Motor vehicle electric system
First Claim
1. A motor vehicle electric system comprisingan internal combustion engine and, mechanically connected thereto, an integrated starter-generator that charges a double layer capacitor and a first battery to a first voltage via a bi-directional AC/DC converter in generator mode and is driven by the energy stored in the double layer capacitor or in the battery in motor mode, an intermediate circuit capacitor is arranged between the positive and negative direct voltage terminals of the bi-directional AC/DC converter, a first switch is provided via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the plus pole of the battery, the minus pole of the AC/DC converter is grounded, and a second switch is provided via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the positive terminal of the double layer capacitor, the negative terminal of said AC/DC converter is grounded.
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Accused Products
Abstract
A starter-generator (ISG) is mechanically connected to an internal combustion engine (BKM), comprises a bi-directional AC/DC converter (1), and can be connected to an accumulator (B1) by means of a first switch (S1), and connected to a double layer capacitor (DLC) by means of a second switch (S2). The accumulator (B1) is either connected to the double layer capacitor (DLC) by means of a control circuit (PWM), or the accumulator (B1) and the double layer capacitor (DLC) are connected to a bidirectional DC/DC converter (3) and to a second accumulator (B2) by means of a third switch (S3) and a fourth switch (S4).
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Citations
28 Claims
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1. A motor vehicle electric system comprising
an internal combustion engine and, mechanically connected thereto, an integrated starter-generator that charges a double layer capacitor and a first battery to a first voltage via a bi-directional AC/DC converter in generator mode and is driven by the energy stored in the double layer capacitor or in the battery in motor mode, an intermediate circuit capacitor is arranged between the positive and negative direct voltage terminals of the bi-directional AC/DC converter, a first switch is provided via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the plus pole of the battery, the minus pole of the AC/DC converter is grounded, and a second switch is provided via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the positive terminal of the double layer capacitor, the negative terminal of said AC/DC converter is grounded.
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12. A method of operating a motor vehicle electric system comprising an integrated starter-generator, the steps-of comprising:
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charging a double layer capacitor and a battery to a first voltage via a bi-directional AC/DC converter in a generator mode, driving the starter-generator by the energy stored in the double layer capacitor or in the battery in a motor mode, arranging an intermediate circuit capacitor between the positive and negative direct voltage terminals of the bi-directional AC/DC converter, providing a first switch via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the plus pole of the battery, the minus pole of the AC/DC converter is grounded, and providing a second switch via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the positive terminal of the double layer capacitor, the negative terminal of the AC/DC converter is grounded. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A motor vehicle electric system comprising an internal combustion engine and, mechanically connected thereto, an integrated starter-generator that charges a double layer capacitor and a battery to a first voltage via a bi-directional AC/DC converter in generator mode and is driven by the energy stored in the double layer capacitor or in the battery in motor mode, wherein an intermediate circuit capacitor is arranged between the positive and negative direct voltage terminals of the bi-directional AC/DC converter, a first switch is provided via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the plus pole of the battery, the minus pole of the converter is grounded, and a second switch is provided via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the positive terminal of the double layer capacitor, the negative terminal of the converter is grounded, whereby the system is operable to
charge the intermediate circuit capacitor via the AC/DC converter to a voltage value corresponding to the voltage at the double layer capacitor or the 36 V battery, determine the working direction of the converters (step-up or step-down), and control the positions of switches.
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24. A motor vehicle electric system comprising an internal combustion engine and, mechanically connected thereto, an integrated starter-generator that charges a double layer capacitor and a battery to a first voltage via a bi-directional AC/DC converter in generator mode and is driven by the energy stored in the double layer capacitor or in the battery in motor mode, wherein an intermediate circuit capacitor is arranged between the positive and negative direct voltage terminals of the bi-directional AC/DC converter, a first switch is provided via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the plus pole of the battery, the minus pole of the converter is grounded, and a second switch is provided via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the positive terminal of the double layer capacitor, the negative terminal of the converter is grounded wherein
when the integrated starter-generator is in generator mode: -
the intermediate circuit capacitor is charged to a predefinable voltage when the switches are non-conducting, the battery is charged when the first switch is conducting, the double layer capacitor is charged when the second switch is conducting, and when the integrated starter-generator is in motor mode;
the starter-generator is driven with energy from the battery when the first switch is conducting, and the starter-generator is driven with energy from the double layer capacitor when the second switch is conducting.
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25. A method of operating a motor vehicle electric system comprising an integrated starter-generator comprising the steps of:
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charging a double layer capacitor and a battery to a first voltage via a bi-directional AC/DC converter in a generator mode, driving the starter-generator by the energy stored in the double layer capacitor or in the battery in a motor mode, arranging an intermediate circuit capacitor between the positive and negative direct voltage terminals of the bi-directional AC/DC converter, providing a first switch via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the plus pole of the battery, the minus pole of the converter is grounded, providing a second switch via which the positive direct voltage terminal of the bi-directional AC/DC converter can be connected to the positive terminal of the double layer capacitor, the negative terminal of the converter is grounded, charging an additional battery via a bi-directional DC/DC converter by the battery, providing a third switch via which the plus pole of the first battery can be connected to a positive terminal of the bi-directional DC/DC converter, and providing a fourth switch via which the positive terminal of the double layer capacitor can be connected with the same positive terminal of the bi-directional DC/DC converter. - View Dependent Claims (26, 27, 28)
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Specification