JPH05202750A - Evaporative cooling type internal combustion engine - Google Patents

Abstract

PURPOSE: To obtain an evaporative cooling-type internal combustion engine wherein a cooling liquid temperature and a pressure in a cooling system can be individually controlled. CONSTITUTION: An internal combustion engine according to the present invention is an evaporative cooling-type internal combustion engine comprising a cooling system allowing loading of a pressure and passing of a cooling liquid. This engine further comprises at least a condensate cooler, at least a cooling liquid pump and at least an expansion tank. The expansion tank is connected to a cooling circulation path via a connecting pipe. The expansion tank 4 is arranged just before the cooling liquid pump 11 in a main flow direction 9, and a convection cooler 7, which is attached to the condensate cooler 3 and capable of input via a thermostat 6, is provided. Then, the cooling liquid from a convection cooler and the condensate from the condensate cooler are integrated with each other at a node in a delivery pipe reaching the internal combustion engine 1. A pumping device for sending the cooling liquid in a main flow direction 9 is arranged in the node region, and a pressure adjusting valve 10 is arranged between the pumping device and an outlet of the condensate cooler in the main flow direction 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporative cooling type internal combustion engine including a cooling system capable of applying a pressure and allowing a cooling liquid to flow therethrough, wherein at least one condensate cooler and at least one cooling liquid pump are provided. And one expansion tank, the expansion tank being connected to the cooling circuit by a connecting pipe.

[0002]

Such an internal combustion engine is known from US Pat. No. 4,648,356. There, the cooling system is essentially composed of a water jacket of an internal combustion engine, a radiator configured as a condensate cooler, a condensate tank, and a tank divided into two partial chambers by a partition wall. The room away from the system is open to the atmosphere. The role of this device is to temporarily extract the air in the closed system from the system and keep it away from the condenser to improve the efficiency of the device. The mixed air, which is detrimental to the function of the system, accumulates in the tank when the internal combustion engine warms during operation, and is sent back to the system when the engine cools to prevent the generation of negative pressure.

[0003]

However, it should be noted that the mass flow rate passing through the condenser and the steam content before the condenser should be controlled in order to achieve optimum condenser cooling performance. I have to. This is not possible with known internal combustion engines.

Further, here, as a drawback, it is not possible to individually control the coolant temperature and the system pressure of the cooling system. It is not possible with known internal combustion engines to match the cooling performance of the condenser cooling device with the heater performance of the engine.

The object of the present invention is to improve an evaporatively cooled internal combustion engine of the kind mentioned at the outset, so that the coolant temperature and the system pressure inside the cooling system can be controlled individually. Furthermore, the circulation of the cooling fluid flowing through the cooling system and the internal combustion engine connected to it must be optimized, especially when the heater performance of the internal combustion engine is high and the associated flow losses are high.

[0006]

According to the invention, an object of the invention is an evaporative cooling type internal combustion engine including a cooling system which can be loaded with pressure and can flow a cooling liquid, and at least one condensate cooler. In the case where at least one cooling liquid pump and one expansion tank are provided, and the expansion tank is connected to the cooling circuit by a connecting pipe, the expansion tank is arranged immediately before the cooling liquid pump in the main flow direction, and A convection cooler that can be charged via a thermostat is attached to the cooler, and the cooling liquid from the convection cooler outlet and the condensate from the condensate cooler outlet are connected at a node in the feed pipe to the internal combustion engine. In general, a pumping device for sending the cooling liquid in the main flow direction is arranged in the nodal point range, and a pressure regulating valve is arranged between the condensate cooler outlet and the pumping device in the main flow direction. Achieved by the institution. The dependent claims relate to advantageous configurations.

The internal combustion engine according to the invention has an expansion tank, which is arranged immediately before the coolant pump in the main flow direction and is provided with a convection cooler which is attached to the condensate cooler and which can be turned on via a thermostat. The condensate from the outlet of the convection cooler and the condensate from the outlet of the condensate cooler are combined at a node in the feed pipe leading to the internal combustion engine, and a pumping device that sends the coolant in the main flow direction. Are placed in the nodal point range. 1 By using a condensate cooler and a convection cooler inside the cooling system, it is possible to achieve system pressure adjustment using a pressure regulating valve arranged behind the condensate cooler outlet in the main flow direction. The system pressure can be adjusted according to the traveling speed, ambient temperature and engine operating point. The coolant temperature and system pressure can be adjusted individually for this system.

The system pressure is adjusted by the control valve at the condenser outlet. This valve controls the flow rate of the condenser and thus its cooling performance, depending for example on the pressure in the engine. By matching the cooling performance with the heater performance of the engine, the pressure inside the cooling system can be kept constant. By individually adjusting the system pressure and the coolant temperature, it is possible to exert a particularly good influence on the control of the member temperature, in which case the member temperature in the cylinder head range is particularly important. The pressure regulating valve can be connected, for example, in signal transmission with a pressure sensor in the cylinder head or at the condenser outlet. The valve controls the condensate flow rate through the condenser to ensure the required cooling performance and the preferred component temperature. The boiling temperature of the cooling liquid depends on the pressure in the cooling system, and this pressure can be adjusted by this valve.

According to one advantageous configuration, the pumping device is formed by a Venturi tube and is capable of supplying condensate in the region of the narrowest flow passage cross section in the Venturi tube. The use of a Venturi tube as a pumping device is advantageous, in particular because the cooling system has a simple structure and avoids, for example, an electrically driven second cooling liquid pump, which is very important from an economic point of view.

The Venturi tube, which forms a node that brings together the coolant from the convection cooler and the condensate from the condensate cooler, is further based on the flow loss between the internal combustion engine and the condensate cooler. The condensate is not pushed back into the condensate cooler, but rather is entrained in the main flow direction and fed to the internal combustion engine. This configuration results in a very favorable efficiency due to the high volumetric flow through the cooling system with only one coolant pump, which is also particularly advantageous from an economic point of view. By using the Venturi tube in the cooling system of the evaporative cooling type internal combustion engine, the cooling liquid pump can be selected extremely precisely in terms of size. Also in this case, the ejection performance is quite sufficient. The thermostat releases the paths of the various cooling circulation paths according to the temperature of the cooling liquid or the member temperature determined by the temperature sensor. During the warm-up phase of the internal combustion engine, the path through the convection cooler is blocked, which results in rapid heating of the internal combustion engine. As the temperature rises, the thermostat gradually opens its path through the convection cooler, and the internal combustion engine is reliably prevented from being damaged by overheating. A further advantage is that by placing the condensate cooler and the convection cooler in parallel, the cooling liquid is fed into the internal combustion engine at an almost constant inlet temperature. This configuration essentially reduces the risk of thermal stresses in the relatively hot internal combustion engine, for example due to the relatively cold condensate.

According to an advantageous configuration, the Venturi tube can be formed by a T-shaped pipe coupling element. The pipe connecting element configured in this manner can be manufactured particularly favorably from an economical point of view, and enables various shapes of pipe connecting. At that time, the constriction in the shape of the venturi nozzle is in the main flow direction, and the branch is provided in the area of the smallest flow passage cross section, and this branch should be connected to the outlet of the condensate cooler in a liquid conduction manner. You can

The expansion tank and the supply port provided with the ventilation portion can be integrated into a structural unit and fixed to each other in a liquid-conducting manner via a connecting pipe. This configuration ensures a simple and clear structure of the cooling system. The cooling liquid, which in most cases consists of water and the antifreeze, can be injected very easily in this way. This also simplifies the maintenance and monitoring of the cooling system regarding possible leaks.

For easy and correct injection into the cooling system, a restrictor can be arranged in the connecting pipe between the stiffening port and the expansion tank, which restricts the liquid flowing through the conduit. The expansion tank can be divided into a cooling liquid containing chamber and an expansion chamber by a separation diaphragm, the expansion chamber is connected to the atmosphere through a ventilation hole, and the separation diaphragm can be loaded only by the atmospheric pressure. According to another configuration, a spring element is arranged inside the expansion chamber and the spring element is configured, for example, as a compression coil spring,
It is possible that one end is supported by the housing of the expansion tank and the other end is supported by the side surface of the separation diaphragm facing the expansion chamber. The functional style is basically the same. If the cooling liquid pump is appropriately designed, this pump together with the throttle can make it possible to bring the separation diaphragm into contact with the bottom dead center of the expansion tank while injecting the cooling liquid into the cooling system. This makes it unnecessary to use, for example, a spring in the expansion chamber.

An in-vehicle heater may be arranged in the cooling system, in which case the in-vehicle heater is arranged in a zone of the cooling system in which only the steam is filled while the internal combustion engine is used as specified. The advantages here are that the internal combustion engine is heated particularly quickly, the optimum operating temperature is reached quickly, the fuel consumption is low and the emission of harmful substances is low.

When the operating temperature is reached and some of the cooling liquid is vaporized, the heater can be activated, providing heater performance far exceeding that of in-vehicle heaters located in the water circuit. As a further advantage, a more uniform, speed-independent heater performance is guaranteed. The fact that the heater can be started only after a part of the cooling liquid is vaporized is not a serious drawback in practical use. This is because the heater arranged in the water circulation path also releases heat for heating the room only when the cooling liquid reaches a certain temperature.

In order to further improve the efficiency of the cooling system, a water separator can be provided in the cooling liquid outlet region of the internal combustion engine, the separator having only a large amount of water in the convection cooler even if the cooling liquid volume is large. , And allow the condensate cooler to pass only steam. One particularly advantageous configuration is achievable when the cooling liquid can be fed into the internal combustion engine in the region of the cylinder head and the internal combustion engine acts as a separator. The advantage to be emphasized in this respect is that no harmful vapor nests are produced, in particular in the cylinder head by the minimum scavenging of the engine. In this case, the minimum scavenging is greater than the optimum mass flow for performance through the condenser. Good cooling efficiency is possible only with efficient and controlled separation of water and steam. Furthermore, the separation of water and steam inside the engine does not create additional throttling resistance, additional expansion volume for external separators, and additional components with piping. In this case, cold cooling liquid is supplied into the internal combustion engine within the range of the cylinder head, steam escapes upward in the direction of the condenser, and cooling liquid flows downward into the internal combustion engine to allow the engine to flow through the engine. .. The internal combustion engine thus acts as a separator.

According to another configuration, a liquid-tight partition wall which is attached to the compensating tank and which moves relatively can be provided, and this wall partitions the compensating tank into a cooling liquid containing chamber and a spring chamber, and the spring chamber. Is connected to the suction device of the internal combustion engine by means of a vacuum line, which can be closed by at least one shut-off valve. In this case, a suction device is provided as a prerequisite,
This also provides the negative pressure for proper operation of the partition. If the internal combustion engine is a diesel engine, the vacuum line can advantageously be connected to the vacuum pump of the braking system. In evaporative cooling, the boiling temperature of the cooling liquid is determined according to the pressure in the cooling system. Depending on the high system pressure in the cooling system and the various coolant boiling temperatures associated with it, the component temperatures of the internal combustion engine can be optimally adapted to the respective load conditions. By diverting the partition walls in the compensation tank, the total volume of the cooling system and thus the system pressure is adjusted depending on the operating point of the internal combustion engine. The desired system pressure can be determined, for example, from the following parameters: coolant temperature, component temperature, negative pressure in the suction pipe, throttle valve position, internal combustion engine speed, fuel injection quantity, ambient temperature and / or vehicle speed. In the case of electronically controlled internal combustion engines, a large number of the abovementioned auxiliary quantities are provided in any case, so that no additional sensor is required,
This gives a very good reliability of the cooling system. A negative pressure reservoir can be additionally provided in association with the negative pressure pipe. This is particularly significant when the suction device of the internal combustion engine does not provide sufficient negative pressure to adapt the system pressure in the cooling system to the respective load condition under any load condition. .. When operating at no load, i.e. when a relatively high system pressure is required, which requires a high boiling temperature and thus a rapid heating of the internal combustion engine, the suction device provides a high negative pressure without a negative pressure reservoir, while In the load range, i.e. when low system pressure and low coolant boiling temperature are required to avoid overheating of the internal combustion engine, the suction device produces only a slight negative pressure. This relatively low negative pressure may in some cases not be sufficient to reduce the system pressure in the cooling system to allow operation of the internal combustion engine without the risk of overheating. To prevent these drawbacks, a negative pressure reservoir can be provided which ensures that at each operating point of the internal combustion engine a sufficient negative pressure is provided to the spring chamber in the compensation tank.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an evaporative cooling type internal combustion engine according to the present invention are schematically shown in the accompanying drawings and will be described in detail below.

1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, and FIG. 6 respectively show an evaporative cooling type internal combustion engine 1, in which a cooling liquid can flow into a cooling system 2 which can be loaded with pressure. Is.
The cooling liquid is often water containing antifreeze. The compensation or expansion tank 4 is connected by a connecting pipe 5 to a zone of the cooling system 2 which is always filled with the cooling liquid during the operation of the internal combustion engine 1. The cooling system 2 essentially comprises a condensate cooler 3, a pressure regulating valve 10 arranged behind the condensate cooler 3 in the flow direction, and a convection cooler 7 arranged in parallel with each other.
The cooling liquid outlet of the convection cooler 7 and the condensate outlet of the condensate cooler 3 are combined into one node, and this node is shown in FIGS.
Is formed by the Venturi tube 8. The cooling liquid flows through the venturi pipe 8 in the main flow direction 9 at a relatively high speed in the minimum flow passage cross-sectional range, and carries the condensate generated in the condensate cooler 3, and if necessary, the cooling liquid from the compensation tank 4. Is carried based on the pressure drop at this point. When the heater performance of the internal combustion engine 1 is high and the volume flow through the cooling system 2 is high, backflow of the cooling liquid and the condensate into the condensate cooler 3 is eliminated by the arrangement of the venturi pipe 8. As a result, the throttling effect does not appear in the cooling system 2, so that the cooling performance and efficiency of the cooling system 2 are considerably improved.

The convection cooler 7 brings the cooling liquid supplied into the internal combustion engine 1 to a substantially uniform temperature. This temperature is designed so that the generation of vapor bubbles is effectively prevented in the range of the venturi pipe 8 and the cooling liquid pump 11. As a result, the functional reliability and service life of the cooling system 2 are significantly increased.

The system pressure of the cooling system 2 can be adjusted by the pressure load of the compensation tank 4. When the system pressure is high, the boiling temperature of the cooling liquid flowing through the cooling system 2 is high, and when the system pressure is relatively low, the boiling temperature is low. Internal combustion engine 1
In the cold state, that is, before or immediately after the start of operation, the cooling system is completely filled with the cooling liquid and there is no steam.
The volume of the cooling liquid containing chamber 16 of the compensation tank 4 is the smallest.

The evaporative cooling type internal combustion engine 1 according to the present invention shown in FIG. 1 has just started after the cooling system 2 is free of steam and has not yet reached its optimum operating temperature. Both the convection cooler 7 and the condensate cooler 3 are completely filled with the cooling liquid. Thus, the risk of damage to the radiator by freezing does not occur even when the outside air temperature is extremely low. In this operating state, the steam pipe 20 is also filled with the cooling liquid. The characteristic of the system pressure depends on the spring characteristic of the spring in the spring chamber 17. Compensation tank 4
Has a hole on the side remote from the cooling liquid, which hole communicates this chamber with the atmosphere. A portion of the Venturi tube 8 is shown as detail "X". However, apart from the embodiment shown here, it is also possible to load only the atmospheric pressure inside the compensation tank 4 instead of loading the separating diaphragm with a spring.

The cooling system shown in FIG. 2 is the same as the cooling system shown in FIG. 1. In this case, the operating temperature of the internal combustion engine 1 rises and a part of the cooling liquid is already vaporized. Only the vaporized cooling liquid exists in the steam pipe 20. The volume displaced by the steam is compensated by the cooling liquid containing chamber 16. In doing so, it is of course necessary to pay attention to the dimensions of the compensating tank 4 adapted to this system. In the water circuit, in this case there is an in-vehicle heater 12 in front of the convection cooler 7. The oil heat exchanger 13 is also arranged in the cooling liquid pipe. If the in-vehicle heater 12 is arranged in the water circulation path, the interior of the vehicle is heated quickly during its operation, and the warm-up stage of the internal combustion engine becomes relatively long. Compensation tank 4 partition wall 4.3
Is displaced in the direction of the spring chamber 17, and the liquid component displaced by the vapor can be received in the cooling liquid containing chamber 16. In addition to the system shown in FIG. 1, the spring chamber 17 is connected to a negative pressure pipe 18 via a shutoff valve 19, and the negative pressure pipe is connected to a suction device of an internal combustion engine. In this case, the pressure load of the cooling system 2 can be controlled more sensitively than in the case of FIG. In order to lower the system pressure and lower the boiling temperature by preparing a sufficiently high negative pressure during full load operation of the internal combustion engine 1, a negative pressure reservoir may be arranged in the negative pressure pipe 18 in some cases.

In an internal combustion engine similar to that shown in FIG. 2 shown in FIG. 3, the in-vehicle heater 12 is not arranged in the liquid flow circulation path of the cooling system 2, but only steam can flow through. This configuration has the advantage that the internal combustion engine 1 reaches its operating temperature sooner, which is advantageous in terms of low wear, low fuel consumption and more favorable emission of harmful substances. The in-vehicle heater 12 is effective only when some of the cooling liquid has already vaporized, and is characterized by a significantly improved heater performance in this case. The pressure loading of the cooling system is again effected by the spring in the spring chamber 17 of the compensation tank 4 in this embodiment, the spring chamber 17 and the atmosphere being in communication through a hole. It is also conceivable that the separation diaphragm is not loaded with a spring force inside the compensation tank 4.

To improve efficiency, a water separator 14 can be provided, as shown in FIG. 4, so that water is exclusively sent to the convection cooler and steam exclusively to the condensate cooler. To

In terms of the mode of operation, the evaporative cooling type internal combustion engine 1 shown in this figure does not differ from that described above.

In the evaporative cooling type internal combustion engine 1 shown in FIG. 5, the compensation tank 4 is formed integrally with the replenishment port 15. When the heating of the cooling liquid is increased and steam is generated, the liquid level in the compensation tank 4 rises from the minimum value to the maximum allowable value. A float valve 4.2 is placed in the maximum permissible range, which closes the opening towards the atmosphere when the maximum permissible liquid level is exceeded. During the warm-up phase, the liquid level rises to its maximum as steam generation increases. Furthermore, it is also very important that the injection of the cooling system is particularly easy. Even if the coolant is filled up to the highest mark of the supply port 15, the required expansion volume is guaranteed inside the compensation tank 4 nevertheless. Handling such a cooling system 2 is particularly simple.

The embodiment shown in FIG. 6 is similar to that described above. The expansion tank 4, the supply port 15 and the negative pressure throttle 22 are combined in this embodiment into one structural unit, and a second cooling liquid pump 11.2 is used directly in the range of the expansion tank 4 instead of the Venturi tube. In the case of this embodiment, the in-vehicle heater 1
The coolant flowing in 2 flows in a direct path from the internal combustion engine 1 to the in-vehicle heater 12 via another thermostat valve 24.

[0029]

In summary, it becomes clear that this evaporative cooling type internal combustion engine having a cooling system capable of loading pressure has particularly good operating characteristics. System pressure and coolant temperature are
A convection cooler is attached to the condensate cooler, and the condensate from the convection cooler outlet and the condensate from the condensate cooler outlet are combined at a node in the feed pipe to the internal combustion engine, Individually adjustable by arranging a pumping device for delivering the cooling liquid in the main flow direction in the region of the nodes and preferably using a Venturi tube as the pumping device, for example as an electrically driven cooling device as the second pumping device. The liquid pump can be implemented in a compact size, a compact size, and at a low cost without causing a defect in use characteristics.

[Brief description of drawings]

FIG. 1 is a block diagram of an evaporative cooling type internal combustion engine according to the present invention, showing a state immediately after starting.

FIG. 2 is a configuration diagram of the internal combustion engine showing a state where a part of the cooling liquid is already vaporized.

FIG. 3 is a configuration diagram of an evaporative cooling type internal combustion engine similar to FIG. 1 including an in-vehicle heater.

FIG. 4 is a configuration diagram of an evaporative cooling type internal combustion engine similar to FIG. 1 including a water separator.

FIG. 5 is a configuration diagram of an evaporative cooling type internal combustion engine according to the present invention in which a compensation tank and a supply port are integrally configured.

FIG. 6 is a configuration diagram of an evaporative cooling type internal combustion engine showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Cooling system 3 ... Condensate cooler 4 ... Expansion tank 5 ... Communication pipe 11 ... Coolant pump

Claims (9)

[Claims] 1. An evaporative cooling internal combustion engine including a cooling system capable of applying a pressure and allowing a cooling liquid to flow therethrough, comprising at least one condensate cooler, at least one cooling liquid pump and one expansion tank. In which the expansion tank is connected to the cooling circuit by a connecting pipe, the expansion tank (4) is arranged immediately before the cooling liquid pump (11) in the main flow direction (9), and the condensate cooler ( A convection cooler (7) that can be input via a thermostat (6) is provided as an accessory to 3), and the cooling liquid from the convection cooler outlet and the condensate from the condensate cooler outlet are supplied to the internal combustion engine (1). The pumping devices that bring together the cooling water in the main flow direction (9) are arranged in the nodal point range, and the condensate cooler outlet and the pumping device are connected in the main flow direction (9). A pressure regulating valve (10) is arranged between Internal combustion engine. 2. Internal combustion according to claim 1, characterized in that the pumping device is formed by a Venturi tube (8) and is capable of supplying condensate in the region of the narrowest flow passage cross section in the Venturi tube (8). organ. 3. Internal combustion engine according to claim 2, characterized in that the venturi pipe (8) is formed by a T-shaped pipe connecting element. 4. An expansion tank (4) and a supply port (15) having a ventilation part are integrated into one structural unit and are fixed to each other in a liquid-conducting manner via a connecting pipe (21). The internal combustion engine according to any one of claims 1 to 3, which is characterized in that. 5. A throttle (22) is arranged in the connecting pipe (21), which throttle restricts the passage of liquid from the supply port (15) in the direction of the expansion tank (4). Item 4. The internal combustion engine according to item 4. 6. An expansion tank (4) is partitioned by a separation diaphragm (23) into a cooling liquid containing chamber (16) and an expansion chamber,
The expansion chamber communicates with the atmosphere through the ventilation hole, and the separation diaphragm (23)
6. The internal combustion engine according to claim 1, wherein the engine can be loaded only by the atmospheric pressure. 7. Separating diaphragm (23) is capable of contacting the bottom dead center of the expansion tank (4) with the cooling liquid during injection into the cooling system (2). Internal combustion engine described. 8. An in-vehicle heater (12) in the cooling system (2).
8. The in-vehicle heater is arranged in a zone of the cooling system (2) in which only the steam is filled while the internal combustion engine is used as stipulated, according to one of claims 1 to 7. Internal combustion engine. 9. A cylinder head (2) for a cooling fluid of an internal combustion engine.
Internal combustion engine according to one of the preceding claims, characterized in that it can be supplied in the range 4) and the internal combustion engine is configured as a separator.