US20080302878A1

US20080302878A1 - Method for Controlling an Air-Conditioning System of a Vehicle Whose Top is Opened

Info

Publication number: US20080302878A1
Application number: US12/089,856
Authority: US
Inventors: Karsten Helms
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2005-10-12
Filing date: 2006-10-11
Publication date: 2008-12-11
Also published as: WO2007042268A1; DE102005048833A1; EP1934064B1; ATE452781T1; ES2340071T3; EP1934064B8; DE502006005747D1; EP1934064A1

Abstract

In a method for regulating an air-conditioning system of a vehicle whose top is open, air whose temperature and mass flow rate are regulated as a function of at least the control variables of the setpoint temperature of the passenger compartment and the actual temperature of the passenger compartment being fed to a passenger compartment of the vehicle via a plurality of vent openings. The speed of the vehicle is measured and, when it increases, the air-mass flow rate, which is fed to the passenger compartment through vent openings at lower positions, is reduced and the air-mass flow rate, which is fed to the passenger compartment through vent openings at higher positions, is increased.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application of International Application No. PCT/EP2006/009806 filed Oct. 11, 2006, which designates the United States of America, and claims priority to German application number 10 2005 048 833.1 filed Oct. 12, 2005, the contents of which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a method for regulating an air-conditioning system of a vehicle whose top is open. The vehicle is a convertible vehicle, in particular. The top of a convertible vehicle can be opened and closed. When the top is closed, the air-conditioning system is to be regulated in the conventional manner. The invention relates to the regulation of the air-conditioning system when the top is open and the transition from the open to the closed states of the top and from the closed to the open states of the top. The vehicle comprises a passenger compartment, to which air whose temperature and mass flow rate are regulated as a function of at least the control variables of the setpoint temperature of the passenger compartment and the actual temperature of the passenger compartment is fed via a plurality of vent openings for air-conditioning.

BACKGROUND

WO 2004/052668 A1 discloses a method for regulating an air-conditioning system for a convertible vehicle, in which method when the convertible top is open, in addition to the information about the ambient temperature, solar radiation, setpoint interior temperature and actual interior temperature, which information is conventionally used for air-conditioning with the convertible top closed, the vehicle speed is also taken into account. If a rise in the speed of the vehicle is detected in comparison with a previously sensed speed, the blowing-out temperature is increased by a value and the air-mass flow rate is kept constant. If this increase in the blowing-out temperature is not sufficient to compensate a reduction in temperature caused by the rise in the speed of the vehicle, the air-mass flow rate is increased by a value in order to provide support. Alternatively, it is also possible for only the air-mass flow rate to be increased by a value and for the blowing-out temperature to be kept constant. If a cooling is to be achieved with the air-conditioning system and if a rise in the speed of the vehicle is detected in comparison with a previously sensed speed, either the blowing-out temperature is increased by a value and the air-mass flow rate is kept constant or only the air-mass flow rate is reduced by a value.
It has been seen that both the conventional regulation of the air-conditioning system optimized for a closed top and the regulation of the air-conditioning system where the open top is taken into consideration cannot provide comfortable air-conditioning for the passengers. The temperature distribution inside the passenger compartment when the top is open does not sufficiently take into account the circumstances in this state of the vehicle. It has been established, for example, that the temperature in the foot-well is excessively high, while the temperature in the region of the passengers' arms tends to be too low. In addition, the noise associated with air-conditioning is in many cases too loud and bothersome to the passengers.

SUMMARY

A method of the aforementioned kind can be specified, which method enables a more comfortable regulation of the air-conditioning system in a vehicle whose top is open, thereby resulting in a pleasant air-conditioning for the passengers in this state of the vehicle. According to an embodiment, a method for regulating an air-conditioning system of a vehicle whose top can be opened, may comprise the steps of: regulating air temperature and mass flow rate as a function of at least the control variables of a setpoint temperature of a passenger compartment and an actual temperature of the passenger compartment being fed to a passenger compartment of the vehicle via a plurality of vent openings wherein the regulating parameters used for regulating the air-conditioning system when the top is open are different from those used when the top is closed, using intermediate values of the regulating parameters during the opening and closing of the top, wherein the intermediate values approximate to the regulating parameters for an open top faster during the opening of the top than the rate at which the intermediate values approximate to the regulating parameters for a closed top during the closing of the top.
According to a further embodiment, the speed of the vehicle may be determined and, as the speed of the vehicle increases, the air-mass flow rate, which is fed to the passenger compartment through vent openings at lower positions, is reduced and/or the air-mass flow rate, which is fed to the passenger compartment through vent openings at higher positions is increased, or as the speed of the vehicle increases, the air-mass flow rate is increasingly shifted from the vent openings for the foot-well of the passenger compartment at least to vent openings selected from the group consisting of vent openings for the torso, the hands and the forearms of the passengers. According to a further embodiment, the temperature of the air fed to the passenger compartment may be higher than the actual temperature of the passenger compartment. According to a further embodiment, the air-mass flow rate may be conveyed via a blower, whose power is regulated by means of a basic blower voltage characteristic, and that the basic blower voltage characteristic is lowered compared to the basic blower voltage characteristic when regulating the air-conditioning system with the top closed. According to a further embodiment, the air-mass flow rate may be conveyed via a blower and the blower power may be limited as a function of the vehicle speed and the limit value depends on the sound volume of the blower. According to a further embodiment, the limit value may be selected in such a way that the blower noise does not exceed the airflow noise. According to a further embodiment, the airflow noise may be measured. According to a further embodiment, the airflow noise may be determined in advance and the limit value for the blower power may be selected by means of a characteristic, which contains the blower noise as a function of the blower power as well as the airflow noise as a function of the traveling speed. According to a further embodiment, the solar radiation hitting the passenger compartment may be measured and the measured values of the solar radiation may constitute another control variable for regulating the temperature and/or the mass flow rate of the air fed to the passenger compartment, the influence of the measured values of the solar radiation when the top is open being stronger than the influence of the measured values of the solar radiation when regulating the air-conditioning system with the top closed. According to a further embodiment, the solar radiation may be measured in at least two positions and differences in the measured values in different positions are not considered when regulating the temperature or the mass flow rate of the air fed to the passenger compartment. According to a further embodiment, the value for the actual temperature of the passenger compartment, which value is used when regulating the air-conditioning system, may be calculated from the measured value of a temperature sensor of the passenger compartment and the measured value of an outside temperature sensor. According to a further embodiment, the air-mass flow rate may change over a plurality of steps or continuously as the speed of the vehicle increases. According to a further embodiment, the air-mass flow rate may change inversely when the vehicle speed returns to a lower level.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained with reference to exemplary embodiments and the FIGURE.

The FIGURE schematically shows an example of a regulator for an air-conditioning system which regulator enables the implementation of the method according to various embodiments.

DETAILED DESCRIPTION

According to various embodiments of a method, the speed of the vehicle can be measured and as the speed of the vehicle increases, the air-mass flow rate, which is fed to the passenger compartment through vent openings at lower positions, is reduced and the air-mass flow rate, which is fed to the passenger compartment through vent openings at higher positions, is increased. As the speed of the vehicle increases, the air-mass flow rate is thus advantageously increasingly shifted from vent openings for the foot-well of the passenger compartment to vent openings for the torso and/or hands and/or arms or forearms of the passengers.
The method can be used both in the heating operation and in the cooling operation of the air-conditioning system. However, it has been seen that the method according to various embodiments can be particularly advantageous in the heating operation in which the temperature of the air fed to the passenger compartment is higher than the actual temperature of the passenger compartment. This is because when the top is open in the heating operation, the lack of counter pressure in the passenger compartment results in more hot air being conveyed into the vehicle as the speed increases. In the conventional regulation of the air-conditioning system, this results in overheating the feet of the passengers. This effect where the passenger's feet are overheated is prevented by the method according to various embodiments since the hot air comes increasingly from the so-called dashboard vents or air discharge ports. These dashboard vents, in particular, can be oriented in such a way that the hot air flowing out is used for heating the passengers' hands and forearms. It is particularly these body parts of the passengers that get cold when the top is open. Furthermore, this helps to counteract the air turbulence, which increases at higher speeds of the vehicle.
The air-mass flow rate is usually conveyed via a blower or fan, whose power is regulated by means of a basic blower voltage characteristic. According to an embodiment of the method, the basic blower voltage characteristic can be lowered compared to the basic blower voltage characteristic when regulating the air-conditioning system with the top closed. The passenger is intentionally exposed to the present climatic boundary conditions to a greater degree by opening the top of the convertible vehicle. The passenger would like to feel the head wind, i.e., the outside temperature and the solar radiation. Air-conditioning by means of an automatic air-conditioning regulation is possible only to a limited extent in this case since the passenger compartment is not closed. The lowering of the basic blower voltage characteristic results in a defensive regulation of the air-conditioning system. The advantage of such a regulation when the top is open is that the air-conditioning is not bothersome or obtrusive to the passengers.
According to another embodiment of the method, the blower power may be limited as a function of the vehicle speed and the limit value may depend on the sound volume of the blower. The limit value is thus selected in such a way that the blower noise does not exceed the airflow noise, i.e., the other airflow noise that occurs during travel. The airflow conditions and the noise level change strongly as a function of the traveling speed. The other airflow noise occurring during travel increases as the speed increases so that in this case the blower voltage and thus also the blower power of the air-conditioning regulation can be increased such that the blower noise is still below the other airflow noise. However, in this case, the heat removal or heat input can be compensated more effectively.
The airflow noise can be measured during travel by way of example so that the blower power and the sound volume of the blower associated with the blower power can be adapted to the respective airflow noise on an ongoing basis. However, the airflow noise can also be determined in advance. In this case, the limit value for the blower power is selected by means of a characteristic, which contains the blower noise as a function of the blower power as well as the airflow noise as a function of the traveling speed.
According to another embodiment of the method, the solar radiation hitting the passenger compartment may be measured and the measured values of the solar radiation may constitute another control variable for regulating the temperature and/or the mass flow rate of the air fed to the passenger compartment. According to various embodiments, the influence of the measured values of the solar radiation when the top is open is stronger than the influence of the measured values of the solar radiation when regulating the air-conditioning system with the top closed.
When regulating the air-conditioning system, a time constant is assigned to each control variable. This time constant determines the rate at which a change in the control variable affects the temperature and/or the mass flow rate of the air fed to the passenger compartment. According to various embodiments, the time constant assigned to the solar radiation can be smaller when the top is open in comparison with the value when the top is closed. As a result, the regulation of the air-conditioning system reacts faster to a change in the solar radiation. The penetration of the solar radiation is much higher when the top is open than when it is closed. The passengers are directly exposed to the solar radiation, if appropriate. Since the solar radiation is also no longer filtered by the vehicle windows, it has a faster effect on the passengers. A faster reaction of the regulation of the air-conditioning system to a changing solar radiation thus has a positive impact on the air-conditioning of the passenger compartment.
In conventional air-conditioning systems, the solar radiation is measured in at least two positions, particularly on the right and left sides in relation to the direction of travel. It is thus possible to reliably take into account the heat input caused by the solar radiation during air-conditioning. For example, the side that is hit by the solar radiation can be heated lesser or cooled more. However, according to various embodiments, differences in the measured values in different positions when the top is open are not considered when regulating the temperature and/or the mass flow rate of the air fed to the passenger compartment. When the top is open, all passengers are uniformly exposed to the solar radiation that was measured to be the highest. This measured value is therefore taken into consideration in the climate control for all zones of the passenger compartment.
According to another embodiment of the method, that value for the actual temperature of the passenger compartment that may be used when regulating the air-conditioning system is calculated from the measured value of a temperature sensor of the passenger compartment and the measured value of an outside temperature sensor. Particularly that value for the actual temperature of the passenger compartment that is taken into consideration when regulating the air-conditioning system is calculated from fractions of the measured value of the temperature sensor of the passenger compartment and the outside temperature sensor. The value for the actual temperature of the passenger compartment, which value is calculated in this manner, is used particularly when cooling the passenger compartment by means of the air-conditioning system—that is, when the temperature of the air fed to the passenger compartment is lower than the measured value of the temperature sensor of the passenger compartment. It has been seen that when the top is open, the passenger compartment is air-conditioned insufficiently since that value for the actual temperature of the passenger compartment that is taken into consideration when regulating the air-conditioning system is calculated incorrectly. The method according to various embodiments prevents this malfunction of the regulation of the air-conditioning system by calculating the actual temperature of the passenger compartment as specified above. The resulting advantage is that when the top is open, the passengers need not manually intervene in the regulation of the air-conditioning system. Furthermore, an automatic regulation of the air-conditioning system helps achieve a pleasant air-conditioning.
In the method according to various embodiments, the regulating parameters used for regulating the air-conditioning system when the top is open are different from those used when the top is closed. According to yet another refinement of the method, intermediate values of these regulating parameters can be used during the opening and closing of the top. The intermediate values may approximate to the regulating parameters for an open top faster during the opening of the top than the rate at which the intermediate values approximate to the regulating parameters for a closed top during the closing of the top. It has been seen that during the opening and closing of the top, the regulating parameters of the corresponding mode are taken over too rapidly and too slowly respectively. The result is an overreaction of the regulation of the air-conditioning system when closing the top and an insufficient reaction of the regulation when opening the top. When the regulating parameters for an open top are taken over faster when opening the top, it is possible to more rapidly compensate the outer environmental conditions, i.e., the influence of the outside temperature and the solar radiation. On the other hand, when closing the top, the regulation of the air-conditioning system undergoes a gentler and acoustically more appealing transition for this state of the top.
It should be pointed out here that the selection, described above, of the air-mass flow rate of the various vent openings, the regulation of the blower power, the influence of the solar radiation on the regulation of the air-conditioning system, the calculation of the actual temperature of the passenger compartment that is used when regulating the air-conditioning system, and the change in the regulating parameters during the opening or closing of the top can be used individually as well as in any combination when regulating the air-conditioning system of a vehicle whose top is open.
The intention is to air-condition the passenger compartment of a convertible vehicle. For this purpose, an air-conditioning system is provided, which regulates the air-conditioning in the passenger compartment as a function of various control variables. For air-conditioning the passenger compartment, a plurality of vent openings is provided, which feed air, whose temperature and mass flow rate are regulated, to different zones of the passenger compartment.
In the FIGURE, the number of vent openings provided for the foot-well of the passenger compartment are marked by reference numeral 21, the number of vent openings feeding air to the torso, hands, and arms of the passengers is marked with reference numeral 22, and the number of inlets oriented toward the upper region of the passenger compartment, particularly in the direction of the windshield, is marked with reference numeral 23. The vent openings 22 are also referred to as dashboard vents. This division of the vent openings serves only as an example. Naturally, it is also possible to divide the vent openings differently. However, in either case, there are vent openings at lower positions and vent openings at higher positions.
Each vent opening or each number of vent openings 21, 22, and 23 is assigned a control unit, which regulates the temperature and mass flow rate of the air fed to the passenger compartment for the respective vent openings. The control unit 31 is assigned to the vent openings 21 for the foot-well. Control unit 32 is assigned to the so-called dashboard vents 22, and control unit 33 is assigned to the upper vent openings 23.
Control units 31, 32, and 33 are connected to a central control unit 1, which transmits signals to the control units 31, 32, and 33. These signals specify how much air is to arrive into the passenger compartment and at what temperature via the respective vent openings 21, 22, and 23.
The central control unit 1 is further connected to an input device 4, by means of which the passengers can select the setpoint temperature of the passenger compartment.
Furthermore, the central control unit 1 is connected to different sensors, which supply additional control variables for regulating the air-conditioning system in addition to the setpoint temperature of the passenger compartment. A temperature sensor 5, in particular, is provided inside the passenger compartment and a temperature sensor 6 is provided for the outside temperature. Furthermore, two sensors 71 and 72 are provided for measuring the solar radiation on the right and left sides of the convertible vehicle. The measured values of these sensors 5, 6, 71, and 72 are transmitted to the central control unit 1. In addition, the central control unit 1 is connected to a sensor 8, which indicates whether the top of the convertible vehicle is open or closed. If the central control unit 1 determines by means of the sensor 8 that the top is in a closed state, the air-conditioning system is regulated in a manner known per se. Particularly by means of the control variables for the temperature inside the passenger compartment, the outside temperature, and the measured solar radiation, the central control unit 1 determines control variables for the control units 31, 32, and 33 and thus determines how much air is fed to the passenger compartment, at what temperature and via which vent openings so that the difference between the setpoint temperature of the passenger compartment and the actual temperature of the passenger compartment is reduced in a manner that is comfortable to the passengers.
If the central control unit 1 determines by means of the sensor 8 that the top is in an open state, the central control unit 1 changes the regulation of the air-conditioning system in the manner suggested according to various embodiments as described below:
First, the vehicle speed is measured. A speed indicator 9 that is usually present in every vehicle is used for this purpose. The data of this speed indicator 9 can be transmitted, for example, via the vehicle bus to the central control unit 1. In the central control unit 1, a characteristic is stored, which indicates how much air is to be fed and at what temperature via the respective vent openings 21, 22, and 23 to the passenger compartment. This characteristic is formed for an open top in such a way that as the vehicle speed increases, the air-mass flow rate, which is fed to the passenger compartment through vent openings at lower positions, i.e., through the vent openings 21, is reduced and the air-mass flow rate, which is fed to the passenger compartment through vent openings at higher positions, i.e., particularly through the dashboard vents 22, is increased.
According to another design form of this exemplary embodiment, it would also be possible to reduce the temperature of the air fed to the passenger compartment through the vent openings 21 at lower positions and to increase the temperature of the air fed to the passenger compartment through the vent openings 22 at higher positions. Furthermore, a combination of the reduction of the air-mass flow rate and the temperature of the air fed to the passenger compartment through the vent openings 21 at lower positions, and an increase in the air-mass flow rate and the temperature of the air fed to the passenger compartment through vent openings 22 at higher positions is possible.
The method according to various embodiments thus makes it possible to counteract the excessive overheating of the foot-well by the air-conditioning system when the top is open. The distribution of the air-mass flow rate or the temperature over the different vent openings 21 and 22 can be used both in the heating and cooling operations. However, in the present exemplary embodiment, this distribution is selected only in the heating operation since this is where the problem of a possible overheating of the foot-well occurs.
The control units 31, 32, and 33 for the vent openings 21, 22, and 23 supply a specific voltage to several blowers provided for the respective vent openings 21, 22, and 23. This voltage controls the blower power. When the top is open, the regulation of the air-conditioning system tends to select a very high air-mass flow rate in order to compensate for the increased exchange of energy between the passenger compartment and the outside ambience. Although a high blower power results in a high air-mass flow rate through the respective vent opening 21, 22 or 23, it also results in a high sound volume of the blower in the passenger compartment, which can be an acoustic nuisance for the passengers. In order to prevent the same, when the top is open, that basic blower voltage characteristic regulating the blower power is selected that is lowered compared to the basic blower voltage characteristic when regulating the air-conditioning system with the top closed. This helps reduce the noise nuisance caused by the blower of the air-conditioning system when the top is open.
In addition, a characteristic is stored in the central control unit 1, which characteristic contains the blower noise as a function of the blower power and the airflow noise, which occurs independently of the blower when the top is open, as a function of the traveling speed. With the help of this characteristic, a limit value is determined for the blower power. This limit value is selected in such a way that the blower noise does not exceed the other airflow noise. The blower power is thus limited as a function of the vehicle speed, and the limit value depends on the sound volume of the blower.
Furthermore, when the top is open, the influence of those measured values for the solar radiation that are transmitted to the central control unit 1 by sensors 71 and 72 is changed. When the top is open, the influence of the solar radiation as a control variable is increased. Simultaneously, the time constant indicating the rate at which the regulation of the air-conditioning system reacts to changes in the solar radiation is reduced.
When the top is closed, different zones of the passenger compartment are air-conditioned variably depending on how the measured values for the solar radiation turn out at different positions. This situation changes when regulating the air-conditioning system with the top is open. In this case, the highest value for the solar radiation is used as the control variable for regulating the air-conditioning system. This value then applies to all zones of the passenger compartment, i.e., both on the right and left sides of the passenger compartment.
Furthermore, the central control unit 1 changes the calculation of the value for the actual temperature of the passenger compartment for regulating the air-conditioning system. When the top is closed, the measured value of the temperature sensor 5 of the passenger compartment is directly used as the value for the actual temperature of the passenger compartment when regulating the air-conditioning system. When the top is open, that value for the actual temperature of the passenger compartment that is used for regulating the air-conditioning system is calculated from the measured value of the temperature sensor 5 of the passenger compartment and the measured value of the outside temperature sensor 6. The value for the actual temperature of the passenger compartment is composed of defined fractions of the measured value of the temperature sensor 5 of the passenger compartment and the measured value of the outside temperature sensor 6. For example, it is possible to take into consideration 70% of the measured value of the temperature sensor 5 of the passenger compartment and 30% of the measured value of the outside temperature sensor 6.
Finally, the regulation of the air-conditioning system relates to the transition of the regulation when the top is closed to the regulation when the top is open and vice versa. For this purpose, the sensor 8 indicates to the central control unit 1 whether the top is open or closed. During the opening or closing of the top, intermediate values of the regulating parameters for the open and closed states of the top are used when regulating the air-conditioning system. However, the transition from the open to the closed states of the top and vice versa does not take place linearly. Instead, the intermediate values approximate to the regulating parameters for an open top faster during the opening of the top than the rate at which the intermediate values approximate to the regulating parameters for a closed top during the closing of the top. For example, when opening the top, the intermediate values approximate to the regulating parameters for an open top faster than in the case of a linear approximation. In contrast, when closing the top, the intermediate values approximate to the regulating parameters for a closed top more slowly than in the case of a linear approximation. Thus, when opening the top, the regulating parameters for the open top are already reached although the top is not yet completely open. On the other hand, when closing the top there occurs a more gentle transition to the regulating parameters for a closed top so that the regulating parameters for the closed top are reached only when the top is already closed.

LIST OF REFERENCE NUMERALS

1 Central control unit
21, 22, Vent openings
23
31, 32, Control units for the vent openings
33
4 Input device
5 Temperature sensor for the passenger compartment
6 Outside temperature sensor
71, 72 Sensors for the solar radiation in different positions
8 Sensor for detecting the state of the top
9 Speed sensor

Claims

1. Method for regulating an air-conditioning system of a vehicle whose top can be opened, the method comprising the steps of:

regulating air temperature and mass flow rate as a function of at least the control variables of a setpoint temperature of a passenger compartment and an actual temperature of the passenger compartment being fed to a passenger compartment of the vehicle via a plurality of vent openings wherein the regulating parameters used for regulating the air-conditioning system when the top is open are different from those used when the top is closed,

using intermediate values of the regulating parameters during the opening and closing of the top, wherein the intermediate values approximate to the regulating parameters for an open top faster during the opening of the top than the rate at which the intermediate values approximate to the regulating parameters for a closed top during the closing of the top.

2. The method according to claim 1, wherein the speed of the vehicle is determined and, as the speed of the vehicle increases, the air-mass flow rate, which is fed to the passenger compartment through vent openings at lower positions, is reduced or the air-mass flow rate, which is fed to the passenger compartment through vent openings at higher positions is increased, or as the speed of the vehicle increases, the air-mass flow rate is increasingly shifted from the vent openings for the foot-well of the passenger compartment at lease to vent openings selected from the group consisting of vent openings for the torso, the hands and the forearms of the passengers.

3. The method according to claim 1, wherein the temperature of the air fed to the passenger compartment is higher than the actual temperature of the passenger compartment.

4. The method according to claim 1, wherein the air-mass flow rate is conveyed via a blower, whose power is regulated by means of a basic blower voltage characteristic, and the basic blower voltage characteristic is lowered compared to the basic blower voltage characteristic when regulating the air-conditioning system with the top closed.

5. The method according to claim 1, wherein the air-mass flow rate is conveyed via a blower and the blower power is limited as a function of the vehicle speed and the limit value depends on the sound volume of the blower.

6. The method according to claim 5, wherein, the limit value is selected in such a way that the blower noise does not exceed the airflow noise.

7. The method according to claim 5, wherein the airflow noise is measured.

8. The method according to claim 5, wherein the airflow noise is determined in advance and the limit value for the blower power is selected by means of a characteristic, which contains the blower noise as a function of the blower power as well as the airflow noise as a function of the traveling speed.

9. The method according to claim 1, wherein the solar radiation hitting the passenger compartment is measured and the measured values of the solar radiation constitute another control variable for regulating the temperature or the mass flow rate of the air fed to the passenger compartment, the influence of the measured values of the solar radiation when the top is open being stronger than the influence of the measured values of the solar radiation when regulating the air-conditioning system with the top closed.

10. The method according to claim 9, wherein the solar radiation is measured in at least two positions and differences in the measured values in different positions are not considered when regulating the temperature or the mass flow rate of the air fed to the passenger compartment.

11. The method according to claim 1, wherein the value for the actual temperature of the passenger compartment, which value is used when regulating the air-conditioning system, is calculated from the measured value of a temperature sensor of the passenger compartment and the measured value of an outside temperature sensor.

12. The method according to claim 2, wherein the air-mass flow rate changes over a plurality of steps or continuously as the speed of the vehicle increases.

13. The method according to claim 12, wherein air-mass flow rate changes inversely when the vehicle speed returns to a lower level.

14. The method according to claim 1, wherein the speed of the vehicle is determined and, as the speed of the vehicle increases, the air-mass flow rate, which is fed to the passenger compartment through vent openings at lower positions, is reduced and the air-mass flow rate, which is fed to the passenger compartment through vent openings at higher positions is increased, or as the speed of the vehicle increases, the air-mass flow rate is increasingly shifted from the vent openings for the foot-well of the passenger compartment at least to vent openings selected from the group consisting of vent openings for the torso, the hands and the forearms of the passengers.

15. The method according to claim 1, wherein the solar radiation hitting the passenger compartment is measured and the measured values of the solar radiation constitute another control variable for regulating the temperature and the mass flow rate of the air fed to the passenger compartment, the influence of the measured values of the solar radiation when the top is open being stronger than the influence of the measured values of the solar radiation when regulating the air-conditioning system with the top closed.

16. The method according to claim 15, wherein the solar radiation is measured in at least two positions and differences in the measured values in different positions are not considered when regulating the temperature and/or the mass flow rate of the air fed to the passenger compartment.

17. The method according to claim 2, wherein the temperature of the air fed to the passenger compartment is higher than the actual temperature of the passenger compartment and the air-mass flow rate changes over a plurality of steps or continuously as the speed of the vehicle increases.

18. The method according to claim 17, wherein the air-mass flow rate changes inversely when the vehicle speed returns to a lower level.

19. The method according to claim 14, wherein the temperature of the air fed to the passenger compartment is higher than the actual temperature of the passenger compartment and the air-mass flow rate changes over a plurality of steps or continuously as the speed of the vehicle increases.

20. The method according to claim 19, wherein the air-mass flow rate changes inversely when the vehicle speed returns to a lower level.