ARRANGEMENT FOR RESPONDING TO SIGNALS FROM A NUMBER OF SENSORS AND CONTROLLING A NUMBER OF OPERATING DEVICES IN A VEHICLE, AND CONTROL UNIT

Abstract: An arrangement for responding to signals from various sensors (6) and controlling various operating devices (5) in a vehicle (1) incorporates at least two control units (A-H) which are each directed to being connected to a subset of said sensors and operating devices and to receiving signals from the subset of sensors and sending control signals to the subset of operating devices. Each control unit (A-H) incorporates elements which are substantially identical with those of each of the other control units, and the control units are so designed as to be mutually interchangeable. Each control unit (A-H) may also incorporate not only a memory device with a number of control programmes which are designed to respond to the various sensors (6) and to control the various operating devices (5) but also a means which is directed to activating the subset of the control programmes which is designed to receive signals from the subset of sensors of the relevant control unit and send control signals to the subset of operating devices of that control unit.

Description: Arrangement for responding to signals from a number of sensors and controlling a number of operating devices in a vehicle, and control unit Background to the invention and state of the art The present invention relates to an arrangement in accordance with the preamble to patent claim 1 and a control unit in accordance with the preamble to patent claim 12. Conventional electrical systems for vehicles incorporate a large number of electrical conductors running between various vehicle components, i.e. in principle a separate electrical conductor for, to a large extent, each signal or electrical voltage to be transmitted between two vehicle components. This means extensive cable laying with large bunches of cables extending in various directions in the vehicle. Moreover, vehicle models with different equipment variants require different cable laying, which leads to higher production costs. The growing amount of electrical extra equipment in modern vehicles has therefore resulted in exacerbation of this problem when using conventional cable laying. This problem is addressed by using electronic control systems, so-called multiplex systems, based on a common signal line which runs in a single loop in the vehicle, and on individual vehicle components being connected to this signal line in the vicinity of their respective positions in the vehicle. These connections are made by means of a control unit or a so-called node which processes incoming sensor signals and supplies outgoing control signals to the components concerned. The fact that a signal line can be used for controlling two or more vehicle components means that the total number of cables can be reduced. Such modern electrical control systems for motor vehicles do incorporate, however, a large number of different control units or nodes, particularly in more complex and larger vehicles such as buses, which have a great deal of extra equipment, e.g. for controlling the opening and closing of the various doors, for communication between driver and passengers, etc. These control units or nodes are specific to the various functions which they are adapted to controlling. This means that a large number of different types of control units have to be developed and manufactured for different vehicles and for different variants of the same vehicle. It also means that correspondingly large numbers of different control units have to be stocked by each individual workshop in order to be able to meet customer demand for a high level of service. Examples of various electrical control systems are referred to in the documents quoted below. US-A-3 544 803 refers to an electrical distribution and control system for motor vehicles, incorporating a power distribution line and a signal distribution line which are arranged parallel with one another. To these lines are connected detector stations and various control and function stations for controlling equivalent vehicle functions such as lamps, windscreen wipers, etc. US-A-3 864 578 refers to a multiplex system for controlling various vehicle components which incorporates an encoding device which on the basis of the position of a sensor generates a time signal and a code signal, a decoding device arranged at a distance from the encoding device to deliver an output signal in response to said code signal, and a relay device delivering a modulating signal to relevant components which respond to said output signal. SE-B-458 886 refers to a system for transmitting information between various components of a vehicle. The system incorporates a monitor node and a number of transmission nodes which are connected to a bus for communication between nodes. The purpose of the transmission nodes is to receive information from connected vehicle components, to transmit to one another, via the bus, component information arising from connected vehicle components, and to supply connected vehicle components with component information which they require for them to be able to function. Summary of the invention The object of the present invention is to eliminate the aforesaid problem and provide an electrical control system for vehicles which requires relatively few different kinds of articles and leads to simplified manufacture and stockholding. A further object is simplified management of servicing as compared with systems available at present, a particular aim being to be able to replace control units in a very simple and reliable manner. This object is achieved by the arrangement indicated in the introduction being designed according to the features indicated in the characterising part of patent claim 1. Vehicle manufacture and servicing are thus facilitated because fewer articles need to be manufactured and held in stock. The present invention is thus based on the realisation that it is possible to create a complex and comprehensive electrical vehicle control system composed of a large number of substantially identical control units. According to one embodiment of the invention, each control unit incorporates not only a memory device with a number of control programmes which are designed to respond to the various sensors and control the various operating devices, but also a means which is directed to activating the subset of control programmes which is designed to receive sensor signals from the subset of sensors of the relevant control unit and to send control signals to the subset of operating devices of the relevant control unit. Such a means of activation makes it easy to adapt each individual control unit to relevant specific vehicle functions. It also results in only the memory capacity and software of control units having to be overdimensioned as compared with control units being only manufactured to cope with relevant specific vehicle functions. Such memory capacity is now available at very favourable cost. The software has in any case to be produced and the present invention thus results in it only being necessary for it to be copied to a number of control units, an operation involving only negligible further cost. At the same time, said memory devices may incorporate a permanently programmed section in which said number of control programmes are preprogrammed. According to a further embodiment of the invention, said means of activation is directed to activating said subset of control programmes at the time when the control units are fitted in the vehicle. It is advantageous to carry out adaptation of the control units to relevant specific vehicle functions at that stage. This facilitates manufacture and, above all, the replacement of defective control units. Said means of activation may with advantage incorporate a set-up of code contacts connected in such a way that activation of the relevant control programmes is by connection of a combination of these code contacts. At the same time, each control unit may incorporate a connector which incorporates said set-up of code contacts and which is directed to being connected to a corresponding connector in the vehicle, said connection being effected at the time of the connection of the connectors to one another. This makes adaptation very easy and ensures that it involves no mistakes, since the design of the vehicle's connectors determines which of the functions of the control unit are activated. It is also advantageous for the connectors of each control unit to incorporate a number of connection contacts for signals coming in from sensors and signals going out to operating devices. The connector may thus incorporate all the contacts, and the fitting and adaptation of a control unit may be carried out by simply connecting its connectors. According to a further embodiment of the invention, each control unit incorporates a memory device with a programmable memory section in which parameters specific to the vehicle are stored. At the same time, each control unit may be adapted to make the transmission of said vehicle- specific parameters to another control unit possible, e.g. at the time of fitting a new control unit in the vehicle. This makes it possible for all vehicle-specific parameters to be loaded automatically into all the control units when a new control unit is inserted in an existing arrangement according to the invention. This means that the information needed for an individual vehicle is stored in each control unit and that when a control unit is replaced this information can be transferred to the new control unit without having to proceed circuitously via externally stored data, e.g. from a diskette. Such vehicle-specific parameters can be used to adapt control units to different variants of the same vehicle, e.g. with different types of extra equipment. According to a further embodiment of the invention, the arrangement incorporates a transmission line connecting the control units to one another and directed to transmitting signals between control units. This makes it possible for the control units to form part of a so-called multiplex system by being arranged to enable a sensor signal received by a control unit to be transmitted from that control unit to another in order to control a component connected to the latter. The object stated above is also achieved by the control unit indicated in the introduction being designed with the features indicated in the characterising part of patent claim 12. Advantageous embodiments of such a control unit are indicated in dependent claims 13 to 18. Brief description of the drawings The invention will now be explained in more detail on the basis of various embodiments with reference to the attached drawings, which are as follows: Fig.l shows a schematic block diagram of an arrangement according to the present invention, and Fig.2 shows a schematic block diagram of a control unit according to the present invention. Detailed description of various embodiments Fig.l shows an arrangement for controlling various functions of a schematically depicted vehicle 1. In the embodiment here described the vehicle is a bus but the present invention is of course also applicable to other types of vehicle such as trucks, tanker vehicles, passenger cars etc. The arrangement incorporates a schematically depicted electrical system with a power source in the form of a vehicle battery 2 connected via a power line 3 to each of eight control units A-H. The latter are connected to a common transmission line 4 arranged to transmit signals between them. Each control unit A-H is further connected to a number of operating devices 5 and a number of sensors 6. The various operating devices 5 may incorporate all conceivable active and passive functions in a vehicle, which may be activated by electric current directly or via a relay, a servomotor or an actuator, and examples include various lighting devices such as brake lamps, rear lamps, flashers, interior lighting, various warning lamps for the driver, etc. The operating devices 5 may also include analogue and digital indicating devices, windscreen wipers, door openers, horns, etc. The sensors 6 may include every conceivable type of sensor for all the operating devices 5 of the vehicle 1. The sensors 6 may thus include, for example, temperature sensors (e.g. for coolants) , brake lamp contacts, various control devices such as flasher controls, lamp switches, photoelectric cells for counting the number of passengers, door opening buttons, etc. It should be noted that all the various types of operating devices 5 referred to are marked in the same manner in Fig.l, as also all the various types of sensor 6 referred to. In the embodiment depicted in Fig.l, control units D and E are situated in the front part of the vehicle 1 to serve the various sensors 6 and operating devices 5 used by the driver. Fig.2 shows schematically the structure of one of the control units A-H depicted in Fig.l according to the present invention. The control units A-H are substantially identical but for the sake of simplicity the one depicted in Fig.2 is control unit A, which receives electric current from the power line 3 via the schematically depicted input 7. Control unit A incorporates a processing device in the form of a processor 8 which is connected to a memory device with a permanently programmed memory 9 (a so-called readonly or ROM memory) and with a programmable memory 10, preferably a so-called PROM memory. Control unit A further incorporates a series channel device 11 which is connected to the processor 8 and which can be used to connect the control unit to an undepicted external computer via the connection pins 12. The processor is also connected to a communication port 13 which can be used to connect it to the other control units B-H via the connection pins 14. The processor 8 is further connected to an input device 15 with a number of connection pins 16 (e.g. four to twenty) and an output device 17 with a number of connection pins 18 (e.g. four to twenty) . The processor 8 is thus connected to the sensors 6 of control unit A via the connection pins 16 and the input device 15 and to the operating devices 5 of control unit A via the connection pins 18 and the output device 17. Control unit A further incorporates an activating or encoding device 19 with four connection pins 20. The connection pins 12, 14, 16, 18 and 20 are contained in a connector 21 which is directed to being connected to a corresponding connector 22 in the vehicle 1. The corresponding connector is connected to the power source 2 , to earth, to the transmission line 4, to the various operating devices 5 and to the various sensors 6. The permanently programmed memory 9 of control units A-H contains a number of preprogrammed control programmes each designed to respond to sensor signals from one of the sensors 6 and to control one or more operating devices 5. In order, for example, to adapt control unit A to the operating devices 5 and sensors 6 which it is intended to serve, the activating or encoding device 19 is designed, when the connectors 21 and 22 are connected to one another during the fitting of control unit A in the vehicle 1, to activate a subset of the preprogrammed control programmes in the memory 9, and more specifically the control programmes designed to receive signals from the sensors 6 connected to control unit A and to send control signals to the operating devices 6 connected to control unit A. This is achieved by connecting a particular combination of the connection pins 20, e.g. by connecting them to earth. The memory 9 can thus be programmed so that relevant tasks of control unit A can be performed by the connection pins 21 and 22 being connected to one another. Parameters specific to the vehicle are stored in the programmable memory 10. They are contained in a parameter list which includes information on the number of control units and how the various parameters for the operating devices of the vehicle 1 have to be set. The parameter list thus contains all the specific information for each individual vehicle 1, i.e. the particular vehicle variant. It is possible, for example, that a certain function which exists in the vehicle 1 will not be used, that the vehicle 1 is equipped with a special extra function, etc. These vehicle-specific parameters are thus loaded into the programmable memory 10 of all the control units A-H. The various control programmes activated in the permanent memory 9 can then call up their respective parameters from the memory 10 via the processor 8. Each control unit A-H is also directed to making it possible to transmit said vehicle-specific parameters to another control unit A-H via the communication port 13. This can, for example, take place automatically when a new control unit is being fitted in the vehicle 1. This facilitates the replacement of a defective control unit in that a new one with no vehicle- specific parameters at all is fitted in the vehicle 1 and will then be automatically adapted to the latter by the arrangement according to the invention. In addition to the fact that this means that only one type of control unit is required for a large number of different vehicles, the risk of errors at the fitting stage is very substantially reduced. Control units A-H are directed to operating according to the so-called multiplex principle, which means inter alia that a sensor signal received by a control unit (e.g. control unit A) can be transmitted via the transmission line 4 to another control unit (e.g. control unit B) in order to control an operating device 6 connected to the latter. An example which may be mentioned in this respect is that one of the sensors 6 of control unit A may take the form of a contact device arranged to be activated by a passenger who wants the bus to halt at the next stop, which involves a sensor signal being received by control unit A and passed on to the transmission line 4. The control unit (in this case control unit D) which is connected to the operating device 5 of the particular sensor 6 (i.e. an indicating lamp which directs the driver to halt at the next stop) receives and processes that sensor signal and emits a control signal, e.g. in the form of a voltage which lights up the indicating lamp. In more detail, the arrangement can operate so that a sensor signal received by control unit A is passed on by the processor 8 via the communication port 13 to the transmission line 4. All the other control units B-H detect the signal and it will be received and processed by the processor/processors 8 of the control unit/units B-H which operates/operate the particular operating device/devices 5. The processor 8 of any relevant control unit B-H will thus execute the control programme which is stored in its permanent memory 9. The electrical system of the vehicle 1 can be controlled by means of an external computer connected via the series channel device 11 of any of control units B- H. Such an external computer can also be used to supply new vehicle parameters or amend existing ones. Control units A-H all have the same status in the arrangement according to the invention, i.e. all the control units can receive and pass on sensor signals, all the control units can process sensor signals and all the control units can receive and transmit vehicle-specific information from another control unit or an external computer. The present invention is not limited to the embodiments referred to above but may be varied and modified within the scope of the patent claims below. The embodiments referred to incorporate eight control units. It is of course clear that the arrangement according to the invention can also be used with fewer (e.g. only two) or with more control units. The activating or encoding device 19 referred to may in an alternative embodiment take the form of a setting device which at the time of fitting control units A-H is set by the fitter at a point corresponding to the location of the control unit in the vehicle 1.

Claims: Claims 1. Arrangement for responding to signals from various sensors (6) and controlling various operating devices (5) in a vehicle (1) , and incorporating at least two control units (A-H) which are each directed to being connected to a subset of said sensors (6) and a subset of said operating devices (5) and to receive signals from said subset of sensors and send control signals to said subset of operating devices, characterised in that each control unit (A-H) incorporates elements essentially identical to those of each of the other control units and that the control units (A-H) are designed in such a way as to be mutually interchangeable. 2. Arrangement according to claim 1, characterised in that each control unit (A-H) incorporates not only a memory device (9) with a number of control programmes which are designed to respond to the various sensors and to control the various operating devices (5) but also a means (19) which is directed to activating the subset of the control programmes which is designed to receive signals from the subset of sensors (6) of the relevant control unit and to send control signals to the subset of operating devices (5) of that control unit. 3. Arrangement according to claim 2 , characterised in that said memory device (9) contains a permanently programmed section in which said number of control programmes is preprogrammed. 4. Arrangement according to any one of the foregoing claims, characterised in that said activating means (19) is directed to activating said subset of the control programmes at the time when the control units (A-H) are being fitted in the vehicle (1) . 5. Arrangement according to any one of the foregoing claims, characterised in that said activating means (19) incorporates a set-up of code contacts (20) connected in such a way that activation of the relevant control programmes is by connection of a combination of these code contacts. 6. Arrangement according to claim 5, characterised in that each control unit (A-H) incorporates a connector (21) which contains said set-up of code contacts (20) and which is directed to being connected to a corresponding connector (22) in the vehicle (1) , which connection is made by the connectors (21,22) being connected to one another. 7. Arrangement according to claim 6, characterised in that the connector (21) of each control unit (A-H) incorporates a number of connection contacts (16,18) for incoming signals from the sensors (6) and outgoing signals to the operating devices (5) . 8. Arrangement according to any one of the foregoing claims, characterised in that each control unit (A-H) incorporates a memory device (10) with a programmable memory section in which vehicle-specific parameters are stored. 9. Arrangement according to claim 8, characterised in that each control unit (A-H) is directed to making it possible for said vehicle-specific parameters to be transmitted to another control unit, e.g. when the vehicle (1) is being fitted with a new control unit. 10. Arrangement according to any of the foregoing claims, characterised in that a transmission line (4) connects the control units (A-H) to one another and is directed to transmitting signals between the control units. 11. Arrangement according to claim 10, characterised in that the control units (A-H) are arranged to make it possible to transmit a sensor signal received by a control unit from the latter to another control unit in order to control an operating device (5) which is connected to that other control unit. 12. Control unit which responds to signals from various sensors (6) and controls various operating devices (5) in a vehicle (1) and which incorporates a memory device (9) with a number of control programmes which are designed to respond to the various sensors and to control the various operating devices, and with a processing device (8) which is directed to executing said control programmes, characterised by a means (19) which is designed to activate a subset of said number of control programmes which relates to the sensors (6) and operating devices (5) to which the control unit is intended to be connected. 13. Control unit according to claim 12, characterised in that said memory device (9) incorporates a permanently programmed section in which said number of control programmes are preprogrammed. 14. Control unit according to either of claims 12 and 13, characterised in that said activating means (19) is designed to activate said subset of the control programmes when the vehicle (1) is being fitted with the control units (A-H) . 15. Control unit according to any one of claims 12 to 14, characterised in that said activating means (19) incorporates a set-up of code contacts (20) connected in such a way that activation of the control programmes concerned is by connection of a combination of these code contacts. 16. Control unit according to claim 15, characterised in that the connector (21) which incorporates said set-up of code contacts (20) is directed to being connected to a corresponding connector (22) in the vehicle, said connection being brought about by connecting the connectors (21,22) to one another. 17. Control unit according to claim 16, characterised in that the connector (21) incorporates a number of connection pins (16,18) for incoming signals from the sensors (6) and outgoing signals to the operating devices (5) . 18. Control unit according to any one of claims 12 to 17 , characterised in that said memory device (10) incorporates a programmable memory section in which vehicle-specific parameters are stored.

Inventors: CROMNOW CHRISTER, LYBERGER RICKARD, CROMNOW, CHRISTER, LYBERGER, RICKARD
Applicants: SCANIA CV ABP, SCANIA CV AKTIEBOLAG (PUBL)
Application year: 1997
Main classification: B60R16
IPC codes: B60R16