JP5351801B2 - Engine blow-by gas recirculation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine blow-by gas reflux device which enhances the ventilation efficiency of a crankcase. <P>SOLUTION: A fresh air introduction chamber 10 is provided next to the crankcase 9, and an upstream side intake passage 7 of a throttle valve 5 is brought in communication with the fresh air introduction chamber 10. The fresh air introduction chamber 10 is brought in communication with the crankcase 9 through a throttle hole 11 facing the crankcase 9, and a check valve 29 is provided in a passage outlet 8a of a fresh air introduction passage 8 for inhibiting a reverse flow, so that fresh air 12 in the upstream side intake passage 7 of the throttle valve 5 is introduced into the crankcase 9 while passing through the fresh air introduction passage 8, etc. sequentially, in a reverse flow, gas in the crankcase 9 reversely flows into the upstream side intake passage 7 of the throttle valve 5 while passing through the throttle hole 11, the fresh air introduction chamber 10, a valve clearance 30 of the check valve 29 and the fresh air introduction passage 8 sequentially, and when gas pressure acting on the check valve 29 exceeds a predetermined value, the reverse flow is blocked through full closure of the check valve 29. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an engine blow-by gas recirculation device, and more particularly to an engine blow-by gas recirculation device that can increase the ventilation efficiency of a crankcase.

2. Description of the Related Art Conventionally, as a blow-by gas recirculation device for an engine, a PCV valve is attached to a head cover attached to a cylinder head, and this PCV valve communicates with a downstream intake passage of a throttle valve via a blow-by gas passage. Is connected to the crankcase via a fresh air introduction passage (see Patent Document 1).
According to this type of device, the blow-by gas in the crankcase is recirculated by the ventilation of the crankcase, so that the deterioration of the blow-by gas mixed into the engine oil stored below the crankcase can be suppressed. There is.
However, this conventional technique has a problem because the fresh air introduction passage communicates with the crankcase through the head cover.

JP 2002-213226 A (see FIG. 3)

<Problem> Ventilation of the crankcase may be insufficient.
Since the fresh air introduction passage communicates with the crankcase through the head cover, fresh air introduced from the fresh air introduction passage may be short-circuited from the head cover to the PCV valve, resulting in insufficient ventilation of the crankcase.

  An object of the present invention is to provide an engine blow-by gas recirculation device that can increase the ventilation efficiency of a crankcase.

(Invention of Claim 1)
Invention specific matters of the invention according to claim 1 are as follows.
As illustrated in FIG. 1, a PCV valve (3) is attached to a head cover (2) attached to a cylinder head (1), and this PCV valve (3) is connected to a throttle valve (5) via a blow-by gas passage (4). The blow-by gas of the engine is connected to the downstream intake passage (6) of the engine, and the upstream intake passage (7) of the throttle valve (5) is connected to the crankcase (9) via the fresh air introduction passage (8). In the reflux device,
As illustrated in FIG. 1, a fresh air introduction chamber (10) is provided next to the crankcase (9), and the upstream intake passage (7) of the throttle valve (5) is connected via the fresh air introduction passage (8). The fresh air introduction chamber (10) communicates with the crankcase (9) through the throttle hole (11) facing the crankcase (9), and the fresh air introduction passage (8 By providing a check valve (29) for suppressing backflow at the passage outlet (8a) of
The fresh air (12) in the intake passage (7) on the upstream side of the throttle valve (5) includes a fresh air introduction passage (8), a check valve (29), a fresh air introduction chamber (10), and a throttle hole (11). Are introduced to the crankcase (9) through the
During reverse flow, the gas in the crankcase (9) passes through the throttle hole (11), the fresh air introduction chamber (10), the valve clearance (30) of the check valve (29), and the fresh air introduction passage (8) in this order. When the gas pressure applied to the check valve (29) exceeds a predetermined value, the check valve (29) is fully closed to prevent the reverse flow. To be
As illustrated in FIGS. 2 to 4, a passage opening (8 a) of the fresh air introduction passage (8) is provided in the fresh air introduction chamber wall (13), and a check valve (29) is provided in front of the passage outlet (8 a). ), A check valve facing wall (18) is provided in front of the check valve (29),
The check valve surrounding walls (22), (23) and (24) are led out from the peripheral edge of the check valve facing wall (18) toward the fresh air introduction chamber wall (13) to which the check valve (29) is attached. The check valve (29) is surrounded by the check valve surrounding walls (22), (23), and (24) from three sides, and the communication port (26) is provided on the other side, and the check valve facing wall (18) and The enclosure space (27) surrounded by the check valve enclosure walls (22), (23) and (24) is communicated with the outside fresh air introduction chamber (10) through the communication port (26). Engine blowby gas recirculation system.

(Invention of Claim 1)
The invention according to claim 1 has the following effects.
<Effect> The ventilation efficiency of the crankcase can be increased.
As illustrated in FIG. 1, the fresh air (12) in the upstream intake passage (7) of the throttle valve (5) includes a fresh air introduction passage (8), a check valve (29), and a fresh air introduction chamber (10). ) And the throttle hole (11) are introduced into the crankcase (9) in this order, so that the fresh air (12) is introduced into the crankcase (9) without being short-circuited to the PCV valve (3). The ventilation efficiency of the case (9) can be increased.

<Effect> It is possible to suppress oil mist from being taken into the intake passage.
As illustrated in FIG. 1, during reverse flow, the gas in the crankcase (9) is introduced into the throttle hole (11), the fresh air introduction chamber (10), the valve clearance (30) between the check valve (29), and fresh air introduction. When the gas pressure applied to the check valve (29) exceeds a predetermined value by flowing back to the intake passage (7) on the upstream side of the throttle valve (5) through the passage (8) in order, the check valve (29 ) Is fully closed to prevent backflow, and during backflow, the gas in the crankcase (9) containing oil mist expands in the process of flowing into the new introduction chamber (10) from the throttle hole (11). The oil mist condenses and separates due to the decrease in the flow velocity, and further oil is separated even in the process of passing through the valve gap (30) of the check valve (29). In the case of excess, backflow is prevented. For this reason, it is possible to suppress the oil mist from being taken into the intake passage. Thereby, problems such as sticking of the valve shaft of the throttle valve (5) due to carbon or the like contained in the oil mist can be suppressed.

<Effect> The oil mist removal suppression function during backflow is high.
As illustrated in FIGS. 2 to 4, a passage opening (8 a) of the fresh air introduction passage (8) is provided in the fresh air introduction chamber wall (13), and a check valve (29) is provided in front of the passage outlet (8 a). ) And the check valve facing wall (18) is provided in front of the check valve (29), so that the oil mist is blocked by the check valve facing wall (18) and reaches the check valve (29). Hard to do. For this reason, the oil mist removal suppression function at the time of backflow is high.

<Effect> The oil mist removal suppression function during backflow is high.
As illustrated in FIGS. 2 to 4, a check valve surrounding wall (from the peripheral edge of the check valve facing wall (18) toward the fresh air introduction chamber wall (13) to which the check valve (29) is attached. 22) (23) (24) is derived, and the check valve (29) is surrounded by check valve surrounding walls (22), (23), and (24) from three sides, and the communication port (26) is provided on the other side. The surrounding fresh air introduction chamber (10) is connected to the outer space (27) surrounded by the check valve facing wall (18) and the check valve surrounding walls (22), (23), (24) through the communication port (26). The oil mist is blocked by the check valve surrounding walls (22), (23), and (24) and hardly reaches the check valve (29). For this reason, the oil mist removal suppression function at the time of backflow is high.

(Invention of Claim 2 )
The invention according to claim 2 has the following effect in addition to the effect of the invention according to claim 1 .
<Effect> The oil mist removal suppression function during backflow is high.
As shown in FIGS. 2 to 4, engine oil that flows downward on the upper surface of the lower check valve surrounding wall (24) with the lower check valve surrounding wall (24) inclined downward toward the communication port (26). However, the engine oil condensed inside the check valve surrounding walls (22), (23) and (24) is allowed to flow downward from the communication port (26) to the lower part of the fresh air introduction chamber (10). It flows through the upper surface of the stop valve surrounding wall (24) and is quickly discharged from the communication port (26). For this reason, the oil mist removal suppression function at the time of backflow is high.

It is a mimetic diagram of an engine provided with a blowby gas recirculation device concerning an embodiment of the present invention. It is a vertical back view of the cylinder block of the engine provided with the blowby gas recirculation apparatus concerning the embodiment of the present invention. It is a principal part side view of the cylinder block of FIG. 4A is a side view of the fresh air introduction chamber and the vicinity thereof, FIG. 4B is a cross-sectional view taken along the line BB of FIG. 4A, and FIG. 4C is a cross-sectional view taken along the line CC of FIG. 4A, FIG. 4D is a side view of a modified example of the check valve facing wall and the check valve surrounding wall, and FIG. 4E is FIG. It is the EE sectional view taken on the line of). It is a side view of an engine provided with a blowby gas recirculation device concerning an embodiment of the present invention. FIG. 6 is a plan view of the engine of FIG. 5.

  FIGS. 1-6 is a figure explaining the blowby gas recirculation apparatus of the engine which concerns on embodiment of this invention, and this embodiment demonstrates a vertical in-line multicylinder gas engine.

As shown in FIGS. 5 and 6, this engine has a cylinder head (1) assembled to the top of a cylinder block (35), a head cover (2) assembled to the top of the cylinder head (1), and a cylinder block (35). The oil pan (36) is assembled to the lower part of the cylinder, the gear case (31) is assembled to the front part of the cylinder block (35), the engine cooling fan (37) is arranged at the front part of the gear case (31), and the cylinder block (35) A flywheel (38) is arranged at the rear.
The upper half part of the cylinder block (35) is a cylinder part (39), and the lower half part is a crankcase (9).
An intake manifold (40) is arranged on one side of the cylinder head (1), a throttle body (42) is attached to the front of the parent pipe (41) of the intake manifold (40), and the front of the throttle body (42) is attached. A gas mixer (43) is attached. As shown in FIG. 1, an air cleaner (44) communicates with the gas mixer (43).

  As shown in FIG. 1, a PCV valve (3) is attached to a head cover (2) attached to a cylinder head (1), and this PCV valve (3) is connected to a throttle valve (5) via a blow-by gas passage (4). The downstream intake passage (6) communicates, and the upstream intake passage (7) of the throttle valve (5) communicates with the crankcase (9) via the fresh air introduction passage (8). The PCV valve is an abbreviation for positive crankcase ventilation.

  As shown in FIG. 1, a fresh air introduction chamber (10) is provided next to the crankcase (9), and the upstream intake passage (7) of the throttle valve (5) is newly introduced via the fresh air introduction passage (8). The fresh air introduction chamber (10) communicates with the crankcase (9) through the throttle hole (11) facing the crankcase (9), and communicates with the fresh air introduction passage (8). A check valve (29) for suppressing backflow is provided at the passage outlet (8a).

  Thus, the fresh air (12) in the upstream intake passage (7) of the throttle valve (5) is introduced into the fresh air introduction passage (8), the check valve (29), the fresh air introduction chamber (10), and the throttle hole ( 11) and the crankcase (9). The crankcase (9) is ventilated with fresh air (12), blow-by gas (45) floats to the head cover (2) through the push rod chamber, and passes from the PCV valve (3) through the blow-by gas passage (4). Thus, the refrigerant is returned to the intake passage (6) on the downstream side of the throttle valve (5) and recombusted in the combustion chamber (46).

During reverse flow, the gas in the crankcase (9) passes through the throttle hole (11), the fresh air introduction chamber (10), the valve clearance (30) of the check valve (29), and the fresh air introduction passage (8) in this order. When the gas pressure applied to the check valve (29) exceeds a predetermined value, the check valve (29) is fully closed to prevent the reverse flow. It has come to be.
When the load is high, the amount of blow-by gas increases. However, since the throttle valve (5) has a large opening, the negative pressure in the downstream intake passage (6) is low (becomes closer to atmospheric pressure). The above-described backflow may occur in time.

  As shown in FIGS. 2 to 4, a fresh air introduction pipe (14) is attached to the fresh air introduction chamber wall (13), and a fresh air relay pipe (15) is connected to a pipe inlet portion (15) of the fresh air introduction pipe (14). 16) is connected to the pipe end portion (16a), and the fresh air relay pipe (16) and the fresh air introduction pipe (14) constitute a fresh air introduction passage (8), and the fresh air introduction pipe (14) pipe. The outlet (17) is a passage outlet (8a) of the fresh air introduction passage (8), a check valve (29) is provided in front of the passage outlet (8a), and a pipe outlet is provided in front of the check valve (29). An opposing wall (18) is provided. The check valve (29) is a reed valve.

  As shown in FIGS. 2 to 4, toward the fresh air introduction chamber wall (13) to which the check valve (29) is attached, from the peripheral portion of the check valve facing wall (18), the check valve surrounding wall (22 ) (23) (24) is led out by bending, and the check valve (29) is surrounded by check valve surrounding walls (22), (23), (24) from three sides, and the communication port (26 ) And a fresh air introduction chamber outside the communication space (27) through the surrounding space (27) surrounded by the check valve facing wall (18) and the check valve surrounding walls (22), (23), (24). It communicates with (10).

  As shown in FIGS. 2 to 4, the lower check valve surrounding wall (24) is inclined downward toward the communication port (26), and the engine oil flowing on the upper surface of the lower check valve surrounding wall (24) In addition, it flows down from the communication port (26) to the lower part of the fresh air introduction chamber (10).

  4 (D) and 4 (E) show a modified example of the check valve facing wall (18) and the check valve surrounding walls (22), (23), and (24). It has a curved shape.

(1) Cylinder head
(2) Head cover
(3) PCV valve
(4) Blow-by gas passage
(5) Throttle valve
(6) Downstream intake passage
(7) Upstream intake passage
(8) Fresh air passage
(8a) Passage exit
(9) Crankcase
(10) Fresh air introduction room
(11) Aperture hole
(12) Fresh
(13) Fresh air introduction room wall
(18) Check valve facing wall
(22) Upper check valve wall
(23) Front check valve wall
(24) Lower check valve wall
(26) Communication port
(27) Go space
(29) Check valve
(30) Clearance

Claims (2)

A PCV valve (3) is attached to a head cover (2) attached to the cylinder head (1), and the PCV valve (3) is connected to a downstream side intake passage (6) of the throttle valve (5) via a blow-by gas passage (4). In the blow-by gas recirculation device for the engine, the upstream intake passage (7) of the throttle valve (5) communicates with the crankcase (9) through the fresh air introduction passage (8).
A fresh air introduction chamber (10) is provided next to the crankcase (9), and the upstream intake passage (7) of the throttle valve (5) is connected to the fresh air introduction chamber (10) via the fresh air introduction passage (8). The fresh air introduction chamber (10) communicates with the crankcase (9) through a throttle hole (11) facing the crankcase (9), and communicates with the passage outlet (8a) of the fresh air introduction passage (8). By providing a check valve (29) that suppresses backflow,
The fresh air (12) in the intake passage (7) on the upstream side of the throttle valve (5) includes a fresh air introduction passage (8), a check valve (29), a fresh air introduction chamber (10), and a throttle hole (11). Are introduced to the crankcase (9) through the
During reverse flow, the gas in the crankcase (9) passes through the throttle hole (11), the fresh air introduction chamber (10), the valve clearance (30) of the check valve (29), and the fresh air introduction passage (8) in this order. When the gas pressure applied to the check valve (29) exceeds a predetermined value, the check valve (29) is fully closed to prevent the reverse flow. To be
The fresh air introduction chamber wall (13) is provided with a passage outlet (8a) of the fresh air introduction passage (8), a check valve (29) is provided in front of the passage outlet (8a), and the check valve (29) A check valve facing wall (18) is provided in front of
The check valve surrounding walls (22), (23) and (24) are led out from the peripheral edge of the check valve facing wall (18) toward the fresh air introduction chamber wall (13) to which the check valve (29) is attached. The check valve (29) is surrounded by the check valve surrounding walls (22), (23), and (24) from three sides, and the communication port (26) is provided on the other side, and the check valve facing wall (18) and The enclosure space (27) surrounded by the check valve enclosure walls (22), (23) and (24) is communicated with the outside fresh air introduction chamber (10) through the communication port (26). Engine blowby gas recirculation system. In the engine blowby gas recirculation device according to claim 1 ,
The lower check valve wall (24) is inclined downward toward the communication port (26), and the engine oil flowing on the upper surface of the lower check valve wall (24) is introduced into the fresh air from the communication port (26). A blow-by gas recirculation device for an engine characterized by flowing down to the lower part of the chamber (10).

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