JPH0627783Y2 - Oil separator for PCV system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a first PCV chamber connected to an upstream side of a throttle valve in a head cover of an engine, and a second PCV chamber connected to a downstream side of a throttle valve via a PCV valve. The present invention relates to a crankcase ventilation (hereinafter referred to as PCV) system having a PCV chamber.

[Prior Art] Conventionally, a PCV system having a first PCV chamber and a second PCV chamber as described above is disclosed in, for example, Japanese Utility Model Laid-Open No. 58-17.
No. 8404. Such a PC
In the V device, the fresh air from the upstream of the throttle valve enters the first PCV chamber, scavenges the oil mist in the head cover and enters the second PCV chamber, and then from the second PCV chamber to the PCV chamber.
Through the valve, the negative pressure of the intake manifold sucks it to the downstream side of the throttle valve, thus circulating fresh air to scavenging blow-by gas and preventing oil deterioration.

In the conventional PCV device, the first PCV chamber and the second PCV chamber
The chambers are isolated from each other by a partition, and the first PC
Scavenging air from the V chamber always flows into the second PCV chamber through the space just above the oil surface in the head cover.

[Problems to be solved by the invention] When the load is low, the throttle is throttled and the negative pressure on the downstream side becomes large. In the area A in FIG. 4, the flow rate is high, and the amount of blow-by gas generated is particularly high at high speeds, so the pressure in the head cover is lower than in the crankcase (due to the negative pressure in the intake system), and the oil is returned. If the block uses both the passage and the blow-by gas passage in the block, the upward flow of blow-by gas may prevent the oil from returning and the oil level may rise, causing the possibility of oil blowout (oil is directly sucked). Occurs.

As the load decreases, the valve body of the PCV valve 80 rises in FIG. 5 and the flow rate increases, but if the negative pressure is too strong, the flow passage at the tip of the valve body in FIG. It becomes smaller and the flow rate decreases (region B in FIG. 4).
Especially when a large amount of blow-by gas is generated at high speed,
In the region of B in the figure, since a large amount of blow-by gas flows toward the fresh air introduction side, the oil separation capacity tends to be insufficient, which causes a problem that oil removal to the intake system increases.
More specifically, if the PCV chamber connected to the fresh air introduction side has a sufficient nominal volume, the oil separation capacity will not be insufficient (the blow-by gas accelerated by the holes in the separator plate is P
When entering the CV chamber and decelerating, the oil and air are separated due to the difference in inertia between the oil and air, so the PCV chamber must be able to decelerate the blow-by gas with a sufficient volume), the fresh air introduction side and the PCV valve side. It is usually difficult to secure a large-volume PCV chamber together with the maximum flow rate of 1 due to the restriction of the space around the engine. Therefore, when the maximum flow rate flows in a place where the PCV chamber volume corresponding to the maximum flow rate cannot be secured, the oil separation capacity insufficiency such as at the time of high rotation in the region B above occurs.
The problem to be solved by the present invention is to solve the above-mentioned increase in oil removal in the area B of FIG.
(However, in this case, the upstream side of the throttle valve may be close to the atmospheric pressure, and the rise in the oil level is mainly due to the increase in the supply amount due to the high rotation of the pump and the increase in the blow-by gas generation amount. The problem of oil level rise is not particularly solved by the present invention.) Moreover, even if the rotation speed becomes high in the medium and high load range and the amount of blowby gas generated exceeds the flow rate of the PCV valve, Since it is dispersed on both the PCV valve side and the fresh air introduction side, it is not a problem as much as B part.

[Means for Solving Problems] According to the present invention, the above-mentioned problems are caused in the head cover.
A first PCV chamber connected to the upstream side of the throttle valve;
In a PCV system having a second PCV chamber connected to the downstream side of the throttle valve via a PCV valve, a dead space separate from the blow-by gas path is provided in each of the first PCV chamber and the second PCV chamber, First P
A PCV provided with a through hole that connects both dead spaces to the partition wall between the dead space in the CV room and the dead space in the second PCV room to allow the flow of blow-by gas at all times.
Achieved by the system oil separator.

[Operation] In the oil separator of the present invention described above, a large amount of blow-by gas generated in the high rotation and low load region is conventionally flowed from the second PCV chamber to the throttle valve downstream side by the PCV valve characteristic (high rotation and low load). Since the flow rate is limited by the characteristic that the flow rate is small depending on the area load, most of the flow was discharged from the first PCV chamber to the upstream side of the throttle valve, whereas in the present invention, blow-by gas is discharged to the second PC.
Since it also flows from the V chamber to the first PCV chamber through the through hole, it is discharged to the upstream side of the throttle valve through both the first PCV chamber and the second PCV chamber, and the volume and oil of the PCV chamber are increased. Cutting performance will be almost doubled compared to the conventional one. Therefore, the oil removing performance is improved.

Further, since the through hole of the partition wall is provided between the dead spaces of both PCV chambers, even when fresh air is introduced from the upstream side of the throttle valve in the normal operating range,
The amount of fresh air that bypasses the space above the cylinder head and flows directly from the first PCV chamber to the second PCV chamber through the through hole is very small, and most of the fresh air is introduced into the space inside the head cover. , Ventilation performance (scavenging of blow-by gas)
It can be said that there is almost no deterioration.

[Embodiment] Hereinafter, a preferred embodiment of the oil separator of the PCV system according to the present invention will be described with reference to the drawings.

1 to 3 show the oil separator of the PCV system of the present invention. The oil separator of the PCV system generally includes a cylinder head cover 10, a separator plate 40 fixed to the cylinder head cover 10 and defining a first PCV chamber 20 and a second PCV chamber 30 between the cylinder head cover 10 and the cylinder head cover 10. A partition wall 50 that separates the PCV chamber 20 from the second PCV chamber 30, a through hole 60 formed in the partition wall 50, a fresh air port 70 that connects the first PCV chamber 20 to the upstream side of the throttle valve of the engine intake system, and a first The PCV valve 80 connects the second PCV chamber 30 to the downstream side of the throttle valve of the engine intake system.

The cylinder head cover 10 includes four side walls 11 having a lower end fastened to the cylinder head and extending substantially vertically, and side walls 11.
An upper wall 12 extending substantially horizontally at the upper end of the
A rib 13 extending downwardly from. The ribs 13 form side walls of the first PCV chamber 20 and the second PCV chamber 30.

The separator plate 40 is attached to the lower end of the rib 13, and the separator plate 40 and the upper wall 12 of the cylinder head cover 10 are attached.
A space surrounded by the rib 13 and the rib 13 constitutes a PCV chamber.
The PCV chamber is composed of a first PCV chamber 20 and a second PCV chamber 30, and the first PCV chamber 20 and the second PCV chamber 30 are arranged in series in the longitudinal direction of the engine and adjacent to each other. The separator plate 40 includes a first separator plate 41 and a second separator plate 42 fixed to the first separator plate 40. The first separator plate 41 has ribs 13 at its center in the longitudinal direction.
Extends in a substantially horizontal direction at the lower end of the, and extends in a substantially horizontal direction offset downward at both ends in the longitudinal direction. In this downwardly offset portion, a plurality of plates are cut and raised obliquely upward so that a plurality of holes 43 are formed to allow the blow-by gas to pass while cutting oil. The second separator plate 42 is attached so as to correspond to the portion of the first separator plate 41 in which the hole 43 is formed. The second separator plate 42 covers the hole 43 with a space from below, and It opens toward the direction. Blow-by gas flows through this opening 44 and is drained.

The fresh air port 70 is the first PC of the cylinder head cover 10.
It is opened in the side wall of the V chamber 20 and is provided at a position relatively close to the hole 43 at one end of the separator plate 40, whereby a normal blow-by gas path is provided in the first PCV chamber 20. The dead space 21 is configured so as not to be directly configured, that is, to be removed from the blow-by gas path. The opening port of the PCV valve 80 to the second PCV chamber 30 is provided at a position relatively close to the hole 43 at the other end of the separator plate 40, whereby the second PCV chamber 30 is opened.
A dead space 31 that does not directly form a normal blow-by gas path is formed therein.

The partition wall 50 extends downward from the upper wall of the cylinder head cover 10, and is formed by the dead space 21 of the first PCV chamber 20 and the second PC.
The dead spaces 31 of the V chamber 30 are separated from each other.

The partition wall 50 is provided with a through hole 60 that allows the dead space 21 of the first PCV chamber 20 and the dead space 31 of the second PCV chamber 30 to communicate with each other at all times to allow the flow of blow-by gas. The through hole 60 is composed of, for example, a hole formed by cutting out the lower end of the partition wall 50 and being surrounded by the cutout portion and the first separator plate 41. The through hole 60 is offset from the center axis of the engine in the width direction toward the port 70.

Next, the operation of the above embodiment will be described.

When the amount of blow-by gas generated increases and the PCV indoor pressure becomes positive in the high engine speed and low load region, the blow-by gas flows from the first PCV chamber 20 to the upstream side of the throttle valve and from the second PCV chamber 30. Also flows through the through hole 60 to the first PCV chamber 20 and flows to the upstream side of the throttle valve. (From the second PCV chamber 30 to the PCV valve
Although the flow rate through the 80 to the downstream side of the throttle valve is the same as in the past, the flow rate in this area (area B in FIG. 4) is small due to the characteristics of the PCV valve 80. ) For this reason, PC
The volume of the V chamber is almost doubled as compared with the conventional one, and the oil draining mechanism at both ends of the separator plate 40 effectively works to double the oil draining performance.

Also, regarding ventilation, the first from the throttle valve upstream
The fresh air is introduced into the PCV chamber 20 of the separator plate 40, and the fresh air passes through the hole 43 and the opening 44 at one end of the separator plate 40 to the space inside the cylinder head, and passes through the opening and the hole 43 at the other end of the separator plate 40. Enters the second PCV chamber 30 and the PCV valve 80
It must be circulated over the blow-by gas scavenging as it is drawn through to the throttle valve downstream. Partition 50
The bypass of this ventilation flow by the through hole 60 formed in the above must be suppressed in order to obtain sufficient scavenging. Dead space in the first PCV room 20
21 is provided, and a dead space 31 is also provided in the second PCV chamber 30. Through holes 6 are provided so that both dead spaces 21 and 31 communicate with each other.
Since 0 is provided, the through hole 60 exists at a position deviated from the PCV path, and the fresh air flowing from the first PCV chamber 20 through the through hole 60 to the second PCV chamber 30 directly. The amount is suppressed to a very small amount, and there is almost no deterioration in ventilation performance.

[Effect of the Invention] According to the oil separator of the PCV system of the present invention,
Since the first PCV chamber 20 and the second PCV chamber 30 are communicated with each other by the through hole 60 that allows the blow-by gas to flow at all times, the second PCV chamber can be used even in the high engine speed and low load region.
A blow-by gas flow that flows from the chamber 30 through the first PCV chamber 20 to the upstream of the throttle valve is generated, the capacity of the oil separator is increased, and the amount of oil carried away from the PCV chamber to the upstream of the throttle valve is reduced. This reduces oil consumption.

Further, since the through hole 60 is provided in the partition wall 50 that separates the dead space 21 formed in the first PCV chamber 20 and the dead space 31 formed in the second PCV chamber 30, the through hole 60 is provided in the PCV.
It can be removed from the path, and bypass of fresh air can be suppressed regardless of the provision of the through hole 60, and good ventilation performance can be maintained.

[Brief description of drawings]

FIG. 1 is a bottom view of an oil separator of a PCV system according to an embodiment of the present invention at an upper position of a separator plate, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. FIG. 4 is a sectional view taken along the line III-III in FIG. 4, FIG. 4 is an engine load-PCV valve flow rate characteristic diagram of a general PCV valve, and FIG. 5 is a configuration diagram of the PCV valve. 10 ...... Cylinder head cover 20 ...... First PCV chamber 21 ...... Dead space 30 ...... Second PCV chamber 31 ...... Dead space 40 ...... Separator plate 50 ...... Partition wall 60 ...... Through hole 80 ...... PCV valve

Claims (1)

[Scope of utility model registration request] 1. A PCV system having a first PCV chamber connected to an upstream side of a throttle valve and a second PCV chamber connected to a downstream side of a throttle valve via a PCV valve in a head cover. A dead space separate from the blow-by gas path is provided in each of the PCV chamber and the second PCV chamber, and both dead spaces are connected to a partition wall between the dead space in the first PCV chamber and the dead space in the second PCV chamber. The PCV system oil separator is characterized in that a through hole is provided to allow the blow-by gas to flow constantly.