JP2007278166A - Intake device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake device for an internal combustion engine capable of reducing fuel spray adhering on a cylinder wall, improving combustibility of air fuel mixture, and reducing hydrocarbon emission. <P>SOLUTION: The intake device 1 for the internal combustion engine is provided with a plurality of intake valves 4a, 4b per a cylinder 3, and an injector 9 injecting fuel into the intake port 2. A tip part of an intake port 2 per the intake valve is divided by a bulkhead 7. A deflection plates 11a, 11b deflecting intake air flow to make intake air flow velocity relatively high at a center part of a combustion chamber and relatively low at a circumference part of the combustion chamber are provided on an upstream side of the bulkhead 7 of the intake port 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an intake device for an internal combustion engine, and more particularly, to an intake device for an internal combustion engine that can easily direct fuel spray to a central portion of a cylinder.

In the combustion of an internal combustion engine, the presence of gas flow in the air-fuel mixture has an effect of improving the combustion speed, and is effective for improving fuel efficiency and the lean combustion limit. As a conventional technique for generating turbulent flow in such an air-fuel mixture, for example, an upper and lower partition that partitions an intake port up and down is provided, and an intake control valve that opens and closes a flow path downward (crankshaft direction) from the upper and lower partition (For example, Patent Document 1). According to this prior art, by reducing the opening of the intake control valve at the time of partial load, the intake air from above the partition forms a vertical vortex (tumble) in the cylinder to improve the combustion speed, and at the time of full load It is possible to suppress an increase in intake resistance by fully opening the intake control valve.
JP 2004-308473 A (page 6, FIG. 1, FIG. 2)

  However, in the above prior art, since the upper and lower partition walls are formed deep inside the intake port, the gas flow near the center of the intake valve is slow, while the upward direction of the intake valve (in the direction opposite to the crankshaft) tends to be fast. is there. On the other hand, since the fuel injection direction is directed to the outside of each of the two intake valves, the port wall flow flows into the cylinder from the outside of the intake passage when the intake valve is opened, and the fuel adhering to the cylinder wall increases. There was a problem of doing.

  Further, since the gas flow rate inside the intake passage (the central partition wall dividing the intake passage into each valve) is reduced, the fuel spray that reaches the vicinity of the spark plug 2 due to the shearing force generated when passing through the opening of the intake valve. There was a problem that the next atomization could not be expected and it was difficult to improve the combustibility.

  The present invention has been made to solve the above-mentioned problems, and its object is to reduce fuel spray adhering to the cylinder wall, improve the combustibility of the air-fuel mixture, and reduce hydrocarbon emissions. It is an object to provide an intake device for an internal combustion engine.

  In order to achieve the above object, an intake device for an internal combustion engine according to the present invention is an intake device for an internal combustion engine comprising a plurality of intake valves per cylinder and a fuel injection valve for injecting fuel into the intake port. For each valve, the tip of the intake port is branched by a partition, and the intake flow velocity is relatively high in the center of the combustion chamber and relatively low in the periphery of the combustion chamber on the upstream side of the partition of the intake port. A deflecting plate for deflecting the intake air flow is provided. According to such an aspect, since the fuel spray injected from the fuel injection valve can be easily directed to the center of the combustion chamber, the amount of fuel adhering to the cylinder wall surface is reduced, and as a result, the combustibility is improved. And the reduction of exhaust hydrocarbons.

  For example, when there are two intake valves, the intake port front end portion is branched into two by the central partition, and each becomes a valve seat portion of the intake valve. By providing a deflector plate that changes the intake flow to the central partition side upstream of the central partition of the intake port, the intake flow velocity on the central partition side of each intake valve is increased, and fuel spray is easily placed in the center of the combustion chamber. Can be oriented.

  In order to achieve the above object, in the intake device for an internal combustion engine according to the present invention, the deflection plate deflects in the intake valve arrangement direction as it proceeds from the intake port upstream to the downstream. According to such an aspect, when there are two intake valves, since the intake valves are arranged on the left and right when viewed from the intake port, the intake valves are deflected in the left-right direction, which is the intake valve arrangement direction, as they proceed from the upstream side to the downstream side. By providing the deflection plate, the intake air flow rate can be increased at the center of the combustion chamber.

  In order to achieve the above object, an intake device for an internal combustion engine according to the present invention can be provided with two deflection plates for each partition wall. According to such an aspect, when there are two intake valves, two deflection plates that curve toward one central partition are provided. Also, when there are three intake valves, the tip of the intake port branches into three by two partition walls, and each becomes the valve seat part of the intake valve. Four deflecting plates can be provided to deflect the intake air flow toward the partition wall.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  1A and 1B are diagrams for explaining one cylinder of a four-valve internal combustion engine equipped with an intake device for an internal combustion engine according to a first embodiment of the present invention. FIG. 1A is a partial longitudinal sectional view, and FIG. 1B is a schematic plan view. is there. As shown in FIGS. 1A and 1B, the internal combustion engine includes an intake device 1, a cylinder 3, and exhaust valves 5a and 5b.

  The intake device 1 holds an intake port 2, two intake valves 4 a and 4 b, a central partition wall 7 that branches the tip of the intake port 2 to each intake valve opening / closing portion, and a slidable intake valve. The valve guide 8, the injector (fuel injection valve) 9 for injecting fuel into the intake port, the deflection plates 11a and 11b arranged on the upstream side of the central partition, and the deflection plates 11a and 11b are fixed to the intake port wall surface. And a deflection plate support 12.

  The deflecting plates 11a and 11b are formed so as to bend inwardly from the upstream side of the intake port to the downstream side so that the flow velocity of the intake flow increases on the inside of the two intake valves, that is, on the central partition wall 7 side. As a result, the flow velocity of the air or air-fuel mixture sucked from the intake port 2 into the cylinder 3 becomes relatively high at the center of the cylinder 3.

  FIG. 2 is a diagram comparing the air flow velocity distribution for each intake valve portion between the present embodiment and the conventional example in an internal combustion engine having two intake valves. FIG. 3 is a schematic diagram of the intake flow velocity distribution in an internal combustion engine having two intake valves. (A) Conventional general example (straight intake port), (b) Conventional example described in Patent Document 1 (for tumble control) (C) This is the present embodiment.

  As shown in FIG. 3A, in the case of a straight intake port having no upper and lower partition walls, deflecting plates, or the like in the intake port, it is considered that the intake flow velocity is uniform. As shown in FIG. 3B, when the upper and lower partition walls 14 are provided in the intake port, the air resistance by the upper and lower partition walls 14 and turbulent flow are generated on the downstream side of the upper and lower partition walls 14, so that the upper and lower portions of the intake valves 4a and 4b Thus, the intake flow velocity becomes relatively fast, and the intake flow velocity becomes relatively slow at the center of the intake valves 4a, 4b.

  In this embodiment, as shown in FIG. 3C, the intake air is deflected toward the central partition 7 by the deflecting plates 11a and 11b, so that a wide range of intake high-speed portions 15 are provided inside the intake valves 4a and 4b. It is formed.

  FIG. 4 is a diagram for explaining the difference in fuel spray shape between (a) the prior art and (b) this embodiment in an internal combustion engine having two intake valves. It is the same that any injector uses a two-hole type injector having two injection holes for spraying fuel on the two intake valves. However, in the prior art of FIG. 4A, the spray center line 16 of the spray injected from each nozzle is directed to the stem 13 of each intake valve 4a, 4b, whereas FIG. In this embodiment, the spray center line 16 is directed to the inside of each intake valve 4a, 4b, that is, closer to the central partition. Therefore, the angle β formed by the two spray center lines 16 in the embodiment is narrower than the angle α formed by the two spray center lines 16 in the prior art.

  FIG.4 (c) is a figure which shows typically the range of the spray direction angle in an Example. The spray direction angle is an angle formed by the spray center line with respect to the axial center line of the injector, and the right side in the figure is a wide angle and the left side is a narrow angle. The angle is larger than the angle at which the fuel spray does not interfere with the central partition wall 7.

  FIG. 5 is a schematic plan view illustrating one cylinder of a five-valve internal combustion engine equipped with an intake system for an internal combustion engine according to a second embodiment of the present invention. Since the partial cross-sectional view is substantially the same as FIG.

  As shown in FIG. 5, the internal combustion engine includes an intake device 1, a cylinder 3, and exhaust valves 5 a and 5 b. The intake device 1 is disposed on the upstream side of the partition, the intake port 2, the three intake valves 4a, 4b, and 4c, the partition walls 7a and 7b that branch the tip of the intake port 2 to the respective intake valve opening / closing sections. Deflection plates 11a, 11b, 11c, and 11d.

  The deflecting plates 11a and 11b are formed to bend from the upstream side to the downstream side of the intake port so that the flow velocity of the intake flow is deflected toward the partition wall 7a and becomes faster. Similarly, the deflection plates 11c and 11d are formed so as to bend from the upstream side to the downstream side of the intake port so that the flow velocity of the intake flow is deflected toward the partition wall 7b and becomes faster. As a result, the flow velocity of the air or air-fuel mixture sucked into the cylinder 3 from the intake port 2 becomes relatively high at the center of the cylinder 3, and the same effect as in the case of the two-intake valve of the first embodiment can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS (a) The partial longitudinal cross-sectional view of the 4-valve internal combustion engine provided with Example 1 of the intake device of the internal combustion engine which concerns on this invention, (b) The plane schematic diagram. It is a figure which compares the air flow velocity distribution for every intake valve site | part of the present Example and conventional example in the internal combustion engine provided with two intake valves. It is a schematic diagram of the intake flow velocity distribution in an internal combustion engine provided with two intake valves, (a) conventional example (straight intake port), (b) conventional example described in Patent Document 1 (up and down intake port for tumble control) (Partition wall), (c) This example. It is a figure explaining the difference in the fuel spray shape of (a) prior art and (b) a present Example in the internal combustion engine provided with two intake valves. FIG. 6 is a schematic plan view for explaining a 5-valve internal combustion engine equipped with an intake system for an internal combustion engine according to a second embodiment of the present invention.

Explanation of symbols

1: Intake device 2: Intake port 3: Cylinder 4a, 4b: Intake valve 5a, 5b: Exhaust valve 6: Spark plug mounting hole 7: Central partition wall 8: Valve guide 9: Injector (fuel injection valve)
10: Fuel spray 11a, 11b: Deflection plate 12: Deflection plate support

Claims (3)

An internal combustion engine that includes a plurality of intake valves for opening and closing each opening and a fuel injection valve for injecting fuel into the intake port. An engine intake system,
A deflection plate is provided on the upstream side of the partition wall of the intake port to deflect the intake air flow so that the intake air flow velocity is relatively high in the center of the combustion chamber and the intake air flow velocity is relatively low in the periphery of the combustion chamber. An intake device for an internal combustion engine.   2. The intake device for an internal combustion engine according to claim 1, wherein the deflecting plate deflects in an intake valve arrangement direction as the intake port proceeds from upstream to downstream.   The intake device for an internal combustion engine according to claim 1 or 2, wherein the deflecting plate is provided with two deflecting plates for each partition wall.

Images