Method for operating a parking heater system for a vehicle

Abstract

A method for operating a parking heater system for a vehicle, wherein the parking heater system (10) comprises a heater (12) and a heat exchanger arrangement (14) for transferring heat to air (H) to be introduced into a vehicle interior (16), a fresh air / recirculated air switching arrangement (20) for selectively supplying fresh air (F) or recirculated air (U) or a fresh air / recirculated air mixture to the heat exchanger arrangement (14), and a control arrangement (22) for controlling the heater (12) and the fresh air / recirculated air switching arrangement (20), wherein in the method, in a first operating phase following the start of the heater (12), essentially recirculated air (U) is supplied to the heat exchanger arrangement (14), and in a second operating phase following the first operating phase, essentially fresh air (F) or fresh air (F) and recirculated air (U) is supplied to the heat exchanger arrangement (14), characterized in that then,If, in the second operating phase, a fresh air / recirculated air mixture is supplied, the proportion of fresh air is adjusted depending on the humidity in the vehicle interior (16) and in the vehicle's surroundings, such that when the humidity in the vehicle interior (16) is higher than in the vehicle's surroundings, a higher proportion of fresh air is used, and when the humidity in the vehicle interior (16) is lower than in the vehicle's surroundings, a lower proportion of fresh air is used.

Description

[0001] The present invention relates to a method for operating a parking heater system for a vehicle, as well as to a parking heater system. Such a parking heater system is generally constructed with a heater in which thermal energy is provided, for example, through combustion or electrical excitation. In a heat exchanger arrangement, thermal energy provided in the heater can be transferred to the air to be introduced into a vehicle interior. This transfer can occur directly or by means of a heat transfer medium, for example the coolant also present in the cooling circuit of an internal combustion engine. Such a parking heater system further comprises a fresh air / recirculated air switching arrangement, which can be used, for example, when a vehicle is moving, through appropriate manual interaction to either introduce fresh air into the interior or recirculate air in a recirculation mode.In order to specify the operation of various system components of the auxiliary heating system, for example the heater and the fresh air / recirculating air switching arrangement, a control arrangement is provided which, for example, also adjusts the operation of the heater or the fresh air / recirculating air switching arrangement according to the existing requirements based on various information supplied to it, such as ambient temperature or vehicle interior temperature.

[0002] A method for operating a parking heater system for a vehicle according to the preamble of claim 1 is known from DE 101 10 558 A1. In this known method, when a heater is switched on, the system switches to a "recirculating air" operating mode, in which only recirculating air extracted from the vehicle interior is heated. For example, when a predetermined temperature is reached in the vehicle interior, the "recirculating air" operating mode is ended and the system switches to a "ventilating" operating mode, in which fresh air heated by the vehicle heater is supplied to the vehicle interior.

[0003] It is the objective of the present invention to provide a method for operating a parking heater system for a vehicle or a parking heater system with which the desired conditioning of a vehicle in parking heater operation can be achieved as quickly as possible.

[0004] According to the present invention, this object is achieved by a method for operating a parking heater system for a vehicle according to claim 1. The parking heater system comprises a heater and a heat exchanger arrangement for transferring heat to air to be introduced into a vehicle interior, a fresh air / recirculated air switching arrangement for selectively supplying fresh air or recirculated air or a fresh air / recirculated air mixture to the heat exchanger arrangement, and a control arrangement for controlling the heater and the fresh air / recirculated air switching arrangement. In the method, in a first operating phase following the start of the heater, the heat exchanger arrangement is supplied with essentially recirculated air, and in a second operating phase following the first operating phase, the heat exchanger arrangement is supplied with essentially fresh air or fresh air and recirculated air.

[0005] In this process, after the heater has been switched on, the recirculated air, i.e. the air drawn from the vehicle interior, is initially used in circulation mode in order to achieve the fastest possible temperature rise in the vehicle interior. This assumes that generally, even at comparatively low ambient temperatures, the temperature inside a vehicle interior will be somewhat higher than the temperature outside the vehicle, particularly when exposed to sunlight. After transitioning to the second operating phase, fresh air or fresh air is then fed to the heat exchanger arrangement, which means that at least part of the recirculated air drawn from the vehicle interior is released to the outside. This ensures that more of the moisture contained in the air in the vehicle interior is removed from the vehicle interior.

[0006] For this purpose, for example, only fresh air can be supplied to the heat exchanger arrangement in the second operating phase, so that the air present in the vehicle interior, which may have a high moisture content, is exchanged as quickly as possible.

[0007] If, in the second operating phase, a fresh air / recirculated air mixture is fed to the heat exchanger arrangement, which also means that part of the recirculated air extracted from the vehicle interior is no longer fed back into the vehicle interior, the proportion of fresh air is adjusted according to the humidity in the vehicle interior and in the vehicle's surroundings in order to improve the quality of a vehicle's pre-conditioning, which also depends on the condition of the vehicle itself. By taking humidity into account, in particular relative humidity, it is possible to ensure that the air in the vehicle interior does not have an excessively high moisture content when the vehicle is used, thus preventing fogging of windows, but is also not too dry, for example, and is therefore perceived as pleasant for occupants of the vehicle interior.For this purpose, if the humidity in the vehicle interior is higher than in the surroundings of the vehicle, a higher proportion of fresh air is used, and if the humidity in the vehicle interior is lower than in the surroundings of the vehicle, a lower proportion of fresh air is used.

[0008] In a further variant, it can be provided that, in the second operating phase of the heat exchanger arrangement, fresh air is supplied during fresh air supply intervals and recirculated air is supplied during recirculated air supply intervals, with the fresh air supply intervals and the recirculated air supply intervals alternating with one another. In this case, operation is thus cyclically controlled, with the fresh air supply intervals comprising at least one such interval, and the recirculated air supply intervals likewise comprising at least one such recirculated air supply interval, but preferably switching between the two operating modes takes place repeatedly.

[0009] Furthermore, in order to increase the quality of the preconditioning, it can be provided that in the second operating phase the proportion of fresh air is adjusted depending on the air quality, preferably depending on the atmospheric oxygen content, in the vehicle interior. For example, the procedure can be such that when the atmospheric oxygen content in the vehicle interior is higher, a lower proportion of fresh air is used, and when the atmospheric oxygen content in the vehicle interior is lower, a higher proportion of fresh air is used. This means that, for example, via an inversely proportional relationship between the atmospheric oxygen content and the fresh air content, more fresh air is supplied to the vehicle interior when there is a greater oxygen demand, i.e. a lower oxygen content, than in a state in which the air in the vehicle interior already has a comparatively high oxygen content, i.e. a low oxygen demand.

[0010] To initiate the transition to the second operating phase, a predetermined time period can be stored in the control arrangement. This time period is intended for the first operating phase. The expiration of this time period then leads to the initiation of the second operating phase through appropriate control of the fresh air / recirculated air switching arrangement. For example, a fixed time period of 5 minutes can be used here. However, it is also generally possible to select the time period over which the first operating phase is carried out depending on the ambient conditions, such as the outside temperature, the temperature inside the vehicle, the air humidity outside the vehicle, or the air humidity inside the vehicle.

[0011] When the vehicle is then put into operation, essentially only fresh air is supplied during the second operating phase to ensure a sufficient oxygen content. Of course, this control specification can be overridden by a user. The start-up of a vehicle can be defined based on various parameters, such as unlocking a vehicle door, a driver sitting in the driver's seat, starting a drive unit, especially an internal combustion engine, or the like.

[0012] The present invention will be described below with reference to the attached Fig. 1 is described in detail. This shows a schematic diagram of a parking heating system for a vehicle.

[0013] The Fig.The auxiliary heating system 10 shown in Figure 1 comprises, as an essential component, a heater 12, which may, for example, be fuel-operated, i.e., has a combustion chamber supplied with fuel and combustion air, in which hot combustion exhaust gases are generated. Of course, the heater 12 could also be electrically excitable, for example, comprising a plurality of PTC heating elements.

[0014] In a heat exchanger arrangement 14, the heat provided in the heater 12 is transferred to the air to be introduced into a vehicle interior 16. This air is introduced by a fan 18 from a fresh air / recirculated air switching arrangement 20 via the heat exchanger arrangement 14 into the vehicle interior 16 as heated air H. The recirculated air U extracted from the vehicle interior 16 flows back to the fresh air / recirculated air switching arrangement 20, where, depending on its operating position, it is discharged to the outside as exhaust air A or is conveyed towards the heat exchanger arrangement 14 for reheating and introduction into the vehicle interior 16 as heated air H. Of course, only a portion of the recirculated air U can be discharged to the outside as exhaust air A, in which case fresh air F replaces the discharged portion and is conveyed to the heat exchanger arrangement 14 together with the reused portion of recirculated air.This means that the fresh air / recirculating air switching arrangement 20 can in principle be designed such that it either only directs recirculating air U to the heat exchanger arrangement 14 or only directs fresh air F to the heat exchanger arrangement 14 or directs a mixture of recirculating air U and fresh air F to the heat exchanger arrangement 14.

[0015] These switching positions of the fresh air / recirculated air switching arrangement 20 can be predetermined by a control arrangement 22, which can be integrated, for example, into an assembly comprising the heater 12, the heat exchanger arrangement 14, and the fan 18. The control arrangement 22 can also regulate or control the operation of the heater 12 and the fan 18, for example, in order to adjust them depending on ambient conditions, such as the temperature in the vehicle interior 16, the air humidity in the vehicle interior 16, or outside the vehicle. The auxiliary heater operation can, for example, be started at a fixed time or a fixed period of time, which can be varied depending on the ambient conditions, before a vehicle is scheduled to be used.When the heater 12 is put into operation and the heat energy is thus provided to be transferred to the air to be introduced into the vehicle interior 16, the fresh air / recirculated air switching arrangement 20 is initially controlled in a first operating phase in order to heat the vehicle interior 16 as quickly as possible, in such a way that only the recirculated air U previously extracted from the vehicle interior 16 is directed towards the heat exchanger arrangement 14, but no or essentially no fresh air F. In this operating phase, during which the fan 18 is also operated at least from a predetermined period of time after the heater 12 has been started, the system operates in recirculated air mode until, for example, a predetermined period of time after the heater 12 has been started up, a transition to a second operating phase takes place.

[0016] In this context, it should be noted that the coupling of the previously mentioned predetermined time period to the commissioning of the heater 12 can also be achieved by having it only begin running when the fan 18 is started. The basis for this can be that the fan 18 is only activated with a delay after the start of the combustion or heating operation of the heater 12, in order to ensure that sufficiently high temperatures are initially provided in the area of ​​the heater 12 or the heat exchanger arrangement 14 for efficient heat transfer. For the purposes of the present invention, the commissioning of, for example, the fan 18 or any other system component of the heater 12, or possibly also the decommissioning, such as the switching off of a glow plug, is to be understood as a coupling of this time interval or predetermined time period to the start of the heater 12.

[0017] It should also be noted that the predetermined time period can, of course, be fixed and unchangeable, for example, as a time interval of 5 minutes, or can be selected depending on various environmental parameters, such as temperature values ​​inside or outside the vehicle. The air humidity, for example, in the vehicle interior 16 or outside the vehicle, can also be used to select this time period, after which the system transitions to the second operating phase.

[0018] In the second operating phase, the system transitions from pure recirculation mode to an operating mode in which fresh air is at least partially added to the air supplied to the heat exchanger arrangement 14. This can be achieved, for example, by directing only fresh air F to the heat exchanger arrangement 14 during the transition to the second operating phase, while the recirculation air U extracted from the vehicle interior 16 is essentially completely discharged to the outside as exhaust air A. It is also possible to combine the heating air H as a mixture of recirculation air U and fresh air F in order to gradually exchange the air present in the vehicle interior 16 at the start of the auxiliary heating operation.In this way, the vehicle is pre-conditioned in such a way that a very high proportion of fresh air is present in the vehicle interior 16 upon commissioning, while at the same time it can be ensured that the moisture contained in the air originally present in the vehicle interior 16 is removed by the gradual exchange with fresh air F. If it is determined by comparing the air humidity, for example the relative air humidity, in the vehicle interior 16 and in the surroundings of the vehicle that the ambient air has a lower air humidity, then a higher proportion of fresh air or exclusively fresh air F is used, whereas if the air humidity in the air initially present in the vehicle interior 16 is lower, the proportion of fresh air is kept lower. It goes without saying that in order to record the air humidity, in particular the relative air humidity, orAppropriate humidity sensors are also provided inside or outside the vehicle interior to compare the previously mentioned air humidity levels.

[0019] Furthermore, in the second operating phase, in order to gradually increase the proportion of fresh air in the vehicle interior 16, it is possible to switch between fresh air supply intervals and recirculated air supply intervals, in which essentially only fresh air or essentially only recirculated air is fed to the heat exchanger arrangement 14, i.e. the fresh air / recirculated air switching arrangement 20 is switched alternately. The duration of the intervals can, for example, again be adjusted depending on the ambient conditions, for example the humidity contained in the air. Here, too, it is possible to work with shorter fresh air supply intervals compared to the recirculated air supply intervals when the air humidity outside the vehicle is comparatively higher, or with correspondingly longer fresh air supply intervals and shorter recirculated air supply intervals when the air humidity outside the vehicle is comparatively lower.In this way, a comparatively rapid heating of the vehicle interior 16 is achieved while at the same time gradually increasing the proportion of fresh air.

[0020] Finally, it should be noted that other parameters, such as the air quality, for example the oxygen content of the air present in the vehicle interior 16, can also be used to select the proportion of fresh air or the proportion of recirculated air. The higher the oxygen content, the greater the proportion of recirculated air used in the second operating phase can be, which contributes to a reduction in the proportion of the comparatively colder fresh air F and a correspondingly faster heating of the vehicle interior 16. In order to be able to detect the oxygen content in the air present in the vehicle interior, an oxygen sensor can be provided in the vehicle. It should be noted here that, of course, other variables indicating the air quality in the vehicle interior, such as the nitrogen content or the like, can also be taken into account orcan be recorded accordingly by sensors and then used to optimize air quality in the second operating phase in order to adjust the proportion of fresh air accordingly to improve air quality.

[0021] If the vehicle is then actually put into operation, for example if a vehicle door is unlocked, a driver's seat is occupied or a drive unit, such as an internal combustion engine, is started, it is possible to switch to a mode in which only fresh air F is supplied in order to ensure a sufficient oxygen content for the person then located in the vehicle interior 16.

[0022] It should be noted that the previously explained structure of the heating system, particularly in the area of ​​the heater 12, the heat exchanger arrangement 14, and the fan 18, is only in principle and by way of example to explain the present invention. A wide variety of variations could be envisaged here. For example, a liquid heat transfer medium, such as the coolant provided in the coolant circuit of an internal combustion engine, could be heated by means of the heater 12, which can then transfer the heat transported therein in the heat exchanger arrangement 14 to the air to be introduced into the vehicle interior. In a pure air heater, however, this heat transfer can also take place directly from the heater 12 in the heat exchanger arrangement 14 to the air to be introduced into the vehicle interior.

Claims

[1] A method for operating a parking heating system for a vehicle, wherein the parking heating system (10) comprises a heater (12) and a heat exchanger arrangement (14) for transferring heat to air (H) to be introduced into a vehicle interior (16), a fresh air / recirculating air switching arrangement (20) for selectively supplying fresh air (F) or recirculating air (U) or a fresh air / recirculating air mixture to the heat exchanger arrangement (14), and a control arrangement (22) for controlling the heater (12) and the fresh air / recirculating air switching arrangement (20), wherein, in the method, in a first operating phase following the start of the heater (12), substantially recirculating air (U) is supplied to the heat exchanger arrangement (14), and in a second operating phase following the first operating phase, substantially fresh air (F) or fresh air (F) and recirculating air (U) are supplied to the heat exchanger arrangement (14). characterized bythat when a fresh air / recirculated air mixture is supplied in the second operating phase, the proportion of fresh air is adjusted as a function of the air humidity in the vehicle interior (16) and in the surroundings of the vehicle, such that when the air humidity in the vehicle interior (16) is higher than in the surroundings of the vehicle, a higher proportion of fresh air is used, and when the air humidity in the vehicle interior (16) is lower than in the surroundings of the vehicle, a lower proportion of fresh air is used. [2] Method according to claim 1, characterized by that in the second operating phase of the heat exchanger arrangement (14) only fresh air (F) is supplied. [3] Method according to claim 1 or 2, characterized bythat in the second operating phase of the heat exchanger arrangement (14) fresh air (F) is supplied in fresh air supply intervals (F) and recirculated air (U) is supplied in recirculated air supply intervals, wherein the fresh air supply intervals and the recirculated air supply intervals alternate with one another. [4] Method according to one of claims 1 to 3, characterized by that in the second operating phase the proportion of fresh air is adjusted depending on the air quality, preferably depending on the atmospheric oxygen content, in the vehicle interior (16). [5] Method according to claim 4, characterized by that when the atmospheric oxygen content in the vehicle interior (16) is higher, a lower proportion of fresh air is used, and when the atmospheric oxygen content in the vehicle interior (16) is lower, a higher proportion of fresh air is used. [6] Method according to one of claims 1 to 5, characterized bythat the transition to the second operating phase occurs a predetermined period of time after the heater (12) has started. [7] Method according to one of claims 1 to 6, characterized by that from the start of operation of a vehicle, the heat exchanger arrangement (14) is supplied with essentially fresh air (F).

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