Means and method for heating and colling a utility space of a motor vehicle

The invention relates to a device for heating and Cooling a useful space after the in the preamble Claim 1 near defined type and a method for operating the device according to the preamble of claim 11 further defined type.

From DE 33 18 025 A1, a device of the initially mentioned type for motor vehicles with an evaporator known that the exhaust gases from an internal combustion engine is heated. The evaporator is a Expansion valve in series, which while effective only is, to the waste heat from the internal combustion engine a predetermined has value. Moreover, in this Air conditioning arranged a compressor with the Change the effective cross section of the expansion valve a speed reduction to a non-zero experiencing different value. The heating takes place located in this air conditioner in three stages. In the first stage, shortly after the start of the motor vehicle, compresses the refrigerant compressor and supplies it to a four-way valve to the evaporator to where a heat exchange from the refrigerant to the Usable space inflowing Nutzraumluft is transmitted. is with a sufficient waste heat from the internal combustion engine a bypass line including an exhaust gas heat exchanger, switched by switching a three-way valve. This delivers the waste heat from the internal combustion engine required for heating the interior of Warmth. Following this, the usual heating operation with the aid of an air-refrigerant heat exchanger, the fed with the coolant of the internal combustion engine becomes. In this third stage is the bypass line switched off again. Initially, the expansion valve closed and in the bypass line located refrigerant evacuated with the help of the compressor.

A disadvantage of this known solution is, however, tHe the three-stage heating of air conditioning a high constructive and control engineering effort requires.

Furthermore, from DE 34 43 899 C2 a device for heating and cooling a useful space of a a Internal combustion engine driven vehicle known. In this known device, when the Nutzraumluft to be heated, the refrigerant after the compressor via a refrigerant in a crossover to of containing the condenser and the expansion device parallel bypass line out. In this by-pass line in a heat exchanger by an intermediate closed air circuit the Refrigerant heated by the intermediate air. In the heat exchanger Between the air circuit is the there means of a blower required between air through the exhaust stream of the engine warmed.

The disadvantage here is that described in addition to the complexity Solution that an auxiliary mass flow of heat transfer has to be heated, and only a subset of the heat usable transfers. Further, low in efficiency-optimized motors heat in the exhaust gas by the unavoidable transfer losses and further reduced due to the thermal Mass of the components additionally involved only transfer delays.

The present invention is therefore an object based on the on the refrigerant circuit on Nutzraumluft heat transmitted power for vehicles, particularly in fuel-efficient vehicles as For example, diesel vehicles, total and immediate to increase after commissioning, the effectiveness a device for heating and cooling to increase and decrease their response time.

According to the invention this object is achieved by the characterizing said part of the apparatus claim 1 Characteristics as well as the in the characterizing part of the Method claim process steps mentioned 11 dissolved.

In use of the apparatus for heating a The useful space of a motor vehicle, the refrigerant in an advantageous manner in succession in the expander to a temperature below a suction temperature the refrigerant is expanded in the compressor, in the ambient heat exchanger with ambient air acted upon, in the exhaust gas heat exchanger with Exhaust gases of the internal combustion engine is heated, in the compressor compressed in the indoor heat exchanger pressurized cold air and the interior of the vehicle Vehicle interior with the indoor heat exchanger heated car interior air heated.

Through the inventive serial arrangement of components allowing a thermodynamic cycle process, in which heating and cooling capacity under nearly all operating states of the internal combustion engine to a sufficient Measurements can be made available. Here, the refrigerant mass flow through the compressor is depending on the required heating or Cooling capacity is regulated such that the interior heat exchanger of the absorbed or dissipated Power required refrigerant mass flow available stands.

The refrigerant mass flow is largely independent from the process pressure in the circuit, so that the device, even with little or large power requirement, constantly operated in a region with a high efficiency can be. This is a control range of heating or Cooling capacity from 0 to a maximum, in technically feasible fully attainable value with a high efficiency of the device obtained.

The inventive process is the mass flow the refrigerant depending demanded by the Heating power and the amount of heat offered around and the waste heat from the internal combustion engine as required varies so that in a simple manner for the Cooling in summer fixed air conditioning Heating the interior of the motor vehicle on cold is days available.

Advantageous developments and refinements of The invention result from the dependent claims and from the described below in principle with reference to the drawing Embodiments.

It shows:<dl tsize="7" compact="compact"><dt>Fig. 1</dt><dd>a circuit diagram of a device for heating and cooling a useful space of a motor vehicle,</dd><dt>FIG. 2</dt><dd>a schematic diagram of another embodiment the device for heating and cooling a useful space of a motor vehicle in accordance with Fig. 1;</dd><dt>Fig. 3</dt><dd>a schematic diagram of another embodiment the device for heating and cooling a useful space of a motor vehicle in accordance with Fig. 1 and Fig. 2; </dd><dt>Fig. 4</dt><dd>a refrigerant line, the spirally to an exhaust pipe is arranged;</dd><dt>Fig. 5</dt><dd>an exhaust heat exchanger with a control device, as a sheathing Tube is shown;</dd><dt>Fig. 6</dt><dd>an embodiment of an expansion device, the two parallel coolant lines each having an expansion valve and a check valve included;</dd><dt>Fig. 7</dt><dd>an embodiment of the expansion means according to FIG. 6, the two parallel coolant lines Having in each case a Expansion valve and a check valve, which are represented as spatial entity, contain; and</dd><dt>Fig. 8</dt><dd>an embodiment of the expansion means FIG. 6 and FIG. 7, the refrigerant line a having that as a spatially trained unit trained combined Expansion valve contains.</dd></dl>

In Fig. 1 is a schematic diagram of an apparatus for Heating and cooling a useful space of a motor vehicle presented with an internal combustion engine 1, wherein the solid arrows indicate the flow direction of a Refrigerant for heating and the dashed executed Arrows the flow direction for cooling mode Show.

The refrigerant during the heating operation of a Compressor 2 is compressed and passes into a refrigerant line 3 to a 3/2 way valve 4, which as formed mode switch for heating or cooling mode is. In heating mode, the refrigerant is a Line 5 led to an indoor heat exchanger 6, where it with colder Nutzraumluft which through the indoor heat exchanger 6 flows into the chamber, the pressurized becomes. The refrigerant flows from the indoor heat exchanger 6 to a refrigerant pipe 7 an expansion device 8. From there flows the Refrigerant through a pipe 9 to an ambient heat exchanger 10 and is acted upon with ambient air. In the ambient heat exchanger 10, the Refrigerant heated and flows by the ambient air then via a refrigerant line 11 and a 3/2 way valve 12 to an exhaust gas heat exchanger. 13 There, the refrigerant with the hot exhaust gases is the Internal combustion engine 1 and urged further heated. From the exhaust gas heat exchanger 13 enters the refrigerant a 3/2 way valve 14, which as a circulation valve is formed, and a refrigerant line 15 back to the compressor 2, whereby the cycle is closed is.

If the refrigerant in the expansion device 8 expanding to a temperature below the ambient temperature lies, the ambient heat exchanger 10 ambient air flowing through to a temperature cooled below its saturation temperature will. In this case, the water condenses, with which the ambient air is loaded, the ambient heat exchanger 10 out. If the temperature of the Refrigerant below the sublimation of the water, this goes over to the solid state, ie comes to icing of the heat exchanger around 10. In order to avoid this phenomenon, it is about 3/2 Way valve 12 opens a bypass line 16 and the Line 11 closed, so that the ambient heat exchanger 10 is no longer flowing through the refrigerant becomes.

In FIG. 2 is a schematic diagram of another embodiment the device for heating and cooling a The useful space of a motor vehicle according to FIGS. 1. In this embodiment flows the compressed The refrigerant of the compressor 2 through a 4/2 way valve 17, by means of which the relevant for the Mode heating or cooling required Flow path of the refrigerant is adjusted.

The solid arrows represent the direction of flow the refrigerant for heating and the dashed Arrows the direction of flow for the cooling operation represent.

During heating, the refrigerant flows first by dissipating heat through the indoor heat exchanger 6, but will be in the expansion unit 8 to a temperature below the ambient temperature Temperature expands and then successively in the ambient heat exchanger 10 and the exhaust gas heat exchanger 13 heats. From there it flows through a Check valve 18 into the intake of the compressor . 2

To a check valve 19 is due to pressure loss in the circuit components on its blocking Page no lower pressure than at its Durchflußseite and thus remains as a result of Closing action of a not shown element, which may be designed as a spring, closed. allows a 3/2 way valve circuit 20 in its rest position described above Circulation of the refrigerant.

If the 3/2 way circulation valve 20 is switched, so the refrigerant before the ambient heat exchanger 10 directly into the exhaust gas heat exchanger 13 and from the compressor 2 is sucked.

Also in this case the pressure difference is at the check valve 19 sufficient to flow through ensure the exhaust gas heat exchanger. 13

During cooling operation, the refrigerant flows after the compression on the left in the rest position 4/2 way valve 17 and the check valve 19 in the Ambient heat exchanger 10 and is there with cooler Ambient air is applied. Thereafter, the refrigerant flows through the expansion device 8, is there expanded and the indoor heat exchanger 6 with warmer, the useful space supplied Nutzraumluft applied. The heated refrigerant then flows to the Compressor 2 and is compressed there again, which the refrigerant circuit is closed.

An illegal connection of the refrigerant circuit via the check valve 18 is avoided, that the pressure on the basis of the Durchflußseite Pressure loss is lower than on the barrier Page.

In Fig. 3 is a schematic diagram of another embodiment the device for heating and cooling a The useful space of a motor vehicle according to FIG. 1 and Fig. 2 shown. A valve 21 opens in switching position a bypass line 22 to the exhaust gas heat exchanger 13. Because of the pressure loss of refrigerant in the ambient heat exchanger 10 is only a small fraction to flow through them so that the majority of the refrigerant directly from the expansion device 8 reaches the exhaust gas heat exchanger 13 without on days with high humidity and / or low temperatures the refrigerant cools or heat absorbing to a low pressure which is an inefficient Compressor power input are effected, expanded have to be.

In a buffer tank 23 is depending on the operating mode Heating or cooling due to its storage capacity of refrigerant the refrigerant charge of the different Volumes of the high-pressure side and low-pressure side and depending on the temperatures at Heat and evaporation an adequate intake ensures the compressor. 2 simultaneously he collects excess amounts of refrigerant from the Circulation at low cooling capacity required, eg for low pressures on the high pressure side. Furthermore is in the buffer tank 23 for accommodating an adsorbent provided by befindlichem in the circulating water.

In FIG. 4, the exhaust gas heat exchanger 13 is illustrated. In the structural design of the exhaust heat exchanger 13 is a coolant conduit 24 helically disposed on the outside of an exhaust pipe 25th Advantageously, the exhaust gas heat exchanger is 13 as formed counterflow heat exchanger, wherein the flow direction the refrigerant by an arrow the label A at the inlet of the exhaust gas heat exchanger 13 and by an arrow with the label B at the outlet is marked. The direction of flow Exhaust gas of the internal combustion engine 1, which in counter-current is supplied to the refrigerant is by a Arrow C at the inlet of the heat exchanging area the exhaust pipe 25 and at the outlet by the Arrow labeled as D. The advantage, that the exhaust gases and the refrigerant in counter-current are guided to one another is that between two media throughout the heat transfer always present the maximum temperature difference and thus a good degree of exchange of the exhaust heat exchanger is achieved thirteenth

The spiral refrigerant pipes 24 of the exhaust gas heat exchanger 13 are in the range a in the exhaust line 25 arranged exhaust gas cleaning system, the not shown in more detail in the drawing, or located downstream of this to the conversion not to interfere with the exhaust gases.

In FIG. 5, the exhaust gas heat exchanger 13 is shown, the additional control device 26 for the to transferring heat from the exhaust gases to the refrigerant having. The control device 26 is by an exhaust pipe 25 sheathing tube 27 is formed, the one inlet opening 28 for a wind and said in her in the flow direction wide cross-section is so closed, that it at its outlet 29 with a back pressure of is acted slipstream. In this way, the transferable amount of heat from the exhaust gas to the refrigerant regulated. Thus the possibility exists shortly after Start-up of the motor vehicle, wherein the exhaust gases lower compared to the steady-state operation have temperature, the outlet 29 of the control device 26 to close and thus a cooling of the refrigerant in the refrigerant line 24 through overflowing colder ambient air to avoid. on the other hand , the outlet 29 in the stationary operating state be opened such that the through the inlet opening 28 ambient air flowing flows away via the refrigerant line 24, and thus Heat through the outlet 29 discharges.

In Fig. 6 is an exemplary example of the structure the expansion means 8 shown. Here are two parallel refrigerant lines 30 and 31 shown, each of a series connected Expansion valve 32 or 33 and a check valve 34 and 35 contain. During the heating operation is in the refrigerant pipe 30, the refrigerant in the expansion valve 32 expanded and then flows through the Check valve 34. The refrigerant line 31 however, is by the action of the check valve 35 for the refrigerant not passable and thus acts as a blocking device. In cooling mode, in FIG. 1 is represented by the dashed arrows, on the other hand affects the refrigerant line 30 to the expansion valve 32 and the check valve 34 as Locking device and is in the refrigerant line 31 the refrigerant expanded by the expansion valve 33rd

FIG. 7 shows as a variant in Fig. 6 shown parallel refrigerant lines 30 and 31, the expansion valve 32 and 33, and the check valve 34 or 35 as a spatial unit. This thus combined Expansion and non-return valves 36 and 37 assume the same functions as those described above, in their design spatially separate expansion valves 32 and 33 and check valves 34 or 35 as an expansion device 8 according to the schematic diagram in FIG. 1.

In FIG. 8, the expansion means 8 only the refrigerant pipes 38 and 39 which in a a structural unit executed combined expansion valve 40 included that in the heating mode Flow direction of the refrigerant, the refrigerant expanding and cooling operation, also the refrigerant expands in the flow direction.

By means of a method for heating and cooling a Useful space driven by an internal combustion engine 1 Motor vehicle, the refrigerant in the heating mode one after another in the expansion device 8 a temperature below the suction temperature of the Refrigerant of the compressor 2 is expanded in the ambient heat exchanger 10 with warmer ambient air acted upon, in the exhaust heat exchanger 13 with the Exhaust gases of the internal combustion engine 1 is heated in the compressor 2 compressed in the indoor heat exchanger 6 cooled with cold air, and thus the vehicle interior the vehicle interior warmed up.

In cooling mode, the refrigerant is successively in the ambient heat exchanger 10 with colder ambient air and acted upon in the expander 8 to a temperature below a Nutzraumlufttemperatur expanded, wherein the Nutzraumluft in the indoor heat exchanger 6 charged with the colder refrigerant becomes.

A particularly suitable refrigerant has carbon dioxide (CO₂) Proved that environmentally sound, not is flammable and non-toxic. Moreover, CO₂ a high volumetric cooling capacity, which in Compared with other refrigerants lower circulating mass flow in the heating device requires cooling and the same performance.