The invention relates to a motor vehicle comprising an air-conditioning system which has an electrically operated compressor, a generator, which can be operated by a vehicle drive, for generating electrical power, a battery which can be charged by the electrical power generated by the generator, and a solar module for generating electrical power. The invention relates, in particular, to a motor vehicle of this type comprising a hybrid drive which has one vehicle drive based on fossil fuels and one vehicle drive based on electrical power.
Since the power required for conventional air-conditioning of a motor vehicle interior is provided by the internal combustion engine of the motor vehicle, it is necessary to find other concepts for air-conditioning when a vehicle is parked and the internal combustion engine is at a standstill. A useful approach is disclosed in DE 199 03 769 A1. Said document describes using the electrical power provided by a solar module to operate fans for ventilating the passenger compartment. Solar power which is not required for operating the fans is temporarily stored in the vehicle battery. The motor-vehicle air-conditioning system can then be operated following this solar-powered ventilation, with an electrically operated compressor being provided for this purpose. As a result, operation of the vehicle air-conditioning system is started at a lower temperature level than would be the case without solar-powered ventilation. In this way, it is possible to adjust the temperature of the motor vehicle to a tolerable level before operation, that is to say before a person enters said motor vehicle, even on hot days.
In concepts of this type which employ solar power, the power of the solar-power system, the storage capacity of the vehicle battery, the efficiency of the vehicle battery and the electrical power consumption during the various modes of operation involved, amongst other things, have to be taken into account. Particularly on the basis of these variables, it is desirable to use the improvement potential for air-conditioning when a vehicle is parked on the basis of a solar power supply system and to optimize air-conditioning when a vehicle is parked.
Particular attention is to be paid to feeding the electrical power generated by the solar module. This involves, in particular, adapting the various voltages generated, stored and required in the motor vehicle and efficiently storing the generated power.
The invention is based on the object of feeding the power provided by a solar module in a suitable manner to the electrical system of a motor vehicle, particularly in the case of a vehicle with a hybrid drive.
This object is achieved by the features of the independent claims. Advantageous embodiments of the invention are specified in the dependent claims.
According to a first aspect of the invention, said invention builds on the generic motor vehicle in that a further battery is provided which can be charged by the power generated by the solar module, and in that the electrically operated compressor can be operated by power stored in the first battery and/or in the further battery. In this way, it is possible to store the electrical power provided by the solar module independently of the power which is provided in a conventional manner by the generator of the vehicle.
Therefore, no provisions need to be made which permit the power provided by the solar module to be fed to the normal vehicle battery. Instead, a conventional system can be additionally fitted with a solar module and an additional battery in a simple manner.
This is useful particularly when the further battery has a different operating voltage than the battery which can be charged by the generator, and when the operating voltage of the further battery substantially corresponds to the voltage generated directly or indirectly by the solar module. The operating voltage of the further battery can therefore be matched directly to the requirements of the load predominantly supplied with power by this further battery. If, for example, the electrical compressor of the air-conditioning system is operated in a particularly efficient manner on the basis of an operating voltage of 48 V, the electrical power provided by the solar module can be adjusted to this voltage value by a DC/DC converter and be stored in a power with such an operating voltage from the outset. If the electrical compressor is operated by the normal vehicle battery, which has an operating voltage of 12 V for example, it is thus possible to transform the voltage to the desired voltage level by means of a DC/DC converter.
According to a second aspect of the invention, said invention relates to a motor vehicle comprising a hybrid drive, it being possible for the battery to be charged by the power generated by the solar module, and it being possible for the electrically operated compressor to be operated by power stored in the battery. Motor vehicles with hybrid drives, that is to say with one vehicle drive based on fossil fuels and one vehicle drive based on electrical power, employ as standard a sophisticated system for providing suitable voltages. For example, batteries are provided which operate at voltage values of 200 V. In order to drive the motor vehicle with the power stored in the batteries, said power is frequently transformed into an AC voltage at a suitable voltage level by means of an inverter/converter. The electrical system of a hybrid vehicle therefore provides good conditions for including the electrical power provided by the solar module in a suitable manner, in particular by virtue of the use of additional and/or existing inverters/converters and DC/DC converters.
It is particularly preferred for the vehicle drive based on electrical power and the electrically operated compressor to be supplied with power by the same battery 18. The vehicle can therefore manage with a single battery or with a single battery pack using suitable inverters/converters or converters.
It is useful in this connection for means to be provided which match the voltage provided by the generator and/or the solar module to the operating voltage of the battery. Even if it is feasible, in principle, for the solar module and the generator to supply voltages which can be applied directly to the battery, it is generally useful and necessary to operate the generator and the solar module in the range of their optimum operating voltages and to match them to the battery voltage by means of simple converters and/or inverters/converters.
For comparable reasons, provision is made for means to be provided which match the voltage tapped off from the battery to the operating voltage of at least one load. The invention also relates to a power supply system for a motor vehicle according to the invention.
The invention will now be explained by way of example with reference to the accompanying drawings of particularly preferred embodiments.
In the drawings:
In the following description of the drawings, identical reference symbols denote identical or comparable components.
A vehicle drive 14 drives a generator 16. Said generator is connected to a battery 18 in order to charge said battery.
Also provided is a solar module 22 which is connected to a circuit node 46 via a DC/DC converter 44, with this circuit node 46 being connected both to the power supply means of the air-conditioning system 10 and to a further battery 20.
The present system is now designed such that the DC/DC converter 44 provides a different voltage than the generator 16. For example, the generator usually provides a voltage of 12 V, whereas the DC/DC converter 44 converts the voltage provided by the solar module 22 to a voltage value of 42 V. This may be useful when the electrical compressor 12 which is supplied with power by the solar module 22 or by the further battery 20 is to be supplied with an operating voltage of 42 V. In this case, the voltage provided by the further battery 20 can be supplied directly to the electrical compressor 12. In order to likewise permit the power which is generated by the battery 18, which is charged by the generator 16, to be used to drive the electrical compressor, a further DC/DC converter 48 is provided between the battery 18 and the circuit node 46. The power stored in the battery 18 can be used without changing the voltage value in order to supply electrical power to the blowers 40, 42. If the supply of power to these blowers 40, 42 is taken over by the power stored in the further battery 20 or the electrical voltage provided by the DC/DC converter 44, that is to say by the voltage applied to the circuit node 46, a DC/DC converter 50 is provided for this purpose. Said DC/DC converter converts the voltage corresponding to the operating voltage of the further battery 20 to a value which corresponds to the operating voltage of the battery 18.
The result is therefore a system which has two batteries 18, 20, with each battery 18, 20 being able to undertake all the power supply tasks relating to the air-conditioning system. The battery 18 which can be charged by the generator 16 can be designed in a conventional manner. The further battery 20 can be selected depending on the operating voltage of the compressor, in particular with an increased operating voltage for providing an increased power. Instead of a simple DC/DC converter 48 between the battery 18 and the circuit node 46, a device can also be provided which permits the battery 18 to be charged by the power provided by the solar module 22.
With regard to their interaction, the components illustrated in
In the embodiment illustrated in connection with
The compressors or compressor combinations (
The features of the invention disclosed in the above description, in the drawings and in the claims may be essential for implementing the invention both on their own and in any desired combination.
Number | Date | Country | Kind |
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10 2006 003 424.4 | Jan 2006 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/DE2007/000138 | 1/22/2007 | WO | 00 | 6/13/2008 |