DE19643492A1 - Air drying system for vehicle air conditioner - Google Patents

Abstract

Air admitted to the vehicle interior passes through a reactor unit, containing absorption material, at intervals depending upon the temperature of the input air. The energy requirement is calculated by reference to the heat recovery from the vehicle power unit and an electrical heater provides the residual heat required. A fan (2) draws air from the vehicle interior (1) through a duct (3) and outside air through a duct (9) and is controlled by a flap (4) to enter ducts (5) or (10) to be heated by the vehicle water cooling flow or additional heating unit (8). A drying reactor (12) is in the alternative air stream (10') which is controlled by another deflector (11). The air flow may also be directed through a heating unit (17,18). A further deflector (15) directs the dry heated air back to the vehicle interior or the outside. The circulated air may also be cooled (19).

Description

The invention relates to a method for desorbing a in a motor vehicle heating and / or air conditioning system ordered reactor in the preamble of claim 1 given genus as well as a heating or air conditioning system a desorbable reactor in the preamble of An say 1 specified genus.

DE 44 08 796 A1 describes a method for desorption egg described reactor using a hot air stream. A partial air flow is initially in a heating device tion heated before this hot air enters the reactor occurs. The heating can be from one of the waste heat from an on engine powered heat exchanger or an electric Resistance heating, especially with PTC elements. The warm air takes in the sorption material materials such as moisture, and the Airflow leaving the reactor is released into the ambient air blow.

DE 44 14 595 A1 describes a heating and / or air conditioning system Plant known for a motor vehicle interior, the one heating operated by the waste heat of a drive unit has facility. In addition, a reactor is a Contains sorption material to dehumidify the strength Air supplied to the vehicle interior. So that  Reactor can be regenerated are means of desorption of the reactor provided, which comprises at least one heater sen.

The use of waste heat for the desorption process leads Although an inexpensive process, we must inadequate in modern vehicle drives the amount of available heat energy from the waste heat incomplete desorption and / or very long desorp be accepted. For pollution filters and / or dehumidifiers with only one reactor, the working in discontinuous operation, however, it is required an at least almost complete desorption to be carried out within a predetermined desorption time. This problem can be caused by electrical resistance tongue to be solved according to the above pressure writing instead of the heating device using the waste heat is provided. The electrical resistance heater is of the mode of operation of the vehicle drive and there independent in the case of waste heat, but it is disadvantageous that only limited electrical energy in motor vehicles is available and basically on one if possible economical use of this - relatively expensive produced - Energy needs to be respected.

The present invention is therefore based on the object de, a process for the desorption of a reactor in the The preamble of claim 1 specified species to sheep fen, in which an at least approximately complete desorp tion within a predefined desorption time is possible. There is also a heating and / or air conditioning to create a system with which such a process is feasible.  

This task is accomplished by a desorption method in a motor vehicle heating and / or air conditioning system ordered reactor with the features of claim 1 and be regarding the heating or air conditioning system through the features of claim 9 solved.

The main advantages of the invention can be found therein hen that the thermal energy required for the desorption a substantial part or, if necessary, complete due to the existing waste heat from the drive components of the Motor vehicle is won and only the remaining need the required desorption energy from the electrical Vehicle electrical system is removed. Since this remaining need under Zugrun assignment of several parameters can be determined exactly, unnecessary use of energy is avoided. this leads to ultimately a reduction in driving operating costs stuff.

The thermal energy to provide the so-called basic Supply can ge from the exhaust gas of an internal combustion engine be won. Instead of or in addition, the Thermal energy from a gaseous or liquid coolant tel the internal combustion engine can be obtained. It is possible, the heat energy in a heat exchanger directly on the Airflow that the reactor for the purpose of desorption conducts, to transfer, however, alternatively also the heat energy in a heat exchanger on a double transfer medium and by means of this intermediate Carrier medium are led into the reactor.

For the calculation of the desorption energy required several parameters are taken into account, for example the predetermined desorption time, the temperature of the supplied Airflow before it heats up, the temperature of the exhaust  ses of the internal combustion engine, the temperature of the coolant, the humidity of the interior air in the vehicle cabin or the state of loading of the reactor. Depending on the he calculated value for the desorption energy becomes the time point for switching on the additional electrical heating Right. This ensures that the electrical auxiliary tion only in a period of the desorption time is operated, this period of time after the calculated residual demand determined. Depending on certain Parameters, for example full loading of the reak tors, low exhaust gas temperature and the like, the Switching on the additional heating at the beginning of the Desorp tion interval.

So that the heat energy extracted from the waste heat to the reactor can be supplied, optionally one or more heat Meters provided either by a coolant Internal combustion engine or through the hot exhaust gases are cash. The heat exchanger can be designed that a desorption air flow is heated, it can ever but also a liquid heat transfer medium can be used. The least construction effort is achieved in that just a heat exchanger for both vehicle heating as well as for the desorption of the reactor is necessary. For this purpose, it is appropriate that the heat exchanger in one Heating device is arranged by means of an air guide channel directly with the vehicle interior and through an air duct is connected to the reactor where to control the airflow components by the two Air guide channels provided an air flow control element is.

An embodiment of the method according to the invention is explained below with reference to the drawing. In the drawing shows:

Fig. 1 is a schematic representation of a motor vehicle heating system and an air dryer,

Fig. 2 is a diagram of the course of the desorption in the desorption with various Boost time points,

Fig. 3, the desorption temperature heating is a diagram of the course with immediate connection of the electrical accessory,

Fig. 4 is a schematic representation run of a refrigerant circuit,

Fig. 5 shows a variant to Fig. 1,

Fig. 6 is a schematic representation of the input parameters and output signals of a Desorptionsreglers,

Fig. 7 shows an arrangement for heating the desorption air stream by means of the contained in the exhaust Wärmeener energy,

Fig. 8 shows an embodiment of Fig. 7 with a liquid intermediate carrier medium.

In Fig. 1, an air guide duct 3 is connected to a vehicle interior 1 , in which a blower 2 is arranged. The blower 2 is optionally connected on the suction side to an outside air duct 9 , so that both air from the vehicle interior 1 and fresh air can be sucked in. A first air flow control element 4 is located at the end of the air duct 3 and optionally opens an air duct 5 or an air duct 10 . The air guide duct 5 leads to a heating device 8 , in which a heat exchanger, preferably through which an engine coolant flows, is arranged. Downstream of the heater 8 there is an air duct 5 ', which opens into the vehicle interior 1 . In the air duct 5, a second air flow control element 6 is arranged, of which one, the heater 8 of prompt bypass passage 7 leads to the air duct 5 '.

Between the air duct 10 and an air duct section 10 ', which is connected to a reactor 12 , there is a third air flow control element 11 , which selectively directs the air flowing through the air duct 10 to the reactor 12 directly through the section 10 ' or through a desorption duct 16 , in which a heat exchanger 17 and an additional electric heater 18 are arranged, supplies. On the outflow side, an air duct 13 is connected to the reactor 12 , which opens into the air duct 5 upstream of the heating device 8 . From the flow side of the reactor 12 , a fourth air flow control element 15 is provided in the air duct 13 , which connects the reactor 12 to an exhaust air duct 14 , which leads to the ambient air. The reactor 12 can be filled with different sorption material, depending on the desired filter property with regard to pollutants, moisture, etc.

The device shown in FIG. 1 can also be designed as a climate control system, for example by arranging an evaporator 19 of a refrigerant circuit in the air guide duct 5 , shown with dashed lines, between the first air flow control element 4 and the second air flow control element 6 .

Fig. 1 shows the reactor 12 in desorption. Since the first air flow control element 4 is in the position that connects the air duct 3 with the air duct 10 and the third air flow control element 11 closes the section 10 'and releases the desorpti on channel 16 . A hot heat transfer medium, for example the coolant of an internal combustion engine, flows through the heat exchanger 17 and thus heats the desorption air flow which is guided through the desorption channel 16 . According to a calculated value for the desorption energy required, the air flow is heated to its desorption temperature in the electrical auxiliary heater 18 , which preferably comprises an arrangement formed from PTC elements and heat transfer surfaces, and is finally fed to the reactor 12 . The fourth air flow control element 15 closes the air duct 13 and at the same time releases the exhaust air duct 14 , so that the air flow leaving the reactor 12 is blown out into the ambient air.

In Fig. 2 is a diagram of the temperature curve accordingly, the desorption energy E _Des Darge provides in the heat exchanger and the electrical auxiliary heating. This desorption energy E _Des is formed from the sum of the two heating devices, namely

E _Des = E _Wü + E _el .

In this case, as FIG. 2 clearly shows, the heat exchanger, which is operated by means of the on-vehicle exhaust heat from the beginning of the desorption time T _of being added and rising gradually decreased resulting in a temperature variation of 0 and finally asymptotically to the maximum temperature of the heat exchanger T _wü transforms. Depending on the value of the required desorption energy E _Des calculated taking into account several parameters, the additional electrical heating is activated, the connection time t ₁ , t ₂ , t _{3 being determined} according to the required energy E _{el to} be provided by the electrical heating. From the connection point in time t ₁ , t ₂ , t ₃ , the temperature T rises sharply and then approaches the desorption temperature T _Des asymptotically and remains at least approximately constant when the desorption temperature T _{Des is reached} until the predetermined desorption time t _{Des is reached} .

Compared to the temperature profile or energy use with subsequently applied electrical heater switched Fig. 3 shows a diagram in which the electric auxiliary heater is activated simultaneously with the heat exchanger, that is, from the start point 0 in the desorption time t _Des. So far due to any parameters that are taken into account for the calculation of the required desorption energy, a very high residual requirement is determined, a rapid temperature rise above the temperature T _wü can be achieved by the immediate activation of the electrical additional heating, so that the heating rapidly approaches the desorption temperature T _Des . At the end of the predetermined desorption time t _Des , both heaters are switched off.

The connection time t ₁ , t ₂ , t ₃ described in FIG. 2 is variable and is determined in particular by the required desorption temperature, desorption energy, the predetermined desorption time and the temperature of the heat exchanger. In this way, the required desorption tion temperature is achieved with energy-optimized additional heating operation, since the energy potential contained in the waste heat is recovered in the heat exchanger as energy E _Wü and used for the desorption process and only the residual amount of the required desorption energy required in individual cases as electrical heating energy E _el upset who must.

In Fig. 4, a coolant circuit of an engine cooling and vehicle heating is shown schematically. Here, a primary circuit 23 includes an internal combustion engine 40 , which is cooled by the coolant of the primary circuit 23 , a coolant telpump 20 , a radiator 21 and a heating valve 22nd If necessary, a further pump 20 'can be provided in the primary circuit 23 . The radiator 21 is provided for heating the air flow supplied to the passenger compartment and forms the heating device 8 shown in FIG. 1. A secondary circuit 24 is connected to the primary circuit 23 , in which a pump 25 , an additional electrical heater 18 *, a heat exchanger 17 * arranged in the sorption material of the reactor 12 and a valve 26 are arranged. By means of the coolant pump 20, the coolant in the primary circuit 23 is circulated, possibly assisted by the pump 20 '. Depending on the need for a heating power for the air to be introduced into the passenger compartment, the heating valve 22 is controlled. In the desorption mode for the reactor 12 , the pump 25 is activated so that a coolant flow is passed through the heat exchanger 17 *. The valve 26 is of course open in the desorption mode. To complement the heat energy provided by the heat exchanger 17 *, a voltage is applied to the electric auxiliary heater 18 * so that the liquid supplied to the heat exchanger 17 * is brought to a higher temperature level.

Fig. 5 shows a device for heating and drying is of the passenger compartment 1 the air supplied. In this case, a heat exchanger 32 is provided in the heating device 8 , which flows through the coolant of the internal combustion engine, for example. On the secondary side, this heat exchanger 32 is acted upon by a supplied air flow which can be fed to the passenger compartment 1 through an air duct 27 . Parallel to the air duct 27 , another air duct 28 is provided, in which the reactor 12 is net angeord. The control of the respective air flow components through the air guide channels 27 and 28 is carried out by means of an air flow control element 30 . Downstream of the reactor 12 , a further air flow control element 31 is provided, through which the exhaust air duct 14 is closed in the adsorption mode, so that the air dried in the reactor 12 is passed into the vehicle interior 1 . In the desorption operation, the air flow control element 31 is in the position shown in FIG. 5, so that the air leaving the reactor 12 can be blown into the ambient air. The electrical auxiliary heater 18 ** is located in the reactor 12 and preferably comprises a plurality of PTC heating elements. In order to be able to determine the heat energy required by the additional electric heater 18 ** exactly, the temperature of the heat exchanger 32 is detected by means of a temperature sensor 29 .

A control device 33 is shown schematically in FIG. 6, which comprises a microprocessor in which the connection time t ( 1 , 2 , 3 ) is calculated taking into account several input parameters. The required energy E _{el of} the electrical auxiliary heater is calculated as a further output variable. The following parameters are taken into account for the calculation of the values for E _el and t ₍ 1 , 2 , 3 ) as shown in FIG. 6:

Mass flow of desorption air _L ,
Temperature of the heat exchanger T _wü ,
Desorption temperature T _Des ,
Desorption time t _Des
as well as the required desorption energy E _Des .

Various conditions come into consideration for the required desorption energy E _Des , namely the loading state of the dryer, the humidity of the air in the vehicle interior, the temperatures of inside and outside air, specific material values of the sorption material etc.

FIG. 7 shows a reactor 12 with an electrical auxiliary heater 18 ** contained therein, corresponding to the arrangement shown in FIG. 5. The desorption air DL is heated in an exhaust gas heat exchanger 35 , specifically by means of the exhaust gases passed through an exhaust pipe 34 according to arrow A. In this way, the heat is extracted from the exhaust gas of the internal combustion engine and used for the desorption process.

Fig. 8 shows an arrangement in which the exhaust pipe 34 is provided on its outer surface with a coil which serves as a heat exchanger 36 . The heat exchanger 36 is connected to a heat exchanger 37 arranged within the reactor 12 via pipes 38 , a pump 39 being provided for the circulation of the liquid. In addition to the heat exchanger 37 , the electric auxiliary heater 18 ** is located in the reactor 12 .

It is of course also possible to heat both energy of a coolant of the internal combustion engine as well to use the thermal energy of the exhaust gas. Combinations of Systems previously described are therefore quite possible. The greater the proportion of waste heat recovered and as Basic supply for the desorption energy available stands, the lower the required amount of heat energy consumed by the additional electric heating must be brought.

Claims (15)

1. A method for the desorption of a heater and / or air conditioner arranged in a motor vehicle reac tor ( 12 ) by means of thermal energy, which is supplied to the Sorptionsma material, and an air flow to carry out from the sorption material by the action of heat, characterized in that, taking into account at least two parameters, the required desorption energy (E _Des ) is calculated and, depending on the calculated value, the heat energy (E _w ) contained in the waste heat from drive components ( 40 ) of the motor vehicle (E _wü ) is obtained and fed to the reactor ( 12 ) is and that an _additional electric heater ( 18 , 18 *, 18 **) is operated to cover a residual need (E _el ) of the required desorption energy (E _Des ). 2. The method according to claim 1, characterized in that the thermal energy (E _wü ) from the exhaust gas (A) of an internal combustion engine ( 40 ) is won ge. 3. The method according to claim 1, characterized in that the thermal energy (E _wü ) is obtained from a gaseous or liquid coolant of the internal combustion engine ( 40 ). 4. The method according to claim 2 or 3, characterized in that the thermal energy (E _wü ) in a heat exchanger ( 17 , 32 , 35 ) is transmitted directly to the desorption air flow (DL). 5. The method according to claim 2 or 3, characterized in that the thermal energy (E _wü ) in a heat exchanger ( 36 ) is transferred to an intermediate carrier medium and is guided by the latter into the reactor ( 12 ). 6. The method according to any one of the preceding claims, characterized in that, depending on the value he calculates for the desorption energy (E _Des ), the time (t _{1, 2, 3} ) for switching on the electric additional heater ( 18 , 18 *, 18th **) is determined. 7. The method according to claim 3, characterized in that the heat energy generated by the electrical auxiliary heater (18 *) (E _el ) is transferred to the liquid coolant. 8. The method according to any one of the preceding claims, characterized in that the additional heater ( 18 **) directly heats the sorption material. 9. Heating and / or air conditioning system for a motor vehicle interior with a heater operated by the waste heat of a drive unit ( 8 ) as well as with a sorptive material containing re actuator ( 12 ) for cleaning and / or dehumidifying the motor vehicle interior ( 1 ) Air and means for desorbing the reactor ( 12 ), characterized in that the means for desorbing the reactor ( 12 ) have at least one heat exchanger ( 17 , 17 *, 32 , 35 , 36 , 37 ) for transferring the heat energy contained in the heat on the sorption material and in addition a preferably PTC elements comprising electrical heating device ( 18 , 18 *, 18 **) are provided and with a control device ( 33 ) which is connected to the electrical heating device ( 18 , 18 *, 18 ** ) connected is. 10. Plant according to claim 9, characterized in that the heat exchanger ( 17 , 17 *, 32 ) as a coolant of an internal combustion engine ( 40 ) through which the heat exchanger is formed. 11. Plant according to claim 10, characterized in that the heat exchanger ( 17 ) is arranged together with the electric heating device ( 18 ) in a desorption channel ( 16 ). 12. Plant according to claim 10, characterized in that the heat exchanger ( 32 ) is arranged in a heating device ( 8 ) which by means of an air duct ( 27 ) directly with the vehicle interior ( 1 ) and through an Luftführungska channel ( 28 ) with the reactor ( 12 ) is connected, an air flow control element ( 30 ) being provided for controlling the air flow components through the two air guide channels ( 27 , 28 ). 13. Plant according to claim 9, characterized in that the electrical Heizein direction ( 18 **) within the reactor ( 12 ) is angeord net. 14. Plant according to claim 9 or 13, characterized in that the heat exchanger ( 35 , 36 ) is arranged in an exhaust pipe (exhaust pipe 34 ). 15. Plant according to claim 14, characterized in that the heat exchanger ( 36 ) by means of pipes ( 38 ) connected to the inside the re actuator ( 12 ) arranged heat exchanger ( 37 ) and in the pipe ( 38 ) hen a pump ( 39 ) vorgese is.