SE539410C2 - System and method for improved vehicle stability by controlling a pneumatic park brake circuit arrangement - Google Patents

System and method for improved vehicle stability by controlling a pneumatic park brake circuit arrangement Download PDF

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Publication number
SE539410C2
SE539410C2 SE1451591A SE1451591A SE539410C2 SE 539410 C2 SE539410 C2 SE 539410C2 SE 1451591 A SE1451591 A SE 1451591A SE 1451591 A SE1451591 A SE 1451591A SE 539410 C2 SE539410 C2 SE 539410C2
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SE
Sweden
Prior art keywords
air pressure
braking
pressure value
vehicle
brake circuit
Prior art date
Application number
SE1451591A
Other languages
Swedish (sv)
Other versions
SE1451591A1 (en
Inventor
Thorsell Johan
Original Assignee
Scania Cv Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Scania Cv Ab filed Critical Scania Cv Ab
Priority to SE1451591A priority Critical patent/SE539410C2/en
Priority to DE102015015239.4A priority patent/DE102015015239A1/en
Publication of SE1451591A1 publication Critical patent/SE1451591A1/en
Publication of SE539410C2 publication Critical patent/SE539410C2/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/24—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being gaseous
    • B60T13/26—Compressed-air systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/24—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being gaseous
    • B60T13/26—Compressed-air systems
    • B60T13/38—Brakes applied by springs or weights and released by compressed air
    • B60T13/385—Control arrangements therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/66—Electrical control in fluid-pressure brake systems
    • B60T13/662—Electrical control in fluid-pressure brake systems characterised by specified functions of the control system components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/66—Electrical control in fluid-pressure brake systems
    • B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
    • B60T13/683—Electrical control in fluid-pressure brake systems by electrically-controlled valves in pneumatic systems or parts thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T7/00—Brake-action initiating means
    • B60T7/02—Brake-action initiating means for personal initiation
    • B60T7/08—Brake-action initiating means for personal initiation hand actuated
    • B60T7/10—Disposition of hand control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T7/00—Brake-action initiating means
    • B60T7/12—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger
    • B60T7/20—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger specially for trailers, e.g. in case of uncoupling of or overrunning by trailer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/24—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being gaseous
    • B60T13/26—Compressed-air systems
    • B60T13/261—Compressed-air systems systems with both indirect application and application by springs or weights and released by compressed air
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/1755—Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve
    • B60T8/17558—Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve specially adapted for collision avoidance or collision mitigation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/176—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS
    • B60T8/1761—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS responsive to wheel or brake dynamics, e.g. wheel slip, wheel acceleration or rate of change of brake fluid pressure
    • B60T8/17616—Microprocessor-based systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
    • B60W30/02—Control of vehicle driving stability
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
    • B60W30/18—Propelling the vehicle
    • B60W30/18172—Preventing, or responsive to skidding of wheels

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Regulating Braking Force (AREA)

Abstract

ABSTRACT The invention relates to a method for improved vehicle stability by controlling a pneumaticpark brake circuit arrangement when using said park brake circuit arrangement for braking,said park brake circuit arrangement comprising braking means for the wheels of at least two wheel axles of said vehicle, comprising the steps of: - continuously determining (s410) an air pressure (P) of said pneumatic park brake circuit alTa ngement; - activating (s420) braking by said braking means of said pneumatic park brake circuit alTa ngement; - determining (s430) an air pressure value (Px) at which braking means (BI\/|2a; BI\/|2b) of atleast one wheel axle (WA2) of said at least two wheel axles (WA1, WA2) is limited regarding braking action; - controlling (s440) an air pressure valve unit (260) for the braking means (BI\/|2a; BI\/|2b) ofsaid at least one wheel (WA2) axle so that braking action is limited to a predetermined level (Fx) corresponding to said determined air pressure value (Px). The invention relates also to a computer programme product comprising program code (P)for a computer (200; 210) for implementing a method according to the invention. Theinvention relates also to a system for improved vehicle stability and a vehicle equipped with the system. Figure 2 for publication

Description

System and method for improved vehicle stability by control of a pneumatic park brake circuit arrangement TECHNICAL FIELD The present invention relates to a method for improved vehicle stability by controlling apneumatic park brake circuit arrangement when using said park brake circuit arrangementfor braking. The invention relates also to a computer program product comprising programcode for a computer for implementing a method according to the invention. lt relates also toa system for improved vehicle stability by controlling a pneumatic park brake circuitarrangement when using said park brake circuit arrangement for braking and a motor vehicle equipped with the system.
BACKGROUND I\/lotor vehicles of today are equipped with a parking brake circuit for use when the vehicle isstanding still, such as when being parked between different time periods of operation or inother situations, whenever applicable. A braking force is hereby applied by means of amanually operated manoeuvre means such as a parking brake lever. This parking brakecircuit is separated from one or more brake circuits which are used during propulsion of saidvehicle, such as conventional brake circuits being arranged to decelerate the vehicle either by means of a manually operated brake pedal or by automatically operated control systems. lt is known to use said parking brake circuit also in case of emergency or any other situationrequiring a relatively large amount of braking force for reducing speed of said vehicle. ln thisway an operator ofthe vehicle may use said parking brake circuit for applying additionalbraking force to said one or more service brake circuits for more effectively braking said vehicle.
However, use of said parking brake circuit during propulsion ofthe vehicle is associated witha number of drawbacks. The parking brake circuit may be used as emergency braking means in case said conventional brake circuits are failing or providing insufficient braking force for decelerating the vehicle. lt is known to be difficult for an operator to control the park brakecircuit for achieving a desired braking force. Only highly experienced operators are normallycapable of controlling said park brake circuit by means of said parking brake lever andachieve high vehicle deceleration. ln case the park brake circuit is not operated in anappropriate way said vehicle may be instable and hereby start to rotate about a vertical axisthereof. This may naturally result in dangerous situations, not only regarding the operatorand passengers ofthe vehicle, but also regarding other vehicles, humans or constructions/objects being present in the vicinity of the instable vehicle. ln case park brake chambers of different wheel axles ofthe vehicle are not properly set the vehicle may be instable even before the vehicle reaches an acceptable retardation. A furtherdrawback of park brake circuits of today is that a required braking force may not be providedwhen all brake chambers are activated at a certain air pressure ofthe park brake circuit, due to that the air pressure of all brake chambers should be substantially equal.
There is thus a need for providing a reliable park brake circuit which provides safeapplication of braking force during propulsion ofthe vehicle so that instability of is avoided or reduced.
EP 2615003 relates to parking brake module for a pressure operated brake system of a vehicle being suitable for coupling a trailer.
SUMMARY OF THE INVENTION An object of the present invention is to propose a novel and advantageous method for improved vehicle stability.
Another object ofthe invention is to propose a novel and advantageous system and a novel and advantageous computer program for improved vehicle stability.
Yet another object ofthe invention is to propose a method, a system and a computerprogram pertaining to safe emergency braking of a vehicle where a state of instability is avoided.
Yet another object ofthe invention is to propose a method, a system and a computer program for improved vehicle stability during a braking of said vehicle.
Yet another object ofthe invention is to propose an alternative method, an alternative system and an alternative computer program for improved vehicle stability.
Some of these objects are achieved with a method for improved vehicle stability bycontrolling a pneumatic park brake circuit arrangement when using said park brake circuitarrangement for braking, said park brake circuit arrangement comprising braking means forthe wheels of at least two wheel axles of said vehicle according to claim 1. Other objects areachieved with a system according to claim 6. Advantageous embodiments are depicted inthe dependent claims. Substantially the same advantages of method steps ofthe innovative method hold true for corresponding means of the innovative system.
According to an aspect of the invention there is provided a method for improved vehiclestability by controlling a pneumatic park brake circuit arrangement when using said parkbrake circuit arrangement for braking, said park brake circuit arrangement comprisingbraking means for the wheels of at least two wheel axles of said vehicle, comprising the steps of: - continuously determining an air pressure of said pneumatic park brake circuit alTa ngement; - activating braking by said braking means of said pneumatic park brake circuit arrangement; - determining an air pressure value at which braking means of at least one wheel axle of said at least two wheel axles is limited regarding braking action; - controlling an air pressure valve unit for the braking means of said at least one wheel axleso that braking action is limited to a predetermined level corresponding to said determined air pressure value.
Hereby is advantageously achieved facilitated parking brake control for an operator of thevehicle, in particular during emergency situations or other situations where the vehicle speed has to be reduced with a relatively short period of time.
Hereby the vehicle advantageously maintains stability when activating said park brake circuitduring propulsion of the vehicle, which in turn renders improved traffic safety and reduction of collision risk.
Hereby is also achieved improved use of prevailing park brake means being provided atvarious wheel axles of the vehicle. Further, brake force blending regarding conventional brakes and brakes ofthe park brake circuit is facilitated.
According to an aspect of the invention the braking forces of braking means at one or morewheel axles not being a foremost wheel axle are limited, so as to achieve a controlleddeceleration of said vehicle. According to an embodiment only the braking means beingprovided at a most rear position of the vehicle is controlled so as to limit braking force thereof during deceleration of the vehicle.Said braking may be related to an emergency braking situation.The method may comprise the step of: - controlling said braking action of said braking means by controlling an air pressure of abrake chamber of said braking means so that said braking action is increased by loweringsaid air pressure of said brake chamber, and vice versa. Hereby is achieved an accurate androbust controlling of said braking action. This advantageously provides a reliable and safe deceleration of said vehicle.The method may comprise the step of: - controlling said braking action of said braking means by controlling an air pressure of abrake chamber of said braking means so that said braking action is increased by loweringsaid air pressure of said brake chamber and so that said braking action is decreased by increasing said air pressure of said brake chamber.
The method may comprise the step of: - determining said air pressure value as a predetermined air pressure value. Hereby isachieved a simple, efficient and predictable way of determining said air pressure value, which is associated with minimal computational burden of control units ofthe vehicle.
The method may comprise the step of: - determining said air pressure value on the basis of information regarding at least one ofthecircumstances: vehicle configuration, vehicle mass, vehicle speed, lateral acceleration andyaw rate of said vehicle and steering angle of said vehicle. Hereby said air pressure valuemay be determined with high accuracy. By considering e.g. prevailing lateral accelerationand prevailing yaw rate of said vehicle said pressure value may be determined so as to minimize instability of said vehicle during braking by means of said park brake circuit.
The method may comprise the steps of: - continuously determining a development of said air pressure value; - continuously considering the slope of said development of said air pressure value; - controlling an air pressure valve unit for the braking means of said at least one wheel axleon the basis of said slope of said air pressure value so as to limit said braking action to saidpredetermined level substantially at the same time as said air pressure value reaches saiddetermined air pressure value. Hereby said air pressure value may be determined with highaccuracy. ln case said slope of said development of said air pressure value is relatively steepsaid air pressure value is determined to also be relatively high, meaning that a relatively small braking force is applied during said limitation of braking force.
According to an aspect of the invention there is provided a system for improved vehiclestability arranged to control a pneumatic park brake circuit arrangement when using saidpark brake circuit arrangement for braking, said park brake circuit arrangement comprising braking means for the wheels of at least two wheel axles of said vehicle, comprising: - means for continuously determining an air pressure of said pneumatic park brake circuit alTa ngement; - means for activating braking by said braking means of said pneumatic park brake circuit alTa ngement; - means for determining an air pressure value at which braking means of at least one wheel axle of said at least two wheel axles is limited regarding braking action; - means for controlling an air pressure valve unit for the braking means of said at least onewheel axle so that braking action is limited to a predetermined level corresponding to said determined air pressure value.
The innovative system may comprise either an electrically controlled park brake circuit or a pneumatically controlled park brake circuit.
Said air pressure valve unit is according to an embodiment an electrically/electronicallycontrolled valve unit. Hereby is achieved an accurate and swift activation of said limitation ofbrake force. When said valve unit is activated air pressure of said braking chambers aresubstantially maintained, thus rendering a limitation of said braking means at said at leastone wheel axle. According to an embodiment an air pressure valve unit is provided andcontrolled according to the invention for each of a number of parallel park brake circuits of the vehicle.The system may comprise: - means for controlling said braking action of said braking means by controlling an airpressure of a brake chamber of said braking means so that said braking action is increased by lowering said air pressure of said brake chamber, and vice versa.The system may comprise: - means for controlling said braking action of said braking means by controlling an airpressure of a brake chamber of said braking means so that said braking action is increasedby lowering said air pressure of said brake chamber and so that said braking action is decreased by increasing said air pressure of said brake chamber.The system may comprise:- means for determining said air pressure value as a predetermined air pressure value.
The system may comprise: - means for determining said air pressure value on the basis of information regarding at leastone ofthe circumstances: vehicle configuration vehicle mass, vehicle speed, lateral acceleration and yaw rate of said vehicle and steering angle of said vehicle.The system may comprise:- means for continuously determining a development of said air pressure value; - means for continuously considering the slope of said development of said air pressure value; - means for controlling an air pressure valve unit for the braking means of said at least onewheel axle on the basis of said slope of said air pressure value so as to limit said brakingaction to said predetermined level substantially at the same time as said air pressure value reaches said determined air pressure value.
At the system said air pressure valve unit may be arranged so that substantially no brakingaction is available when said pressure valve unit is open and so that said braking action is limited constant level when said pressure valve unit is closed.
Said air pressure valve unit may be arranged to be electrically and/or pneumatically operated. Hereby a versatile system according to an aspect ofthe invention is provided.
According to an aspect of the invention there is provided a vehicle comprising a systemaccording to what is presented herein. Said vehicle may be a motor vehicle. Said vehicle may be any from among a truck or a bus.
According to an aspect of the invention there is provided a computer program for improvedvehicle stability by controlling a pneumatic park brake circuit arrangement when using saidpark brake circuit arrangement for braking, said park brake circuit arrangement comprisingbraking means for the wheels of at least two wheel axles of said vehicle, wherein saidcomputer program comprises program code for causing an electronic control unit or acomputer connected to the electronic control unit to perform the steps according to any of the claims 1-5, when run on said electronic control unit or said computer.
According to an aspect of the invention there is provided a computer program for improvedvehicle stability by controlling a pneumatic park brake circuit arrangement when using saidpark brake circuit arrangement for braking, said park brake circuit arrangement comprisingbraking means for the wheels of at least two wheel axles of said vehicle, wherein saidcomputer program comprises program code stored on a computer-readable medium forcausing an electronic control unit or a computer connected to the electronic control unit to perform the steps according to any of the claims 1-5.
According to an aspect of the invention there is provided a computer program for improvedvehicle stability by controlling a pneumatic park brake circuit arrangement when using saidpark brake circuit arrangement for braking, said park brake circuit arrangement comprisingbraking means for the wheels of at least two wheel axles of said vehicle, wherein saidcomputer program comprises program code stored on a computer-readable medium forcausing an electronic control unit or a computer connected to the electronic control unit toperform the steps according to any ofthe claims 1-5, when run on said electronic control unit or said computer.
According to an aspect of the invention there is provided a computer program productcontaining a program code stored on a computer-readable medium for performing methodsteps according to any of claims 1-5, when said computer program is run on an electronic control unit or a computer connected to the electronic control unit.
According to an aspect of the invention there is provided a computer program productcontaining a program code stored non-volatile on a computer-readable medium forperforming method steps according to any of claims 1-5, when said computer program is run on an electronic control unit or a computer connected to the electronic control unit.
Further objects, advantages and novel features of the present invention will becomeapparent to one skilled in the art from the following details, and also by putting theinvention into practice. Whereas the invention is described below, it should be noted that it is not confined to the specific details described. One skilled in the art having access to the teachings herein will recognise further applications, modifications and incorporations in other fields, which are within the scope ofthe invention.
BRIEF DESCRIPTION OF THE DRAWINGS For fuller understanding of the present invention and its further objects and advantages, thedetailed description set out below should be read in conjunction with the accompanyingdrawings, in which the same reference notations denote similar items in the various diagrams, and in which: Figure 1 schematically illustrates a vehicle according to an embodiment ofthe invention;Figure 2 schematically illustrates a subsystem for the vehicle depicted in Figure 1, accordingto an embodiment of the invention; Figure 3a schematically illustrates a diagram according to an embodiment of the invention;Figure 3b schematically illustrates a diagram according to an embodiment of the invention;Figure 4a is a schematic flowchart of a method according to an embodiment of theinvention; Figure 4b is a more detailed schematic flowchart of a method according to an embodimentof the invention; and Figure 5 schematically illustrates a computer according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS With reference to Figure 1 there is illustrated a side view of a vehicle 100. The exemplifiedvehicle 100 comprises a tractor unit 110 and a trailer 112. The vehicle may be a heavy vehicle, e.g. a truck or a bus.
Even though the vehicle herein is exemplified by a lorry it should be noted that the presentinvention is applicable to various suitable vehicles, such as e.g. forest machines, miningvehicles, heavy duty vehicles, construction vehicles, rescue vehicles, etc. The vehicle mayhave any suitable configuration, e.g. comprising one or more units, including at least one trailer.
The tractor unit 100 is according to an embodiment provided with two wheel axles, a first,front wheel axle WA1 and a second, rear axle WA2. The present invention is howeverapplicable to any vehicle having at least two wheel axles, such as three or four wheel axles.Hereby any suitable limitation of braking means of any suitable wheel axle may be activatedaccording to the innovative method. Limitation of braking force by means of braking meansof two or more wheel axles may be mutually different according to an embodiment of the invention.
The term ”link” refers herein to a communication link which may be a physical connectionsuch as an opto-electronic communication line, or a non-physical connection such as awireless connection, e.g. a radio link or microwave link. Herein provided links are illustratedas being arranged for bi-directional communication. However, in some cases communication between units via such a link may be one-directional.
Figure 2 schematically illustrates a subsystem 289 ofthe vehicle 100. The subsystem 289comprises a pneumatic park brake circuit arrangement. The subsystem is provided in the tractor unit 110.
The subsystem 289 comprises a so-called EPB-unit (Electro-pneumatic Brake system) 220.Said EPB-unit 220 is arranged to provide a pneumatic pressure P in a first front circuit 221.Said EPB-unit 220 is arranged to provide pressurized air to a first front braking means BM1aand a second front braking means BI\/|1b, which are arranged to brake a first front wheelW1a and a second front wheel W1b, respectively. Said first front circuit 221 may comprise atleast one passage arranged to provide said pressurized air to said first front braking meansBM1a and said second front braking means BM1b. Said first front braking means BM1a andsaid second front braking means BI\/|1b comprises according to an embodiment a respectivebrake chamber. Said EPB-unit 220 is thus arranged to control a braking force F at said firstfront wheel W1a and said second front wheel W1b by means of controlling said air pressureP in said first front circuit 221. Said first front wheel W1a and said second front wheel W1b is arra nged at a first front axle WA1. 11 Said EPB-unit 220 is also arranged to provide a pneumatic pressure P in a second rear circuit222. According to this embodiment said pneumatic pressure P may be substantially the samein the first front circuit 221 and the second rear circuit 222 when said pneumatic park brakecircuit arrangement is at a state of non-braking. Said EPB-unit 220 is arranged to providepressurized air to a first rear braking means BM2a and a second rear braking means BM2b,which are arranged to brake a first rear wheel W2a and a second rear wheel W2b,respectively. Said second rear circuit 222 may comprise at least one passage arranged toprovide said pressurized air to said first rear braking means BI\/|2a and said second rearbraking means BI\/|2b. Said first rear braking means BI\/|1a and second rear braking meansBI\/|2b comprise according to an embodiment a respective brake chamber. Said EPB-unit 220is thus arranged to control a braking force F at said first rear wheel W2a and said second rearwheel W2b by means of controlling said air pressure P in said second rear circuit 222. Saidfirst rear wheel W2a and said second rear wheel W2b are arranged at a rear wheel axle WA2.
A first control unit 200 is arranged for controlling braking action of said braking meansBI\/|1a, BM1b, BI\/|2a, BI\/|2b by controlling an air pressure P of a brake chamber of saidbraking means so that said braking action is increased by lowering said air pressure of saidbrake chamber, and vice versa. Each of said brake chambers is according to an embodimentarranged with a pre-stressed spring device, which is arranged to increase applied brakingforce of an associated wheel when said pressure P drops in said brake chamber.Consequently, said pre-stressed spring device is arranged to decrease applied braking force of an associated wheel when said pressure P increases in said brake chamber.
Said first control unit 200 is arranged for communication with a pressure sensor 250 via alink L250. Said pressure sensor 250 is arranged to continuously or intermittentlydetect/measure/determine a prevailing air pressure P in said second rear circuit 222. Saidpressure sensor 250 is arranged to continuously or intermittently send signals s250comprising information about said prevailing air pressure P in said second rear circuit 222 tosaid first control unit 200 via said link L250. Said pressure sensor 250 is arranged between said EPB-unit 220 and an air pressure valve unit 260. 12 Said first control unit 200 is arranged for communication with said air pressure valve unit260 via a link L260. Said air pressure valve unit 260 is according to this example an electronically controlled valve unit.
Said air pressure valve unit 260 is arranged so that substantially no braking action is availablewhen said pressure valve unit 260 is open. Said air pressure valve unit 260 is arranged sothat said braking action is limited to a constant level when said pressure valve unit 260 isclosed. Hereby an applied braking force F of said second rear circuit 222, i.e. the brakingmeans BM2a and BI\/|2b may be limited to a desired level during braking the vehicle so as toavoid instability. According to this example the braking means of said first front circuit 221 isnot limited during deceleration ofthe vehicle 100 and may thus apply a maximum availablebraking force while a braking force of braking means of one or more rear wheel axle(s) (according to this example said second rear wheel axle WA2) is limited to a desired level.
According to one example there is provided a parking brake control means 280 beingarranged for communication with the first control unit 200 via a link L280. Hereby anoperator ofthe vehicle 100 manually may operate said parking brake control means 280, forexample during emergency braking ofthe vehicle. This is in particular advantageous in a casewhere other conventional brake circuits totally or partly are malfunctioning or in a case where additional applied braking force ofthe vehicle is required. lt should be noted that even though it herein is depicted that said parking brake controlmeans 280 may comprise a parking brake lever other alternatives are also applicable. Saidparking brake control means 280 may thus comprise any suitable device for manual or automatic parking brake control.
Said first control unit 200 is arranged for determining an air pressure value Px at whichbraking means of at least one wheel axle (according to this example the second rear wheel axle WA2) of said at least two wheel axles is limited regarding braking action.
Said first control unit 200 is arranged for controlling said air pressure valve unit 260 for thebraking means of said at least one wheel axle (according to this example the second rear wheel axle WA2) so that braking action is limited to a predetermined level corresponding to 13 said determined air pressure value Px. This is explained in greater detail with reference to the Figures 3a and 3b below.
Said first control unit 200 is arranged for determining said air pressure value Px on the basisof information regarding at least one ofthe circumstances: vehicle configuration, vehiclemass, vehicle speed, lateral acceleration, yaw rate of said vehicle and steering angle of saidvehicle. Said vehicle configuration may relate to number of wheel axles being provided withparking brake means. Said vehicle configuration may relate to a state of a gearbox of thevehicle, e.g. which gear step is engaged and/or a prevailing state of a clutch arrangement ofa transmission of said vehicle. Said first control unit 200 may be arranged for determiningsaid air pressure value Px on the basis of information regarding individual rotating speeds ofthe wheels Wla, Wlb, W2a, W2b. Said first control unit 200 is arranged for determining saidair pressure value Px on the basis of information regarding prevailing air pressures of saidbraking means BI\/|1a, BI\/|1b, BI\/|2a, BI\/|2b. Hereby the first control unit 200 may bearranged to determine a unique air pressure value Px regarding said limitation of brakingaction for braking means of each of said wheel axles. According to one example appliedbraking force regarding a number of wheel axles is limited to a greater extent the furtherback the wheel axle is provided, regarding a direction of propulsion ofthe vehicle 100. Thefirst control unit 200 is hereby arranged to determine at least one of prevailing vehicle mass,prevailing vehicle speed, lateral acceleration, yaw rate of said vehicle and steering angle of said vehicle by any suitable means.
Hereby the first control unit 200 may be arranged continuously determining a developmentof said air pressure value P in said second rear circuit 222 and continuously considering theslope of said development of said air pressure value P. The first control unit 200 is accordingto an example arranged to controlling an air pressure valve unit 260 for the braking means ofsaid at least one wheel axle (according to this example said second wheel axle WA2) on thebasis of said slope of said air pressure value P so as to limit said braking action to saidpredetermined level substantially at the same time as said air pressure value reaches said determined air pressure value Px. 14 According to an embodiment a pre-control of said air pressure valve unit 260 is performed.Hereby a suitable timing allows that the air pressure valve unit 260 is actually completely closed at the point of time when the determined pressure level Px is reached.
A second control unit 210 is arranged for communication with the first control unit 200 via alink L210. The second control unit 210 may be detachably connected to the first control unit200. The second control unit 210 may be a control unit external to the vehicle 100. Thesecond control unit 210 may be adapted to performing the innovative method stepsaccording to the invention. The second control unit 210 may be used to cross-load softwareto the first control unit 200, particularly software for applying the innovative method. Thesecond control unit 210 may alternatively be arranged for communication with the firstcontrol unit 200 via an internal network in the vehicle. The second control unit 210 may beadapted to performing substantially similar functions to those of the first control unit 200such as for example determining said air pressure value Px at which braking means of atleast one wheel axle of said at least two wheel axles is limited regarding braking action andcontrolling said air pressure valve unit for the braking means of said at least one wheel axleso that braking action is limited to a predetermined level corresponding to said determined air pressure value.
According to an embodiment at least one non-return valve is arranged in said park brakecircuits so that if a malfunction regarding controlling of said air pressure valve occurs it would be possible to increase a prevailing air pressure in relevant park brake circuit.
With reference to Figure 3a there is illustrated a diagram according to an embodiment of the invention.
Hereby a prevailing air pressure Pf in the first front circuit 221 is presented as a function oftime t. Also a prevailing air pressure Pr in the second rear circuit 222 is presented as a function of time t. The pressure P is given in bar and the time t is given in seconds s.
Hereby it is presented that the pressure Pr in the second rear circuit 222 is decreased froman initial level P1 at a first time point t1, at which time said manoeuvre means 280 isactivated, i.e. when an operator manoeuvres said means 280 for activating said park brake circuits 221 and 222. According to an aspect ofthe invention said air pressure value Px is determined and at a second time point t2, when said pressures Pf and Pr reaches saiddetermined air pressure value Px, said air pressure valve unit 260 is activated. Hereby thepressure Pr is maintained at a level substantially corresponding to said determined level Pxwhile the pressure Pf is continuing to decrease and hereby also applying higher braking force by means of said braking means BM1a and BI\/|1b.
With reference to Figure 3b there is illustrated a diagram according to an embodiment of the invention.
Hereby a prevailing applied park brake force Ff in the first, front circuit 221 is presented as afunction of time t. Also a prevailing applied park brake force Fr in the second rear circuit 222is presented as a function of time t. The park brake force F is given in Newton and the time t is given in seconds s.
Hereby it is presented that the park brake force Fr in the second rear circuit 222 is increasedfrom an initial level at said first time point t1, at which time said manoeuvre means 280 isactivated, i.e. when an operator manoeuvres said means 280 for activating said park brakecircuits 221 and 222. Paying regard to that said air pressure value Px is determined and thatsaid air pressure valve unit 260 is activated at said second time point t2, said park brakeforces Ff and Fr reach a park brake force corresponding to said determined air pressurevalue Px at this point of time t2. Hereby the park brake force Fr is maintained at a levelsubstantially corresponding to said determined level Px while the park brake force Ff iscontinuing to increase and so as to apply higher braking force by means of said braking means BM1a and BI\/|1b.
By actively limiting the park brake force of said second rear brake circuit 222 while notlimiting the brake force ofthe first front brake circuit 221 is not limited at all, or to a lowerdegree than said second rear brake circuit 222 stability of said vehicle 100 may bemaintained during a deceleration process of the vehicle 100, according to an aspect of the invention.
Figure 4a schematically illustrates a flow chart of a method for improved vehicle stability bycontrolling a pneumatic park brake circuit arrangement 222 when using said park brake circuit arrangement 222 for braking, said park brake circuit arrangement 222 comprising 16 braking means and for the wheels of at least two wheel axles of said vehicle. The methodcomprises a first method step s401. The step s401 comprises the steps of:- continuously determining an air pressure P of said pneumatic park brake circuit arrangement;- activating braking by said braking means of said pneumatic park brake circuit arrangement; - determining an air pressure value Px at which braking means of at least one wheel axle of said at least two wheel axles is limited regarding braking action; - controlling an air pressure valve unit 260 for the braking means of said at least one wheelaxle so that braking action is limited to a predetermined level Fx corresponding to said determined air pressure value Px.After the method step s401 the method ends.
Figure 4b schematically illustrates a flow chart of a method for improved vehicle stability bycontrolling a pneumatic park brake circuit arrangement when using said park brake circuit arrangement for braking, said park brake circuit arrangement comprising braking means forthe wheels of at least two wheel axles of said vehicle. The method comprises a method steps410. The step s410 comprises the step of continuously determining an air pressure P of saidpneumatic park brake circuit arrangement. This is performed by means of said air pressure sensor 250 and said first control unit 200. After the method step s410 a subsequent method step s420 is performed.
The step s420 comprises the step of activating braking by said braking means of saidpneumatic park brake circuit arrangement. This is performed by means of actuating saidparking brake control means 280. This may be performed manually by an operator ofthevehicle 100. According to an alternative embodiment said first control unit 200 is arrangedto automatically activating braking by said braking means of said pneumatic park brakecircuit arrangement. After the method step s420 a subsequent method step s430 is performed.
The step s430 comprises the step of determining an air pressure value Px at which braking means of at least one wheel axle of said at least two wheel axles is limited regarding braking 17 action. This is performed by means of said first control unit 200. This may be performed in many different suitable ways.
According to a first example said air pressure value Px is determined on the basis of aprevailing vehicle mass. Hereby a relatively low air pressure value Px is determined if saidvehicle mass is relatively high. Hereby a relatively high air pressure value Px is determined if said vehicle mass is relatively low.
According to a second example said air pressure value Px is determined on the basis of aprevailing vehicle speed. Hereby a relatively low air pressure value Px is determined if saidvehicle speed is relatively high. Hereby a relatively high air pressure value Px is determined if said vehicle speed is relatively low.
According to a third example said air pressure value Px is determined on the basis of aprevailing lateral acceleration of the vehicle. Hereby a relatively low air pressure value Px isdetermined if said lateral acceleration ofthe vehicle is relatively high. Hereby a relativelyhigh air pressure value Px is determined if said lateral acceleration of the vehicle is relatively low.
According to a fourth example said air pressure value Px is determined on the basis of aprevailing yaw rate of said vehicle. Hereby a relatively low air pressure value Px isdetermined if said yaw rate of said vehicle is relatively low. Hereby a relatively high air pressure value Px is determined if said yaw rate of said vehicle is relatively high.
According to a fifth example said air pressure value Px is determined on the basis of aprevailing steering angle of said vehicle. Hereby a relatively low air pressure value Px isdetermined if said steering angle of said vehicle is relatively high. Hereby a relatively high air pressure value Px is determined if said steering angle of said vehicle is relatively low.
According to an embodiment ofthe innovative method a criterion for limiting said brakingaction according to said determined air pressure value Px is that a prevailing vehicle speed is greater than zero, i.e. that the vehicle is moving/is being propelled.
After the method step s430 a subsequent method step s440 is performed. 18 The step s440 comprises the step of controlling said air pressure valve unit 260 for thebraking means of said at least one wheel axle so that braking action is limited to apredetermined level corresponding to said determined air pressure value Px. This isperformed by means of said first control unit 200, second control unit 210 and/or said EPB- unit 220.After the method step s440 the method ends.
Figure 5 is a diagram of one version of a device 500. The control units 200 and 210 describedwith reference to Figure 2 may in one version comprise the device 500. The device 500comprises a non-volatile memory 520, a data processing unit 510 and a read/write memory550. The non-volatile memory 520 has a first memory element 530 in which a computerprogram, e.g. an operating system, is stored for controlling the function of the device 500.The device 500 further comprises a bus controller, a serial communication port, I/O means,an A/D converter, a time and date input and transfer unit, an event counter and aninterruption controller (not depicted). The non-volatile memory 520 has also a second memory element 540.
According to an aspect of the invention there is provided a computer program P comprisingroutines for improved vehicle stability by controlling a pneumatic park brake circuitarrangement when using said park brake circuit arrangement for braking, said park brakecircuit arrangement comprising braking means for the wheels of at least two wheel axles of said vehicle.
The computer program may comprise routines for continuously determining an air pressureP of said pneumatic park brake circuit arrangement. The computer program may compriseroutines for activating braking by said braking means of said pneumatic park brake circuitarrangement. The computer program may comprise routines for determining an air pressurevalue Px at which braking means of at least one wheel axle of said at least two wheel axles islimited regarding braking action. The computer program may comprise routines forcontrolling an air pressure valve unit for the braking means of said at least one wheel axle sothat braking action is limited to a predetermined level corresponding to said determined air pressure value Px. 19 The computer program may comprise routines for controlling said braking action of saidbraking means by controlling an air pressure of a brake chamber of said braking means sothat said braking action is increased by lowering said air pressure of said brake chamber, and vice versa.
The computer program may comprise routines for determining said air pressure value Px as a predetermined air pressure value.
The computer program may comprise routines for determining said air pressure value Px onthe basis of information regarding at least one of the circumstances: vehicle configuration,vehicle mass, vehicle speed, lateral acceleration of said vehicle, yaw rate of said vehicle and steering angle of said vehicle.
The computer program may comprise routines for continuously determining a developmentof said air pressure value P. The computer program may comprise routines for continuouslyconsidering the slope of said development of said air pressure value P. The computerprogram may comprise routines for controlling an air pressure valve unit for the brakingmeans of said at least one wheel axle on the basis of said slope of said air pressure value P soas to limit said braking action to said predetermined level substantially at the same time as said air pressure value reaches said determined air pressure value Px.
The program P may be stored in an executable form or in compressed form in a memory 560 and/or in a read/write memory 550.
Where it is stated that the data processing unit 510 performs a certain function, it meansthat it conducts a certain part of the program which is stored in the memory 560 or a certain part ofthe program which is stored in the read/write memory 550.
The data processing device 510 can communicate with a data port 599 via a data bus 515.The non-volatile memory 520 is intended for communication with the data processing unit510 via a data bus 512. The separate memory 560 is intended to communicate with the dataprocessing unit via a data bus 511. The read/write memory 550 is arranged to communicatewith the data processing unit 510 via a data bus 514. The links L210, L220, L250 and L260, for example, may be connected to the data port 599 (see Figure 2).
When data are received on the data port 599, they are stored temporarily in the secondmemory element 540. When input data received have been temporarily stored, the dataprocessing unit 510 will be prepared to conduct code execution as described above.According to one embodiment signals received on the data port 599 comprises informationabout a prevailing pressure P in any park brake circuit of the vehicle 100. According to oneembodiment signals received on the data port 599 comprises information about vehicleconfiguration, vehicle mass, vehicle speed, lateral acceleration of the vehicle, yaw rate ofsaid vehicle and steering angle of said vehicle, etc. The signals received on the data port 299may be used by the device 500 for determining said air pressure value Px at which brakingmeans of at least one wheel axle of said at least two wheel axles is limited regarding brakingaction, and controlling the air pressure valve unit 260 for the braking means of said at leastone wheel axle so that braking action is limited to a predetermined level corresponding to said determined air pressure value Px.
Parts of the methods herein described may be conducted by the device 500 by means of thedata processing unit 510 which runs the program stored in the memory 560 or theread/write memory 550. When the device 500 runs the program, methods herein described are executed.
The foregoing description of the preferred embodiments of the present invention isprovided for illustrative and descriptive purposes. lt is not intended to be exhaustive, nor tolimit the invention to the variants described. Many modifications and variations willobviously suggest themselves to one skilled in the art. The embodiments have been chosenand described in order to best explain the principles ofthe invention and their practicalapplications and thereby make it possible for one skilled in the art to understand theinvention for different embodiments and with the various modifications appropriate to the intended use.

Claims (12)

1. 21 Claims 1. A method for improved vehicle stability by controlling a pneumatic park brake circuitarrangement (289; 221; 222) when using said park brake circuit arrangement (289; 221; 222)for braking, said park brake circuit arrangement (289; 221; 222) comprising braking means(BM1a; BI\/|1b; BI\/|2a; BI\/|2b) for the wheels (W1a; Wlb; W2a; W2b) of at least two wheelaxles (WA1; WA2) of said vehicle (100), comprising the steps of: - continuously determining (s410) an air pressure (P) of said pneumatic park brake circuit arrangement (289; 221; 222); - activating (s420) braking by said braking means (BM1a; BI\/|1b; BM2a; BI\/|2b) of said pneumatic park brake circuit arrangement (289; 221; 222),characterized by the steps of: - determining (s430) an air pressure value (Px) at which braking means (BI\/|2a; BI\/|2b) of atleast one wheel axle (WA2) of said at least two wheel axles is limited regarding braking action; - controlling (s440) an air pressure valve unit (260) for the braking means (BM2a; BM2b) ofsaid at least one wheel axle (WA2) so that braking action is limited to a predetermined level (Fx) corresponding to said determined air pressure value (Px); and~ determšriing :said air pvrazasaire value (Px) as a pvrefír-zterrriiried air pressure vašue.
2. The method according to claim 1, comprising the step of: - controlling said braking action of said braking means (BI\/|2a; BI\/|2b) by controlling an airpressure of a brake chamber of said braking means (BM2a; BI\/|2b) so that said braking action is increased by lowering said air pressure of said brake chamber, and vice versa. v4-3p-åu.)JJ33r?-3"V;v4- . , . . f \ f,:"lf)'l'f3r'>'v\:v\1n c Own/wa "nu" VN-'Ovrcir w 1:: :Û :I 'NP 'x Vwflfsrwlflfll' WrvwmA.....\ :sm _ x \: ... nfv u x. - .ar . .i-s nu - Ä-NÉP nwn- \ I 4 1 m... www ufli: in.zu . n s .- r' 'W nrvxws-'Üfinn +11) far' n-Ff..>,\. i: r.- 2» b e. r.- i. 5
3. The method according to any of claims 1-42, comprising the steps of:- continuously determining a development of said air pressure value (P);- continuously considering the s|ope of said development of said air pressure value (P); - controlling said air pressure valve unit (260) for the braking means (BI\/|2a; BM2b) of said atleast one wheel axle on the basis of said s|ope of said air pressure value (P) so as to limit saidbraking action to said predetermined level (Fx) substantially at the same time (t2) as said air pressure value (P) reaches said determined air pressure value (Px). åå. A system for improved vehicle stability arranged to control a pneumatic park brakecircuit arrangement (289; 221; 222) when using said park brake circuit arrangement (289;221; 222) for braking, said park brake circuit arrangement (289; 221; 222) comprising brakingmeans (BI\/|1a; BI\/llb; BI\/|2a; BI\/|2b) for the wheels (W1a; Wlb; W2a; W2b) of at least two wheel axles (WA1; WA2) of said vehicle, comprising: - means (200; 210; 500; 250) for continuously determining an air pressure (P) of said pneumatic park brake circuit arrangement (289; 221; 222); - means (200; 210; 500; 280) for activating braking by said braking means (BM1a; BI\/|1b;BI\/|2a; BM2b) of said pneumatic park brake circuit arrangement (289; 221; 222), characterized by: - means (200; 210; 500) for determining an air pressure value (Px) at which braking means(BM2a; BM2b) of at least one wheel axle (WA2) of said at least two wheel axles (WA1; WA2) is limited regarding braking action; - means (200; 210; 500) for controlling an air pressure valve unit (260) for the braking means(BM2a; BM2b) of said at least one wheel axle (WA2) so that braking action is limited to a predetermined level (Fx) corresponding to said determined air pressure value (Px); and 23 -» rmaans QGO; Zlü' EGO) for câeterrninizfg said air pressure value (Wi as a predetermined air pressure value. ïšâ. The system according to claim š-å, comprising: - means (200; 210; 500) for controlling said braking action of said braking means bycontrolling an air pressure of a brake chamber of said braking means so that said braking action is increased by lowering said air pressure of said brake chamber, and vice versa.Q Ti n x +13 'n ß n É +n filfihfvx :Il ~ "F nrvxn~§f'nn'a. ...s y WH. . c Wang- ._ _, . _, ,..,,..s...,,. z-wofsn fÜíïl-S- '71 Û~ ï-'l-Sffi fnr Åni-rnvvvzïnšififw 1:4 'air mrrwcwnfln w-Nino fl-'vï fu' ”i z~\r^¶rån-E~f>r'vv\És/\f>r~l ~ :r-r. .:;_ _,......,.. 51.- .\,m<:<:b.:4 .< n wwcnrnwi l' mfinrwl -\.~~ ufilnr-vlfi n r 0:4 n-'nn r-'ri- .~ å: Hfiš vwlr-Éviflt »avi *fšfltnrïrn *sr win V? :W :fåi .-\.: u.: u; yuu nu :m 1; . u i. \ »m Uumü» _; uu _. s _ _. .sig _. nu -íêg The system according to any of claims ê_¿i¿-9§>_, comprising: - means (200; 210; 500; 250) for continuously determining a development of said air pressure value (P); - means (200; 210; 500) for continuously considering the slope of said development of said air pressure value (P); - means (200; 210; 500) for controlling said air pressure valve unit (260) for the brakingmeans of said at least one wheel axle on the basis of said slope of said air pressure value (P)so as to limit said braking action to said predetermined level substantially at the same time as said air pressure value reaches said determined air pressure value (Px). 442. The system according to any of claims éšå-ëaí-lflå, wherein said air pressure valve unit (260) is arranged so that substantially no braking action is available when said pressure valve unit 24 (260) is open and so that said braking action is limited constant level when said pressure valve unit is closed. êfåfqj. The system according to any of claims ëf-êfšffflif, wherein said air pressure valve unit (260) is arranged to be electrically and/or pneumatically operated.êåfi. A vehicle (100; 110) comprising a system according to any one of claims -ä-QÅåJ älg. The vehicle (100; 110) according to claim 3632, which vehicle is any from among a truck or a bus. A computer program (P) for improved vehicle stability arranged to control apneumatic park brake circuit arrangement when using said park brake circuit arrangementfor braking, said park brake circuit arrangement comprising braking means for the wheels ofat least two wheel axles of said vehicle, wherein said computer program (P) comprisesprogram code for causing an electronic control unit (200; 500) or another computer (210;500) connected to the electronic control unit (200; 500) to perform the steps according to any of the claims l-âfå. êëgng. A computer program product containing a program code stored on a computer-readable medium for performing method steps according to any of claims l-åå, when saidcomputer program is run on an electronic control unit (200; 500) or a computer (210; 500) connected to the electronic control unit (200; 500).
SE1451591A 2014-12-19 2014-12-19 System and method for improved vehicle stability by controlling a pneumatic park brake circuit arrangement SE539410C2 (en)

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