JP3147571B2 - Intake device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an intake device for an internal combustion engine.

[0002]

2. Description of the Related Art In an internal combustion engine mounted on an automobile or the like, EGR gas, which is a part of exhaust gas, is recirculated to an intake passage to reduce the amount of NOx in the exhaust gas. Variations in the amount of EGR gas cause an increase in engine idle vibration and the like.

[0003] As a conventional intake device for an internal combustion engine, for example, there is one as shown in FIG.
Publication No.).

[0004] To explain this, reference numeral 31 denotes an intake manifold which defines an intake passage 32 of an engine.
0 is a throttle chamber in which a throttle valve 33 is interposed, 34
Is an auxiliary air passage for guiding auxiliary air bypassing the throttle valve 3,
An exhaust gas recirculation passage 36 recirculates the EGR gas to the intake passage 2.

The exhaust gas recirculation passage 36 opens downstream of the opening of the auxiliary air passage 34 of the intake passage 32, and the auxiliary air and the EGR as shown by arrows in FIG. Gases are merged and distributed to each cylinder.

[0006]

However, in such a conventional intake device for an internal combustion engine, since the auxiliary air passage 34 is formed in parallel with the intake passage 32, the auxiliary air flowing into the intake passage 32 is not provided. The air merges with the main flow of the intake air passing through the throttle valve 33 without being greatly disturbed, and the air is not sufficiently mixed with the EGR gas that merges with the main flow, so that the amount of the EGR gas distributed to each cylinder varies, and the Problems are conceivable in that the drivability deteriorates and the exhaust gas purification performance is adversely affected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to uniformly distribute EGR gas to each cylinder in an intake device of an internal combustion engine.

[0008]

SUMMARY OF THE INVENTION The present invention relates to an intake system for an internal combustion engine that introduces auxiliary air into an intake passage downstream of an intake throttle valve and recirculates EGR gas into the intake passage. The auxiliary air port to be formed is formed so as to face the main flow of the intake air in the intake passage, and the EGR port for causing the EGR gas to flow into the intake passage is located at the intersection of the flow path center line of the auxiliary air port and the extended surface of the intake passage inner wall surface. It is located immediately downstream.

[0009]

In the intake passage, auxiliary air flows in from the auxiliary air port and EGR gas flows in from the EGR port, and these are distributed to each cylinder while mixing with the fresh intake air that has passed through the throttle valve.

With the structure in which the auxiliary air port is opened opposite to the main flow of the intake fresh air passing through the throttle valve, the auxiliary air ejected from the auxiliary air port to the intake passage and the intake fresh air passing through the throttle valve collide with each other. However, a turbulent flow is generated in which the auxiliary air and the fresh air are mixed irregularly.

When the EGR port is opened immediately downstream of the intersection of the flow path center line of the auxiliary air port and the extended surface of the inner wall of the intake passage, the EGR gas flowing from the EGR port into the intake passage is The gas is jetted into the turbulent flow of the intake air, and the mixing with the intake air is promoted. As a result, it is possible to suppress a variation in the amount of EGR gas distributed to each cylinder.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, an intake throttle valve 3 is provided in an intake passage 2 of the engine, and the throttle valve 3 rotates about a shaft 9 in conjunction with an accelerator pedal (not shown).
The intake air amount of the engine is adjusted.

An auxiliary air passage 4 for guiding auxiliary air bypassing the throttle valve 3 is connected to the intake passage 2, and an auxiliary air amount control valve 5 is provided in the auxiliary air passage 4. The auxiliary air amount control valve 5 is duty-controlled during a valve opening time period of 0 to 100%. When the throttle valve 3 is fully closed, the intake air amount is adjusted in accordance with the engine operating state, so that the The idle speed is feedback-controlled to a target value. The auxiliary air amount control valve 5 may be configured to be driven by a step motor.

An exhaust gas recirculation passage 6 connecting the exhaust passage of the engine and the intake passage 2 is provided. An exhaust gas recirculation control valve (not shown) is interposed in the exhaust gas recirculation passage 6, and EGR gas, which is a part of the exhaust gas, is recirculated to the intake passage 2 according to engine operating conditions. By recirculating EGR gas to each cylinder,
Lower the oxygen concentration in the cylinder, lower the fuel combustion temperature
Suppress the generation of x.

A blower gas passage 7 for returning the blower gas to the intake passage 2 is provided. The blow-by gas blown from the combustion chamber to the crank chamber or the valve operating chamber on the cylinder head is returned to the intake passage 2 through the blower gas passage 7, thereby preventing unburned HC from being taken out together with the blower gas.

In FIG. 1, reference numeral 1 denotes an intake manifold defining an intake passage 2, which is connected to a cylinder head of the engine. The intake manifold 1 has a branch section 14 communicating with each cylinder, a collector section 13 for distributing intake air to each branch section 14, and a straight cylindrical throttle chamber section 11 in which the throttle valve 3 is interposed.

The intake manifold 1 has a mixer section 12 connecting a throttle chamber section 11 and a collector section 13. The mixer section 12 is formed in a cylindrical shape that is connected to the throttle chamber section 11 and the collector section 13 at a predetermined angle. Thus, the intake passage 2 defined by the throttle chamber section 11, the mixer section 12, and the collector section 13 is bent in a crank shape.

The intake manifold 1 has an auxiliary air hole 15 which is an inlet of the auxiliary air passage 4. The auxiliary air port 15 opens toward the upstream side of the intake passage 2 so as to face the main flow of the intake air flowing through the intake passage 2. The auxiliary air port 15 is located at the outside of the curved portion at the upstream end of the mixer section 12 and is opened, and its flow path center line O ₆
Are arranged in parallel with the center line of the flow path of the throttle chamber section 11. The auxiliary air port 15 is arranged such that its flow path center line O ₆ has an angle larger than 90 ° with respect to the flow path center line of the throttle chamber section 11, so that the main flow of intake air flowing through the intake passage 2 is Oppose.

The intake manifold 1 has an EGR port 16 which is an inlet of the exhaust gas recirculation passage 6. EGR
The port 16 is opened immediately downstream of an intersection P between the flow path center line O ₆ of the auxiliary air port 15 and the extension surface of the intake passage inner wall surface 20.

The partition wall 21 that separates the auxiliary air port 15 of the intake manifold 1 from the intake passage 2 has a cross section facing upstream of the intake passage 2 at a position located downstream of the opening end of the auxiliary air port 15. It is formed in a wedge shape protruding at an acute angle.

The blower gas passage 7 is connected to the upstream part of the collector part 13 alongside the branch part 14.

Next, the operation will be described.

In the mixer section 12 of the intake passage 2, auxiliary air flows in from the auxiliary air port 15 and the EGR
The EGR gas flows in from the port 16, flows into the collector 13 while being mixed with the fresh air that has passed through the throttle valve 3, and is distributed to each branch 14.

A structure in which the auxiliary air port 15 is opened so as to face the main flow of the intake fresh air passing through the throttle valve 3 enables the auxiliary air ejected from the auxiliary air port 15 to the intake passage 2 and the throttle valve 3.
The intake fresh air that has passed through the air collide with each other, and a turbulent flow occurs while the minute lump of the auxiliary air and the minute lump of the intake fresh air mix irregularly.

The EGR port 16 is opened immediately downstream of an intersection P between the flow path center line O ₆ of the auxiliary air port 15 and the extended surface of the inner wall surface 20 of the intake passage to open the EGR port 16.
The EGR gas flowing into the intake passage 2 from the GR port 16 is jetted into the turbulent flow of the intake air, and the mixing with the intake air is promoted.

At the time of idling operation in which the opening of the throttle valve 3 is small,
Although the ratio of the EGR gas recirculation amount to the intake air amount of the engine increases, the auxiliary air amount to the intake fresh air amount passing through the throttle valve 3 also increases, and turbulence generated in the intake air flow immediately upstream of the EGR port 16. The power of the flow is increased, and the mixing of the EGR gas and the intake air is promoted.

In this way, while the intake air passes through the mixer section 12 and flows into the collector section 13, mixing with the EGR gas is sufficiently performed, and the EGR gas is distributed to the respective branch sections 14 at an equal ratio. can do. As a result, it is possible to prevent the distribution of the EGR gas to each of the branch portions 14 from being biased, and to suppress the occurrence of variation in the combustibility of each cylinder, thereby reducing the engine vibration.

The blower gas passage 7 is connected to the collector 1
3, the blower gas amount distributed to each branch portion 14 has some variation, but the ratio of the blower gas recirculation amount to the intake air amount of the engine is extremely small. Has little effect on flammability.

The partition 21 that separates the auxiliary air port 15 from the intake passage 2 has a cross section protruding at an acute angle toward the upstream side of the intake passage 2 at a position downstream of the opening end of the auxiliary air port 15. By being formed in a wedge shape,
EGR gas flowing into the intake passage 2 from the EGR port 16 is suppressed from flowing over the partition 21 and flowing into the auxiliary air port 15, and carbon deposits and the like contained in the EGR gas adhere to the auxiliary air amount control valve 5 and the like. Thus, it is possible to prevent the operability from being deteriorated.

[0031]

As described above, the present invention introduces auxiliary air into the intake passage downstream of the intake throttle valve and recirculates EGR gas into the intake passage. An auxiliary air port to be formed is formed so as to face the main flow of intake air in the intake passage,
The EGR port through which the EGR gas flows into the intake passage is opened immediately downstream of the intersection of the flow path center line of the auxiliary air port and the extension of the inner wall surface of the intake passage.
The R gas is ejected into the turbulence of the intake air generated by the auxiliary air, and the mixing with the intake air is promoted, so that the amount of the EGR gas distributed to each cylinder can be made uniform.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an intake device showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an intake device showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intake manifold 2 Intake passage 3 Throttle valve 4 Auxiliary air passage 5 Auxiliary air amount control valve 6 Exhaust recirculation passage 11 Throttle chamber part 12 Mixer part 13 Collector part 14 Branch part 15 Auxiliary air port 16 EGR port 20 Intake passage inner wall surface

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02M 25/07 580 F02M 23/04 F02M 35/10 311 F02M 69/32

Claims (1)

(57) [Claims] An intake device for an internal combustion engine that introduces auxiliary air into an intake passage downstream of an intake throttle valve and recirculates EGR gas into the intake passage has an auxiliary air port through which auxiliary air flows into the intake passage. An EGR port formed so as to face the main flow of the intake air and allowing the EGR gas to flow into the intake passage is located at a position immediately downstream of an intersection between a flow path center line of the auxiliary air port and an extension surface of the inner wall surface of the intake passage. An intake device for an internal combustion engine, comprising: