Prior art There is not known system which like the system of the current invention after starting the engine heats it in order to reach optimum operating temperature and then cools it in order to maintain it.

Regarding the function of cooling the engine for keeping the optimum operating temperature liquid, cooling systems of internal combustion engines with cooling jacket are well known. A considerable part of them consist of circulation pump, radiator and thermostat interconnected by tubes with the input and output of the cooling jacket of the engine in a so called cooling circulation loop, electrical fan and engine running control computer system, which apart from controlling the fuel and/or ignition engine systems, control also the electrical fan by switching it on when a preset temperature of the engine is reached and switching it off when the temperatures falls under another preset value.

The common flow of the known liquid cooling systems for internal combustion engines is that they do not speed up and even slow down to a certain extent the reaching of an optimum operating temperature of the engine after its starting. During the respective period of reaching an optimum operating temperature the engine operation is described with highly increased specific consumption, harmful emissions in the used-up gases and wear, as well as worsen comfort of the vehicle due to the ineffective operation of the compartment heating.

Sutntrrtarv The invention aim is to create a temperature controlling system for internal combustion engine which in case of operating a heated engine works as a cooling system and in case of operating a cold engine-heats it, using the heat of the used-up gases and this way shortens the period of engine heating up to an optimum operating temperature.

The problem according to the invention is solved by a temperature controlling system for internal combustion engine with cooling jacket provided with a circulation pump and a radiator, connected by tubes in a circulation loop filled with cooling liquid, an expansion vessel for the cooling liquid, a DC electrical fan, located in a housing and an engine running control computer system. The system features also a tube for hot air whose end is shaped as a housing encompassing the engine outlet collector while its other end is connected to the housing encompassing the DC electrical fan. The electrical fan is connected to the engine running control computer system that changes the polarity of the current directed to the electrical fan depending on the engine temperature.

In one option of the system the engine outlet collector is ribbed.

In another option of the system on the electrical fan housing there are lamellar valves, so that they let the air only from the internal side towards the external side of the housing.

In another option of the system in the tube for hot air there are lamellar valves that freely let the air from the space around the outlet collector to the electrical fan, and in the opposite direction do not let the air or let it at a decreased rate.

In another option of the system in the tube for hot air there is a valve connected to an electrical actuating mechanism which is connected to the computer system and it is connected with a sensor for the temperature of the used-up gases and/or of the catalyst of the used-up gases.

In another option of the system it includes also shutter blinds or a curtain mounted in front of the radiator. They are connected to an electrical actuating mechanism which is connected to the engine running control computer system.

In other expedient option of the system the circulation pump is set into motion by an electric motor with changing rotation speed which is connected to the engine running control computer system.

It is suitable to install a thermostat in the circulation loop of the system.

In this option the thermostat can be realized as a throttling valve which opens at different extent by an electrical actuating mechanism, which, from its hand, is connected to an engine running control computer system.

The invention solves the problem also by means of a temperature controlling system for internal combustion engine with cooling jacket provided with a circulation pump, a radiator and a double-action three-way thermostat, connected through tubes in a cooling circulation loop, an electrical fan and an engine running control computer system, as well as a by-pass circulation loop realized by by-pass tube and expansion vessel for the cooling liquid. Both circulation loops are filled with cooling liquid. The by-pass tube connecting the output and the input of the engine cooling jacket through the thermostat is broken also by a second radiator. The second radiator is mounted near the outlet collector of the engine and between them there are shutter blinds connected to an electrical actuating mechanism. The later is connected to the engine running control computer system. There is a temperature sensor mounted on the second radiator that is connected to the engine running control computer system. The engine running control computer system is connected as well to a second DC electrical fan. The computer system switches on the second DC electrical fan with different polarity of the current depending on the engine temperature. The second electrical fan is located near the second radiator and around the outlet collector of the engine there is a housing at whose end the second radiator, the shutter blinds and the second electrical fan are mounted.

It is expedient the outlet collector of the engine to be ribbed.

In one option of the system the thermostat is realized as a three-way distribution valve connected to electrical actuating mechanism which, from its hand, is connected to the engine running control computer system.

In another option of the system the circulation pump is set into motion by an electrical motor with variable rotation speed, connected to an engine running control computer system.

In another option of the system the computer system is connected to a sensor for the temperature of the used-up gases and/or of the catalyst of the used-up gases.

The advantages of the system according the invention in all of its options described above, are that in the period of reaching an optimum operating temperature of the engine, the system provides heating of the cooling liquid through blowing the radiator with air having been heated by the outlet collector of the engine. Thus the system shortens the period of reaching an optimum operating temperature of the engine. Therefore, the fuel consumption decreases, as well as the amount of harmful emissions in the used-up gases and the wear of the engine both in usual cycles of city traffic and in the standard European, American and Japanese cycles for measuring fuel consumption and quantities of harmful emissions of vehicles in case off imitation of city traffic. In the cases when the cooling liquid is used for some heating system, e. g. of the compartment of the vehicle, speeding up the heating of the cooling liquid, the system allows speeding up the effective operation of the heating system and that way increases the comfort of the vehicle. After reaching an optimum temperature of the engine, the system maintains it working like the widespread liquid cooling systems. The system options described above provide additionally the possibility for maintaining different optimum temperatures of the engine in different modes of loading and rotation frequency due to the fact that the engine running control computer system in these options controls at least one element from which the engine cooling depends on-the circulation pump or the throttling (respectively, the distribution) valve in the circulation loop (respectively, between the two circulation loops).

Brief desertption of the drtniiligs Figure 1 shows a drawing of the system according to the invention in the option with lamellar valves on the housing, encompassing the DC electrical fan and with an electrical motor for setting into motion the circulation pump.

Figure 2 shows a drawing of the system according to the invention in the option provided with a thermostat and with shutter blinds with electrical actuating mechanism and lamellar valves in the hot air tube.

Figure 3 shows a drawing of the system according to the invention in the option provided with thermostat realized by throttling valve with electrical actuating mechanism and with shutter blinds with electrical actuating mechanism, as well as with a valve in the hot air tube, an electrical actuating mechanism for setting the valve into motion and a sensor for the temperature of the used- up gases and/or the catalyst.

Figure 4 shows a drawing of the system according to the invention in the option with two circulation loops and with a double-action three-way thermostat.

Figure 5 shows a drawing of the system according to the invention in the option with two circulation loops and with a double-action three-way thermostat realized as a distribution valve connected to an electrical actuating mechanism.

Preferred embodiment As it can be seen from figure 1, the temperature controlling system for internal combustion engine with cooling jacket 1 includes a circulation pump 2, a radiator 3 and tubes 4 connected in a circulation loop, an electric motor 5, a DC electrical fan 6 located in a housing 7, an engine running control computer system 8, a hot air tube 9, which has a complex transverse and longitudinal section. One of the ends of the tube 9 encompasses the outlet collector 10 of the engine 1 like a housing, while the other end is connected to the housing 7 around the DC electrical fan 6. On the housing 7 of the electrical fan 6 and/or the hot air tube 9 lamellar valves 11 could be located that let the air only from the internal side to the external side of the housing, respectively the hot air tube.

The electrical fan 6 is connected to the computer system 8 in such a way that the later changes the polarity of the current directed to the electrical fan depending on the temperature of the engine. The circulation pump 2 is connected to the electric motor 5, which is connected to the computer system 8. The system has also an expansion vessel for the cooling liquid, which is not shown on the figure.

The multitude of sensors passing signals about the temperature of the engine and/or the liquid in different points, the temperature of the air sucked by the engine, the position of the accelerator pedal, the presence of detonation, the revolutions and the position of the engine shaft, the contents of oxygen in the used-up gases, etc. to the computer system 8 are not shown either.

In the option shown on figure 2 the system includes additionally lamellar valves 12, shutter blinds or a curtain 13, an electrical actuating mechanism 14, which could be step-by-step electric motor, and a thermostat 15. In this option the computer system 8 is described as being connected also to the step-by-step electric motor 14 of the shutter blinds/curtain 13 and the computer system switches it on and off depending on the temperature of the engine. The thermostat 15 is of the widespread type with unilateral action and it is mounted in the circulation loop.

In the option shown on figure 3 the thermostat is realized as a combination between a throttling valve 16 connected to an electrical actuating mechanism 17, which could be step-by-step electric motor, and which, on its hand, is connected to the computer system 8. In the hot air tube there is a valve 18 connected to an electrical actuating mechanism 19, which is connected to the computer system 8, and the system is connected to a sensor 20 about the temperature of the catalyst 21 of the used-up gases.

In the option shown on figure 4 the temperature controlling system for internal combustion engine with cooling jacket 1 includes a circulation pump 2, a radiator 3 and a double-action three- way thermostat 22 connected through tubes 4 in a cooling circulation loop and through a by-pass tube 23 they are connected also in a by-pass circulation loop, a DC electrical fan 6 and a engine 1 running control computer system 8. The by-pass tube 23 is broken by a second radiator 24. It is mounted near the outlet collector 10 of the engine 1. Between them there are shutter blinds 13 connected to an electrical actuating mechanism 14 that could be step-by-step electric motor. It is connected to the computer system 8 which is connected also to a second DC electrical fan 25. The computer system 8 switches on the electrical fan 25 with different polarity of the current depending on the temperature of the engine 1. The temperature sensor 26, connected to the computer system 8 is mounted on the radiator 24. The radiator 24, the electrical fan 25 and the shutter blinds 13 are mounted in a housing 27 which encompasses the outlet collector of the engine. The system has also an expansion vessel for the liquid, which is not shown on the figure. The multiple sensors passing signals about the engine 1 operating conditions to the computer system 8 are not shown either.

In the option shown on figure 5 the double-action three-way thermostat is realized as a three-way distribution valve 28, connected to an electrical actuating mechanism 29, which could be also a step-by-step electric motor.

The system operates as follows: After starting the internal combustion engine 1 the circulation pump 2 sets into motion the cooling liquid along the circulation loop consisting of itself, the cooling jacket of the engine 1, the radiator 3 and the tubes that connect them 4. The computer system 8 identifies by means of at least one temperature sensor (which is not shown on the figure) the temperature of the engine 1. If it is lower than the optimum one, the computer system 8 switches on the electrical fan 6 with such a polarity of the current that it rotates in a direction where it sucks air through the hot air tube 9 from the space around the outlet collector 10 of the engine 1 and with this air blows the radiator 3. The lamellar valves 11 of the housing 7 of the fan 6 do not allow sucking cold air from the external side of the housing 7. That way the fan 6 sucks only air which has been heated by the outlet collector 10 of the engine 1. By ribbing the outlet collector 10 the heat transfer from it to the air sucked by the fan 6 is enhanced. With the sucked hot air the fan 6 blows the radiator 3 and heats it together with the cooling liquid in it. The later gives heat during the circulation to the cooling jacket of the engine 1 and that way speeds up its heating. When a specified lower limit of optimum temperature of the engine 1 is reached, the computer system 8 switches off the electrical fan 6 and that way the heating of the radiator 3 with hot air is stopped. Then the system continues its operation like a liquid cooling system with one circulation loop. The cooling liquid is cooled in the radiator 3 as a result that the later is not blown by hot air. Usually this cooling is not sufficient and the temperature of the engine 1 keeps on rising. When it reaches a specified value close to the upper limit of the optimum temperature the computer system 8 switches on again the fan 6, but with the opposite polarity of the current. As a result of that it revolves in the opposite direction and sucks through the radiator 3 cold ambient air that cools the radiator 3 and as a consequence-the engine 1. In this direction of air movement the lamellar valves 11 let it freely from the internal to the external side of the housing 7 of the fan 6. Thus the movement of the cooling air is not made difficult by the respectively smaller passing section of the tube 9. The air moving along the tube 9 blows the outlet collector 10 of the engine 1 and thus cools it. Therefore the catalyst of the used-up gases is being protected against overheating in case that the engine 1 is equipped with such device.

By subsequent switching on/off of electrical fan 6 with one or another polarity the radiator 3 is being blown by hot air, is not blown or it is blown by cold air. That way the temperature of the engine is kept in the range between the specified lower and upper limit of optimum temperature.

In the case of the forth option of the system which has been described, the lamellar valves 12 provided for it (which could be seen on figure 2) in the hot air tube 9 obstruct partially or in entirely the movement of the air from the fan 6 through the hot air tube 9 to the outlet collector 10 of the engine 1. Thus the cooling of the outlet collector is limited and overcooling of the used-up gases under the temperature needed for normal operation of the catalyst, if any, is not allowed.

In the case of the fifth option of the system which has been described, the sensor 20 for the temperature of the used-up gases and/or the catalyst 21 passes signals to the computer system 8. If the temperature of the used-up gases and/or the catalyst 21 is lower than the lower limit of the temperature needed for optimum operation of the catalyst 21 and in the same time the temperature of the engine 1 is within the limits of its optimum temperature, the computer system 8 by means of the electrical actuating mechanism 19 closes the valve 18. Thus air movement from possibly working fan 6 to the outlet collector 10 is obstructed, which, from its hand, protects the used-up gases from overcooling and ensures normal operation of the catalyst 21. In case of excessive temperature of the used-up gases and/or the catalyst 21, the computer system 8 opens by means of the electrical actuating mechanism 19 the valve 18 and simultaneously switches on the electrical fan 6. The polarity of this switching depends on the temperature of the engine 1. If it is lower than the lower limit of the optimum temperature, the polarity is such that the fan 6 blows in the direction from the outlet collector 10 to the radiator 3. If the temperature of the engine is above the lower limit of the optimum temperature, the polarity and respectively the direction of blowing of the fan 6 are the opposite. In all cases when the temperature of the engine 1 is lower than a specific lower limit, the computer system 8, by means of the electrical actuating mechanism 19, keeps the valve 18 opened.

The sixth option of the system which has been described, is suitable for vehicles where the radiator 3 is blown by the opposite air when moving. The shutter blinds or curtain 13 provided in this case and the electrical actuating mechanism 14 that sets them into motion, which could be a step-by-step electric motor, act in the following way. When the system starts working in the mode of heating the engine 1, the computer system 8, by means of the step-by-step electric motor 14, closes the shutter blinds (or the curtain) 13. Thus the closed shutter blinds or the curtain 13 do not allow the opposite cold air flow to obstruct the hot air flow moving through the radiator 3 in opposite direction under the impact of the electrical fan 6. When the lower limit of the optimum operating temperature of the engine 1 is exceeded, the computer system 8, by means of the step-by- step electric motor 14 opens the shutter blinds/curtain 13 to a certain extent according to the temperature of the engine 1 and the program of the computer system 8. When a value close to the upper limit of the optimum operating temperature of the engine 1 is reached, the shutter blinds/curtain 13 open fully and ensure maximum access of the opposite cold air to the radiator 3.

In this option of the system the electrical fan 6 is switched on and operates according to the same algorithm as in the previous options.

In the case of the seventh option of the system which has been described, the operation of the system and respectively, the heating or cooling of the engine 1, is controlled additionally in the following manner. The computer system 8 controls the rotation speed of the electric motor 5, setting the circulation pump 2 into motion. Thus the circulation speed of the liquid is regulated and, respectively, the intensity of cooling and as a result-the temperature of the engine 1. It is typical for this option that in the programs of the computer system 8 different lower and upper limits of the optimum temperature of the engine 1, corresponding to different modes of its operation, could be set.

In the case of the eight option of the system which has been described, the operation of the system is regulated additionally by the inbuilt thermostat 15. It is of the known type with unilateral action and works according to the well-known way. Its never stops entirely the circulation of the cooling liquid, only delays it at temperatures of the engine 1 lower than the upper limit of the optimum temperature. Thus the needed circulation of the liquid is ensured, even at low temperature of the engine 1, necessary for the operation of the system in a mode for heating the engine 1. The delayed circulation is necessary for relatively smaller amounts of heat that are transmitted in the mode of heating and non-intensive cooling and at the same time the consumed power by the circulation pump is decreased.

In the case of the ninth option of the system which has been described, the thermostat is realized as a throttling valve 16, set into motion by an electrical actuating mechanism 17, which could be a step-by-step electric motor, and which is controlled by the computer system 8. Like the seventh option, this option allows different optimum temperatures of the engine 1 at its different operation modes, which is achieved by respective programming of the computer system 8 regarding the opening of the throttling valve 16. For example, keeping higher temperatures at low loading of the engine 1 can be set, as well as keeping lower temperatures at high loadings.

In the case of the tenth option of the system which has been described, which can be seen on figure 4, the option is the same as in the previous options, but with the following particularities.

The thermostat 22 is of the widespread type of double action three way thermostat. At temperatures of the engine 1 lower than the lower limit of the optimum operating temperature the thermostat 22 allows circulation of the cooling liquid only through the by-pass circulation loop formed by the by- pass tubes 23, the radiator 24 and the thermostat 22. Then the computer system 8 switches on the electrical fan 25 to work in such direction that it sucks through the radiator 24 hot air from the space around the outlet collector 10, formed by the housing 27. In case of exceeding the lower limit of the optimum temperature, the thermostat 22 starts gradually to let the liquid circulate even through the main radiator 3 and in the same time decreases the circulation through the by-pass loop. Simultaneously, the computer system 8 stops the electrical fan 25 and through the step-by- step electric motor 14 closes the shutter blinds 13. Then the system works practically like the widespread liquid cooling systems with by-pass loop and double-action three-way thermostat.

When specified temperatures, close to the upper limit of the optimum temperature, are reached, the computer system 8 switches on the electrical fan 6, and the thermostat 22 limits the circulation of the liquid through the by-pass loop to a certain minimum. In case that the temperature of the liquid in the radiator 24 reaches a specific value above the upper limit of the optimum temperature, the sensor 26 gives the respective signal to the computer system 8, which as a result of that switches on the electrical fan 25 in direction opposite to the initial one. Simultaneously, the computer system 8, by means of the step-by-step electric motor 14, opens the shutter blinds 13. Thus the electrical fan 25 blows the radiator 24 and the outlet collector 10 of the engine 1 ; this way it helps the cooling of the engine 1, does not allow the liquid in the radiator 24 to boil and prevents the catalyst of the used-up gases from overheating, if the engine 1 is provided with such.

In the case of the twelfth and thirteenth option of the system, the system operates as in the tenth option with the following particularities. In the case of the twelfth option the thermostat is realized as a three-way distribution valve 28, set into motion by an electrical actuating mechanism 29, that could be step-by-step electric motor, and that is commanded by the computer system 8.

Like the seventh and the ninth options, this option allows through respective programming of the computer system 8 to maintain different optimum temperatures of the engine 1 in the different operation modes. In the thirteenth option the circulation pump 2 is set into motion by an electric motor 5, as it is shown on figure 1, and the computer system 8 controls its rotation speed. Thus the speed of the circulation of the cooling liquid and respectively the intensity of the heating/soc1ulg of the engine 1 and its temperature are regulated. For this option it is typical that in the programs of the computer system 8 could be set different lower and upper limit of the optimum temperature of the engine 1, corresponding to its different operation modes.

In the case of the fourteenth option of the system, the computer system 8, switches on the electrical fan 25 and opens the shutter blinds 13, by means of the electrical actuating mechanism 14 apart from the other cases described, also in the cases when the temperature of the used-up gases and/or the catalyst 21, according to the readings of the sensor 20 (shown on figure 3), exceeds the optimum values for operation of the catalyst 21. The polarity of the switching the fan 25 in these cases depends on the temperature of the engine 1. In case of temperature lower than the optimum temperature of the later, the polarity of switching is such that the fan 25 blows in the direction from the outlet collector 10 to the radiator 24. In case of temperatures higher than the optimum temperature of the engine 1, the polarity of switching is the opposite.