JP4887963B2 - Intake device for internal combustion engine - Google Patents

Description

  The present invention relates to an intake device for an internal combustion engine.

  A first intake port extending tangentially to the peripheral edge of the combustion chamber and a second intake port arranged in parallel with the first intake port, the first intake port and the second intake port An internal combustion engine in which the engine is inclined so as to gradually descend toward the combustion chamber and the inclination angle of the second intake port is larger than the inclination angle of the first intake port is known (Patent Document). 1). In this internal combustion engine, a swirl is generated in the combustion chamber by the intake air flow that flows tangentially from the first intake port to the periphery of the combustion chamber.

  On the other hand, it is constituted 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. In a helical intake port having a first side wall surface and a second side wall surface extending to the peripheral 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 above-described first wall surface. A first upper wall surface located on the side wall surface 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 lower in height than the first upper wall surface. A lower flow that flows along the bottom wall surface of the intake air inflow passage section and an upper flow that flows along the first upper wall surface are generated from the upper wall surface, with the height position of the second upper wall surface as a boundary, A helical intake port that allows swirl to be generated in the combustion chamber by this upper layer flow is public. It (see Patent Document 2).

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.
JP-A-5-106450 Japanese Utility Model Publication No. 2-147830

  By the way, if all the intake air is made to flow tangentially from the intake port to the periphery of the combustion chamber as in the internal combustion engine described in Patent Document 1, a strong swirl can be generated in the combustion chamber. However, in this case, all the intake air flowing in the intake port flows into the combustion chamber only from the opening of the intake valve located forward in the flow direction. This is substantially the same as the flow passage area of the intake valve opening being reduced, and therefore high intake efficiency is not obtained because the intake air amount is limited, and as a result, at the time of maximum load operation. The output will decrease.

  On the other hand, in the helical intake port described in Patent Document 2, swirl is generated in the combustion chamber by swirling the intake air in the spiral portion as in the conventional helical 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. As a result, the output at the maximum load operation is also lowered in this case.

That is, as described in Patent Document 1, as long as a strong swirl is obtained by tangentially flowing all the intake air flowing out from the intake port into the peripheral portion of the combustion chamber, Patent Document 2 As long as the swirl is strengthened by strengthening the swirling action in the spiral part, it is difficult to secure a strong swirl and high filling efficiency at the same time, and to ensure a strong swirl and high filling efficiency at the same time It is necessary to change the way of thinking.
The present inventor has studied the flow of intake air over a long period of time, and finally found an intake device that can simultaneously ensure a strong swirl and high filling efficiency.

That is, according to the present invention, the first intake port and the second intake port are provided, and the first intake port is formed around the axis of the intake valve, and the spiral portion is tangentially formed from the spiral portion. The intake air inflow passage portion extends, and the spiral portion is defined by a peripheral wall surface extending around the axis of the intake valve, an upper wall surface, and a lower end outlet portion opened and closed by the intake valve. A first side wall surface in which the passage portion is tangentially connected to the peripheral wall surface of the spiral portion, a second side wall surface extending to the peripheral wall surface of the spiral portion toward the valve shaft of the intake valve, an upper wall surface, and a bottom wall surface The lower end outlet of the spiral is disposed at the peripheral edge of the combustion chamber top surface, and the first side wall surface extends tangentially to the peripheral edge of the combustion chamber. An intake air inflow passage is arranged, and when the intake valve is fully open, Among the annular intake valve openings formed between the valve seats of the valve, the intake valve opening formed on the opposite side of the intake air inflow passage with respect to the plane including the cylinder axis and the central portion of the intake valve valve body A region exists, the intake valve opening region is a range of approximately 90 degrees in the swirling direction of the intake air flow in the spiral portion from the intersection of the plane and the intake valve opening on the peripheral side of the combustion chamber, A first upper wall surface that is located on the first side wall surface side and is smoothly connected to the upper wall surface of the spiral portion at least downstream of the intake air inflow passage portion; The second upper wall surface is located on the side wall surface side and located on the bottom wall surface side with respect to the first upper wall surface, and the second upper wall surface is opposite to the second upper wall surface with respect to the above-described plane. extends toward the upper edge of the intake valve opening located in the lower layer flow passage through which the lower layer flow The upper layer flow path defined by the lower portion of the first side 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 located above the lower layer flow path and the first lower flow path and the first flow path. It is formed between the upper wall surfaces, and the lower part of the first side wall surface, the second side wall surface, the second upper wall surface and the bottom wall surface are configured so that the lower layer flow path extends straight toward the intake valve opening region. The lower flow that flows below the intake air inflow passage and the upper flow that flows above the intake air inflow passage are generated in the intake air inflow passage, and the lower flow flows toward the intake valve opening area when the intake valve is opened. After flowing, the air flows into the combustion chamber from the intake valve opening region toward the periphery of the combustion chamber to generate a swirl in the combustion chamber, and the upper layer flow swirls in the spiral when the intake valve is opened and then from the entire intake valve opening. Dispersed and flows into the combustion chamber, and the first intake port and the second intake port The air port is inclined so as to gradually descend toward the combustion chamber, and the inclination angle of the second intake port is made larger than the inclination angle of the first intake port.

  A swirl is generated by the lower layer flow flowing in the lower flow path of the first intake port, and high filling efficiency is ensured by the upper flow flowing in the upper flow path. On the other hand, the intake air flow flowing in from the second intake port improves the charging efficiency without decelerating the generated swirl. As a result, a strong swirl and high filling efficiency can be secured at the same time.

  1 and 2, reference numeral 1 denotes a cylinder block, 2 denotes a cylinder head, and 3 denotes a combustion chamber. A first intake port 4 and a second intake port 5 arranged in parallel with each other are formed in the cylinder head 2, and a pair of cylinders in the cylinder head 2 are not shown in FIGS. 1 and 2. The exhaust port is formed. As can be seen from FIG. 2, the first intake port 4 and the second intake port 5 are inclined so as to gradually descend toward the combustion chamber 3, and further compared to the inclination angle of the first intake port 4. The inclination angle of the second intake port 5 is increased.

  First, the first intake port 4 will be described with reference to FIGS. 1, 3 and 5. Referring to FIGS. 1, 3, and 4, the first intake port 4 includes a spiral portion 7 formed around the axis of the intake valve 6, and an intake air inflow passage portion 8 that extends tangentially from the spiral portion 7. Consists of. As shown in FIGS. 1, 3, and 4 (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 3, 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. 3) 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 first intake port 4 and the second intake port 5. Referring to FIGS. 1 and 3 to 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. 4A to 4C and FIG. 5, the first upper wall surface 14a descends gradually toward the spiral portion 7 while the lateral width gradually increases, 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. 4A to 4C and FIG. 5, the first upper wall surface 14 a and the second upper wall surface 14 b extend substantially in the horizontal direction in 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. 3, 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. 6A shows a case where only a portion related to the lower layer flow path X of FIG. 5 is taken out, and FIG. 6B shows a case where only a portion related to the upper layer flow path Y of FIG. 5 is taken out.

  FIG. 8 shows an enlarged view of FIG. When the intake valve 6 is opened as shown in FIGS. 3 and 4C, 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, among the annular intake valve openings 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 FIG. 5, FIG. 6 (A) and FIG.
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. In the present invention, as can be seen from FIG. 5 and FIG. 6A, the lower portion of the first side wall surface 12, the second side wall surface 13, the second upper wall surface 14b and the bottom wall surface 15 are provided by the lower flow path X. It is configured to extend straight toward the opening region Z.

  Thus, the second upper wall surface 14b is positioned on the side opposite to the second upper wall surface 14b with respect to the plane K as shown in FIG. 3 so that the lower layer flow path X extends straight toward the intake valve opening region Z. It extends toward the upper edge of the intake valve opening 19. When the lower layer flow path X is formed in this way, the lower layer flow flowing in the lower layer flow path X proceeds straight in the lower layer flow path X when the intake valve 6 is opened, and then as shown by the arrow S in FIG. It flows into the combustion chamber 3 from the valve opening region Z toward the periphery of the combustion chamber 3, thereby generating a strong swirl around the cylinder axis O in the combustion chamber 3.

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, then turns in the spiral portion 7 and opens the intake valve as shown by an arrow T in FIG. Dispersed from the entire portion 19 and flows into the combustion chamber 3. Thus the intake air by flowing the whole of the intake valve opening 19 can be increased intake air amount. 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.

  Thus, in the present invention, a strong swirl is generated in the combustion chamber 3 by the lower flow that flows straight into the combustion chamber 3 from the first intake port 4 toward the periphery of the combustion chamber 3, and the spiral portion The amount of intake air is increased in the upper layer flow that flows into the combustion chamber 3 after swirling in the cylinder 7, so that a strong swirl can be generated while achieving high filling efficiency.

  Next, the second intake port 5 will be described with reference to FIGS. 1 and 7. As shown in FIG. 1, the second intake port 5 is a helical intake air having a spiral portion 21 formed around the axis of the intake valve 20 and an intake air inflow passage portion 22 extending tangentially from the spiral portion 21. Consists of ports. As shown in FIG. 7, a concave groove 23 having a slightly larger diameter than the valve body 20 a of the intake valve 20 is formed on the top surface 16 of the combustion chamber 3 that hits the outlet of the spiral portion 21. A valve body 20 a of the intake valve 20 is disposed in the concave groove 23.

  When the valve body 20a of the intake valve 20 is arranged in the concave groove 23 in this way, the intake air flow flowing out from the periphery of the valve body 20a of the intake valve 20 into the combustion chamber 3 is moved in the cylinder axial direction by the peripheral wall surface 23a of the concave groove 23. Guided. That is, the peripheral wall surface 23a of the concave groove 23 forms a mask wall for directing the intake air flow flowing out from around the valve body 20a of the intake valve 20 in the cylinder axial direction.

As described above, the first intake port 4 and the second intake port 5 are inclined so as to gradually descend toward the combustion chamber 3, and the second intake air is compared with the inclination angle of the first intake port 4. The inclination angle of the port 5 is increased. That is, in FIG. 2, the central axis of the intake air flow path portion 8 of the first intake port 4 is L ₁ , the central axis of the intake air flow path portion 22 of the second intake port 5 is L ₂ , and the cylinder axis is Assuming that the vertical reference plane is S ₀ , the suction of the second intake port 5 is larger than the angle θ ₁ formed by the central axis L ₁ of the intake air flow path portion 8 of the first intake port 4 and the reference plane S _0. The angle θ ₂ formed by the central axis L ₂ of the air flow path portion 22 and the reference plane S ₀ is increased.

  Further, as shown in FIG. 1, the intake valve 6 provided for the first intake port 4 and the intake valve 20 provided for the second intake port 5 are arranged on one side of the combustion chamber 3. The first intake port 4 and the second intake port 5 extend from the corresponding intake valves 6 and 20 in the same direction. Further, as can be seen from FIG. 1, the spiral portion 7 of the first intake port 4 and the spiral portion 21 of the second intake port 5 are formed so that the intake air flow swirls in the same direction within these spiral portions 7 and 21. ing.

As shown in FIG. 2, since the inclination angle θ ₂ of the second intake port 5 is formed large, intake air flows from the second intake port 5 downward into the combustion chamber 3. Therefore, the intake air flow flowing into the combustion chamber 3 from the second intake port 5 does not decelerate the swirl flow generated by the intake air flow flowing from the first intake port 4, and is thus charged. A powerful swirl flow can be secured while increasing efficiency.

  Furthermore, in the embodiment according to the present invention, since the mask wall 23a is provided for the intake air flow flowing into the combustion chamber 3 from the second intake port 5, this intake air flow is more reliably guided in the cylinder axial direction. The Therefore, interference between the intake air flow flowing in from the second intake port 5 and the swirl flow can be further avoided.

  Further, in the embodiment according to the present invention, the intake air flowing into the combustion chamber 3 from the second intake port 5 is the intake air flow flowing from the first intake port 4 as shown by the arrow V in FIGS. While swirling in the same direction as the swirling direction T, it goes downward of the combustion chamber 3 and then swirls in the same direction under the swirl flow generated by the intake air flow from the first intake port 4. Thus, a swirl flow is generated in the upper region in the combustion chamber 3 by the intake air flow from the first intake port 4, and also in the lower region in the combustion chamber 3 by the intake air flow from the second intake port 5. Since a swirl flow is generated, a powerful swirl can be obtained.

It is a top view of an intake port. FIG. 2 is a side view of the intake port schematically shown along arrow II in FIG. 1. FIG. 3 is a cross-sectional view of a first intake port taken along line III-III in FIG. 1. FIG. 2 is a cross-sectional view of the first intake port shown in FIG. 1, wherein (A), (B), and (C) are taken along lines AA, BB, and CC, respectively, in FIG. 1. FIG. It is a perspective view of the intake port represented graphically. It is a figure which shows the lower layer flow path X and the upper layer flow path Y. It is sectional drawing of the 2nd intake port seen along the VII-VII line of FIG. It is an enlarged view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Combustion chamber 4 1st intake port 5 2nd intake port 6,20 Intake valve 7,21 Swirl part 8,22 Intake air inflow passage part 9 Peripheral wall surface 10 Upper wall surface 11 Lower end exit part 12 1st side wall surface 13 Second side wall surface 14a First upper wall surface 14b Second upper wall surface 15 Bottom wall surface 18 Valve seat 19 Intake valve opening X Upper layer flow path Y Lower flow path Z Intake valve opening area

Claims (5)

A spiral portion having a first intake port and a second intake port, wherein the first intake port is formed around the axis of the intake valve, and an intake air inflow passage portion extending tangentially from the spiral portion The swirl portion is defined by a peripheral wall surface extending around the axis of the intake valve, an upper wall surface, and a lower end outlet portion opened and closed by the intake valve, and the intake air inflow passage portion is swirled. Defined by a first side wall surface tangentially connected to the peripheral wall surface of the part, a second side wall surface extending to the peripheral wall surface of the spiral portion toward the valve shaft of the intake valve, an upper wall surface, and a bottom wall surface In the internal combustion engine, the lower end outlet portion of the spiral portion is disposed at a peripheral portion of the top surface of the combustion chamber, and the intake air is disposed such that the first side wall surface extends tangentially to the peripheral portion of the combustion chamber. An inflow passage is arranged, and when the intake valve is fully open, the intake valve and intake valve Among the annular intake valve openings formed between the seats, there is an intake valve opening region formed on the opposite side of the intake air inflow passage with respect to the plane including the cylinder axis and the center of the intake valve valve body. The intake valve opening region is in a range of approximately 90 degrees in the swirling direction of the intake air flow in the spiral portion from the intersection of the plane and the intake valve opening on the peripheral side of the combustion chamber. A first upper wall surface that is located on the first side wall surface side and is smoothly connected to the upper wall surface of the spiral portion at least downstream of the intake air inflow passage portion; And a second upper wall surface located on the bottom wall surface side of the first upper wall surface, the second upper wall surface being the second upper wall surface with respect to the plane. opposite it extends toward the upper edge of the intake valve opening located in the lower layer flow stream and The lower layer channel is defined by the lower part of the first side wall surface, the second side wall surface, the second upper wall surface and the bottom wall surface, and the upper layer channel through which the upper layer flow flows is located above the lower layer channel. The lower channel is formed between the lower channel and the first upper wall surface, and the lower portion of the first side wall surface, the second side wall surface, the second upper wall surface, and the bottom wall surface are connected to the lower channel channel. Is configured to extend straight toward the intake valve opening region, and the lower flow flows toward the intake valve opening region when the intake valve is opened and then flows from the intake valve opening region into the combustion chamber. Flowing in the peripheral direction to generate a swirl in the combustion chamber, the upper layer flow swirls in the swirl when the intake valve is opened, and then dispersed from the entire intake valve opening and flows into the combustion chamber, and the first intake air Inclined so that the port and the second intake port are gradually lowered toward the combustion chamber An intake device for an internal combustion engine in which the inclination angle of the second intake port is larger than the inclination angle of the first intake port. An intake valve provided for the first intake port and an intake valve provided for the second intake port are disposed on one side of the combustion chamber, and the first intake port and the second intake port are provided. The intake device for an internal combustion engine according to claim 1 , wherein the intake port extends in the same direction from the corresponding intake valve . The second intake port is a helical intake port having 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 spiral portion of the first intake port 2. The intake device for an internal combustion engine according to claim 1 , wherein the vortex portions of the second intake port and the second intake port are formed so that the intake air flow swirls in the same direction in the vortex portions . 2. A mask wall for directing an intake air flow flowing out from the periphery of the valve body of the intake valve in a cylinder axial direction is formed around the valve body of the intake valve provided for the second intake port. An intake device for an internal combustion engine according to claim 1. An intake valve provided for the second intake port is disposed in a groove formed on the top surface of the combustion chamber, and a peripheral wall surface of the groove forms the mask wall. 5. An intake device for an internal combustion engine according to 4 .

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