JP3343303B2 - Engine blow-by gas recirculation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-by gas recirculation device for an engine, and more particularly to an improvement in the structure of a blow-by gas recirculation device which effectively prevents oil from adhering to a throttle valve.

[0002]

2. Description of the Related Art There is a blow-by gas recirculation device for recirculating blow-by gas in an engine crankcase to an intake pipe to prevent emission to the atmosphere. 6 and 7 show an example of a device for ventilating the air. The figure shows the opening position of the blow-by gas recirculation pipe 5, FIG. 6 is a vertical sectional view of the intake passage, and FIG. 7 is a horizontal sectional view. In the figure, a throttle body 1 having a throttle valve 3 provided therein is connected to a surge tank 2 having an upstream end tapered, and a blow-by gas recirculation pipe 5 extending horizontally is connected to a surge tank 2 immediately after the throttle valve 3. The tapered wall has an opening.

[0003]

By the way, in the above-mentioned conventional structure, when the opening of the throttle valve 3 is small and the load is light, as shown by the arrow in FIG.
It flows out from a small gap at the top and bottom as a high-speed flow,
Behind the throttle valve 3 where the pressure has decreased, a strong vortex flows around here. The vortex causes the return pipe 5
The blow-by gas that flows more flows behind the throttle valve 3, and the oil contained in the gas adheres to the throttle valve 3 to form a deposit, which may hinder valve operation. A backflow toward the throttle valve 3 also occurs in a horizontal plane (FIG. 7), and the backflow causes blow-by gas to flow behind the throttle valve 3 and similarly causes oil to adhere.

In Japanese Utility Model Laid-Open Publication No. 56-161166, a venturi is provided in an intake pipe downstream of a throttle valve, a blow-by gas recirculation pipe is opened in the cylinder wall, and the throttle valve is sufficiently throttled. One that guarantees blow-by gas recirculation has been proposed. However, even in the present structure, the influence of the vortex behind the throttle valve is unavoidable, and there is a possibility that a deposit may occur.

An object of the present invention is to provide a blow-by gas recirculation device for an engine which does not cause an oil film to adhere to a throttle valve.

[0006]

In a first configuration of the present invention, in order to solve the problems], as well as expanded the engine intake pipe at a location downstream of the throttle valve 3, suction tubes 1 so the same diameter as the inner tube 41
As described above, a predetermined length is extended into the large-diameter downstream intake pipe 2 from the large-diameter portion 21 to form an annular gas between the internal pipe 41 and the inner wall of the downstream intake pipe 2 located outside the internal pipe 41. Channel 2
2 is formed, allowed to open the blow-by gas recirculation pipe 5 to the gas passage 22, and the length of the inner tube 41, the moth
The opening 221 at the downstream end of the flow path 22 is
The length at the position downstream of the opening 51 of the reflux tube 5
It was done.

In the second structure of the present invention, the blow-by gas recirculation pipe 5 is opened at the lowermost end wall of the large-diameter portion 21, and the opening 51 near the tip end of the inner pipe 41. The inner wall 2a of the downstream side intake pipe 2 is tilted down to the above.

In the third configuration of the present invention, the gas flow path 2
2, the exhaust gas recirculation pipe 6 is further opened.

In a fourth configuration of the present invention, the upstream intake pipe 1 is a throttle body, and the downstream intake pipe 2 is a surge tank.

[0010]

In the above first configuration, the gas flow path 22 for the blow-by gas is provided with the throttle valve 3 that generates a vortex or a backflow.
The downstream region is isolated by the wall of the inner tube 4 and is not affected by the inner wall. In addition, the rapid flow flowing out of the opening gap of the throttle valve 3 flows along the inner circumference of the inner pipe 4, and
A so-called ejector effect occurs, and the blow-by gas in the gas flow path 22 is drawn out from the opening 221 of the flow path 22 by a rapid flow toward the downstream. Thus, the blow-by gas is conveyed toward the downstream engine without going to the throttle valve 3.

In the second configuration, when the engine is stopped, oil and moisture due to dew may be generated in the gas passage 22, but since the inner wall of the downstream intake pipe 2 is inclined downward at the lowest position, the oil And the like are efficiently discharged from the gas passage 22 to prevent icing from occurring.

In the third configuration, by opening the exhaust gas recirculation pipe 6 to the gas flow path 22, it is possible to prevent the exhaust gas recirculated by EGR from flowing back to the throttle valve 3 and generating a deposit.

In the fourth configuration, the present invention can be easily realized by using the throttle body and the surge tank 2 having a larger diameter.

[0014]

In FIG. 1, a surge tank 2 as a downstream intake pipe is a large-diameter tubular body, and a plurality of intake branch pipes 23 to an engine cylinder are provided on a side wall. Surge tank 2
The throttle body 1 which is a small-diameter upstream intake pipe is connected via a gasket 4 to one end wall of the throttle body 1. The throttle body 1 is provided with a throttle valve 3 at a connection end.

FIGS. 2 and 3 show details of the connecting portion 21 between the throttle body 1 and the surge tank 2, wherein FIG. 2 is a vertical sectional view and FIG. 3 is a horizontal sectional view. The gasket 4 includes a cylindrical portion 41 having the same diameter as the throttle body 1 and a flange portion 42 formed at one end of the cylinder portion 41.
And the end wall of the surge tank 2. As a result, the intake path becomes the throttle body 1
The diameter of the connecting portion 21 of the surge tank 2 is increased stepwise, and the cylindrical portion 41 of the gasket 4 is formed as an inner cylinder in the surge tank 2 and extends at a constant length.

An annular gas flow path 22 is formed over the entire circumference between the outer circumference of the inner cylinder 41, which is the inner pipe, and the surge tank inner wall 2a. The blow-by gas recirculation pipe 5 extending from a PCV (Positive Crankcase Ventilation) valve (not shown) is open toward 22 (reference numeral 51 in FIG. 2). Inside
The length of the cylinder 41 is such that the downstream opening 221 of the gas flow path 22 is upward.
Downstream of the opening 51 of the blow-by gas recirculation pipe 5
It is the length of the position. In this portion, the inner wall 2 a of the surge tank 2 is inclined downward toward the opening 221 of the gas flow path 22.

An exhaust gas recirculation pipe 6 for EGR is connected to the gas passage 22 from the horizontal direction through the side wall of the surge tank 2 (FIG. 3).

The operation of the blow-by gas recirculation device having the above structure will be described below. As shown in FIG. 4, the opening degree of the throttle valve 3 at a light load is small, and the intake air flows out of the small gap above and below the throttle valve 3 as a high-speed flow to the downstream side as shown by arrows in the figure. The pressure behind the throttle valve 3 is reduced, and a part of the outflowed intake air is swirled toward the upstream throttle valve. Here, in the present embodiment, the gas flow path 22 is isolated from the downstream region of the throttle valve in which the vortex is generated by the cylinder wall of the inner cylinder 41.
The blow-by gas flowing through 2 is not affected by the vortex at all. In addition, since there is a high-speed intake flow toward the downstream near the opening 221 of the gas flow path 22, the blow-by gas in the gas flow path 22 is drawn by the intake flow by the ejector effect and quickly enters the surge tank 2. The effluent is refluxed. Thus, the blow-by gas does not flow backward in the direction of the throttle valve, and the occurrence of deposit is prevented.

A similar effect is obtained for the recirculated exhaust gas, as shown in FIG.
The exhaust gas that has flowed into 2 is not affected by the backflow in the direction of the throttle valve due to the wall of the inner cylinder 41, and is quickly discharged into the surge tank 2 by the ejector effect of the intake airflow that flows downstream.

In the lowermost position of the end wall of the surge tank 2, the gas flow path 2
Since the inner wall 2a of the surge tank (see FIG. 2) is inclined downward toward the opening 221 of the second, oil and moisture in the gas flow path are satisfactorily discharged into the surge tank 2 without icing or the like. .

In the above embodiment, if the installation space allows, if the exhaust gas recirculation pipe 6 is provided at the lowest position of the surge tank 2 and adjacent to the booby-by gas recirculation pipe 5,
Exhaust gas can be more efficiently recirculated.

[0022]

As described above, according to the blow-by gas recirculation system for an engine of the present invention, the reverse flow of the blow-by gas recirculated into the intake pipe can be effectively prevented, and deposits of oil and the like occur on the throttle valve. Thus, it is possible to solve the problem of malfunction.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view of a surge tank portion showing one embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of an end portion of a surge tank showing a connection portion with an intake pipe.

FIG. 3 is an enlarged horizontal sectional view of a surge tank end showing a connection portion with an intake pipe.

FIG. 4 is a schematic vertical sectional view of a surge tank end showing operation of the apparatus.

FIG. 5 is a schematic horizontal sectional view of a surge tank end showing an operation of the apparatus.

FIG. 6 is a schematic vertical sectional view of a conventional surge tank end showing a connection portion with an intake pipe.

FIG. 7 is a schematic horizontal sectional view of a conventional surge tank end showing a connection portion with an intake pipe.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Throttle body (upstream intake pipe) 2 Surge tank (downstream intake pipe) 2a Inner wall 21 Connection part (expansion part) 22 Gas flow path 221 opening 3 Throttle valve 4 Gasket 41 Inner cylinder ( inner pipe ) 5 Blow-by gas recirculation Pipe 51 Opening 6 Exhaust gas recirculation pipe

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Takikawa 14 Iwatani, Shimowasumi-cho, Nishio-shi, Aichi Prefecture Inside the Japan Automobile Parts Research Institute Co., Ltd. (72) Inventor Hiroshi Kawai 1st Toyota-cho Toyota-shi, Aichi Prefecture In-company (72) Inventor Akira Ii 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A-2-233817 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01M 13/00 F02M 25/07 580 F02M 35/10

Claims (4)

(57) [Claims] The method according to claim 1 engine intake pipe with a diameter increasing in the downstream position of the throttle valve, and allowed to extend from the enlarged diameter portion of the suction tubes as the inner tube of the same diameter and which the downstream side intake pipe of large diameter, An annular gas flow path is formed between the inner pipe and the inner wall of the downstream intake pipe located outside the inner pipe, and a blow-by gas recirculation pipe is opened in the gas flow path .
The opening at the downstream end of the gas flow path is
Length at the downstream side of the opening position of the bigas reflux pipe
Blow-by gas feedback device for an engine, characterized in that the the. 2. The blow-by gas recirculation pipe is opened at an end wall at the lowermost position of the enlarged diameter portion, and the inner wall of the downstream intake pipe is inclined downward from the opening to a position near a tip end of the inner pipe. The blow-by gas recirculation system for an engine according to claim 1, wherein 3. The blow-by gas recirculation device for an engine according to claim 1, wherein an exhaust gas recirculation pipe is further opened in the gas flow path. 4. The system according to claim 1, wherein the upstream intake pipe is a throttle body, and the downstream intake pipe is a surge tank.
4. The blow-by gas recirculation device for an engine according to any one of claims 3 to 3.