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
  • 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
  • B60T8/24—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to vehicle inclination or change of direction, e.g. negotiating bends
  • B60T8/248—Trailer sway, e.g. for preventing jackknifing
• • 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

Definitions

• the present invention relates to a method and a system for brake activation on a utility vehicle according to the preambles of claims 1 and 4 respectively.
• a truck with a trailer attached is liable to a problem of the trailer pushing the truck on when travelling down a steep gradient. If the downhill run includes a bend, the truck as it negotiates the bend will be at an angle, as seen in the plane of the road, to the trailer. This means that the pushing force which the trailer exerts on the truck will include a component in the transverse direction of the truck, which component results in a lateral force on the truck's rear wheels. If the lateral force becomes large enough, the truck's rear wheels may lose their grip on the road and start sliding sideways, resulting in the truck-and-trailer combination "folding up" like a jack-knife.
• One way of avoiding this problem is to provide the driver with a special control device which enables him to activate the trailer's brakes without activating the truck's brakes.
• One arrangement for such a solution has traditionally been called a trailer handbrake.
• the trailer's push on the truck on downhill runs can thus be reduced, thereby likewise reducing the risk of the vehicle combination jack-knifing as described above.
• the problem with such a solution is that the trailer's brakes may become overheated if the driver applies the trailer handbrake for too long a distance. The risk of overheating has resulted in the illegality in many countries of solutions which allow the trailer's brakes to be activated separately.
• One object of the invention is to provide a method and a system for preventing or reducing the risk that a utility vehicle comprising a truck and a trailer coupled to it may while in motion become involved in an uncontrollable situation in which an angle between the trailer and the truck, which angle is oriented in a plane substantially horizontal to the road on which the utility vehicle is travelling, decreases so that the utility vehicle tends to "jack-knife".
• Braking data here means data relevant to the functionality of brakes.
• the invention prevents the trailer brakes being subjected to rapid wear or unsuitably high temperatures, which are risks with traditional trailer handbrakes.
• the advantages afforded by the latter are maintained in that the driver can be provided with the possibility of manual intervention to prevent a dangerous situation in which the truck and trailer would risk jack-knifing.
• the filtering which the invention makes possible by monitoring braking data and activating the trailer brakes after "weighing up” these data and the driver's control actions ensures that the trailer can be braked separately without any risk of thereby undermining the functionality of its brakes.
• Braking data preferably comprise the temperature of the trailer brakes.
• Fig. 1 depicts schematically a sideview of a utility vehicle with certain parts visible for the sake of comprehension
• Fig. 2 depicts a flowchart illustrating an embodiment of the method according to the invention.
• Fig. 1 depicts schematically a utility vehicle 1 comprising a truck 2 and a trailer 3 coupled to the truck 2.
• Fig. 1 depicts a truck with trailer
• the invention may also be applied to a tractor unit with semitrailer. Accordingly the expression “trailer” is to be understood here as covering also “semi-trailer”, and the expression “truck” as covering also “tractor unit”.
• the utility vehicle 1 incorporates a pneumatic brake system which comprises truck brakes 4 on the truck 2 and trailer brakes 5 on the trailer 3.
• the brakes 4, 5 are connected to a brake control system 6 which is arranged to control valves in the brake system and hence to control the brakes 4, 5.
• the brake control system 6 may be a so-called EBS system
• the brake control system 6 is arranged to receive via sensors and/or calculate braking data, which are data relevant to the operation of the brakes.
• Braking data may comprise time information about the activation of the brakes, the position of a brake control such as a brake pedal which can be operated by a driver of the truck 2, the vehicle's speed, the vehicle's weight and the topography of the road on which the vehicle travels, i.e. whether it is uphill, downhill or level.
• the road topography may be obtained in a conventional manner on the basis of data about brake pressures and speed changes of the vehicle.
• the road topography may also be obtained on the basis of data about the engine torque and the vehicle's weight.
• Braking data may also comprise the temperature of the trailer brakes, which may be obtained by a method described in EP0594113A1.
• the instantaneous temperature of the brakes is obtained by adding to an initial value temperature increases each calculated on the basis of the instantaneous load state upon brake activation, and subtracting temperature decreases each calculated on the basis of the amount of heat dissipated, which is itself calculated on the basis of a period of time when the brakes are not activated.
• the truck 2 incorporates a trailer brake control means 7 arranged in a driver' s cab incorporated in the vehicle 2 to enable said means to be operated by a driver of the utility vehicle 1.
• the trailer brake control means 7 is a mechanical control means arranged to assume various positions which are infinite in number and are situated between two extreme positions.
• the trailer brake control means 7 may 30 be arranged to assume a finite number of positions between two extreme positions.
• the trailer brake control means 7 may be any other type of suitable control means desired, e.g. it may comprise one or more push-buttons.
• the trailer brake control means 7 is arranged to be in communication with the brake control system 6 whereby the
• brake control system 6 is arranged to receive a trailer brake control signal corresponding to the position of the trailer brake control means 7, which position itself corresponds to a desired trailer brake power.
• the brake control system 6 is arranged to calculate an activation value 10 for activation of the trailer brakes 5 on the basis of the braking data and the trailer brake control signal.
• the activation value may be within a range bounded by values which correspond to full brake power and no brake power.
• the brake system 6 is further arranged to send to the trailer 3 a brake signal corresponding to the activation value.
• the brake signal 15 may be transmitted electrically or pneumatically, depending on whether the trailer 3 is provided with individual operation of the brakes or not.
• Fig. 2 depicts steps in an example of a method according to the invention.
• the trailer brake control means 7 is initially in a position L0 20 in which no trailer brake control signal is sent to the brake control system
• the driver brings the trailer brake control means 7 to a position LI, whereupon a trailer brake control signal corresponding to the desired trailer brake power is sent to the brake control system 6.
• the braking data comprise the current temperature TS of one of the trailer brakes.
• the braking data may comprise the current temperature TS of two or more or all of the trailer brakes.
• the brake control system 6 determines an activation value for activation of the trailer brakes. In a simple version this may mean that if the temperature TS is below a predetermined threshold value TST, the brake control system 6 determines an activation value which corresponds to the desired trailer brake power, whereas if the temperature
• the brake control system 6 determines an activation value which corresponds to no trailer brake power.
• An alternative way of determining the activation value may be as follows. If the trailer brake temperature TS at the time when the brake control system 6 receives the trailer brake control signal is within a predetermined temperature range, the activation value is adapted to the position of the temperature TS in the temperature range. The activation value may be correlated with the temperature so that an inverse linear relationship prevails between them, whereby an activation value corresponding to the desired brake power is determined at the lower limit of the range, and an activation value corresponding to no brake power is determined at the upper limit of the range. Alternatively, a non-linear relationship may prevail between trailer brake temperature and trailer brake activation.
• not only the temperature but also other braking data may be involved in determining the activation value.
• Information stored in the brake system which correlates brake pressure values with times for those values may be used, as also the speed and weight of the utility vehicle 1 and the road topography. This increases the reliability of the system in that a better-adjusted activation value can be obtained, in addition to which a standby method can be initiated if a certain type of braking data is not obtained, e.g. because of a fault.
• the activation value may be determined on the basis of time information about the activation of the brakes, the vehicle's speed, the vehicle's weight and/or the road topography, without regard to the trailer brake temperature, in which case the activation value is related to said braking data to prevent the brake temperature becoming too high.
• the vehicle's brakes 4 may be applied lightly while at the same time the trailer brakes 5 are activated by operating the trailer brake control means 7. This results in a slower temperature increase in the trailer brakes.
• the result of the operation e.g. in the form of the activation value for the trailer brakes, may be presented to the driver on a special display in the cab. This creates a greater possibility of influencing the driver's mode of driving and makes it easier for him/her to adapt the mode of driving to the prevailing conditions.

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• Engineering & Computer Science (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Regulating Braking Force (AREA)
• Valves And Accessory Devices For Braking Systems (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20285531

Family Applications (1)

Country Status (4)

Cited By (5)

Families Citing this family (1)

Citations (5)

• 2001
  • 2001-10-03 SE SE0103289A patent/SE522239C2/sv unknown
• 2002
  • 2002-10-02 BR BRPI0212749-0A patent/BR0212749B1/pt not_active IP Right Cessation
  • 2002-10-02 EP EP02763176A patent/EP1441938A1/en not_active Withdrawn
  • 2002-10-02 WO PCT/SE2002/001788 patent/WO2003029061A1/en not_active Application Discontinuation

Patent Citations (5)

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