| DE1576700A1 | 1970-07-16 | |||
| DE3206239A1 | 1983-09-01 | |||
| FR2443346A1 | 1980-07-04 |
| 1. | A cooling system for internal combustion engine vehicles using liquid as a coolant, said system compris ing a radiator (20) which is connected to the engine cooling circuit, and a heating arrangement (22) which is connected to the heating circuit of the vehicle inter¬ ior, and in which system a liquidfilled heatinsulated container (23) is connected in the interior heating circuit between the engine and the heating arrangement so as to maintain the temperature of the coolant when the engine is switched off, c h a r a c t e r i z e d in that the interior heating circuit is drawn through the insulated container (23) in the form of a heating spiral (14); and in that the spiral wall is thinned at its point of entry into the container and also at its point of exit from the container (23), these thinned portions forming barriers or chokes which prevent heat leaking from the container through the spiral. |
| 2. | A cooling system according to Claim 1, c h r ¬ a c t e r i z e d in that the container input portion and the container output portion of the spiral (14) are located at the lowermost part of the spiral, so as to prevent hea being lost from the container through self circulation in the spiral when the engine is switched off. |
| 3. | A cooling system according to Claim 1 or 2, c h a r a c t e r i z e d by a heat source (11) , such as an electric resistance wire to which current is supplied from the vehicle battery, said heat source (11) being mounted within the heatinsulated container (23). |
| 4. | A cooling system according to any one of Claims 13, c h a r a c t e r i z e d in that a loop (15, 16, 18) is drawn through the heatinsulated container from the vehicle container which contains liquid for cleaning the windscreen and headlamp glasses of the vehicle. |
The present invention relates to a cooling system for vehicles driven by internal combustion engines cooled by a liquid coolant. The system includes a radiator or cooler which is connected to the engine cooling circuit and a heating arrangement which is connected to the vehicle interior heating circuit, and further includes a heat-insulated container which is connected between the engine and the heat arrangement and which functions to maintain the temperature of the coolant when the engine is switched off.
A cooling system which includes a liquid container for maintaining the temperature of the coolant when the engine is switched off is known, for instance, from published French Patent Application 2,443,346.
An object of the present invention is to provide liquid cooled vehicles that are driven by an internal combus¬ tion engine with a heat-insulated container in which the heat content of the liquid coolant is maintained to the greatest possible extent after switching off the engine, so that this heat content can be used for heating the vehicle interior when the engine is next started.
This object is achieved with an inventive cooling system having the characteristic features set forth in the following Claims.
The inventive cooling system functions to heat the vehicle interior quickly to a normal or typical tempera¬ ture when the engine is started, so as to avoid fogging of the inner surfaces of the vehicle windows as a result of the rapidly rising temperature of the vehicle interior.
The invention will now be described in more detail with reference to exemplifying embodiments thereof and also with reference to the accompanying drawings, in which Figure 1 is a principle illustration of a first embodi- ment of the invention; Figure 2 illustrates a second embodiment of the invention, showing the heat-insulated container; Figure 3 illustrates a conventional cooling and interior heating circuit installed in a vehicle driven by an internal combustion engine; Figure 4 illus- trates the circuit shown in Figure 3 with an inventive heat-insulated container connected to said circuit; Figure 5 is a diagram which illustrates the container temperature; Figure 6 is a diagram illustrating time- dependent engine temperature after starting the engine and at different container conditions; Figure 7 is a sectioned view of the heat-insulated container provided with a cooling liquid coil; Figure 8 is an end-view of the coil fitted to the container illustrated in Figure 7; Figure 9 is a sectional view showing part of a wall in the container shown in Figure 7 on a larger scale; and Figure 10 illustrates in larger scale part of the coil shown in Figure 8.
The heat-insulated container 23 shown in Figure 1 has an insulated outer casing 10 provided with a coolant inlet 12 and a coolant outlet 13. A heating source 11, which may be connected to the batteries of the vehicle for instance, assists in maintaining the temperature of the liquid coolant in the container 23 and is controlled by a thermostat T. In the case of the container illustrated in Figure 2, the liquid coolant circulates in a separate coil or loop 14 and therewith delivers heat to the liquid in the container 23 and maintains the temperature of said liquid with the aid of a heating source 11 whose function is controlled by a thermostat T , as illustrat¬ ed in Figure 1. A further coil or loop 15, 16, 18 is
drawn through the container 10 and functions to heat liquid in the container for washing the vehicle wind¬ screen and also the vehicle headlamps. Figure 3 illus¬ trates the principle of a conventional cooling and vehicle-interior heating system installed in a vehicle driven by an internal combustion engine. The conduit or line extending from the engine 21 to the radiator 20 is provided with a thermostat T, in a conventional manner. The vehicle-interior heating circuit includes an engine inlet 211 and an engine outlet 212 and a heating-ar¬ rangement inlet 221 and a heating-arrangement outlet 222. In the case of the embodiment illustrated in Figure 4, which is the preferred inventive embodiment, a heat- insulating container 23 according to Figures 1 and 2 is connected between the engine 21 and the heating arrange¬ ment 22.
The diagram shown in Figure 5 illustrates how the tem¬ perature in the heat-insulating container 23 falls with time. The curve 4 in Figure 5 illustrates the tempera¬ ture drop in the container 23 when no additional heat is supplied to said container from the heat source 11 and when the ambient temperature is -8°C. In the case of the temperature shown by curve 1, the additional power delivered to the container 23 from the heating source 11 is 21 Watts and the ambient temperature is -3°C. In the case of curve 2, the additional heat delivered to the container 23 from the heating source 11 is 21 Watts and the outer temperature is -8°C. Finally, curve 3 shows a drop in the temperature in the container 23, where the heat delivered to the container from the heat source 11 is 15 Watts and the ambient temperature is -3°C. The container 23 had a volumetric capacity of 2 litres in the tests from which these curves were obtained.
Figure 6 is a diagram which shows the curves A4 and M4
representing an increase in the temperature of the vehicle interior and the motor respectively when no heat-insulating container 23 was fitted and when the vehicle was left standing for 10 hours in an ambient temperature condition of -l°C. The curves Al, A2, A3 and Ml, M2, M3 illustrate the temperature increase in the vehicle interior and the motor respectively when the vehicle had been left standing for 2, 3 and 10 hours respectively in an outer temperature condition of -1°C and without supplying additional heat from the heat source 11. It will be seen from the Figure that the engine will have a temperature of 40°C after only some few minutes when the system includes a heat-insulated container in accordance with the invention, wherein when the system includes no such container it takes 6 minutes to reach this temperature. Similarly, when the system includes a container in accordance with the invention, the interior of the vehicle is heated to a temperature of 40°C after only 3 to 4 minutes, whereas it takes up to 8 minutes to heat the vehicle interior to this tem¬ perature when the system includes no such container.
The heat-insulated container 23 shown in Figure 7 is filled with a liquid which is heated by the heating coil 14, which is drawn through the container and through which the vehicle coolant circulates and heats the liquid present in the container. The inner wall of the container is insulated with alternating layers of super¬ imposed foils M and P, as illustrated by the enlarged view of Figure 9. Also drawn through the container 23 is a loop 16 which extends from the vehicle container that contains windscreen and headlamp washing liquid. The heat source 11 connected to the vehicle battery and assisting in maintaining the temperature of the liquid in the container 23 when the engine of the vehicle is switched off is controlled by the thermostat T.
It is preferred to mount the container 23 vertically in the vehicle, as shown in Figure 7, so that the inlet and outlet of the coil 14 coincides with the lowermost part of the coil, thereby preventing self-circulation in the coil when the engine is switched off and thereby prevent indirect cooling of the liquid in the container 23 as a result of circulation of the liquid in the coil 14. Figure 10 illustrates a further method of preventing heat drainage through the heat-conducting material of the coil 14. As will be seen from the drawing, the hose or spiral 14 has thinned portions or chokes 24 at those locations where the coil enters and leaves the container 23.