JP2008019771A - Fuel cooling system in internal combustion engine having accumulator fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cooling device in an internal combustion engine having an accumulator fuel injection device, which efficiently utilizes temperature characteristics of oil and water existing in an engine, and effectively reduces fuel temperature by a simple structural change. <P>SOLUTION: In the internal combustion engine having the accumulator fuel injection device provided with an injector 2, an oil cooling means 8 catching lubricating oil dispersed from a camshaft, introducing it to a pipe 41, and cooling fuel by the lubricating oil, or a water cooling means 9 cooling fuel with the pipe 41 arranged in a channel built into the internal combustion engine, is provided to the pipe 41 connected to the outlet part of the injector 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cooling device in an internal combustion engine such as a diesel engine having an accumulator fuel injection device.

  In recent years, in an internal combustion engine such as a diesel engine that employs a common rail type fuel injection device (accumulation type fuel injection device), the fuel temperature has increased significantly due to the high pressure of the fuel. There is a problem that the sliding parts in the pump do not have heat.

  As a countermeasure for this, a fuel cooler is provided in the fuel piping system to reduce the fuel temperature by air cooling. However, it is costly and securing a necessary installation space is becoming increasingly difficult. In addition, the current cooling capacity is limited to the current increase in fuel temperature and tends to further increase the fuel pressure in the future. Therefore, it is difficult to cope with the current air cooling system.

Therefore, as a countermeasure for that, conventionally, a heat pipe is used to remove heat from the fuel, and this heat is transmitted to a low temperature part near the air conditioner evaporator to dissipate the heat (for example, see Patent Document 1) or a supply pump. A method of reducing heat generation from the solenoid coil of the intake metering valve (see, for example, Patent Document 2) has been proposed.
Japanese Utility Model Publication No.59-62260 JP 2003-206790 A

  However, in the conventional system, the former heat pipe is used to remove heat from the fuel and dissipate heat at a low-temperature portion near the air conditioner evaporator, so that the structure required for cooling becomes complicated and the cost increases. There was a problem.

  In the latter method of reducing the heat generation from the solenoid coil, the heat generation from the solenoid coil is only one of many factors that increase the fuel temperature, and this alone is intended to reduce the fuel temperature. A sufficient effect cannot be obtained.

  The present invention has been made in view of the above problems, and its object is to effectively utilize the temperature characteristics of oil and water present in the engine, and to effectively reduce the fuel temperature by a simple structural change. An object of the present invention is to provide a fuel cooling device for an internal combustion engine having an accumulator fuel injection device that can be reduced.

  In order to achieve the above object, a fuel cooling device for an internal combustion engine having an accumulator fuel injection device according to the present invention is connected to an outlet of the injector in an internal combustion engine having an accumulator fuel injector having an injector. The piping is provided with oil cooling means that captures the lubricating oil scattered from the camshaft, guides it to the piping, and cools the fuel with this lubricating oil. Thus, the camshaft is cooled by the oil cooling means. It is possible to cool the fuel by effectively utilizing the lubricating oil scattered from the fuel.

  Moreover, it is preferable that the oil cooling means is provided with a tray member that stores lubricating oil and immerses the pipe in the lubricating oil.

  Furthermore, the cooling efficiency of the fuel can be further improved by providing the oil cooling means and the existing air cooling means.

  According to the present invention, there is provided a fuel cooling device for an internal combustion engine having an accumulator type fuel injection device. In the internal combustion engine having an accumulator type fuel injection device having an injector, the pipe connected to the outlet portion of the injector is connected to the internal combustion engine. It is characterized in that a water cooling means for cooling the fuel is provided by being arranged in a water channel incorporated in the engine. Thus, the fuel can be cooled by effectively utilizing the existing water channel by the cooling means.

  Moreover, it is preferable to comprise piping by the thin tube divided | segmented into multiple pieces.

  Furthermore, the cooling efficiency of the fuel can be further enhanced by providing the water cooling means and the existing air cooling means.

  According to the present invention, the fuel can be efficiently cooled by effectively utilizing the existing lubricating oil and water channel by a simple change. In addition, since the heat exchange is performed with the pipe connected to the outlet of the injector, the cooling efficiency of the fuel can be maximized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of an accumulator fuel injection device provided in an internal combustion engine such as a diesel engine, which is a premise for explaining the present invention.

  This pressure accumulation type fuel injection device includes, for example, a common rail 1 for accumulating high-pressure fuel corresponding to a fuel injection pressure supplied to each cylinder of a multi-cylinder diesel engine, a plurality of injectors 2 mounted for each cylinder, and a later-described And a supply pump 3 that pressurizes the fuel from the fuel tank 5 and feeds it to the common rail 2.

  Each injector 2 (only one is shown in FIG. 1) is connected to the downstream end of a plurality of branch pipes 1a branched from the common rail 1, and the high pressure fuel accumulated in the common rail 1 according to the opening and closing of the electromagnetic valve. Is injected and supplied to each cylinder.

  The leaked fuel from the injector 2 is returned to the fuel tank 5 from the leak pipe 41 connected to the outlet thereof, and the leaked fuel from the supply pump 3 is returned from the leak pipe 42 to the fuel tank 5 through the return pipe 4. The return pipe 4 is provided with a conventionally known air-cooled fuel cooler 6 for cooling the fuel returned to the fuel tank 5. Further, a filter 7 is provided in a pipe that leads from the fuel tank 5 to the supply pump 3.

  The pressure-accumulation fuel injection apparatus configured as described above is provided with an oil cooling means 8 that constitutes a main part of the present invention. Hereinafter, a specific configuration of the oil cooling means 8 will be described with reference to FIGS. This will be described with reference to FIG.

  The oil cooling means 8 is for cooling the fuel that becomes high temperature as the pressure of the fuel is increased by the pressure accumulating fuel injection device, and includes a guide member 81.

  The guide member 81 is provided above the leak pipe 41 that introduces leak fuel from each injector 2 to the fuel tank 5 through the return pipe 4. Specifically, the guide member 81 has a predetermined length in which the cross-sectional shape is formed in an arch shape whose diameter is sufficiently larger than the leak pipe 41, and the guide member 81 includes a plurality of connecting members. It is connected to the leak pipe 41 through 82.

  As a result, the lubricating oil scattered around the camshaft Cs can be captured by the guide member 81 and guided to the leak pipe 41. That is, the lubricating oil that has fallen on the upper surface of the guide member 81 and the lubricating oil that has hit the lower surface of the guide member 81 are guided from the guide member 81 to the outer peripheral surface of the leak pipe 41 through the connecting member 82. The fuel temperature is lowered by exchanging heat with the fuel in 41.

  By simply changing the guide member 81 above the leak pipe 41 in this way, conventionally, lubricating oil that has only been scattered around the camshaft Cs can be guided to the leak pipe 41 through the guide member 81. Thus, the fuel can be efficiently cooled by effectively utilizing the scattering of the lubricating oil. In addition, since the heat exchange is performed with the leak pipe 41 having the highest fuel temperature immediately after the injector relief, the cooling efficiency of the fuel can be maximized.

  The fuel can be further effectively cooled by providing the above-described oil cooling means 8 together with the air cooling means by the fuel cooler 6 shown in FIG.

  FIG. 4 shows only the air cooling means with respect to the temperature change of the fuel in each part (refer to the solid line) accompanying the movement of combustion in the fuel supply path shown in FIG. It is the figure compared with the same temperature change (refer broken line). It can be seen from FIG. 4 that the oil cooling means 8 is provided so that the temperature at the outlet portion (a) of the injector provided with the oil cooling means 8 is drastically reduced as compared with the case of only air cooling.

  Further, by exchanging heat with the fuel by the oil cooling means 8 in this way, as shown in FIG. 5, when starting the engine, lubrication is shown as indicated by a thick line compared to only the air cooling means indicated by a thin line. The oil temperature rises quickly, and the friction oil temperature rise can reduce the friction at each part in the engine, and accordingly, the fuel efficiency can be improved at the time of starting.

  6 and 7 show another example of the oil cooling means.

  The oil cooling means 8 is provided with a tray member 83 together with the guide member 81 described above.

  The tray member 83 has a predetermined length with a cross-sectional shape formed in a curved shape, and the leak pipe 41 is placed below the guide pipe 81 and the leak pipe 41 that is the target position with the leak pipe 41 interposed therebetween. It is arranged in a wrapping form. In this case, the tray member 83 is connected to the leak pipe 41 by a plurality of connecting members 84, and the guide member 81 is connected to the tray member 83 by the connecting member 82.

  By providing the tray member 83 in this manner, the lubricating oil splashed from the camshaft Cs is directly received by the tray member 83, and the lubricating oil captured by the guide member 81 is also introduced into the tray member 83, thereby the tray member. In 83, lubricating oil is stored.

  As a result, by immersing the leak pipe 41 in the lubricating oil accumulated in the tray member 83 as described above, the leak pipe 41 comes into direct contact with the lubricating oil. In this state, the fuel in the leak pipe 41 and the lubricating oil are lubricated. Heat exchange is performed with oil.

  For this reason, the heat transfer rate is remarkably increased as compared with the case where only the lubricating oil scattered by the guide member 81 described above is applied, thereby further improving the cooling efficiency of the fuel.

  The saucer member 83 is arranged in a slightly inclined state in the longitudinal direction so that the lubricating oil accumulated in the saucer member 83 flows out sequentially, whereby the lubricating oil is retained by the stay in the saucer member 83. The temperature rise is suppressed.

  8 and 9 show a modification of the guide member constituting the oil cooling means.

  In this guide member, a plurality of circular fins 85, for example, are arranged around the leak pipe 41 at a predetermined interval, and the lubricating oil scattered from the camshaft is captured by the fins 85 in the same manner as described above to leak. The fuel is guided to the pipe 41, so that the fuel is cooled in the same manner as described above.

  Thus, the same effect as the guide member 81 mentioned above can be acquired also by comprising a guide member with the several fin 85. FIG. Further, in the case of using the fins 85, a high heat radiation effect by the fins 85 from the leak pipe 41 can be expected.

  10 and 11 show another modification of the guide member constituting the oil cooling means.

  In this guide member, a mesh 86 is arranged in a cylindrical shape on the outer periphery of the leak pipe 41. In this case, the lubricant is captured by the action of the mesh 86 itself and guided to the leak pipe 41 to cool the fuel. be able to.

  Thus, by configuring the guide member with the mesh 86, the same effect as the above-described guide member 81 can be obtained.

  12 and 13 show a configuration in which the water cooling means 9 is arranged in the leak pipe 41 instead of the oil cooling means described above.

  The water cooling means 9 cools the fuel by exchanging heat with the fuel using a water passage built in the engine. Specifically, for example, the leak pipe 41 is constituted by a thin pipe 41 a divided into a plurality of pipes, and the thin pipe 41 a is inserted into the water channel 91.

  As a result, the flow rate of the fuel can be sufficiently secured by the plurality of thin tubes 41a, and a large surface area in contact with the water in the water channel 91 can be secured, so that the heat exchange rate between the two can be sufficiently increased. .

  Thus, the fuel can be efficiently cooled by exchanging heat with the fuel by a simple change using the existing water channel incorporated in the engine. In addition, since the heat exchange is performed at the leak pipe 41 where the fuel temperature immediately after the injector relief is highest, the cooling efficiency of the fuel can be maximized.

  As the water channel 91, for example, the inlet side of the heater water channel may be used, or the inlet side of the ATF warm water channel is preferably used. Further, as shown in FIG. 14, the leak pipe 41 may be disposed in the water passages 92, 93 using the water passages 92, 93 incorporated in the engine head E <b> 1 and the cylinder block E <b> 2. In FIG. 14, symbol E3 is a head cover, and Cy is a cylinder.

  Then, the water cooling means 9 described above is provided together with the air cooling means by the fuel cooler 6 shown in FIG.

  FIG. 15 shows the temperature change of the fuel at each part (refer to the solid line) in each part accompanying the movement of combustion in the fuel supply path shown in FIG. 1 when the water cooling means 9 and the air cooling means are provided together. It is the figure compared with the various temperature change (refer broken line). It can be seen from FIG. 15 that the provision of the water cooling means 9 significantly reduces the temperature at the outlet (a) of the injector provided with the water cooling means 9 as compared with the case of only air cooling.

  Further, when such a water cooling means is provided, for example, on the inlet side of the heater water channel and heat is exchanged with fuel, as shown in FIG. As shown by the thick line, the temperature of the heater water temperature rises quickly, and this temperature rise can contribute to the early rise of the heater performance.

  Note that the fuel can be cooled by the original cooling action that acts on the engine even if the leak pipe 41 is disposed in the head E1 or the cylinder block E2 shown in FIG. 14 without passing through the water passage in the engine.

It is a figure which shows schematic structure of the pressure accumulation type fuel-injection apparatus provided in internal combustion engines, such as a diesel engine. It is a perspective view which shows an oil cooling means. It is a longitudinal cross-sectional view which similarly shows this oil cooling means. It is a figure which shows the temperature change of the fuel in each site | part of a fuel supply path in the case where an oil cooling means and an air cooling means are provided side by side. It is a figure which shows the temperature change of the lubricating oil at the time of engine starting. It is a perspective view which shows the other example of an oil cooling means. It is a longitudinal cross-sectional view which similarly shows this oil cooling means. It is a perspective view which shows the other example of an oil cooling means. It is a longitudinal cross-sectional view which similarly shows this oil cooling means. It is a perspective view which shows the other example of an oil cooling means. It is a longitudinal cross-sectional view which similarly shows this oil cooling means. It is a perspective view which shows a water cooling means. It is a longitudinal cross-sectional view which similarly shows this water cooling means. It is a schematic sectional drawing which shows the other example of a water cooling means. It is a figure which shows the temperature change of the fuel in each site | part of a fuel supply path | route in the case where a water cooling means and an air cooling means are provided side by side. It is a figure which shows the temperature change of the heater water temperature at the time of engine starting.

Explanation of symbols

2 Injector 4 Return pipe 41 Leak pipe 8 Oil cooling means 9 Air cooling means Cs Camshaft

Claims (6)

In an internal combustion engine having a pressure accumulation type fuel injection device provided with an injector,
The piping connected to the outlet portion of the injector is provided with an oil cooling means for capturing lubricating oil scattered from the camshaft and guiding it to the piping, and cooling the fuel with the lubricating oil. Cooling device for an internal combustion engine having a fuel injection device.   2. The internal combustion engine having a pressure accumulating fuel injection device according to claim 1, wherein the oil cooling means is provided with a tray member that stores lubricating oil and immerses the piping in the lubricating oil. Fuel cooling device.   3. The fuel cooling apparatus for an internal combustion engine having an accumulator fuel injection apparatus according to claim 1, wherein the oil cooling means and an existing air cooling means are provided side by side. In an internal combustion engine having a pressure accumulation type fuel injection device provided with an injector,
The piping connected to the outlet of the injector has a pressure-accumulating fuel injection device provided with water cooling means for cooling the fuel by disposing the piping in a water passage incorporated in the internal combustion engine. A fuel cooling device for an internal combustion engine.   5. The fuel cooling device for an internal combustion engine having a pressure accumulating fuel injection device according to claim 4, wherein the pipe is constituted by a thin tube divided into a plurality of pipes.   6. The fuel cooling apparatus for an internal combustion engine having a pressure accumulating fuel injection apparatus according to claim 4, wherein the water cooling means and an existing air cooling means are provided side by side.

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