JP2016114021A - Internal combustion engine intake port heat insulation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fuel economy while ensuring the smooth fuel injection operation of an injector.SOLUTION: An intake port 30 is constituted by a heat insulation member 44 having a wall surface which is partially attached to a cylinder head 16. The heat insulation member 44 comprises a generally cylindrical upstream wall part 44A located upstream of a nozzle hole 4208; and a semi-cylindrical downstream wall part 44B located downstream of the nozzle hole 4208. A notch 50 is formed in a portion, where an injector 42 is disposed, of the downstream wall part 44B for forming, by a wall surface 3006 of the cylinder head 16, a wall surface of the intake port 30 in a range to which a fuel injected from the nozzle hole 4208 of the injector 42 adheres by intake air flowing in the intake port 30 in a state of opening to a downstream end of the intake port 30. An injector accommodation part 52 accommodating a housing 4202 and a nozzle part 4206 of the injector 42 is formed integrally with the heat insulation member 44.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an intake port structure of an internal combustion engine, and more particularly to an intake port heat insulation structure of a port injection type internal combustion engine.

In recent years, there has been a demand for an internal combustion engine having a high compression ratio with improved thermal efficiency from the viewpoint of improving fuel efficiency.
A high compression ratio internal combustion engine is more likely to knock than a low compression ratio engine, and the ignition timing must be retarded.
As a result, the fuel efficiency improvement effect is reduced, and it is necessary to suppress an increase in the intake air temperature and thus the mixture temperature.
Incidentally, the intake air is sucked into the combustion chamber via the intake passage of the intake manifold and the intake port provided in the cylinder head.
Since the intake manifold and the cylinder head are heated by the heat transmitted from the combustion chamber, it is inevitable that the temperature of the intake air rises due to receiving heat from the intake passage of the intake manifold and the wall surface of the intake port of the cylinder head.
In view of this, an intake pipe mounting structure has been proposed in which the intake manifold is made of a heat-insulating resin material, and the resin insertion portion of the intake manifold is inserted into the intake port (see Patent Document 1).
In this structure, the resin insertion part is inserted to the part in contact with the intake port inside the cylinder head, and a part of the resin insertion part is arranged inside the intake port, so that the wall surface of the cylinder head among the wall surfaces of the intake port The area of the part composed of is reduced to suppress the rise in intake air temperature.

JP 2007-285171 A

On the other hand, from the viewpoint of reducing fuel consumption, it is necessary to efficiently introduce the fuel injected from the injector into the intake port into the combustion chamber. For this reason, the injector is arranged so that the injector nozzle is close to the combustion chamber. It is desirable to do.
However, if the injector is brought close to the combustion chamber, the injector is likely to be exposed to heat from the combustion chamber, and the coil temperature of the actuator that drives the needle valve of the injector rises, which may affect the operation of the injector. Is done.
In view of the above circumstances, the present invention has been made paying attention to the heat insulating effect of the heat insulating member, and is an intake port heat insulating structure for an internal combustion engine that is advantageous in improving fuel efficiency while ensuring a smooth fuel injection operation of the injector. The purpose is to provide.

In order to achieve the above-described object, the invention according to claim 1 includes an injector that is disposed in the cylinder head and supplies fuel to the intake port, and a heat insulation that is incorporated in the cylinder head and forms a part of the wall surface of the intake port. An intake port heat insulating structure for an internal combustion engine comprising a member, wherein the heat insulating member is integrally formed with an injector housing portion for housing a housing of the injector and a nozzle portion, and the injector is disposed on the side where the injector is disposed. The wall surface of the intake port is the wall surface of the cylinder head in a range where the fuel injected from the injection port of the injector by the intake air flowing through the intake port adheres to the heat insulating member at the downstream end of the intake port. A notch to be formed is provided.
According to a second aspect of the present invention, the heat insulating member includes an upstream side wall portion that forms the entire circumference of the wall surface on the upstream side of the intake port from the injection port, and a downstream surface that forms the wall surface on the downstream side of the intake port from the injection port. It is comprised from a side wall part, The said notch is provided in the said downstream side wall part, It is characterized by the above-mentioned.
According to a third aspect of the present invention, the downstream side wall portion constitutes a wall surface of the intake port facing the injection port, and the wall surface is located at a location downstream of the intake port to which fuel injected from the injection port is not attached. It is extended to the wall surface.
According to a fourth aspect of the present invention, the heat insulating member has an inner surface that constitutes a wall surface of the intake port and an outer surface that is fitted into a recess of the cylinder head, and the outer surface is a downstream portion of the intake port. It has the inclined surface where an outer diameter dimension becomes small as it approaches.

According to the first aspect of the present invention, the housing and the nozzle portion of the injector are covered with the heat insulating member, whereby the housing and the nozzle portion are insulated from the heat from the combustion chamber. Therefore, even if the injector nozzle is arranged close to the combustion chamber, the injector is not easily exposed to heat from the combustion chamber, which is advantageous in improving fuel efficiency while ensuring a smooth fuel injection operation of the injector. .
In addition, since the wall surface of the intake port in the range where the fuel injected from the injector nozzle adheres by the intake air flowing through the intake port is formed by the wall surface of the cylinder head, the wall surface of the intake port is The adhering fuel is efficiently vaporized on the wall surface of the high-temperature cylinder head, which is advantageous in improving the combustion efficiency of the fuel.
According to invention of Claim 2, said effect can be achieved with a simple structure.
According to claim 3, in the low-speed rotation region of the internal combustion engine, the wall surface of the intake port, which is the location of the wall surface to which the fuel injected from the injection port of the injector is not attached, is constituted by the downstream side wall portion of the heat insulating member. The transfer of heat from the cylinder head to the intake air is suppressed, which is advantageous in suppressing an increase in intake air temperature. Therefore, it is advantageous for improving the fuel consumption of the internal combustion engine.
According to the fourth aspect of the present invention, when the heat insulating member is fitted into the concave portion of the cylinder head, it is advantageous to prevent the heat insulating member from rattling.

It is sectional drawing which shows the intake port structure of the internal combustion engine which concerns on embodiment. 1A is a sectional view taken along line AA in FIG. 1, FIG. 1B is a sectional view taken along line BB in FIG. 1, and FIG. 1C is a sectional view taken along line CC in FIG. It is a perspective view of the heat insulation member which shows the state in which the injector was accommodated in the injector accommodating part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, the overall configuration of the internal combustion engine will be described.
As shown in FIG. 1, an internal combustion engine (hereinafter referred to as engine) 10 includes a cylinder block 14 in which a cylinder 12 is formed, a cylinder head 16 disposed on the cylinder block 14, and a piston disposed in the cylinder 12. 18.
An intake pipe 20 (intake manifold) and an exhaust pipe 22 (exhaust manifold) are connected to both sides of the cylinder head 16.
The combustion chamber 24 is constituted by the inner surface of the cylinder 12, the lower surface of the cylinder head 16, and the top surface of the piston 18, and the cylinder head 16 is provided with an ignition plug 26 so as to be positioned in the combustion chamber 24.
The piston 18 is connected to a crankshaft (not shown) via a connecting rod 28. In the figure, reference numerals 1802 and 1804 denote pressure rings, and reference numeral 1806 denotes an oil ring.

The cylinder head 16 is provided with an intake port 30 for supplying intake air to the combustion chamber 24 and an exhaust port 32 for discharging exhaust gas in the combustion chamber 24.
An intake pipe 20 is connected to the intake port 30, and an exhaust pipe 22 is connected to the exhaust port 32.
The intake passage 2002 includes the intake pipe 20 and the intake port 30, and the exhaust passage 2202 includes the exhaust port 32 and the exhaust pipe 22.
An intake valve 34 is provided at the intake port 30 and an exhaust valve 36 is provided at the exhaust port 32. The intake valve 34 and the exhaust valve 36 are urged by valve springs 38 and 40 in the closing direction. The intake valve 34 and the exhaust valve 36 are driven by an intake / exhaust cam (not shown) to open and close the intake port 30 and the exhaust port 32.
In the figure, reference numeral 37 denotes a valve seat.

In the present embodiment, engine 10 is a port injection engine that injects (sprays) fuel from injector 42 into intake port 30.
In the port injection type engine, the intake air sucked into the intake port 30 from the intake passage 2002 of the intake pipe 20 and the fuel injected from the injection port 4208 of the injector 42 are mixed in the intake port 30 to become an air-fuel mixture, and combustion It is supplied to the chamber 24.
When the crankshaft rotates, the intake valve 34 and the exhaust valve 36 are opened and closed via the intake cam and the exhaust cam, and the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke are executed. The fuel is injected into the intake port 30 from the nozzle 4208.
The injector 42 is accommodated and held in the heat insulating member 44 as will be described later.
The injector 42 injects fuel supplied via a fuel rail 48 from a pump (not shown).
The injector 42 includes a housing 4202, a port portion 4204, a nozzle portion 4206, and a needle valve (not shown) and an actuator (not shown) incorporated in the nozzle portion 4206.
The port portion 4204 is a portion provided at the base portion of the housing 4202 and connected to the fuel rail 48.
The nozzle portion 4206 is connected to the opposite side of the port portion 4204 of the housing 4202 and directs the injection port 4208 into the intake port 30.
The needle valve opens and closes the nozzle 4208.
The actuator has a coil and opens and closes the nozzle 4208 by driving the needle valve with a drive current flowing through the coil.

As shown in FIGS. 1 to 3, the intake port 30 is constituted by a heat insulating member 44 with a part of the wall surface attached to the cylinder head 16.
That is, a recess 46 is provided that opens on the end surface of the cylinder head 16 where the upstream end of the intake port 30 is located.
The heat insulating member 44 is fitted into the recess 46, and the mounting flange 2010 of the intake pipe 20 is attached to the cylinder head 16, so that it is pressed against the recess 46 by the mounting flange 2010 and incorporated into the cylinder head 16.
The heat insulating member 44 has an outer surface 4402 that contacts the wall surface 4602 of the recess 46 and an inner surface 4404 that forms part of the wall surface of the intake port 30.
As shown in FIG. 3, the outer surface 4402 includes an inclined surface 4402 </ b> A that decreases in outer diameter as it approaches the downstream portion of the intake port 30, and the heat insulating member 44 is fitted into the recess 46 of the intake port 30. Sometimes, it is advantageous to fit the heat insulating member 44 without rattling.

As shown in FIGS. 1 and 2, the heat insulating member 44 includes a substantially cylindrical upstream side wall portion 44 </ b> A located upstream of the injection port 4208 and an end portion of the upstream side wall portion 44 </ b> A positioned downstream of the injection port 4208. And a semi-cylindrical downstream side wall portion 44B extending in the direction in which the intake air flows.
The intake air in a range where the fuel injected from the injection port 4208 of the injector 42 by the intake air flowing through the intake port 30 adheres to the downstream side wall portion 44B on the side where the injector 42 is disposed at the downstream end of the intake port 30. A notch 50 for forming the wall surface of the port 30 with the wall surface 3006 of the cylinder head 16 is provided.
Further, the downstream side wall 44B constitutes a wall surface 3004 of the intake port 30 on the side facing the injection port 4208, and this wall surface 3004 extends to a location downstream of the intake port 30 to which fuel injected from the injection port 4208 is not attached. ing. Therefore, the wall surface 3008 in the range where the fuel injected from the nozzle 4208 is attached at the location of the wall of the intake port 30 on the side facing the nozzle 4208 is constituted by the cylinder head 16.

In addition, an injector housing portion 52 that houses the housing 4202 and the nozzle portion 4206 of the injector 42 is formed integrally with the heat insulating member 44.
The injector housing part 52 includes a first hole part 5202 and a second hole part 5204.
The first hole 5202 is a place for housing the housing 4202, and the second hole 5204 is a place for housing the nozzle part 4206.
The second hole 5204 is formed so as to be coaxial with the first hole 5202 and have a smaller inner diameter than the first hole 5202.
In the injector 42, the housing 4202 is accommodated in the first hole portion 5202, and the nozzle portion 4206 is accommodated in the second hole portion 5204 via an O-ring 4210 that is a seal member, and the nozzle 4208 is exposed to the intake port 30. It is arranged in the state.
The injector 42 has a port portion 4204 connected to the fuel rail 48, and the fuel rail 48 has a protruding piece 4802 protruding from the fuel rail 48 and a screw 54 attached to a mounting portion 1602 protruding from the cylinder head 16. Has been attached via.
As a result, the injector 42 is pressed against the injector accommodating portion 52 by the axial force of the screw 54 that attaches the fuel rail 48 to the cylinder head 16, and the state where the injector 42 is accommodated in the injector accommodating portion 52 is maintained.
In addition, the attachment location of the protrusion piece 4802 is not limited to the cylinder head 16, For example, the intake pipe 20 and the heat insulation member 44 may be sufficient.

The heat insulating member 44 may be made of a hollow or solid synthetic resin material.
Alternatively, the heat insulating member 44 may be constituted by a hollow member and a heat insulating material inserted into the hollow member, and in this case, it is advantageous in securing optimum heat insulating performance.
Further, the upstream portion 44A and the downstream portion 44B of the heat insulating member 44 may be configured separately. In this case, the heat insulation performance can be changed by changing the kind of heat insulating material used for the upstream portion 44A and the downstream portion 44B.
For example, when the cooling water passage (high temperature) is disposed in the cylinder head 16 portion where the upstream portion 44A is disposed and the cylinder head 16 portion where the downstream portion 44B is disposed is at a lower temperature, the downstream portion 44B. The heat insulating material constituting the heat insulating member 44 can be selected or the density of the heat insulating material can be set so as to improve the heat insulating performance of the upstream portion 44A.
Therefore, it is advantageous in ensuring optimum heat insulation performance corresponding to the temperature distribution of the cylinder head 16.

According to the present embodiment, since the injector 42 is accommodated and disposed in the injector accommodating portion 52 provided in the heat insulating member 44, the housing 4202 and the nozzle portion 4206 are covered with the heat insulating member 44 so that the housing 4202 is covered. In addition, the nozzle portion 4206 is insulated from the heat from the combustion chamber 24.
Therefore, even if the nozzle hole 4208 of the injector 42 is disposed close to the combustion chamber 24, the injector 42 is not easily exposed to heat from the combustion chamber 24, and the coil temperature of the actuator of the injector 42 rises, so that the operation of the injector 42 is performed. It can suppress being influenced.
Therefore, it is advantageous for improving fuel efficiency while ensuring a smooth fuel injection operation of the injector 42.

Further, since the notch 50 is provided in the downstream side wall portion 44B, when the intake speed flowing through the intake port 30 increases in the high speed rotation region of the engine 10, most of the fuel injected from the injection port 4208 is located at the injection port 4208. It adheres to the location of the wall surface 3006 of the cylinder head 16 that extends along the direction in which the intake port 30 extends.
Therefore, in the high speed rotation region of the engine 10, the fuel adhering to the wall surface 3006 of the intake port 30 is efficiently vaporized by the wall surface 3006 of the high-temperature cylinder head 16, which is advantageous for improving the combustion efficiency of the fuel.
Further, the upstream side wall portion 44 </ b> A suppresses the transfer of heat from the cylinder head 16 to the intake air, which is advantageous for suppressing the temperature rise of the intake air, and is advantageous for improving the fuel consumption of the engine 10.
Therefore, the combustion efficiency can be improved while suppressing the temperature rise of the intake air, which is advantageous in improving the fuel consumption of the engine 10.

Further, in the present embodiment, the downstream side wall 44B constitutes a wall surface 3004 of the intake port 30 on the side facing the injection port 4208, and this wall surface 3004 is a downstream location of the intake port 30 to which fuel injected from the injection port 4208 is not attached. The range of the wall surface 3008 that extends to the surface and to which the fuel is attached is constituted by the cylinder head 16.
Therefore, in the low speed rotation region of the engine 10, most of the fuel injected from the nozzle 4208 adheres to the wall surface 3008 of the cylinder head 16 of the intake port 30 near the combustion chamber 24 and the intake valve 34 on the side facing the nozzle 4208. To do.
Therefore, in the low speed rotation region of the engine 10, the fuel adhering to the wall surface 3008 of the intake port 30 is efficiently vaporized, which is advantageous for improving the combustion efficiency of the fuel.
Further, the downstream side wall 44B suppresses the transfer of heat from the cylinder head 16 to the intake air, which is more advantageous in suppressing the temperature rise of the intake air.
Therefore, in the low-speed rotation region of the engine 10, the combustion efficiency can be further improved while further suppressing the rise in intake air temperature, which is further advantageous in improving the fuel consumption of the engine 10.

10 Engine (Internal combustion engine)
16 Cylinder head 20 Intake pipe 30 Intake port 3002 Port wall upper surface 3004 Port wall lower surface 3006 Wall surface 3008 Wall surface 42 Injector 4202 Housing 4206 Nozzle portion 4208 Injection hole 44 Heat insulating member 4402 Outer surface 4402A Inclined surface 4404 Inner surface 44A Upstream side wall portion 44B Downstream side wall portion 46 Recessed portion 50 Notch 52 Injector housing

Claims (4)

An injector disposed in the cylinder head for supplying fuel to the intake port;
A heat insulating member incorporated in the cylinder head and forming a part of the wall surface of the intake port;
An intake port heat insulation structure for an internal combustion engine comprising:
The heat insulating member is integrally formed with an injector housing portion for housing the injector housing and the nozzle portion,
The intake port in a range where the fuel injected from the injection port of the injector by the intake air flowing through the intake port adheres to the location of the heat insulating member on the side where the injector is disposed at the downstream end of the intake port A notch for forming the wall surface of the cylinder head with the wall surface of the cylinder head,
An intake port heat insulation structure for an internal combustion engine. The heat insulating member is composed of an upstream side wall portion that forms the entire circumference of the wall surface on the upstream side of the intake port from the injection port, and a downstream side wall portion that forms a wall surface on the downstream side of the intake port from the injection port,
The notch is provided in the downstream side wall,
The intake port heat insulation structure for an internal combustion engine according to claim 1. The downstream side wall portion constitutes a wall surface of the intake port on the side facing the injection port, and the wall surface extends to a wall surface at a location downstream of the intake port to which fuel injected from the injection port is not attached.
The intake port heat insulation structure for an internal combustion engine according to claim 2. The heat insulating member has an inner surface that constitutes a wall surface of the intake port, and an outer surface that is fitted into the recess of the cylinder head,
The outer surface has an inclined surface that decreases in outer diameter as it approaches the downstream portion of the intake port.
The intake port heat insulation structure for an internal combustion engine according to claim 2 or 3,

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