JP2005214184A - Blow-by gas treating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent lubricating oil separated by an oil separator from freezing in a blow-by gas treating system returning blow-by gas after separation of lubricating oil by the separator to intake system of an engine. <P>SOLUTION: In the blow-by gas treating system guiding blow-by gas leaking out of a combustion chamber of an engine 1 and flowing into a crank case at a lower part of a cylinder block 20 to the oil separator 22 via a rocker cover 4 covering a valve system on a cylinder head 3 and returning blow-by gas after separation of lubricating oil by the oil separator 22 to an intake system of the engine 1, an oil return opening 25 communicating to an oil drop hole formed inside is provided near an upper end part on an outside surface of the cylinder block 20 and a lubricating oil return structure to which an oil return pipe 27 of the oil separator 22 is connected is provided at the oil return opening 25. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is directed to blow-by gas processing for introducing blow-by gas leaked from a combustion chamber of an engine and flowing into a crankcase into an oil separator, and returning the blow-by gas after separating the lubricating oil by the oil separator to the intake system of the engine. More specifically, the present invention relates to a blow-by gas processing system that includes a return structure for returning the lubricating oil in the blow-by gas separated by the oil separator to the oil pit of the cylinder block, thereby preventing the lubricating oil from freezing. Is.

This type of conventional blow-by gas processing system leaks from the combustion chamber of the engine and flows into the crankcase, such as unburned gas of fuel contained in the blow-by gas, lubricating oil and exhaust gas in the form of mist As shown in FIG. 5, a rocker that covers the valve operating portion (not shown) on the cylinder head 3 with blow-by gas that has flowed into the crankcase at the bottom of the cylinder block 2 that constitutes the engine 1. The oil is guided to the oil separator 6 through the cover 4 and the breather 5, the lubricating oil in the blow-by gas is separated by the oil separator 6, and the blow-by gas after the separation is taken into the intake system through the blow-by gas return pipe 7. It was supposed to be returned to the pipe 8. The blow-by gas returned to the pipe 8 is combined with the air purified by the air cleaner 10 through the stack duct 9, supercharged by the turbocharger 11, cooled by the intercooler 12, and taken into the intake pipe 13. And then returned to the combustion chamber (not shown) in the cylinder block 2 and combusted together with the fuel. Further, the lubricating oil in the blow-by gas separated by the oil separator 6 is returned to the oil pan 15 via the oil return pipe 14 (see, for example, Patent Document 1).
JP 2002-266621 A (pages 4 to 5 and FIG. 8)

  However, in the blow-by gas processing system described in Patent Document 1, the oil return pipe 14 of the oil separator 6 is connected to the oil pan 15 in a state of being exposed to the outside of the engine 1 for a long time. The pipe 14 is easily affected by the outside air temperature. In particular, in winter or in a cold region, the lubricating oil flowing in the oil return pipe 14 or moisture mixed therein may freeze. In this case, the oil return pipe 14 may be clogged, and the lubricating oil separated by the oil separator 6 may not be returned to the oil pan 15 side. Further, since the oil return pipe 14 is long, the weight is increased accordingly.

  Therefore, the present invention addresses such problems and includes a return structure for returning the lubricating oil in the blow-by gas separated by the oil separator to the oil pit of the cylinder block, thereby freezing the lubricating oil. It is an object of the present invention to provide a blow-by gas processing system that prevents the above-described problem.

  In order to achieve the above object, a blow-by gas processing system according to the present invention provides a rocker that covers blow-off gas that leaks from a combustion chamber of an engine and flows into a crankcase at a lower portion of a cylinder block and covers a valve portion on a cylinder head. In a blow-by gas processing system that guides the oil to the oil separator through the cover and returns the blow-by gas after the oil is separated by the oil separator to the intake system of the engine, the lubricating oil separated by the oil separator is A return structure for returning to the oil pit from the rocker cover formed in the vertical direction inside the block is provided.

With such a configuration, the lubricating oil in the blow-by gas separated by the oil separator is returned to the oil pit formed in the cylinder block by the lubricating oil returning structure, and the oil pan is discharged from the oil pit. Flow down to the side.
The lubricating oil return structure has an oil return port in communication with the oil drop hole in the vicinity of the upper end of the outer surface of the cylinder block, and an oil return pipe of the oil separator is connected to the oil return port. It is. As a result, the lubricating oil in the blow-by gas separated by the oil separator is returned to the oil drop hole from the oil return port provided on the outer surface of the cylinder block via the oil return pipe of the oil separator. It flows down from the pit to the oil pan side.

  According to the first aspect of the invention, the lubricating oil returning structure allows the lubricating oil separated by the oil separator to flow down from the oil pit formed in the cylinder block to the oil pan side and return. At this time, since the cylinder block is affected by heat generated from the combustion chamber of the engine, the lubricating oil separated by the oil separator and returned to the oil pit of the cylinder block is hardly affected by the outside air temperature. Thereby, it is possible to prevent the lubricating oil in the blow-by gas separated by the oil separator from freezing when the engine is operated even in winter or in a cold region. Accordingly, the lubricating oil separated by the oil separator is returned to the oil pan side.

  According to the second aspect of the present invention, the lubricating oil separated by the oil separator is returned to the oil pit from the oil return port of the cylinder block via the oil return pipe, flows down from the oil pit and flows into the oil pan. Can be returned to the side. At this time, since the cylinder block is affected by heat generated from the combustion chamber of the engine, the lubricating oil separated by the oil separator and returned to the oil pit of the cylinder block is hardly affected by the outside air temperature. Thereby, it is possible to prevent the lubricating oil in the blow-by gas separated by the oil separator from freezing when the engine is operated even in winter or in a cold region. Accordingly, the lubricating oil separated by the oil separator is returned to the oil pan side. In addition, the oil return pipe of the oil separator is shortened, and the weight can be reduced accordingly.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an overall schematic diagram showing, for example, a four-cycle engine to which a blow-by gas processing system according to the present invention is applied. In FIG. 1, although not shown in the cylinder block 20 of the engine 1, a piston is fitted in the cylinder so as to be able to reciprocate, and a crankcase is formed below the cylinder block 20. . An oil pan 15 that contains lubricating oil is attached to the lower portion of the crankcase. A cylinder head 3 is attached to the top of the cylinder block 20. An intake pipe 13 for sucking a mixed gas into the cylinder of the cylinder block 2 is connected to one side surface of the cylinder head 3, and the combustion gas in the cylinder is connected to the other side surface of the cylinder head 3. An exhaust passage (not shown) for discharging is connected.

  Further, a rocker cover 4 for covering the intake / exhaust valve operating portion (not shown) is placed on the cylinder head 3. Further, a breather 5 for removing excess oil contained in the blow-by gas is provided on the upper surface of the rocker cover 4. An oil separator 22 is connected to the breather 5 via a blow-by gas inflow pipe 21. The oil separator 22 is a device that separates lubricating oil in blow-by gas, has a built-in PCV valve, and is connected to an intake duct of the cylinder head 3 via a blow-by gas return pipe 23.

  As a result, the blow-by gas that has flowed into the crankcase formed in the lower portion of the cylinder block 20 is sent to the breather 5 through the rocker cover 4 to remove excess oil, and then the blow-by gas inflow pipe is removed. It is led to the oil separator 22 through 21. The blow-by gas after the lubricating oil is separated is returned to the intake duct of the cylinder head 3 through the blow-by gas return pipe 23 by the oil separator 22. The blow-by gas returned to the cylinder head 3 is returned again to the combustion chamber (not shown) in the cylinder of the cylinder block 2 and burned together with fuel.

In FIG. 1, reference numeral 9 indicates a stack duct for sucking air, reference numeral 10 indicates an air cleaner for purifying air, reference numeral 11 indicates a turbocharger, and reference numeral 12 indicates an intercooler.
Here, in the present invention, a return mechanism is provided for returning the lubricating oil separated by the oil separator 22 to an oil dropping hole 24 (see FIG. 2) formed in the vertical direction inside the cylinder block 20. Yes. As shown in FIGS. 2 and 3, this lubricating oil return mechanism is provided with an oil return port 25 in the vicinity of the upper end portion on the outer surface of the cylinder block 20. A return pipe 27 (see FIG. 4) is connected. As shown in FIG. 3, the oil return port 25 of the cylinder block 20 is a hole penetrating through the approximate center of the boss 26 provided on the outer surface of the cylinder block 20, and the movement in the rocker cover 4 shown in FIG. In order to allow the lubricating oil supplied to the valve portion to flow down to the oil pan 15 side, it communicates with an oil dropping hole 24 formed in the longitudinal direction inside the cylinder block 20. An oil return pipe 27 of the oil separator 22 shown in FIG. 4 can be connected to the oil return port 25.

  Thus, the oil return pipe 27 of the oil separator 22 shown in FIG. 4 is connected to the oil return port 25 provided in the vicinity of the upper end portion on the outer surface of the cylinder block 20 shown in FIGS. 1). Therefore, the lubricating oil in the blow-by gas separated by the oil separator 22 shown in FIG. 1 is returned to the oil dropping hole 24 (see FIG. 3) from the oil return port 25 of the cylinder block 20 through the oil return pipe 27. As shown by the arrow in FIG. 3, it can flow down from the oil dropping hole 24 and return to the oil pan 15 side.

  At this time, since the cylinder block 20 shown in FIG. 1 is affected by the heat generated from the combustion chamber, the lubricating oil separated by the oil separator 22 and returned to the oil dropping hole 24 of the cylinder block 20 has an outside air temperature. It becomes difficult to be affected. Thereby, it is possible to prevent the lubricating oil separated by the oil separator 22 from freezing when the engine 1 is operated even in winter or in a cold region. Therefore, since the lubricating oil in the blow-by gas separated by the oil separator 22 is returned to the oil pan 15 side, it is possible to prevent the lubricating oil from being wasted. Further, since the oil return pipe 27 of the oil separator 22 shown in FIG. 4 is shorter than the conventional oil return pipe 14 shown in FIG. 5, the overall weight of the apparatus can be reduced.

  In the above description, the lubricating oil return structure is such that the oil return pipe 27 of the oil separator 22 is connected to the oil return port 25 provided near the upper end on the outer surface of the cylinder block 20. However, the present invention is not limited to this, and the oil return port 25 may be provided at any position as long as the lubricating oil is returned to the oil dropping hole 24 formed in the cylinder block 20.

1 is an overall schematic diagram showing, for example, a four-cycle engine to which a blow-by gas processing system according to the present invention is applied. It is a perspective view which shows the cylinder block applied to the blowby gas processing system by this invention. FIG. 3 is a sectional view taken along line XX in FIG. 2. It is explanatory drawing which shows the oil separator applied to the blowby gas processing system by this invention. It is a whole schematic diagram which shows the engine to which the conventional blowby gas processing system was applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine 3 ... Cylinder head 4 ... Rocker cover 5 ... Breather 13 ... Intake pipe 20 ... Cylinder block 21 ... Blow-by gas inflow pipe 22 ... Oil separator 23 ... Blow-by gas return pipe 24 ... Oil pit 25 ... Oil return port 27 ... Oil Return pipe

Claims (2)

The blow-by gas that leaks from the combustion chamber of the engine and flows into the crankcase at the bottom of the cylinder block is guided to the oil separator through the rocker cover that covers the valve operating portion on the cylinder head, and lubricating oil is supplied by the oil separator. In the blow-by gas processing system that returns the blow-by gas after separation to the intake system of the engine,
A blow-by gas processing system comprising a return structure for returning the lubricating oil separated by the oil separator to an oil pit from the rocker cover formed in the longitudinal direction inside the cylinder block.   The lubricating oil return structure is characterized in that an oil return port communicating with the oil drop hole is provided near the upper end of the outer surface of the cylinder block, and an oil return pipe of the oil separator is connected to the oil return port. The blowby gas processing system according to claim 1.

Images