WO1992012022A1

WO1992012022A1 - Improvements in and relating to automotive vehicles

Info

Publication number: WO1992012022A1
Application number: PCT/SE1992/000007
Authority: WO
Inventors: Sören HÅKANSSON
Original assignee: Uwe-Verken Ab
Priority date: 1991-01-11
Filing date: 1992-01-10
Publication date: 1992-07-23
Also published as: SE468002B; EP0572426A1; SE9100090D0; SE9100090L

Abstract

This invention relates to an improvement in automative vehicles of the kind which include a closed heating/cooling system which carries pressurized liquid and which functions to attemperate the interior spaces of the vehicle. The system includes heat exchanging means, temperature sensing means, liquid conducting lines which are fitted with valves and which direct the circulating medium to a desired vehicle space or desired vehicle spaces. In accordance with the invention, the arrangement includes a function unit (F) which includes at least one inlet port (15) for the liquid flowing from the liquid carrier, and an inlet port and an outlet port (e.g. 16, 17) for each individual climatizing circuit (K1, K2...) and an outlet port (20) which is common to the climatizing circuits (K1, K2) and through which the liquid is returned to the liquid carrier, and a liquid conducting line (21) which permits liquid to flow selectively directly to a return supply line (23) of selectively to one or more branch lines (e.g. 22, 26) such as to deflect inflowing medium to one or more climatizing circuits connected to the branch line or branch lines; and in that the throughflow line is provided with at least two restrictions (24, 25).

Description

Improvements in and Relating to Automotive Vehicles

The present invention relates to an improvement in automotive vehicles of the kind that are provided with a closed, liquid-carrying heating and cooling system which functions to heat and to cool the vehicle interior in a controlled fashion through the medium of radiators and/or blowers.

The term "automotive vehicle", as used here, includes large load-carrying vehicles and/or large passenger vehicles. These vehicles may also be rail-bound vehi¬ cles. The term is also meant to include seagoing vessels and other watercraft.

The term "closed liquid-carrying heating/cooling system" is meant to include both the cooling system of a vehicle equipped with an internal combustion engine and also a separate liquid tank fitted, for instance, to an electrically-driven vehicle, such as a bus or a so- called trolley bus driven by an electric motor. In both of these cases, pressurized fluid is circulated past the various heating/cooling devices included in the system.

The closed heating/cooling system includes heat exchang¬ ing means, temperature sensors, conduits through which circulating pressurized liquid can be selectively di¬ rected so as to pass said liquid through one or more climatizing circuits, or alternatively to cause said liquid to bypass one or more such climatizing circuits, wherein each individual circuit includes a valve means and wherein at least one circuit is optionally fitted with a suction pump. The term "climatizing circuit", as used in this docu¬ ment, indicates that a vehicle can be divided into various spaces or compartments irrespective of its length or of its intended use. For example, a bus intended for city or town traffic may have a first climatizing circuit in the form of a confined driver's space, while the passenger-carrying section of the bus may include one or more individual climatizing circuits. Other types of vehicles can be divided technically into a number of such climatizing circuits, in a correspond¬ ing manner.

The task of installing a climatizing system in a large vehicles, such as a bus or a long-distance lorry or truck, is both a complicated and time-consuming process, which also requires the employment of well-trained and skillful workmen. For instance, the liquid which is circulated under pressure in the system shall normally be delivered to two or more, often mutually separated spaces through a complex conduit system, so as to pro¬ vide acceptable climatic conditions in respective spac¬ es. To this end, each vehicle space is normally provid¬ ed with an indivi-dual climatizing circuit, such that the temperature of respective individual spaces can be controlled through its particular climatizing circuit.

The complexity of such climatizing installations also results in long fault-finding times in the event of a malfunction of the liquid distribution system of the climatizing system, which in turn results in long vehi¬ cle idle times and in high costs for the customer, i.e. the owner of the vehicle. Known systems of this kind include a large number of different components, which experience has shown results in an installation of poorer quality. The large number of soldered joints on the many conduits or pipes included in the system repre¬ sent a latent source of malfunction, among other things.

Manufacture of those climatizing systems which are at present available commercially necessitate the storage of a very large number of different system components.

The traditional climatizing system, particularly stan¬ dard systems installed in buses that are intended for city and town traffic, generate irregular climatizing characteristics or temperature conditions, very much as a result of the traffic conditions under which such vehicles are operated, so-called stop-and-start traffic.

A primary object of the present invention is to provide a system which will supply an optimum amount of energy to each individual climatizing circuit, irrespective of the vehicle driving characteristics.

Another primary object of the present invention is to provide a system which will reduce manufacturing costs, simplify installation of climatizing systems and facili¬ tate the task of finding faults in the system and enable such faults to be remedied quickly, in a surprisingly outstanding fashion. This results in a considerable reduction in costs to the proprietor of the vehicle concerned, in the end term.

The invention is characterized by the features set forth in the characterizing clause of the following Claim 1. By installing, in accordance with the invention, a module-type function unit which is pre-adapted to the requirements of the vehicle concerned and which includes each desired type of distribution means, often for a plurality of climatizing circuits, and by equipping such a function unit with throttle means or restrictions located in particular positions, it is possible to control each individual circuit in a manner which will adjust the interior temperature of the vehicle interior to prevailing requirements. Installation of the func- tion unit also enables the conduits and piping required to be kept short and simple from the aspect of installa¬ tion, which reduces or eliminates possible sources of malfunction in the climatizing system.

Other features of the invention and advantages afforded thereby will be evident from the dependent Claims and also from the drawings and the following description.

The invention will now be described in more detail with reference to a number of exemplifying embodiments there¬ of. In the case of the illustrative embodiments, the vehicle to which the inventive, improved climatizing system is to be installed is assumed to be a bus intend¬ ed for city or town traffic and equipped with an inter- nal combustion engine, where the vehicle cooling system is used to establish a desired temperature in the vehi¬ cle interior to radiation and convection with the aid of conventional radiators and/or blowers incorporated in the system, although such devices form no part of the present invention.

In vehicles of this kind, the parameters or prerequi¬ sites for maintaining desired temperatures constant change with changes in engine speed, giving rise to variations in pressure and fluid flow. The primary object is to provide means which will not jeopardize the function of bringing the different circuits to a desired temperature under all conceivable operating conditions. In the accompanying drawings,

Figure 1 is a perspective view of one embodiment of the function unit forming part of the inventive arrangement; Figure 2 is a block schematic illustrating the function unit of Figure 1, where the broken lines indicate the outer contours of the function unit. In the case of this embodiment, two climatizing circuits are located externally of the function unit, each circuit being intended to attemperate two separate spaces or areas in the vehicle; Figure 3 is a block schematic illustrating a second embodiment of the invention, wherein the vehi- cle concerned is equipped with three climati¬ zing circuits for mutually separate attemper- able spaces in the vehicle; and Figure 4 illustrates a third embodiment of the inven¬ tion which is similar to the Figure 1 embodi- ment but in which certain components of a heat booster unit have been incorporated in the inventive function unit.

Referring first to Figure 2, it will be seen that the illustrated embodiment includes a supply line or pipe 10 which conducts liquid under pressure and^{^}which forms part of a closed circuit for attemperating the interior spaces of a vehicle or a ship. In the contemplated case, namely a vehicle (not shown) fitted with an inter- nal combustion engine, the reference M identifies the engine of the vehicle. As shown schematically in the Figure, the liquid medium conducted by the supply line 10 is taken from the engine cooling system. Since the manner in which the engine and radiator are coordinated and the manner in which thermostats, pressure pumps and other elements coact with the engine and radiator forms no part of the present invention, no description relat¬ ing to these particular components and their particular functions will be described here. The supply line 10 may be optionally connected by means of a line 11 to the infeed side of a known heat booster unit T, the outfeed side of which is provided with a suction pump T and connected to the supply line further upstream in the system. In the contemplated case, the liquid conducted by the supply line 10 can be caused either to pass through the heat booster unit or to bypass said unit, as required. This control of the liquid flow is effected with the aid of valve means (not shown) fitted in the supply line 10.

In the case of the Figure 2 embodiment, the circulating pressurized medium is intended to adjust the vehicle interior to a desired temperature through the medium of a first and a second climatizing circuit Kl and K2 respectively, irrespective of whether the vehicle is driven continuously or if the vehicle stops and starts repeatedly, i.e. a so-called stop-and-start vehicle. Vehicles intended for so-called stop-and-start traffic may have the form of a bus on a regular bus route or a truck or van used to pick up and unload goods locally. In the Figure 2 embodiment, the climatizing circuit Kl may be a defrosting arrangement or the driver's cabin of such a vehicle, while the climatizing circuit K2 may be a circuit for climatizing the load-carrying or passenger-carrying area of the vehicle. This latter area, or space, is provided in a known manner with radiators and/or air blowers and, although not shown in the Figure, is intended to be included as a temperature adjusting part of the climatizing system.

In order to ensure distribution of liquid medium to the various climatizing circuits Kl, K2..., in accordance with the inventive method, the inventive system includes a function element F, whose outer con¬ fines are shown in chain lines in Figures 2-4. The function unit F is shown in perspective in Figure 1 and is comprised, for instance, of a lightmetal block in module form having a main inlet port 15 which is con¬ nected to the supply line 10 for pressurized liquid medium, thus to the high-pressure side of the system, an outlet port 16 through which liquid medium that has been attemperated through the medium of temperature sensing means (not shown) to the first climatizing circuit Kl, and a subsidiary inlet port 17 through which liquid medium that has passed around the circuit Kl while adjusting the temperature of said circuit to a desired level returns to the function unit F. Correspondingly, the function unit F is provided with a port 18 which connects with the inlet side of the second climatizing circuit K2, and a port 19 through which liquid medium is returned to the function unit subsequent to having passed through the circuit K2. Finally, the function unit F of the illustrated first embodiment includes a further port 20 on the low-pressure side of the system, said port being connected to the return supply line designated R in Figures 2-4 discharging into the liquid medium system of the engine M.

As will be made apparent in the following, and particu¬ larly with reference to Figures 2-4, the module-like function unit F is provided with means for distributing the pressurized liquid medium effectively to the various climatizing circuits Kl, K2..., in accordance with the inventive method. As will be seen from Figure 2, the function unit F includes a channel 21 which extends between the liquid medium high-pressure side and the liquid medium low-pressure side. In the case of the

Figure 2 embodiment, the channel 21 which connects the high-pressure side with the low-pressure side is provid¬ ed in the vicinity of the inlet port 15 of the high- pressure side with a branch channel 22 which opens into the port 16 in the function unit F and which is provided with an openable and closeable valve V. The port 16 is connected by means of a connecter (not shown) to the line 22', which is located outside the function unit F and which supplies the first climatizing circuit Kl with pressurized and attemperated liquid medium and the return line 22" of which opens in the port 17 in the function unit F and which forms a part of a liquid medium return channel 23 located within the function unit F. A temperature sensing device which functions to detect the temperature of the circuit Kl is referenced D and is positioned outside the function unit F. It will be understood that the pressure prevailing at the lower branch point PI of the branch line 22 located within the function unit F and in the throughflow channel 21 will normally be higher than the temperature at the branch point or function P0 of the throughflow channel 21 and the return channel 23. In the case of the Figure 2 embodiment, the climatizing circuit Kl is relatively small, and consequently the liquid medium input pressure of the will be sufficient to circulate the liquid medium around the circuit. One proviso in this regard, howev¬ er, is that the port characteristics of the valve V in the line 22 will be suitable for this purpose. This does not exclude, however, the provision of a suction pump in this small circuit. As will be evident from the following description, a restriction 24 provided in the supply line 21 is highly significant to the optimum functioning of the climatizing circuits Kl, K2.

As shown in Figure 2, the channel 21 in the function unit F is provided with a first restriction 24 upstream of the branch point or function Pi, and is provided with a second restriction 25 upstream of the first restric¬ tion 24. These two restrictions may have the form of valves or may be factual restrictions with fixed throughflow areas. Connected to that section of the line 21 which extends between the restrictions 24, 25 is a branch line 26 where the pressure prevailing at the branch point or function Ps is normally lower than the pressure prevailing at the branch point or function Pi, but higher than the pressure prevailing at Po. These two restrictions 24, 25 and their throughflow character¬ istics are highly essential to the efficient operation of the system and are have an optimum function irrespec¬ tive of vehicle driving conditions, i.e. in the present case, irrespective of the speed of the engine M.

The branch line 26 located in the function unit F and supplied with liquid medium from the line 21 is provided with an openable the closeable valve 27 and is connected to one end of a suction pump 28 which belongs to the second climatizing circuit K2 and which may optionally be integrated with the function unit F, the port 18 of which is connected to the line 26' by means of a con¬ necting piece (not shown), the return side 26" of said line 26' discharging into the port 19 in the function unit F. According to the invention, the function unit F includes an elongated channel 29 which communicates with the second climatizing circuit K2, said channel 29 extending parallel with the line 21 and providing liquid communication between the two different pressure sides of the circuit K2. A pressure Ps prevails in the chan¬ nel 29 at the branch point of the channel 26 and the channel 29, while a normally lower pressure Po prevails at the junction point of the return line 26" and the channel 29 when the valve 27 is open. The valve 27 is opened and closed by means of a tempera¬ ture sensing device, symbolically referenced D, provided on the line 26'. When the liquid medium in the circuit K2 has reached a predetermined temperature, the tempera- ture sensing device D sends a signal to the valve 27 on the line 26, causing the valve to close. The liquid medium in the circuit K2 will therewith travel through the line 26', 26" and via the branch point or junction Po between the line 26'and the line 29, back through the line 29 under the influence of the suction pump 28. When the temperature sensing device detects that the temperature of the liquid medium in the line 26' devi¬ ates from said predetermined value, the sensor sends a commensurate signal to the valve 27, causing the valve to open and allow attemperated liquid medium to flow into the circuit K2 from the throughflow line 21 and the supply line 26. When the valve 27 is open, liquid medium will pass around the circuit K2 and flow back to the engine cooling system via the line 29' and the return line R. Located between the branch points Ps and Po in the line 29 is a restriction 30 which in conjunc¬ tion with the lower pressure prevailing at Po enables this return of liquid medium to take place. The line 29' also functions as an air ventilating line for purg- ing the system of any air that may be present.

It will be obvious from the aforegoing, to one of normal skill in this art, that the presence of the restriction 24 in the throughflow line 21 ensures optimum delivery of liquid medium to the circuit Kl (which is not a closed circuit). Furthermore, when the valve 27 on the line 26 to the circuit K2 is open, the pressure that prevails at the branch point Ps on the line 21 will be lower than the pressure that prevails at the point Po, which assists in maintaining sufficient flow of liquid medium through the circuit Kl when the vehicle engine is running at low speed.

In the case of the climatizing circuit K2, the pump 28 and the line 29 are intended ensure that the liquid medium is delivered to said circuit in an amount suffi¬ cient to ensure that the vehicle interior and the space served by the climatizing circuit K2 will be brought to the desired temperature, irrespective of the vehicle engine speed.

The embodiment illustrated in Figure 3 includes a third vehicle climatizing circuit K3. Liquid medium is deliv¬ ered to this circuit from a branch line 31 which is located on the line 26 upstream of the valve 27 of the circuit K2. The branch line 31 is fitted with a valve 32 which is opened and closed by means of the tempera¬ ture sensing device D located on the pressure side of the suction pump 33. Liquid medium is delivered to the climatizing circuit K3 via the line 31'. Similar to the climatizing circuit K2, liquid medium is returned to the circuit K3 through a line 34 connected to the return line 23. When the valve 32 serving the circuit K3 has closed, this will indicate that the temperature of the liquid medium in the circuit K3 is the desired tempera¬ ture. When the circuit K3 is a closed circuit, i.e. when liquid medium that has flowed through the circuit K3 and has reached the branch point Po, the pressure at Po will be so low that the pump 33 will cause the liquid medium to return to the circuit K3, via the restriction 35. Although the drawing shows^"otherwise, it is pre¬ ferred that the suction pump 33 is integrated with the function unit F.

Finally, in Figure 4, there is shown a further embodi¬ ment of the invention, which can be said to be a modified version of the Figure 2 embodiment. In the case of the Figure 4 embodiment, the function unit F is enlarged to include a line part 40 whose one end is connected to the liquid medium supply line 10 and whose other end is connected to the throughflow line 21 in the function unit F. Located between the two ends of the line part 40 in the function unit F is a branch line 42 which leads to the input side of a heat booster T, via a port 43 and a line 44 which extends outside the function unit F. The output side of the heat booster is connect¬ ed to the line part 40 via a line 45, a port 46 in the function unit F and a short line 47. A non-return valve

48 is integrated with the function unit F between the points of connection of respective lines 42 and 47 with the line part 40. When the heat booster T is not in use, the non-return valve 48 is open and allows liquid medium to flow directly to the throughflow line 21, via the supply line 10. When the heat booster T is in use, the non-return valve 48 is closed and the flow of liquid medium is directed through the heat booster T. A filter

49 may be built into the line part 40 for the purpose of cleaning the liquid medium system as a whole from solid impurities.

This arrangement will ensure a reliable flow of liquid medium when the heat booster is in use, a circumstance which often occurs in regular bus traffic.

Integration of the components 40, 42, 43, 46, 47, 48 and 49 in the function unit F also ensures the possibility of rendering both installation and fitting of a heat booster more effective.

Each of the three illustrated and described embodiments includes other, known elements (not shown) , such as a heat exchanger for instance. It will be evident from the aforegoing that the valve included in each circuit Kl, K2, K3 and integrated with the function unit F is controlled by temperature sensing devices connected in respective circuits. When the valve of any one of the circuits Kl, K2, K3 is closed, the liquid medium is directed to one or the other of the open circuits. If the valve of each circuit Kl, K2, K3 is closed, the liquid medium is directed immediately to the return flow line 23 in the function unit F on the low-pressure side of the system, via the throughflow channel 21.

When the function unit F is constructed in accordance with the Figure 3 embodiment, corresponding liquid-flow inlet and liquid-flow outlet ports are, of course, provided said inlet and outlet being referenced 50 and 51 respectively in Figure 1.

The valves, for instance valves 27, 32, used in respec¬ tive climatizing circuits may be solenoid-operated compressed-air valves. Naturally, other types of valves may be used.

Although the described and illustrated embodiments are intended for installation in a vehicle which is fitted with an internal combustion engine, it will be under¬ stood that the liquid circulated from the engine cooling system and here referred to as liquid medium may have any desired composition and can be forced from a liquid tank installed, for instance, in an electrically-driven bus, a rail-bound vehicle or a ship. The Figure 4 embodiment is preferred when the vehicle concerned is a bus and where the presence of a heat booster is often required. No values relating to the throughflow areas of the lines located within the function unit F have been given in the aforegoing, since these areas are dependent on the pressure of the circulating liquid. A typical pressure in the lines installed in a vehicle driven by an internal combustion engine is 0.5 bar. It is conceivable that the requisite pressure will be higher than this typical pressure, in which case the throughflow areas must be changed accordingly.

The pressure drop Pi-Po shall be greater than the pres¬ sure drop across the vehicle radiator so as not to jeopardize driving of the vehicle in the summer months. The pressure drop across Pi-Po, however, shall not be so great as to activate the heat booster, when fitted, as a result of overheating when none of the circuits calls for heat.

The circuit K2, for instance, is normally provided with liquid from the primary side. Should the call for liquid be so great as to prevent this from taking place, requisite additional liquid can be supplied to the circuit K2 via Po on the return line 23 through the restriction 25, i.e. through the back door to said circuit, in a manner of speaking.

It will be understood from the aforegoing that the component referred to in the drawings as an engine can equally as well be a tank which contains an appropriate liquid medium. In both cases, pressurized liquid is delivered from one side of said component and returned to the other side thereof, so as to create a circulation system. As before mentioned, the system may include heat exchange devices, among other things.

Claims

1. An improvement in automotive vehicles of the kind provided with a closed heating/cooling system in which a pressurized liquid medium is circulated for the purpose of controlled heating and cooling (attemperation) of the vehicle interior, said system comprising heat exchanging means, temperature sensing means, liquid conducting lines provided with valves and functioning to direct the circulating medium selectively in a manner to cause said medium to pass through and attemperate a particular space or particular spaces (climatizing circuits) in the vehicle, each of said circuits including an openable and closeable valve means and of which circuits at least one is provided with a suction pump, c h a r a c ¬ t e r i z e d by a function unit (F) which includes at least one inlet port (15) for the liquid flowing from the liquid carrier, and an inlet port and an outlet port (e.g. 16, 17) for each individual climatizing circuit (Kl, K2...) and an outlet port (20) which is common to the climatizing circuits (Kl, K2) and through which said liquid is returned to said liquid carrier, and a liquid conducting line (21) which permits liquid to flow selec- tively directly to a return supply line (23) or_selec¬ tively to one or more branch lines (e.g. 22, 26) such as to deflect inflowing medium to one or more climatizing circuits connected to the branch line or branch lines; and in that said throughflow line is provided with at least two restrictions (24, 25).

2. An improvement according to Claim 1, c h a r a c ¬ t e r i z e d in that the function unit (F) also includes for each individual climatizing circuit (Kl, K2...) a respective openable and closeable valve means (V, 27, 32), whose operation state is dependent on circuit temperature sensing means (D, D3), preferably located outside the function unit.

3. An improvement according to Claim 1, c h a r a c - t e r i z e d in that the throughflow line (21) of the function unit (F) communicates at points along its length with preferably two mutually-spaced branch lines (22, 26) each communicating with a separate climatizing circuit (Kl, K2); and in that the throughflow line (21) is provided with a first restriction (24) at a location between said branch points (Pi, Ps) and with a second restriction (25) at a location upstream of that branch point which is distal from the liquid inlet end (15).

4. An improvement according to one or more of the preceding Claims, c h a r a c t e r i z e d in that the pressurized-liquid supply line (10) coacts with a heat booster (T) in a known manner.

5. An arrangement according to one or more of the preceding Claims, c h a r a c t e r i z e d in that at least one of the climatizing circuits (K2, K3) forms a closed circulation system which is dependent on the Tiiohϊtσred delivery of thermal energy to the system.

6. An arrangement according to Claim 5, c h a r a c ¬ t e r i z e d in that the function unit (F) includes a further liquid conducting line (29, 34') which enables liquid to flow from the outlet side of a- climatizing circuit back to the supply side of said circuit in accordance with the detected temperature of the flowing liquid.

7. An arrangement according to one or more of the preceding Claims, c h a r a c t e r i z e d in that the throughflow channel (21) in the function unit (F) includes two branch lines (22, 26) which are located within said function unit and each of which coacts with a particular climatizing circuit (Kl, K2); and in that each further climatizing circuit (K3) is supplied with liquid from one of the upstream branch lines (22 or 26) via a branch (31).

8. An arrangement according to one or more of the preceding Claims, c h a r a c t e r i z e d in that the pump (28, 33) assigned to each climatizing circuit is located within the function unit (F).

9. An arrangement according to one or more of the preceding Claims, c h a r a c t e r i z e d in that each of the climatizing circuits (K2, K3) includes a restriction (30, 35) in the line extension between the outlet side of the circuit (K2, K3) and its inlet side.

10. An arrangement according to one or more of the preceding Claims, in which a heat booster (T) is mounted externally of the function unit, c h a r a c ¬ t e r i z e d in that the function unit (F) includes between the throughflow line (21) and the inlet (15) to the supply line (10) a line part (40) which has a non- return valve (48) fitted somewhere along its length; in that liquid conducting lines (42, 47) communicate mutu¬ ally on both sides of the non-return valve (48); and in that each of the last mentioned lines communicates with the inlet and outlet side of the heat booster (T) res- pectively via ports (43, 46) in the function unit (F) .