Method, control device and computer program product for controlling a room climate in the interior of a motor vehicle

Abstract

Method for controlling a room climate in an interior (10) of a motor vehicle, in which a CO2 concentration is determined in the interior (10), a recirculation requirement for recirculating air from the interior (10) is determined, the determined CO2 concentration is compared with a long-term threshold value and in the event that the CO2 concentration exceeds the long-term threshold and at the same time there is a recirculation requirement to recirculate air from the interior (10), an increase in the proportion of fresh air in the interior (10) is only initiated when the CO2 concentration exceeds a short-term threshold value that is above the long-term threshold value and / or remains above the long-term threshold value for a predetermined delay period remains.

Description

[0001] The invention relates to a method, a control device and a computer program product, with the aid of which a room climate in the interior of a motor vehicle can be controlled.

[0002] From DE 10 2006 003 071 A1 it is known to measure a CO2 concentration in the interior of a motor vehicle and to automatically supply fresh air from outside if the measured CO2 concentration exceeds a threshold value.

[0003] From DE 10 2015 214 307 A1 it is known to trigger different safety measures in the event of a leakage of CO2 from a refrigerant circuit into the interior of a motor vehicle when different threshold values ​​for the measured CO2 concentration in the interior are reached, whereby when the lowest threshold value for the measured CO2 concentration is reached, the recirculation mode of an air conditioning system is stopped and fresh air is supplied as a safety measure.

[0004] From DE 197 20 293 C1 it is known to stop the recirculation mode of an air conditioning system and supply fresh air when a threshold value for a measured CO2 concentration in the interior of a motor vehicle is exceeded.

[0005] There is a constant need to ensure a good indoor climate in the interior of a motor vehicle.

[0006] The object of the invention is to show measures that enable a good indoor climate in the interior of a motor vehicle.

[0007] The object is achieved according to the invention by a method having the features of claim 1, a control device having the features of claim 9 and a computer program product having the features of claim 10. Preferred embodiments of the invention are specified in the subclaims and the following description, which may each individually or in combination represent an aspect of the invention.

[0008] One aspect of the invention relates to a method for controlling a room climate in an interior of a motor vehicle, in which a CO2 concentration in the interior is determined, a recirculation requirement for recirculating air from the interior is determined, the determined CO2 concentration is compared with a long-term threshold value and, in the event that the CO2 concentration exceeds the long-term threshold value and, at the same time, a recirculation requirement for recirculating air from the interior exists, an increase in the proportion of fresh air in the interior is only initiated when the CO2 concentration exceeds a short-term threshold value that is above the long-term threshold value and / or remains above the long-term threshold value for a predetermined delay period.

[0009] The long-term threshold can represent a CO2 concentration threshold up to which a person can be exposed for an extended period, for example, over twelve hours, without significant adverse effects on well-being and concentration. However, it has been recognized that impairments caused by a CO2 concentration above the long-term threshold only become noticeable much later. Instead of immediately supplying fresh air to the vehicle's interior when the long-term threshold for the CO2 concentration is exceeded, the long-term threshold is deliberately allowed to be exceeded. Often enough, the CO2 concentration subsequently drops, making control intervention unnecessary.A control intervention regarding the supply of fresh air only takes place if the CO2 concentration remains above the long-term threshold value over the delay period and / or the CO2 concentration has reached such a high concentration that the short-term threshold value for the CO2 concentration, which is significantly higher than the long-term threshold value, is also exceeded.

[0010] This allows for consideration of the fact that the supply of fresh air is prevented or reduced for good reasons. For example, the fresh air can introduce unpleasant odors into the vehicle's interior, so that in this situation, a temporary but harmless increase in the CO2 concentration above the long-term threshold is more acceptable than the supply of odorous fresh air. Manually setting the recirculation request to a state with an increased proportion of recirculated air from the interior ("recirculated air") and a reduced proportion of fresh air, or completely interrupting the supply of fresh air, will not be immediately canceled if the CO2 concentration exceeds the long-term threshold.It is also possible that an increased particulate matter load in the fresh air has been detected, resulting in an automatic adjustment of the recirculation requirement to a state with an increased proportion of recirculated air and a reduced proportion of fresh air, or a complete interruption of the fresh air supply. This adjustment, however, is not immediately canceled if the CO2 concentration exceeds the long-term threshold. Actually conflicting control instructions for the proportion of recirculated air can be balanced by staggering the reduction of recirculated air when the CO2 concentration exceeds the long-term threshold in a manner that is comfortable for the vehicle occupants, thus enabling a good indoor climate in the interior of a vehicle.

[0011] If recirculation is not planned, i.e. the recirculation proportion is zero, there is no recirculation requirement. In this case, the proportion of fresh air in the air supplied to the interior is already at its maximum. If the CO2 concentration exceeds the long-term threshold but there is no recirculation requirement, it can be planned to simply increase the mass flow of the supplied air, for example by increasing the fan power. In this case, the mass flow of the supplied air can be adjusted immediately without waiting for the delay time. If the recirculation proportion is set to zero, there are obviously no impairments caused by the fresh air supplied that should be avoided and / or reduced by waiting for the delay time.The recirculation requirement can be the result of a calculation performed in a computer unit, in which various values, such as measured values ​​and / or estimated values, are taken into account on the basis of at least one requirement determination model in order to adjust at least one parameter influencing the proportion of recirculated air and fresh air in the air supplied to the interior. The recirculation requirement can indicate whether a non-zero proportion of recirculated air is provided in the air supplied to the interior, whereby the proportion of recirculated air in the air supplied to the interior can be quantified from at least one parameter used for this purpose.

[0012] In particular, the increase in the proportion of fresh air in the interior is achieved by changing parameters of the recirculated air request. The control intervention required to increase the proportion of fresh air in the interior can be implemented by at least temporarily overwriting one or more parameters in the recirculated air request. For example, a parameter for a proportion of recirculated air to be controlled in the air conditioning of the interior and / or a parameter for a mass flow of fresh air into the interior to be controlled can be changed in order to be able to reduce the excessive CO2 concentration. This makes it possible to carry out control intervention in just one component of the motor vehicle, which can also be carried out without mechanical coupling with electronically transmittable signals, in order to bring the CO2 concentration in the interior to a value below the long-term threshold.This means that the construction effort can be kept to a minimum.

[0013] Preferably, in the event that the CO2 concentration exceeds the long-term threshold, a previous, particularly user-defined, setting for the recirculation request is disregarded until the determined CO2 concentration is below the long-term threshold. If the CO2 concentration is below the long-term threshold, in particular by a predefined margin from the long-term threshold, the recirculation request parameters provided before the control intervention can be restored. If the short-term threshold is exceeded and / or the delay period has expired, the settings of the control intervention made in this case dominate over the other control requests, at least until the CO2 concentration falls below the long-term threshold.

[0014] Particularly preferably, the recirculation request comprises setting a pivot angle of a recirculation flap, wherein the set pivot angle is dependent on a user setting and / or a determined particulate matter concentration in the fresh air and / or an outside temperature of the fresh air, in particular to prevent fogging of a transparent window and / or control an interior temperature of the vehicle, and / or a current driving speed of the motor vehicle. The pivot angle of the recirculation flap can be adjusted manually or automatically. In the event of a control intervention as a result of the long-term threshold value being exceeded too high and / or for too long, the pivot angle of the recirculation flap can be suitably changed so that the necessary control intervention can be implemented by a simple measure.

[0015] In particular, the long-term threshold value and / or the short-term threshold value and / or the delay period are specified as a function of the number of people in the interior and / or the temperature in the interior and / or the opening state of windows that can be opened to the environment and / or the driving speed of the motor vehicle and / or the mass flow of supplied fresh air, in particular with the aid of a controller. In particular, these are a short-term threshold value and a long-term threshold value, the values ​​maintained by a controller. This makes it possible to provide dynamic values ​​for the long-term threshold value and / or the short-term threshold value and / or the delay period, which can take into account at least an estimated gradient of an increase in the CO2 concentration with a high proportion of recirculated air and / or at least an estimated gradient of a decrease in the CO2 concentration with a high proportion of fresh air.

[0016] Preferably, the CO2 concentration is determined as a function of the number of occupants in the vehicle interior, the temperature in the vehicle interior, the opening state of windows that open to the environment, the vehicle speed, and / or the mass flow of supplied fresh air. This makes it possible to eliminate the need for a CO2 sensor for measuring the CO2 concentration. Instead, it is possible to estimate the CO2 concentration with sufficient accuracy based on the physical influencing factors relevant to the CO2 concentration in the vehicle interior and to determine the CO2 concentration without direct measurement.

[0017] Particularly preferably, various requirement determination models based on different parameters are used to determine the recirculated air requirement, wherein the result of the requirement determination model that leads to a maximum recirculated air proportion and / or a minimum fresh air proportion is used for the determined recirculated air requirement. For example, an air conditioning system, a vehicle occupant, and / or a particulate matter sensor, with their respective requirement determination models, can specify different requirements for the recirculated air proportion to be set by the recirculated air requirement. This conflict can be resolved by applying the requirement with the highest recirculated air proportion. The method according to the invention can ensure that the occupants of the motor vehicle are not adversely affected.If control intervention is required due to the long-term threshold being exceeded, the request with the smallest recirculation share can be applied. Alternatively, the highest recirculation share is always used, which is then limited based on CO2 concentration.

[0018] In particular, a recirculation flap is controlled gradually, particularly in accordance with the transfer behavior of a PT1 control element, to adjust a mass flow intended for recirculating air from the interior as the proportion of fresh air in the interior increases. If a control intervention is to be carried out as a result of the long-term threshold being exceeded, the new target value for the recirculation request, in particular a newly adjusted pivot angle of the recirculation flap, is not set abruptly but in a gradual manner. This prevents abrupt behavior of the recirculation flap. The risk that an occupant mistakes the control intervention for a defect that can be prevented is thus reduced, so that the control intervention regarding the increase in the proportion of fresh air is easier for the occupants to accept, as well as more comfortable and completely unobtrusive.

[0019] A further aspect relates to a control device for regulating the indoor climate in the interior of a motor vehicle, wherein the control device is configured to implement the method, which can be designed and developed as described above. Actually conflicting control instructions for the proportion of recirculated air can be balanced in a manner that is comfortable for the occupants of the motor vehicle by staggering the reduction of the recirculated air in the control device when the CO2 concentration exceeds the long-term threshold, thereby enabling a good indoor climate in the interior of a motor vehicle.

[0020] A further aspect relates to a computer program product for regulating a room climate in the interior of a motor vehicle, with program code means stored on a computer-readable data carrier for carrying out the method, which can be designed and further developed as described above, when the computer program product is executed on a data processing device, in particular a control device, which can be designed and further developed as described above. Actually conflicting control instructions for the proportion of recirculated air can be balanced out in a comfortable manner for the occupants of the motor vehicle by staggering the reduction of the recirculated air when the CO2 concentration exceeds the long-term threshold, thereby enabling a good room climate in the interior of a motor vehicle.

[0021] The invention will be explained below by way of example with reference to the accompanying drawings using preferred embodiments, wherein the features presented below can represent an aspect of the invention both individually and in combination. They show: Fig. 1: a schematic representation of the factors influencing the interior climate of a motor vehicle and Fig. 2: a schematic flow diagram of a method for controlling the interior climate in the interior of a motor vehicle from Fig. 1.

[0022] In the Fig. In the interior 10 of a motor vehicle shown in Figure 1, a CO2 concentration in the interior 10 can be influenced by the CO2 concentration and O2 concentration in a mass flow of supplied fresh air 12. The supplied fresh air 12 can displace exhaust air 14 escaping from the interior 10 to the environment, the CO2 concentration and O2 concentration of which essentially correspond to the air in the interior 10. However, it is also possible, for example due to requirements for an air conditioning system, to recirculate air from the interior 10 as recirculated air 16 by feeding the air extracted from the interior 10 back into the interior as recirculated air 16, for example conditioned in an air conditioning system. The CO2 concentration and O2 concentration of the recirculated air 16 essentially corresponds to the air in the interior 10. The CO2 concentration and O2 concentration of the air in the interior 10 can change in particular due to the breathing air 17 of occupants in the interior 10.Since the volume of the interior 10 is known and the extent of the conversion of O2 into CO2 by the breathing air 17 of the occupants depends essentially on the number of occupants, the change in the CO2 concentration in the interior 10 can be determined with sufficient accuracy by estimation even without a CO2 sensor.

[0023] As in Fig.2, after a start 18, a CO2 concentration in the interior 10 can be determined in a first step 20, wherein the determined CO2 concentration is compared in a second step 22 with a long-term threshold value for the CO2 concentration. In addition, in particular simultaneously, in a third step 24, a recirculation request for recirculating the air from the interior 10 is determined. In this case, for example, a set pivot angle of a recirculation flap can be determined, from which the requirement to supply recirculated air 16 to the interior 10 can be determined. If recirculation is not provided, i.e. the recirculation proportion is zero and the recirculation flap is pivoted into the corresponding end position, there is no recirculation request.

[0024] In a fourth step 26, a check is made to determine whether the determined CO2 concentration exceeds the long-term threshold and, at the same time, the recirculation request specifies a recirculation portion. If this is not the case, there is no need to increase the proportion of fresh air 12, so the method can begin again with the start 18. In the other case, there is a need to increase the proportion of fresh air 12 through control intervention. In this case, a fifth step 28 first checks whether a predefined delay period has already expired. If this is not the case, a sixth step 30 checks whether a short-term threshold for the CO2 concentration that is significantly above the long-term threshold has been exceeded.If this is also not the case, a check is carried out again in the fourth step 26 to determine whether the determined CO2 concentration still exceeds the long-term threshold and, at the same time, the recirculation request specifies a recirculation proportion. If this is the case for the entire delay period, or if the short-term threshold is exceeded before the end of the delay period, a control intervention is carried out in a seventh step 32 to increase the proportion of fresh air 12 for the interior. For this purpose, the recirculation is limited, resulting in an increased proportion of fresh air. In a subsequent eighth step 34, a check is carried out to determine whether the CO2 concentration falls below the long-term threshold. As long as this is not the case, the control intervention remains in place or is even intensified.If the CO2 concentration falls below the long-term threshold by a predefined amount, the control intervention can be withdrawn in a ninth step 36, and the parameters specified before the control intervention can be restored. The process can then be repeated with the start 18.

Claims

[1] Method for controlling the climate in an interior space (10) of a motor vehicle, wherein a CO2 concentration in the interior (10) is determined, a recirculation requirement for recirculating air from the interior (10) is determined, the determined CO2 concentration is compared with a long-term threshold value and in the event that the CO2 concentration exceeds the long-term threshold and at the same time there is a recirculation requirement to recirculate air from the interior (10), an increase in the proportion of fresh air in the interior (10) is only initiated when the CO2 concentration exceeds a short-term threshold above the long-term threshold and / or remains above the long-term threshold for a specified delay period remains. [2] Method according to claim 1, wherein the increase in the proportion of fresh air in the interior (10) is carried out by changing parameters of the recirculation requirement. [3] Method according to claim 1 or 2, wherein, in the event that the CO2 concentration exceeds the long-term threshold, a previous, in particular, user-specific, setting for the recirculation requirement is disregarded until the determined CO2 concentration is below the long-term threshold. [4] Method according to one of claims 1 to 3, wherein the recirculation request comprises setting a swivel angle of a recirculation flap, wherein the set swivel angle depends on a user setting and / or a determined fine dust concentration in the fresh air (12) and / or an outside temperature of the fresh air (12), in particular to prevent fogging of a transparent window and / or to control an interior temperature of the interior (10), and / or a current driving speed of the motor vehicle. [5] Method according to one of claims 1 to 4, wherein the long-term threshold and / or the short-term threshold and / or delay period is specified depending on the number of persons in the interior (10) and / or the temperature in the interior (10) and / or an opening state of windows that can be opened to the environment and / or a driving speed of the motor vehicle and / or a mass flow of supplied fresh air (12), in particular on the basis of a stored characteristic map or with the aid of a controller. [6] Method according to one of claims 1 to 5, wherein the CO2 concentration is determined as a function of the number of persons in the interior (10) and / or the temperature in the interior (10) and / or the opening state of windows that can be opened to the environment and / or the driving speed of the motor vehicle and / or the mass flow of supplied fresh air (12), in particular on the basis of a stored characteristic map or with the aid of a controller. [7] Method according to any one of claims 1 to 6, wherein different requirement determination models based on different parameters are applied to determine the recirculation requirement, wherein the result of the requirement determination model that leads to a maximum high recirculation rate and / or a minimum fresh air rate is used for the determined recirculation requirement. [8] Method according to any one of claims 1 to 7, wherein a recirculation flap for adjusting a mass flow intended for recirculating air from the interior (10) is gradually controlled, in particular according to the transfer behavior of a PT1 control element, when the proportion of fresh air in the interior space (10) is increased. [9] Control device for regulating a room climate in an interior (10) of a motor vehicle, wherein the control device is configured to carry out the method according to one of claims 1 to 8. [10] Computer program product for controlling a room climate in an interior (10) of a motor vehicle, comprising program code means stored on a computer-readable data carrier to carry out the method according to any one of claims 1 to 8, when the computer program product is executed on a data processing device, in particular a control device according to claim 9.

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