JP5909770B2 - Intake passage structure - Google Patents

Description

  The present invention relates to the structure of an intake passage of an internal combustion engine (hereinafter referred to as “engine”), and in particular, relates to the structure of the intake passage from a point where blow-by gas is returned to the intake side to the throttle body.

  In a combustion chamber provided in the engine, fuel is mixed with intake air to perform explosive combustion. However, a part of the mixed gas mixed with fuel leaks to the crank chamber side. This leaked gas is called blow-by gas, and contains hydrocarbons, etc., and if discharged as it is, it leads to environmental pollution. Therefore, this blow-by gas is returned to the intake air and used as a recombustion gas.

  The point where blow-by gas is supplied to the intake side is often returned between the air cleaner and the throttle body. At this time, a problem arises in the treatment of the condensed droplets in the blow-by gas. These droplets contain not only fuel components but also particle components such as carbon components. Therefore, when this droplet adheres, there is a high possibility of solidifying.

  Therefore, if droplets adhere to the throttle shaft core of the throttle body, the throttle operation may be significantly hindered and cause malfunction.

  Patent Document 1 discloses a technique for forming a flange-like protruding wall portion that narrows the opening diameter of the intake passage immediately before the throttle. It is supposed that the progress of the liquid droplets flowing toward the throttle side is prevented by this protruding wall portion.

  Further, in Patent Document 2, in a downflow type intake passage, a technique is provided in which an annular step portion is provided for inducing droplets on the throttle valve side that opens downward when the throttle is opened, instead of the throttle shaft. Is disclosed.

Japanese Utility Model Laid-Open No. 02-119970 JP 2003-120245 A

  When the protruding wall portion is provided in the intake passage as in Patent Document 1, the opening diameter of the intake passage becomes narrow. In addition, the protruding wall portion in the intake passage hinders the flow of intake air, and the intake flow may generate turbulence near the protruding wall portion. When turbulent airflow is generated in the intake air, the flow of the intake air into the combustion chamber is affected, causing problems such as worsening of engine blow-up.

  In addition, providing an annular step on the inner surface of the intake passage as in Patent Document 2 complicates the mold when the intake passage is integrally formed. Further, even in the case of dividing and molding, it is necessary to pay attention to the accuracy of the joining portion of the steps at the time of joining later, and there is a problem that the manufacturing becomes complicated.

The present invention has been conceived in view of the above problems. More specifically,
An intake passage structure provided between the air cleaner and the throttle valve, to which a blow-by gas passage from the engine body is connected,
Wherein toward the throttle body inlet to the air cleaner side, convex groove shape toward the gravitational downward are formed to both of the intake passage roof and air intake passage floor,
The convex groove shape, the direction from the air cleaner side in the throttle body inlet, Ri a narrow groove width such that the width narrower than the throttle body inlet,
The width of the convex groove shape on the roof side is narrower than the width of the convex groove shape on the floor side,
The rotary shaft of the throttle valve is an intake passage structure according to claim Rukoto disposed substantially perpendicular to the formation direction of the floor-side convex groove shape.

  In the intake structure of the present invention, the condensed water (droplets) generated in the blow-by gas passage travels along the groove shape and flows in the vicinity of the center of the throttle rotation shaft. Occurrence can be prevented.

  Further, since the groove shape is provided along the intake passage, there is an effect that the flow of the intake air is not hindered.

It is a figure which shows the schematic structure of the engine carrying the intake passage structure of this invention. It is a figure which shows the upper surface view of the air cleaner cap which concerns on this invention. It is a figure which shows sectional drawing of AA and BB of FIG.

  The present invention will be described below with reference to the drawings. The following description exemplifies an embodiment of the present invention, and the following embodiment may be modified without departing from the gist of the present invention.

  FIG. 1 shows a schematic view of an engine having an intake passage structure 1 of the present invention. FIG. 1 shows a cylinder block 2, a cylinder head 3, a head cover 4, and an air cleaner 9 and an air cleaner cap 10 disposed above the head cover 4. An air cleaner pipe 8 is connected to the air cleaner 9. The direction of arrow 11i is the intake side of the engine, and the direction of arrow 11e is the exhaust side of the engine. The intake air is introduced from the air cleaner pipe 8, passes over the exhaust manifold 13, and is introduced into the air cleaner 9. Intake from the air cleaner 9 is introduced into the air cleaner cap 10.

  The air cleaner cap 10 is disposed on the head cover 4. The air cleaner cap 10 has a substantially L shape that bends to the intake side 11 i in the vicinity of the approximate center of the upper portion of the head cover 4. An opening 10 h is formed at the downstream end 10 e of the air cleaner cap 10 downward. The opening 10h communicates with an inlet 15i (see FIG. 2) of the throttle body 15 (see FIG. 3 (a)). Below the throttle body 15, a surge tank and an intake pipe to each cylinder are arranged.

  FIG. 2 shows a top view of the air cleaner cap 10. The solid line represents the bottom surface of the air cleaner cap 10. This bottom surface is the intake passage floor 10f (see FIG. 3A). Further, the one-point difference line represents the inner surface side of the top surface of the air cleaner cap 10. The top surface of the air cleaner cap 10 is an intake passage roof 10r (see FIG. 3A).

  Further, the upper side of the drawing is the direction of the connection port with the air cleaner 9. Accordingly, the intake air flows from the upper side to the lower side of the drawing, turns leftward (intake side 11i), and flows to the inlet 15i of the throttle body 15. A throttle valve 15 b is disposed on the throttle body 15.

  The throttle valve 15b is pivotally supported by a rotary shaft 15x, and rotates about the rotary shaft 15x by operating the throttle. By this rotation, the opening degree of the inlet 15i of the throttle body 15 changes. The rotation shaft 15x is disposed substantially at right angles to the streamline 16 from the upstream side to the downstream side of the intake air. In the throttle valve 15b, 15d corresponding to the upstream side of the intake flow rotates toward the lower side (the side opposite to the paper surface).

  Here, the streamline 16 is an imaginary line indicating a direction from the upstream side to the downstream side of the intake air in the vicinity of the opening 10 h of the downstream end 10 e of the air cleaner cap 10. A blow-by gas discharge port 18 is formed on the upstream side of the opening 10 h of the air cleaner cap 10.

  On the intake passage floor 10f, a floor groove shape 22 is formed in the vicinity of the opening 10h. The floor groove shape 22 increases in width from the width smaller than the diameter 20 of the opening 10h toward the upstream. The floor groove shape 22 is preferably formed to have a length of at least ¼ from the opening 10 h to the blow-by gas discharge port 18. The floor groove shape 22 is a groove that protrudes downward in the direction of gravity.

  Further, a roof convex shape 24 narrower than the groove width 22w of the floor groove shape 22 of the intake passage floor 10f is formed in the intake passage roof 10r. The roof convex shape 24 is a convex shape protruding downward in the direction of gravity. Further, the roof convex shape 24 may be formed up to the terminal end 10 t of the air cleaner cap 10.

  The intake passage floor 10f at the end 10t portion of the air cleaner cap 10 is formed with an end portion floor groove shape 23 that becomes narrower from the end 10t toward the opening 10h.

  Fig.3 (a) shows sectional drawing of AA of FIG. The intake air flows from the right side of the drawing toward the opening 10h. The air cleaner cap 10 is formed by attaching upper and lower members together. The upper member 10u constitutes an intake passage roof 10r, and the lower member 10d constitutes an intake passage floor 10f. The intake passage floor 10f and the intake passage roof 10r are substantially horizontal.

  FIG. 3B is a cross-sectional view taken along line BB in FIG. As described above, the floor groove shape 22 formed in the intake passage floor 10f is a groove recessed in the gravity downward direction. Also, the roof convex shape 24 formed on the intake passage roof 10r is a groove recessed downward in the gravitational force, and is a protrusion formed on the intake passage roof 10r when viewed from the inner surface of the intake passage.

  With reference to FIG. 2 again, the operation of the intake passage structure 1 of the present invention will be described. The intake air from the air cleaner pipe 8 is introduced into the air cleaner cap 10 via the air cleaner 9. In the air cleaner cap 10, the intake air flows toward the opening 10h (see FIG. 3A). At that time, the blow-by gas discharged from the blow-by gas discharge port 18 is mixed with the intake air and flows to the opening 10h. The opening 10 h communicates with the inlet 15 i of the throttle body 15.

  Moisture present in the relatively high-temperature blowby gas loses heat rapidly in the air cleaner cap 10 and therefore aggregates into droplets. This liquid also contains fine particle components such as carbon. The droplets aggregate on the inner wall in the air cleaner cap 10 and become droplets. Since there is an air flow toward the opening 10h in the intake passage, these droplets move toward the opening 10h.

  At this time, the droplets aggregated on the side surface in the intake passage flow toward the intake passage floor 10f (see FIG. 3A) due to gravity. Further, the liquid droplets aggregated on the top surface in the intake passage flow toward the intake passage floor 10f or flow toward the roof convex shape 24 of the intake passage roof 10r (see FIG. 3A). This is because the roof convex shape 24 is lower on the top surface side.

  The droplets flowing through the intake passage floor 10f flow into the groove shape of the floor groove shape 22 in the vicinity of the opening 10h. The groove width 22w of the floor groove shape 22 is narrower at the opening 10h than at the diameter 20 of the opening 10h. Accordingly, the droplets pass through the throttle body 15 without adhering to the rotating shaft 15x of the throttle valve 15b. Therefore, malfunction of the throttle valve 15b due to blow-by gas does not occur.

  Further, since the liquid droplets flowing through the roof convex shape 24 of the intake passage roof 10r are narrower than the groove width 22w of the floor groove shape 22, they drop into the floor groove shape 22 or flow to the terminal end 10t of the air cleaner cap 10.

  Referring to FIG. 3 (a), the droplet that has flowed to the end 10t of the air cleaner cap 10 is the end portion floor groove shape 23 (see FIG. 2) formed on the back side from the opening 10h of the intake passage floor 10f. It is captured and sent to the opening 10h. At this time, the groove width 22w (see FIG. 2) of the end portion floor groove shape 23 is also formed to be narrower than the diameter 20 of the opening 10h, so that the droplets do not adhere to the rotary shaft 15x of the throttle. Therefore, malfunction of the throttle valve 15b does not occur.

  As described above, in the intake passage structure of the present invention, the droplet mixed with the blow-by gas is guided with a width narrower than the diameter 20 of the throttle body inlet 15i, so the droplet does not adhere to the rotating shaft 15x. Therefore, the problem of malfunction of the throttle can be avoided. It is sufficient that at least one of the floor groove shape 22 or the roof convex shape 24 is formed, and preferably the floor groove shape 22 is formed.

  The present invention can be suitably used for the structure of an intake system of an engine.

DESCRIPTION OF SYMBOLS 1 Intake passage structure 2 Cylinder block 3 Cylinder head 4 Head cover 8 Air cleaner pipe 9 Air cleaner 10 Air cleaner cap 10e Downstream end (of the air cleaner cap) 10f Intake passage floor 10h (At the downstream end of the air cleaner cap) 10r Intake passage roof 11i Intake side 11e Exhaust side 13 Exhaust manifold 15 Throttle body 15i (Throttle body) inlet 15x Rotating shaft 16 Stream line 18 Blow-by gas outlet 19 Stream line 20 (opening) diameter 22 Floor groove shape 22w (floor groove shape) groove width 23 End Floor groove shape 24 Roof convex shape

Claims (1)

An intake passage structure provided between the air cleaner and the throttle valve, to which a blow-by gas passage from the engine body is connected,
Wherein toward the throttle body inlet to the air cleaner side, convex groove shape toward the gravitational downward are formed to both of the intake passage roof and air intake passage floor,
The convex groove shape, the direction from the air cleaner side in the throttle body inlet, Ri a narrow groove width such that the width narrower than the throttle body inlet,
The width of the convex groove shape on the roof side is narrower than the width of the convex groove shape on the floor side,
The rotary shaft of the throttle valve, an intake passage structure according to claim Rukoto disposed substantially perpendicular to the formation direction of the convex groove shape of the floor side.