Patent Application
20100308647
The invention relates to a device for controlling components of a vehicle. The device has a plurality of control units which are supplied by a power supply circuit that is connected on one side to an accumulator and on the other side to the control units. Some of the control units can be switched off by means of a quiescent current switch which is connected directly into the current path between the accumulator and the control units, while another group of the control units is connected to the accumulator via the ignition/starter switch. An on-board vehicle power system control unit, which is continuously supplied with power via the accumulator, actuates the quiescent current switch and the ignition/starter switch for the switching process.
Contemporary means of transportation, for example motor vehicles and utility vehicles, have complex databus systems to which a large number of control units are connected. The control units exchange messages with one another via a databus in order to actuate the components correspondingly. Sensors and actuators are connected directly to the control units in order to make available measured values for the control units and actuate electric motors, switches and relays. In addition to the transmission of data by telecommunications via the databuses with the smallest possible current, the individual control units must be supplied with energy in order to supply current to their microcomputers, on the one hand, and to their sensors and actuators, on the other.
A serious problem in this regard is the demand for quiescent current of such databus systems: when a deactivation process for a control unit fails, the control unit continues to draw current from the vehicle battery, (that is, the accumulator), and therefore discharges the accumulator. For this reason, in addition to the ignition/starter switch, known control unit architectures have an additional quiescent current switch which disconnects the power supply line by switching off when the last control unit is powered down after the internal combustion engine has been switched off. As a result, it is impossible for current to continue to be drawn from the accumulator. The quiescent current switch galvanically separates the power supply line from the accumulator.
German patent document DE 103 30 446 A1 discloses a vehicle with networked control units which are still active in predefined run-on phases after the drive motor has been switched off. For this purpose, switching-off signals are fed to each control unit via a control line, so that the internal voltage regulator of the control unit can switch off said control unit.
German patent document DE 197 24 570 A1 discloses a control unit which switches a high power load on and off. Because of the load “jump” during the switching on and switching off process, information is transmitted in advance from the control unit to the voltage regulator in order to prevent a failure or a disruption of the voltage supply. The power requirements in the system can therefore be adapted in advance.
German patent document DE 103 12 553 B3 describes a motor vehicle with control units that are connected to energy supply lines by means of a monitoring control unit in a deactivable fashion. If the control units are powered down to a state of rest, the monitoring control unit measures the quiescent current which is actually taken up and places each control unit which deviates from the predefined quiescent current range in a reset mode. For this purpose, the current path of each control unit can be disconnected by a switching element.
German patent document DE 10 2004 054 721 A1 describes a device for reducing the quiescent current in a vehicle electronic system. A central control unit is networked to other control units via a databus. The central control unit has means for short-circuiting the databus to ground in order to initiate the quiescent state. As soon as the short circuit to ground is detected, the control units are powered down into the state of rest.
German patent document DE 100 63 753 A1 describes a voltage supply for vehicle control units, which voltage supply is powered down incrementally after the internal combustion engine has been switched off. The maintenance of the voltage (referred to as “running on”) is divided into a first and second running on phase. The engine control unit and other components are connected here to the battery via a main relay. A further voltage supply which can be switched off connects from the battery to the fuel pump via the ignition/starter switch. Voltage is applied to terminal 15 when the ignition switch is activated. Thereafter, the main relay is switched on, so that the engine control unit can be switched on. When the engine is switched off, the voltage at terminal 15 is switched off. The control pins at the control unit remain active in order to switch off the further circuit. At the end of each running on phase, a control signal is output via the control pins in order to cause the circuit to be switched off.
One object of the present invention is to provide an alternative device with a power supply circuit which can be operated with a quiescent current switch that has a lower current switching capability, compared to the known systems, and can therefore be implemented more cost-effectively.
This and other objects and advantages are achieved by the control device according to the invention, in which at least one control unit has two power supply terminals that are each protected against overload by a fuse. The first power supply terminal is connected to a voltage regulator for the microcomputer of the control unit and to the accumulator via the quiescent current switch, while the second power supply terminal is connected to the accumulator via a fuse. The first power supply terminal supplies the microcomputer with energy, while the second power supply terminal actuates one power switch per control unit in order to supply energy to the output stages of an actuator which is operated by the control unit. The on-board vehicle power system control unit activates the quiescent current switch in order to deactivate the microcomputer, while the power switches of the same control unit are supplied with power.
The inventors have determined that, by dividing the common power supply line for the individual groups of control units into a low current supply line and a high current supply line, it is possible to dispense with the costly relay as a quiescent current switch for its current switching capability. According to the invention, therefore, a low current supply line supplies power to the microcomputers of the control units, and a high current supply line operates the output stages of the actuators via the power switch in each control unit. If the control unit system is then powered down, the low current supply line is simply disconnected by the quiescent current switch, while the high current supply line remains connected directly to the accumulator. Since MOSFET power transistors (which have a very high internal resistance in the switched-off state) are generally used as power switches within the control units, additional disconnection of the power supply path by means of the quiescent current switch is unnecessary. Since only the low current supply line is disconnected by means of the quiescent current switch, the switching power of the quiescent current switch can be considerably reduced compared to the classic control unit systems.
Two types of known control unit systems, such as already currently in use in vehicles, are illustrated schematically in
Compared to this prior art, the device according to the invention presents an alternative control unit architecture which introduces two power supply terminals per control unit. Only the power supply line for the microcomputers is disconnected by the quiescent current switch, while the load circuits for the actuators are connected directly to the accumulator without a quiescent current switch.
In one development of the invention, the microcomputer and the power switch are arranged within the control unit on a printed circuit board, with the control electrode of the power switch being actuable directly by the microcomputer, and the two load current terminals of the power switch being led separately out of the control unit via an interface. Since the microcomputer and the power switch are arranged on a printed circuit board, the costs can be reduced further since a discrete power switch outside the control unit generates additional costs, and the multi-component nature of the system reduces reliability.
The low current supply terminal of each control unit is denoted by +C, while the power supply terminal of the load current is denoted by +P. The energy supply line +P, which is connected directly to the accumulator in an electrically conductive fashion, is provided without a quiescent current switch, while the power supply lines +C of the microcomputers are led to the quiescent current switch. In this way, the microcomputers are switched to the quiescent state, while the power switches are continuously conductively connected to the accumulator.
The on-board vehicle power system control unit controls the quiescent current switch in order to deactivate the microcomputers at a predetermined time, and can also activate a reset switch in order to actuate an additional reset supply line. Specific microcomputers can be jointly placed in a reset process via the reset supply line without the voltage regulators having to be switched off via the quiescent current switch. As a result, a controlled restart is possible in the event of a malfunction of a control unit (for example during parking maneuvers of the vehicle). Such a reset function via the reset supply line can be carried out only for specific control units, for example telematics control units or passenger compartment control units.
A control unit can then be placed into a reset mode via the reset supply line. In this context, at the engine control unit it is possible, for example, not only to carry out the reset for the engine control unit but also to switch off all the components at the engine control unit. As a result, for example in a parking situation of the vehicle, the engine control unit can be placed in a reset mode, while at the same time the actuators are deactivated. After a defined run-up mode, the engine control unit can then be restarted again in order, if appropriate, to overcome logic problems at the engine control unit.
The first power supply terminals +C of various control units can preferably be connected to the quiescent current switch via a common fuse. As a result, it is possible to dispense with fuses for the microcomputers on the low current supply line.
The power supply terminal +C is usually configured as a low current terminal for currents of less than 1 ampere since it is supplied with current via logic circuits, microcomputers and low current loads. In contrast, the load current via the high current supply terminal +P to the power transistor can be within a range of several amperes to, for example, 100 amperes, in order to actuate the actuators correspondingly.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
According to the invention, a plurality of similar control units are connected to the power supply circuit and in each case the first power supply terminals +C are connected jointly to the accumulator 12 via the quiescent current switch 13. Since the first power supply terminal +C is coupled to the respective voltage regulators of the control units, which in turn supply current to the microcomputer μC, it is necessary to place all the microcomputers jointly in the safe quiescent state, by means of the quiescent current switch 13, after the databus system has been powered down.
On the other hand, when corresponding power switches 17 (for example MOSFET transistors) are used, the output stages 18 and the actuators 19 do not have to run via the quiescent current switch, as the internal resistance in the switched MOSFET power switch is very high, so that the power losses are in the micro-ampere range. For this reason, it is not necessary also to switch off the power supply line 20 via the quiescent current switch. According to the invention, this provides a considerable advantage in that the quiescent current needs only be configured to switch off the microcomputer power supply via the power supply terminal +C. The power supply line 20 on which the powered actuators are supplied with power is then not switched off by means of a quiescent current relay, as is the case for the quiescent current switch 13. In this way, according to the present invention it is possible to achieve a considerable cost saving since the quiescent current switch places only part of the load (specifically, the microcomputers) in the quiescent state. The actuators 19 of a plurality of similar control units are switched off via the internal power switches of the control units, and the power losses are low in this case because of the MOSFET transistors which are used.
In addition to these classic control units, in
The two other control units 4 and 5 according to the invention likewise have first power supply terminals +C and second power supply terminals +P for the load currents. The low current power supply terminals +C of the control units 4 and 5 can be led, in a bundled form, via a fuse 16 to the power supply line to the quiescent current switch 13 and to the accumulator 12. As a result, fuses 16 for a plurality of control units can be dispensed with on the low current side. In the control units 4 and 5, the structure according to the invention is shown by means of the voltage supply terminal +C for the power supply of the microcomputers and the power supply terminal +P for the load current of the actuators 19 which are led via the load switch 17 which is internal in the control unit. As a result of the separation of the microcomputer power supply terminals +C and load current supply terminals +P, the dimensioning of the quiescent current switch relay 13 can result in a low current switching capacity, which provides considerable savings in terms of the quiescent current switch 13.
The on-board vehicle power system management control unit 11 also actuates the ignition/starter switch 14, which is activated electronically in modern vehicles. Control units 10 are arranged on this ignition/starter switch 14 and they are powered up when the engine starts and powered down when the engine is switched off. The parking control unit is affected by this, for example, since its function is no longer necessary after the internal combustion engine has been switched off. The reset control units 3 and 9 include, for example, the engine control unit MSG which is connected to the power supply line 20 and therefore to the accumulator 12 via the fuse 16 and the central switch on the power supply line 87M. The power supply line 24 which is connected to the reset power supply line 22 can be switched off by means of a relay 25, which ensures that at the same time the switch for the load circuit 23 is opened.
The other reset-enabled control unit 3 can be, for example, the passenger compartment control unit which, in the event of malfunctions, can be placed in a defined fashion in the reset state. The control unit 6 is illustrated by way of example of a group of similar control units according to the invention with two power supply terminals +C and +P, which group makes possible the inventive advantage of the relatively low dimensioning of the quiescent current relay switch 13. As a result, the considerable cost effect during mass production of means of transportation can be achieved when the quiescent current switch 13 is configured.
The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2006 042 657.6 | Sep 2006 | DE | national |
This application is a continuation of PCT International Application No. PCT/EP2007/007577, filed Aug. 30, 2007, which claims priority under 35 U.S.C. §119 to German Patent Application No. 10 2006 042 657.6, filed Sep. 12, 2006, the entire disclosure of which is herein expressly incorporated by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2007/007577 | 8/30/2007 | WO | 00 | 8/24/2010 |
