GB2146237A - Apparatus for warming wash liquid for windscreens - Google Patents

Abstract

Apparatus for warming wash liquid for windscreens comprises a flexible plastic heat exchanger tube 8 which is wound around an outer surface of a cooling water circulating hose 3 which connects an engine 1 with a radiator 2, and pipes 9 for connecting the heat exchanger tube 8 with a wash liquid hose 7 through which wash liquid flows from a tank 5 to wash liquid ejecting nozzles 10. <IMAGE>

Description

SPECIFICATION Apparatus for warming window-washer liquid of automobiles This invention relates to an apparatus for warming window-washer liquid of automobiles, which warms the window-washer liquid by utilizing the heat contained in the cooling water for engine.

Winder-washer liquid is used to assist removal of dirt adhering the window glass of automobiles. Such window washer liquid may be pure water or a mixture of water and detergent; it is well known that the cleaning performance of the washer liquid tends to decrease as the temperature becomes lower. It follows, therefore, that the application of the wsher liquid to a window improves the cleaning performance of the washer liquid. However, excessively hot washer liquid is dangerous because it may cause burns on contact with exposed portions of the human body.

In summer the temperature of the washer liquid in automobiles may well be high enough depending on the climatic conditions, but in winter the temperature of the washer liquid may well be lower than the optimum range. The optimum range may be 40 C to 70 C.

Many proposals for heating washer water which utilizes a heat exchanger installed upon an exhaust pipe through which exhaust gas is discharged from engine, have been put forward.

The apparatus described in Japanese Utility Model Publication No. 34662/1978 warms washer liquid by engine cooling water and heats it further by contacting the washer liquid pipe with an exhaust pipe in parallel.

The apparatus described in Japanese Utility Model Publication No. 6987/1972 has a washer liquid pipe wound around the outer surface of muffler and heats the washer liquid by the heat contained in exhaust gas.

It also devises to withdraw the residual liquid to a washer liquid tank.

The apparatus described in Japanese Utility Model Publication No. 34757/1977 uses a copper pipe which is bent reversely many times and is contacted with the outer surface of muffler. Washer liquid flows through the multi-bent copper pipe. It ensures high heat exchange performance, because the area in which the copper pipe and the muffler contacts each other is wide enough.

The apparatus described in Japanese Utility Model Publication No. 41864/1978 has a heat exchanger with half-cylindrical shape attached upon the outer surface of muffler.

An alternative valve is installed to return the washer liquid heated to the boil back into the washer liquid tank.

The apparatus described in Japanese Utility Model Publication No. 52753/1978 makes use of a heat exchange casing made from metal mounted upon the outer surface of a muffler. In the heat exchange casing a fluid passage meanders. While washer liquid flows through the fluid passage, it is heated. Cooling fins are formed upon the upper surface of the heat exchange casing to prevent washer liquid from boiling.

The apparatus described in Japanese Utility Model Laying Open No. 151147/1982 also uses a heat exchanger which is mounted on exchaust pipe in order to heat up washer liquid.

Main purpose of these apparatus in which washer liquid is heated by the exhaust gas is to heat and melt the snow, frost or ice piled on the front window in cold districts. These apparatus do not aim to enhance the cleaning performance of washer liquid. It is desirable that the washer liquid is very hot, because it aims to melt ice or frost. Therefore, in these apparatus heater exchanger is mounted on exhaust pipe and washer liquid is heated by exhaust gas.

The temperature of exhaust gas is about 250 to 300 C. The outer surface of exhaust pipe is as hot as the gas. If the washer liquid stagnates, it may be superheated to the boil.

In order to avoid such a dangerous state, it is necessary to withdraw the heated liquid to the tank and circulate the liquid again from the tank. These apparatus need a complicated circulation device.

In these apparatus the temperature of washer liquid attains 80 C to 100 C.

It is excessively high temperature to enhance the cleaning performance. Such hot washer liquid is danger also. Further there is a difficulty that heat exchanger must resist the high temperature.

If het exchanger is a pipe wound around a muffler, it must be a copper pipe. If heat exchanger is a vacant metallic plate, it must be made from aluminium or brass.

Thus, the apparatus which utilizes the heat contained in the exhaust gas needs a metallic heat exchanger and a device for circulating the washer liquid every time to avoid boiling.

Inventer thought the apparatus must have too complicated construction and may be too expensive.

Proposals have also been submitted for apparatus in which an independent heater is used in order to heat washer liquid.

The apparatus described in Japanese Patent Laying Open No. 99439/1982 installed an additional heater to heat washer liquid. The heater does not always heat the liquid. While a switch for ejecting washer liquid is pushed on, the heater is switched on. This is immune from the danger of an abrupt boiling. However, great current must flow through the heater coil, because the heater must heat up the washer liquid instantly. Even if great current flows through the heater coil, heating is insufficient, because the Joule heat generated by electric current is weak. It wastes gasoline in excess. It is uneconomical.

But the main purpose of the apparatus is to melt frozen ice or piled snow upon a front window. This is a problem at starting time after a long halt of automobiles. It may be unavoidable to use an additional heater, because the engine is cold at starting.

The apparatus described in Japanese utility model laying open NO. 151146/1982 warms the washer liquid by an additional heater.

Inventor thinks these apparatuses comprising an additional heater to warms the washer liquid are undesirable and uneconomical, because they waste large electric power.

Some persons further pursue the technical object to heat up washer liquid. Water is a main composition of washer liquid. Usually water cannot be heated above 100'C as liquid.

In order to heat up washer liquid more than 100 C washer liquid must be heated to eva portion.

The apparatus described in Japanese utility model laying open NO. 20953/1983 utilizes the cooling liquid of engine as washer liquid.

It ejects part of the cooling liquid on the front window as steam.

After cools engine, the cooling medium is evaporated.

Vapour of cooling medium is pressurised.

Pressurised vapour is cooled and liquified in a condenser. Then the liquified cooling medium cools the engine.

The cooling medium cools the engine not only by the specific heat of water but also by the evaporation heat.

In the cooling cycle, hot pressurised steam is geneated. The apparatus ejects the steam onto the front window.

This apparatus requires a specific construction of the automobile. The scope of utilization of the apparatus is limited. Furthermore, window washer steam is dangerous, because the temperature of steam is more than 100'C.

In the apparatus described in Japanese Utility Model Publication No. 28656/1974 adds a new tank with an inner tank in a cycle of the engine cooling water. Washer liquid is introduced into the inner tank and is warmed therein.

To install this apparatus, a hose must be cut in order to connect the tank for heating with a capacity of about one litre between two cut ends of the hose. The washer liquid supply is fed via this tank to the window.

There is another diffiiculty where and how the tank for heating is fixed in the space under the bonnet of an automobile.

Heat exchange efficiency is good because it utilizes a metallic double tank. On the contrary it is too expensive and too bulky. Furthermore, man must work on a big pipe or hose for cooling water. Such an apparatus cannot easily be mounted on a finished automobile.

(b) The apparatus described in Japanese Utility Model Publication No. 13295/1976 (publication date April 27, 1976) warms washer liquid and prepares warm drinking water by the heat. utilizing the heat contained in the cooling water. A large heat exchanger through which two meandering pipes are mounted on a part from an engine to an radiator of the cooling water pipe.

While flow through either of two meandering pipes washer liquid and drinking water become warm.

Because this apparatus requires the large heat exchanger to be installed in a cycle of the cooling water for engine, it must be installed in a process for manufacturing of automobile. Therefore, the problems about the space and about the piping must be considered from the stage for planning of the construction of automobile. Like the former prior art, this apparatus is too bulky to be installed upon a finished automobile. As mentioned above, the main purpose of the apparatus is to make warm water for drinking.

The difficult process for manufacturing and the rise in price may be considered trival to achieve the main purpose.

(c) The apparatus described in Japanese utility model laying open NO. 17850/1982 (date for laying open; January 29, 1 982) has a cooling water pipe with a wide part which seals a tank for washer liquid therein. Because the outer surface of the tank contacts with the hot water which has returned from the engine, the washer liquid in the tank is warmed.

The heat exchange performance is good, because whole of the tank is enclosed by the hot water.

However the wide part of the cooling water pipe must be shaped beforehand. This apparatus must be installed in a process for manufacturing of automobile. It is imposible to add the apparatus on a finished automobile.

Another difficulty is the rise in cost, because it requires a double-shelled tank. Other defect is the rise of the pressure loss of the cooling water.

(d) The apparatus described in Japanese patent laying open NO. 53549/1983 (date for laying open: August 30, 1983) has a large tank in a cycle of the cooling water for engine. The washer liquid is heated by the hot cooling water in the large tank. An heatinsulating material envelops the tank to keep it warm.

Because the heat-insulating material prohibits the temperature of the washer liquid in the tank from lowering, warm washer liquid can be ejected at starting time of the automobile.

However like the former prior art, it is also bulky and expensive. Furthermore the large heat exchanger enveloped by the heat-insulat ing material requires a big additional space to be installed. The apparatus must be installed in a process for manufacturing of automobiles. It is impossible to add it on a finished automobile.

(e) The apparatus described in Japanese patent laying open NO. 12854/1983 (date for laying open; January 25, 1983) has a big rubber hose connecting an engine with a radiator. A spiralled copper pipe through which the washer liquid flows is inserted into the big rubber hose. The washer liquid warmed in the spiralled copper pipe returns into a tank and is accumulated therein.

The purpose of the apparatus is to get rid of frost and frozen ice from the front window at starting. The engine is not hot and the cooling water is cold at starting time. The warm washer liquid which was heated during the former driving and was accumulated in the tank is ejected at the starting time of the next driving.

The apparatus requires a big rubber hose and a spiralled copper pipe to constitute a heat exchanger. The heat exchange performance is bad, because whole of the washer liquid is always circulated between the tank and the heat exchanger. Furthermore it requires an additional pump for circulation of the washer liquid.

Although the washer liquid in the tank is strongly heated and becomes very hot during the former driving, the washer liquid wastes most of the heat while the car stays.

In the long run chilled washer liquid is ejected on the front window plass at starting.

The apparatus brings about little effect on enhancement of cleaning performance.

Besides a new difficult problem happens about sealing between the copper pipe and the holes of hose through which the pipe passes. Furthermore it requires a costly double-walled tank vessel of stainless steel for example to enhance the power for keeping warmth of the tank.

(f) The apparatus described in Japanese utility model laying open NO. 5348/1982 (date for laying open; January 12, 1982) has an additional heat exchange cylinder with a metallic spiralled pipe therein inserted into a cooling water circulating hose which connects an engine with a radiator.

This apparatus is rather simple, because it requires only the heat exchange cylinder in addition.

The heat exchanger cylinder is a metallic cylinder, on both sides of which joint projections are fixed. The ends of the cooling water circulating hose are attached to the joint projections. In the side plates an inlet and an outlet of the spiralled pipe are also perforated.

On the projecting ends of the spiralled pipe the ends of the washer liquid hose are affixed.

The spiralled pipe is made from alminium or copper.

This apparatus may be added on a finished car. This differs from the prior atrs (a)-(e) mentioned previously concerning this point.

However the heat exchange cylinder is bulky yet. It is difficult to install the apparatus into a narrow space under a bonnet. To fix the metallic heat exchange cylinder among metallic devices man must perforate screw holes or must weld the cylinder thereon. It is improper to fix the heavy cylinder by some adhesive agent. Man must partly rebuilt the construction of car in order to install this apparatus.

Even if man fix the heat exchange cylinder, man must cut the cooling water hose and the washer water hose, and must connect the ends with the projecting inlets or outlets of the heat exchange cylinder. Furthermore, the heat exchange cylinder itself is costly.

Heating washer liquid hardly deserve such a difficult work and such a costly device.

In the long run the installation of the apparatus must be considered at the planning step for manufacturing of automobiles. It must be installed in a process of manufacturing. It is not easy to install the apparatus on a finished car.

Consideration of the prior art referred to above leads to the following facts. On the one hand these apparatus have complex construction with many parts and are expensive. On the other hand they can hardly be installed in a finished car, because they require to insert a new heat exchanger in a cooling water circulating pipe.

In whole of the prior art heat exchange is done by inserting spiralled pipe into the cooling water as a whole.

Because the temperature of the cooling water for engine is nearly 80 C to 90on, hot washer liquid about 70 C is easily obtainable, if the washer liquid goes through the spiralled pipe in the cooling water.

But because the spiralled pipe is dipped in a hot cooling water, the pipe must be strong both chemically and physically, and be resistant against heat. Therefore, the spiralled pipe must be made from copper or aluminium.

Washer liquid is not used at all timed, but is ejected intermittently to clean the window glass. The quantity of washer liquid in one shot is about 1 Occ. It is sufficient, therefore, that only a small number of 1 Occ aliquots of washer liquid is kept warm for ordinary use and it is unnecessary to heat the whole of the washer liquid tank.

Moreover, the temperature of the washer liquid need not be more than 80on.

The prior art described above is primarily concerned with the removal of ice, frost or snow from the window, and in consequence, it is necessary to eject washer liquid at a high temperature, but the purpose of the invention is not to get rid of snow or frost, but to heighten the chemical activity of the washer liquid and to enhance the cleaning perform ance. With this in mind it is clear that all the above mentioned prior art have too strong a heat exchanger with excessive power.

According to the present invention, there is provided an apparatus for warming window washer liquid of automobile comprising; a flexible plastic heat exchanger tube 8 which is wound around an outer surface of a cooling water circulating hose 3 which connects an engine 1 with a radiator 3, and joint pipes 9, 9 for connecting the heat exchanger tube 8 with a washer liquid hose 7 through which washer liquid flows from a tank 5 to a washer liquid ejecting nozzle 10.

This apparatus has the following advantages: (a) the structure is simple, (b) the operation for mounting is facile, (c) inexpensive (d) it requires less space for mounting.

Following is a description by way of example only and with reference to the accompanying drawings of methods of carrying the invention into effect.

In the drawings: Figure 1 is a simplified plan view of a forehand of an automobile to demonstrate the construction of this invention.

Figure 2 is a simplifed plan view of the vicinity of an apparatus for warming washer liquid.

Figure 3 is a partially sectioned front view of a heat exchanger tube wound around the outer surface of a cooling water circulating hose.

Figure 4 is a right side view of the same thing.

Figure 5 is an enlarged view of a heat exchanger tube with an elongated-circle section.

Figure 6 is a perspective view of the heat exchanger tube in the state for winding around the cooling water circulating hose.

Figure 7 is an enlarged sectional view of a tube with an elliptical section.

Figure 8 is an enlarged sectional view of a heat exchanger tube with a circular section.

Figure 9 is a partial front view of a heat exchanger tube showing a joint pipe fixed by a tie belt.

Fig. 1 is a simplified plan view of a forehand of an automobile to demonstrate the structure of the invention. Fig. 2 is a simplifed view of the vicinity of the apparatus for warming washer liquid.

An engine 1 is connected with a radiator 2 by two cooling water circulating hoses 3, 4.

Cooling water is heated in the engine 1, flows through the cooling water circulating hose 3, and is cooled in the radiator 2. The cooled water passes through the cooling water circulating hose 4 and returns to the engine 1.

Washer liquid flows from a washer liquid tank 5 to a washer liquid hose 7 by the action of a washer liquid pump 6.

Ordinarily another end of the washer liquid hose 7 used to be connected with washer ejecting nozzles settled before a front window.

However, in this invention a heat exchanger tube 8 intervenes in the middle of the washer liquid hose 7.

Pertinent joint pipes 9, 9 connect the heat exchange tube 8 with the washer liquid hose 7.

A cooling water pump 11 circulates the cooling water among the hose 3, the radiator 2 and the hose 4 in succession.

Washer liquid under pressure flows from the washer liquid tank 5 into the washer liquid hose 7 and stays in the heat exchanger tube 8, in which the washer liquid is warmed.

The warmed washer liquid flows through the washer liquid hose 7, passes washer liquid ejecting nozzles 10. 10 and sprays upon a front window glass.

Fig. 3 is a partially sectioned front view of the heat exchanger hose 8 wound around the outer surface of the cooling wter circulating hose 3.

Fig. 4 is a sectioned right side view of the same. Fig. 5 is an enlarged view of the heat exchanger tube.

The heat exchanger tube 8 is made from flexible plastics. It is not a copper pipe nor an aluminium pipe.

As shown in Fig. 5 the sectional shape of the heat exchanger tube 8 is an elongated circle. Outer half side 12 and inner half side 13 of the tube 8 are symmetric with regard to the neutral line AB in a free state.

The outer half side 12 is part which is exposed outward when the heat exchanger tube 8 is wound in a coil. The outer half side 12 does not contact with the cooling water circulating hose 3.

The inner side 13 is a part which contacts with the cooling water circulating hose 3.

Although both sides 12 and 13 are symmetric in a free state, the inner side 13 may be distorted slightly by a strong stress when the spiralled tube 8 is wound around the hose.

The apparatus of the invention thus comprises; (a) a flexible, plastic heat exchanger tube 8 with a circular or an elongated-circular sectional shape which is wound around an outer surface of a cooling water circulating hose 3 which connects an engine 1 with a radiator 2, (b) two joint pipes 9, 9 for connecting the heat exchanger tube 8 with a washer liquid hose 7 through which washer liquid flows from a tank 5 to a washer liquid ejecting nozzle 10.

The heat exchanger tube may be manufactured from a flexible plastic material according to the following processes.

First by extruding !ong straight tube with a circular or an elongate-circular section is produced.

Next the long straight tube is wound on some round core in a coil under heating. Then the wound tube is cooled, the coil shape of the tube is fixed. From the round core the tube coil is extracted.

Preferably the inner diameter of the tube coil is slightly smaller than the outer diameter of the cooling water circulating hose 3 on which the tube coil will be affixed later.

Then the long tube coil is cut to length corresponding to a unit heat exchanger tube.

The sectional shape of the heat exchanger tube 8 is a circle or an elongated-circle. Here the "elongate-circle" refers both to a distored circle comprising two half-rounds KL, MN and two sides NK, ML connecting the half-rounds as shown in Fig. 5 and to an ellipse as shown in Fig. 7. The example of the heat exchanger tube 8 with a circular section is shown in Fig.

8.

If the sectional shape of a heat exchanger tube 8 is a circle or an elongated circle under free state, the outer side 12 and the inner side 13 may be distorted slightly inward by the action of pressure and heat, when the tube 8 is wound on the hose 3. Such a slightly-distorted sectional shape is also included in "a circle or an elongated circle".

The heat exchanger tube gradually shinks and contacts more tightly to the cooling water circulating hose 3, because the tube is made from thermoplastic material. Therefore, the heat conduction efficiency becomes better.

The material of the heat exchanger tube 8 is a thermoplastic with a certain heat-resistance. For example 6-nylon or 1nylon is most preferable. Besides them polyethylene, polypropylene or polyvinylchloride is also suitable for the material of the heat exchanger tube.

The joint pipes are short plastic or metallic pipes for connecting the heat exchanger tube 8 with the washer liquid hose 7. Shape, structure, size or material of the joint pipes shall be arbitrarily selected to fit both with the heat exchanger tube 8 and the washer liquid hose 7.

Figures, 3, 4 and 6 show a simple example of joint pipes 9. Another example of joint pipe 9 is shown in Fig. 9, which has an ear 15 on the side. The ear 15 has a small hole 16. A tie belt 17 pierces the hole 16 and winds around the cooling water circulating hose 3.

Both ends of the heat exchanger tube 8 is fixed by the tie belts 17.

A great advantage of the invention is the easy installation in a finished car. The straightened end of the coiled heat exchanger tube 8 is contacted with the outer surface of the cooling water circulating hose 3. The coiled heat exchanger tube 8 is then successively wound about the cooling water circulating hose 3.

Because tube 8 has a tendency to contract in a coil, the free end of the tube 8 does not dangle as the tube 8 is wound on the cooling water circulating hose 3 and hence the other free end does not disturb the operation. Fig. 6 demonstrates the half-wound tube 8. The joint pipes 9 may be preliminarily annexed to both ends of the tube 8. Otherwise the joint pipes 9 may be annexed after winding of the tube 8 on the hose 3.

The washer liquid hose 7 is then cut midway and the cut ends of the hose 7 connected with the joint pipes 9.

In practice auxiliary tubes are also available to connect the heat exchanger tube 8 with the washer liquid hose 7.

The heat exchanger tube may be formed with an elongate section as shown in Fig. 5.

The material may be 12-nylon. The shorter inner diameter (corresponding to KL or MN) is 6 mm. The longer inner diameter (corresponding to UW) is 9 mm. The sectional area enclosed by the tube is 46.3 mm2. The tube may be wound in a coil whose inner diameter is 40 mm under heating. When the tube was cooled, the tube was shaped as a coil with 40 mm inner diameter.

This coiled tube is then wound around a cooling water circulating hose whose outer diameter is 50 mm. Full length of the tube coil is about 1.5 m to 2 m. The winding number is about 8 to 11 turns. Inner volume of the tube coil is 69 cm3, if the full length of the tube is 1.5 m. Inner volume is 92 cm3, if the length is 2 m.

If the tube is shaped in a coil with 40 mm inner diameter, the tube can be wound around a hose whose outer diameter is 42 mm to 50 mm.

By the elastic force of the tube coil, tube coil hugs the hose strongly. Besides by probable heating-cycles, thermoplastic tube gradually contracts and contacts more strongly with the hose.

Experiment shows an excellent advantage.

For example when the temperature of the washer liquid stored in the tank is 30 C, the temperature of the washer liquid warmed by this apparatus and ejected from the nozzle is 48 C. The washer liquid obtained by the apparatus is not too hot. But such mild warmth is pertinent for washer liquid.

The apparatus based on the invention has the following advantages.

(a) The construction is simple. Unlike prior arts aforementioned, it requires no doublewalled tank nor complex tank including a spiralled pipe therein.

(b) Installation operation is very facile. Man only winds a pre-coiled heat exchanger tube on an outer surface of the cooling water circulating hose and connects both ends of the tube with the washer liquid hose.

(c) Additional parts are only a coiled heat exchanger tube and an auxiliary hose (if necessary). It is inexpensive.

(d) No additional tank is not mounted into the cooling water circulating hose anywhere.

This apparatus need a little space alone, because it is installed only by winding the coiled heat exchanger tube around the cooling water circulating hose. It is also immune from the difficulty of fixing of parts, which has been a serious problem in all prior arts.

Claims (5)

1. An apparatus for warming window washer liquid of automobile comprising; a flexible plastic heat exchanger tube 8 which is wound around an outer surface of a cooling water circulating hose 3 which con- nects an engine 1 with a radiator 3, and joint pipes 9, 9 for connecting the heat exchanger tube 8 with a washer liquid hose 7 through which washer liquid flows from a tank 5 to a washer liquid ejecting nozzle 10.

2. Apparatus as claimed in claim 1 wherein the heat exchanger tube 8 is made from thermoplastic material.

3. Apparatus as claimed in claim 2 wherein the heat exchanger tube 8 is made from nylon.

4. Apparatus as claimed in claim 1 wherein the joint pipe 9 has an ear 15 with a hole 16, and a tie belt 17 piercing the ear 15 fixed the joint pipe 9 to the cooling water circulating hose 3.

5. Apparatus as claimed in claim 1 and substantially as herein described with reference to and as illustrated in the accompanying drawing.