JP5489869B2 - Intake device for internal combustion engine - Google Patents

Description

  The present invention relates to an intake device having two intake ports for one cylinder among intake devices in an internal combustion engine.

  As shown in FIG. 1 and FIG. 2, in the prior arts 1 and 2 and the like, two intake ports C are provided side by side in the combustion chamber B at the top of one cylinder A, so that each intake port is provided. An intake device is described which is configured to give two tumble flows T swirling in the direction of the axis A1 in the cylinder A to the intake air introduced into the cylinder A from C.

  In FIGS. 1 and 2, symbol D indicates a piston, symbol E indicates two exhaust ports, and symbol F indicates a spark plug.

  Further, in Patent Documents 1 and 2 out of Patent Documents 1 and 2, assuming the intake device, the shape of the passage cross section when each intake port C is viewed from the direction of the center line C1 in the longitudinal direction, As shown in FIGS. 3 (a) and 3 (b), each intake port is formed asymmetrically on the left and right with an orthogonal axis C2 parallel to the axis A1 of the cylinder A and perpendicular to the center line C1. The velocity of the flow (indicated by the solid line arrow T ′) in the portion C ′ inside the center line C1 (or the orthogonal axis C2) in C and the center line C1 (or in each intake port C) (or Strengthening the tumble flow T in each intake port C by giving a speed difference between the speed of the flow (indicated by the dotted arrow T ") in the portion C" outside the orthogonal axis C2). Has proposed.

  In particular, in Patent Document 2, in order to form the cross-sectional shape of each intake port C in an asymmetric shape on the right and left with respect to the orthogonal axis C2, as shown in FIG. The passage cross-sectional area of the portion C ′ inside the center line C1 (or the orthogonal axis C2) of the inside is inclined by the inclined surface G provided on the ceiling inside each intake port C). Is made narrower than the passage cross-sectional area in the portion C ″ outside the center line C1 (or the orthogonal axis C2), the flow velocity in the inner portion C ′ is made to flow in the outer portion C ″. A case (former case) is described in which the speed is higher than the speed.

  Further, in Patent Document 2, as shown in FIG. 3B, the passage cross-sectional area in the portion C ″ outside the center line C1 (or the orthogonal axis C2) in each intake port C is calculated. , The inclined surface H provided on the ceiling in each intake port C is narrower than the cross-sectional area of the passage C in the portion C ′ inside the center line C1 (or the orthogonal axis C2) of each intake port C. Thus, there is described a case where the flow velocity in the outer portion C ″ is made higher than the flow velocity in the inner portion C ′ (the latter).

JP 09-105330 A JP 2004-144071 A

  However, since the outer portion C ″ in each intake port C is close to the arcuate inner peripheral wall surface of the cylinder A when viewed from the direction of the axis A1 in the cylinder A, FIG. (B) When the flow velocity in the outer portion C ″ is increased on the inclined surface H as in (the latter), the soot intake with the flow velocity increased on the inclined surface H is It spreads (escapes) to the inner portion C ′ of each intake port C along the inclined surface H, and in addition to the flow velocity decreasing, it collides with the arc-shaped inner peripheral wall surface of the cylinder A. Therefore, there is a problem that the tumble flow T is weakened by this amount.

  On the other hand, as shown in FIG. 3A (the former) in Patent Document 2, the flow velocity in the inner portion C ′ in each intake port C is increased on the inclined surface G. In this case, since this fast flow velocity can be positioned at the center of the cylinder A when viewed from the direction of the axis A1 in the cylinder A, a stronger tumble flow T can be obtained than in the latter case.

  However, on the other hand, in the inner portion C ′ of each intake port C, the soot intake whose flow velocity is increased by the inclined surface G is the outer portion of each intake port C along the inclined surface G. Since it spreads to C ″ (escapes) and the flow velocity decreases, the effect of strengthening the tumble flow is low.

  Therefore, in the case of the configuration shown in FIGS. 3 (a) and 3 (b), the above-mentioned Patent Document 2 is based on the center line C1 (or the orthogonal axis C2) as shown by a two-dot chain line in each intake port C. In addition, by providing a partition plate K that divides the inner portion C ′ and the outer portion C ″, the flow of intake air from the inner portion C ′ to the outer portion C ″, or the flow of intake air in the opposite direction Has been proposed to prevent

  However, according to this configuration, the flow resistance of the intake air is greatly increased by the partition plate K, and similarly, the effect of strengthening the tumble flow is low.

  It is a technical object of the present invention to provide an intake device that solves these problems.

In order to achieve this technical problem, claim 1
“By arranging two intake ports facing down toward the cylinder at the top of the cylinder, a tumble flow that swirls in the direction of the axis of the cylinder is applied to the intake air introduced from each intake port into the cylinder. In the intake device configured as described above,
The ceiling surface in the portion inside each intake port, as viewed from the axial direction of the cylinder, is lower than the ceiling surface in the portion outside each center line in each intake port. Thus, the passage cross-sectional area in the inner portion is configured to be smaller than the passage cross-sectional area in the outer portion, and the ceiling surface in the inner portion is viewed from the direction of the center line in the intake port, It was set as the structure which inclines diagonally downward toward the said outer part. "
It is characterized by that.

  In this configuration, out of the intake air flowing toward the cylinder in each intake port, the flow velocity in the portion inside the center line of the intake port is the amount in the outer portion corresponding to the lower ceiling surface in the inner portion. It is faster than the flow rate.

  In this case, the ceiling surface in the inner portion faces the outer portion in the direction opposite to the inclined surface G in FIG. 3A of Patent Document 2 when viewed from the direction of the center line of the intake port. Therefore, it is possible to reliably reduce the intake air flowing through the inner part from spreading (escape) to the outer part by the inclination of the ceiling surface.

  As a result, the intake air in the portion inside the orthogonal axis in each intake port is not provided with the partition plate K in the intake port as in Patent Document 2, and thus without increasing the flow resistance. Because a fast flow velocity can be secured and a strong tumble flow can be applied to the center of the cylinder, the effect of the tumble flow from the two intake ports can be greatly improved.

It is a perspective view which shows the conventional intake device. It is a top view of FIG. FIG. 3 is an enlarged sectional view taken along line III-III in FIG. 2. FIG. 6 is a longitudinal sectional front view showing the embodiment of the present invention, and is a sectional view taken along the line IV-IV in FIG. 5. FIG. 5 is a VV plan sectional view of FIG. 4. FIG. 6 is an enlarged sectional view taken along line VI-VI in FIGS. 4 and 5. FIG. 7 is an enlarged sectional view taken along the line VII-VII in FIGS. 4 and 5.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  In these drawings, reference numeral 1 denotes a cylinder block having a cylinder 2, and a piston (not shown) is built in the cylinder 2.

  Reference numeral 3 denotes a cylinder head fastened to the cylinder block 1 so as to close the top of the cylinder 2, and a combustion chamber 4 that opens to the top of the cylinder 2 is formed in the lower surface of the cylinder head. Two intake ports 5 to the combustion chamber 4 are formed side by side when viewed from the direction of the axis 2 a in the cylinder 2.

  Each intake port 5 applies a tumble flow that turns in the direction of the axis 2a in the cylinder 2 to the intake air introduced into the cylinder 2 from each intake port 5 as in the conventional case shown in FIG. A poppet type intake valve 7 is provided at a portion of the valve seat 6 where each intake port 5 opens into the combustion chamber 4.

  In the case of the present embodiment, the two intake ports 5 are bifurcated from one inlet port 8 that opens to the side surface 3a of the cylinder head 3 when viewed from the direction of the axis 2a of the cylinder 2. It is configured to branch. Of course, in another embodiment, the two intake ports 5 can be opened separately on the side surface 3 a of the cylinder 3.

  When viewed from the direction of the axis 2a in the cylinder 2, the interior of each intake port 5 is, as shown in FIG. 5, a portion 5 'inside the longitudinal center line 5a in the intake port 5, The axis 2a of the cylinder 2 is formed by a portion 5 ″ outside the center line 5a or when viewed from the direction of the center line 5a in the intake port 5, as shown in FIG. It is formed by a portion 5 'inside the orthogonal axis 5b parallel to and perpendicular to the center line 5a, and a portion 5' 'outside the orthogonal axis 5b.

  By making the ceiling surface 5c 'of the inner portion 5' of each intake port 5 lower than the ceiling surface 5c "of the outer portion 5", the passage sectional area of the inner portion 5 'is reduced. , The passage cross-sectional area of the outer portion 5 ″ is made narrower, so that the speed of the intake air flowing through the inner portion 5 ′ as indicated by the solid line arrow T ′ is set to the outer portion 5 ″. Is made faster than the velocity of the intake air flowing as indicated by the dotted arrow T ″.

  When the ceiling surface 5c 'of the inner portion 5' is viewed from the direction of the center line 5a of the intake port 5, as shown in FIGS. 6 and 7, an appropriate angle θ is directed toward the outer portion 5 ″. It is configured to tilt only diagonally downward.

  Further, the inner bottom surface 5d of each intake port 5 is formed on the bottom surface of the ship such that the center line 5a or the orthogonal axis 5b of the inner bottom surface 5d is the lowest and is inclined obliquely upward from this portion. ing.

  In this configuration, of the intake air flowing in each intake port 5 toward the cylinder 2, the flow velocity indicated by the solid line arrow T ′ in the inner portion 5 ′ of the center line 5 a of the intake port 5 is the inner portion 5. The flow velocity indicated by the dotted arrow T ″ in the outer portion 5 ″ is increased by the amount by which the ceiling surface 5c ′ is lowered.

  In this case, the ceiling surface 5c ′ of the inner portion 5 ′ is inclined obliquely downward by an appropriate angle θ toward the outer portion 5 ″ when viewed from the direction of the center line 5a of the intake port 5. Thus, the intake air flowing through the inner portion 5 ′ can be reliably reduced (escaped) from spreading to the outer portion 5 ″ by the inclination of the ceiling surface 5c ′. A fast flow velocity can be reliably ensured for the intake air in the inner portion 5 ′.

  In the above-described embodiment, the ceiling surface 5c 'in the inner portion 5' in each intake port 5 is more than the valve seat 5c "in the outer portion as shown in FIG. The structure is inclined obliquely downward so as to gradually become lower toward the mouth 6.

  According to this configuration, the intake of the solid arrow T ′ whose flow velocity is increased at the ceiling surface 5c ′ in the inner portion 5 ′ can be directed to the central portion in the cylinder 2 while further increasing the flow velocity. There is an advantage that the effect of the tumble flow can be promoted more reliably.

  Furthermore, in the above-described embodiment, as shown in FIG. 4, both the ceiling surface 5c 'in the inner portion 5' and the ceiling surface 5c "in the outer portion are connected to the valve seat port by these extension lines. 6 is configured so as not to be disengaged from the valve seat port 6.

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder 2a Cylinder axis 3 Cylinder head 4 Combustion chamber 5 Intake port 5 'Inner part 5 "Outer part 5a Intake port center line 5b Orthogonal axis 5c' Inner part ceiling surface 5c" Outer part Of the ceiling 6 Valve seat 7 Intake valve

Claims (1)

By arranging two intake ports facing down toward the cylinder at the top of the cylinder, a tumble flow swirling in the direction of the axis of the cylinder is imparted to the intake air introduced from the intake ports into the cylinder. In the air intake device configured as follows:
The ceiling surface in the portion inside each intake port, as viewed from the axial direction of the cylinder, is lower than the ceiling surface in the portion outside each center line in each intake port. Thus, the passage cross-sectional area in the inner portion is configured to be smaller than the passage cross-sectional area in the outer portion, and the ceiling surface in the inner portion is viewed from the direction of the center line in the intake port, An intake device for an internal combustion engine, wherein the intake device is inclined obliquely downward toward the outer portion.

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