within a predetermined period of time, and a vehicle EOJ prediction system predicts an EOJ event with a required level of confidence.

13. A vehicle incorporating a ride-height adjustment system as claimed in claim 1.

14. A method of adjusting the ride height of a vehicle comprising the steps of: providing the vehicle with a suspension system that is adjustable to change a ride height of the vehicle in which the suspension system is fitted; automatically detecting a preliminary end-of-journey (EOJ) event indicative of a preliminary expectation of an end of a journey; using a controller, adjusting the suspension system in a first movement in response to said automatic detection of said preliminary EOJ event, to change the ride height of the vehicle towards an access ride height of the vehicle, which access ride height is a predetermined ride height that facilitates egress from and entrance to the vehicle; automatically detecting a decisive EOJ event indicative of a decisive expectation of the end of the journey; and when the ride height of the vehicle remains different from the access ride height after said first movement, further adjusting the suspension system in a second movement in response to said decisive EOJ event detection, to further change the ride height of the vehicle towards said access ride height of the vehicle.

15. A method as claimed in claim 14, in which: said decisive EOJ event comprises opening of a door of the vehicle; and/or said preliminary EOJ event is one of: an ignition system of the vehicle being switched off; and one or more seat belts of the vehicle being unbuckled.

16. A method as claimed in claim 14, in which said adjustment of the suspension system comprises at least one of: ceasing in said second movement after a predetermined maximum change of ride height has occurred, said cessation of said second movement occurring one of (1) after a maximum period of time has elapsed since said decisive EOJ event detection, and (2) when the vehicle reaches said access ride height; and ceasing in said first movement after one of (1) a predetermined maximum change of ride height has occurred, and (2) a maximum period of time has elapsed since said detection of said preliminary EOJ event.

17. A method as claimed in claim 14, further comprising detecting inhibit parameters of the vehicle and, on detection of one or more of said inhibit parameters, preventing said adjusting of the suspension system in said first and/or second movements.

18. A method as claimed in claim 17, in which an inhibit parameter comprises one or more of: a) detection of a previous event of the ignition system being switched off without a subsequent door opening event before re-engagement of the ignition; b) detection of a seat belt of the vehicle being unbuckled without a subsequent corroborative event occurring; c) detection of inadequate capacity of the suspension system to reverse the change in vehicle ride height should manual intervention of the ride-height adjustment system be effected; d) detection of uneven ground or sloped ground on which the vehicle is positioned; e) detection of ground or jack contact of a body of the vehicle; f) detection of vehicle wading; and g) detection of towing.

19. A method as claimed in claim 18, in which said corroborative event is selected from: the vehicle coming to a halt after said seat belt of the vehicle has been unbuckled within a predetermined period of time, and a vehicle EOJ prediction system predicts an EOJ event with a required level of confidence.

20. An electronic controller for a vehicle having a storage medium associated therewith storing instructions that when executed by the controller causes the ride height of the vehicle to be adjusted in accordance with the method of claim 14.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention are further described hereinafter, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 is plan schematic view of a vehicle incorporating a system in accordance with an example of the present invention;

(3) FIG. 2 is a block diagram showing a ride height adjustment system in accordance with an embodiment of the present invention; and

(4) FIG. 3 is a schematic flow diagram of the steps involved in a system in accordance with an example of the present invention.

DETAILED DESCRIPTION

(5) In FIGS. 1 and 2, a vehicle 10 comprises wheels 12 connected to a body 14 of the vehicle via an adjustable suspension system 16, which may comprise an air-powered system of known type and requiring no further elucidation here. However, by operating the suspension system 16, the ride height of the vehicle 10, being the height of the body 14 above the ground when resting on its wheels 12 on level ground, can be raised or lowered. The raising and lowering may be done manually with a switch 20. The switch 20 may be connected directly to the suspension system 16, as shown in the block diagram in FIG. 2, or it may be connected to a controller 22 of an automatic ride-height adjustment system 100 in accordance with the present invention, as shown in FIG. 1. The controller 22 has a memory 24 in which instructions are stored for operating the controller. The controller also has a plurality of inputs 26 which cause it to operate the suspension system in accordance with the instructions in the memory 24.

(6) The inputs 26 comprise: Manually operable switch 20 (in FIG. 1); An ignition-On/Off detector 28; Door opening detectors 30 (only two shown in FIG. 1, although a detector could be used on any and all passenger doors; Seat belt Buckled/Unbuckled detectors 32 (again, only two shown but more may be employed); End-of-Journey prediction system 34 Other detectors (not shown but described further below)

(7) Turning to FIG. 3, the following procedure may be followed in the course of a vehicle journey in which the system 100 is fitted and when the journey approaches its end:

(8) At the Start 50, the first step is to detect if the Auto-Access vehicle ride height adjustment system 100 is enabled. Enablement may be achieved through a vehicle set-up menu (not described herein) or some other appropriate means. If it is not enabled, the entire remaining process is avoided and the system maintains the suspension in its set position. The set position depends on the vehicle and may comprise any one of Sport, Road, Off-Road, Extended or other setting including Terrain Response (TM), an automatic system (not described further herein) which automatically sets the suspension (among other things) in response to changes detected in the terrain being traversed by the vehicle. Sport-mode may comprise a low ride height to lower the centre of gravity to facilitate fast cornering. Road-mode may be considered a normal mode at intermediate ride height for maximum comfort and handling on metalled surfaces. Off-Road-mode may comprise a relatively high ride height to give ground clearance on rough terrain. Extended-mode may be at maximum ride height for use over extremely rough terrain or when wading in deep water.

(9) If the system is enabled, the controller first checks 62 to establish the current state of the suspension. If not in a certain condition, the system does not proceed any further until it is at normal or a Speed Lowered height (which may be a lowered height for high speed of SUV type vehicles, where normal height is still relatively highly elevated). When normal or speed lowered suspension height is detected, the doors are checked in step 64 to establish if they are open. If the doors are open, then this is because the system has not anticipated the end of the journey which has occurred unexpectedly. In this scenario, in step 66, all the conditions for lowering the suspension are checked and provided these are affirmative, the system, in step 68 lowers the suspension in one of the following ways:

(10) 1. Go to Full Access height

(11) 2. Go to defined height close to Full Access height

(12) 3. Go towards Full Access height for defined time period, e.g. 3 seconds.

(13) Which mode is selected depends on the setting of the suspension when step 66 is invoked and how the system of the invention is set. For example, it may be that, in this mode, with the doors open, only a predefined drop of height (for example 35 to 40 mm) will be permitted, which may not be sufficient to reach Full Access height (Option 2), or the lowering will only occur for 3 seconds (Option 3) which may be considered a safe limit to minimize the possibility of an occupant of the vehicle trapping themselves under a lowering door. However, it may be that the suspension is already low and the vehicle can be lowered to its Full Access height (Option 1). Full Access height is, of course, the suspension position that most easily facilitates egress of occupants from the vehicle, which may a fully lowered position, perhaps 50 mm below normal operating position of the vehicle body.

(14) After step 68, the driver may still manually select Full Access height in step 70, which if selected is effected in step 72. And, whether or not he/she has done so, should a condition be detected in step 74 that the Auto-Access system of the present invention should be exited, the suspension is changed to its normal height in step 76, or such other height as set or determined by the Terrain Response (TM) system. At this point, the system reverts back to the Start 50.

(15) Returning to step 64, if the doors are not opened when the system is in Auto-Access mode and the suspension is in its normal or Speed Lowered position, then step 78 detects whether or not an EOJ event is about to happen, that is, whether the system determines that passengers are about to disembark. This occurs when, for example, the seat belts are unbuckled or the ignition is disabled or when an EOJ event predictor determines that an EOJ event is about to occur with sufficient probability. If none of these conditions prevail, the system returns to the Start 50 but when they do and all Auto-Access conditions are satisfied (tested in step 80, which if not satisfied reverts the system back to the Start 50) the system lowers the suspension by a first amount in step 82. That amount may be 18 mm below normal ride height.

(16) The speed of the vehicle is then tested in step 84 and if it exceeds 40 kph (or another predetermined speed), the system reverts the suspension to normal ride height in step 86 and returns the system to the Start 50. However, if the speed does not exceed 40 kph, the state of doors of the vehicle is tested in step 88. If they are not open, the system cycles back to the speed test of step 84 until such time as the doors are opened. If, then, all the Auto-Access conditions are satisfied, tested in step 90, the suspension is lowered to its Full Access height in step 72, whereupon the system follows the procedure described above. However, if any one of those conditions are not satisfied, the system reverts to the speed test in step 84.

(17) Steps 66, 74, 80 and 90 are all the same step of testing that the vehicle is in a condition where the Auto Access can be invoked. These have been described above and are listed below under the title Precautions. This is a non-limiting non-exhaustive list of vehicle states that may or may not be required to pertain.

(18) In summary:

(19) Auto Access High Level Functionality Description

(20) If vehicle is moving slowly (<2 kph) AND suspension at Normal On-Road height AND (any seat belt disconnected or ignition turned off) THEN lower suspension by 18 mm When a door is opened, then lower to full Access height (50 mm below Normal height) If the 18 mm lowered suspension height has not been activated before opening a door then the suspension will lower to an Access height 35 mm to 40 mm below Normal height instead
Precautions
The Auto Access functionality may include the following precautions: Feature can be turned on and off by the customer Height change while doors are open only allows a limited height change (up to 40 mm) or a limited time (3 seconds) Lowering to access when doors opened is only available for a limited time after car comes to rest (90 seconds) If vehicle is stationary longer than this then it must be moved or the Auto Access function re-enabled Auto Access is disabled on uneven or sloping ground Auto Access is disabled if the vehicle has not moved since the ignition was switched on. This step protects against inadvertent change of the suspension if the engine is just switched on and off, and at the immediate start of a journey Auto Access is not enabled unless there are sufficient pneumatic resources to re-lift the suspension. This is satisfied if the system reservoir pressure is above a threshold or compressor is sufficiently cool to be instantly activated Auto Access will be disabled if the air suspension has detected wading, trailing, or body grounding conditions (this will result in a reduction of the pressure exerted on the system through one or more of the wheels) Auto Access can be disabled in manually selected Terrain Response modes (high range and low range disable flags are independently tunable) If Auto Access has been activated, then suspension re-lifting is allowed up to 3 minutes after the ignition is turned off Height changes are normally disabled 90 seconds after ignition is switched off or when the driver's door is opened, whichever comes first During or after an Auto Access activation a single, short press on the suspension raise switch will make the suspension height go straight back to Normal height Suspension raising (and lowering) may be enabled when doors are open, provided the switches are pressed and held (under normal circumstances it is undesirable to permit raising and lowering while the doors are open, but in the event that Auto Access lowers the vehicle onto a person or obstacle it is necessary to enable it to be lifted off without needing to close the doors (which might not be possible)

(21) Although described herein in detail as lowering the suspension system from a higher level to an access level, for example as appropriate for SUV or other high vehicles, when the invention is used in a sports car or performance vehicle it will be appreciated that the suspension may be raised to access height, i.e. the first movement causes an initial raising of the suspension to an intermediate level and the second movement causes a second raising of the suspension to the full access height so that the vehicle is not so low, thereby facilitating a driver or passenger when egressing from the vehicle. In such a vehicle wherein the suspension is raised to access height as opposed to lowered the invention will operate as described herein except in so far as it will be raised in two stages as opposed to lowered in two stages when transitioning from normal height to access height.

(22) Throughout the description and claims of this specification, the words comprise and contain and variations of them mean including but not limited to, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

(23) Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.