JPS6056890B2 - Blow-by gas treatment device for internal combustion engine with turbo charger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a blow-by gas treatment device used in an internal combustion engine for an automobile, and more particularly to a blow-by gas treatment device suitable for an internal combustion engine equipped with a turbocharger.

The structure of blow-by gas processing equipment that processes unburned gas or combustion generated gas that blows into the crankcase from the gap between the piston and cylinder wall during the compression stroke of an internal combustion engine includes open system, closed system, and shield system. The invention is an improvement to a closed system.

A closed system generally has a structure in which the crankcase and the intake manifold are connected through a passage with a PCV valve, and the rocker cover and the clean side of the air clear are connected through a passage to suck blow-by gas from the crankcase.

When the internal combustion engine rotates under partial load and the intake negative pressure at the intake manifold is relatively strong, blow-by gas is sucked from the crankcase into the intake manifold along with fresh gas that enters the crankcase from the air cleaner through the rocker cover. When the internal combustion engine rotates under full load and the suction negative pressure is weak, blow-by gas is sucked from the crankcase through the rocker cover to the clean side of the air cleaner. At this time, the absolute amount of blow-by gas is large, so there is no need to introduce a new party. (Tokuko Showa 47-2961
(Refer to Publication No. 4 and Japanese Utility Model Publication No. 47-36163.) When this closed system is adopted in an internal combustion engine with a turbocharger, when the turbocharger is operating, the intake manifold becomes positive pressure due to the influence of supercharging pressure, and the combustion Because the turbocharger fills the engine with a large amount of air-fuel mixture, the amount of blow-by gas that leaks into the crankcase chamber from the gap between the piston and cylinder wall is also greater than in an internal combustion engine without a turbocharger.

In addition, due to the boost pressure of the turbocharger, the conventional PCV valve, which is installed in the passage connecting the crankcase and intake manifold, closes earlier than in an internal combustion engine without a turbocharger. often enters the clean side of the air cleaner, that is, the intake passage upstream of the turbocharger, through the rocker cover. Due to the influence of this absolutely large flow of blow-by gas, the lubricating oil supplied inside the rocker cover is also sucked out at the same time, promoting the evaporation of the lubricating oil. There is a problem that there is a shortage of lubricating oil to the engine, and combustion performance deteriorates due to the release of non-flammable lubricating oil gas into the intake system.
This invention provides a first passage having a PCV valve that communicates between the crankcase and the intake manifold, and a second passage that communicates between the rocker cover and the intake passage on the upstream side of the turbocharger.
In addition to the passage, there is a third passage that communicates between the crankcase and the intake passage upstream of the turbocharger, and during partial load, blow-by gas is sucked into the intake system from the first passage.
At high loads, blow-by gas is sucked into the intake system from the second and third passages to reduce the flow rate toward the rocker cover, thereby solving the above-mentioned problems.

This invention will be explained in detail by way of examples. FIG. 1 shows a blow-by gas processing apparatus according to the present invention, in which 1 is an engine block, 2 is a rocker cover, and 3 is a crankcase.

4 is an intake manifold attached to the engine block 1.

5 is a carburetor having a throttle valve 5a.

A turbocharger 7 installed upstream of the carburetor is an intake passage, and 8 is an air cleaner.

Reference numeral 9 designates a first passage for blow-by gas that communicates between the crankcase 3 and the intake manifold 4, and 10 represents a PC valve that adjusts the amount of blow-by gas flowing through the first passage.

The structure of the PC valve 10 is as shown in A of FIG. 2 and is conventionally known. Reference numeral 11 denotes a second passage for blow-by gas that communicates between the fuel tank cover 2 and the intake passage 7.

Reference numeral 12 denotes a third passage that communicates the crankcase 3 with the intake passage 7 upstream of the turbocharger 6, and is a third passage that communicates with the crankcase 3 and the intake passage 7 upstream of the turbocharger 6. It's bad.

A PCV valve 13 is provided at the connection between the third passage 12 and the intake passage 7 to adjust the amount of blow-by gas. PCV
The structure of the valve 10 and the PCV valve 13 is as shown in FIG. 2A, and is a structure used in many prober and gas reduction devices.

The PCV valve 13 may have the structure shown in FIG. 2B. If this is the case, at partial load, the flow of blow-by gas through the third passage 12 will naturally stop as the negative pressure in the intake passage weakens, and conversely, intake air will not flow towards the crankcase because the valve closes. It is.
Furthermore, since even if the intake air flows, the inside of the crankcase is only cleaned, it is sufficient to simply provide an orifice. Next, the operation will be explained. When the internal combustion engine is rotating at low to medium load, that is, at partial load, blow-by gas flows from the crankcase 3 through the first passage 9, PCV valve 10, and into the intake manifold 4 (in the direction of the dotted arrow in Figure 1). ) It is suctioned by negative suction pressure.

The PCV valve 10 controls the orifice 14 to narrow the flow rate when the suction negative pressure is very strong, and to increase the flow rate when the suction negative pressure is relatively weak. At this time, the turbocharger 6 is hardly driven because the amount of exhaust gas is small, and the negative pressure in the intake passage 7 is small, so no blow-by gas is sucked from the second passage 11 or the third passage 12.

Next, when the internal combustion engine starts rotating at high speed and under high load, the intake negative pressure in the intake manifold 4 decreases as the throttle valve 5a of the carburetor 5 becomes fully open, and the turbocharger 6 is driven again. Since the inside of the intake manifold 4 becomes positive pressure due to boost pressure, the PC installed in the first passage 9
The V-valve 10 is closed, and the blow-by gas is caused by the strong flow of intake air flowing through the intake passage 7 to the rocker cover 2.
The air is sucked through the second passage 11. At this time, since there is the third passage 12 according to the present invention, blow-by gas is also sucked from the third passage 12 (in the direction of the solid arrow in Fig. 1).
. That is, since the blow-by gas is branched into the second passage and the third passage and sucked into the intake system, evaporation of the lubricating oil present in the rocker cover 2 is less likely to be promoted.

Therefore, blow-by gas from a turbocharged internal combustion engine can be reduced and disposed of without adversely affecting other parts.

It can also prevent contamination caused by exhaust gas in the intake system.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an embodiment of a blow-by gas treatment apparatus according to the present invention, and FIGS. 2A and 2B are sectional views of an example of a PC⊂ valve, respectively. 1...Engine block, 2...Rocker cover,
3... Crank case, 6... Turbocharger, 9... First passage, 11... Second passage, 12...
Third aisle.

Claims (1)

[Claims] 1. A first passage having a PCV valve that communicates between the crankcase and the intake manifold, a second passage that communicates between the rocker cover and the intake passage on the upstream side of the turbocharger, and a second passage that communicates between the rocker cover and the intake passage on the upstream side of the turbocharger. A third passage is provided that communicates with the intake passage, and during partial load, the first
A blow-by gas treatment device for an internal combustion engine equipped with a turbocharger, characterized in that blow-by gas is sucked into the intake system from a passage, and when the load is high, blow-by gas is sucked into the intake system from a second passage and a third passage. 2. The blow-by gas treatment device for an internal combustion engine with a turbocharger according to claim 1, wherein the third passage has a PCV valve.