SE534039C2 - Method and system for transmitting a control signal - Google Patents

Abstract

The invention relates to a method of transmitting a control signal with desired information content between at least two different units in a vehicle comprising a fluid line system with a fluid intended for transmitting a working pressure. The invention is achieved in that the control signal is transmitted via a fluid line system arranged in the vehicle and superimposed on the working pressure present in the fluid line system. The invention also relates to a system for transmitting a control signal with the desired information content between at least two different units in a vehicle. (Figure 4)

Description

25 30 35 534 039 If an injury or fault occurs in the brake line system, e.g. by an object hitting a brake line, it can lead to a break and a greater or lesser leak can occur. If the break is large, the pressure in the piping system leaks out in a few seconds. Even a coupling, a brake pipe or a brake hose can break due to corrosion, wear or age and start to leak. If the compressed air leaks out of the pipe system quickly, this can result in an almost instantaneous application of one or more of the vehicle's parking brakes.

If this error occurs while driving, it is easy to see that the parking brakes risk striking with full force, which can lead to serious accidents, the driver can lose control of the vehicle and skid off the road or the vehicle can brake uncontrollably, leaving behind road users to drive into the vehicle from behind .

The different brake members may also be applied at slightly different times depending on where the brake line system is damaged and begins to leak. If only one or a few wheels are braked, this can also lead to difficulties for the driver to master the vehicle and keep it on the road.

The brakes are thus applied if the pressure in the vehicle's brake line system drops below a certain level, regardless of whether it occurs on the driver's initiative or if it occurs due to a leak.

To solve this problem, it is of course possible to install electronic monitoring and control systems that regulate the various brake cylinders, but this means extensive changes in the design of the vehicle and brake systems, which automatically entails significant additional costs. Major changes in the design of the vehicle and brake line system should therefore be avoided.

A system is thus needed that enables a simple transmission of control signals from e.g. the driver's seat to the vehicle's brakes and via which information can be transmitted to the parking brake (brake actuator cylinder) that a pressure drop in the system is in fact intentionally initiated by the driver and thus must result in an application of the brakes. If the pressure drop in the brake line system is not initiated by the driver but is unintentional and due to a leak, for example, the brakes should not be applied momentarily but delayed or applied gradually so that the driver has time to drive the vehicle to the side and park safely. The problem is to transfer this information in a cost-effective way. The only existing and practically usable communication channel between the driver's seat and the parking brakes is the parking brake line system.

Prior art shows in different ways to utilize one and the same existing management system to achieve different functions.

US5918634 describes a method of using the same pneumatic line in a locomotive to control both the service brake and the emergency brake. The method is to release the pressure in the brake line gradually and in a controlled manner during normal braking and quickly during emergency braking. A quick emptying gives a rapid pressure drop, which, you could say, becomes the same as if a leak occurs in the brake line system that leads to an unintentional and uncontrolled pressure drop. This then results in an instantaneous application of the brakes, which is thus not desirable according to the present invention.

JP2000153757 similarly describes using a spring brake in an emergency. With intentional application of the brake, the pressure drop takes place gradually in the system, while during emergency braking, the pressure in the brake line system is lowered quickly.

This method thus has similar limitations as US5918634.

EP1063138 describes a system that allows the pressure to drop rapidly down to approx. 1 bar when the parking brake is to be applied. A small pressure is thus left in the brake line system immediately after the vehicle has been parked, which means that the spring force does not work fully and the brake lining is not pressed to the maximum. The driver can then, force against the vehicle's drum or disc brake. for example if the vehicle is parked on a hill, assess whether the parking brake is sufficiently applied and effective. If the vehicle starts to roll with the initially slightly reduced clamping force in the brakes, the position may become worse when the brakes have cooled down.

The remaining pressure in the system is then slowly evacuated and applies the brakes even more strongly, which ensures that the vehicle does not roll away when the brakes cool down and the braking torque otherwise drops.

DE3636139 describes a method which means that one quickly opens an electric pressure regulating valve for a maximum of a short time, so that one immediately reaches the application pressure in the brake cylinder, and only then releases residual pressure under more controlled forms.

The patent documents described above do not prejudge the present invention.

OBJECT OF THE INVENTION AND MOST IMPORTANT CHARACTERISTICS The object of the invention is to solve the above-mentioned problems and to demonstrate a method and a system which makes it possible to transmit control signals via existing line systems in a vehicle in a simple and cost-effective manner.

A further object of the invention is to demonstrate a method and a system for generating, transmitting, receiving and decoding / identifying a control signal between at least two different units in a vehicle.

A further object of the invention is to demonstrate a way of creating signals which can be transmitted in a fluid line system and which as far as possible use the technology and components already present in today's vehicles.

A further object of the invention is to demonstrate a method of eliminating, or at least minimizing, the risk of instantaneous and unintentional application of a vehicle's parking brakes while driving if damage or failure occurs which leads to an uncontrolled pressure drop in the brake line system.

The above-mentioned, and further objects, are achieved according to the invention by a method and a system according to the features stated in claims 1 and 7.

Further features and advantages of the invention will become apparent from the following more detailed description of the invention and from the accompanying drawings and other claims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is described in more detail below in some preferred embodiments with reference to the accompanying drawings.

Figure 1 illustrates a known brake line system in a vehicle.

Figure 2 illustrates the principle of the invention.

Figure 3 illustrates an example of the appearance of a control signal according to the invention.

Figure 4 illustrates a simple flow chart.

Figure 5 illustrates an example of how a transmitter unit or receiver unit according to the invention can be connected to an existing parking brake system.

Figure 6 illustrates a corresponding parking brake system but with the transmitter unit and receiver unit integrated in some of the vehicle's units.

Figure 7 illustrates an alternative system with an electrically and driver-affected control.

Figure 8 illustrates a flow chart of system functions. DESCRIPTION OF PREFERRED EMBODIMENTS The invention thus relates to a method and a system which are intended to transmit signals containing control information over existing fluid lines in a vehicle.

Figure 1 shows an example of a known pneumatic line system 1 in a vehicle (indicated by dash). In this case it is a parking brake system for a heavy / commercial vehicle such as e.g. A truck. A compressed air tank 2 delivers compressed air with a pressure of, for example, 8-10 bar via an operating control 3 arranged in the cab and actuated, for example a pneumatic valve, to one or more parking brakes 4a, b arranged at the vehicle wheel 5, in this application its rear wheels.

Figure 2 shows in principle how a transmitter unit 6 and one or more receiver units 7 can be mechanically / physically connected to the existing parking brake line system 1 in the vehicle.

The transmitter unit 6, which may comprise a signal generator (not shown in more detail), is located in or near the unit, e.g. the control knob 3, which after the driver's initiation ensures that a signal is generated and transmitted, and the receiver unit 7, which may comprise a decoding / identification and control unit (not shown), is located at or near the component or components, e.g. the parking brakes 4a, b in the vehicle, which are intended to be controlled / regulated.

When the vehicle's parking brakes 4a, b are to be caused to perform a predetermined action, e.g. is activated / engaged in a controlled manner, the driver thus initiates the action by manually actuating the control lever 3, whereby the transmitter unit 6 generates a control signal 8.

Figure 3 shows an example of such a control signal 8 with selectable and predetermined properties and can for instance consist of a pressure drop or increase of pressure compared to the working pressure present in the fluid line system 1. By working pressure is meant the pressure fluid in the fluid line system 1 usually 10 15 20 25 30 35 534 039 pours, e.g. when the parking brakes 4a, b are released, ie are not applied. The figure further shows a control signal 8 where the basic pressure or working pressure in the line system 1 is approximately 8 bar. The appearance of the control signal is the simplest imaginable here and the working pressure is superimposed as a pulse with a pressure increase from 8 bar up to 10 bar. The pressure then drops down to, or close to, 0 bar.

The control signal 8 can also be built up by several pressure increases and pressure decreases one after the other or as a combination of pressure increases and pressure decreases. This generates a unique control signal 8 or pulse which has a specific appearance and which is to cause a certain predetermined event. The control signal 8 can thus be said to have been assigned a predetermined information content. The event may be that a certain measure takes place, such as the parking brakes (4a, b) being applied, when the control signal 8 is to cause a certain event in the vehicle. the receiver unit 7, connected somewhere in the line system 1.

The pressure changes of the control signal 8 can, in addition to duration and direction, e.g. increase / decrease in relation to normal working pressure in the line system 1, also defined by different, predetermined, pressure levels.

The signal thus composed is transmitted to the line system 1 and superimposed existing working pressures already present in the line system 1 as it may be pressurized to ensure different functions in the vehicle, as is the case with the parking brakes 4a, b, where a pressure of about 8 bar is applied to keep the parking brakes 4a, b released while driving.

The control signal 8 transmitted by the transmitter unit 6 can be received anywhere in the line system 1 which is in direct fluid contact with the transmitter unit 6. The receiver unit 7 receives the control signal 8 and decodes the control signal 8 on its information content, i.e. a certain determined control signal 8 with a certain appearance and with certain properties provide a certain predetermined action in the receiver unit 7, e.g. generates a certain output signal (pressure level) at its output. This output signal from the receiver 7 is then applied to the component in the vehicle to be regulated / controlled, in this case the parking brakes 4a, b.

Figure 4 shows the principal course of events in a simple flow chart. An initialization (block 12) takes place that a signal is to be generated. The signal is generated (block 13) and then transmitted to and superimposed on the operating pressure present in the fluid line system (block 14). The signal is received and decoded (block 15), after which the intended action is performed (block 16).

Figure 5 shows that in the example of the parking brake system the transmitter unit 6 is suitably connected between the control lever 3 and the control system 1. When the driver wishes to activate the parking brakes 4a, b, the driver manually actuates the control lever 3, said control signal 8 being generated in the transmitter unit 6, e.g. a pulse-shaped pressure increase to 10 bar, see figure 3, the meaning of which is that the air pressure in the parking brakes 4a, b at the wheel 5 of the vehicle must be allowed to be emptied. When the signal reaches the receiver unit 7, the information content of the control signal 8 is decoded and the receiver unit 7 releases the pressure from the brake cylinder of the parking brake 4a, b (not shown). When the pressure drops in the brake cylinders, the braking means (not shown) are normally applied by the action of the strong springs which, when the air pressure drops below a certain level, with great force press the brake pads (not shown) against the vehicle's drum or disc brakes (not shown) .

Figure 6 shows how, instead of arranging separate transmitter units 6 and receiver units 7 in the system, their functions can be integrated with other components in the vehicle. Thus, the transmitter function can be integrated with the driver's control 3 to a combined transmitter unit and control 9. And the receiver function can be integrated with the parking brake to a combined receiver unit and parking brake 10. The receiver function can even more integrally be integrated with the brake actuator.

This rationalizes both the production of the parts and the composition of the vehicle, which saves time and costs in production.

Of course, it is also possible to integrate either the transmitter unit and the control unit or the receiver unit and the brake actuator if appropriate.

Figure 7 shows an alternative way of placing the transmitter unit 6 in the wiring system 1. In this case, the driver's control knob 3 is not pneumatic but electric / electronic, and in the simplest case the control knob 3 may consist of a switch on the vehicle's instrument panel. The control 3 is thus in electrical connection with the transmitter unit 6 via an electrical conductor 11 and when the driver wishes to apply the brakes 4a, b, the driver changes position on the switch whereby a control signal 8 is transmitted via the fluid line system 1 to the receiver unit 7.

Figure 8 shows the course of events in a simple flow chart.

The driver initiates a manual application of the parking brakes (block 17). The system generates a control signal (block 18) which is transmitted to and superimposed on the pressure present in the line system (block 19). The control signal (block 20). When an approved control signal, which means that a subsequent one is received by a receiver unit and decoded lowering in the fluid line system (1) is intentional and approved, is received, the pressure in the parking brake is lowered and the brake is applied (block 21). In the absence of an approved control signal and an increased fluid pressure in the line system, the brakes are released as intended (block 22). If an unintentional pressure drop, e.g. due to a leak, no approved control signal occurs in the control system and a rapid instantaneous application of the brake is prevented (block 23). In the event that a fault occurs in the line system and the pressure drops unintentionally or uncontrolled, the parking brakes are prevented from being applied momentarily. The pressure is instead evacuated gradually and the application takes place in a controlled manner and thus with a certain delay. The invention has been described above with reference to some different preferred embodiments. Of course, the invention is not limited to these, but other variants of the invention are possible within the scope of the claims. Thus, the method can be used generally to transfer information between different units that are connected to a fluid line system, existing but also conceivable in a newly installed one. The control signal 8 can be generated in different ways and given a different appearance, it can for example also be multiplexed. It is also conceivable to use the invention for controlling peripheral equipment for vehicles and which use compressed air.

Claims (10)

10 15 20 30 534 039 11 PAEENTKRAV Method for transmitting a control signal between at least two units in a vehicle, comprising a fluid line system (1) with a fluid intended for transmitting a working pressure, characterized by the method steps, - generation (13) (6) connected to by a fluid control signal ( 8) in a first unit the fluid line system (1), - transmission (14) (1), - reception (15) (7) connected to by the fluid control signal (8) via the fluid line system of the fluid control signal (8) in a second unit the fluid line system ( 1), - identification (15) of the properties and / or information content of the fluid control signal (8), and - control (16) of an additional unit (4a, b) connected to the other unit (7) based on the properties of the fluid control signal (8), and / or information content. Method according to claim 1, characterized by the further method step, - generating a fluid control signal (8) with predetermined properties and / or information content. Method according to claim 1 or 2, characterized by the further method step, - generating (13) a fluid control signal (8) consisting of at least one pressure change in the fluid line system (1) which differs from the working pressure in the fluid line system (1). Method according to one of the preceding claims, characterized by the further method step, over the operating pressure present in - superimposing (14) the fluid control signal (8) on the fluid line system (1). Method according to one of the preceding claims, characterized by the further method step, generating (13) a fluid control signal (8) consisting of an increase in pressure compared with the operating pressure in the fluid line system (1) - Method according to one of the preceding claims, characterized by the further method step, - generating (13) a fluid control signal (8) by raising the pressure in the fluid line system (1) from about 8 to about 10 bar. Method according to one of the preceding claims, characterized by the further method step, «pressure reduction in a parking brake (4a, b) arranged in the vehicle, fluid control signal and application of the parking brake (4a, b), when one (8) is received by the other unit ( 7) which means that a subsequent pressure drop in the fluid line system (1) is intentional and approved. Method according to one of the preceding claims, characterized by the further method strut, - prevention of an instantaneous application of the vehicle parking brake (4a, b), when a fluid control signal (8) has not been received by the receiver unit (7) before a pressure drop occurs in fluid line system (1). System for transmitting a control signal between at least two different units in a vehicle, comprising a fluid line system (1) with a fluid intended for transmitting a working pressure, characterized in that - a transmitter unit (6), connected to the fluid line system ( 1), is arranged to generate a fluid control signal (8) with predetermined properties and / or information content and that the transmitter unit (6) is arranged to transmit the fluid control signal (8) via the fluid present in the fluid line system (1), 534 039 13 that a receiver unit (7), connected to the same fluid line system (1), is arranged to receive the fluid control signal (8) transmitted via the fluid line system (1) and to identify the properties and / or information content of the fluid control signal (8), and - that the receiver unit (7) is furthermore arranged to control a connected further unit (4a, b) on the basis of the properties and / or information content of the fluid control signal (8). System according to claim 9, characterized in that - the fluid control signal (8) consists of at least one pressure change which is arranged to be superimposed on the working pressure present in the fluid line system (1) and which differs from the working pressure in the fluid line system (1).