FR2694848A1 - Centralised control device for automotive vehicle electrical accessories - has central voltage feed control unit connected to each accessory unit by four conductors, with each accessory unit having coder passing messages to central control unit - Google Patents

Abstract

The central voltage control device (1) is for controlling electric accessories (11-14) having feed lines to line circuits passing around the car. Each accessory has a coding unit (13) which passes coded (3,4) messages along a pair of transmission wires (40,41) to a central voltage feed control (1). Each accessory is also supplied with two power supply conductors. The central voltage feed unit has a switch which switches ON or OFF voltages to operate the different accessories. To operate the coding, an appropriate pushbutton (73) is pressed, activating the coding unit (71) which sends out two level digital codes appropriate to the unit to be activated. The code must be transmitted several times before it is activated. The coding unit can also operate relays (72) directly as an alternative. USE/ADVANTAGE - For controlling electrical ancillaries of vehicle such as electric window winders, door locking, air conditioning and lighting systems. Simple structure network with high reliability.

Description

 The present invention relates to the centralized control of the various electrical accessories fitted to a motor vehicle such as door locking devices, window regulators, lighting, air conditioning devices, etc.

 The number of accessories in a motor vehicle, which contributes to passenger safety and comfort, is tending to increase significantly; this leads to wiring operations which increase the cost price both with regard to the material used, essentially electrical conductors, and the labor time necessary for these wiring operations. Wiring harnesses can also present congestion problems.

 Centralized control systems have been designed which comprise a central control unit generally arranged at the dashboard and which is connected to units arranged at the level of an accessory, such as a window regulator, a door lock. , a rear-view mirror. These accessory units comprise at least one electric actuator such as a motor or a relay, the actuation of which can be controlled either locally at the level of the unit or by an order issued by the central control unit.

 Some accessories may include "intelligent" control units which include a processor which can react to information from other accessory units so as to perform a function correlated with a function performed in another accessory. For example, a window regulator may respond to a door lock order to raise the window.

 The connection between the central control unit and the accessory units is made in the middle of lines transmitting both the power supply and order or information messages. To limit the number of conductors as much as possible, multiplexing systems have been proposed which are relatively complex since it is necessary to avoid any untimely operation under the influence of the numerous parasites which exist in a motor vehicle.

 The present invention proposes to provide a centralized control device for electrical accessories for the equipment of a motor vehicle, the structure of which is simple and which however makes it possible to obtain high operating reliability.

 To this end, the subject of the present invention is a device for centralized control of the electrical accessories of equipment of a motor vehicle comprising a central control unit and accessory units each performing at least one function, characterized in that the central control unit is connected to each accessory unit by a line comprising four conductors, including two message transmission conductors and two supply conductors, the central control unit sends, cyclically, over the transmission conductors of messages, pulse trains of the same width comprising at least one pulse corresponding to a message representative of a function of an accessory unit, each accessory unit comprises a coding and decoding module connected to said conductor of transmission of orders, each message is materialized by a modification of the corresponding pulse, each unit module d accessory comprises means for detecting a modification of at least one pulse and means for modifying the pulses corresponding to the messages of the functions performed by the accessory unit considered, and the central unit comprises means for detecting modifying any pulse in order to detect the messages sent by the accessory units and means for modifying any pulse in order to send a message to at least one accessory unit.

 The invention makes it possible to use control beams comprising only three conductors; moreover, each message is simply translated by a pulse modification, each pulse corresponding to a given message which is therefore identified by the rank of the pulse considered in the pulse train. As a result, this coding system is much less sensitive to spurious signals that can be created in a motor vehicle.

 Each accessory unit can only modify the pulses corresponding to the functions it performs; it can obviously detect the modifications of the impulses corresponding to the messages of functions which it carries out but it can also detect the modifications of impulses corresponding to messages concerning other units, which makes it possible to carry out "intelligent" accessory units .

 According to another characteristic of the invention, the message pulses are grouped into several ordered groups, the message pulses corresponding to urgent messages are grouped into at least one group of urgent message pulses, the groups of message pulses being urgent first, each group being preceded, in the pulse trains, by a group head pulse which does not correspond to a message and whose amplitude is different from that of the message pulses, the modification of a message pulse of a group leading to the modification of the head pulse of this group, the central unit controls the sending, in a cyclic manner, on the message transmission conductors, of trains of pulses comprising only pulses of the group head ordered, comprising at least the group head pulses of urgent messages, for each pulse train, the central unit scans by the means for detecting a pulse modification, the head pulses of group of urgent messages and the last pulse of group head of non-urgent messages, and, in the event of detection of the modification of a pulse of head of group, the central unit controls the sending, following this modified group head pulse, the message pulses of the group considered and scans the message pulses to detect a modified pulse.

 This arrangement makes it possible to execute, as a priority and with a short response time, urgent orders relating, for example, to the functions for moving movable elements such as windows, mirrors, etc.

 According to yet another characteristic of the invention, the transmission of the pulse trains by the central unit is interrupted after a predetermined time following the detection of a message, at least one accessory unit comprises a device generator of a reactivation signal on the two message transmission conductors and the central unit includes a device for detecting said reactivation signal so that the emission of a reactivation signal results in the retransmission of the pulse trains on the transmission conductors.

 Thanks to this arrangement, it is possible to limit as much as possible the electrical consumption of the accessories of a vehicle, in particular when the latter is not used. In the latter case, an unlocking order of the doors which acts on the units corresponding to the door locks causes the emission of a reactivation signal to bring the central unit from the standby state to the state of work.

 According to a first embodiment of the invention, each accessory unit includes actuation relays controlled by the decoding means of its module. In this case, the orders concerning a unit are carried out by actuation of the relays which it contains.

 The control device according to the invention can comprise several independent lines with four conductors, the central unit comprising detection and modification means for each line.

 This arrangement makes it possible to avoid oversizing the transmission voltage supply conductors.

 Advantageously, the coding and decoding modules of the accessory units are self-powered at least partially by the pulses of the pulse trains.

Other characteristics and advantages of the invention will emerge from the description which follows, made with reference to the appended drawings in which
- Figures 1 to 3 show different possibilities of connection between the central control unit and the accessory units
- Figure 4 is a diagram showing details of embodiment of the central control unit and an accessory unit
- Figure 5 is a view showing the pulse trains
- Figure 6 is an embodiment of a device for modifying pulses by an accessory unit
- Figure 7 shows an example of configuration of a centralized control system of all the accessories of a motor vehicle; and
- Figure 8 illustrates an alternative embodiment of the invention.

 FIGS. 1, 2 and 3 represent three possibilities of making the connection between a central control unit 1 and accessory control units 11, 12, 13 and 14.

 In the embodiment of FIG. 1, the central unit 1 is connected to the different accessory units 11 to 13 by a line with four conductors constituting a sort of bus line 2 on which the different accessory units are connected in parallel.

 In the arrangement of FIG. 2, each accessory unit comprises a specialized connection line 110, 120 or 130 so as to constitute a star network.

 Finally, as shown in FIG. 3, there can be a combination of these structures, namely a tree-like structure comprising two parallel bus lines 3 and 4 each supplying two accessory units 11 and 12 on the one hand and 13 and 14 on the other hand.

 ~ Figure 4 shows the central control unit 1 on which are connected two parallel bus lines 3 and 4 and the accessory unit 13 is shown in detail.

 Each network comprises two specialized conductors 30 and 31, respectively 40 and 41, which are used for the transmission of messages and two conductors 32 and 33, on the one hand, 42 and 43, on the other hand, which are permanently connected, at the central control unit 1, respectively at the positive and negative terminals of the power source.

 FIG. 5 represents a first embodiment of the invention, a pulse train emitted by the central control unit 1. This pulse train comprises a first pulse 51 which defines the start of the pulse train and which is wider than the pulses corresponding to the different messages. This synchronization pulse 51 is followed by message pulses 52. The number of message pulses which is the same for each train of pulses is at least equal to the maximum number of messages to be transmitted; unassigned pulses can be provided in reserve for optional accessories for example.

 The message pulses 52 for example have a duration of 0.15 ms, they are separated by durations equal to 0.15 ms and the synchronization pulse 51 can for example have a duration of 3 ms. The transmission frequency of the pulse trains is for example 3 kHz.

 We see that the rank 5 pulse has been modified; in the example shown, the modification consists in reducing the level of this fifth pulse. This modification of the fifth pulse constitutes a message which will be decoded by the accessory unit to which this message corresponds, which can for example be a message to lower a window; this message can also be detected by other accessory units which are not directly concerned by the message but which use it as information which can trigger an activation of the accessory unit. This is the case of so-called "intelligent" units which can detect an order message concerning another accessory unit and order the execution of a function linked to this order.

 Each accessory unit can be controlled by the central control unit or locally by means of control buttons for example. Each time a function is directly controlled at an accessory, the accessory unit generates a message on the message transmission conductor by modifying the corresponding pulse, for example by means of a transistor. 70.

 Thus, any realization of a function given in one of the accessories results in the sending of a message on the specialized conductors of transmission of messages by modification of the impulse concerned.

 Each accessory unit naturally includes a module for decoding the different messages which is at least sensitive to all the messages which concern it.

 In the diagram of FIG. 4, some of the elements of the central control unit 1 are shown schematically, which essentially comprises a processor 61. The means for modifying a pulse are for example constituted by a transistor 62 operating in light switch. The means for detecting the modification of a pulse are produced for example by means of a comparator 64 which detects the variation in current on the message transmission conductors.

A transistor 63 is provided to generate the pulses.

 The accessory unit 13 comprises a coding and decoding module 71 which controls relays 72 which supply the various actuators of the unit.

 The coding 70 and decoding module 71 is connected to the message transmission line 41 and is self-powered at least partially by the pulses of the pulse trains.

 The accessory unit 13 also includes direct control buttons which act, for example, on contactors 73, each contactor corresponding to a particular function. When one of these contactors is actuated, the corresponding function is carried out and, simultaneously, the emission of a corresponding message is commanded by modification of the pulse considered in the pulse trains which circulate on the conductor 41, by means, for example, of transistor 70.

 The accessory unit 13 can also include a processor 74 which receives messages decoded by the module 71 and which can control the functions specific to the unit, for example by acting on the relays 72.

 Such an accessory unit equipped with a processor constitutes an "intelligent" accessory unit which can control its actuators without issuing an order from the central control unit.

 In this case, if the processor receives a message from the decoding module 71 which relates to a function of another accessory which is linked to a function of the accessory unit considered, the processor first of all performs a consistency check. , for example by checking the presence of the message on several pulse trains so as to avoid untimely commands.

If this check is positive, the processor gives the order concerning the function considered to the accessory unit which it controls.

 As indicated above, this can apply in the case of a window regulator which reacts to a door locking command to raise the window which it controls.

 This correlation with the messages sent by the accessory units is also carried out at the level of the central unit which also includes a processor.

In this case, for example if the window regulator accessory unit does not include a processor, it is the central control unit which will perform the correlation and the consistency check and then send a message to the other units concerned by the order issued by an accessory unit.

 The central control unit can also manage the various transmission lines so as to avoid excessive consumption.

Thus, for example, the centralized control unit can interrupt the control of a high-consumption accessory, such as a window defrost, to have a priority function performed.

 FIG. 6 represents an embodiment of a coding device of an accessory unit, that is to say of a device making it possible to modify a pulse of each of the trains of pulses circulating on the conductors of transmission of messages. This device consists essentially of a counter 81 which is self-powered from the power transmission line by means of a diode 82 associated with a filtering capacitor 83. The pulses of each train of pulses are sent to input 84 of counter 81.

 On each of the outputs of this counter 81, the rank of which corresponds to the messages that can be sent by the unit considered, a circuit is connected allowing the voltage of the pulse considered to drop; this circuit consists of one of the contactors 73 which is connected in series with a diode 85 and controls the base of a transistor 86 connected between the message transmission conductor and a return conductor constituted for example by ground. When one of the contactors 73 is pressed, during the passage of the corresponding pulse, the transistor 86 is activated which causes the passage of a current through a load resistor 87 which results in a weakening of the level of the corresponding pulse.

 FIG. 7 represents an exemplary embodiment of a centralized control according to the invention. The central control unit 1 is connected in a tree-like arrangement by lines with three conductors to the various accessories of the vehicle grouped together at each of the doors and of the rear window of the vehicle.

 Each assembly comprises a lock 91, all of the locks being able to be controlled centrally, and individual lighting 92. Each of the doors comprises a window lifting device 93. The driver's seat may include a control console 94, a another central control console 95 may be provided. At the rear opening, there is a defrosting device 96 and a window regulator 97.

 The front doors have an exterior mirror control 98.

 FIG. 8 illustrates an alternative embodiment of the invention according to which the message pulses are grouped into several groups, each group being preceded, in the pulse trains, by a group head pulse which does not correspond to a message and the amplitude of which is different from that of the message pulses.

In the example shown, there are one hundred message pulses which are grouped into ten groups A to
J each comprising ten pulses and which, when emitted in the pulse trains, are preceded by a group head pulse a to j.

 The number of message pulses for each group can be different for each group. As will be seen below, it is also possible to modify the number of message pulses of a group by acting on the operating program of the central unit.

 According to the invention, when the coding and decoding module of an accessory unit is controlled to modify a message pulse, it also simultaneously modifies the corresponding group head pulse. Thus, when in one group of pulses one of the pulses has been modified, the group head pulse is also modified.

 According to another characteristic of the invention, the central unit is programmed to send only the group head pulses in the pulse trains. If an accessory unit sends a message by modifying a message pulse and the group head pulse considered, when the central unit sends the group head pulse considered, this is immediately modified by the module coding and decoding of the accessory unit considered. This is immediately detected by the central unit which immediately orders the sending, following the group head pulse considered, of all of the group message pulses. In this way, the pulse trains of each cycle comprise only unmodified group head pulses and the modified group head pulses followed by the corresponding message pulses.

 This has the consequence that the length of the pulse trains is very greatly reduced, which makes it possible to greatly reduce the response time to a message, for example of order.

 The pulses concerning orders to be carried out without delay are, for example, grouped into the first three groups A, B and C. These priority orders are, for example, orders for controlling the movement of a window or a rear view mirror; in fact it is important, for example when the driver adjusts his mirror, that the movement of the mirror stops as soon as the driver releases the control button. This allows to obtain a precise positioning of the mirror or a window regulator for example.

 To further limit the length of the pulse trains sent to the message transmission conductors, and, consequently, the maximum time that can elapse between the emission or the end of an order given by a user and taking into account account of this order by the centralized control device, only the head group priority message pulses are transmitted continuously in each pulse train; the non-urgent message group head pulses are transmitted cyclically according to a cycle of successive wave trains.

 Each pulse train in a cycle always includes all the group head pulses from the urgent message groups; it can include one or more non-urgent message group head pulses.

 As can be seen in FIG. 8, the first pulse train comprises the head group pulses of urgent messages a, b and c and the first group head pulse of non-urgent messages. The next pulse train obviously always includes the group heads of the urgent message pulses a, b and c and the first two group pulses of the non-urgent message group, and so on up to the seventh pulse train. which includes all of the group head pulses. In other words, each pulse train comprises the head pulses of group of urgent messages and the first pulses of group head of non-urgent messages, a varying between 1 and the number n of groups of non-urgent messages, 7 in the example shown.

 It is possible to envisage other pulse train cycles, each one always comprising all the head group pulses of urgent messages. One can for example provide a pulse train comprising only the head group pulses of urgent messages.

The other cycles can include a variable number of non-urgent message group head pulses, the group head pulses always appearing in their predetermined order.

 According to another characteristic of the invention, the central control unit 1 cites, in each pulse train, the head pulses of group of urgent messages and the last head pulse of groups of non-urgent messages.

 In the event that one of the group head pulses is modified, the central unit then commands the sending, following this modified group head pulse, of corresponding message pulses and it scans these pulses of messages to detect the pulse of the messages which is modified in order to command the actions corresponding to the message concerned.

 In this way, the length of the pulse trains is particularly reduced, which makes it possible to further shorten the duration of a cycle, all the group head pulses having been scanned by the central unit during the complete cycle.

 In FIG. 8, the second train of pulses of a cycle is shown. It firstly comprises a pulse train start pulse 51, the group head pulses a, b and c, the set of group C message pulses, the group head pulses d and e and the set of message pulses from group e.

 It can be seen that the group heads have a different amplitude from the message pulses 52. Furthermore, as indicated above, each modified group head pulse is followed by all of the corresponding message pulses. Thus, for example, the pulse C2 of group C being modified, the pulse of head of group c is modified and all of the message pulses C1 to C10 are sent in this train of pulses, the same is true for group E where the modification of the message pulse El resulted in the modification of the group head pulse e and, consequently, in accordance with the operating programs of the central unit, the transmission of all the message pulses E1 to E10.

 In this embodiment of FIG. 8, it can be seen that the modification of the message or group head pulses consists of a change in the level of the rear part of the pulse, the rising edge of which is preserved. Thanks to this type of modification, the structure of the logic circuits of the coding and decoding modules, which work on the rising edges of the pulses, are simplified, since there is no need to adapt the detection levels.

 Therefore, the rising edge of the pulses has a nominal level which makes it possible to stabilize the coding register circuits and the rear part of each pulse can have a modified level which can vary between a high threshold and an acceptable low threshold.

 It can also be seen that in this example, the modified level of the rear part of the pulse is the same for the group head pulses and for the message pulses. This also makes it possible to simplify the logic decoding circuits. Advantageously, this modified level of the trailing edge of the pulses is not zero.

 Thanks to this variant, the response time for urgent orders is greatly reduced, which is, in the example shown, to a maximum of 10 ms for a pulse frequency of the order of 4 to 5 kHz. For non-urgent orders, the maximum response time corresponds to the sum of the seven pulse trains of a cycle, i.e. the response time will be much less than 2 s. This value is still compatible for orders that do not require a short response time, such as for example locking the child door security.

 As can be seen in FIG. 8, the group head pulses have a different amplitude from the message pulses 52.

In Figure 8, a full cycle of pulse trains is shown. The first pulse train comprises the first four group head pulses, namely the group head pulses of urgent messages a, b and c and the group head pulse of the first group of non-urgent messages d. The next pulse train always has the three head pulses of the urgent message group and the first two head pulses of the non-emergency message group d and e and so on, the seventh pulse train having the head pulses group a to d
It can be seen that the invention makes it possible to analyze a centralized control device for the accessories of a motor vehicle, the structure of which is simple and which is not very sensitive to interference since the messages are materialized by the modification of an impulse.

 Furthermore, the number of conductors required is greatly reduced, which makes it possible to reduce the manufacturing costs relating to the wiring accordingly.

If, with the necessary protections, the conductor 40 is used as a negative supply conductor, the number of conductors used is reduced to three.

 In an exemplary embodiment, the message pulses are grouped into eight groups; the first group includes the control commands for the front windows and the right rear window, which corresponds to nine message pulses, three per window, the second group contains the control pulses for the left rear window of the exterior mirror and the general safety of window regulators, namely eight pulses. These first two groups concern orders or messages that can be sent by the driver on a control console that is available to him. A third group concerns the controls available to passengers: the rear window and front right window controls, namely nine pulses.

 The fourth group of messages concerns the door switches for right and left locking as well as the control of the safety of child doors and the switching command between the right and left mirrors; this fourth train of pulses has seven pulses. The fifth train of pulses includes the switching messages for right or left mirror, engine contact, accessory contact, deployment lighting or folding of the mirrors and defrosting, namely eight pulses. The sixth group has ten imp

 It can be seen that the invention makes it possible to analyze a centralized control device for accessories of a motor vehicle, the structure of which is simple and which is not very sensitive to interference since the messages are materialized by the modification of an impulse.

 Furthermore, the number of conductors required is greatly reduced, which makes it possible to reduce the manufacturing costs relating to the wiring accordingly.

If the mass of the vehicle is used as a negative supply conductor, the number of conductors used is reduced to three.

Claims (8)

 1. Device for centralized control of electrical accessories for the equipment of a motor vehicle comprising a central control unit (1) and accessory units (11-14) each performing at least one function, characterized in that the central control unit (1) is connected to each accessory unit by a network (2-4,11,120,130) comprising four conductors, of which two conductors (30,31; 40,41) for message transmission and two conductors of supply (32,33; 42, 43), in that the central control unit (1) sends, acyclically, on the message transmission conductors (30,31; 40,41), trains of pulses of the same width, in that each message is associated with a pulse of given rank, the transmission of a message being materialized by the modification of the pulse which is assigned to it, in that each accessory unit (1114 ) comprises a coding and decoding module (71) connected to said conductors (30,31; 40,41 ) for transmitting messages and comprising means for detecting a modification of at least one pulse and means (86) for modification (81, 73) of the pulses corresponding to the messages of the functions performed by the accessory unit considered , and in that the central unit comprises means (64) for detecting the modification of any pulse in order to detect the messages sent by the accessory units and means (62) for modifying a pulse to send a message to at least one accessory unit.  2. Centralized control device according to claim 1, characterized in that the message pulses are grouped into several ordered groups, in that the message pulses corresponding to urgent messages are grouped into at least one group of message pulses urgent, the groups of urgent message pulses being ordered first, each group being preceded, in the pulse trains, by a group head pulse not corresponding to a message and whose amplitude is different from that message pulses, the modification of a message pulse of a group resulting in the modification of the head pulse of this group, in that the central unit controls the sending, in a cyclic manner, on the conductors of transmission of messages, of pulse trains comprising only ordered group head pulses, comprising at least the group head pulses of urgent messages, in that, for each pulse train, the central unit scans by the means of detection of a pulse modification, the head group pulses of urgent messages and the last group head pulse of non-urgent messages , and, in the event that the modification of a group head pulse is detected, the central unit controls the sending, following this modified group head pulse, the group message pulses considered and scans the message pulses to detect a modified pulse.  3. Centralized control device according to claim 1 or 2, characterized in that the pulses comprise a first part (rising edge) nominal to make the coding / decoding logic circuits more reliable and a second part subject to modification between a high threshold and a low allowable threshold.  4. Centralized control device according to claim 1 or 2, characterized in that the transmission of the pulse trains by the central unit is interrupted after a predetermined time following the detection of a message, in that '' at least one accessory unit (11-14) comprises a device generating a reactivation signal on the two message transmission conductors and in that the central unit comprises a device for detecting said reactivation signal so that the emission of a reactivation signal results in the retransmission of the pulse trains on the transmission conductors.  5. Centralized control device according to claim 1, characterized in that each accessory unit (11-14) comprises actuating relays (72) controlled by the decoding means of its module (71).  6. Centralized control device according to any one of the preceding claims, characterized in that the decoding and / or coding means of the modules comprise a counter (81).  7. Centralized control device according to any one of the preceding claims, characterized in that at least one accessory unit (13) comprises a processor (74) sensitive to messages from other accessory units and commanding the minus a function performed by said accessory unit.  8. Centralized control device according to any one of the preceding claims, characterized in that the coding and decoding modules of the accessory units are self-powered at least in part by the pulses of the pulse trains.