GB2036469A

GB2036469A - Control and Distribution of Electrical Power in Motor Vehicles

Info

Publication number: GB2036469A
Application number: GB7935469A
Authority: GB
Original assignee: Centro Ricerche Fiat SCpA
Current assignee: Centro Ricerche Fiat SCpA
Priority date: 1978-10-25
Filing date: 1979-10-12
Publication date: 1980-06-25
Also published as: IT1108413B; SE7908761L; GB2036469B; IT7869451A0; JPH0140284Y2; SE432392B; FR2440024A1; DE2942987A1; FR2440024B1; JPS5561241A; JPS6420034U

Abstract

An electrical power control and distribution system for a motor vehicle includes a processing unit (12) and a distributor unit (32). The processing unit (12), which may include a microprocessor, is connected to switches (18, 20) mounted on the vehicle facia panel and is arranged to directly control low-power electrical equipment (28), in dependence on the switch settings. The distributor unit includes actuators (34), controlled by the control switches (18, 20) via the processing unit (12), which can energise high current electrical equipment (36) via second supply leads (38) of suitably large cross- section. The system enables the length of large cross-section lead to be minimised by appropriate positioning of the distributor unit (32) since the low current leads (30, 26, 16) can be of small cross-section. <IMAGE>

Description

SPECIFICATION System for the Control and Distribution of Electric Power in a Motor Vehicle The present invention relates to a shstem for the control and distribution of electrical power in a motor vehicle having both high- and low-power pieces of electrical equipment which are to be energised from the vehicle's electrical power source (battery, dynamo, or generator) under the control of control switches.

Such a control and distribution system generally consists of a number of supply leads individually connecting the various pieces of equipment with the vehicle's power source. The conductor cross-section of each individual supply lead is related to the power rating of the corresponding piece of equipment.

The passage of electric current through the supply leads is controlled by control switches mounted on the dashboard of the vehicle.

Control and distribution systems of this type require a large number of supply leads, many of which, especially in the case of motor buses for passenger conveyance, are of considerable length. These systems are therefore complicated and costly, and their installation is a long and complicated process.

In order to reduce manufacturing and installation costs, electrical power control and distribution systems have recently been used in which the overall length of supply lead employed is reduced. In these systems, a single large core conductor supply cable is run from the power source to each group of electrical equipments situated adjacent each other in a common area of the vehicle, the connection of the various pieces of equipment to the supply cable being enabled by a number of small control leads.

The purpose of the present invention is to provide a system which will both permit a further reduction in the cost of manufacture by reducing the length of the large cross-section conductor required, and also enable greater simplicity in installation, and greater reliability and safety in operation.

According to the present invention, there is provided a system for the control and distribution of electrical power in a motor vehicle which has both high and low-power pieces of electrical equipment with associated control switches, the system comprising an electronic processing unit electrically energised from the vehicle's electrical power source and connected via first control leads to the control switches and via first supply leads to the pieces of low-power equipment, and a distributor unit connected both to the electrical power source and, via at least one second control lead, to the electronic processing unit, the distributor unit being further connected via second supply leads to the high power pieces of equipment and being provided with a number of actuators each of which is operable to connect the power source to a respective one of the pieces of high-power equipment via a corresponding one of the second supply leads, the processing unit being responsive to operation of the control switches to directly control the energisation of the pieces of low-power equipment via the first supply leads, and to indirectly control energisation of the pieces of high-power equipment by controlling operation of the said actuators via the second control lead or leads.

Such a form of, the electrical power control and distribution system enables a considerable reduction in the amount of conductor material used to be achieved, since the control leads.and the first supply leads need only be of small conductor cross-sections, while the second supply leads which have large conductor crosssections, can generally be made small in length.

Not only is a considerable reduction in cost achieved using the system, but the amount of space needed on board the vehicle for installation of the system is also substantially reduced.

The system also makes possible simplification and amalgamation of the control switches, which can all be arranged to switch to earth thus contributing to improving the safety of the vehicle.

Preferably, the electronic processing unit consists of a microprocessor with associated logic circuits grouped on a number of cards in accordance with their associated vehicle functions. Such an arrangement not only simplifies installation, inspection and maintenance of the processing unit, but also allows variations in the logic of the processing unit for the purpose of modifying the characteristics of the system or to add new modes of operation.

An electrical power control and distribution system embodying the invention will now be particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a block diagram of the control and distribution system; and Figure 2 is a block diagram of the lay-out of the system when applied to a long-bodied motor vehicle.

The electrical power control and distribution system now to be described is arranged to supply electrical power, as required, from the electrical power source 10 (Figure 1) of a motor vehicle (for example, a battery, dynamo, or generator) to various pieces of electrical equipment 28 and 36 of the vehicle. These pieces of equipment are divided into two groups, namely those with a low power rating (equipments 28) and those with a high power rating (equipments 36). The pieces of low-power equipment 28 comprise, for example, warning lights mounted on the vehicle's dashboard (not shown), and small bulbs for illuminating the vehicle's instruments. The high power pieces of equipment 36 comprise, for example, the electric starter motor of the vehicle, the headlamps, the direction indicators, and the brake lights.

The positive pole of the electrical power source 10 is connected, via a supply cable 11, to an electronic processing unit 12.

The electronic processing unit 12 consists of a microprocessor with logic circuits arranged, in known manner, on a number of circuit boards or cards with each card being associated with a particular group of functions. This arrangement facilitates inspection or repairs of the processing unit 12, and enables by means of card replacements, great flexibility in the use of the said unit 12.

The electronic processing unit 12 is earthed at 14, and is provided with a number of inputs, connected, via first control leads 16, to a number of make/break switches 18 and change-over switches 20. The switches 1 8 and 20 are earthed at 22 and 24 respectively and are mounted on the vehicle's dashboard.

The electronic processing unit 12 is provided with a number of outputs, some of which are connected, via first supply leads 26, to the pieces of low-power equipment 36.

The remaining outputs of the electronic processing unit 12 are connected, via second control leads 20 to the inputs of a distributor unit 32. The unit 32 is connected, via a supply cable 33, to the positive pole of the electrical power source 10.

The distributor unit 32 is provided with a number of actuators 34 designed to connect selectively the individual pieces of high-power equipment 38 to the power source 10 via second supply leads 38.

In the example shown, the actuators 34 each consist of a relay comprising an excitation winding 40 and a moving contact 42 cooperating with a pair of fixed contacts 44, 46. One of the fixed contacts 44 is connected to the corresponding second supply lead 38, while the other fixed contact 46 is connected via a safety fuse 48, to the supply cable 33. The winding 40 is connected between the fixed contact 46 and the appropriate one of the second control leads 30.

To energise a particular piece of equipment 36, the corresponding switch 18 or 20 is operated to cause the processing unit 12 to connect the appropriate second control lead to earth at 14.

This results in the corresponding winding 40 being energised which causes the associated contacts 42, 44 and 46 to close and energise the selected piece of equipment 36 via the leads 38.

Instead of being in the form of relays, the actuators 34 of the distributor unit 32 can be formed by power transistors arranged in known manner.

From the foregoing it can be seen that in operation of the Figure 1 system, the processing unit 12 is arranged to directly energise the pieces of low-power equipment 28 via the supply leads 26 in response to appropriate operation of the switches 1 8 and 20. In addition, the unit 12 indirectly controls energisation of the pieces of high-power equipment 36 in dependence on the position of the switches 1 8 and 20 by controlling operation of the actuator 34 via the second control leads 30.

The installation of the described control and distribution system in a vehicle is quick and simple and can be further facilitated by providing the first and second control leads 16 and 30 in the form of two flat, prefabricated ribbon cables with connectors at their ends. The described system also results in savings in material costs due to the considerable reduction in the total length of the high-power conductors, that is, cables 11 and 33 and leads 38, albeit at the expense of greater lengths of the remaining leads 1 6, 26 and 30 (which are of substantially lesser cross-section than the leads 11,33 and 38). The described system thus leads to a reduction in the overall manufacturing and installation cost of the control and distribution electrical power system of a vehicle.

The electronic processor unit 12 may be arranged as a self-contained unit, or incorporated either into the vehicle dashboard or the distributor unit 32.

The control and distribution system may consist of more than one distributor unit 32. For example, two units 32 may be provided, respectively arranged in proximity to the front part and to the rear part of the vehicle.

In a modified form of the control and distribution system, not illustrated in the drawings, transmission of control signals from the electronic processing unit 12 to the distributor unit 32 is effected by multiplexing the signals over a single, small cross-section, control conductor which leads to a decoding unit contained within the distributor unit 32 and connected to the actuators 34.

Illustrated diagrammatically in Figure 2 is one possible lay-out of the control and distribution system for a motor vehicle of considerable length, e.g. a coach with a rear engine.

In this lay-out, the processing unit 1 2 forms an integral part of the dashboard 50 of the vehicle, and is connected via first control leads 1 6 to switches and controls mounted on two control panels 52 of the dashboard 50, and to a direction indicator switch 54 arranged on the steering column of the vehicle.

The processing unit 12 is connected via a number of first supply leads 26 to the pieces of low-power equipment which in the present example include control warning lights 56, an instrument module 58, a speedometer 60 and a tachograph 62 all mounted on the dashboard 50.

The Figure 2 lay-out includes three distributor units 32a, 32b and 32c which are connected to the vehicle's power source via cables 33, and to the processing unit 12 via the second control leads 30.

The distributor units 32a and 32b are arranged in the front part of the vehicle and are connected via second supply leads 38, to a number of pieces of high-power equipment 36a, 36b arranged respectively within the cabin of the vehicle and within the front part of the vehicle's bodywork.

The distributor unit 32c is placed in the rear portion of the vehicle and is connected, via the second supply leads 38, to a number of pieces of high-power equipment 36c arranged in the rear portion of the vehicle's bodywork. This distributor unit 32a may be supplied directly from a single power source situated in the rear portion of the vehicle, thus effecting a considerable reduction in the length of the corresponding supply cable 33 over an arrangement where this cable 33 is run from a power source in the front portion of the vehicle.

Connection between the processing unit 12 and each distributor unit 32a, 32b and 32c is effected by means of one single control lead 30, of small cross-section, which feeds a signal decoding unit within its associated distributor unit 32a, 32b, 32c.

Claims

1. A system for the control and distribution of electrical power in a motor vehicle having both high and low-power pieces of electrical equipment which are to be energised from an electrical power source of the vehicle under the control of control switches, the system comprising an electronic processing unit arranged for electrical energisation from the vehicle's electrical power source, first control leads for connecting the processing unit to the control switches of the vehicle, first supply leads for connecting the processing unit to the pieces of low-power equipment of the vehicle, a distributor unit arranged for connection to the electrical power source, at least one second control lead connecting the distributor unit to the electronic processing unit, and second supply leads for connecting the distributor unit to the high-power pieces of equipment of the vehicle, the distribution unit being provided with a number of actuators each of which is operable to connect the power source to a respective one of the pieces of high-power equipment via a corresponding one of the second supply leads, and the processing unit being arranged to respond to operation of the control switches to directly control the energisation of the pieces of low-power equipment via the first supply leads, and to indirectly control energisation of the pieces of high-power equipment by controlling operation of the said actuators via the second control lead or leads.

2. A system according to claim 1, including at least one further distributor unit connected and arranged in a manner similar to the firstmentioned distributor unit and incorporating further actuators for controlling further pieces of high-power equipment of the vehicle under the control of the processing unit.

3. A system according to Claim 1 or Claim 2, in which the electronic processing unit consists of a microprocessor with associated logic circuits.

4. A system according to Claim 3, in which the microprocessor processing unit is of the multiple card kind, with each card carrying logic circuits associated with a respective group of vehicle functions.

5. A system according to any one of the preceding claims, in which the or each distributor unit contains safety fuses for the pieces of highpower equipment which it controls.

6. A system according to any one of the preceding claims, in which the actuators of the distributor unit or units are formed by relays.

7. A system according to any one of claims 1 to 5, in which the actuators of the distributor unit or units are formed by power transistors.

8. A system according to any one of the preceding claims, in which the electronic processing unit is connected to the or each distributor unit via a number of small crosssection second control leads contained in a single cable.

9. A system according to any one of claims 1 to 7, in which the electronic processing unit is connected to the or each distributor unit via a respective single small cross-section second control lead which feeds a decoding unit contained in the distributor unit.

10. A motor vehicle provided with an electrical power control and distribution system according to any one of the preceding claims, in which the electronic processing unit forms an integral part of the vehicle dashboard.

11. A motor vehicle provided with an electrical power control and distribution system according to any one of claims 1 to 9, in which the electronic processing unit forms an integral part of the or one of the distributor units.

12. A motor vehicle provided with an electrical power control and distribution system according to any one of claims 1 to 9, in which the electronic processing unit constitutes a selfcontained unit.

13. A rear engine coach provided with an electrical power control and distribution system according to claim 2 or to any one of claims 3 to 12 when dependent thereon, said system including a rear distributor unit for controlling the pieces of high-power equipment situated in the rear portion of the coach, and two front distributor units one of which is arranged to control pieces of high-power equipment situated in the cabin of the coach.

14. A system for the control and distribution of electrical power in a motor vehicle, the system being substantially as hereinbefore described with reference to Figure 1 or Figure 2 of the accompanying drawings.