GB2120379A

GB2120379A - Heating and ventilating device for the passenger compartment of a motor vehicle

Info

Publication number: GB2120379A
Application number: GB08302782A
Authority: GB
Inventors: Klaus Kossira; Karl Ilzhofer; Dr Gottlieb Wilmers; Wulf Leitermann; Rolf Lechler
Original assignee: Audi NSU Auto Union AG; Audi AG
Current assignee: Audi AG
Priority date: 1982-02-05
Filing date: 1983-02-02
Publication date: 1983-11-30
Also published as: JPS58149817A; GB8302782D0

Abstract

The radiator 4 of a vehicle engine 1 is divided into two sections which can be connected by means of a thermostatic valve 7, of which the one section 4b through which cooling fluid always flows, serves both as a heat exchanger and also as a radiator, and the other section 4a serves merely as a radiator. The radiator 4 is arranged between the engine 1 and the passenger compartment 5, so that an inflow pipe 2 and a return flow pipe 3 are necessary for connecting it to the engine. The section 4b of the radiator which serves as a heat exchanger is here in communication via an air conveyance passage 10 with the passenger compartment 5. An air inflow pipe 11, 13, is provided whereby the air flowing in is not only conveyed via the heat exchanger 4b, and according to the position of guide valves 18, 20 conveyed either into the passenger compartments or into the open air as desired, but also conveyed into the passenger compartment 5 bypassing the heat exchanger 4b. The air flowing through the other section 4a can, if necessary, be conveyed with the air flowing through the heat exchanger 4b, through a further air conveyance passage 8 containing a cooling fan 9, into the open air. <IMAGE>

Description

SPECIFICATION Heating and ventilating device for the passenger compartment of a motor vehicle The invention relates to a heating and ventilating device for the passenger compartments of motor vehicles.

In one known heating and ventilating device the engine radiator is also used for supplying the passenger compartment with heating air. In this design there are provided air conveyance passages via which the air, which flows through the radiator and is heated by it, can be deflected into the open air, or into the passenger compartment. In cold weather there is a delay before the engine and, hence the radiator, becomes hot, hence there is a considerable delay in heating up the passenger compartment, when this heating is most needed. This delay prevents the vehicle being immediately ready to drive when, for example, the window panes are covered with ice, and impairs safety in travel on account of the windows becoming covered with moisture because of the inadequate heating. The comfort of the vehicle users is also impaired.

For this reason, heating and ventilating devices are used which have a separate heat exchanger through which cooling fluid flows. During a cold start at a cool time of year, a thermostatic valve isolates the heat exchanger from the engine cooling fluid which is in the radiator, and thus, because of the reduced quantity of cooling fluid in the heat exchanger, it can be relatively rapidly heated up together with the engine. Hence, heating of the passenger compartment of the vehicle can begin without any prolonged delay.

The provision of an auxiliary heat exchanger does, however, constitute a relatively costly construction which requires a larger space and also introduces an undesirably greater weight on account of the numerous cooling fluid pipes which are necessary. This type of design is therefore not cost-effective. Moreover, this arrangement is usually disposed in front of the engine, or lateraliy of the radiator, and in either position this makes it difficult to achieve a vehicle shape, which is favourable to air flow.

It is an object of the invention to provide a heating and ventilating device, which allows rapid heating of the passenger compartment of a motor vehicle and which is cheaper to make.

From one aspect the invention consists in a heating and ventilating device for the passenger compartment of a motor vehicle which is driven by a fluid-cooled internal combustion engine, having a radiator through which cooling fluid from the engine flows, a cooling fan which cooperates with the latter and a first air conveyance passage, via which the air flowing through the radiator can be conveyed into the open air, and a second air conveyance passage, including, a blower, through which passage fresh air bypassing the radiator and/or air flowing through the radiator, as desired, can be conveyed into the passenger compartment, wherein the radiator has two sections, which are separated from each other and can be connected by means of a thermostatic valve, wherein the first section cooperates with the cooling fan and is connected to the first air conveyance passage leading into the open air and wherein the second section forms a heat exchanger for the heating device, through which exchanger cooling fluid always flows, and which can be connected by a guide valve to the first or second air conveyance passage, as desired.

With the proposed construction, in which the radiator is divided into two sections which can be connected via a thermostatic valve, the radiator with its second section, through which cooling fluid always flows, can be used as a heat exchanger for the heating device at the same time, whilst the first section of the radiator which cooperates with the cooling ventilator and with the section which leads via the air conveyance passage into the open air, serves exclusively for cooling the engine, depending upon requirements.

The structural unit composed of the radiator and the heat exchanger which is provided produces a 'specially compact and simplified assembly and makes possible an arrangement in the motor vehicle which takes up a very small amount of space. The space saved by this means can be utilised for other purposes, for example, for the accommodation of other units. Thus not only is an auxiliary and special heat exchanger unnecessary with this design, but so are the associated cooling fluid pipes, so that not only is a considerable reduction in weight obtained by designing the radiator to be of lightweight construction at the same time, but the assembly expense can also be reduced and therefore the invention provides a cheaper arrangement.

The section of the radiator serving as a heat exchanger can, on the one hand, be very rapidly heated up with the engine in the usual way, because of the separation from the other section of the radiator and the consequent reduction in the quantity of cooling fluid, so that the engine in the warm running phase maches its operating temperature after a short time, and consequently heating of the passenger compartment is very quickly possible. On the other hand, however, the heat exchanger, as a segment of the radiator, contributes together with the first section of the radiator, which is connected via the thermostatic valve, to cooling of the engine which is necessary after the engine operating temperature has been reached.If no heating is desired, the air flowing through the heat exchanger is conveyed through the air conveyance passage leading into the open air, instead of into the passenger compartment.

It has in fact been proposed to divide a radiator into two sections, but the purpose of this design is to prevent the immediate admission of cold cooling water to the engine and the damage caused by this when there is a desultory opening of the thermostatic valve in the cooling circuit. An auxiliary heat exchanger which is connected to the engine is provided for heating the passenger compartment. This arrangement necessitates a relatively large quantity of cooling fluid which has to be heated up by the engine, and consequently leads to a delay in heating up the passenger compartment. There has been no suggestion of the use of at least one part of the radiator for heating purposes.

A common air inflow passages for the first and second section of the radiator can be provided in order to actuate the radiator of the heating and ventilating device according to the invention. It is, however, also possible for an individual air inflow passage to be provided for both the first and second sections of the radiator. The individual air inflow passages are to be preferred if dust is to be prevented from penetrating through the second air conveyance passage into the passenger compartment when, for example, a filter is not in use. The last-mentioned solution is also advantageous if the varying pressure conditions on the outer skin of the motor vehicle are to be used for conveying air into the individual air inflow passages.

In order to be able also to feed fresh air to the passenger compartment if desired, a fresh air passage which bypasses the second section of the radiator is provided, which is connected to an air inflow passage and can be connected to the second air conveyance passage, depending upon the position of a fresh air valve. The fresh air passage can be connected to the air inflow passage, which is coordinated with the second section of the radiator.

This fresh air valve with the guide valve, which connects the second section of the radiator to the first or to the second air conveyance passage, as desired, is assembled in such a way that they are swivelled together, but in opposite directions. The ratio of fresh air to heating air can be sensitively adjusted as a result.

In order to prevent the warm air which is intended for heating the inside of the vehicle being sucked off in an intermediate position of the guide valve, it is advantageous to connect to the second section of the radiator, guide walls which are coordinated with individual areas of this section, and whose ends lie adjacent a cylinder jacket surface at whose centre point a guide valve is rotatably mounted which, in a first limit position; separates the second section from the first air conveyance passage, and in a second limit position, separates it from the second air conveyance passage, and connects areas of the second section of the radiator, which are separated from each other, to the first and second air conveyance passage, by means of the guide valve and one of the guide walls.By this means, the conveyance of cooling air and heating air are separated from each other in every position of the guide valve.

In order to make it possible to rapidly heat the passenger compartment and also the cooling water and therefore the engine, there can be arranged in the air inflow passage of the radiator a known 'per se' valve grid which opens or closes this passage completely or partially, and in addition, an air circulation pipe can be provided, which is in communication with the passenger compartment and opens into the air inflow passage between the valve grid and the radiator, and which can be moved together with the valve grid but in opposite directions. The valve and the closing member can be manually or thermostatically adjustable.

In order to be able to keep the cooling fluid pipes short and also to shape the motor vehicle for favourable air flow over it, the radiator can be arranged between the engine and the passenger compartment, the first air conveyance passage leading into the open air extending downwardly from the radiator and accepting the fan. In order to prevent warm air rising upwards through the first air conveyance passage and being sucked in by the blower during summer running when the guide valve closes the second section of the radiator to the passenger compartment, and the blower merely has to blow fresh air into the passenger compartment, which might occur in the case of a vehicle which is standing in a traffic jam, it is advantageous to provide measures which prevent such a back-flow.If a valve grid is located in the air inflow passage of the cooler to completely or partially open or close this passage, this valve grid can have segments which are parallel and can be swivelled about a horizontal axis in known 'per se' manner, in which case the interspaces between adjacent segments which exist when the valve register is open can be closed by automatically acting return valves. These return valves can be composed of thin-walled indiarubber strips which are pressed into the closed position by the air which rises through the first air conveyance passage. Alternatively, flowback of warm air through the first air conveyance passage can be prevented by the cooling fan automatically rotating at low speed when the first guide valve is closed to the passenger compartment and the fresh air valve is open.

From another aspect the invention consists in a heating and ventilating device for the passenger compartment of a motor vehicle which is driven by a fluid-cooled engine having a radiator through which cooling fluid can be circulated, comprising means for passing fresh air through at least one part of the radiator t6 heat the air, means for selectively venting the heated air or for supplying it to the passenger compartment and valve means for operatively isolating another part of the radiator to reduce the volume of circulating fluid, the arrangement being such that fresh air passing through the one part of the radiator can be rapidly heated when the vehicle is started in cold weather.

The invention may be performed in various ways, specific examples of which wiil now be described with reference to the accompanying drawings, in which: Figure 1 shows a segment of a motor vehicle with a heating and ventilating device according to the invention illustrated diagrammaticaliy; Figure 2 shows a simplified view of a radiator in the direction of the arrow A in Fig. 1; Figure 3 shows a modification of the heating and ventilating device illustrated in Fig. 1; and Figure 4 shows an electrical circuit diagram of the cooling air ventilator.

Figure 1 diagrammatically illustrates the front part of a motor vehicle, which is driven by a fluidcooled engine 1 indicated in dot-dash lines. The engine 1 is connected, via an inflow pipe 2 and a return flow pipe 3, to a radiator 4 through which cooling fluid flows. The circulation of the cooling fluid through the engine 1 and the radiator 4 occurs, with the aid of a pump which is located on the engine 1, in a known 'per se' manner and is not illustrated for this reason. The radiator 4 is arranged between the engine 1 and the passenger compartment 5 - behind the engine 1, viewed in the direction of travel - and is divided into a first section 4a and a second section 4b (see Fig. 2).

The second section 4b of the radiator is connected via the inflow and return flow pipes 2 and 3 to the cooling jacket of the engine 1. The cooling fluid always flows through the second section 4b, which acts as a heat exchanger for the heating device in order to heat up the passenger compartment. The first section 4a can be connected to the second section 4b and the cooling surface increased at the same time by means of a thermostatic valve 7 which - as can be seen in Fig. 2 - is arranged between the section 4a and 4b in a dividing wall 6.

A first air conveyance passage 8 is joined onto the first section 4a of the radiator, which is the bottom one in the drawing, to convey the air flowing through the radiator 4 into the open air. A cooling fan 9 is disposed in the passage 8 to draw fresh air through the radiator 4. The cooling air fan 9 is switched on or off by a thermostatic switch in dependence upon the cooling fluid, e.g.

water, temperature. Adjoining the air conveyance passage 8 at the top is a second air conveyance passage 10, through which fresh air or air flowing through the section 4b, as desired, is conveyed to the passenger compartment 5. Upstream of the radiator 4 there is located an air inflow passage 11 which emanates, for example, from a point above the bonnet 12 and conveys the fresh air, which flows in, to the first section 4a. Fresh air can be conveyed through the second section 4b via a second air inflow passage 13, which emanates from a point between the bonnet 12 and the windscreen 14, and which, upstream of the radiator 4, is joined with a wall 1 9 onto the first air inflow passage 11.Alternatively, the passage 1 3 supplies fresh air via a fresh air passage 15, which bypasses the second section 4b, into the second air conveyance passage 10 and therefore into the passenger compartment 5.

A conventional blower 1 6 is located in the second air conveyance passage 10 in order to increase the current of air.

A fresh air valve 17 is located in the fresh air passage 1 5 and is movable in the direction of the arrow to close or open the fresh air passage 1 5 as desired. Downstream of the radiator 4, a guide valve 1 8 is located in the common wall between the two air conveyance passages 8 and 10 and is movable in the direction of the arrow, so that the air flowing through the second section 4b can be conveyed either into the first air conveyance passage 8 or into the second air conveyance passage 10. The fresh air valve 17 and the guide valve 1 8 are preferably connected together so that they can be operated together, but in opposite directions. The valves can be pivoted by means of a handle which is not illustrated.

In Fig. 2 the radiator is illustrated in a simplified form in the top plan view shown in the direction of the arrow A. As can be seen, the radiator 4 is divided by the partition wall 6 into two sections 4a and 4b, which are, for example, of roughly equal size. The radiator 4 has an input header 2a, which is joined to the inflow pipe 2 and is defined by the partition 6. The input header 2a is connected, via the second section 4b, with an output header 3a, to which the return flow pipe 3 is connected. The header 2a can also be connected via the thermostatic valve 7 to its adjacent header 2b, and thence, via first section 4a, to the header 3a.

When the engine 1 is set in motion in low outside temperatures, the thermostatic valve 7 initially remains closed. The cooling fluid circulating via the inflow pipe 2 and the return pipe 3 is therefore reduced by the quantity which is in the first section 4a, so that a relatively rapid heating of the engine 1 occurs. In addition to the heating of the engine 1, the cooling fluid which passes through the section 4b, which serves as a heat exchanger, is heated up. In the position of the fresh air valve 17 and of the guide valve 18 which is shown in Fig. 1, fresh air enters through the air inflow passage 13, passes through the second section 4b and is heated thereby. The resultant warm air passes through the air conveyance passage 10 into the passenger compartment 3.

The rapid heating-up of the air conveyed via the heat exchanger makes possible not only a rapid heating-up of the passenger compartment but also an equally rapid removal of ice or moisture from the windows when the current is directed in a suitable manner.

With increased heating of the cooling fluid, the thermostatic valve 7 is gradually released, whereby the cooling fluid which is in the first section 4a participates in the cooling of the engine to an increasing extent, and eventually it participates fully when the operating temperature is reached. The heat exchange which occurs between the radiator 4 and the air flowing through it serves in the proposed construction to heat up the passenger compartment on the one hand, and to cool the engine 1 on the other; overheating of the cooling fluid being prevented by the cooling fan 9, which comes into operation in the usual way when the operating temperature is exceeded.

In the event of there being outside temperatures which make heating of the passenger compartment 3 unnecessary, the guide valve 1 8 is brought upwards into the position indicated in dot-dash fashion, so that the heated air flowing through the second section 4b is directed into the air conveyance passage 8 and is expelled by the cooling fan 9, if necessary. At the same time, the fresh air passage 1 5 is opened by appropriate adjustment of the fresh air valve 1 7, whereby fresh air is fed through the air inflow passage 13 to the passenger compartment 3.

Obviously, intermediate positions of the fresh air valve 17 and of the guide valve 1 8 are possible in order to be able to regulate the temperature to that which appears to be suitable for the passenger compartment 3.

The wall 19, which is immediately adjacent to the radiator 4, and lies between the two air inflow passages 11 and 13 can contain a guide valve 20, which is movable in the direction of the arrow, whereby the second section 4b can be supplied with air entering either through the air inflow passage 11 or passage 1 3. This adjustment is particularly advantageous when the different pressure conditions prevailing during travel, at the inlet ports of the air inflow passages 11 and 1 3, result in a greater or lesser flow rate. These different air speeds can be utilized to vary the rate of air flow through section 4b.Similarly, it is possible for the wall 1 9 to run along the line which is marked in dot-dash fashion to show one position of the guide valve 20, so that the radiator 4 is fully supplied by the air which flows in through the air inflow passage 1 The air inflow passage, in contrast to the illustration, can also have its inflow ports on the front of the motor vehicle, that is to say, they can run as indicated in dot-dash fashion at 1 a. The air inflow passage can, however, also be completely dispensed with, within the framework of the invention, so that the air which flows exclusively through the first section 4a of the cooler is taken directly from the engine compartment.Furthermore, the second section 4b of the radiator 4 which is used as a heat exchanger can be made larger or smaller in comparison with the first section 4a, according to the size of the passenger compartment 3 and the engine 1, and also depending upon the quantity of cooling fluid which has to be heated up.

Fig. 3 shows a modification of the heating and ventilating device illustrated in Fig. 1. Here, identical parts have been indicated with the same reference numbers, but with primes. This design differs from that of Fig. 1 initially in that guide walls 21 are connected to the second section 4b' of the radiator 4' which extend over the entire width of the radiator and whose ends lie adjacent a cylinder jacket surface at the centre point 22 of which the guide valve 18' is rotatably mounted.

In intermediate positions of the guide valve 18', i.e.

between the limit position illustrated and the one indicated in dots and dashes, a part of the area of the section 4b' is connected to the first air conveyance passage 8' and the remaining area to the second air conveyance passage 10'; these passages being separated from each other by the cooperation of the guide valve 1 8' with one of the walls 21. As a result, the cooling fan 9' is prevented from sucking-off warm air which is intended for heating the passenger compartment 5'. The radiator 4' is composed of flat ribbed pipes 23 through which cooling water flows, and to which the guide walls 21 are joined and between which the air can flow to the first and/or the second air conveyance passage 8' or 1 0', depending upon the position of the guide valve 18'.

Furthermore, a valve grid 24 is arranged in front of the radiator 4' and the grid has parallel segments 25 which can be pivoted about horizontal axes and which are connected together in a known manner so that they can be pivoted by a lever 26 between a closed and an open position.

An air circulation pipe 28 opens into the space 27 between the valve grid 24 and the radiator 4'. The pipe 28 emanates from the passenger compartment 5' and includes a pivotable closing member 29, which is connected to the lever 26 and can be actuated simultaneously with the valve grid 24, but in opposite directions, by a handle 30 or even by a thermostat, which is not illustrated and which reacts to the temperature in the passenger compartment 5'. When the closing member 29 is closed, the valve grid 24 is open. If rapid heating is desired, the closing member 29 is opened and the valve grid 24 closed, so that the blower 16' substantially sucks-in only circulating air from the passenger compartment 5' and conveys it back again into the passenger compartment.A small quantity of fresh air can also be sucked in through the radiator section 4a' or by intentional imperfect sealing of the valve grid 24, in order to prevent the windows becoming covered with moisture.

The arrangement of the radiator 4 or 4' between the engine and the passenger compartment 5 which is illustrated, makes it possible to have short cooling-fluid pipes and a shape of the front part of the motor vehicle which is favourable to smooth air flow over the vehicle.

On the other hand, it requires that the air conveyance passage 8 or 8' leading into the open air extends downwardly from the radiator. If the vehicle now stands in a traffic jam in the summer and ventilation of the passenger compartment 5 or 5' with cool fresh air is desired, the guide valve 1 8 or 18' is in the position indicated in dot-dash fashion. Warm air may, however, rise upwards through the first air conveyance passage 8 or 8' and pass into the area of the fresh air passage 1 5 or 15' and be sucked-up by the blower 1 6 and 1 6', so that the intended cooling effect is prevented. In order to avoid this, there is located, in the exemplified embodiment illustrated Fig. 3, between each of the adjacent segments 25 of the valve register, an automatically acting return valve 31 in the form of a flexible strip composed, for example, of indiarubber material, which closes the interspace between adjacent valves if a flow should occur from bottom to top; that is from the air conveyance passate 8' to the fresh air passage 15'. Alternatively, and this is also suitable for the design as per Fig. 1, the motor of the cooling fan 9 or 9' can be so connected up that it rotates at low speed when the guide valve 18 or 18' is in the dotdash position, so that a slight partial vacuum is created in the air conveyance passage 8 or 8'. A suitable circuit diagram is illustrated in Fig. 4.

Here, there are located in the circuit of the ventilator motor M, the ignition switch 32 and a thermostatic switch 33, which switches on the motor M in the usual way when a certain cooling water temperature is reached. A resistance 34 is provided in parallel with the thermostatic switch 33 so that it can be connected into the circuit by a switch 35 when the guide valve 1 8 or 18' is in the dot-dash position. When the thermostatic switch 33 is opened, the motor M runs at a reduced speed. A further switch 36 can be located in the shunt. The switch 36 is arranged to be closed only when the vehicle is stationary and is actuated, for example, in dependence upon the rotation of the speedometer shaft. The motor M is thereby prevented from running when the vehicle is travelling, even if the thermostatic valve 33 is open.

In order to prevent an accumulation of heat between the second section 4b' of the radiator 4' and the blower 16' and therefore to prevent overheating of this part of the radiator 4' occurring in the indicated limit positions of the air valve 17' and of the guide valve 1 8' in the event of the blower 1 6' being stationary, the guide valve 18', at least, can be connected to a thermostat which reacts to the temperature in the second section 4b' of the radiator 4'. This is not illustrated in greater detail. By means of this thermostat, the guide valve 18' can be automatically pivoted out of the limit position which is shown, in the direction of the dot-dash limit position, to such an extent that the second section 4b' is ventilated by means of the cooling fan 9'. This causes an accumulation of heat to be broken down and overheating becomes impossible.

Claims

1. A heating and ventilating device for the passenger compartment of a motor vehicle which is driven by a fluid-cooled internal combustion engine, having a radiator through which cooling fluid from the engine flows, a cooling fan which cooperates with the latter and a first air conveyance passage, via which the air flowing through the radiator can be conveyed into the open air, and a second air conveyance passage, including a blower, through which passage fresh air bypassing the radiator and/or flowing through the radiator, as desired, can be conveyed into the passenger compartment, wherein the radiator has two sections, which are separated from each other and can be connected by means of a thermostatic valve, wherein the first section cooperates with the cooling fan and is connected to the first air conveyance passage leading into the open air, and wherein the second section forms a heat exchanger for the heating device, through which exchanger cooling fluid always flows, and which can be connected by a guide valve to the first or second air conveyance passage, as desired.

2. A heating and ventilating device as claimed in Claim 1 further including a common air-inflow passage for the first and second sections of the radiator.

3. A heating and ventilating device as claimed in Claim 1, including a respective individual airinflow passage for the first and second sections of the radiator.

4. A heating and ventilating device as claimed in Claim 2 or Claim 3, further including a fresh air passage, which bypasses the second section of the radiator, and which is connected to an airinflow passage and can be connected to the second air-conveyance passage, depending upon the position of a fresh air valve.

5. A heating and ventilating device as claimed in Claim 4, wherein the guide valve and the fresh air valve are connected together for generally simultaneous operation but in opposite senses.

6. A heating and ventilating device as claimed in Claim 4 as dependent on Claim 3 wherein the fresh air passage is connected to the air-inflow passage, which is associated with the second section of the radiator.

7. A heating and ventilating device as claimed in one or more of the preceding claims, wherein guide walls are attached to the second section of the radiator, the guide walls being associated with individual areas of this section and whose ends lie adjacent a cylinder jacket surface at whose centre point there is rotatably mounted the guide valve which separates the second section from the first air conveyance passage in a first limit position, and from the second-air conveyance passage in a second limit position, and between these limit positions connects the areas of the second section of the radiator, which are separated from each other by the guide valve and a guide wall, to the first and second air conveyance passages.

8. A heating and ventilating device as claimed in one or more of the preceding claims, wherein there is located in the air inflow passage of the radiator a valve grid which completely or partially opens or closes this passage, and wherein an air circulating pipe is provided, which is in communication with the passenger compartment, opens into the air inflow passage between the valve grid and the radiator, and which contains a closing member which can be operated together with the valve grid, but in the opposite sense.

9. A heating and ventilating device as claimed in Claim 8, wherein the valve grid and the closing member can be regulated manually or thermostatically.

10. A heating and ventilating device as claimed in Claim 1 and one of Claims 2 to 9, wherein the radiator is located between the engine and the passenger compartment, and the first air conveyance passage leading into the open air extends downwardly from the radiator and contains the cooling fan.

11. A heating and ventilating device as claimed in Claims 8 and 10, wherein the valve grid has segments which are parallel and can be pivoted together about horizontal axes, and wherein the interspaces which exist between adjacent segments when the valve grid is open can be closed by automatically acting return valves.

12. A heating and ventilating device as claimed in Claim 10, wherein the cooling fan is motor driven and its motor can be switched on at low speed when the guide valve is closed in relation to the second air conveyance passage.

13. A heating and ventilating device for the passenger compartment of a motor vehicle substantially as hereinbefore described with reference to the accompanying drawings.

14. A heating and ventilating device for the passenger compartment of a motor vehicle which is driven by a fluid cooled engine having a radiator through which cooling fluid can be circulated, comprising means for passing fresh air through at least one part of the radiator to heat the air, means for selectively venting the heated air or for supplying it to the passenger compartment and valve means for operatively isolating another part of the radiator to reduce the volume of circulating fluid, the arrangement being such that fresh air passing through the one part of the radiator can be rapidly heated when the vehicle is started in cold weather.

1 5. A heating and ventilating device for the passenger compartment of a motor vehicle which is driven by a fluid-cooled internal combustion engine, having a radiator through which cooling fluid from the engine flows, a cooling fan which cooperates with the latter and a first air conveyance passage, via which the air flowing through the radiator can be conveyed into the open air, and a second air conveyance passage, including a blower, through which passage fresh air bypassing the radiator and/or flowing through the radiator, as desired, can be conveyed into the passenger compartment, wherein the radiator has two sections, which are separated from each other and can be connected by means of a thermostatic valve, wherein the first section cooperates with the cooling fan and is connected to the first air conveyance passage leading into the open air, and wherein the second section forms a heat exchanger for the heating device, through which exchanger cooling fluid always flows, and which can be connected by a guide valve to the first or second air conveyance passage, as desired and wherein guide walls are attached to the second section of the radiator, the guide walls being associated with individual areas of this section and whose ends lie adjacent a cylinder jacket surface at whose centre point there is rotatably mounted the guide valve which separates the second section from the first-air conveyance in a first limit position, and from the second-air conveyance passage in a second limit position, and between these limit positions connects the areas of the second section of the radiator, which are separated from each other by the guide valve and a guide wall, to the first and second air conveyance passages.

1 6. A heating and ventilating device as claimed in Claim 15, wherein there is located in the air inflow passage of the radiator a valve grid which completely or partially opens or closes this passage, and wherein an air circulating pipe is provided, which is in communication with the passenger compartment, opens into the air inflow passage between the valve grid and the radiator, and which contains a closing member which can be operated together with the valve grid, but in the opposite sense.

1 7. A heating and ventilating device as claimed in Claim 1 6 wherein the valve grid and the closing member can be regulated manually or thermostatically.

1 8. A heating and ventilating device as claimed in Claims 16 or 17, wherein the valve grid has segments which are parallel and can be pivoted together about horizontal axes, and wherein the interspaces which exist between adjacent segments when the valve grid is open can be closed by automatically acting return valves.

1 9. A heating and ventilating device as claimed in any one of Claims 1 5 to 1 8 wherein the radiator is located between the engine and the passenger compartment, and the first air conveyance passage leading into the open air extends downwardly from the radiator and contains the cooling fan, which is motor driven, wherein its motor can be switched on at a low speed when the guide valve is closed in relation to the second air conveyance passage.