JP4206059B2 - Oil drain structure of blow-by gas recirculation system - Google Patents

Description

  The present invention relates to an oil drain structure of a blow-by gas recirculation device.

Conventionally, an oil mist separator for separating oil mist in the blow-by gas is provided in a rocker cover attached to the upper part of the cylinder head in order to process blow-by gas blown through from the combustion chamber of the engine to the valve chamber.
That is, conventionally, the camshaft mounted on the cylinder head is used to open and close (valve drive) the exhaust valve, and the oil that lubricates the camshaft is splashed onto the camshaft.

For this reason, oil is mixed in blow-by gas blown from the combustion chamber into the valve-operating chamber or the like, so that an oil mist separator for separating the oil mist in the blow-by gas is provided in the rocker cover (patent) References 1 and 2).
As a measure to prevent HC emissions, the blow-by gas from which the oil mist has been separated returns to the engine intake system via the blow-by gas recirculation path connected to the rocker cover, and the oil separated by the oil mist separator is blow-by. It filtered with the oil filter with which it attached in the gas recirculation | reflux path | route, and as shown in FIG. 3, it returned directly to the oil pan through the drain tube connected to the cylinder block of the engine from the said oil filter.
JP-A-8-93434 JP 2000-220436 A

However, in this conventional oil drain structure, the oil level of the drain tube and the oil pan are close, and the internal pressure of the crankcase is higher than the intake negative pressure. There was a problem that oil drained through the drain tube and the oil filtered by the oil filter was difficult to return into the crankcase.
The present invention has been devised in view of such circumstances, and blowby gas that prevents backflow of oil mist from the engine crankcase to the intake system and facilitates returning the oil filtered by the oil filter into the crankcase. An object is to provide an oil drain structure of a reflux device.

  In order to achieve such an object, the oil drain structure of the blow-by gas recirculation device according to claim 1 is mounted in a blow-by gas recirculation path between a rocker cover attached to the cylinder head of the engine and the intake system of the engine. A drain tube is connected between the oil filter that filters the oil in the blow-by gas separated by the oil mist separator in the cover and the air compressor that is attached to the engine, and the oil that has been filtered by the oil filter is removed from the air compressor. It returns to an oil pan through a wheel housing.

  According to the invention of claim 1, it is possible to provide an oil drain structure of a blow-by gas reduction device that prevents backflow of oil mist using existing equipment without adding backflow prevention parts, The oil filtered by the oil filter can be reliably returned to the oil pan.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a diesel engine having an oil drain structure according to an embodiment of the present invention. In the figure, 1 is a rocker cover that is attached to the upper part of a cylinder head 5 of a diesel engine (hereinafter referred to as “engine”) 3. The rocker cover 1 is formed in a substantially U-shaped cross section that opens on the cylinder head mounting portion 7 side that is attached to the cylinder head 5.

  Thus, an oil mist separator (not shown) for separating the oil mist in the blow-by gas blown out from the combustion chamber of the engine 3 is provided inside the rocker cover 1, and the oil mist is separated by the oil mist separator. The blow-by gas from which the gas is separated flows back to the intake system of the engine through a blow-by gas recirculation path 11 formed of a pipe connected to the gas outlet portion 9 of the rocker cover 1.

  As in the prior art, an oil filter 13 for filtering the oil separated by the oil mist separator is mounted in the blow-by gas recirculation path 11. In this embodiment, the oil filtered by the oil filter 13 is used. Instead of the conventional structure directly returned into the cylinder block 15, a drain tube 21 is connected between the oil filter 13 and the air compressor 19 attached to the timing gear case 17 behind the engine 3, and the oil filtered by the oil filter 13 is used. Is first returned to the air compressor 19 through the drain tube 21.

  As conventionally known, the air compressor 19 is a supply device for obtaining compressed air necessary as a power source for a brake air booster or the like, and mainly includes a crankcase 23, a cylinder liner 25, and a cylinder head 27. The crankshaft in the crankcase 23 is supported by a ball bearing assembled in the crankcase 23, and a drive injection pump gear is splined on the rear end side (engine rear side) protruding into the timing gear case 17. It is fitted and attached.

  Conventionally, the oil for lubricating the air compressor 19 is taken out from the cylinder block 15, enters the crankcase 23, lubricates the inside, and then returns to the timing gear train in the timing gear case 17. As described above, in this embodiment, the drain tube 21 is connected between the oil filter 13 and the air compressor 19, and the oil filtered by the oil filter 13 is introduced into the crankcase 23.

Therefore, the oil introduced into the crankcase 23 from the drain tube 21 is lubricated inside together with the oil for lubricating the air compressor 19 and then returned to the timing gear train.
Since the timing gear train is disposed on the flywheel side and covered with the flywheel housing 29 in which the gear housing 28 is integrally formed, the oil returned to the timing gear train is supplied to the flywheel housing 29 (gear housing). 28), the oil pan 31 is attached to the lower part of the cylinder block 15.

  The oil path of the oil drain structure according to the present embodiment is shown in the flowchart of FIG. 2, and in this way, the present embodiment directly returns the oil filtered by the oil filter into the cylinder block. Instead, such an oil path is adopted, and the oil path is more complicated than the conventional structure shown in FIG.

  Therefore, according to the present embodiment, it is possible to provide an oil drain structure of a blow-by gas reduction device that prevents backflow of oil mist using existing equipment without adding backflow prevention parts. There is an advantage that the oil filtered by the filter 13 can be reliably returned to the oil pan 31.

1 is an overall perspective view of an engine using an oil drain structure of a blow-by gas recirculation device according to one embodiment of the present invention. It is a flowchart of the oil drain structure which concerns on one Embodiment of Claim 1. It is a flowchart of the oil drain structure in the conventional blow-by gas recirculation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rocker cover 3 Engine 5 Cylinder head 9 Gas outlet part 11 Blow-by gas recirculation path 13 Oil filter 15 Cylinder block 17 Timing gear case 19 Air compressor 21 Drain tube 29 Flywheel housing 31 Oil pan

Claims (1)

An oil filter that is mounted in a blow-by gas recirculation path between a rocker cover that is attached to the cylinder head of the engine and an intake system of the engine, and that filters oil in the blow-by gas separated by an oil mist separator in the rocker cover;
Connect the drain tube to the air compressor that is attached to the engine,
An oil drain structure for a blow-by gas recirculation device, wherein oil filtered by an oil filter is returned from the air compressor to an oil pan through a flywheel housing.

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