JPH07189643A - Intake device for internal combustion engine - Google Patents

Abstract

PURPOSE:To solve over cumulation of condensate in a sump part so as to prevent deterioration of driving property by arranging a blowoff pipe for EGR gas above the condensate sump part of a surge tank inner bottom part. CONSTITUTION:Blow-by gas which is sucked from a blow-by gas blowoff port 20 into a surge tank 11 is sucked into each cylinder through intake pipes 13, and a part of oil, moisture, and the like in gas condensates in the surge tank 11, and falls down on the sump part 23 of an inner bottom part. Since a blowoff pipe 28 for EGR gas is arranged upward the sump part 23 and high temperature EGR gas flows to the blowoff pipe 28, condensate of the sump part 23 is heated by radiating heat from the surface of the pipe 28. Gasification of moisture in condensate is promoted, and it is sucked into each cylinder together with intake. Oil is heated, its viscosity is reduced, and its fluidity is improved. Oil flows from the small hole 24 of the sump part 23 easily, and sucked into each cylinder. Oil is burnt in a combustion chamber and discharged together with exhaust gas.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art The intake air of an internal combustion engine is distributed and taken into each cylinder from a surge tank provided in the middle of an intake system via an intake pipe line connected to the surge tank.

A blow-by gas passage for guiding blow-by gas of the engine is connected to the surge tank, and the blow-by gas is sucked and re-combusted together with the intake air. However, oil mist (blow-by oil) and water in the blow-by gas are removed. It gradually adheres to the wall of the surge tank, condenses, drops on the inner bottom of the surge tank, and accumulates.

For this reason, a condensate pool is formed on the inner bottom of the surge tank at a position above the intake conduit, and a small hole for communicating the pool with the intake conduit is formed so that the condensate can be discharged from the engine. There is a device in which it is sucked in (see JP-A-63-154813, etc.).

[0005]

However, in this case, at low temperature, the fluidity of the condensate containing the oil is lowered, so that the outflow property from the small holes is deteriorated.

Therefore, the condensed liquid may be excessively accumulated in the accumulation portion, and there is a concern that the drivability may be deteriorated when a large amount of the accumulated condensed liquid flows into the engine at one time.

The present invention aims to solve such problems.

[0008]

SUMMARY OF THE INVENTION The present invention relates to an internal combustion engine in which a surge tank provided in an intake system is connected to each cylinder via an intake pipe, and the surge tank is provided with a blow-by gas passage from the engine and an exhaust system. EGR passages are connected to each other, and a reservoir for condensate such as oil is formed above the intake pipe at the inner bottom of the surge tank, and the reservoir for the condensate is introduced through a small hole. And a pipe for blowing out EGR gas from the EGR passage is arranged above the pool of the condensate.

[0009]

Therefore, when the high temperature EGR gas passes through the EGR blow-out pipe arranged above the condensate pool, the heat radiated from the surface of the blow-out pipe heats the condensate in the pool. The fluidity of the condensate is kept good by this, and the condensate does not stay in the pool,
Inhaled into the engine through small holes.

[0010]

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

As shown in FIGS. 1 and 2, 10 is a four-cylinder engine (main body), 11 is a surge tank provided in the middle of the intake system, and 12 to 15 are connected from the surge tank 11 to each cylinder of the engine. It is an intake pipe line.

The surge tank 11 includes intake pipe lines 12 to 15.
Is formed in a predetermined volume shape that is long in the column direction, and is formed from the upper and lower housings 16 and 17.

The upper housing 16 has a throttle chamber mounting portion 18 (not shown) formed at its longitudinal inlet end. In addition, at a predetermined position of the upper housing 16,
For example, the second intake pipe line 13 from the throttle chamber side
A blow-by gas outlet 20 connected to the blow-by gas passage 19 of the engine is formed above.

As shown in FIG. 3, in the lower housing 17, intake pipe lines 12 to 15 are opened at predetermined intervals in the column direction in the bottom portion 21 and are integrally formed in the lower housing 17.

The intake pipe lines 12 to 15 are extended from the opening of the lower housing 17 to the engine 10 side in a predetermined curved flow path, and a mounting flange 22 with a cylinder head (not shown) is integrally formed at the downstream end. .

A space is formed in the bottom portion 21 of the lower housing 17 along the intake pipe lines 12 to 15 immediately downstream of the openings of the intake pipe lines 12 to 15 as shown in FIGS. 4 and 5. As a result, a condensate pool 23 located above the intake conduits 12 to 15 is formed on the inner bottom of the surge tank 11.

The reservoir 23 is communicated with the intake conduit via the small hole 24. This small hole 24 is formed in the first, second and third intake pipe lines 12 to 1 close to the throttle chamber.
4 etc. In the figure, the small hole 24 is shown as the intake pipe lines 12-1.
Although it is provided at the top of No. 4, it is preferable to be provided at a deep portion of the reservoir 23 that is off the top.

On the other hand, a portion E of the exhaust gas is recirculated from the exhaust system to the throttle chamber side of the upper housing 16.
A connecting portion 26 of the GR passage (exhaust gas recirculation passage) 25 is formed, and an EGR gas blowing pipe 28 is attached to the connecting hole 27.

The blow-out pipe 28 is extended from the throttle chamber side to the vicinity of the reservoir above the second intake pipe line 13 and is formed so as to blow out the EGR gas.

The blow-by gas ventilation system will be described with reference to FIG. The blow-by gas that has leaked from the engine combustion chamber 30 to the crank chamber 31 is drawn into the intake system from the rocker chamber 33 through the blow-by gas passage 34 by the suction negative pressure generated on the downstream side of the throttle valve 32, and the combustion chamber 30 In the crank chamber 31, fresh air is introduced into the crank chamber 31 from the intake passage upstream of the throttle valve 32 through the fresh air introduction passage 35 and the rocker chamber 36.
Is ventilated.

With this structure, the blow-by gas sucked into the surge tank 11 from the blow-by gas outlet 20 is sucked into each cylinder through the intake pipe lines 12 to 15, while the oil content in the blow-by gas is Moisture or the like is partially condensed in the surge tank 11 and drips from each wall of the surge tank 11 to the pool 23 at the inner bottom, but the condensed liquid does not collect much in the pool 23.

That is, the EG is provided above the pool 23 of the condensate.
Since the R gas outlet pipe 28 is arranged and the high temperature EGR gas from the EGR passage 25 flows through the outlet pipe 28, the heat radiated from the surface of the outlet pipe 28 heats the condensate in the reservoir 23. Of.

Therefore, the moisture in the condensate is promoted to vaporize and is sucked into each cylinder together with the intake air. Further, the oil content is heated, so that the viscosity is lowered and the fluidity is improved, so that the oil content easily flows out through the small holes 24 and is sucked into each cylinder. The oil content is burned in the combustion chamber and discharged together with the exhaust gas.

Therefore, unlike the conventional example, there is no concern that the condensate will be excessively accumulated in the surge tank, and a large amount of the condensed condensate will not flow into the engine at one time to deteriorate the operability. The condensate resulting from gas or the like can be treated satisfactorily and accurately.

The EGR gas blowing pipe 28 is
It may be formed up to the intake pipe lines 14 and 15, but in this case, 1, 2 near the throttle chamber side, that is, the intake inflow side.
Condensation is likely to occur above the second intake pipe lines 12 and 13, and a large amount of the condensed liquid drops in the pool 23 in that part.
If the blow-out pipe 28 is arranged near the reservoir 23 above the second intake pipe lines 12 and 13, the condensate can be heated accurately.

[0026]

As described above, according to the present invention, in the internal combustion engine in which the surge tank provided in the intake system is connected to each cylinder through the intake pipe, the surge tank is provided with the blow-by gas passage from the engine and the exhaust system. EGR passages are connected to each other, and a reservoir for condensate such as oil is formed above the intake pipe at the inner bottom of the surge tank, and the reservoir for the condensate is introduced through a small hole. The EGR gas blow-out pipe from the EGR passage is arranged above the condensate pool and is connected to the EGR
Due to the heat of the gas, the fluidity of the condensate caused by the blow-by gas and the like can be maintained satisfactorily and can be processed accurately.

[Brief description of drawings]

FIG. 1 is an external view of a surge tank and an intake pipe line of an embodiment.

FIG. 2 is a side view.

FIG. 3 is a structural diagram of a lower housing and an intake pipe line.

FIG. 4 is a cross-sectional view taken along the line AA of FIG.

5 is a sectional view taken along line BB of FIG.

FIG. 6 is an explanatory diagram of a blow-by ventilation system.

[Explanation of symbols]

 11 Surge Tank 12-15 Intake Pipe Line 16 Upper Housing 17 Lower Housing 19 Blow-by Gas Passage 20 Blow-by Gas Blow Out 21 Bottom 23 Reservoir 24 Small Hole 25 EGR Passage 28 Ejection Pipe

Claims (1)

[Claims] 1. In an internal combustion engine in which a surge tank provided in an intake system is connected to each cylinder via an intake pipe, a blow-by gas passage from the engine and an EGR passage from an exhaust system are connected to the surge tank, respectively. , A reservoir for condensate such as oil is formed at a position above the intake pipe on the inner bottom of the surge tank, and the reservoir for the condensate is communicated with the intake pipe through a small hole. An intake system for an internal combustion engine, characterized in that a pipe for blowing EGR gas from the EGR passage is arranged above the reservoir of the.