JPH04237859A - Exhaust gas discharge structure for internal combustion engine - Google Patents

Abstract

PURPOSE:To discharge exhaust gas being exhausted out of an internal combustion engine with plural combustion chambers, to an intake collecting part at the downstream side from a throttle valve in an intake passage, mixing the discharge exhaust gas with intake air uniformly, while feeding it to each combustion chamber, and preventing a solid component in the exhaust gas from sticking to the backside of the throttle valve. CONSTITUTION:An upstream end of each branch intake passage 5 connected to each combustion chamber 2 of a multicylinder internal combustion engine 1 is opened to an intake air collecting part 9, while a main intake opening part 10 is formed in an end of the intake air collecting part 9 situated in front of the arraying direction of the branch intake passages 5, and a throttle valve 14 is installed in a throttle valve body 13 being interconnected to this main intake opening part 10 free of opening or closing, and an exhaust gas recirculation(EGR) pipe 20 is set up at a nearby spot of the second branch intake passage 5b counting from the branch intake passages 5 nearer to the main intake opening part 10, then an EGR discharge opening part 21 of the EGR discharge pipe 20 is opened to the center of a cross section of the intake air collecting part 9.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an exhaust gas recirculation system (hereinafter referred to as EGR) in a multi-cylinder internal combustion engine having a plurality of combustion chambers.
The exhaust gas of the internal combustion engine, such as EGR gas or blow-by gas in the crank chamber, supplied to the intake system from a The present invention relates to an exhaust gas discharge structure for an internal combustion engine that prevents solid content such as organic components or inorganic components from adhering to the outer peripheral edge of a throttle valve.

0002

[Prior Art and Problems to be Solved] In a conventional multi-cylinder internal combustion engine that has a plurality of combustion chambers and is equipped with an EGR device, as described in Japanese Utility Model Application No. 59-159767, EGR gas is In order to uniformly mix and evenly distribute the EG to each combustion chamber, the EG
The R gas discharge port was opened.

However, when the opening degree of the throttle valve is reduced, the intake air that passes through the gap between the front edge of the throttle valve and the wall of the main intake passage flows while sucking out the intake air from the back side of the throttle valve.
A part of the EGR gas flows back toward the center of the back surface of the throttle valve to fill the sucked-out space, so that solid components in the EGR gas may adhere to the back surface of the throttle valve. In particular, in an internal combustion engine such as that disclosed in Japanese Utility Model Application Publication No. 59-159767, in which the EGR gas discharge port is opened toward the throttle valve, the above-mentioned disadvantageous phenomenon appears even more clearly.

0004

[Means for Solving the Problems and Effects] The present invention relates to an improvement in the exhaust gas discharge structure of an internal combustion engine that overcomes the above-mentioned difficulties, and includes branch intake passages arranged in rows in each of a plurality of combustion chambers. In an internal combustion engine in which a throttle valve is provided in a main intake passage connected to one side end of the intake passage, an intake passage is connected to the intake passage through an intake passage, and a throttle valve is disposed in a main intake passage connected to one side end of the intake passage. An exhaust gas discharge pipe is provided protruding from a substantially central portion of the exhaust gas discharge pipe located closer to the throttle valve, and the tip of the exhaust gas discharge pipe is opened at a substantially central portion of the cross section of the intake collecting portion, The center of the cross-section of the main intake passage or the cross-section of the intake collecting section, located between the throttle valve and the exhaust gas discharge pipe, and located on the side where the leading edge furthest from the center of rotation faces the upstream direction. It is characterized in that a partition wall portion protruding toward the center is provided.

[0005] As described above, the present invention provides an exhaust gas discharge pipe that is modified so as to be located closer to the throttle valve than the approximate center of the upstream end of the branch intake passage in the arrangement direction of the upstream end of the branch intake passage. Since the tip of the pipe is opened at approximately the center of the cross section of the intake air collecting section, the exhaust gas discharged from the exhaust gas discharge pipe to the collecting chamber passes through the main intake passage and enters the intake air. It is uniformly mixed with the intake air that has flowed into the collecting section, and is evenly supplied into each of the combustion chambers through each of the branched intake passages.

Further, in the present invention, the leading edge of the throttle valve farthest from the center of rotation is located on the side facing upstream and between the throttle valve and the exhaust gas discharge pipe, and the main intake passage is located between the throttle valve and the exhaust gas discharge pipe. Since the partition wall protrudes toward the center of the cross-section of the or the center of the cross-section of the intake collecting section, when the opening of the throttle valve is small, the air passes through the gap between the tip edge of the throttle valve and the wall of the main intake passage. The intake air flows along the wall surface of the main intake passage, flows into the intake air gathering part while sucking out the intake air near the back surface of the throttle valve, and is reversed within the intake air collecting part and flows toward the back surface of the throttle valve along the wall surface of the main intake passage. Even if you try to reverse the flow,
This backflow is prevented by the partition wall portion, and solid components in the exhaust gas mixed with the intake air in the intake air gathering portion are prevented from adhering to the back surface of the throttle valve, and the throttle valve can be opened and closed smoothly, and the driver Improves performance.

[0007]

[Embodiment] An embodiment of the present invention illustrated in FIGS. 1 to 4 will be described below. The internal combustion engine 1 of the present embodiment is an in-line five-cylinder, four-stroke internal combustion engine, and is mounted on an automobile (not shown) with its crankshaft (not shown) oriented in the longitudinal direction of the vehicle body.

A branch intake passage 5 of the intake manifold 4 is connected to the opening of the intake port 3 connected to each combustion chamber 2 of the internal combustion engine 1.
The downstream end of each branch intake passage 5 is further divided vertically into a primary intake passage 6 and a secondary intake passage 7, and a bypass valve 8 is interposed in the secondary intake passage 7 so as to be openable and closable. ,
When the internal combustion engine 1 is rotating at a low speed, the bypass valve 8 is closed and the intake air passes only through the primary intake passage 6. When the internal combustion engine 1 is rotating at a high speed, the bypass valve 8 is opened and the intake air passes only through the primary intake passage 6. It passes through the primary intake passage 6 and the secondary intake passage 7,
It is designed to be sucked into the combustion chamber 2.

[0009] Further, an intake collecting section 9 is connected to the upstream end of the branched intake passage 5, and a main intake passage 10 is formed at the front end of the intake collecting part 9. The gasket 11 is connected to an air cleaner (not shown), and the gasket 11 has a distal end edge 15a of the throttle valve 14 pivoted to the throttle valve body 13 so as to be openable and closable, and protrudes from the same side as the upstream end edge 15a. The partition wall portion 12 protrudes and is formed with an air bypass opening 18 that communicates with an air bypass passage 17 described later.

Furthermore, the boundary between the inner circumferential wall of the intake air gathering portion 9 and the main intake passage 10 is connected by a smooth curved surface 16. Further, an air bypass passage 17 is formed on the side wall of the intake air collecting portion 9 to control the amount of air flowing by bypassing the throttle valve 14, thereby adjusting the idle rotation.

Furthermore, a fuel injection valve 19 is provided at the connection between the intake manifold 4 and the branched intake passage 5, and fuel is injected into the intake manifold 4 from the fuel injection valve 19 at an appropriate timing depending on the operating conditions. It is designed to be sprayed. Moreover, it is located near the second branch intake passage 5b, and the EGR discharge pipe 20 passes through the intake collecting section 9 from above downward, and the EGR discharge opening 21 at the tip thereof has a cross section of the intake collecting section 9. It is opened in the center.

Since the embodiment shown in FIGS. 1 to 4 is configured as described above, when the internal combustion engine 1 is in operation, air filtered by an air cleaner (not shown) is taken in through the throttle valve body 13. The fuel flows into the gathering part 9, reaches each intake port 3 via the branch intake passage 5, and is connected to the fuel injection valve 1.
It is mixed with the fuel injected from 9 and supplied to each combustion chamber 2. In an operating range that requires EGR, EGR gas, which is partially extracted from the exhaust gas discharged from the combustion chamber 2 of the internal combustion engine 1, is sent to the EGR discharge pipe 20 and passed through the EGR discharge opening 21 to the intake collecting section 9. discharged inside.

Furthermore, in the EGR operating state, the secondary intake passage 7
The bypass valve 8 inside is closed, and the throttle valve 14 is closed.
When the opening degree of is large, air filtered by an air cleaner (not shown) flows into the intake collecting section 9 from the main intake passage 10, and the air enters the intake collecting part 9 near the second branch intake passage 5b in the intake collecting part 9. The EGR gas is uniformly mixed with the EGR gas discharged at the center of the cross section of 9, and is supplied to each combustion chamber 2 through the primary intake passage 6 of each branch intake passage 5. Proper combustion conditions can be obtained.

Furthermore, in the EGR operating state, the throttle valve 1
Even when the opening degree of the throttle valve 4 is narrowed down to a small value, as shown in FIG. The throttle valve 1 is deflected downward in FIG.
4, the intake air swirls counterclockwise in the intake air gathering part 9, and this swirling flow generates a stagnation part 22 in the center of the intake air collecting part 9, and this stagnation part 22 to EGR
Since the EGR discharge opening 21 of the discharge pipe 20 is open, EGR gas flows into this stagnation part 22 and is uniformly mixed for a relatively long time before being discharged into one of each branch intake passage 5.
It is supplied into the combustion chamber 2 via the secondary intake passage 6 and the intake port 3. Since the curved surface 16 is formed at the boundary between the main intake passage 10 and the inner circumferential wall surface of the intake air gathering portion 9,
The counterclockwise swirling flow described above can be generated reliably and stably. The amount of intake air when the throttle valve is closed is such that bypass air from the air bypass passage 17 is smoothly introduced when the intake air gathers at the intake air gathering portion 9.

[0015] In this way, regardless of the opening degree of the throttle valve 14, the EGR gas can be uniformly mixed with the intake air and evenly supplied to each combustion chamber 2.

Furthermore, in the EGR operation state in which the throttle valve 14 is throttled, the intake air that has passed near the tip edge 15a of the throttle valve 14 on the upstream side of the passage in the throttle valve body 13 is blocked by the protruding partition wall 12. Since it flows downward along the back surface of the throttle valve 14, even if the intake air in the intake air collecting section 9 temporarily flows toward the throttle valve 14 due to intake pulsation, the EGR gas will not flow toward the throttle valve 14. This prevents solid components in the EGR gas from adhering to the back surface of the throttle valve 14, allowing the throttle valve 14 to open and close smoothly, resulting in good drivability. Note that in the above embodiments, the exhaust gas was EGR gas, but blow-by gas may also be used.

[0017]

[Brief explanation of the drawing]

FIG. 1 is a front view of an internal combustion engine showing a cross section of an embodiment of an exhaust gas discharge structure for an internal combustion engine according to the present invention.

FIG. 2 is a plan view thereof.

FIG. 3 is a longitudinal side view showing the flow and mixing state of intake air and EGR.

FIG. 4 is a front view of the gasket of the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 2... Combustion chamber, 3... Intake port, 4... Intake manifold, 5... Branch intake passage, 6... Primary intake passage, 7
...Secondary intake passage, 8...Bypass valve, 9...Intake gathering part, 1
0...Main intake passage, 11...Gasket, 12...Protruding partition part, 13... Throttle valve body, 14... Throttle valve, 15... Tip edge, 1
6... Curved surface, 17... Air bypass passage, 18... Air bypass opening, 19... Fuel injection valve, 20... EGR discharge pipe, 2
1...EGR discharge opening, 22...Stagnation part.

Claims (1)

[Claims] 1. An intake air collecting section is connected to a plurality of combustion chambers through branch intake passages arranged in a row, and a throttle valve is disposed in a main intake passage connected to one side end of the intake air collecting section. In the internal combustion engine, an exhaust gas discharge pipe is provided protruding from a substantially central portion of the upstream end of the branch intake passage in the arrangement direction of the branch intake passage in the intake collecting section, and is located closer to the throttle valve, and a distal end of the exhaust gas discharge pipe is provided. is opened at approximately the center of the cross-sectional area of the intake collecting section, and the end edge furthest from the center of rotation of the throttle valve faces the upstream direction, and is located between the throttle valve and the exhaust gas discharge pipe. An exhaust gas discharge structure for an internal combustion engine, characterized in that a partition is provided between the main intake passages and the partition wall protruding toward the center of the cross section of the main intake passage or the center of the cross section of the intake collecting section.