JP2018128003A - engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increase in temperature of intake air in an intake port, and to achieve smooth fuel vaporization in the intake port.SOLUTION: An engine 1 includes an intake port 3 and an exhaust port 4 connected to a combustion chamber 2 of the engine 1, a fuel injection valve 10 disposed in the intake port 3 and injecting fuel, and a partition wall 11 partitioning an inside of the intake port 3 into an upper port 16 and a lower port 13. A heat insulating material 12 is arranged on an inner surface of the upper port 16, and the fuel injection valve 10 is disposed in the lower port 13. A flow regulating valve A is provided on the upstream side in an intake flow direction of the fuel injection valve 10 in the lower port 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an engine having an intake passage structure that enables good combustion in a combustion chamber.

  Intake air is supplied into the combustion chamber of the engine through an intake passage (hereinafter referred to as an intake port) provided in an intake manifold or a cylinder head. In addition, a fuel injection valve is provided in the intake port, and the fuel injected from the fuel injection valve diffuses in the combustion chamber together with the intake air, and the diffused fuel is ignited and burned by an ignition plug provided in the combustion chamber. To do.

  By the way, if heat generated by the combustion of fuel in the combustion chamber is transmitted to the intake port side and the temperature of the intake air rises excessively, it may cause a decrease in intake charging efficiency and occurrence of knocking.

  Thus, for example, Patent Document 1 discloses a technique for suppressing a rise in the temperature of intake air by disposing a heat insulating material having low thermal conductivity on the inner surface of the intake port. In this technique, the inside of the intake port is divided into an upper passage and a lower passage by a partition, and a control valve that controls the amount of air is provided in the lower passage. The heat insulating material is arrange | positioned at the inner surface of the upper channel | path including the surface by the side of the upper channel | path of a partition.

  Similarly, in Patent Document 2, the inside of the intake port is divided into an upper passage and a lower passage by a partition, and a control valve that controls the amount of air is provided in the lower passage, and the thermal conductivity is provided on the surface of the partition on the upper passage side. There is disclosed a technique in which a high heat conductive material is disposed and a heat insulating material is disposed on a surface of the partition wall on the lower passage side.

Japanese Unexamined Patent Publication No. 2007-71129 (refer to FIG. 14 on page 16, etc.) JP 2010-174722 A

  When the heat insulating material is disposed in the intake port as described above, the intake air temperature is lowered and the intake charge efficiency can be improved, and the ignition advance is also possible. However, since the wall surface temperature of the intake passage is reduced by arranging the heat insulating material, it is considered that the smooth vaporization of the injected fuel may be hindered depending on the operation state. It is desirable that fuel vaporization is always smooth.

  Therefore, an object of the present invention is to suppress a rise in the temperature of intake air in the intake port and to realize smooth vaporization of fuel in the intake port.

  In order to solve the above problems, the present invention includes an intake port and an exhaust port connected to a combustion chamber of an engine, a fuel injection valve disposed in the intake port and injecting fuel, and an upper portion in the intake port. A partition wall separating the port and the lower port, a heat insulating material is disposed on the inner surface of the upper port, the fuel injection valve is disposed in the lower port, and is more in the intake flow direction than the fuel injection valve of the lower port An engine equipped with a flow control valve on the upstream side was adopted.

  Here, the flow rate adjusting valve includes a valve shaft disposed in a direction intersecting an intake flow direction in the intake port, and a valve body rotatable around the valve shaft, The structure supported by the upstream edge part of the suction flow direction of a partition can be employ | adopted.

  Alternatively, the flow rate adjusting valve includes a valve shaft disposed in a direction intersecting an intake flow direction in the intake port, and a valve body rotatable around the valve shaft, and the valve shaft includes the partition wall The structure supported by the said partition which becomes a predetermined distance downstream from the upstream edge part of this can be employ | adopted.

  At this time, the valve body includes a base portion supported by the valve shaft, and a valve tip portion that abuts against a bottom portion of the lower port in a valve-closed state, and the valve tip portion is the valve shaft in a valve-closed state. It is possible to adopt a configuration that is located upstream of the intake flow direction.

  Further, as another aspect of the flow rate adjusting valve, the flow rate adjusting valve includes a valve shaft disposed in a direction intersecting an intake flow direction in the intake port, and a valve body rotatable around the valve shaft. The valve shaft can be configured to be supported on the bottom of the lower port.

  At this time, the valve body includes a base portion supported by the valve shaft, and a valve tip portion that comes into contact with the top surface of the lower port in a closed state, and the valve tip portion is in the closed state. A configuration that is located downstream of the shaft in the intake flow direction can be employed.

  In each of these aspects, the partition can adopt a configuration in which the heat capacity of the member per unit area gradually decreases toward the downstream side in the intake flow direction.

  For example, the partition may be configured such that the thickness of the member is gradually reduced toward the downstream side in the intake flow direction. Alternatively, for example, the partition has a hollow portion inside, and the hollow portion adopts a configuration in which the volume interposed in the partition per unit area gradually increases toward the downstream side in the intake flow direction. be able to.

  The present invention includes an upper port and a lower port through a partition wall in the intake port, a heat insulating material is disposed on the inner surface of the upper port, a fuel injection valve is disposed in the lower port, and the fuel injection valve of the lower port is A flow control valve is provided upstream in the intake flow direction, so adjusting the inflow of intake air to the lower port suppresses the rise in intake air temperature in the intake port and smoothes the fuel vaporization in the intake port. Can be realized.

It is sectional drawing which shows embodiment of this invention. It is sectional drawing when the flow regulating valve of FIG. 1 will be in a valve closing state. (A) (b) is sectional drawing which shows other embodiment. (A) and (b) are sectional views showing other embodiments, respectively. (A) (b) (c) is sectional drawing which shows further another embodiment, respectively.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing the vicinity of a combustion chamber 2 and a cylinder head of an engine 1 of this embodiment. FIG. 2 is a cross-sectional view of the intake port 3.

  As shown in FIG. 1, a piston 8 is accommodated in the cylinder of the engine 1. The combustion chamber 2 is formed by the upper surface of the cylinder, the inner peripheral surface, the upper surface of the piston 8, and the like. An upper cylinder head of the combustion chamber 2 is provided with an intake port 3 for sending intake air into the combustion chamber 2 and an exhaust port 4 drawn from the combustion chamber 2.

  In addition, a fuel injection valve (injector) 10 for injecting fuel into the combustion chamber 2 and the intake port 3 is provided in the intake port 3. An ignition device 7 is provided at the top of the combustion chamber 2 to generate an ignition spark that burns fuel supplied into the combustion chamber 2.

  An intake valve hole that is an opening of the intake port 3 to the combustion chamber 2 is opened and closed by the intake valve 5. Similarly, an exhaust valve hole that is an opening of the exhaust port 4 to the combustion chamber 2 is also opened and closed by the exhaust valve 6.

  In these drawings, members and means on the intake side that are directly related to the present invention are mainly shown, and other members and the like are not shown. Although only one cylinder is shown in the drawings, the engine 1 may be a single cylinder or a multi-cylinder having a plurality of cylinders.

  The cross-sectional shape of the intake port 3 is a so-called horizontally long oval shape in which the maximum diameter in the vertical direction connecting the upper surface 3a side and the lower surface 3b side of the passage is set smaller than the maximum diameter in the width direction perpendicular thereto. It has become. Such an oval shape is a portion where the valve head 5b extending from the umbrella portion 5a of the intake valve 5 is supported by the cylinder head from the intake passage in the intake manifold arranged upstream of the intake port 3 in the intake flow direction. It continues in the section up to the vicinity of the valve support.

  A partition wall 11 that divides the space in the intake port 3 into an upper port 16 and a lower port 13 is provided upstream of the intake valve 5 in the intake port 3 in the intake flow direction. The partition wall 11 is provided in a range of a certain length from the upstream end portion 11d to the downstream end portion 11e with respect to the intake flow direction connecting the upstream side and the downstream side of the intake port 3.

  The partition wall 11 may be a plate-like member that linearly connects the inner walls in the width direction of the passage. In addition, the partition wall 11 has an arc shape between the inner walls in the width direction of the passage along the lower surface 3b of the intake port 3. It may be a plate-like member or the like.

  A heat insulating material 12 is disposed on the inner surface of the upper port 16. The heat insulating material 12 is disposed on the entire inner surface of the upper port 16 including the surface of the partition wall 11 on the upper port 16 side. The heat insulating material 12 is also disposed on the inner surface of the intake port 3 upstream of the upstream end portion 11 d of the partition wall 11. The heat insulating material 12 is not disposed on the inner surface of the lower port 13, and the metal that is the material of the partition wall 11 and the intake port 3 is exposed on the inner surface of the lower port 13.

  The material constituting the members of the partition wall 11 and the intake port 3 is usually made of an aluminum alloy, but it can be made of other metals or other materials. Further, the partition wall 11 and the intake port 3 can be made of different materials, but it is desirable that the thermal conductivity of the both be the same. The material of the heat insulating material 12 is a material whose thermal conductivity is relatively lower than the members of the partition wall 11 and the intake port 3, and for example, a resin or the like can be adopted.

  The fuel injection valve 10 disposed in the intake port 3 is disposed in the lower port 13. The fuel injection valve 10 is disposed so that the injection port faces the space in the lower port 13 from the lower surface 3b side of the intake port 3.

  A vehicle equipped with the engine 1 includes an electronic control unit 20. The electronic control unit 20 controls the engine 1 and all the auxiliary equipment including the opening / closing control of the intake and exhaust valves 5 and 6, the control of fuel injection, the control of the ignition timing by the ignition device 7, and the like. Also controls the equipment.

  In the lower port 13, the fuel is injected from the injection port of the fuel injection valve 10 toward the downstream side along the intake flow direction. The fuel injected from the fuel injection valve 10 is supplied to the combustion chamber 2. Further, since fuel is not injected in the upper port 16, air from the upstream side is supplied to the combustion chamber 2.

  Here, in the lower port 13, a flow rate adjustment valve A is provided upstream of the fuel injection valve 10. In this embodiment, the flow rate adjustment valve A is arranged at the upstream end of the lower port 13 so that the amount of intake air (fresh air) flowing into the lower port 13 from the upstream side can be adjusted. FIG. 1 shows the opened state of the flow regulating valve A, and FIG. 2 shows the closed state of the flow regulating valve A.

  As described above, since the heat insulating material 12 is arranged on the inner surface of the upper port 16 for supplying intake air, the temperature of the inner surface of the upper port 16 due to the transfer of heat from the combustion chamber 2 side, the exhaust blowback, or the like. The rise is suppressed. Thereby, the temperature rise of the intake air supplied through the upper port 16 can be suppressed. In addition, since the fuel injection valve 10 is disposed in the lower port 13 which is a non-insulated port where the heat insulating material 12 is not disposed, the inner surface of the lower port 13 transmits heat from the combustion chamber 2 side or exhausts. By blowing back, etc., it is maintained at an appropriate temperature higher than the inner surface of the upper port 16, and smooth vaporization of fuel in the intake port 3 can be realized. Furthermore, since the flow regulating valve A is provided upstream of the fuel injection valve 10 in the lower port 13, the temperature of the inner surface of the lower port 13 can be prevented by adjusting the inflow of intake air to the lower port 13. This can further promote fuel vaporization.

  During normal operation, it is desirable that the valve body 15 of the flow rate adjustment valve A is fully closed to keep the inside of the lower port 13 warm. Further, it is desirable that the valve body 15 of the flow rate adjustment valve A is fully opened to ensure a necessary intake air amount during full load.

  The specific configuration of the flow rate adjusting valve A in this embodiment includes a valve shaft 14 disposed in a direction intersecting the intake flow direction in the intake port 3 and a valve body 15 that is rotatable around the valve shaft 14. I have. The valve shaft 14 is supported by the upstream end portion 11d of the partition wall 11, and the axial direction thereof is a direction orthogonal to the intake flow direction.

  In the valve open state shown in FIG. 1, the plate-like valve body 15 extends on the same straight line extending the direction of the partition wall 11 from the upstream end 11d of the partition wall 11 toward the upstream side. The flow of intake air from the side is smoothly guided to the upper port 16 and the lower port 13 without resistance.

  2, the plate-like valve body 15 is smoothly connected from the lower surface 3b of the intake port 3 toward the upstream end portion 11d of the partition wall 11, so that the intake air from the upstream side Is smoothly guided to the upper port 16.

  Here, in the cross section orthogonal to the intake flow direction of the intake port 3, the cross sectional area of the upper port 16 is set to be the same as or larger than the cross sectional area of the lower port 13. Since the upper port 16 functions as a main intake passage and the lower port 13 functions as a passage for supplying fuel, preferably, the cross-sectional area of the upper port 16 is several times larger than the cross-sectional area of the lower port 13 (for example, 2 to 2). It should be set larger.

  In the embodiment of FIGS. 3A and 3B, the valve shaft 14 of the flow rate adjusting valve A is supported by the bottom 13b of the lower port 13 on the downstream side of the upstream end 11d of the partition wall 11. The valve body 15 includes a base portion 15a supported by the valve shaft 14 and a valve tip portion 15b that contacts the top surface 13a of the lower port 13 on the downstream side of the valve shaft 14 in the closed state. .

For this reason, when the flow rate adjustment valve A is opened, FIG.
As shown by the arrow a in (b), the intake air passing through the side closer to the partition wall 11 increases. For this reason, the fuel injected from the fuel injection valve 10 flows in a layered manner along the bottom portion 13b on the side far from the partition wall 11, as indicated by the arrow b in the figure. The amount of adhesion to the top surface 13a) is reduced. Thereby, vaporization of fuel can be further promoted. Further, most of the intake air introduced into the combustion chamber 2 reaches the combustion chamber 2 through the side close to the bottom portion 13 b of the lower port 13, so that more fuel is introduced into the intake side than in the exhaust side in the combustion chamber 2. Will come to be.

  Next, in the embodiment shown in FIG. 4A, the valve shaft 14 of the flow regulating valve A is supported by the bottom 13 b of the lower port 13 on the upstream side of the upstream end 11 d of the partition wall 11. In addition, the valve tip 15b of the valve body 15 contacts the upstream end 11d of the partition wall 11 on the downstream side of the valve shaft 14 in the closed state.

  Also in this embodiment, as in FIG. 2, in the valve-closed state, the plate-like valve body 15 is smoothly connected from the lower surface 3b of the intake port 3 toward the upstream end 11d of the partition wall 11. The flow of intake air from the upstream side is smoothly guided to the upper port 16.

  In the embodiment shown in FIG. 4B, the valve shaft 14 of the flow rate adjustment valve A is supported by the partition wall 11 on the downstream side of the upstream end portion 11 d of the partition wall 11. In addition, the valve tip 15b of the valve body 15 contacts the bottom 13b of the lower port 13 on the upstream side of the valve shaft 14 in the closed state.

  For this reason, when the flow regulating valve A is opened, the intake air passing through the vicinity of the bottom portion 13b on the side far from the partition wall 11 in the cross section of the flow path of the lower port 13 increases. For this reason, it is unlikely that the airflow is disturbed in the vicinity of the upstream end portion 11 d of the partition wall 11, and the effect that intake air is easily guided to the lower port 13 can be expected.

  Further, in each of these embodiments, the heat capacity of the member per unit area gradually (the heat capacity of the member in a range corresponding to the unit area of the plate surface of the partition wall 11) as the partition wall 11 is moved downstream in the intake flow direction. It can be set to be smaller. Such a partition wall 11 can be employed in any embodiment in which the position and direction of the flow rate adjustment valve A are different.

  If such a partition wall 11 is employed, in the downstream area where the heat capacity is small, the partition wall 11 rises in temperature early due to heat transfer from the combustion chamber 2 side, exhaust blowback, or the like. . For this reason, the fuel can be vaporized more smoothly. In the upstream area where the heat capacity is large, it takes a long time for the temperature to rise, but once the temperature rises, the temperature is maintained at a higher level for a relatively longer time than the downstream area. Easy to be. For this reason, the effect of keeping warm so that the inner surface temperature of the lower port 13 may not be lowered can be expected.

  For example, in the embodiment of FIG. 5A, the partition wall 11 is configured such that the thickness of the member gradually decreases toward the downstream side. For this reason, in the downstream area where the plate thickness is relatively small, the heat capacity per unit area of the members constituting the partition wall 11 is small, and in the upstream area where the plate thickness is relatively thick, the partition wall 11 is formed. The heat capacity per unit area of the member to be performed is increased.

  In the embodiment of FIG. 5B, similarly, the partition wall 11 is set so that the heat capacity of the member per unit area gradually decreases toward the downstream side. Here, the partition wall 11 is configured such that the thickness of the member is gradually reduced toward the downstream side. That is, in the embodiment of FIG. 5A, the plate thickness of the partition wall 11 is continuously reduced from the upstream side to the downstream side, whereas in the embodiment of FIG. The plate thickness is gradually reduced from the upstream side toward the downstream side.

  In the downstream area where the plate thickness is relatively thin, the members constituting the partition wall 11 are formed of a single plate material called the first member 11a. In the upstream area where the plate thickness is relatively thick, the members constituting the partition wall 11 are composed of two plate members, a first member 11a and a second member 11b. Here, two types of plate thickness areas are set from the upstream side to the downstream side, but the areas with different plate thicknesses are set to, for example, three types, four types, etc., and the number of stages of plate thickness change is increased. Also good.

  In the embodiment of FIG. 5C, similarly, the partition wall 11 is set so that the heat capacity of the member per unit area gradually decreases toward the downstream side. Here, the partition wall 11 has a hollow portion 11c therein, and the hollow portion 11c is set so that the volume interposed per unit area of the partition wall 11 gradually increases toward the downstream side. That is, the member constituting the partition wall 11 is set so that the weight of the member per unit area gradually decreases toward the downstream side, and as a result, the heat capacity of the member per unit area decreases.

  Specifically, in the embodiment of FIG. 5C, in the downstream area where the hollow portion 11c is interposed, the heat capacity per unit area is small, and in the upstream area where the hollow portion 11c is not interposed. Has a large heat capacity per unit area, and two types of heat capacities are set according to the area. For example, the number of stages of change in heat capacity may be increased, such as three stages, four stages, and the like.

  Furthermore, for example, a plurality of hollow portions 11c are arranged at equal intervals along the length direction (intake flow direction in the intake port 3) and the width direction of the partition wall 11, and one of the plurality of hollow portions 11c exists. A configuration is conceivable in which the per unit volume is gradually increased from the upstream side toward the downstream side. Or the structure which changes so that the arrangement | positioning space | interval of the hollow part 11c which exists in multiple numbers and the same shape and the same magnitude | size may gradually become dense from the upstream to the downstream may be considered.

DESCRIPTION OF SYMBOLS 1 Engine 2 Combustion chamber 3 Intake port 4 Exhaust port 5 Intake valve 5a Umbrella part 5b Valve stem 6 Exhaust valve 7 Ignition device 8 Piston 10 Fuel injection valve 11 Partition 11a First member 11b Second member 11c Hollow part 11d Upstream end part 11e Downstream end 12 Heat insulating material 13 Lower port 13a Top surface 13b Bottom 14 Valve shaft 15 Valve body 15a Base 15b Valve tip 16 Upper port 20 Electronic control unit A Flow control valve

Claims (9)

An intake port and an exhaust port connected to the combustion chamber of the engine;
A fuel injection valve disposed in the intake port for injecting fuel;
A partition wall separating the intake port into an upper port and a lower port;
With
A heat insulating material is disposed on the inner surface of the upper port;
The fuel injection valve is disposed in the lower port;
An engine comprising a flow rate adjustment valve upstream of the fuel injection valve in the lower port in the intake flow direction. The flow rate adjusting valve includes a valve shaft disposed in a direction intersecting an intake flow direction in the intake port, and a valve body rotatable around the valve shaft,
The engine according to claim 1, wherein the valve shaft is supported at an upstream end of the partition wall in the intake flow direction. The flow rate adjusting valve includes a valve shaft disposed in a direction intersecting an intake flow direction in the intake port, and a valve body rotatable around the valve shaft,
2. The engine according to claim 1, wherein the valve shaft is supported by the partition wall that is downstream by a predetermined distance from an upstream end portion of the partition wall in an intake flow direction. The valve body includes a base portion supported by the valve shaft, and a valve tip portion that abuts against a bottom portion of the lower port in a closed state,
The engine according to claim 2 or 3, wherein the valve tip is positioned upstream of the valve shaft in the intake flow direction in a closed state. The flow rate adjusting valve includes a valve shaft disposed in a direction intersecting an intake flow direction in the intake port, and a valve body rotatable around the valve shaft,
The engine according to claim 1, wherein the valve shaft is supported by a bottom portion of the lower port. The valve body includes a base that is supported by the valve shaft, and a valve tip that contacts the top surface of the lower port when the valve is closed,
The engine according to claim 5, wherein the valve tip portion is located downstream of the valve shaft in the intake flow direction in a valve-closed state. The engine according to any one of claims 1 to 6, wherein the heat capacity of the member per unit area is gradually reduced toward the downstream side in the intake flow direction. The engine according to claim 7, wherein the partition wall gradually decreases in thickness toward the downstream side in the intake flow direction. The partition has a hollow portion inside,
The engine according to claim 7, wherein the volume of the hollow portion that is interposed in the partition wall per unit area gradually increases toward the downstream side in the intake air flow direction.

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