JP2007231803A - Cylinder lubricating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder lubricating device capable of providing good lubricating performance in a cylinder of an engine, especially a diesel engine using fuel as lubricating oil. <P>SOLUTION: The cylinder lubrication device 20 is provided with a high pressure fuel injection valve 19 injecting fuel into the cylinder 21 of the engine 1 at high pressure, and a low pressure fuel injection valve 24 injecting fuel into the cylinder at low pressure. The low pressure fuel injection valve 24 is supplied with fuel by a lubrication pump supplying fuel as lubricating oil to an engine lubrication system such as a periphery of a cylinder head and a periphery of a crankshaft. Injected fuel can be adhered on a cylinder liner 22 without evaporating the same by injecting fuel into the cylinder 21 at low pressure. Consequently, fuel evaporates on the cylinder liner 22 to avoid getting into a dry condition to reduce friction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cylinder lubricating device that supplies lubricating oil to a cylinder liner of an engine.

  2. Description of the Related Art Conventionally, a cylinder lubrication device that injects cylinder oil into a cylinder liner sliding surface of a large marine diesel engine has been proposed (Patent Document 1). In Patent Document 1, a plunger piston that is driven by fuel oil discharged from a fuel injection pump is provided, and by reciprocation of the plunger piston, cylinder oil is supplied near the top dead center of the piston substantially in synchronization with the fuel injection timing. Is disclosed, and a sufficient amount of cylinder oil is supplied to the sliding surface of the cylinder liner in the vicinity of the top dead center of the piston. The cylinder oil is injected from the oil filling port by driving the plunger with a fuel cam linked to the crankshaft of the engine.

  Further, Patent Document 2 discloses an internal combustion engine lubrication device that neutralizes a sulfuric acid component generated during combustion by spraying basic oil on the cylinder liner upper peripheral portion to reduce corrosion and wear of the cylinder liner and piston ring. Has been proposed.

  Moreover, a light oil lubricated diesel engine that uses light oil as a fuel as a lubricating oil is disclosed (Patent Document 3). In such a light oil lubricated diesel engine, light oil as a fuel is also used as a lubricant for each part of the engine and circulates through each part of the engine. For this reason, the oil only for lubrication is unnecessary, and the effort of oil replacement can also be saved.

JP 7-42522 A Japanese Utility Model Publication No. 4-57609 Japanese Utility Model Publication No. 60-194112

  The cylinder lubrication device disclosed in Patent Document 1 branches fuel discharged from a fuel injection pump that supplies high-pressure fuel to a fuel injection valve for combustion in a cylinder to a plunger piston, and the plunger piston reciprocates. The cylinder oil is supplied to the oil inlet by the movement. That is, the plunger piston is driven using the fuel whose pressure is increased by the fuel injection pump, and the cylinder oil for lubrication is supplied to the cylinder liner.

  For this reason, such a cylinder lubrication device disclosed in Patent Document 1 cannot be mounted in a form as it is on a diesel engine in which the fuel as disclosed in Patent Document 3 also serves as a lubricating oil.

  Moreover, in the diesel engine as disclosed in Patent Document 3, the following problems may occur. In such a diesel engine, light oil is generally used as a fuel, and light oil is supplied to a lubrication system to contribute to lubrication of each part. However, since light oil evaporates more easily than general engine oil, under severe conditions for the engine, such as during high-load high-speed operation of the engine, the light oil in the cylinder liner evaporates into a dry state, causing abnormal wear, There is a risk of damage to the engine, such as seizure of the piston.

  In addition, the lubrication device for an internal combustion engine described in Patent Document 2 aims to reduce the corrosion and wear of the cylinder liner and the piston ring by neutralizing the sulfuric acid component generated during combustion. It is not configured to supply lubricating oil to the cylinder liner for the purpose of reducing and preventing seizure. Therefore, even if such a lubricating device for an internal combustion engine is mounted on an engine as disclosed in Patent Document 3, it does not lead to avoiding the dry state of the engine.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cylinder lubrication device capable of obtaining good lubrication performance in an engine, in particular, a cylinder of a diesel engine that uses both fuel and lubricating oil.

  In order to solve this problem, a cylinder lubrication apparatus according to the present invention includes a high-pressure fuel injection valve that injects fuel at high pressure into a cylinder of an engine that uses fuel as lubricating oil, and low-pressure fuel for cylinder liner lubrication of the cylinder. And a low-pressure fuel injection valve that injects at (1). Here, the high-pressure fuel injection valve is similar to that provided in a conventional engine, and injects fuel to be used for combustion in a cylinder. For this reason, fuel is sprayed from the high-pressure fuel injection valve, and fuel is injected at a pressure that is easy to vaporize. On the other hand, the low pressure fuel injection valve is for injecting fuel in order to obtain good lubrication characteristics in the cylinder liner. That is, the low-pressure fuel injection valve is a valve for injecting fuel into the cylinder in order to use the fuel as lubricating oil. For this reason, the injection pressure of the low-pressure fuel injection valve is adjusted to a pressure at which the fuel is difficult to vaporize so that the function as the lubricating oil is easily exhibited. Naturally, this pressure is lower than the fuel injection pressure in the high-pressure fuel injection valve.

  Such a low-pressure fuel injection valve is preferably configured to inject fuel toward the cylinder liner. This is because the injected fuel is attached to the cylinder liner before vaporizing or burning in the cylinder, and the injected fuel functions as a lubricating oil.

  When the fuel is used as the engine lubricating oil, the cylinder lubricating device of the present invention can be configured as follows. That is, the engine includes, for example, a fuel tank and an oil tank that stores fuel sent from the fuel tank and supplies fuel to a fuel injection system and an engine lubrication system. The low-pressure fuel injection valve may be configured to be supplied with fuel by a lubrication pump that supplies fuel to the engine lubrication system. Here, the fuel injection system may include a fuel injection pump for supplying fuel at a high pressure and a common rail, and high-pressure fuel is injected from the high-pressure fuel injection valve through such a fuel injection system. On the other hand, the engine lubrication system includes parts of the engine that need to be supplied with lubricating oil, for example, around the crankshaft and the cylinder head, and the fuel used as the lubricating oil in such an engine lubricating system. Is supplied by a lubrication pump. The pressure at which the lubrication pump pumps the fuel is such that the fuel can be distributed to the engine lubrication system. Accordingly, the pressure is low even when compared with the pressure at which the fuel injection pump pumps the fuel. Therefore, the fuel can be pumped using such a low-pressure lubrication pump, and fuel as lubricating oil can be injected from the low-pressure fuel injection valve.

  The fuel can be supplied to the low-pressure fuel injection valve by a low-pressure fuel pump incorporated in a fuel injection pump that supplies fuel to the fuel injection system. As described above, the fuel injection system may include a fuel injection pump that supplies fuel at a high pressure and a common rail, and high-pressure fuel is injected from the high-pressure fuel injection valve through such a fuel injection system. Here, the fuel injection pump includes a combination of a low pressure fuel pump and a high pressure fuel pump. That is, there is a configuration in which boosting is performed in two stages in order to increase the pressure of the fuel up to the pressure at the time of injection from the high-pressure fuel injection valve. The fuel can be divided from between the low-pressure fuel pump and the high-pressure fuel pump constituting such a fuel pump, and the divided fuel can be injected as lubricating oil from the low-pressure fuel injection valve.

  Moreover, the cylinder lubricating device of this invention can be set as the following structures. That is, the engine includes a fuel tank and an oil tank that stores fuel sent from the fuel tank and supplies fuel to a fuel injection system and an engine lubrication system. The fuel in the fuel tank can be supplied (claim 4). Here, the oil tank performs the same or similar function as an oil pan mounted on a general engine. A fuel tank generally has a larger capacity and a lower internal fuel temperature than such an oil tank. Therefore, if the fuel having a temperature as low as possible is discharged from the oil inlet as lubricating oil, evaporation of the lubricating oil can be avoided as much as possible. As a result, good lubrication characteristics in the cylinder liner can be maintained.

  According to the present invention, a high-pressure fuel injection valve that injects fuel at a high pressure into a cylinder of an engine that uses fuel as lubricating oil, and a low-pressure fuel injection valve that injects fuel at a low pressure toward the cylinder liner of the cylinder. Since the lubricating oil is supplied from the low-pressure fuel injection valve, the lubricating oil injected from the low-pressure fuel injection valve is difficult to vaporize, and the lubricating characteristics of the cylinder liner can be maintained.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing a schematic configuration of a cylinder lubrication device 20 of the present invention mounted on an engine 1. The engine 1 is a diesel engine that uses light oil as a fuel as a lubricating oil. FIG. 2 is an explanatory diagram showing a schematic configuration of a fuel supply portion mainly of the engine 1. First, a schematic configuration of such an engine 1 will be described. The engine 1 includes a fuel tank 2 and an oil pan 3. The fuel tank 2 and the oil pan 3 communicate with each other through a fuel supply path 4. The fuel supply path 4 is provided with a cementer 5 and an electric supply pump 6, and fuel is supplied from the fuel tank 2 to the oil pan 3 by the electric supply pump 6. Here, although the oil pan 3 refers to what was integrally provided in the lower part of the cylinder block, it may be a separately installed oil tank.

  The engine 1 has a lubricating system fuel supply path 8 for supplying fuel as lubricating oil to an engine lubricating system 7 that needs to be supplied with lubricating oil. The lubrication system fuel supply path 8 is provided with a filter 9 and a lubrication pump 10 capable of pumping fuel at a pressure of about 50 to 400 kPa. The lubrication pump 10 is driven to suck up the fuel from the oil pan 3. Supply to engine lubrication system 7. Here, the engine lubrication system 7 refers to a portion that receives supply of lubricating oil in a general engine, such as around the cylinder head or the crankshaft of the engine 1.

  Such a lubrication system fuel supply path 8 includes a branch path 30 that branches downstream of the lubrication pump 10. This branch path 30 is connected to a low-pressure fuel injection valve 24 mounted on the cylinder head 23 as shown in FIG. The low-pressure fuel injection valve 24 injects the fuel toward the cylinder liner 22 at such a pressure that the fuel is not vaporized and does not become a spray state. The fuel injected in this way adheres to the cylinder liner 22 and reduces friction with the piston 25.

  The engine 1 has a lubrication system fuel return path 11 for returning the fuel supplied to the engine lubrication system 7 through the lubrication system fuel supply path 8 to the oil pan 3.

  Furthermore, the engine 1 has an injection system fuel supply path 13 that supplies fuel to an injection system 12 that injects fuel into the cylinder. The injection system fuel supply path 13 is provided with a filter 14 and a fuel injection pump 15 capable of pumping fuel at a high pressure of 10 MPa or more. By driving the fuel injection pump 15, the fuel is sucked up from the oil pan 3. To the injection system 12. Here, the fuel injection pump 15 includes a low-pressure fuel pump 15a and a high-pressure fuel pump 15b. A common rail (not shown) is disposed downstream of the fuel injection pump 15, and a high-pressure fuel injection valve 19 as shown in FIG. 1 is connected to the common rail. As shown in FIG. 1, the high-pressure fuel injection valve 19 is mounted on the cylinder head 23 so that the tip thereof faces the inside of the cylinder 21. The high-pressure fuel injection valve 19 injects fuel at a pressure of 20 MPa or more so that it can be easily burned in the cylinder.

  The engine 1 also has an injection system fuel return path 16 that returns the injection system return fuel that has been supplied to the injection system 12 through the injection system fuel supply path 13 to the fuel tank 2. The injection system return fuel refers to return fuel returned from each of the common rail, the high pressure fuel injection valve 19 and the like (not shown).

  The electric supply pump 6 is connected to an ECU (not shown). The ECU is connected to an oil level sensor and various sensors of the engine, and the discharge amount of the electric supply pump 6 is controlled based on a command based on the engine operating condition of the engine 1 processed by the ECU. Yes.

  That is, the lubricating oil in the engine 1 uses fuel for engine operation, and various pipes are provided for this purpose.

  In the cylinder lubricating device 20 having such a configuration, fuel injected as lubricating oil from the low-pressure fuel injection valve 24 is supplied to the cylinder liner 22 separately from the fuel injected from the high-pressure fuel injection valve 19 to be burned in the cylinder 21. Adhere to. In this way, the fuel adhering to the cylinder liner 22 is less likely to evaporate and is less likely to evaporate, that is, less likely to be in a dry state, so that friction between the cylinder liner 22 and the piston 25 can be reduced.

  Next, Embodiment 2 of the present invention will be described with reference to FIG. The second embodiment differs from the first embodiment in that the first embodiment has a branch path 30 that branches from the downstream side of the lubrication pump 10, and the fuel that serves as lubricating oil through the branch path 30 to the low-pressure fuel injection valve 24. However, in the second embodiment, the branch path 31 is branched from the downstream of the low-pressure fuel pump 15a, and fuel serving as lubricating oil is supplied to the low-pressure fuel injection valve 24 through the branch path 31. It is. Another difference is that a bypass path 40 for connecting the fuel supply path 4 and the injection system fuel supply path 13 is provided. A three-way valve 41 is mounted at a connection point between the bypass path 40 and the injection system fuel supply path 13.

  Even with such a configuration, the same effects as those of the first embodiment can be obtained. However, the fuel from the fuel tank 2 can be injected from the low-pressure fuel injection valve 24 by switching the three-way valve 41 based on a command from an ECU (not shown) according to the operating state of the engine 1.

  The fuel tank 2 may have a larger capacity than the oil tank 3, and the fuel in the fuel tank 2 is considered to have a lower temperature than the fuel in the oil tank 3. Better lubrication characteristics can be maintained by injecting fuel from the low-pressure fuel injection valve 24 that is low in temperature and difficult to evaporate.

  The other constituent elements are the same as those in the first embodiment. The same constituent elements are denoted by the same reference numerals in the drawings, and detailed description thereof is omitted.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

It is a schematic diagram which shows schematic structure of the cylinder lubrication apparatus of Example 1. FIG. It is explanatory drawing which showed schematic structure of the fuel supply part mainly of the engine of Example 1. FIG. It is explanatory drawing which showed schematic structure of the fuel supply part mainly of the engine of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 19 High pressure fuel injection valve 20 Cylinder lubrication device 21 Cylinder 22 Cylinder liner 23 Cylinder head 24 Low pressure fuel injection valve 25 Piston

Claims (4)

A high-pressure fuel injection valve that injects fuel at a high pressure into a cylinder of an engine that uses fuel as lubricating oil;
A low pressure fuel injection valve for injecting fuel for lubricating the cylinder liner of the cylinder at a low pressure;
A cylinder lubrication device comprising: The cylinder lubrication device according to claim 1, wherein
The engine includes an engine lubrication system,
A cylinder lubrication device characterized in that fuel is supplied to the low-pressure fuel injection valve by a lubrication pump that supplies fuel to the engine lubrication system. The cylinder lubrication device according to claim 1, wherein
The engine includes a fuel injection system,
A cylinder lubrication device characterized in that fuel is supplied to the low-pressure fuel injection valve by a low-pressure fuel pump incorporated in a fuel injection pump that supplies fuel to the fuel injection system. The cylinder lubrication device according to claim 1, wherein
The engine includes a fuel tank,
An oil tank for storing fuel sent from the fuel tank and supplying fuel to a fuel injection system and an engine lubrication system;
A cylinder lubrication apparatus characterized in that fuel in the fuel tank is supplied to the low-pressure fuel injection valve.

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