CA3088369A1 - Electronic suspension control system for a vehicle - Google Patents
Electronic suspension control system for a vehicle Download PDFInfo
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- CA3088369A1 CA3088369A1 CA3088369A CA3088369A CA3088369A1 CA 3088369 A1 CA3088369 A1 CA 3088369A1 CA 3088369 A CA3088369 A CA 3088369A CA 3088369 A CA3088369 A CA 3088369A CA 3088369 A1 CA3088369 A1 CA 3088369A1
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- suspension
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- vehicle
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- air spring
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- 239000000725 suspension Substances 0.000 title claims abstract description 212
- 238000000034 method Methods 0.000 claims abstract description 29
- 238000012935 Averaging Methods 0.000 claims abstract description 6
- 230000001133 acceleration Effects 0.000 claims description 65
- 238000009530 blood pressure measurement Methods 0.000 claims description 16
- 238000005259 measurement Methods 0.000 claims description 10
- 230000003247 decreasing effect Effects 0.000 claims description 6
- 238000012544 monitoring process Methods 0.000 claims description 6
- 238000004891 communication Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 5
- 230000001276 controlling effect Effects 0.000 description 3
- 230000009977 dual effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 230000009194 climbing Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
- B60G17/02—Spring characteristics, e.g. mechanical springs and mechanical adjusting means
- B60G17/04—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics
- B60G17/052—Pneumatic spring characteristics
- B60G17/0523—Regulating distributors or valves for pneumatic springs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
- B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
- B60G17/018—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the use of a specific signal treatment or control method
- B60G17/0182—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the use of a specific signal treatment or control method involving parameter estimation, e.g. observer, Kalman filter
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
- B60G2202/10—Type of spring
- B60G2202/15—Fluid spring
- B60G2202/152—Pneumatic spring
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2204/00—Indexing codes related to suspensions per se or to auxiliary parts
- B60G2204/40—Auxiliary suspension parts; Adjustment of suspensions
- B60G2204/47—Means for retracting the suspension
- B60G2204/4702—Means for retracting the suspension pneumatically
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2300/00—Indexing codes relating to the type of vehicle
- B60G2300/40—Variable track or wheelbase vehicles
- B60G2300/402—Extra load carrying wheels, e.g. tag axles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
- B60G2400/10—Acceleration; Deceleration
- B60G2400/104—Acceleration; Deceleration lateral or transversal with regard to vehicle
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
- B60G2400/10—Acceleration; Deceleration
- B60G2400/106—Acceleration; Deceleration longitudinal with regard to vehicle, e.g. braking
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
- B60G2400/25—Stroke; Height; Displacement
- B60G2400/252—Stroke; Height; Displacement vertical
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
- B60G2400/50—Pressure
- B60G2400/51—Pressure in suspension unit
- B60G2400/512—Pressure in suspension unit in spring
- B60G2400/5122—Fluid spring
- B60G2400/51222—Pneumatic
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
- B60G2400/60—Load
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
- B60G2400/60—Load
- B60G2400/61—Load distribution
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2500/00—Indexing codes relating to the regulated action or device
- B60G2500/20—Spring action or springs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
- B60G2600/02—Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2800/00—Indexing codes relating to the type of movement or to the condition of the vehicle and to the end result to be achieved by the control action
- B60G2800/70—Estimating or calculating vehicle parameters or state variables
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2800/00—Indexing codes relating to the type of movement or to the condition of the vehicle and to the end result to be achieved by the control action
- B60G2800/70—Estimating or calculating vehicle parameters or state variables
- B60G2800/702—Improving accuracy of a sensor signal
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Vehicle Body Suspensions (AREA)
Abstract
A system and method are provided for configuring suspension ratios in a multi-rear axle vehicle, the vehicle having a drive axle suspension and at least one tag axle suspension, each suspension having one or more air springs. A further system and method are provided for averaging fluctuations in suspension height or air pressure readings of one or more air spring suspensions in a multi-rear axle vehicle and for performing an adjustment cycle series of steps for adjusting the suspension height and air spring pressure readings. Finally, a method is provided for configuring suspension ratios in a multi-rear axle vehicle, the vehicle having a drive axle suspension and at least one tag axle suspension, and for adjusting the air suspension pressures.
Description
ELECTRONIC SUSPENSION CONTROL SYSTEM FOR A VEHICLE
FIELD
The present disclosure relates to a system for electronically controlling axle suspension of a vehicle with multiple rear axles, to allow for optimization of load distribution on the vehicle.
BACKGROUND
Vehicles having multiple rear axles are often used to carry heavy loads, and can include semi-trailers, large busses and other large load carrying vehicles.
Typically such vehicles have a front steering, non-driving axle which imparts steering control; a drive axle behind the steering axle, to impart driving force; and one or more tag axles behind the drive axle to support the weight of the vehicle chassis and loads carried therein.
Balance and control of suspension in each axle and between the axles is needed to provide load support, traction and control of the vehicle as well as to provide a comfortable ride. While in some cases, such suspensions are mechanical spring suspensions, in other cases air spring suspension may be used, which are controllable.
The ride height, or height of the body of the vehicle with respect to the road can also be manipulated by adjusting axle suspensions.
It is also often important to ensure that suspension air pressure readings are in fact accurate. Many factors including driving conditions and acceleration state can affect the accuracy of air pressure and ride height readings and these need to be taken into account when ensuring suspension and ride height data is correct.
Applicant's own US 7,066,474 and US 9,452,655 teach methods of suspension and level control in recreation vehicles employing air suspension systems.
Applicant's CA 2,422,864C teaches a suspension and level control system to independently control inflation and deflation of left and right front and rear air-springs in a parallel pneumatic circuit. While control of air pressure in each air cushion of each air Date Recue/Date Received 2020-07-29 spring is controlled individually, there is no means of considering relative air pressures between air spring suspensions.
US20060267296A1 teaches a system in which the height of the air bag is sensed by a pair of tilt sensors, sensing tilt of its location with respect to gravity, and the difference in tilt indicates air bag height. The output of the tilt sensors may be filtered, and a motion detector allows rapid filling or dumping of air bags independent of filtering of tilt sensor signals. Control of the vehicle air suspension can also be based upon inputs from one or more air bag pressure sensors.
US6523625B2 teaches a system and method for improving the traction of a vehicle using weight distribution control to improve wheel to driving surface friction. Actuators and controllers adjust suspension members in a selectable predetermined manner. The selection can be based on operator preference, vehicle operating mode, or a sensed loss of traction. The driven axle carries a drive axle maximum rated load in order to maximize drive wheel traction at all times.
W02000000360A1 teaches an air suspension assembly tied to an antilock/traction controller. Thus, in response to a differential traction control event, pressurized air to air bags associated with the suspension assembly is regulated to transfer greater vehicle load to the drive axle.
However, a need still exists for a means to determine whether air pressure and .. suspension height readings from the air springs while the vehicle is in motion can be relied upon as accurate. A need also exists for means to control air suspension pressures between axles of a multiple axle vehicle and for a system that can take into account driving conditions, acceleration, speed, load and ride height in controlling the relative air pressure between air suspensions of each axle.
SUMMARY
A system is provided for configuring suspension ratios in a multi-rear axle vehicle, said vehicle having a drive axle suspension and at least one tag axle suspension, each suspension comprising one or more air springs. The system comprises:
FIELD
The present disclosure relates to a system for electronically controlling axle suspension of a vehicle with multiple rear axles, to allow for optimization of load distribution on the vehicle.
BACKGROUND
Vehicles having multiple rear axles are often used to carry heavy loads, and can include semi-trailers, large busses and other large load carrying vehicles.
Typically such vehicles have a front steering, non-driving axle which imparts steering control; a drive axle behind the steering axle, to impart driving force; and one or more tag axles behind the drive axle to support the weight of the vehicle chassis and loads carried therein.
Balance and control of suspension in each axle and between the axles is needed to provide load support, traction and control of the vehicle as well as to provide a comfortable ride. While in some cases, such suspensions are mechanical spring suspensions, in other cases air spring suspension may be used, which are controllable.
The ride height, or height of the body of the vehicle with respect to the road can also be manipulated by adjusting axle suspensions.
It is also often important to ensure that suspension air pressure readings are in fact accurate. Many factors including driving conditions and acceleration state can affect the accuracy of air pressure and ride height readings and these need to be taken into account when ensuring suspension and ride height data is correct.
Applicant's own US 7,066,474 and US 9,452,655 teach methods of suspension and level control in recreation vehicles employing air suspension systems.
Applicant's CA 2,422,864C teaches a suspension and level control system to independently control inflation and deflation of left and right front and rear air-springs in a parallel pneumatic circuit. While control of air pressure in each air cushion of each air Date Recue/Date Received 2020-07-29 spring is controlled individually, there is no means of considering relative air pressures between air spring suspensions.
US20060267296A1 teaches a system in which the height of the air bag is sensed by a pair of tilt sensors, sensing tilt of its location with respect to gravity, and the difference in tilt indicates air bag height. The output of the tilt sensors may be filtered, and a motion detector allows rapid filling or dumping of air bags independent of filtering of tilt sensor signals. Control of the vehicle air suspension can also be based upon inputs from one or more air bag pressure sensors.
US6523625B2 teaches a system and method for improving the traction of a vehicle using weight distribution control to improve wheel to driving surface friction. Actuators and controllers adjust suspension members in a selectable predetermined manner. The selection can be based on operator preference, vehicle operating mode, or a sensed loss of traction. The driven axle carries a drive axle maximum rated load in order to maximize drive wheel traction at all times.
W02000000360A1 teaches an air suspension assembly tied to an antilock/traction controller. Thus, in response to a differential traction control event, pressurized air to air bags associated with the suspension assembly is regulated to transfer greater vehicle load to the drive axle.
However, a need still exists for a means to determine whether air pressure and .. suspension height readings from the air springs while the vehicle is in motion can be relied upon as accurate. A need also exists for means to control air suspension pressures between axles of a multiple axle vehicle and for a system that can take into account driving conditions, acceleration, speed, load and ride height in controlling the relative air pressure between air suspensions of each axle.
SUMMARY
A system is provided for configuring suspension ratios in a multi-rear axle vehicle, said vehicle having a drive axle suspension and at least one tag axle suspension, each suspension comprising one or more air springs. The system comprises:
2 Date Recue/Date Received 2020-07-29 a. a manifold comprising one or more manifold lines for supplying compressed air to or exhausting air from the one or more air springs of the drive axle suspension and tag axle suspensions;
b. at least one supply valve on the manifold lines between each air spring and the supply of compressed air c. at least one exhaust valve on the manifold lines between each air spring and the exhaust;
d. at least one pressure transducer for taking pressure measurements from the one or more manifold lines;
e. one or more ride height sensors for monitoring ride height of the vehicle;
and f. a processor receiving signals containing pressure measurements from the at least one pressure transducer and ride height inputs from the ride height sensors, and comprising one or more algorithms for calculating the suspension ratio of air pressure between the one or more tag suspensions and the drive suspension, determining a driving condition based on ride height inputs and comparing the calculated suspension ratio against a predetermined suspension ratio of air pressure for said driving condition, said processor being in communication to open or close said one or more valves to adjust air pressure in any one or more of said one or more air springs to set the suspension ratio of air pressure to the predetermined suspension ratio of air pressure.
A method is further provided for configuring suspension ratios in a multi-rear axle vehicle, said vehicle having a drive axle suspension and at least one tag axle suspension, each suspension comprising one or more air springs. The method comprises the steps of:
a) providing the system described above;
b) taking pressure measurements from the one or more manifold lines;
b. at least one supply valve on the manifold lines between each air spring and the supply of compressed air c. at least one exhaust valve on the manifold lines between each air spring and the exhaust;
d. at least one pressure transducer for taking pressure measurements from the one or more manifold lines;
e. one or more ride height sensors for monitoring ride height of the vehicle;
and f. a processor receiving signals containing pressure measurements from the at least one pressure transducer and ride height inputs from the ride height sensors, and comprising one or more algorithms for calculating the suspension ratio of air pressure between the one or more tag suspensions and the drive suspension, determining a driving condition based on ride height inputs and comparing the calculated suspension ratio against a predetermined suspension ratio of air pressure for said driving condition, said processor being in communication to open or close said one or more valves to adjust air pressure in any one or more of said one or more air springs to set the suspension ratio of air pressure to the predetermined suspension ratio of air pressure.
A method is further provided for configuring suspension ratios in a multi-rear axle vehicle, said vehicle having a drive axle suspension and at least one tag axle suspension, each suspension comprising one or more air springs. The method comprises the steps of:
a) providing the system described above;
b) taking pressure measurements from the one or more manifold lines;
3 Date Recue/Date Received 2020-07-29 C) monitoring ride height of the vehicle; and d) sending pressure measurements and ride height inputs to a processor, said processor performing the steps of:
i. calculating the suspension ratio of air pressure between the one or more tag suspensions and the drive suspension, ii. determining a driving condition based on ride height inputs;
iii. comparing the calculated suspension ratio against a predetermined suspension ratio of air pressure for said driving condition; and iv. controlling said one or more valves to open or close said to adjust air pressure in any one or more of said one or more air springs to set the suspension ratio of air pressure to the predetermined suspension ratio of air pressure.
A system is further provided for determining and averaging fluctuations in suspension height or air spring pressure readings of one or more air spring suspensions in a multi-rear axle vehicle and for adjusting said suspension height and air spring pressure readings. The system comprises:
a. one or more sensors for determining acceleration data of the vehicle;
b. one or more timers for determining a time interval since a previous adjustment of said suspension height or air spring pressure; and c. a processor receiving signals containing suspension heights, air spring pressure readings, acceleration data and time interval data and comprising one or more algorithms for determining if a maximum time interval has passed since the previous adjustment; determining if a normal time interval has passed since the previous adjustment, if the maximum time interval has not passed; taking a further vehicle acceleration measurement if the normal time interval has also not been reached, or if a normal time interval has been reached but acceleration is
i. calculating the suspension ratio of air pressure between the one or more tag suspensions and the drive suspension, ii. determining a driving condition based on ride height inputs;
iii. comparing the calculated suspension ratio against a predetermined suspension ratio of air pressure for said driving condition; and iv. controlling said one or more valves to open or close said to adjust air pressure in any one or more of said one or more air springs to set the suspension ratio of air pressure to the predetermined suspension ratio of air pressure.
A system is further provided for determining and averaging fluctuations in suspension height or air spring pressure readings of one or more air spring suspensions in a multi-rear axle vehicle and for adjusting said suspension height and air spring pressure readings. The system comprises:
a. one or more sensors for determining acceleration data of the vehicle;
b. one or more timers for determining a time interval since a previous adjustment of said suspension height or air spring pressure; and c. a processor receiving signals containing suspension heights, air spring pressure readings, acceleration data and time interval data and comprising one or more algorithms for determining if a maximum time interval has passed since the previous adjustment; determining if a normal time interval has passed since the previous adjustment, if the maximum time interval has not passed; taking a further vehicle acceleration measurement if the normal time interval has also not been reached, or if a normal time interval has been reached but acceleration is
4 Date Recue/Date Received 2020-07-29 not below a predetermined threshold value; if the maximum time interval has been reached; or if the normal time interval has been reached and acceleration is below the predetermined threshold, then performing an adjustment cycle series of steps as follows:
i. determining suspension height or air spring pressures;
ii. assessing suspension height or air spring pressures using predetermined criteria to determine if the suspension heights or air spring pressures require adjustment;
iii. calculating a scaled adjustment of the suspension heights or air spring pressures, based on vehicle acceleration;
iv. adjusting suspension heights or air spring pressures using scaled adjustment.
A further method is provided for averaging fluctuations in suspension height or air pressure readings of one or more air spring suspensions in a multi-rear axle vehicle and for performing an adjustment cycle series of steps for adjusting said suspension height and air spring pressure readings. The method comprises:
a. determining acceleration of the vehicle;
b. determining if a maximum time interval has passed since a previous adjustment cycle series of steps was run;
c. determining if a normal time interval has passed since the previous adjustment cycle series of steps, if the maximum time interval has not passed;
d. taking a further vehicle acceleration measurement if the normal time interval has also not been reached, or if a normal time interval has been reached but acceleration is not below a predetermined threshold value; and e. if the maximum time interval has been reached; or if the normal time interval has been reached and acceleration is below the predetermined threshold, then performing the adjustment cycle series of steps as follows:
i. determining suspension height or air spring pressures;
ii. assessing suspension height or air spring pressures using predetermined criteria to determine if the suspension heights or air spring pressures require adjustment;
iii. calculating a scaled adjustment of the suspension heights or air spring pressures, based on vehicle acceleration;
iv. adjusting suspension heights or air spring pressures using scaled adjustment.
A further method is provided for averaging fluctuations in suspension height or air pressure readings of one or more air spring suspensions in a multi-rear axle vehicle and for performing an adjustment cycle series of steps for adjusting said suspension height and air spring pressure readings. The method comprises:
a. determining acceleration of the vehicle;
b. determining if a maximum time interval has passed since a previous adjustment cycle series of steps was run;
c. determining if a normal time interval has passed since the previous adjustment cycle series of steps, if the maximum time interval has not passed;
d. taking a further vehicle acceleration measurement if the normal time interval has also not been reached, or if a normal time interval has been reached but acceleration is not below a predetermined threshold value; and e. if the maximum time interval has been reached; or if the normal time interval has been reached and acceleration is below the predetermined threshold, then performing the adjustment cycle series of steps as follows:
5 Date Recue/Date Received 2020-07-29 i. determining suspension height or air spring pressures;
ii. assessing suspension height or air spring pressures using predetermined criteria to determine if the suspension heights or air spring pressures require adjustment;
iii. calculating a scaled adjustment of the suspension heights or air spring pressures, based on vehicle acceleration;
iv. adjusting suspension heights or air spring pressures using scaled adjustment; and v. repeating steps a. to e.
Finally, a method is provided for configuring suspension ratios in a multi-rear axle vehicle, said vehicle having a drive axle suspension and at least one tag axle suspension, and for adjusting said air suspension pressures. The method comprises:
a) taking air suspension pressure readings;
b) determining acceleration data of the vehicle;
c) performing an adjustment cycle series of steps as follows:
i. assessing air suspension pressures using predetermined criteria to determine if the air spring pressures require adjustment;
ii. calculating a scaled adjustment of the air suspension pressures, based on vehicle acceleration; and iv. adjusting air suspension pressures using scaled adjustment;
d) monitoring ride height of the vehicle; and e) sending adjusted air suspension pressure measurements and ride height inputs to a processor, said processor performing the steps of:
i. calculating the suspension ratio of adjusted air suspension pressures between the one or more tag suspensions and the drive suspension, ii. determining a driving condition based on ride height inputs;
ii. assessing suspension height or air spring pressures using predetermined criteria to determine if the suspension heights or air spring pressures require adjustment;
iii. calculating a scaled adjustment of the suspension heights or air spring pressures, based on vehicle acceleration;
iv. adjusting suspension heights or air spring pressures using scaled adjustment; and v. repeating steps a. to e.
Finally, a method is provided for configuring suspension ratios in a multi-rear axle vehicle, said vehicle having a drive axle suspension and at least one tag axle suspension, and for adjusting said air suspension pressures. The method comprises:
a) taking air suspension pressure readings;
b) determining acceleration data of the vehicle;
c) performing an adjustment cycle series of steps as follows:
i. assessing air suspension pressures using predetermined criteria to determine if the air spring pressures require adjustment;
ii. calculating a scaled adjustment of the air suspension pressures, based on vehicle acceleration; and iv. adjusting air suspension pressures using scaled adjustment;
d) monitoring ride height of the vehicle; and e) sending adjusted air suspension pressure measurements and ride height inputs to a processor, said processor performing the steps of:
i. calculating the suspension ratio of adjusted air suspension pressures between the one or more tag suspensions and the drive suspension, ii. determining a driving condition based on ride height inputs;
6 Date Recue/Date Received 2020-07-29 iii. comparing the calculated suspension ratio against a predetermined suspension ratio of air pressure for said driving condition; and iv. adjusting air pressure in any one or more of said one or more air suspensions to set the suspension ratio of air pressure to the predetermined suspension ratio of air pressure.
It is to be understood that other aspects of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the disclosure are shown and described by way of illustration.
As will be realized, the disclosure is capable of other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present disclosure. Accordingly the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
.. A further, detailed, description of the disclosure, briefly described above, will follow by reference to the following drawings of specific embodiments of the disclosure.
The drawings depict only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope. In the drawings:
Figure 1 is schematic diagram of a first example of a system of the present disclosure, having a single rear manifold and a single pressure transducer;
Figure 2 is schematic diagram of a second example of a system of the present disclosure, having a single rear manifold and four rear pressure transducers;
Figure 3 is a schematic diagram of a third example of a system of the present disclosure having a dual rear manifold, each manifold with a pressure transducer; and Figure 4 is a schematic diagram of a fourth example of a system of the present disclosure, having a dual rear manifold and four rear pressure transducers;
and
It is to be understood that other aspects of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the disclosure are shown and described by way of illustration.
As will be realized, the disclosure is capable of other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present disclosure. Accordingly the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
.. A further, detailed, description of the disclosure, briefly described above, will follow by reference to the following drawings of specific embodiments of the disclosure.
The drawings depict only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope. In the drawings:
Figure 1 is schematic diagram of a first example of a system of the present disclosure, having a single rear manifold and a single pressure transducer;
Figure 2 is schematic diagram of a second example of a system of the present disclosure, having a single rear manifold and four rear pressure transducers;
Figure 3 is a schematic diagram of a third example of a system of the present disclosure having a dual rear manifold, each manifold with a pressure transducer; and Figure 4 is a schematic diagram of a fourth example of a system of the present disclosure, having a dual rear manifold and four rear pressure transducers;
and
7 Date Recue/Date Received 2020-07-29 Figure 5 is a logic flow diagram illustrating one example of a method of the present disclosure.
The drawings are not necessarily to scale and in some instances proportions may have been exaggerated in order to more clearly depict certain features.
DETAILED DESCRIPTION
The description that follows and the embodiments described therein are provided by way of illustration of an example, or examples, of particular embodiments of the principles of various aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure in its various aspects.
The present disclosure provides a system for electronically maintaining configurable ratios between air spring pressures in various axles of a multiple rear axle vehicle, to allow for optimization of load distribution, balance and control. It is particularly related to vehicles carrying large loads or towing trailers behind the vehicle.
The present invention also provides a system and method for averaging or adjusting for fluctuations in the pressure readings taken on the air springs, while the vehicle is in motion. The system utilizes measurements of the vehicle's acceleration, speed and ride height, and performs calculations to determine whether there is a high confidence level in the pressure readings. The present system can make changes to the pressurization of the air springs so as to maintain a particular air suspension pressure ratio between the tag and drive axles once it is determined that there is a high confidence level in the pressure readings.
It is not uncommon in such vehicles for the load bearing tag axles to reach suspension capacity before other axles. In such cases, it is important to reduce pressure in the tag axle suspension and also to reach an optimal proportion of air pressure between axle suspensions. This is particularly true between the drive axle and the one or more rear tag axles.
The drawings are not necessarily to scale and in some instances proportions may have been exaggerated in order to more clearly depict certain features.
DETAILED DESCRIPTION
The description that follows and the embodiments described therein are provided by way of illustration of an example, or examples, of particular embodiments of the principles of various aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure in its various aspects.
The present disclosure provides a system for electronically maintaining configurable ratios between air spring pressures in various axles of a multiple rear axle vehicle, to allow for optimization of load distribution, balance and control. It is particularly related to vehicles carrying large loads or towing trailers behind the vehicle.
The present invention also provides a system and method for averaging or adjusting for fluctuations in the pressure readings taken on the air springs, while the vehicle is in motion. The system utilizes measurements of the vehicle's acceleration, speed and ride height, and performs calculations to determine whether there is a high confidence level in the pressure readings. The present system can make changes to the pressurization of the air springs so as to maintain a particular air suspension pressure ratio between the tag and drive axles once it is determined that there is a high confidence level in the pressure readings.
It is not uncommon in such vehicles for the load bearing tag axles to reach suspension capacity before other axles. In such cases, it is important to reduce pressure in the tag axle suspension and also to reach an optimal proportion of air pressure between axle suspensions. This is particularly true between the drive axle and the one or more rear tag axles.
8 Date Recue/Date Received 2020-07-29 With reference to the Figures, the present system 2 includes a manifold assembly 4, said manifold assembly 4 having at least one inlet line 6 connected to a compressed air supply source 8. The manifold assembly includes at least one manifold line 10 to supply compressed air to the air springs 12a/b, 14a/b of an air suspension system of each of the tag axle 12 and drive axles 14. In the figures a single curb 14a and street 14b drive axle and single curb 12a and street 12b tag axle are shown although it would be understood by a person of skill in the art that multiple tag axles may be present. The manifold assembly also includes an exhaust line 16 for exhausting any of the air springs of any tag or drive suspensions. Manual fill lines (not shown) may also be included on .. all axle suspensions.
Valves 30 are provided on the manifold lines 10 between each of the air springs 12a/b, 14a/b and the inlet line 6 and valves 32 are provided between the air springs 12a/b and 14a/b and the exhaust line 16. Valves 30/32 are controlled by the system of the present disclosure to allow for pressurizing or depressurizing of each of air springs as needed.
Figure 1 illustrates a system in which a single rear pressure transducer 20 is connected to the manifold. Figure 2 illustrates a system having a separate rear pressure transducers 20a, 20b, 20c, 20d connected to each of the air springs. Figure 3 illustrates a system in which the manifold includes two parallel manifold lines 10a/10b, one for each of the tag and the drive axles, and a dedicated pressure transducer 20a/20b for each manifold line 10a/10b. Figure 4 illustrates a system in which the manifold includes two parallel manifold lines 10a/10b having a separate rear pressure transducer 20a, 20b, 20c, 20d connected to each of the air springs.
With reference to the Figures, the steering axle and associated suspensions 22 may also be air spring suspensions and may optionally also be connected to the same .. compressed air source 8 by its own valve assembly 24, including an exhaust 26. The steering axle suspension may also include a pressure transducer of its own (not shown).
The system monitors air spring pressures in each of the drive and tag axles.
While using a single pressure transducer can be desirable due to lower cost and less maintenance, the frequent pressure measurements required to achieve accuracy leads
Valves 30 are provided on the manifold lines 10 between each of the air springs 12a/b, 14a/b and the inlet line 6 and valves 32 are provided between the air springs 12a/b and 14a/b and the exhaust line 16. Valves 30/32 are controlled by the system of the present disclosure to allow for pressurizing or depressurizing of each of air springs as needed.
Figure 1 illustrates a system in which a single rear pressure transducer 20 is connected to the manifold. Figure 2 illustrates a system having a separate rear pressure transducers 20a, 20b, 20c, 20d connected to each of the air springs. Figure 3 illustrates a system in which the manifold includes two parallel manifold lines 10a/10b, one for each of the tag and the drive axles, and a dedicated pressure transducer 20a/20b for each manifold line 10a/10b. Figure 4 illustrates a system in which the manifold includes two parallel manifold lines 10a/10b having a separate rear pressure transducer 20a, 20b, 20c, 20d connected to each of the air springs.
With reference to the Figures, the steering axle and associated suspensions 22 may also be air spring suspensions and may optionally also be connected to the same .. compressed air source 8 by its own valve assembly 24, including an exhaust 26. The steering axle suspension may also include a pressure transducer of its own (not shown).
The system monitors air spring pressures in each of the drive and tag axles.
While using a single pressure transducer can be desirable due to lower cost and less maintenance, the frequent pressure measurements required to achieve accuracy leads
9 Date Recue/Date Received 2020-07-29 to increased valve wear due to repeated opening and closing of valves to isolate a particular air spring for pressure measurement.
In the present system and methods, means are provided, described in further detail below, for optimizing pressure readings with acceleration data, so that even in a single pressure transducer embodiment more reliable data is achieved without increasing the reading frequency. This in turn reduces valve wear.
In the arrangement of Figures 2 and 4, multiple pressure transducers, it is possible to read pressures in each of the drive and tag suspensions at the same time, which also leads to a tag to drive suspension ratio that is more reflective of current conditions. The system can then be programmed to meet a desired ratio of air suspension pressures.
The present system and method provides a set of threshold ratios of drive suspension pressure to tag suspension pressure which allow for optimal performance of the vehicle in various conditions. The present system is in contrast to prior systems which measure and adjust drive and tag suspension pressures in unison with a desired value overall for these suspensions. In the present disclosure it is a ratio between the tag and drive suspensions that the inventors have found to improve load bearing and balancing performance of the vehicle.
The system can be programmed with multiple configured ratios of drive/tag air suspension pressure that can be selected based on vehicle operating condition such as towing a trailer or changing the weight distribution of loaded cargo. The goal is to maintain vehicle ride height and a balanced weight across the vehicle.
Conditions for setting desired ratios can depend on the configuration of the vehicle chassis or frame, loading of the vehicle, if it is towing and what it is towing, and driving conditions, among others.
One or more accelerometers provide acceleration state information such as an indication of whether the vehicle is accelerating, decelerating, stopped or turning.
Sensor data and air pressure sampling can be taken at the start of a driving, and then throughout the driving at a variety of intervals. Initially the sampling and reading intervals are more frequent, and more preferably between every 2-5 minutes.
Once an Date Recue/Date Received 2020-07-29 optimal ratio of tag to drive air suspension pressures is achieved, then sample reading rate is preferably reduced.
Further measurements and inputs into algorithms of the present system allow for air pressure adjustments to be then made to enable the system to maintain the selected ratio. For example, the system can include one or more height sensors to provide ride height information for each axle, and said height information can also be provided input into the algorithms to determine how much air should be added to or removed from any particular air spring of a particular axle suspension to maintain the desired ratio of suspensions.
The present system and algorithms provide a proportional ratio of axle suspension pressures that allows for pressure in any of the drive or tag suspensions to be adjusted to meet that ratio, rather than adjusting all tag and drive suspensions together. Since the present system is tag suspension-to-drive suspension ratio driven, individual pressures are less important that the overall pressure ratio.
In the single rear pressure transducer embodiment of the present invention, as mentioned earlier, driving data is used to optimize the pressure readings, leading to more reliable pressure data without the need for frequent pressure reading.
For example, it may be found that pressure readings with a more accurate confidence factor can be taken if accelerations are read before, during and after the pressures are read. In this example, taking acceleration readings before, during and after the pressure readings would provide additional confidence in the accuracy of the pressure readings, and could be used to make the scaled adjustments more accurate when adjusting the tag suspension-to-drive suspension ratio.
In a single pressure transducer system, the pressure in the air springs must be read .. sequentially, so the present algorithms can be used to improve on the accuracy of the readings and average out fluctuations due to changes in driving conditions between the first axle pressure reading to the last.
In a preferred embodiment, fluctuations in air pressure and suspension height data can also be smoothed out or adjusted by algorithms of the present system, together with Date Recue/Date Received 2020-07-29 further data measurements and more specifically acceleration and speed, to adjust the air pressure and suspension height data from the air springs to be relied upon.
The present system and associated algorithms function while the vehicle is stationary and in motion. When a vehicle is in motion the air spring pressures fluctuate depending on driving and road conditions. To ensure accurate air pressure measurements the system monitors such parameters as the vehicle's acceleration state and speed to establish a confidence level for whether the air pressure and suspension height measurements are accurate or not and whether an adjustment is needed for the pressure reading. The present system allows suspension air pressure and ride height, which is a factor of suspension pressure, to be controlled with only one pressure transducer.
Figure 5 illustrates one example of a set of decisions performed by the algorithms of the present invention. The steps of Figure 5 can be subdivided into an acceleration reading cycle and an adjustment cycle. In this example, both a normal and maximum interval of time are set for reading and adjusting suspension height and air spring pressures in the adjustment cycle. With reference to this example, firstly acceleration of the vehicle is determined. Secondly a determination is made of whether the maximum adjustment time interval has passed since the algorithm last ran the adjustment cycle of steps. If the maximum time interval has been reached then, regardless of the acceleration reading, an adjustment cycle is performed, as described below.
If the maximum adjustment time interval has not passed, then a determination is made of whether the normal adjustment time interval has been reached.
If the normal adjustment interval has also not been reached, or if a normal adjustment interval has been reached but acceleration is not below a predetermined threshold value, then another acceleration measurement is taken and the acceleration reading cycle is repeated.
If the maximum adjustment time interval has been reached; or if the normal adjustment interval has been reached and acceleration is below the predetermined threshold, then the system performs the adjustment cycle series of steps as follows:
Date Recue/Date Received 2020-07-29 a. the suspension height and/or air spring pressures are measured;
b. the suspension height and/or air spring pressure readings are compared to a target value and corresponding tolerance to determine if the suspension heights and/or air spring pressures require adjustment;
.. c. a scaled adjustment of the suspension heights and/or air spring pressures is calculated, based on vehicle speed and acceleration; and d. suspension heights and/or air spring pressures are adjusted accordingly.
Once suspension height and air spring pressures are adjusted, or should no adjustment be required, then a new adjustment interval time is started and another vehicle acceleration reading is taken to start a new acceleration reading cycle.
No adjustment is required if the suspension height and air spring pressures are within the target value and corresponding tolerance.
For example, a target ride height of 0" with a tolerance of +/-0.1" and air spring pressure 65p5i with a tolerance of +/-1psi is defined as a state in which the suspension is at normal driving height and air pressure. An adjustment would be required if the suspension height is found to be above 0.1" or below -0.1" and/or if an air spring pressure is found to be higher 66p5i or lower than 64p5i.
In one example acceleration data is used to set a confidence factor associated with the suspension height and/or air spring pressure. Acceleration of the vehicle is typically .. measured in a number of different planes: lateral acceleration refers to forces on a vehicle that are orthogonal to the direction of travel, often felt in turning;
longitudinal acceleration relates to forces along the direction of travel, often felt during climbing up or descending down an incline; vertical acceleration relating to bumps or up and down forces felt by the vehicle, for example when travelling on straight roads that have dips .. and humps that cause the two ends of the vehicle to oscillate up and down, opposite each other. Additionally acceleration or deceleration of the vehicle as it speeds up or slows down are also taken into account.
Date Recue/Date Received 2020-07-29 In one example, the confidence factor can initially be set to 1.0, correlating to a full confidence in suspension height and/or air spring pressure readings. Depending on vehicle acceleration, the confidence factor can be adjusted as follows in this Example:
= If the change in lateral acceleration is higher than 1.5 mg/ms the confidence factor is decreased by 10% to 0.9;
= If the change in longitudinal acceleration is higher than 1 mg/ms the confidence factor is decreased by 20% to 0.8;
= If the change in vertical acceleration is greater than 1 mg/ms the confidence factor is decreased by 20% to 0.8;
= If the vehicle speed is accelerating or decelerating 6 km/h/s the confidence factor is decreased by 40% to 0.6;
= If the vehicle speed is accelerating or decelerating 2 km/h/s the confidence factor is decreased by 20% to 0.8;
The above system of adjusting and establishing a confidence level in suspension height and air pressure data can also be applied to the system and methods of using a ratio between the tag and drive suspensions that was discussed earlier. Since an incorrect drive or tag air pressure reading can lead to an inaccurate drive- to-tag suspension ratio, it is important to limit the amount of drive and tag air pressure adjustments that are made when there is a lower confidence level in the pressure data, to in turn achieve a .. more accurate drive-to-tag ratio.
The present inventors note that both braking and vehicle acceleration have a large impact on suspension air pressures.
By contrast, the present inventors have surprisingly found that cornering (that is, lateral acceleration forces) and driving on rough roads (that is, quick and low amplitude vertical acceleration forces) have little effect on the air spring pressures when comparing the drive and tag axle suspension pressures on a given side of the vehicle.
The inventors have further found that travelling on straight roads that have dips and humps (slower or higher amplitude vertical acceleration) has a larger effect on suspension air pressure when comparing the drive and tag axle on a given side of the vehicle.
Date Recue/Date Received 2020-07-29 The system also provides ability to measure weight of the vehicle. Sprung weight of a vehicle can be estimated based on air spring pressures, ride height measurements and use of manufacturer air spring design charts. This weight data is also used in the algorithms to determine existing air suspension pressure ratios and to correct for said .. ratios.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the claims, wherein reference to an element in the singular, such as by use of the article "a" or "an" is not intended to mean "one and only one" unless specifically so stated, but rather "one or more". All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the elements of the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.
Date Recue/Date Received 2020-07-29
In the present system and methods, means are provided, described in further detail below, for optimizing pressure readings with acceleration data, so that even in a single pressure transducer embodiment more reliable data is achieved without increasing the reading frequency. This in turn reduces valve wear.
In the arrangement of Figures 2 and 4, multiple pressure transducers, it is possible to read pressures in each of the drive and tag suspensions at the same time, which also leads to a tag to drive suspension ratio that is more reflective of current conditions. The system can then be programmed to meet a desired ratio of air suspension pressures.
The present system and method provides a set of threshold ratios of drive suspension pressure to tag suspension pressure which allow for optimal performance of the vehicle in various conditions. The present system is in contrast to prior systems which measure and adjust drive and tag suspension pressures in unison with a desired value overall for these suspensions. In the present disclosure it is a ratio between the tag and drive suspensions that the inventors have found to improve load bearing and balancing performance of the vehicle.
The system can be programmed with multiple configured ratios of drive/tag air suspension pressure that can be selected based on vehicle operating condition such as towing a trailer or changing the weight distribution of loaded cargo. The goal is to maintain vehicle ride height and a balanced weight across the vehicle.
Conditions for setting desired ratios can depend on the configuration of the vehicle chassis or frame, loading of the vehicle, if it is towing and what it is towing, and driving conditions, among others.
One or more accelerometers provide acceleration state information such as an indication of whether the vehicle is accelerating, decelerating, stopped or turning.
Sensor data and air pressure sampling can be taken at the start of a driving, and then throughout the driving at a variety of intervals. Initially the sampling and reading intervals are more frequent, and more preferably between every 2-5 minutes.
Once an Date Recue/Date Received 2020-07-29 optimal ratio of tag to drive air suspension pressures is achieved, then sample reading rate is preferably reduced.
Further measurements and inputs into algorithms of the present system allow for air pressure adjustments to be then made to enable the system to maintain the selected ratio. For example, the system can include one or more height sensors to provide ride height information for each axle, and said height information can also be provided input into the algorithms to determine how much air should be added to or removed from any particular air spring of a particular axle suspension to maintain the desired ratio of suspensions.
The present system and algorithms provide a proportional ratio of axle suspension pressures that allows for pressure in any of the drive or tag suspensions to be adjusted to meet that ratio, rather than adjusting all tag and drive suspensions together. Since the present system is tag suspension-to-drive suspension ratio driven, individual pressures are less important that the overall pressure ratio.
In the single rear pressure transducer embodiment of the present invention, as mentioned earlier, driving data is used to optimize the pressure readings, leading to more reliable pressure data without the need for frequent pressure reading.
For example, it may be found that pressure readings with a more accurate confidence factor can be taken if accelerations are read before, during and after the pressures are read. In this example, taking acceleration readings before, during and after the pressure readings would provide additional confidence in the accuracy of the pressure readings, and could be used to make the scaled adjustments more accurate when adjusting the tag suspension-to-drive suspension ratio.
In a single pressure transducer system, the pressure in the air springs must be read .. sequentially, so the present algorithms can be used to improve on the accuracy of the readings and average out fluctuations due to changes in driving conditions between the first axle pressure reading to the last.
In a preferred embodiment, fluctuations in air pressure and suspension height data can also be smoothed out or adjusted by algorithms of the present system, together with Date Recue/Date Received 2020-07-29 further data measurements and more specifically acceleration and speed, to adjust the air pressure and suspension height data from the air springs to be relied upon.
The present system and associated algorithms function while the vehicle is stationary and in motion. When a vehicle is in motion the air spring pressures fluctuate depending on driving and road conditions. To ensure accurate air pressure measurements the system monitors such parameters as the vehicle's acceleration state and speed to establish a confidence level for whether the air pressure and suspension height measurements are accurate or not and whether an adjustment is needed for the pressure reading. The present system allows suspension air pressure and ride height, which is a factor of suspension pressure, to be controlled with only one pressure transducer.
Figure 5 illustrates one example of a set of decisions performed by the algorithms of the present invention. The steps of Figure 5 can be subdivided into an acceleration reading cycle and an adjustment cycle. In this example, both a normal and maximum interval of time are set for reading and adjusting suspension height and air spring pressures in the adjustment cycle. With reference to this example, firstly acceleration of the vehicle is determined. Secondly a determination is made of whether the maximum adjustment time interval has passed since the algorithm last ran the adjustment cycle of steps. If the maximum time interval has been reached then, regardless of the acceleration reading, an adjustment cycle is performed, as described below.
If the maximum adjustment time interval has not passed, then a determination is made of whether the normal adjustment time interval has been reached.
If the normal adjustment interval has also not been reached, or if a normal adjustment interval has been reached but acceleration is not below a predetermined threshold value, then another acceleration measurement is taken and the acceleration reading cycle is repeated.
If the maximum adjustment time interval has been reached; or if the normal adjustment interval has been reached and acceleration is below the predetermined threshold, then the system performs the adjustment cycle series of steps as follows:
Date Recue/Date Received 2020-07-29 a. the suspension height and/or air spring pressures are measured;
b. the suspension height and/or air spring pressure readings are compared to a target value and corresponding tolerance to determine if the suspension heights and/or air spring pressures require adjustment;
.. c. a scaled adjustment of the suspension heights and/or air spring pressures is calculated, based on vehicle speed and acceleration; and d. suspension heights and/or air spring pressures are adjusted accordingly.
Once suspension height and air spring pressures are adjusted, or should no adjustment be required, then a new adjustment interval time is started and another vehicle acceleration reading is taken to start a new acceleration reading cycle.
No adjustment is required if the suspension height and air spring pressures are within the target value and corresponding tolerance.
For example, a target ride height of 0" with a tolerance of +/-0.1" and air spring pressure 65p5i with a tolerance of +/-1psi is defined as a state in which the suspension is at normal driving height and air pressure. An adjustment would be required if the suspension height is found to be above 0.1" or below -0.1" and/or if an air spring pressure is found to be higher 66p5i or lower than 64p5i.
In one example acceleration data is used to set a confidence factor associated with the suspension height and/or air spring pressure. Acceleration of the vehicle is typically .. measured in a number of different planes: lateral acceleration refers to forces on a vehicle that are orthogonal to the direction of travel, often felt in turning;
longitudinal acceleration relates to forces along the direction of travel, often felt during climbing up or descending down an incline; vertical acceleration relating to bumps or up and down forces felt by the vehicle, for example when travelling on straight roads that have dips .. and humps that cause the two ends of the vehicle to oscillate up and down, opposite each other. Additionally acceleration or deceleration of the vehicle as it speeds up or slows down are also taken into account.
Date Recue/Date Received 2020-07-29 In one example, the confidence factor can initially be set to 1.0, correlating to a full confidence in suspension height and/or air spring pressure readings. Depending on vehicle acceleration, the confidence factor can be adjusted as follows in this Example:
= If the change in lateral acceleration is higher than 1.5 mg/ms the confidence factor is decreased by 10% to 0.9;
= If the change in longitudinal acceleration is higher than 1 mg/ms the confidence factor is decreased by 20% to 0.8;
= If the change in vertical acceleration is greater than 1 mg/ms the confidence factor is decreased by 20% to 0.8;
= If the vehicle speed is accelerating or decelerating 6 km/h/s the confidence factor is decreased by 40% to 0.6;
= If the vehicle speed is accelerating or decelerating 2 km/h/s the confidence factor is decreased by 20% to 0.8;
The above system of adjusting and establishing a confidence level in suspension height and air pressure data can also be applied to the system and methods of using a ratio between the tag and drive suspensions that was discussed earlier. Since an incorrect drive or tag air pressure reading can lead to an inaccurate drive- to-tag suspension ratio, it is important to limit the amount of drive and tag air pressure adjustments that are made when there is a lower confidence level in the pressure data, to in turn achieve a .. more accurate drive-to-tag ratio.
The present inventors note that both braking and vehicle acceleration have a large impact on suspension air pressures.
By contrast, the present inventors have surprisingly found that cornering (that is, lateral acceleration forces) and driving on rough roads (that is, quick and low amplitude vertical acceleration forces) have little effect on the air spring pressures when comparing the drive and tag axle suspension pressures on a given side of the vehicle.
The inventors have further found that travelling on straight roads that have dips and humps (slower or higher amplitude vertical acceleration) has a larger effect on suspension air pressure when comparing the drive and tag axle on a given side of the vehicle.
Date Recue/Date Received 2020-07-29 The system also provides ability to measure weight of the vehicle. Sprung weight of a vehicle can be estimated based on air spring pressures, ride height measurements and use of manufacturer air spring design charts. This weight data is also used in the algorithms to determine existing air suspension pressure ratios and to correct for said .. ratios.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the claims, wherein reference to an element in the singular, such as by use of the article "a" or "an" is not intended to mean "one and only one" unless specifically so stated, but rather "one or more". All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the elements of the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.
Date Recue/Date Received 2020-07-29
Claims (17)
1. A system for configuring suspension ratios in a multi-rear axle vehicle, said vehicle having a drive axle suspension and at least one tag axle suspension, each suspension comprising one or more air springs, the system comprising:
a. a manifold comprising one or more manifold lines for supplying compressed air to or exhausting air from the one or more air springs of the drive axle suspension and tag axle suspensions;
b. at least one supply valve on the manifold lines between each air spring and the supply of compressed air c. at least one exhaust valve on the manifold lines between each air spring and the exhaust;
d. at least one pressure transducer for taking pressure measurements from the one or more manifold lines;
e. one or more ride height sensors for monitoring ride height of the vehicle;
and f. a processor receiving signals containing pressure measurements from the at least one pressure transducer and ride height inputs from the ride height sensors, and comprising one or more algorithms for calculating the suspension ratio of air pressure between the one or more tag suspensions and the drive suspension, determining a driving condition based on ride height inputs and comparing the calculated suspension ratio against a predetermined suspension ratio of air pressure for said driving condition, said processor being in communication to open or close said one or more valves to adjust air pressure in any one or more of said one or more air springs to set the suspension ratio of air pressure to the predetermined suspension ratio of air pressure.
a. a manifold comprising one or more manifold lines for supplying compressed air to or exhausting air from the one or more air springs of the drive axle suspension and tag axle suspensions;
b. at least one supply valve on the manifold lines between each air spring and the supply of compressed air c. at least one exhaust valve on the manifold lines between each air spring and the exhaust;
d. at least one pressure transducer for taking pressure measurements from the one or more manifold lines;
e. one or more ride height sensors for monitoring ride height of the vehicle;
and f. a processor receiving signals containing pressure measurements from the at least one pressure transducer and ride height inputs from the ride height sensors, and comprising one or more algorithms for calculating the suspension ratio of air pressure between the one or more tag suspensions and the drive suspension, determining a driving condition based on ride height inputs and comparing the calculated suspension ratio against a predetermined suspension ratio of air pressure for said driving condition, said processor being in communication to open or close said one or more valves to adjust air pressure in any one or more of said one or more air springs to set the suspension ratio of air pressure to the predetermined suspension ratio of air pressure.
2. The system of claim 1, wherein the processor further receives vehicle acceleration data and wherein the one or more algorithms of the processor are used for adjusting the pressure measurements based on the acceleration data.
Date Recue/Date Received 2020-07-29
Date Recue/Date Received 2020-07-29
3. The system of claim 1, wherein the predetermined suspension ratio is determined based on factors selected from the group consisting of chassis configuration, towing status, towing load, vehicle loading, driving conditions and combinations thereof.
4. The system of claim 1, wherein the manifold comprises two parallel manifold lines, one for each of the tag axle suspension and the drive axle suspension, and having a separate rear pressure transducer connected to each of the parallel manifold lines.
5. The system of claim 1, wherein the system comprises a dedicated pressure transducer connected with each air spring of each axle suspension.
6. The system of claim 1, wherein the driving conditions are real-time driving conditions.
7. A method for configuring suspension ratios in a multi-rear axle vehicle, said vehicle having a drive axle suspension and at least one tag axle suspension, each suspension comprising one or more air springs, the method comprising the steps of:
a) providing the system according to claim 1;
b) taking pressure measurements from the one or more manifold lines;
c) monitoring ride height of the vehicle; and d) sending pressure measurements and ride height inputs to a processor, said processor performing the steps of:
i.
calculating the suspension ratio of air pressure between the one or more tag suspensions and the drive suspension, ii. determining a driving condition based on ride height inputs;
iii. comparing the calculated suspension ratio against a predetermined suspension ratio of air pressure for said driving condition; and iv. controlling said one or more valves to open or close said to adjust air pressure in any one or more of said one or more air springs to set the Date Recue/Date Received 2020-07-29 suspension ratio of air pressure to the predetermined suspension ratio of air pressure.
a) providing the system according to claim 1;
b) taking pressure measurements from the one or more manifold lines;
c) monitoring ride height of the vehicle; and d) sending pressure measurements and ride height inputs to a processor, said processor performing the steps of:
i.
calculating the suspension ratio of air pressure between the one or more tag suspensions and the drive suspension, ii. determining a driving condition based on ride height inputs;
iii. comparing the calculated suspension ratio against a predetermined suspension ratio of air pressure for said driving condition; and iv. controlling said one or more valves to open or close said to adjust air pressure in any one or more of said one or more air springs to set the Date Recue/Date Received 2020-07-29 suspension ratio of air pressure to the predetermined suspension ratio of air pressure.
8. The method of claim 7 further comprising the step of:
b) i. determining acceleration data of the vehicle; and b) ii. adjusting pressure measurements using the acceleration data.
b) i. determining acceleration data of the vehicle; and b) ii. adjusting pressure measurements using the acceleration data.
9. The method of claim 7, wherein pressure measurements are taken at the start of driving, and subsequently at predetermined intervals during driving.
10. The method of claim 9, wherein the predetermined intervals are more frequent near the start of driving and less frequent once the predetermined suspension ratio of air pressure is reached.
11. The method of claim 10, wherein the predetermined intervals near the start of driving are between every 15 to 60 seconds
12. The method of claim 10, wherein the predetermined intervals once the predetermined suspension ratio of air pressure is reached are between every 2-m inutes.
13. A system for determining and averaging fluctuations in suspension height or air spring pressure readings of one or more air spring suspensions in a multi-rear axle vehicle and for adjusting said suspension height and air spring pressure readings; the system comprising:
a. one or more sensors for determining acceleration data of the vehicle;
b. one or more timers for determining a time interval since a previous adjustment of said suspension height or air spring pressure; and c. a processor receiving suspension heights, air spring pressure readings, acceleration data and time interval data and comprising one or more algorithms for determining if a maximum time interval has passed since the previous adjustment; determining if a normal time interval has passed since the previous adjustment, if the maximum time interval has not passed; taking a further vehicle Date Recue/Date Received 2020-07-29 acceleration measurement if the normal time interval has also not been reached, or if a normal time interval has been reached but acceleration is not below a predetermined threshold value; if the maximum time interval has been reached;
or if the normal time interval has been reached and acceleration is below the predetermined threshold, then performing an adjustment cycle series of steps as follows:
i. determining suspension height or air spring pressures;
ii. assessing suspension height or air spring pressures using predetermined criteria to determine if the suspension heights or air spring pressures require adjustment;
iii. calculating a scaled adjustment of the suspension heights or air spring pressures, based on vehicle acceleration;
iv. adjusting suspension heights or air spring pressures using scaled adjustment.
a. one or more sensors for determining acceleration data of the vehicle;
b. one or more timers for determining a time interval since a previous adjustment of said suspension height or air spring pressure; and c. a processor receiving suspension heights, air spring pressure readings, acceleration data and time interval data and comprising one or more algorithms for determining if a maximum time interval has passed since the previous adjustment; determining if a normal time interval has passed since the previous adjustment, if the maximum time interval has not passed; taking a further vehicle Date Recue/Date Received 2020-07-29 acceleration measurement if the normal time interval has also not been reached, or if a normal time interval has been reached but acceleration is not below a predetermined threshold value; if the maximum time interval has been reached;
or if the normal time interval has been reached and acceleration is below the predetermined threshold, then performing an adjustment cycle series of steps as follows:
i. determining suspension height or air spring pressures;
ii. assessing suspension height or air spring pressures using predetermined criteria to determine if the suspension heights or air spring pressures require adjustment;
iii. calculating a scaled adjustment of the suspension heights or air spring pressures, based on vehicle acceleration;
iv. adjusting suspension heights or air spring pressures using scaled adjustment.
14. A method for averaging fluctuations in suspension height or air pressure readings of one or more air spring suspensions in a multi-rear axle vehicle and for performing an adjustment cycle series of steps for adjusting said suspension height and air spring pressure readings; the method comprising the steps of:
a. determining acceleration of the vehicle;
b. determining if a maximum time interval has passed since a previous adjustment cycle series of steps was run;
c. determining if a normal time interval has passed since the previous adjustment cycle series of steps, if the maximum time interval has not passed;
d. taking a further vehicle acceleration measurement if the normal time interval has also not been reached, or if a normal time interval has been reached but acceleration is not below a predetermined threshold value; and Date Recue/Date Received 2020-07-29 e. if the maximum time interval has been reached; or if the normal time interval has been reached and acceleration is below the predetermined threshold, then performing the adjustment cycle series of steps as follows:
i. determining suspension height or air spring pressures;
ii. assessing suspension height or air spring pressures using predetermined criteria to determine if the suspension heights or air spring pressures require adjustment;
iii. calculating a scaled adjustment of the suspension heights or air spring pressures, based on vehicle acceleration;
iv_ adjusting suspension heights or air spring pressures using scaled adjustment; and v. repeating steps a. to e.
a. determining acceleration of the vehicle;
b. determining if a maximum time interval has passed since a previous adjustment cycle series of steps was run;
c. determining if a normal time interval has passed since the previous adjustment cycle series of steps, if the maximum time interval has not passed;
d. taking a further vehicle acceleration measurement if the normal time interval has also not been reached, or if a normal time interval has been reached but acceleration is not below a predetermined threshold value; and Date Recue/Date Received 2020-07-29 e. if the maximum time interval has been reached; or if the normal time interval has been reached and acceleration is below the predetermined threshold, then performing the adjustment cycle series of steps as follows:
i. determining suspension height or air spring pressures;
ii. assessing suspension height or air spring pressures using predetermined criteria to determine if the suspension heights or air spring pressures require adjustment;
iii. calculating a scaled adjustment of the suspension heights or air spring pressures, based on vehicle acceleration;
iv_ adjusting suspension heights or air spring pressures using scaled adjustment; and v. repeating steps a. to e.
15. The method of claim 14, wherein using the scaled adjustment to adjust suspension heights or air spring pressure comprises using acceleration data to adjust a confidence factor associated with the suspension height or air spring pressure;
16. The method of claim 15, wherein adjusting a confidence factor comprises initially setting the confidence factor to 1.0, correlating to a full confidence in suspension height or air spring pressure and subsequently decreasing the confidence factor based on acceleration data.
17. A method for configuring suspension ratios in a multi-rear axle vehicle, said vehicle having a drive axle suspension and at least one tag axle suspension, and for adjusting said air suspension pressures, the method comprising the steps of:
a) taking air suspension pressure readings;
b) determining acceleration data of the vehicle;
c) performing an adjustment cycle series of steps as follows:
i. assessing air suspension pressures using predetermined criteria to determine if the air spring pressures require adjustment;
Date Recue/Date Received 2020-07-29 ii. calculating a scaled adjustment of the air suspension pressures, based on vehicle acceleration; and iii. adjusting air suspension pressures using scaled adjustment;
d) monitoring ride height of the vehicle; and e) sending adjusted air suspension pressure measurements and ride height inputs to a processor, said processor performing the steps of:
i. calculating the suspension ratio of adjusted air suspension pressures between the one or more tag suspensions and the drive suspension, ii. determining a driving condition based on ride height inputs;
iii.
comparing the calculated suspension ratio against a predetermined suspension ratio of air pressure for said driving condition; and iv.
adjusting air pressure in any one or more of said one or more air suspensions to set the suspension ratio of air pressure to the predetermined suspension ratio of air pressure.
Date Recue/Date Received 2020-07-29
a) taking air suspension pressure readings;
b) determining acceleration data of the vehicle;
c) performing an adjustment cycle series of steps as follows:
i. assessing air suspension pressures using predetermined criteria to determine if the air spring pressures require adjustment;
Date Recue/Date Received 2020-07-29 ii. calculating a scaled adjustment of the air suspension pressures, based on vehicle acceleration; and iii. adjusting air suspension pressures using scaled adjustment;
d) monitoring ride height of the vehicle; and e) sending adjusted air suspension pressure measurements and ride height inputs to a processor, said processor performing the steps of:
i. calculating the suspension ratio of adjusted air suspension pressures between the one or more tag suspensions and the drive suspension, ii. determining a driving condition based on ride height inputs;
iii.
comparing the calculated suspension ratio against a predetermined suspension ratio of air pressure for said driving condition; and iv.
adjusting air pressure in any one or more of said one or more air suspensions to set the suspension ratio of air pressure to the predetermined suspension ratio of air pressure.
Date Recue/Date Received 2020-07-29
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3088369A CA3088369A1 (en) | 2020-07-29 | 2020-07-29 | Electronic suspension control system for a vehicle |
| CA3126248A CA3126248A1 (en) | 2020-07-29 | 2021-07-29 | Electronic suspension control system for a vehicle |
| US17/388,880 US11618295B2 (en) | 2020-07-29 | 2021-07-29 | Electronic suspension control system for a vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3088369A CA3088369A1 (en) | 2020-07-29 | 2020-07-29 | Electronic suspension control system for a vehicle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA3088369A1 true CA3088369A1 (en) | 2022-01-29 |
Family
ID=80081240
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA3088369A Abandoned CA3088369A1 (en) | 2020-07-29 | 2020-07-29 | Electronic suspension control system for a vehicle |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA3088369A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220032716A1 (en) * | 2019-05-10 | 2022-02-03 | Zf Cv Systems Hannover Gmbh | Method for controlling an air suspension system of a vehicle |
-
2020
- 2020-07-29 CA CA3088369A patent/CA3088369A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220032716A1 (en) * | 2019-05-10 | 2022-02-03 | Zf Cv Systems Hannover Gmbh | Method for controlling an air suspension system of a vehicle |
| US11685216B2 (en) * | 2019-05-10 | 2023-06-27 | Zf Cv Systems Hannover Gmbh | Method for controlling an air suspension system of a vehicle |
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| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |
Effective date: 20240130 |