JP2007198303A - Intake port of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To concurrently secure both strong swirl and high charging efficiency. <P>SOLUTION: The upper wall surface 14 of an intake port 4 at the intake air inflow passage part 8 is formed of a first upper wall surface 14a and a second upper wall surface 14b lower than the first upper wall surface 14a. A lower layer flow passage X and an upper layer flow passage Y are formed on both sides of the top part of the second upper wall surface 14b. The side wall surface 9 of a spiral part 7 so extends as to close the downstream end of the lower layer flow passage X. A lower layer flow guide pipe 20 extending from the lower layer flow passage X to an intake valve opening area Z is installed. A lower layer flow flowing in the lower layer flow passage X produces swirl by flowing in the circumferential direction of a combustion chamber 3 after passing through the intake valve opening area Z when the intake valve 6 is opened. An upper layer flow flowing in the upper layer flow passage Y flows into the combustion chamber 3 after passing through the spiral part 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an intake port of an internal combustion engine of the present invention.

  A first portion is formed by a spiral portion formed around the axis of the intake valve and an intake air inflow passage portion extending tangentially from the spiral portion, and the intake air inflow passage portion is tangentially connected to the peripheral wall surface of the spiral portion. And a second side wall surface extending to the circumferential wall surface of the spiral portion toward the valve shaft of the intake valve, the upper wall surface of the intake air inflow passage portion is the first side wall surface described above. A first upper wall surface located on the side and smoothly connected to the upper wall surface of the spiral portion, and a second upper wall surface located on the second side wall surface side and having a height lower than that of the first upper wall surface A lower flow that flows along the bottom wall surface of the intake air inflow passage portion and an upper flow that flows along the first upper wall surface at the height position of the second upper wall surface. A helical intake port is known in which swirl is generated in the combustion chamber by the flow. (See Patent Document 1).

In this helical type intake port, when the intake air amount is large, the swirling action of the upper layer flow in the spiral portion is weakened by the lower layer flow, thereby preventing the occurrence of excessive swirl in the high engine speed region.
Japanese Utility Model Publication No. 2-147830

  By the way, in this helical type intake port, swirl is generated in the combustion chamber by swirling the intake air in the spiral portion as in the conventional helical type intake port. In this case, in order to strengthen the swirl, the swirling action in the spiral portion must be strengthened. However, if the swirling action in the spiral portion is increased, the suction resistance increases, so that the charging efficiency is lowered, and as a result, the output during the maximum load operation is lowered.

As long as the swirl is strengthened by strengthening the swirling action in the spiral part, it is difficult to ensure a strong swirl and high filling efficiency at the same time. To ensure a strong swirl and high filling efficiency at the same time Needs a change of mindset.
The inventor has studied the flow of intake air over a long period of time, and finally found an intake port that can simultaneously ensure a strong swirl and high filling efficiency.

  That is, according to the present invention, the peripheral wall surface is configured by the spiral portion formed around the axis of the intake valve and the intake air inflow passage portion extending tangentially from the spiral portion, and the spiral portion extends around the axis of the intake valve. A first side wall surface tangentially connected to the peripheral wall surface of the spiral portion, and an intake valve In the intake port of the internal combustion engine defined by the second side wall surface extending toward the peripheral wall surface of the spiral portion toward the valve shaft, the upper wall surface, and the bottom wall surface, the lower end outlet portion of the spiral portion is the top surface of the combustion chamber. An intake air inflow passage portion is arranged at the peripheral portion so that the first side wall surface extends tangentially to the peripheral portion of the combustion chamber. Among the annular intake valve openings formed between the seats, the cylinder axis An intake valve opening region formed on the opposite side of the intake air inflow passage portion with respect to a plane including the central portion of the air valve body exists, and the intake air inflow passage portion is located below the intake air inflow passage portion. An upper layer flow that flows above the flowing lower layer flow and the intake air inflow passage portion is generated, and in order to guide the lower layer flow to the intake valve opening region, the intake air inflow passage portion crosses the inside of the spiral portion and enters the intake valve opening region. A lower flow guide pipe extending toward the engine is provided, and when the intake valve is opened, the lower flow is led to the intake valve opening area by the lower flow guide pipe and flows into the combustion chamber from the intake valve opening area toward the periphery of the combustion chamber. As a result, a swirl is generated in the combustion chamber, and the upper layer flow is swirled in the spiral portion when the intake valve is opened, and then dispersed from the entire intake valve opening and flows into the combustion chamber.

  A swirl is generated by the lower flow flowing in the lower flow guide pipe, and high filling efficiency is ensured by the upper flow flowing in the upper flow path.

  1 to 3, reference numeral 1 denotes a cylinder block, 2 denotes a cylinder head, and 3 denotes a combustion chamber. In the embodiment shown in FIG. 1, a pair of intake ports 4 and 5 are formed in the cylinder head 2, and a pair of exhaust ports are formed in the cylinder head 2 although not shown in FIG. Yes. The present invention relates to one intake port 4 indicated by a solid line in FIG. 1 of the pair of intake ports 4 and 5, and therefore only the intake port 4 will be described below.

  Referring to FIGS. 1 to 3, the intake port 4 is constituted by a spiral portion 7 formed around the axis of the intake valve 6 and an intake air inflow passage portion 8 extending tangentially from the spiral portion 7. As shown in FIGS. 1, 2, and 3 (C), the spiral portion 7 includes a peripheral wall surface 9 that extends around the axis of the intake valve 6, an upper wall surface 10, and a lower end outlet portion 11 that is opened and closed by the intake valve 6. 1 and 2, the intake air inflow passage portion 8 includes a first side wall surface 12 tangentially connected to the peripheral wall surface 9 of the spiral portion 7, and a valve of the intake valve 6. It is demarcated by the 2nd side wall surface 13 extended to the surrounding wall surface 9 of the spiral part 7 toward the axis | shaft 6a, the upper wall surface 14, and the bottom wall surface 15. FIG.

  As can be seen from FIG. 1, the lower end outlet portion 11 of the spiral portion 7 is disposed at the peripheral portion of the top surface 16 (FIG. 2) of the combustion chamber 3, and the first side wall surface 12 is tangent to the peripheral portion of the combustion chamber 3. An intake air inflow passage portion 8 is arranged so as to extend in a shape. That is, as shown in FIG. 1, the downstream side of the intake air inflow passage portion 8 extends tangentially to the peripheral edge of the combustion chamber 3, and the upstream side of the intake air inflow passage portion 8 is for layout reasons. It is slightly bent in the direction away from the combustion chamber 3 with respect to the downstream side of the intake air inflow passage portion 8.

  FIG. 5 is a perspective view schematically showing the intake port 4. Referring to FIGS. 1 to 3 and FIG. 5, the upper wall surface 14 of the intake air inflow passage portion 8 is located on the first side wall surface 12 side at least downstream of the intake air inflow passage portion 8 and A first upper wall surface 14a that smoothly connects to the upper wall surface 10 and a second upper wall surface 14b that is located on the second side wall surface 13 side and located on the bottom wall surface 15 side with respect to the first upper wall surface 14a. Composed. The cross-sectional shape of the intake air inflow passage portion 8 where the second upper wall surface 14b is formed at a lower position than the first upper wall surface 14a is shown by hatching in FIG.

  As can be seen from FIGS. 3A to 3C and FIG. 5, the first upper wall surface 14a descends gradually toward the spiral portion 7 while the lateral width gradually decreases, and then the upper wall surface of the spiral portion 7 as described above. 10 is connected smoothly. The upper wall surface 10 of this spiral part 7 extends over almost ¾ of the entire circumference of the spiral part 7 while gradually descending along the peripheral part of the spiral part 7. On the other hand, the width of the second upper wall surface 14 b is approximately 1/3 of the width of the bottom wall surface 15 on the downstream side of the intake air inflow passage portion 8 and is constant, and on the upstream side of the intake air inflow passage portion 8. It gradually becomes ugly as you go to.

  On the other hand, as shown in FIGS. 3A to 3C and FIG. 5, the first upper wall surface 14 a and the second upper wall surface 14 b extend in a substantially horizontal direction within the cross section of the intake air inflow passage portion 8. The wall surface 17 located between the first upper wall surface 14a and the second upper wall surface 14b is a downward inclined surface. The width of the inclined surface 17 gradually increases toward the spiral portion 7. On the other hand, as shown in FIG. 2, the second upper wall surface 14b is also lowered toward the spiral portion 7. In this case, the inclination angle of the second upper wall surface 14b is larger than the inclination angle of the first upper wall surface 14a. large.

  When the first upper wall surface 14a and the second upper wall surface 14b are formed stepwise in this way, the lower portion of the first side wall surface 12 is shown in the intake air inflow passage portion 8 as indicated by hatching X in FIG. A lower channel defined by the second side wall surface 13, the second upper wall surface 14b, and the bottom wall surface 15, and a lower channel and the first upper wall surface above the lower channel as indicated by hatching Y. The upper flow path located between 14a is formed. That is, in the intake air inflow passage portion 8, two flows are generated: a lower layer flow flowing in the lower layer flow path X and an upper layer flow flowing in the upper layer flow path Y.

  FIG. 4 shows an enlarged view of FIG. When the intake valve 6 is opened as shown in FIGS. 2 and 3C, an annular intake valve opening 19 is formed between the intake valve 6 and the valve seat 18 of the intake valve 6. In this case, in the annular intake valve opening 19 formed between the intake valve 6 and the valve seat 18 of the intake valve 6 when the intake valve 6 is fully opened, the cylinder axis O and the center of the valve body of the intake valve 6 in FIG. There is an intake valve opening region formed on the opposite side of the intake air inflow passage portion 8 with respect to the plane K including the portion.

This intake valve opening region is indicated by Z in FIGS.
This intake valve opening region Z is in a range M of approximately 90 degrees in the swirling direction of the intake air flow in the spiral portion 7 from the intersection of the plane K and the intake valve opening 19 on the peripheral edge side of the combustion chamber 3 in FIG. is there.

  On the other hand, as shown in FIGS. 1, 2, and 4, the side wall surface 9 of the spiral portion 7 extends so as to close the downstream end of the lower layer flow path X. More specifically, the side wall surface portion 9a of the spiral portion 7 that closes the downstream end of the lower layer flow path X has a bottom wall surface 15 facing downward from the downstream end of the second upper wall surface 14b as shown in FIG. The side wall surface portion 9a extends over the entire width of the second upper wall surface 14b from the second side wall surface 13 toward the first side wall surface 12, as shown in FIG. It extends.

  In the intake port 4, a lower flow guide pipe 20 extending from the intake air inflow passage portion 8 across the spiral portion 7 toward the intake valve opening region Z is provided in order to guide the lower flow to the intake valve opening region Z. It has been. The lower flow guide tube 20 passes through the side wall surface portion 9a of the spiral portion 7 that closes the downstream end of the lower flow passage X, and crosses the spiral portion 7 from the lower flow passage X to the intake valve opening region Z. It extends toward. In the embodiment shown in FIGS. 1 to 5, the lower flow guide tube 20 is formed of a hollow cylinder.

  When such a lower flow guide pipe 20 is provided, the lower flow flowing in the lower flow path X below the second upper wall surface 14b advances through the lower flow guide pipe 20 when the intake valve 6 is opened, As shown by an arrow S, the air flows from the intake valve opening region Z into the combustion chamber 3 toward the periphery of the combustion chamber 3, thereby generating a strong swirl around the cylinder axis O in the combustion chamber 3. It is done.

  On the other hand, the upper layer flow flowing in the upper layer flow path Y advances in the upper layer flow path Y when the intake valve 6 is opened, and then swirls in the spiral portion 7 to open the intake valve opening as shown by an arrow T in FIG. Dispersed from the entire portion 19 and flows into the combustion chamber 3. Thus, the amount of intake air can be increased by allowing the intake air to flow from the entire intake valve opening 19. That is, if the upper layer flow is caused to flow into the combustion chamber 3 without swirling, most of the upper layer flow flows into the combustion chamber 3 only from the intake valve opening on the side opposite to the intake air inflow passage portion 8. Become. This is substantially the same as the flow passage area of the intake valve opening being reduced, and therefore an increase in the intake air amount cannot be expected.

  On the other hand, when a swirl flow is given to the upper layer flow in the spiral portion 7, the upper layer flow is dispersed from the entire intake valve opening 19 and flows into the combustion chamber 3 as described above. This is the same as the flow passage area of the intake valve opening 19 is increased, and therefore the intake air amount is increased, so that the charging efficiency is improved. In this way, in the present invention, the swirl flow is generated in the spiral portion 7 for the purpose of improving the filling efficiency and not for the generation of swirl as in the prior art.

  On the other hand, when the intake air is swirled in the spiral portion 7 and flows into the combustion chamber 3, it seems as if the swirled intake air flow is shifted to the swirl flow as it is. However, it is a part of the swirling intake air flow that is directed toward the periphery of the combustion chamber 3 that contributes to the generation of swirl. Therefore, even if the intake air is swirled and flows into the combustion chamber 3 Actually, only a part of the intake air contributes to the generation of the swirl. That is, in order to generate a swirl, it is most effective to generate a strong intake air flow toward the periphery of the combustion chamber 3 as in the present invention.

  If the side wall surface portion 9a of the spiral portion 7 is not provided, the lower layer flow toward the intake valve opening region Z passing under the second upper wall surface 14b and the upper layer flow that starts to swirl in the spiral portion 7 interfere with each other. As a result, a strong swirl cannot be obtained. On the other hand, when the side wall surface portion 9a of the spiral portion 7 is provided, since such interference between the lower layer flow and the upper layer flow is eliminated, a strong swirl can be obtained.

  6 and 7 show different embodiments. In the embodiment shown in FIG. 6, the downstream end of the lower flow guide tube 20 is cut obliquely so as to be substantially parallel to the top surface 16 of the combustion chamber 3. In this way, the downstream end of the lower flow guide tube 20 can be brought close to the intake valve opening region Z, so that a strong air flow toward the periphery of the combustion chamber 3 can be generated. In the embodiment shown in FIG. 7, as shown in FIG. 8, the entire length of the lower flow guide tube 20 is formed on the wall surface of the lower flow guide tube 20 located on the first side wall surface 12 side of the intake air inflow passage portion 8. A slit 21 is formed to extend over.

  As described above, in the present invention, a strong swirl is generated in the combustion chamber 3 by the lower flow that flows from the lower flow guide tube 20 into the combustion chamber 3 toward the periphery of the combustion chamber 3, and the swirl 7 The amount of intake air is increased in the upper layer flow that flows into the combustion chamber 3 after turning, so that a strong swirl can be generated while achieving high filling efficiency.

It is a top view of an intake port. It is sectional drawing of the intake port seen along the II-II line of FIG. FIG. 2 is a cross-sectional view of the intake port shown in FIG. 1, wherein (A), (B), and (C) are cross-sectional views taken along lines AA, BB, and CC, respectively, in FIG. It is. It is an enlarged view of FIG. It is a perspective view of the intake port represented graphically. It is side surface sectional drawing of the intake port which shows another Example. It is side surface sectional drawing of the intake port which shows another Example. It is a perspective view of a lower layer flow guide pipe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Combustion chamber 4,5 Intake port 6 Intake valve 7 Spiral part 8 Intake air inflow passage part 9 Peripheral wall surface 10 Upper wall surface 11 Lower end outlet part 12 1st side wall surface 13 2nd side wall surface 14a 1st upper wall surface 14b 1st 2 Upper wall surface 15 Bottom wall surface 18 Valve seat 19 Intake valve opening 20 Lower layer flow guide tube X Upper layer flow channel Y Lower flow channel Z Intake valve opening region

Claims (6)

  A spiral portion formed around the axis of the intake valve, an intake air inflow passage portion extending tangentially from the spiral portion, a peripheral wall surface extending around the axis of the intake valve, an upper wall surface, A first side wall surface that is defined by a lower end outlet portion that is opened and closed by an intake valve, and the intake air inflow passage portion is tangentially connected to the peripheral wall surface of the spiral portion, and toward the valve shaft of the intake valve In the intake port of the internal combustion engine defined by the second side wall surface extending to the peripheral wall surface of the spiral portion, the upper wall surface, and the bottom wall surface, the lower end outlet portion of the spiral portion is disposed at the peripheral edge portion of the combustion chamber top surface In addition, an intake air inflow passage is disposed so that the first side wall surface extends tangentially to the peripheral edge of the combustion chamber, and is formed between the intake valve and the valve seat of the intake valve when the intake valve is fully open. Of the annular intake valve opening, the cylinder axis and the intake valve valve An intake valve opening region formed on the opposite side of the intake air inflow passage portion with respect to a plane including the central portion of the intake air flow passage exists, and the lower layer flow that flows below the intake air inflow passage portion in the intake air inflow passage portion And an upper layer flow that flows above the intake air inflow passage portion is generated, and in order to guide the lower layer flow to the intake valve opening region, from the intake air inflow passage portion across the spiral portion toward the intake valve opening region. An extended lower flow guide pipe is provided, and when the intake valve is opened, the lower flow is guided to the intake valve opening area by the lower flow guide pipe and flows from the intake valve opening area into the combustion chamber toward the periphery of the combustion chamber. An intake port of the internal combustion engine in which a swirl is generated in the combustion chamber and the upper layer flow is swirled in the spiral portion when the intake valve is opened and then dispersed from the entire intake valve opening and flows into the combustion chamber.   A first upper wall surface that is located on the first side wall surface side at least downstream of the intake air inflow passage portion and smoothly connected to the upper wall surface of the spiral portion; And a second upper wall surface positioned on the second side wall surface side and positioned on the bottom wall surface side with respect to the first upper wall surface, and the lower layer flow path through which the lower layer flow flows is the first side The upper layer flow path defined by the lower part of the wall surface, the second side wall surface, the second upper wall surface and the bottom wall surface and through which the upper layer flow flows is above the lower layer flow path and the lower layer flow path and the first wall surface. 2. The intake port of the internal combustion engine according to claim 1, wherein the intake port is formed between upper wall surfaces of the internal combustion engine and extends from the lower flow path to the intake valve opening region across the spiral portion.   The side wall surface of the spiral portion extends so as to close the downstream end of the lower layer flow path, and the lower layer flow guide tube passes through the side wall surface portion of the spiral portion blocking the downstream end of the lower layer flow path. The intake port of the internal combustion engine according to claim 2.   2. The internal combustion engine according to claim 1, wherein the intake valve opening region is in a range of approximately 90 degrees in a swirling direction of the intake air flow in the spiral portion from an intersection of the flat surface and the intake valve opening on the peripheral side of the combustion chamber. Intake port.   The intake port of an internal combustion engine according to claim 1, wherein the downstream end of the lower flow guide pipe is cut obliquely so as to be substantially parallel to the top surface of the combustion chamber.   The intake of the internal combustion engine according to claim 1, wherein a slit extending over the entire length of the lower flow guide tube is formed on a wall surface of the lower flow guide tube located on the first side wall surface side of the intake air inflow passage portion. port.

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