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US-20260125996-A1 - BLOW-BY GAS RECIRCULATION DEVICE

US20260125996A1US 20260125996 A1US20260125996 A1US 20260125996A1US-20260125996-A1

Abstract

A blow-by gas recirculation device includes a first passage, a second passage, and a flow control valve unit. The first passage provides communication between a crank chamber of an internal combustion engine and a first region of an intake system downstream of a throttle valve, and recirculates blow-by gas to the intake system. The second passage provides communication between the crank chamber and a second region of the intake system upstream of the throttle valve. The flow control valve unit is disposed in the first passage to vary a passage area according to the first region pressure and the crank chamber pressure and includes a first valve that opens when the crank chamber pressure exceeds the first region pressure by a predetermined amount or more and a second valve that opens when the first region pressure exceeds the crank chamber pressure by a predetermined amount or more.

Inventors

  • Hidenori ANZAI

Assignees

  • Subaru Corporation

Dates

Publication Date
20260507
Application Date
20251023
Priority Date
20241101

Claims (4)

  1. 1 . A blow-by gas recirculation device comprising: a first passage configured to provide communication between a crank chamber of an internal combustion engine and a first region of an intake system, the first region being located downstream of a throttle valve of the intake system, and configured to recirculate blow-by gas to the intake system; a second passage configured to provide communication between the crank chamber and a second region of the intake system, the second region being located upstream of the throttle valve; and a flow control valve unit disposed in the first passage and configured to vary a passage area according to a pressure in the first region and a pressure in the crank chamber, wherein the flow control valve unit comprises a first valve configured to open when the pressure in the crank chamber exceeds the pressure in the first region by a predetermined amount or more, and a second valve configured to open when the pressure in the first region exceeds the pressure in the crank chamber by a predetermined amount or more.
  2. 2 . The blow-by gas recirculation device according to claim 1 , wherein a valve body of a one of the first valve and the second valve comprises another one of the first valve and the second valve.
  3. 3 . The blow-by gas recirculation device according to claim 2 , wherein the valve body of the one of the first valve and the second valve has an internal hole, and the another of the first valve and the second valve varies an opening area of the internal hole.
  4. 4 . The blow-by gas recirculation device according to claim 1 , wherein the second valve is configured to close when a difference obtained by subtracting the pressure in the crank chamber from the pressure in the first region exceeds a predetermined threshold value.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority from Japanese Patent Application No. 2024-192584 filed on Nov. 1, 2024, the entire contents of which are hereby incorporated by reference. BACKGROUND The disclosure relates to a blow-by gas recirculation device. Conventionally, there has been known a technique in which blow-by gas leaking from a combustion chamber of an internal combustion engine into a crankcase is recirculated to an intake system of the internal combustion engine and used again as intake air. For example, Japanese Unexamined Patent Application Publication (JP-A) No. 2014-163347 discloses a configuration of an internal combustion engine including a first passage that provides communication between an inner chamber in which blow-by gas accumulates and a downstream side of a throttle valve in an intake passage, a second passage that provides communication between the inner chamber and an upstream side of a supercharger in the intake passage, and a PCV valve disposed to open and close the first passage. SUMMARY An aspect of the disclosure provides a blow-by gas recirculation device including a first passage, a second passage, and a flow control valve unit. The first passage is configured to provide communication between a crank chamber of an internal combustion engine and a first region of an intake system, the first region being located downstream of a throttle valve of the intake system, and configured to recirculate blow-by gas to the intake system. The second passage is configured to provide communication between the crank chamber and a second region of the intake system, the second region being located upstream of the throttle valve. The flow control valve unit is disposed in the first passage and configured to vary a passage area according to a pressure in the first region and a pressure in the crank chamber. The flow control valve unit includes a first valve configured to open when the pressure in the crank chamber exceeds the pressure in the first region by a predetermined amount or more and a second valve configured to open when the pressure in the first region exceeds the pressure in the crank chamber by a predetermined amount or more. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate an embodiment and, together with the specification, serve to describe the principles of the disclosure. FIG. 1 is a schematic diagram illustrating a configuration example of an internal combustion engine including a blow-by gas recirculation device according to an embodiment of the disclosure. FIG. 2 is a schematic diagram illustrating a configuration example of a flow control valve unit of the blow-by gas recirculation device according to the embodiment of the disclosure. FIG. 3 is an explanatory diagram illustrating an operation of the flow control valve unit during a low-load operation of the internal combustion engine. FIG. 4 is an explanatory diagram illustrating a flow of blow-by gas during low-load operation of the internal combustion engine. FIG. 5 is an explanatory diagram illustrating an operation of the flow control valve unit during a medium-load operation of the internal combustion engine. FIG. 6 is an explanatory diagram illustrating a flow of the blow-by gas during medium-load operation of the internal combustion engine. FIG. 7 is an explanatory diagram illustrating an operation of the flow control valve unit during full boost of the internal combustion engine. FIG. 8 is an explanatory diagram illustrating a flow of the blow-by gas during full boost of the internal combustion engine. FIG. 9 is a schematic view illustrating a modification of the flow control valve unit of the blow-by gas recirculation device according to the embodiment of the disclosure. DETAILED DESCRIPTION The PCV valve disclosed in JP-A No. 2014-163347 has a configuration of a mechanical (differential-pressure-operated) flow control valve in which a valve body, which is pressed against a valve seat by an elastic urging force, is displaced in a direction away from the valve seat against the elastic urging force by pressure of the blow-by gas, thereby increasing or decreasing a flow rate of the blow-by gas flowing through the first passage. When a mechanical flow control valve is used, during a low-load operation of the internal combustion engine in which supercharging is not substantially performed, the pressure downstream of the throttle valve becomes a negative pressure, and the flow control valve opens, so that fresh air can be introduced into the inner chamber (crank chamber) via the second passage. Therefore, the blow-by gas can be discharged together with the fresh air via the first passage, and fuel, moisture, and the like contained in the blow-by gas can be scavenged. However, when supercharging of the internal combus