Electrical transmission or interconnection systems – Vehicle mounted systems – Automobile
Reexamination Certificate
1999-04-28
2001-05-15
Paladini, Albert W. (Department: 2836)
Electrical transmission or interconnection systems
Vehicle mounted systems
Automobile
C307S064000, C307S066000, C700S079000, C701S114000
Reexamination Certificate
active
06232674
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to on a control device for an on-board electrical system, in particular to a vehicle electric system having at least two batteries that can be charged by a generator.
PRIOR ART
The voltage supply in a motor vehicle that has many electrical consumers can sometimes no longer be achieved with a single battery, and thus increasingly vehicle electric systems are being equipped with two separate batteries, which can be connected to one another via suitable electronic circuits. One such vehicle electric system is known for instance from German Patent 41 38 943.
In this known vehicle electric system, a first battery is intended predominantly to supply the starter, while the second battery serves to supply the other consumers. The two batteries can be connected to one another or disconnected from one another with the aid of a so-called charge-disconnect module, and the connection can be opened or closed by the charge/disconnect module as a function of predeterminable conditions. The voltage supply for the charge/disconnect module is provided from both batteries.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a control device for an electrical system of a vehicle, which has the advantage that it is in continuous communication with the batteries used for power supply purposes; the power consumption in the deactivated state is minimal, and after the ignition switch is actuated, very fast, simple activation of the control device can take place.
The object of the present invention is attained by a control device for a vehicle on-board electrical system which has a power supply device including a generator and at least two batteries charged by the generator and supplying power to consumers. The control device comprises a microcomputer, two end stages respectively including two field effect transistors which are connected to each other and are connectable to their respective batteries and which are switchable so as to establish connection between the batteries only under predetermined conditions. The control device also has two diodes each coupled at one side thereof to a respective end stage and at another side to a further field effect transistor which is connected to the microcomputer. The further field effect transistor switches the control device into operation by a control signal supplied thereto. A connection between the microcomputer and at least one of the batteries is then established. The control signal supplied to the further field effect transistor depends on information obtained at a start.
In its turned off state, the further field effect transistor remains blocked and the control device is operated in a so-called “sleep mode” in which current consumption is very light.
It is als advantageous that with the aid of the control device of the invention, a highly variable design of the on-board electrical system structure is possible. If a bus-capable microcomputer is used in the control device, an information exchange with the on-board electrical system can be achieved. This information exchange can advantageously also extend to an information exchange with the actual control device of the internal combustion engine, so that in the voltage regulation, engine operating conditions can also be taken into account, such as rpm, idling rpm, or load. At the same time, the control device that regulates the engine can take into account variables of a typical generator or the vehicle on-board electrical system; the temperature of the batteries can also be taken into account; this temperature can advantageously be ascertained from easily measured variables by means of an observer function. It is thus possible for the vehicle on-board electrical system control device to vary both charging voltages.
The two batteries are advantageously connected in parallel by means of semiconductor switches, and power MOSFETS are especially suitable.
The battery intended for the starter is advantageously supplied as needed from the on-board electrical system via a direct voltage converter. If the voltage level of one of the two batteries drops below a predeterminable value, then emergency operation can be carried out, in which the starter battery can be charged from the other battery via a direct voltage converter sufficient to assure restarting. By using an error memory located in the on-board electrical system, emergency operation information can be stored in memory and displayed the next time the engine is started or the next time the vehicle is in the shop, and if necessary the operating state of the control device is reset to the sleep mode.
REFERENCES:
patent: 5187382 (1993-02-01), Kondo
patent: 5569997 (1996-10-01), Berger
patent: 5682314 (1997-10-01), Nishino et al.
patent: 5736793 (1998-04-01), Jahrsetz et al.
patent: 41 38 943 C1 (1993-05-01), None
Frey Wunibald
Geiger Albert
Koelle Gerhard
Paladini Albert W.
Robert & Bosch GmbH
Striker Michael J.
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