JP2017020474A - engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an in-cylinder combustion state in an engine.SOLUTION: An engine includes an intake valve 10 for opening and closing an opening 2 on a cylinder 23 side of an intake port 1. The engine further includes a gas injection port 6 for injecting gas toward a direction passing through a position near an axis of the cylinder 23 of a gap between the opened intake valve 10 and the opening 2 and a direction abutting with a cylinder liner 24 of the cylinder 23 in the intake port 1. Furthermore, a fuel injection port 8 is provided for injecting fuel into the intake port 1 in which the flow of the gas is formed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an engine equipped with an EGR system that introduces part of exhaust gas into an intake system.

  Conventionally, an EGR (Exhaust Gas Recirculation) system that improves fuel efficiency and environmental performance by recirculating exhaust gas of an engine mounted on a vehicle from an exhaust system to an intake system is known. That is, the exhaust passage and the intake passage are connected by the EGR passage, and a part of the exhaust gas is introduced into the cylinder again as EGR gas. In recent years, an EGR system in which the outlet of the EGR passage is set as an intake port has been developed. By supplying EGR gas to the intake air flow just before being taken into the cylinder, the fresh air, fuel mixture, and EGR gas are easily introduced into the cylinder while being separated into layers, and the combustion state in the cylinder Can be stabilized (see Patent Document 1).

JP 2009-121366 JP

  However, since pressure pulsation occurs due to opening and closing of the intake valve in the intake port, it is difficult to sufficiently separate EGR gas and fuel depending on the timing of fuel injection and the timing of introduction of EGR gas. . For example, when fuel injection is performed in the exhaust stroke in which the intake valve is closed, the vaporized fuel stays in the intake port. After that, when the intake valve is opened during the intake stroke, the pressure in the intake port decreases and fresh air and EGR gas flow into the intake port.

  At this time, the vaporized fuel staying in the intake port and the EGR gas are mixed and introduced into the cylinder. As a result, it becomes difficult to form a stratified state of the air-fuel mixture in which fuel and fresh air are mixed and the EGR gas, and the combustion state in the cylinder may become unstable. On the other hand, even if fuel is injected during the intake stroke, fresh air flows into the intake port later than the EGR gas, so it is difficult to avoid mixing of fuel spray and EGR gas.

  One of the objects of the present case has been devised in view of the above-described problems, and is to provide an engine that improves the combustion state in a cylinder. It should be noted that the present invention is not limited to this purpose, and is an operational effect that is derived from each configuration shown in “Mode for Carrying Out the Invention” to be described later. Can be positioned as a purpose.

(1) The engine disclosed herein includes an intake valve that opens and closes an opening on the cylinder side of the intake port. Further, in the intake port, gas flows in a direction passing through a position near the cylinder axis of the cylinder in a gap between the opened intake valve and the opening, and in a direction hitting the cylinder liner of the cylinder. A gas injection port for injection is provided. Furthermore, a fuel injection port for injecting fuel into the intake port where the gas flow is formed is provided.
In addition, it is preferable that the gas injection port injects the gas in a direction along a wall surface in the intake port.

(2) It is preferable that the gas injection port is disposed on a wall surface above the center line of the intake port.
In addition, it is preferable that the said gas injection port is arrange | positioned at the wall surface of the outer peripheral side (turning outer side) in the bending location in the said intake port.
(3) It is preferable that the gas injection port injects the gas between a stem base end portion of the intake valve and the cylindrical shaft.

(4) It is preferable that the fuel injection port is disposed on the wall surface above the center line of the intake port and on the upstream side of the gas injection port.
The term “upstream side” as used herein means that it is located on the far side from the opening with respect to the center line of the intake port. For example, the position of a vertical leg extending from the gas injection port to the center line is compared with the position of a vertical foot extending from the fuel injection port to the center line, and the former is more from the opening than the latter. When the fuel injection port is on the near side, the fuel injection port is disposed upstream of the gas injection port.

(5) It is preferable that the fuel injection port is disposed on a wall surface below the center line of the intake port.
(6) It is preferable that the intake port has a siamese shape in which one passage is branched toward the plurality of openings. In this case, it is preferable that the fuel injection port injects the fuel toward a branch point of the intake port.

  (7) It is preferable that the gas injected from the gas injection port is a part of the exhaust of the engine. That is, the gas injection port is preferably an exhaust gas recirculation port that injects a part of the exhaust gas into the intake port. The exhaust gas recirculation port may be an end opening of an exhaust gas recirculation passage that introduces a portion of the exhaust gas into the intake port without pressurizing. Alternatively, it may be an end opening of an exhaust gas recirculation passage that pressurizes a part of the exhaust gas and introduces it into the intake port.

  (8) The fuel injection port stops fuel injection in the intake stroke until at least the intake valve is opened, and starts the fuel injection after the intake valve into which the gas flows into the cylinder is opened. It is preferable. In this case, it is preferable to provide a control device for controlling the fuel injection state from the fuel injection port.

  According to the disclosed engine, it is possible to improve the combustion state while suppressing fuel adhesion to the cylinder inner wall surface.

It is typical sectional drawing which shows the structure of the engine as embodiment. It is a cylinder top view of an engine. It is a perspective view which shows the distribution | circulation state of an exhaust flow typically. (A) is a valve lift, (B) is a graph which shows valve opening acceleration. It is typical sectional drawing of an engine (intake stroke initial stage). It is typical sectional drawing of an engine (at the time of fuel injection). It is typical sectional drawing of an engine (intake stroke middle period). It is typical sectional drawing which shows the structure of the engine as a modification.

  An engine as an embodiment will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit thereof. Further, they can be selected as necessary, or can be appropriately combined. In the following description, it is assumed that the vertical direction of each part is determined based on a state in which the engine is disposed so that the central axis of the cylinder is vertical (a state where the intake port and the exhaust port are located above).

[1. Constitution]
[1-1. engine]
An engine 20 of the present embodiment is shown in FIG. The engine 20 is a gasoline engine having an EGR system (exhaust gas recirculation system) that circulates a part of exhaust gas into the intake port 1 of the cylinder head 21. The top surface shape of the cylinder 23 of the engine 20 is a pent roof type (gable roof type) in which an inclined surface to which the intake port 1 is connected and an inclined surface to which the exhaust port 3 is connected are combined in a triangular roof shape. On the top surface, an intake valve 10 is provided in the opening 2 connected to the intake port 1, and an exhaust valve 15 is provided in the opening 4 connected to the exhaust port 3. Two each of these openings 2, 4, intake valve 10, and exhaust valve 15 are provided in one cylinder 23. As shown in FIG. 2, the intake port 1 has a siamese shape in which one passage is branched toward the two openings 2. Similarly, the exhaust port 3 has a siamese shape in which the passages connected to the two openings 4 are joined together. One opening 2 and one intake valve 10 may be provided in each cylinder 23, and the intake port 1 and the exhaust port 3 do not have to have a Siamese shape.

  The intake port 1 is connected to an exhaust return passage 5 that is one of the EGR passages, and is provided with an injector 7. Here, the end opening of the exhaust return passage 5 opened toward the intake port 1 is referred to as an exhaust recirculation port 6. Further, the injection hole of the injector 7 is called a fuel injection port 8. The upstream side of the exhaust return passage 5 is connected to the exhaust passage of the engine 20. The upstream side of the injector 7 is connected to a fuel supply pipe.

[1-2. Exhaust recirculation port]
The exhaust gas recirculation port 6 (gas injection port) is for injecting gas into the intake port 1. For example, exhaust gas that has passed through the exhaust return passage 5 is injected as an exhaust flow toward the opening 2 in the intake port 1. It has a function to do. The exhaust gas recirculation port 6 of the present embodiment is an end opening of an EGR passage that introduces a part of the exhaust gas into the intake port 1 without pressurizing. When an EGR system that pressurizes a part of the exhaust and introduces it into the intake port 1 is provided, the end opening of the EGR passage through which the pressurized exhaust flows functions as the exhaust recirculation port 6. You may let them. Further, a gas other than exhaust gas may be injected into the intake port 1.

  The shape of the exhaust flow injected from the exhaust gas recirculation port 6 is generally a rod shape along the path from the exhaust gas recirculation port 6 to the opening 2. The flow rate of the exhaust flow injected from the exhaust recirculation port 6 varies according to the exhaust pressure and the intake pressure (internal pressure of the intake port 1). Further, when a flow rate control valve (EGR valve) or a pressurization / decompression device is provided in the exhaust return passage 5, the exhaust return passage 5 varies depending on the opening degree of the flow control valve and the pressure in the exhaust return passage 5.

  The position of the exhaust gas recirculation port 6 is set on the inner wall surface above the center line of the intake port 1 in the longitudinal section of the engine 20. That is, the exhaust gas recirculation port 6 is provided on the outer peripheral wall surface at the bent portion of the intake port 1. In the example shown in FIG. 1, the exhaust gas recirculation port 6 is provided in the vicinity of the wall surface of the intake port 1, but the exhaust return passage 5 is extended to the inside of the intake port 1 and is located slightly away from the wall surface of the intake port 1. An exhaust gas recirculation port 6 may be arranged. As shown in FIG. 2, one exhaust recirculation port 6 is provided for each of the two openings 2 in each cylinder 23.

  The injection direction of the exhaust flow is at least a direction along the inner wall surface of the intake port 1. Preferably, as shown in FIG. 1, the exhaust flow is injected along the outer peripheral wall surface of the bent portion of the intake port 1. As a result, while the exhaust flow is being injected, the surface on the outside of the turn in the intake port 1 is covered with the exhaust flow in a curtain shape, and adhesion of fuel injected from the injector 7 is suppressed.

  As shown in FIGS. 1 and 3, the injection direction of the exhaust flow injected from the exhaust recirculation port 6 (injection direction of the exhaust flow in a side view of the engine 20) is the intake valve 10 opened in the intake port 1. And a direction passing through a position E near the cylinder axis C (the center axis of the cylinder 23) and a direction abutting on the cylinder liner 24 of the cylinder 23. That is, the injection direction of the exhaust flow is at least non-parallel to the cylinder axis C. As shown in FIG. 3, the position E through which the exhaust flow passes is located on a straight line from the base end portion of the stem 11 toward the cylinder axis C of the cylinder 23.

  Further, the injection direction of the exhaust flow in a top view of the engine 20 is set to a direction passing between the base end portion of the stem 11 of the intake valve 10 and the cylinder shaft C as shown in FIG. Here, when the injection direction from one exhaust gas recirculation port 6 and the injection direction from the other exhaust gas recirculation port 6 are viewed in a top view, the intersection of each extension line is located in the vicinity of the surface of the cylinder liner 24. . That is, the exhaust flow injected from one exhaust recirculation port 6 collides with the exhaust flow injected from the other exhaust recirculation port 6 in the vicinity of the cylinder liner 24 and diffuses downward along the inner cylinder surface. Circulate. Accordingly, the entire surface of the cylinder liner 24 is covered with the exhaust flow, and fuel adhesion to the wall surface in the cylinder 23 is suppressed.

[1-3. Fuel injection port]
The fuel injection port 8 has a function of injecting fuel into the intake port 1 during the intake stroke of the engine 20. The fuel is injected into the intake port 1 where the exhaust flow is formed. The fuel injection amount injected from the fuel injection port 8 varies depending on the pressure (fuel pressure) of the fuel supplied to the fuel injection port 8 and the valve opening time of the fuel injection port 8.
The position of the fuel injection port 8 is set on the inner wall surface on the upstream side of the exhaust gas recirculation port 6 and on the upper side of the intake port 1 in the longitudinal section. The exhaust flow injected from the exhaust recirculation port 6 circulates along the inner wall surface of the intake port 1 and becomes a laminar flow covering the surface. On the other hand, the fuel is injected from the upstream side of the inner wall surface whose surface is covered by the exhaust flow. Thereby, adhesion of fuel to the inner wall surface of the intake port 1 is suppressed.

  The upstream side here means that the distance to the opening 2 is long with the center line of the intake port 1 as a reference. For example, as shown in FIG. 1, a perpendicular line is drawn from the exhaust gas recirculation port 6 to the center line of the intake port 1, and the leg of the perpendicular line is a point A. On the other hand, a perpendicular is drawn from the fuel injection port 8 to the center line of the intake port 1, and the leg of the perpendicular is designated as point B. The point B is arranged at a position farther from the opening 2 than the point A. Further, as shown in FIG. 2, the position of the fuel injection port 8 in the top view of the engine 20 is upstream of the siamese portion 27 where the intake port 1 branches toward the two openings 2. 1 is arranged at approximately the center.

  As shown in FIG. 1, the fuel injection direction is a direction along the injection direction of the exhaust flow injected from the exhaust gas recirculation port 6. Here, the “direction along the injection direction of the exhaust flow” is a fuel injection direction in which the angle formed with the flow direction of the exhaust flow is within a range of about −45 ° to 45 °. The “direction along the injection direction of the exhaust flow” includes a direction parallel to the flow direction of the exhaust flow. Further, the fuel injection direction in the top view of the engine 20 is set to a direction toward the siamese portion 27 that is an intermediate position between the two openings 2 as shown in FIG. Thereby, fuel spray is supplied to each of the exhaust flow drawn into one opening 2 and the exhaust flow drawn into the other opening 2. Further, the fuel adhering to the siamese portion 27 is vaporized in the vicinity thereof and is introduced together with the exhaust flow from each of the two openings 2.

[1-4. Control device]
The control device 9 is an electronic control device that controls at least the fuel injection system of the engine 20, and is an electronic device in which a processor such as a CPU and MPU, a ROM, a RAM, a nonvolatile memory, and the like are integrated. The processor is an arithmetic processing unit that includes a control circuit, an arithmetic circuit, a cache memory, and the like. The ROM, RAM, and nonvolatile memory are memory devices that store programs and working data. The contents of control by the control device 9 are recorded in ROM, RAM, and nonvolatile memory as application programs. When the program is executed, the contents of the program are expanded in the memory space in the RAM and executed by the processor.

Connected to the control device 9 is a cam angle sensor 31 that detects the rotation angle (cam rotation angle) of the cam shaft that drives the intake cam 25 and the exhaust cam 26 and a crank angle sensor 32 that detects the crank angle of the engine 20. Is done. The control device 9 controls the fuel injection amount, injection timing, and fuel pressure of the injector 7 based on the cam rotation angle and the crank angle.
The timing of fuel injection is set at least within the intake stroke of the engine 20 and while the intake valve 10 is open. Preferably, control is performed based on the opening acceleration of the intake valve 10 in the intake stroke. Here, fuel injection is performed within the intake stroke (after exhaust top dead center) and at least after the intake valve 10 is opened. That is, fuel injection is performed in a state where the exhaust flow injected from the exhaust recirculation port 6 is introduced into the cylinder 23 through the gap between the opened intake valve 10 and the intake port 1. Further, in the present embodiment, within the intake stroke of the engine 20, at least after a predetermined time has elapsed since the intake valve 10 opened [within the section θ ₂ to θ ₅ in FIG. 4A]. Fuel injection is started. The predetermined time here is set based on the opening acceleration of the intake valve 10. For example, the time until the opening acceleration of the intake valve 10 changes from positive to negative during the intake stroke is set as the predetermined time.

Each of the crank angles θ ₁ , θ ₃ , and θ ₅ in FIG. 4A corresponds to the valve opening time, the maximum opening time, and the valve closing time of the intake valve 10. The crank angles θ ₂ and θ ₄ are crank angles that give inflection points to the valve lift graph. Valve opening acceleration, as shown in FIG. _{4 (B), θ 1 ~θ} 2 section is positive, theta ₂ through? ₄ segment is negative, theta ₄ through? ₅ section becomes positive again. The control device 9 starts fuel injection at least after the exhaust top dead center and after the time when the crank angle θ is θ ₁ . Thereby, mixing of the fuel and the exhaust flow in the intake port 1 is suppressed. In order to more reliably suppress the mixing of the fuel and the exhaust flow, it is preferable to move the fuel injection start timing in a more retarded direction. The control device 9 of the present embodiment stops fuel injection from the fuel injection port 8 until the opening acceleration changes from positive to negative during the intake stroke (until a predetermined time elapses). As a result, fuel injection is performed in a state where the exhaust flow in the intake port 1 is being introduced into the cylinder 23, and therefore, mixing of fuel and exhaust flow in the intake port 1 may be suppressed. Will rise significantly.

Although the timing at which the fuel injection ends may vary depending on the total fuel injection amount and the fuel pressure, it is preferable to end the fuel injection within the intake stroke. Therefore, it is preferable that the fuel pressure is controlled to increase as the engine speed or the engine load increases. This makes it easy to inject a desired amount of fuel into the intake stroke. Note that the timing at which the intake stroke is started and the timing at which the intake stroke is started can be arbitrarily set, and may be completely matched with the θ _{1 to} θ ₅ sections or may not be matched. By using a known variable valve timing mechanism, the intake stroke can be shifted from the θ ₁ to θ ₅ interval in the advance angle direction or the retard angle direction.

[2. Action]
When the intake valve 10 is opened, the internal pressure of the intake port 1 decreases to a negative pressure, and the exhaust is injected from the exhaust recirculation port 6 through the exhaust return passage 5. At this time, since the fuel injection is stopped, the exhaust flow mainly flows into the cylinder 23 from the intake port 1. The exhaust flow is introduced into the cylinder 23 through a position near the cylinder axis C in the gap between the umbrella portion 12 and the opening 2 of the intake valve 10 as indicated by a black arrow in FIG. . Further, in the cylinder 23, the exhaust flow goes straight toward the cylinder liner 24 of the cylinder block 22. In the vicinity of the cylinder liner 24, the exhaust flow flowing in from one opening 2 collides with the exhaust flow flowing in from the other opening 2, and circulates while diffusing downward along the inner cylinder surface. As a result, the exhaust gas descends along the surface of the cylinder liner 24, and then a swirl flow is formed that swirls along the piston top surface toward the cylinder axis C of the cylinder 23.

  When the opening acceleration of the intake valve 10 changes from positive to negative during the intake stroke of the engine 20, fuel is injected from the fuel injection port 8 as shown in FIG. The fuel is introduced into the cylinder 23 together with the exhaust flow while flowing in the external airflow (indicated by the white arrow in FIG. 6) sucked into the intake port 1 from the intake manifold side. At this time, the wall surface above the center line of the intake port 1 (surface on the outside of the turning) is covered with the curtain by the exhaust flow, so that the fuel is less likely to adhere to the inner wall surface of the intake port 1. Further, since the fuel injection direction is the direction along the exhaust flow, the fuel is less likely to be mixed into the exhaust flow, and a part of the fuel spray rides on the surface layer of the exhaust flow and is introduced into the cylinder 23. . Further, the other part of the fuel spray is introduced into the cylinder 23 through the gap between the intake valve 10 and the opening 2.

  As shown in FIG. 7, the fuel in a state where it is wrapped in the surface layer of the exhaust flow is transported along the swirl flow together with the exhaust flow in the cylinder 23. Thereby, fuel adhesion to the cylinder liner 24 in the cylinder 23 is suppressed. Further, the fuel vaporized in the intake port 1 or in the cylinder 23 removes latent heat of vaporization from the surrounding air and the cylinder liner 24 to lower the in-cylinder temperature. Thereby, filling efficiency and volumetric efficiency are increased, and the knocking resistance of the engine 20 is improved.

[3. effect]
(1) In the engine 20, as shown in FIGS. 1 and 3, the exhaust flow is injected toward the direction passing through the position E near the cylinder axis C in the gap between the intake valve 10 and the opening 2. The The exhaust flow hits the cylinder liner 24 in the cylinder 23 and flows downward along the inner cylinder surface of the cylinder 23. As a result, the surface of the cylinder liner 24 can be covered (covered) with the exhaust flow, and fuel adhesion to the wall surface in the cylinder 23 can be suppressed. Therefore, the combustion state in the cylinder 23 can be improved.

  (2) In the engine 20 described above, the exhaust gas recirculation port 6 is provided on the wall surface above the center line of the intake port 1. That is, the exhaust gas recirculation port 6 is provided on the outer peripheral wall surface at the bent portion of the intake port 1. As a result, while the exhaust flow is being injected, the outer surface of the intake port 1 can be covered (covered) in a curtain shape with the exhaust flow. Therefore, the transportability of the fuel into the cylinder 23 can be improved.

  (3) The gap between the opened intake valve 10 and the opening 2 forms an annular shape along the outer periphery of the umbrella portion 12 of the intake valve 10. On the other hand, the position E shown in FIG. 3 is arranged on a straight line from the base end portion of the stem 11 toward the cylinder axis C in the annular gap. Thereby, compared with the case where the exhaust flow is injected toward the base end portion of the stem 11, the straightness of the exhaust flow in the cylinder 23 can be improved. That is, it is possible to easily form an exhaust flow toward the cylinder liner 24 in the cylinder 23. Therefore, fuel adhesion to the cylinder liner 24 can be efficiently suppressed, and the combustion state can be further improved.

  (4) In the engine 20 described above, the fuel injection port 8 is disposed upstream of the exhaust gas recirculation port 6, that is, the exhaust gas recirculation port 6 is disposed downstream of the fuel injection port 8. Thereby, fuel can be injected toward the inner wall surface of the intake port 1 covered with the exhaust flow. Therefore, the amount of fuel attached to the port can be reduced. Further, since the direct injection rate of the fuel increases, the intake air cooling effect in the cylinder 23 can be enhanced.

  (5) In the engine 20, as shown in FIG. 2, fuel is injected toward the siamese portion 27 of the intake port 1. Thereby, a part of the fuel can be attached to the vicinity of the siamese portion 27 and vaporized. Therefore, the transportability of the fuel into the cylinder 23 can be improved. Further, the vaporized fuel vapor and the fuel spray are introduced into the cylinder 23 along the injection direction of the exhaust flow injected from the exhaust gas recirculation port 6. In this way, a part of the fuel can be easily put on the surface layer of the exhaust flow (can be easily put), and mixing of the fuel and the exhaust flow can be efficiently suppressed. Therefore, the combustion state in the cylinder 23 can be further improved.

  (6) In the engine 20 described above, even during the intake stroke, fuel injection stops until the intake valve 10 is opened. Therefore, fuel adheres to the intake port 1 and to the rear surface 13 of the umbrella portion of the intake valve 10. Can be suppressed. Further, since fuel injection is started after the intake valve 10 is opened, fuel can be conveyed into the cylinder 23 along the flow of the exhaust flow injected from the exhaust recirculation port 6. Thereby, it becomes difficult for fuel to adhere to the cylinder liner 24 in the cylinder 23, and the combustion state in the cylinder 23 can be improved.

(7) In the engine 20 described above, fuel injection stops until a predetermined time elapses after the intake valve 10 is opened. Therefore, a rod-like exhaust flow is introduced into the cylinder 23 ahead of the fuel. can do. Therefore, mixing of the fuel and the exhaust flow can be suppressed (or avoided), and the combustion state in the cylinder 23 can be further improved.
Furthermore, by injecting fuel into the intake stroke after a predetermined time has elapsed, the fuel can be mixed with fresh air and introduced into the cylinder 23 on the surface layer of the exhaust flow. Thereby, the combustion state in the cylinder 23 can be further improved.

  (8) In the engine 20 described above, the fuel injection start time is controlled based on the opening acceleration of the intake valve 10. Thus, the fuel can be injected in consideration of the timing of the exhaust flow drawn from the intake port 1 into the cylinder 23, and the mixed state of the fuel and fresh air can be optimized in the intake port 1. it can. Thereby, the combustion state in the cylinder 23 can be improved.

  (9) In the engine 20, the fuel injection is stopped until the opening acceleration changes from positive to negative during the intake stroke. Thereby, it is possible to accurately grasp the timing at which the air drawing action by the umbrella portion 12 of the intake valve 10 is being relaxed. That is, the exhaust flow in the intake port 1 immediately after the valve opening is drawn into the cylinder 23, and the fuel can be injected after the fresh air is drawn to the vicinity of the fuel injection port 8, and the mixing of the exhaust flow and the fuel In addition, the mixing of fresh air and fuel can be promoted. Therefore, the combustion state in the cylinder 23 can be improved.

  (10) In the engine 20 described above, the fuel pressure is increased as the engine speed or the engine load is higher. As a result, it becomes easy to inject a desired amount of fuel into the intake stroke, the output of the engine 20 can be secured, and the combustion state in the cylinder 23 can be improved. In addition to this, as the engine speed or engine load is higher, the fuel injection start effect can be enhanced by delaying the fuel injection start timing.

[4. Modified example]
The engine 20 shown in FIG. 8 changes the position of the fuel injection port 8 in the above-described embodiment, and faces the exhaust gas recirculation port 6 across the center line of the intake port 1 (ie, from the center line of the intake port 1). Is also arranged on the lower wall surface. The position of the fuel injection port 8 is set upstream of the exhaust gas recirculation port 6 and on the inner wall surface below the intake port 1 in the longitudinal section. On the other hand, the fuel injection direction is a direction along the injection direction of the exhaust flow injected from the exhaust gas recirculation port 6 as in the above-described embodiment. Thus, by arranging the exhaust gas recirculation port 6 on the wall surface opposite to the fuel injection port 8, fuel can be injected toward the wall surface of the intake port 1 covered in a curtain shape by the exhaust flow. As a result, the amount of fuel adhering to the port and the amount adhering to the cylinder liner 24 can be reduced, the transportability of the fuel into the cylinder 23 can be improved, and the combustion state in the cylinder 23 can be improved. it can.

  Further, in the above-described embodiment, the injector 7 that injects the fuel toward the siamese portion 27 is illustrated, but the fuel injection direction in the top view of the engine 20 is not limited to this. For example, the fuel may be injected into each of the two openings 2 in two directions toward substantially the center of the opening 2. As a result, fuel spray can be supplied to each of the exhaust flow drawn into one opening 2 and the exhaust flow drawn into the other opening 2, further improving the transportability of fuel into the cylinder 23. Can be increased.

  The structure of the engine 20 described in the above embodiment is not limited to a multi-port gasoline engine, but can be applied to a single-port gasoline engine or a diesel engine. As long as the internal combustion engine has at least the exhaust gas recirculation port 6 and the fuel injection port 8 in the intake port 1, it is possible to apply the same structure as the above-described embodiment, and the same effect as the above-described embodiment. Can be earned.

1 Intake Port 2 Opening 5 Exhaust Return Passage 6 Exhaust Recirculation Port (Gas Injection Port)
7 Injector 8 Fuel Injection Port 9 Control Device 10 Intake Valve 23 Cylinder 24 Cylinder Liner

Claims (8)

An intake valve that opens and closes the cylinder side opening of the intake port;
In the intake port, gas is injected in a direction passing through a position near the cylinder axis of the cylinder in a gap between the opened intake valve and the opening, and in a direction of abutting on the cylinder liner of the cylinder. A gas injection port;
A fuel injection port for injecting fuel into the intake port where the gas flow is formed;
An engine characterized by comprising The engine according to claim 1, wherein the gas injection port is disposed on a wall surface above a center line of the intake port. The engine according to claim 1, wherein the gas injection port injects the gas between a stem base end portion of the intake valve and the cylindrical shaft. The engine according to any one of claims 1 to 3, wherein the fuel injection port is disposed on a wall surface above a center line of the intake port and upstream of the gas injection port. . The engine according to any one of claims 1 to 3, wherein the fuel injection port is disposed on a wall surface below a center line of the intake port. The intake port has a siamese shape in which one passage is branched toward the plurality of openings,
The engine according to any one of claims 1 to 5, wherein the fuel injection port injects the fuel toward a branch point of the intake port. The engine according to claim 1, wherein the gas injected from the gas injection port is a part of exhaust of the engine. The fuel injection port stops fuel injection at least until the intake valve is opened in an intake stroke, and starts the fuel injection after the intake valve into which the gas flows into the cylinder is opened. The engine according to any one of claims 1 to 7.

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