JP2010190044A - Dilution prevention device for engine lubricating oil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent dilution and degradation of lubricating oil of a whole lubricating system by collecting lubricating oil supplied to a sliding surface of a cylinder separately from lubricating oil supplied to an engine and other parts. <P>SOLUTION: A partition plate 14 having a through hole pierced by a connecting rod 3 and moving according to rocking motion of the connecting rod 3 is arranged below the cylinder 1. The partition plate 14 moves side to side by a cam 18 driven by a crank shaft 4 and prevents diluted lubricating oil scraped from the sliding surface of the cylinder 1 and diluted by a fuel from dropping on an oil pan 13. As the diluted lubricating oil on the partition plate 14 is collected from a diluted oil receiver 19 by a diluted lubricating oil collection device 20 and does not mix into the oil pan 13, the lubricating oil of the whole lubricating system is free from dilution and degradation. In the diluted lubricating oil collection device 20, the fuel and the lubricating oil are separated and the fuel is utilized as an additional fuel for a NOx storage reduction catalyst 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an engine lubricating oil dilution prevention device for preventing lubricating oil supplied to a rotating portion and a sliding portion of an engine from being diluted by mixing of fuel supplied into an engine cylinder. is there.

  A gasoline engine or a diesel engine mounted on a vehicle or the like includes a piston that reciprocates in a cylinder, and the piston is connected to a crankshaft by a connecting rod. In addition, these engines are equipped with a lubrication system that supplies lubricating oil to the rotating part and the sliding part. In the lubricating system, the oil is stored in an oil pan mounted below the cylinder block of the engine. A tank is provided, and this lubricating oil is pumped by an oil pump to a crankshaft or connecting rod bearing, a sliding portion of a cam that drives an intake / exhaust valve, and the like. After lubricating these portions, the lubricating oil falls into the oil tank and circulates again to the oil pump.

  A piston ring is fitted on the outer periphery of the piston, and the piston reciprocates in the cylinder while the piston ring slides on the inner surface of the cylinder. As shown in FIG. 5, a part of the lubricating oil pumped from the oil pump is injected from the nozzle provided at the top of the connecting rod toward the back surface of the piston to cool the piston, and between the piston ring and the cylinder. The oil film of lubricating oil is also formed on the cylinder sliding surface. This oil film greatly reduces the sliding frictional resistance between the piston ring and the cylinder, and at the same time contributes to the sealing of combustion gas and the like above the piston.

  By the way, fuel is supplied into the cylinder, and combustion is performed in the combustion stroke from the end of the compression stroke. For example, in a diesel engine, fuel is injected into a cylinder from a fuel injection valve attached to the cylinder head at the end of the compression stroke, but the lubricant on the cylinder sliding surface may be diluted by mixing of the injected fuel. is there. When the lubricating oil is diluted, the viscosity decreases and it becomes impossible to maintain an appropriate oil film, so the sliding friction resistance increases and the fuel consumption of the engine deteriorates. Cause damage. Further, the diluted lubricating oil falls to the oil pan and lowers the viscosity of the lubricating oil in the entire lubricating system.

In recent years, there has been a strong demand for reduction of nitrogen oxides (NOx) and particulate matter (particulates: PM) contained in exhaust gas of diesel engines. An exhaust gas aftertreatment device using a NOx occlusion reduction catalyst is known as a means for removing NOx from exhaust gas. In this device, NOx in the exhaust gas is occluded in the catalyst when the exhaust gas atmosphere is excessive in oxygen. Then, the reducing atmosphere gas (spike gas) is intermittently passed through the catalyst to reduce and remove NOx. To make the exhaust gas into a reducing atmosphere gas, a method of adding fuel in the exhaust pipe and combining it with the remaining oxygen, or a method called so-called post-injection in which the added fuel is injected into the cylinder at the end of the combustion stroke of the engine However, when post injection is performed, the lubricant on the cylinder sliding surface is more diluted.
Incidentally, the addition of fuel by this post injection or the like is a so-called DPF that burns and removes PM accumulated in the DPF in a diesel engine equipped with a diesel particulate filter (DPF) that collects PM in the exhaust gas. During the regeneration, the exhaust gas may be heated to raise the temperature.

In order to prevent the dilution of the lubricating oil, an engine having a device for separating and removing fuel mixed in the lubricating oil is known. For example, it is disclosed in Japanese Patent Application Laid-Open No. 2002-266619 related to the prior application of the present applicant. ing. The diesel engine of this publication is of a sub-combustion chamber type, and as shown in FIG. 6A, a sub-combustion chamber type 103 communicates with a cylinder 102 in which a piston 101 reciprocates. Fuel is injected from the injection valve 104. An oil pan 107 that forms an oil tank for lubricating oil is attached to the lower part of the crankcase 106 that accommodates the crankshaft 105, and the lubricating oil in the oil tank is pumped up by the oil pump 108, and the crankshaft 105 and the like. Supplied to the rotating part and the sliding part.
Lubricating oil supplied to the rotating portion or the like is collected in the oil pan 107, but the lubricating oil supplied to the sliding surface of the cylinder 102 also falls to the oil pan 107 in a state where fuel is mixed. This engine is equipped with a separation device 109 shown in detail in FIG. 6 (b), and the mixture of the lubricating oil and fuel that falls is separated into a separation container 112 in which an electric heater 111 is installed via a pipe 110. It is sent. In the separation vessel 112, the temperature control of the electric heater 111 is executed so that only the fuel evaporates due to the difference in distillation temperature. As a result, the fuel is separated from the lubricating oil, the fuel is cooled by the condenser 113 and collected in a fuel tank or the like, and the lubricating oil is returned to the oil pan 107 by the pump 114.

JP 2002-266619 A

  In an engine lubrication system, lubricating oil is supplied to each part such as a rotating part and a sliding part, and the lubricating oil after lubricating each part is collected in an oil tank of an oil pan. However, it is the lubricating oil that is mainly supplied to the sliding surface of the cylinder that is diluted by the fuel, and the lubricating oil for the bearing portion of the crankshaft or the valve gear is not diluted by the fuel. . Since the amount of lubricating oil supplied to the sliding surface of the cylinder is relatively small from the whole lubrication system, it is the content (concentration) that separates the fuel for the entire lubricating oil that returns to the oil pan. ) Is reduced, and efficient separation is difficult.

Further, the lubricating oil supplied to the sliding surface of the cylinder is severely deteriorated due to changes in properties due to the influence of combustion heat, mixing of unburned fuel components such as soot. When the lubricating oil that has been diluted or deteriorated by the fuel falls into the oil pan that has fallen from the cylinder wall into the oil pan, the lubricating oil in the entire lubricating system is prematurely deteriorated.
The present invention collects lubricating oil supplied to the sliding surface of the cylinder separately from the lubricating oil supplied to the other parts of the engine, and prevents dilution and deterioration of the lubricating oil in the entire lubrication system. At the same time, it is an object to efficiently separate fuel and the like.

In view of the above problems, the present invention has a through-hole through which the connecting rod penetrates, and a partition plate that moves in accordance with the swing of the connecting rod is installed below the cylinder so that the lubricating oil diluted with fuel is A diluted lubricating oil recovery device is provided that prevents the lubricant from falling from the sliding surface of the cylinder to the oil tank and collects this lubricating oil separately. That is, the present invention
“An engine having a piston that reciprocates inside a cylinder, the piston being connected to a crankshaft by a connecting rod,
The engine includes an oil pump that pumps lubricating oil and an oil tank that is installed below the crankshaft and collects and stores the lubricating oil, and a part of the lubricating oil is transferred from the oil pump to the cylinder. Configured to be supplied, and
Between the cylinder and the crankshaft, there is provided a partition plate that has a through hole through which the connecting rod penetrates and moves according to the swinging of the connecting rod, and lubrication that falls from the cylinder to the partition plate. Diluted lubricating oil recovery device is provided to recover oil. ''
The engine is characterized by that.

  According to a second aspect of the present invention, a partition wall can be formed between the cylinder and the crankshaft so that the partition plate moves on the partition wall.

  According to a third aspect of the present invention, it is preferable that a separation device for separating the lubricating oil and the fuel is installed in the diluted lubricating oil recovery device so that the separated lubricating oil is returned to the oil tank. The separating device in this case can be provided with rotating blades as described in claim 4. Further, when the engine is a diesel engine having an added fuel supply device in an exhaust pipe, the separated fuel can be supplied to the exhaust pipe as an added fuel as described in claim 5.

  Gasoline engines and diesel engines, which are so-called reciprocating engines, have a piston that reciprocates inside the cylinder. The piston is connected to the crankshaft by a connecting rod, and the sliding surface of the cylinder is lubricated from an oil pump. Part of the oil is supplied. In the engine of the present invention, a partition plate is installed between the cylinder and the crankshaft. The partition plate has a through-hole through which the connecting rod passes and is configured to move in accordance with the swing of the connecting rod. Therefore, the lubricating oil diluted with the fuel that falls from the cylinder is blocked by the partition plate and accumulated above, and does not fall down to the oil pan and be mixed into the lubricating oil in the oil tank. The lubricating oil collected above the partition plate is separately collected from the diluted lubricating oil collecting device.

  Thus, since the lubricating oil returned from the cylinder is not mixed with the lubricating oil in the oil tank, the lubricating oil supplied to parts other than the cylinder, such as the bearing portion of the crankshaft, is diluted with fuel or is an unburned component. It is possible to prevent the viscosity from being lowered or causing premature deterioration due to mixing of certain soot and the like. Lubricating oil with a high content such as fuel recovered in the diluted lubricating oil recovery device is purified by a separation device as will be described later, but in some cases, it is stored in a dedicated tank and the engine is stopped, etc. It may be cleaned regularly with dedicated equipment.

  The invention of claim 2 is configured such that a partition wall is formed between the cylinder and the crankshaft, and the partition plate through which the connecting rod penetrates slides on the partition wall in accordance with the swing of the connecting rod. It is. According to this, between the cylinder and the oil tank is completely divided by the partition wall and the partition plate, it is possible to reliably prevent the lubricating oil from the cylinder from falling into the oil tank.

According to a third aspect of the present invention, a separator for separating the lubricating oil and the fuel is installed in the diluted lubricating oil recovery device, and the lubricating oil is extracted and separated from the lubricating oil having a high content such as fuel, and this is separated into the engine oil. It is returned to the tank and circulated. The lubricating oil recovered by the diluted lubricating oil recovery apparatus of the present invention is a small amount from the entire lubrication system. In the invention of claim 3, a small amount of lubricating oil having a high fuel concentration is processed. The fuel can be efficiently removed by the separation device.
As the apparatus for separating the lubricating oil and the fuel, an apparatus for separating by the difference in viscosity provided with rotating blades can be used. However, it is also possible to employ another type of separation device such as a separation device that uses the difference in evaporation temperature disclosed in Patent Document 1.

  The invention of claim 5 applies the invention of claim 3 to a diesel engine in which an additive fuel supply device is installed in an exhaust pipe in order to supply additive fuel to a NOx storage reduction catalyst or DPF which is an exhaust gas aftertreatment device, The fuel separated from the lubricating oil by the separator is supplied as an additional fuel to the exhaust pipe. The so-called main fuel supplied to the cylinder of a diesel engine is injected by a precise high-pressure fuel injection device. If soot or lubricating oil is mixed in this fuel, the injection device may be damaged. There is. On the other hand, the additive fuel supply device to the exhaust pipe in the invention of claim 5 is a relatively low pressure fuel injection device, and is hardly adversely affected even if soot and lubricating oil are slightly mixed. Moreover, these will burn and disappear in exhaust gas.

It is the schematic which shows one Example of the partition plate for dilution lubricant fall prevention of this invention. It is a principal part enlarged view of FIG. It is a figure which shows the modification of the partition plate for dilution lubricant fall prevention of this invention. It is the schematic which shows one Example of the separation apparatus of this invention. It is a figure which shows the general lubricating oil supply apparatus to a cylinder sliding surface and a piston. It is the schematic of the conventional engine provided with the separation apparatus of lubricating oil and fuel.

  The present invention will be described below with reference to the drawings. FIG. 1 schematically shows an overall view of an embodiment in which the present invention is applied to a diesel engine equipped with a NOx occlusion reduction catalyst, and FIG. 2 shows a partition plate for preventing the fall of diluted lubricating oil in FIG. The part is shown in an enlarged manner. However, FIG. 1 shows a state in which the connecting rod is inclined with respect to the cylinder axis, whereas in FIG. 2, the connecting rod coincides with the cylinder axis (the piston is located at the top dead center or the bottom dead center). Is shown. FIG. 3 shows a modification of the partition plate for preventing the diluted lubricant from dropping.

  The diesel engine of the embodiment of FIG. 1 includes a piston 2 that reciprocates inside a cylinder 1, and the piston 2 is connected to a crankshaft 4 by a connecting rod 3. This diesel engine is a direct injection engine, and fuel is injected into the cylinder 1 from the fuel injection valve 6 attached to the cylinder head 5 at the end of the compression stroke, and the piston 2 is pushed down by combustion of the injected fuel to crank. The shaft 4 is rotated. This engine is provided with a so-called DOHC type valve operating mechanism, and cam shafts of the intake valve 7 and the exhaust valve 8 are installed in the cylinder head 5, and the cam shaft is known as a chain, a toothed belt, etc. It is driven by the crankshaft 4 via An exhaust pipe 9 connected to the exhaust valve 8 is equipped with a NOx occlusion reduction catalyst 10, and an additional fuel supply valve 11 for supplying additional fuel when NOx is reduced is placed upstream of the exhaust pipe 9.

  A crankcase 12 is integrally formed at a lower portion of the cylinder block provided with the cylinder 1, and an oil pan 13 is attached below the crankcase 12. Although not shown, the oil pan 13 is provided with an oil pump similar to that of the diesel engine shown in FIG. 6 (a), and the oil stored in the oil tank below the oil pan 13 is sucked and cranked. The pressure is fed to the bearing portion of the shaft 4 and the valve mechanism of the cylinder head 5. The lubricating oil after lubricating these portions falls to the oil pan 13, is collected in the oil tank, and circulates again to the oil pump. Part of the lubricating oil pumped by the oil pump is supplied to the cylinder 1 by a lubricating oil supply mechanism similar to that shown in FIG. 5, and forms an oil film on the sliding surface. The lubricating oil supplied to the cylinder 1 is also scraped off by the piston ring and falls downward.

  In the diesel engine of FIG. 1 which is an embodiment of the present invention, a partition plate 14 through which the connecting rod 3 passes is installed below the cylinder 1. The partition plate 14 prevents the lubricating oil supplied to the cylinder 1 from dropping into the oil pan 13 and moves in the left-right direction in FIG. 1 according to the swinging of the connecting rod 3 as the piston 2 reciprocates. However, it has a size so as to cover the entire bottom of the cylinder 1 over the entire moving range.

As shown in FIG. 2, the partition plate 14 has a through hole 14 </ b> A through which the connecting rod 3 penetrates at the center, and both ends are pivotally attached to the upper end of the lever 15 by pins. An intermediate pin 17 that is supported by a column 16 formed integrally with the crankcase 12 is provided at an intermediate portion of the lever 15, and the lever 15 can swing around the intermediate pin 17. A cam 18 is in contact with the lower end of the lever 15, and this cam 18 is driven by the crankshaft 4 via a chain or the like as shown by a two-dot chain line in FIG. Rotate. That is, the partition plate 14 is configured to move to the left and right by the cam 18 following the movement of the connecting rod 3 that swings left and right as the crankshaft 4 rotates, and the connecting rod 3 and the partition plate 14 interfere with each other. Will not cause. A sealing elastic body 14 </ b> B that contacts the connecting rod 3 is provided in the through hole 14 </ b> A of the partition plate 14 so as to seal the gap between the connecting rod 3 and the partition plate 14 even when the connecting rod 3 is inclined.
A blocking wall 14 </ b> C is installed at one end of the partition plate 14 to prevent the lubricant from falling. On the other end side of the partition plate 14, a bowl-shaped diluted lubricant receiver 19 is integrated with the crankcase 12. Formed.

  As indicated by broken line arrows in FIG. 2, the lubricating oil after lubricating the cylinder 1 and the piston 2 falls on the partition plate 14 from above and accumulates on the upper surface of the partition plate 15. Since the blocking wall 14C is installed at one end of the partition plate 14, the lubricating oil accumulated on the upper surface of the partition plate 14 flows to the other end side (the left side in FIG. 2) of the partition plate 14, and from here the diluted lubricating oil It falls on the receiver 19 and passes through the discharge hole of the crankcase 12 and is recovered by the diluted lubricating oil recovery device 20 (FIG. 1). Thus, the lubricating oil mixed with the fuel component and diluted after lubricating the cylinder 1 is prevented from falling onto the oil pan 13 by the partition plate 14, and is separately collected in the diluted lubricating oil receiver 19 and diluted. It is recovered by the oil recovery device 20. Since the lubricating oil returned from the cylinder 1 is not mixed with the lubricating oil in the oil tank, the lubricating oil supplied to the bearing portion of the crankshaft 4 deteriorates due to dilution with fuel or mixing of soot and the like. It is prevented from waking up.

  The diluted lubricating oil recovery device 20 (FIG. 1) is provided with a separation device, which will be described later, where fuel and lubricating oil are separated. The separated fuel is sent to the added fuel supply valve 11 installed upstream of the NOx occlusion reduction catalyst 10 in the exhaust pipe 9 as shown by a broken line arrow in FIG. 1, and the exhaust gas is reduced when reducing NOx. It is used as an additive fuel for creating an atmosphere. The separated lubricating oil is returned to the oil tank of the oil pan 13 through the pipe line 21.

  The partition plate 14 ′ for preventing the diluted lubricating oil drop in the modification of FIG. 3 is to be moved left and right using the swing of the connecting rod 3. In this modification, a partition wall 12A extending in the horizontal direction is formed integrally with the crankcase 12 between the cylinder 1 and the crankshaft 4 so that the partition plate 14 'slides on the partition wall 12A. It is configured. A bearing body 14B 'having a circular cross section is fitted into the through hole 14A' of the partition plate 14 'through which the connecting rod 3 passes, and the outer peripheral surface of the bearing body 14B' is fitted to the partition plate 14 'at the edge of the through hole 14A'. A bearing receiving portion 14C ′ corresponding to is formed. The connecting rod 3 is fitted in a hole provided in the center of the bearing body 14B ', and swings left and right while sliding in the hole.

  In the engine of the modification shown in FIG. 3, the cylinder 1 and the oil pan 13 are entirely divided by the partition wall 12A and the partition plate 14 'sliding on the partition wall 12A. The lubricating oil dropped from the cylinder 1 and accumulated on the upper surfaces of the partition wall 12A and the partition plate 14 'passes through the discharge hole of the crankcase 13 and is diluted with the lubricating oil recovery device, as in the embodiment of FIGS. 20 (FIG. 1). In this way, in the engine of the modification of FIG. 3, the cylinder 1 and the oil pan 13 are completely cut off, so that it is possible to reliably prevent the diluted lubricating oil from falling into the oil tank. Further, since the partition plate 14 ′ is directly moved left and right by the connecting rod 3, the driving device for the partition plate 14 ′ becomes very simple.

Next, the separation device provided in the diluted lubricating oil recovery device 21 will be described based on the schematic diagram of FIG.
As shown in FIG. 4A, the separation device includes a rotor 31 that is rotationally driven by a motor M, and a plurality of blades 32 are attached to a diameter enlarged portion of the rotor 31. As shown in FIG. 4 (b), the blade 32 is formed by twisting the root portion while bending an elongated plate material, and is fixed so that the root portion of the blade 32 is inclined with respect to the circumferential direction of the enlarged diameter portion. Is done. The casing 33 that houses the rotor 31 is provided with an introduction port 34 for introducing diluted lubricating oil dropped from the cylinder 1 to the partition plate 14 and the like, and a fuel recovery port 35 is provided to collect the separated fuel and lubricating oil. The lubricating oil recovery port 36 is placed in the vicinity of the center portion of the rotor 31.

Diluted lubricating oil mixed with fuel and diluted is sucked from the inlet 34 and sent to the right side of the figure by the rotating blade 32. At this time, the lubricating oil having a viscosity higher than that of the fuel adheres to the root portion of the rotating blade 32 and flows in the vicinity of the surface of the diameter-enlarged portion of the rotor 31, and is collected from the lubricating oil collection port 36 to the oil pan 13. Returned. On the other hand, the low-viscosity fuel is blown off in the outer circumferential direction by the rotating blades 32 and gathers at the fuel recovery port 35 and is sent from there to the added fuel supply valve 11 (see FIG. 1), and is exhausted when NOx is reduced. It is used as an additive fuel for making gas into a reducing atmosphere.
Although the separation apparatus of the embodiment of FIG. 4 uses single stage blades 32, a plurality of blades may be arranged in the axial direction to constitute a multistage separation apparatus. In addition, a different type of separation device such as a separation device using a difference in evaporation temperature disclosed in Patent Document 1 can be employed.

  As described in detail above, the present invention provides a lubricating plate in which a partition plate that moves in response to the swinging of the connecting rod is installed below the cylinder, and lubricating oil diluted with fuel is supplied to other parts of the engine. The oil is collected separately from the oil to prevent dilution and deterioration of the lubricating oil in the entire lubrication system. In the above embodiment, the case where the present invention is applied to a diesel engine equipped with an NOx occlusion reduction catalyst in the exhaust pipe has been described. However, the present invention is not limited to a diesel engine that performs post-injection during DPF regeneration, or lubrication It can be widely applied to gasoline engines and the like where oil dilution is a problem. Further, in the above embodiment, the diluted lubricating oil on the partition plate is discharged from one side of the crankcase, but various modifications can be made to the above embodiment, such as a configuration in which it is discharged from both sides. Obviously there is.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 3 Connecting rod 4 Crankshaft 12 Crankcase 13 Oil pan 14, 14 'Partition plate 18 Cam 19 Diluted lubricating oil receiver 20 Diluted lubricating oil collection | recovery apparatus

Claims (5)

An engine having a piston that reciprocates inside a cylinder, wherein the piston is connected to a crankshaft by a connecting rod;
The engine includes an oil pump that pumps lubricating oil and an oil tank that is installed below the crankshaft and collects and stores the lubricating oil, and a part of the lubricating oil is transferred from the oil pump to the cylinder. Configured to be supplied, and
Between the cylinder and the crankshaft, there is provided a partition plate that has a through hole through which the connecting rod penetrates and moves according to the swinging of the connecting rod, and lubrication that falls from the cylinder to the partition plate. An engine comprising a diluted lubricating oil recovery device for recovering oil. The engine according to claim 1, wherein a partition wall is formed between the cylinder and the crankshaft, and the partition plate moves on the partition wall. The engine according to claim 1 or 2, wherein the diluted lubricating oil recovery device is provided with a separating device that separates the lubricating oil and the fuel, and the separated lubricating oil is returned to the oil tank. The engine according to claim 3, wherein the separation device has rotating blades. The engine according to claim 3, wherein the engine is a diesel engine having an added fuel supply device in an exhaust pipe, and the fuel separated by the separation device is supplied to the exhaust pipe as an added fuel.

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