METHOD FOR HEATING, AND HEATING SYSTEM

Abstract

A method for heating the interior of a motor vehicle and a heating system are described. In the method, electrical energy stored or generated in the motor vehicle or electrical energy fed from an external energy source is fed to an electrothermal transducer and is converted there to thermal energy, which is supplied to a carrier medium for the thermal energy. An electrothermal transducer is used, which is temporarily operated at a higher heating power in the heating-up phase than in the subsequent continuous operation. In this way, the motor vehicle interior is heated up significantly quicker than in the known methods.

Claims

1. A method for heating the interior of a motor vehicle, providing an electrothermal transducer; providing a carrier medium; and providing a heating-up phase, during which the electrothermal transducer is operated at a higher heating power; transferring electrical energy to the electrothermal transducer; converting the electrical energy to thermal energy; supplying the thermal energy to the carrier medium; temporarily operating the electrothermal transducer at the higher heating power of >7 kW, in particular of 30-50 kW, during the heating-up phase than in the subsequent continuous operation of the electrothermal transducer; supplying the electrothermal transducer with the electrical energy required for the higher heating power.

2. The method of claim 1.sub.; further comprising the steps of: providing an external energy source; transferring the electrical energy to the electrothermal transducer from the external energy source.

3.The method of claim 1, further comprising the steps of: generating electrical energy in the motor vehicle; transferring the electrical energy to the electrothermal transducer from the motor vehicle.

4. The method of claim 1, further comprising the steps of providing the electrothermal transducer to be designed for a continuous power of 5-7 kW is used, and being able to temporarily produce a peak power of >7 kW.

5. The method of claim 1, further comprising the steps of providing the motor vehicle to be one selected from the group consisting of an electric vehicle and a hybrid vehicle.

6. The method of claim 1, further comprising the steps of providing the carrier medium to be one selected from the group consisting of air and a cooling medium.

7. The method of claim 1, further comprising the steps of extracting the electrical energy from the vehicle battery.

8. The method of claim 1, further comprising the steps of: generating the electrical energy by recuperation; converting the electrical energy to thermal energy.

9. The method of claim 8, further comprising the steps of: providing the electrothermal transducer to be a braking resistor; generating the thermal energy is generated by using the braking resistor.

10. The method of claim 1, further comprising the steps of: providing a heating period; temporarily supplying the electrothermal transducer with the electrical energy required for the higher heating power at the beginning of the heating period; supplying the electrothermal transducer with electrical energy required for a lower continuous power after the heating period.

11. A heating system for a motor vehicle, comprising: a device for storing, generating or feeding electrical energy; a carrier medium; an electrothermal transducer being part of the device, the electrothermal transducer capable of being operated in a heating-up phase, the electrothermal transducer to which the electrical energy is fed and which the electrothermal transducer converts the electrical energy to thermal energy and supplies the thermal energy to the carrier medium; a supply system in communication with the electrothermal transducer; wherein the electrothermal transducer is configured such that the electrothermal transducer is temporarily operated at a higher heating power of >7 kW, in particular of 30-50 kW, in the heating-up phase than in the subsequent continuous operation, and the supply system supplies the electrothermal transducer with the electrical energy required for the temporary higher heating power from the device for generating, storing or feeding electrical energy.

12. The heating system of claim 9, the heating system further comprising a heat exchanger for a cooling medium, wherein the cooling medium is used as the carrier medium.

13. The heating system of claim 9, further comprising a recuperation system for generating electrical energy, wherein the heating system is connected to the recuperation system.

14. The heating system of claim 11, the recuperation system further comprising: a braking resistor, the braking resistor used as the electrothermal transducer; wherein the braking resistor converts the generated electrical energy to thermal energy.

15. The heating system of claim 9, further comprising: a control system being part of the heating system; wherein the control system switches the electrothermal transducer temporarily to the higher heating power and then to continuous operation at a lower heating power.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention is explained in detail below with reference to an exemplary embodiment in connection with the drawing. In the drawing:

[0025] FIG. 1 shows a block diagram that shows the most important constituent parts of a heating system of a motor vehicle; and

[0026] FIG. 2 shows a graph that shows the heating power, the cooling medium temperature and the interior temperature over time for a system according to the invention (new system) and a system according to the prior art (old system).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0028] The system schematically illustrated in FIG. 1 has a vehicle battery 1 and an electrothermal transducer 2, which converts electrical energy to thermal energy. When a vehicle interior 4 is intended to be heated, the electrothermal transducer 2 is actuated. In this case, the electrothermal transducer is a power transducer (power resistor), which temporariy delivers a higher power (for example 30 kW or more) in order to heat up the interior 4 of the motor vehicle as quickly as possible.

[0029] In the embodiment illustrated here, the heating system further has a cooling medium/air heat exchanger 3. The thermal energy delivered by the electrothermal transducer is fed to a cooling medium, from which the thermal energy in the heat exchanger 3 is transferred to the air of the motor vehicle interior 4 to be heated.

[0030] The system is further provided with a braking resistor 5, which in this case also acts as an electrothermal transducer. The vehicle that has the heating system illustrated here is an electric vehicle in which, during a braking process, the associated electric motor is operated by generator and provides electrical energy by recuperation to the braking resistor 5, which converts the electrical energy to thermal energy. In this case, the braking resistor is also a power transducer, which temporarily delivers a higher power. The air in the motor vehicle interior 4 is likewise heated up using the generated thermal energy.

[0031] In the heating system illustrated here, a control system (not illustrated) may, for example, remove thermal energy from the braking resistor 5 when the thermal energy accumulates or extract the required thermal energy from the vehicle battery 1 when no thermal energy is generated by recuperation. Both systems may also operate together.

[0032] Instead of the electrical transducer 2 and the braking resistor 5 described above, a single electrothermal transducer may also be provided, which is supplied with electrical energy from the vehicle battery or with electrical energy generated by recuperation (where applicable also using electrical energy fed from outside), wherein a control system may control the type of energy feed as required.

[0033] The top graph of FIG. 2 shows the heating power of the system according to the invention (illustrated using dashes) and of a system of the prior art (illustrated using a solid line). It is seen that the electrothermal transducer or braking resistor is temporarily operated at a very high power at the beginning of the heating period, with the result that the motor vehicle interior heats up quickly. The heating power is in this case approximately double the magnitude of that of a known electric heater whose maximum power is restricted to approximately 5-7 kW. Whereas the known electric heater is operated constantly (at continuous power), the electrothermal transducer provided in accordance with the invention is stopped after a relatively short period in high-power operation and is operated further at a power below that of the conventional electric heater until the end of the heating period.

[0034] The center graph of FIG. 2 shows the profile of the cooling medium temperature in the system according to the invention (illustrated using dashes) and in a system of the prior art (illustrated using a solid line). It is seen that in the system according to the invention the cooling medium temperature increases very quickly to a peak value and then remains approximately constant. In contrast, in the prior art, the temperature increases only relatively slowly.

[0035] The same applies to the interior temperature shown in the bottom graph. In this case, too, the temperature in the system according to the invention, illustrated using dashes, increases much more steeply than the temperature in the known system (illustrated using a solid line).

[0036] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.