JP6641750B2 - engine - Google Patents

Description

  The present invention relates to an engine provided with an EGR system for introducing a part of exhaust gas into an intake system.

  2. Description of the Related Art 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 has been known. That is, the exhaust passage and the intake passage are connected by an EGR passage, and part of the exhaust gas is introduced into the cylinder again as EGR gas. In recent years, in such an EGR system, a system in which an outlet of an EGR passage is set to 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 and fuel mixture and the EGR gas are more likely to be introduced into the cylinder while being separated in layers, and the combustion state in the cylinder Can be stabilized (see Patent Document 1).

JP 2009-121366 A

  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 the fuel injection is performed in the exhaust stroke in which the intake valve is closed, the vaporized fuel stays in the intake port. Thereafter, 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 and the EGR gas remaining in the intake port are introduced into the cylinder while being mixed. As a result, it is difficult to form a stratified state of the mixture of the fuel and the fresh air 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 fuel spray and EGR gas. Note that such a problem may also occur when air (fresh air) is injected into the intake port instead of the EGR gas.

  One of the objects of the present invention has been made in view of the above problems, and it is an object of the present invention to provide an engine that suppresses the mixing of fuel and gas and improves the combustion state in a cylinder. It is to be noted that the present invention is not limited to this purpose, and is an operation and effect derived from each configuration shown in “Embodiments for Carrying Out the Invention” described later. Can be positioned as an objective.

(1) The engine disclosed herein includes an intake valve that opens and closes a cylinder-side opening of an intake port, an exhaust valve that opens and closes a cylinder-side opening of an exhaust port, and a fuel that injects fuel into the intake port. And an injection port. In addition, a gas injection port is provided for injecting gas in the intake port toward a direction along the back surface of the head of the intake valve and the surface of the head of the exhaust valve when the intake valve is opened. The gas injection port injects the gas toward the center of the cylinder-side opening of the intake port where the stem base end of the intake valve is located when the intake valve is closed . The fuel injection port injects the fuel toward the center of the cylinder-side opening of the intake port where the stem base end of the intake valve is located when the intake valve is closed . The gas injected from the gas injection port includes EGR gas and air (fresh air).

(2) It is preferable that the gas injection port injects the gas downward into the cylinder. The term “downward” as used herein refers to the side where the piston of the engine is located (the side opposite to the side where the intake valve and the exhaust valve are located) in the direction in which the cylinder axis of the cylinder extends. Means that
(3) Preferably, the gas injection port is provided on a wall surface below a center line of the intake port.

(4) It is preferable that the gas injection port is arranged adjacent to the back surface of the umbrella portion when the intake valve is closed .

( 5 ) It is preferable that the gas injection port is disposed downstream of the fuel injection port. The “downstream side” here means that it is closer to the opening with respect to the center line of the intake port. For example, comparing the position of the foot of the perpendicular extending from the gas injection port to the center line and the position of the foot of the perpendicular extending from the fuel injection port to the center line, the former is closer to the opening than the latter. When it is on the near side, it is assumed that the gas injection port is located downstream of the fuel injection port.

( 7 ) It is preferable that the gas injection port is provided on a wall surface facing the fuel injection port with a center line of the intake port interposed therebetween.
In this case, it is preferable that the gas injection port is disposed on an outer wall surface at a bent portion of the intake port, and the gas injection direction is a direction along the outer wall surface of the intake port. On the other hand, it is preferable that the fuel injection port is disposed on an outer or inner wall surface at a bent portion of the intake port. It is preferable that a direction of fuel injection from the fuel injection port is a direction toward the gas flowing along the outer wall surface.

  According to the disclosed engine, mixing of fuel (or a mixture of fuel and air) and gas (eg, EGR gas) injected from a gas injection port can be suppressed, and the combustion state in the cylinder can be improved. can do.

It is a typical sectional view showing the structure of the engine as an embodiment. It is a cylinder top view of an engine. It is a perspective view which shows the distribution state of an exhaust flow typically. (A) is a graph which shows a valve lift, (B) is a graph which shows valve opening acceleration. FIG. 2 is a schematic cross-sectional view of an engine (early in an intake stroke). FIG. 2 is a schematic sectional view of an engine (during fuel injection). FIG. 3 is a schematic sectional view of an engine (middle stage of an intake stroke).

  An engine as an embodiment will be described with reference to the drawings. Note that the embodiments described below are merely examples, and there is no intention to exclude various modifications and application of technology not explicitly described in the following embodiments. Each configuration of the present embodiment can be variously modified and implemented without departing from the spirit thereof. Further, they can be selected as needed, 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 arranged such that the center axis of the cylinder is vertical (a state in which the intake port and the exhaust port are located above).

[1. Constitution]
[1-1. engine]
FIG. 1 shows an engine 20 of the present embodiment. The engine 20 is a gasoline engine provided with an EGR system (exhaust gas recirculation system) for circulating a part of the exhaust gas into the intake port 1 of the cylinder head 21. The top surface 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 joined in a triangular roof shape. On this 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. Each of the openings 2, 4, the intake valve 10, and the exhaust valve 15 is provided two in each cylinder 23. As shown in FIG. 2, the intake port 1 has a siamese shape in which one passage is branched toward two openings 2. Similarly, the exhaust port 3 also has a siamese shape in which the passages connected to the two openings 4 merge into one. Further, regarding the intake, one opening 2 and one intake valve 10 may be provided for the cylinder 23, and the intake port 1 and the exhaust port 3 may not have a siamese shape.

  The intake port 1 is connected to an exhaust return passage 5 which is one of EGR passages, and is provided with an injector 7. Here, the end opening of the exhaust return passage 5 that is open toward the intake port 1 is called an exhaust gas 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 gas recirculation port]
The exhaust gas recirculation port 6 is an example of a gas injection port that injects a gas such as EGR gas or air (outside air) into the intake port 1. It has a function of injecting it as an exhaust flow toward the opening 2 within 1. The exhaust gas recirculation port 6 of the present embodiment is an end opening of an EGR passage for introducing a part of exhaust gas into the intake port 1 without pressurizing the exhaust gas. When an EGR system that pressurizes part of the exhaust gas and introduces it into the intake port 1 is provided, the end opening of the EGR passage through which the pressurized exhaust gas flows functions as the exhaust gas recirculation port 6. May be. Further, a gas other than the exhaust gas may be injected into the intake port 1.

  The shape of the exhaust stream injected from the exhaust gas recirculation port 6 is generally a cone or fan with a small divergence angle 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 gas recirculation port 6 varies according to the exhaust pressure and the intake pressure (the internal pressure of the intake port 1). When a flow control valve (EGR valve) or a pressure reducing device is provided in the exhaust return passage 5, the pressure varies according to the opening 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 below the center line of the intake port 1 in the vertical section, and is disposed adjacent to the back surface 13 of the umbrella portion when the intake valve 10 is closed. That is, the exhaust gas recirculation port 6 is provided on the inner 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 near the wall surface of the intake port 1, but the exhaust return passage 5 is extended to the inside of the intake port 1 (near the center line), The exhaust gas recirculation port 6 may be arranged at a position slightly away from the exhaust gas recirculation port 6. Further, as shown in FIG. 2, one exhaust recirculation port 6 is provided for each of the two openings 2 in each cylinder 23, or one for each of the two openings 2.

  The direction of injection of the exhaust flow is set along the umbrella back surface 13 of the intake valve 10 in the open state and the umbrella surface 19 of the exhaust valve 15 in the closed state. That is, when the intake valve 10 is opened, the exhaust flow is introduced into the cylinder 23 while flowing along the umbrella back surface 13 of the intake valve 10, and the exhaust valve 15 is disposed near the top surface in the cylinder 23. The jet direction of the exhaust flow is set so as to flow along the umbrella portion surface 19. Thereby, while the exhaust flow is being injected, the umbrella back surface 13 of the intake valve 10 and the umbrella surface 19 of the exhaust valve 15 are covered in a curtain shape by the exhaust flow, and are injected from the injector 7. Fuel adhesion is suppressed.

  Further, the direction of injection of the exhaust flow is set at least downward toward the inside of the cylinder 23. That is, when a plane perpendicular to the cylinder axis of the cylinder 23 (for example, the top surface of the cylinder block 22 or the bottom surface of the cylinder head 21) is horizontally arranged, the exhaust return passage 5 descends toward the exhaust recirculation port 6. It is formed so as to have a gradient. This facilitates the flow of the exhaust gas injected from the exhaust gas recirculation port 6 into the cylinder 23 and also facilitates the flow along the head surface 19 of the exhaust valve 15.

  In addition, as shown in FIG. 2, the injection direction of the exhaust flow in the top view of the engine 20 is set so as to pass through at least the opening 4 closed by the exhaust valve 15. In the present embodiment, the direction of injection of the exhaust gas flow is a direction substantially perpendicular to the ridgeline of the pent roof shape, and a direction from the exhaust gas recirculation port 6 to substantially the center of the openings 2 and 4. That is, the exhaust flow is injected toward the stem 11 of the intake valve 10. Therefore, the exhaust flow injected along the outer wall surface at the bent portion of the intake port 1 collides with the stem 11 of the intake valve 10 as shown in FIG. Distribute. At this time, a part of the exhaust gas flows while diffusing in a direction away from the stem 11. The other part of the exhaust gas flows along the peripheral surface of the stem 11 to the downstream side thereof. These exhaust flows are introduced into the cylinder 23 through a gap between the head 12 of the intake valve 10 and the opening 2.

[1-3. Fuel injection port]
The fuel injection port 8 has a function of injecting fuel into the intake port 1 during an intake stroke of the engine 20. Fuel is injected into the intake port 1 where the exhaust flow is formed. The amount of fuel 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 upstream of the exhaust gas recirculation port 6 and above the center line of the intake port 1 in a longitudinal section. The fuel is injected from the upstream side of the intake port 1 toward the umbrella back surface 13 of the intake valve 10 whose surface is covered by the exhaust flow. Thereby, the adhesion of the fuel to the umbrella back surface 13 of the intake valve 10 is suppressed.

  As used herein, the term “upstream” means a position where the distance to the opening 2 is far from the center line of the intake port 1 as a reference. For example, 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 defined as a point A. On the other hand, a perpendicular is lowered from the fuel injection port 8 to the center line of the intake port 1, and the foot of the perpendicular is defined as a point B. Point B is located at a position farther from opening 2 than 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 position where the intake port 1 branches toward the two openings 2, and It is arranged almost in 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 exhaust flow” includes a direction parallel to the flow direction of the exhaust flow. In the present embodiment, the direction of fuel injection whose angle with the flow direction of the exhaust flow is within a range of about -45 ° to 45 ° is referred to as “direction along the exhaust flow”. As shown in FIG. 2, the fuel injection direction of the engine 20 with respect to each of the two openings 2 is substantially at the center of the opening 2 (the base end of the stem 11 of the intake valve 10), as shown in FIG. Two directions are set. The fuel injection direction is set to intersect the exhaust flow injection direction on the upstream side of the head 12 of the intake valve 10. As a result, 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, and a mixture of fuel and air or fuel spray is supplied to the surface layer. The exhaust gas flow is introduced into the cylinder 23.

[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 processors such as a CPU and an MPU, ROM, RAM, and nonvolatile memory are integrated. The processor is an arithmetic processing device including a control circuit, an arithmetic circuit, a cache memory, and the like. The ROM, the RAM, and the nonvolatile memory are memory devices that store programs and data during work. The control content of the control device 9 is recorded as an application program in ROM, RAM, and nonvolatile memory. When the program is executed, the contents of the program are expanded in the memory space in the RAM and executed by the processor.

The control device 9 includes a cam angle sensor 31 that detects a rotation angle (cam rotation angle) of a cam shaft that drives the intake cam 25 and the exhaust cam 26, and detects a rotation angle (crank angle) of a crankshaft of the engine 20. The crank angle sensor 32 is connected. The control device 9 controls the fuel injection amount, the injection timing, and the fuel pressure of the injector 7 based on the cam rotation angle and the crank angle.
The fuel injection timing is set at least during 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 intake valve 10 during the intake stroke. Here, the fuel injection is performed within the intake stroke (after the exhaust top dead center) and at least after the intake valve 10 is opened. That is, the fuel injection is performed in a state where the exhaust gas flow injected from the exhaust gas 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, during the intake stroke of the engine 20 and at least after a predetermined time has elapsed since the opening of the intake valve 10 [in the section between θ ₂ and θ ₅ in FIG. 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. Even if a predetermined time has elapsed since the intake valve 10 was opened, if the piston is rising (before top dead center), the burned gas (exhaust gas) in the combustion chamber is discharged to the intake port 1. Therefore, it is preferable to start fuel injection after the piston starts to descend (after top dead center).

Each of the crank angles θ ₁ , θ ₃ , and θ ₅ in FIG. 4A corresponds to the opening time, the maximum opening time, and the closing time of the intake valve 10. The crank angles θ ₂ and θ ₄ are crank angles that give an inflection point to the graph of the valve lift. 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. Controller 9 is a least the exhaust top dead center and later, after time the crank angle theta is theta _1, starts the fuel injection. As a result, mixing of the fuel and the exhaust gas in the intake port 1 is suppressed. Note that, in order to more reliably suppress the mixing of the fuel and the exhaust flow, it is preferable to shift the fuel injection start timing in a more retarded direction. The control device 9 of the present embodiment stops the fuel injection from the fuel injection port 8 until the opening acceleration changes from positive to negative in 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, so that mixing of the fuel and the exhaust flow in the intake port 1 can be suppressed. Sex is greatly increased.

The timing at which fuel injection ends can vary depending on the total fuel injection amount and fuel pressure, but it is preferable to end fuel injection within the intake stroke. For this reason, it is preferable that the fuel pressure be 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. The timing and end timing of the intake stroke is started is arbitrarily set, may be perfectly matched to the theta ₁ through? ₅ section, it may not be matched. By using a known variable valve timing mechanism, it is possible to shift the intake stroke from theta ₁ through? ₅ interval in the advance direction or the retard direction.

[2. Action]
When the intake valve 10 is opened, the internal pressure of the intake port 1 decreases to a negative pressure, and exhaust gas is injected from the exhaust gas 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 gap between the back surface 13 of the umbrella portion of the intake valve 10 and the opening 2 as indicated by a black arrow in FIG. In the cylinder 23, the exhaust flow passes through the head surface 19 of the exhaust valve 15, flows to the vicinity of the cylinder liner 24 of the cylinder block 22, and forms a swirling flow along the surface of the cylinder liner 24.

  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 gas while being mixed with the external airflow (open arrows in FIG. 6) that is drawn into the intake port 1 from the intake manifold side. At this time, since the outer surface of the swirl outside of the intake port 1 is covered in a curtain shape by the exhaust flow, the fuel is less likely to adhere to the inner wall surface of the intake port 1. Further, since the fuel injection direction is along the exhaust flow, the fuel or the air-fuel mixture is less likely to be mixed into the exhaust flow, and is introduced into the cylinder 23 on the surface layer of the exhaust flow.

  As shown in FIG. 7, the fuel in the state of being collected on the surface layer of the exhaust flow is transported along with the exhaust flow along the swirl flow also in the cylinder 23. While the exhaust gas flows along the outside (close to the wall) of the cylinder 23, the mixture containing the fuel spray and the fuel is distributed so as to flow inside the cylinder 23. At this time, a stratified state is formed in which the fuel concentration is higher inside the cylinder 23 and lower in the outside. Thereby, fuel adhesion to the cylinder liner 24 in the cylinder 23 is suppressed. Further, the fuel vaporized inside the cylinder 23 takes latent heat of vaporization from the surrounding air and the cylinder liner 24 to lower the in-cylinder temperature. Thereby, the charging efficiency and the volumetric efficiency are increased, and the knocking resistance of the engine 20 is improved.

[3. effect]
(1) In the engine 20 described above, the fuel is injected into the direction along the umbrella portion back surface 13 of the intake valve 10 and the umbrella portion surface 19 of the exhaust valve 15 so that fuel is injected. 13 can be made difficult to adhere to. As a result, fuel can be easily vaporized inside the cylinder 23, and latent heat of vaporization can be taken inside the cylinder 23. Therefore, the charging efficiency and the volume efficiency can be increased, and the knocking resistance of the engine 20 can be improved.
Further, the fuel can be introduced into the cylinder 23 in a state of being carried on the exhaust gas flow, and the fuel can be made less likely to adhere to the head surface 19 of the exhaust valve 15 and the cylinder liner 24. As a result, mixing of the fuel and the exhaust gas flow can be suppressed (or avoided), and the combustion state in the cylinder 23 can be improved.

Further, since the fuel injection is stopped until a predetermined time elapses after the intake valve 10 is opened, a conical (fan-shaped) exhaust flow may be introduced into the cylinder 23 prior to the fuel. it can. Therefore, the mixing of the fuel and the exhaust gas flow can be suppressed (or avoided), and the combustion state in the cylinder 23 can be further improved.
Further, by injecting the fuel in the intake stroke after a predetermined time has elapsed, the fuel can be introduced into the cylinder 23 on the surface layer of the exhaust flow while being mixed with fresh air. Thereby, the combustion state in the cylinder 23 can be further improved.

  (2) In the engine 20, as shown in FIG. 1, the exhaust gas recirculation port 6 is provided so as to inject the exhaust gas flow downward into the cylinder 23. Thereby, as shown in FIG. 3, it is possible to cover the umbrella back surface 13 of the intake valve 10 with the exhaust gas flow, and it is possible to suppress fuel adhesion to the intake valve 10. Further, the exhaust flow injected from the exhaust gas recirculation port 6 can be smoothly introduced into the cylinder 23, and can flow along the head surface 19 of the exhaust valve 15. Therefore, the combustion state in the cylinder 23 can be further improved.

  (3) In the engine 20, the exhaust gas recirculation port 6 is provided on the inner wall surface below the center line of the intake port 1. Thereby, as shown in FIGS. 5 to 7, it is possible to easily form an airflow from the umbrella portion back surface 13 of the intake valve 10 to the umbrella portion surface 19 of the exhaust valve 15, and to suppress fuel adhesion in the cylinder. be able to. Therefore, the combustion state in the cylinder 23 can be further improved.

(4) In the engine 20 described above, the exhaust gas recirculation port 6 is disposed adjacent to the umbrella back 13 when the intake valve 10 is closed. Thereby, it is possible to easily form an airflow along the umbrella portion back surface 13 of the intake valve 10, and it is possible to efficiently suppress fuel adhesion to the intake valve 10. In addition, since the exhaust flow flows along the umbrella back surface 13 of the intake valve 10, the exhaust flow can flow into the cylinder 23 even when the valve lift of the intake valve 10 is relatively small. . Therefore, before the fuel injection is started, the exhaust flow in the cylinder 23 as shown in FIG. 5 can be formed, and the combustion state in the cylinder 23 can be improved.
(5) In the engine 20, as shown in FIG. 3, the exhaust flow is injected toward the base end of the stem 11 of the intake valve 10. Thereby, the entire back surface 13 of the umbrella portion of the intake valve 10 can be covered with the exhaust gas flow, and the adhesion of fuel to the intake valve 10 can be suppressed.

  (6) In the engine 20, the fuel is injected in a direction along the injection direction of the exhaust flow injected from the exhaust gas recirculation port 6. Thereby, the fuel spray can be easily collected on the surface layer of the exhaust flow (easy to be put), and the mixing of the fuel and the exhaust flow can be efficiently suppressed. Therefore, the combustion state in the cylinder 23 can be further improved. In addition, since the fuel easily flows in the cylinder 23 along the exhaust flow, the amount of fuel adhering to the cylinder liner 24 can be reduced.

  (7) In the engine 20, 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 in-cylinder direct injection rate of the fuel increases, the intake air cooling effect in the cylinder 23 can be enhanced.

[4. Modification]
In the above-described embodiment, the engine 20 having the exhaust gas recirculation port 6 for injecting the EGR gas in the intake port 1 is exemplified. In addition (or instead), air (outside air) is injected in the intake port 1. It is also possible to use a gas injection port. Even in this case, effects similar to those of the above-described embodiment can be obtained.

  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. Further, in a multi-port type engine, it is also possible to apply the present invention to an engine having an independent intake port 1 in each of two openings 2 instead of a siamese 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, the same structure as in the above-described embodiment can be applied, and the same effect as in the above-described embodiment can be applied. Can be acquired.

REFERENCE SIGNS LIST 1 intake port 2 opening 3 exhaust port 4 opening 5 exhaust return passage 6 exhaust recirculation port 7 injector 8 fuel injection port 9 controller 10 intake valve 15 exhaust valve 23 cylinder 31 cam angle sensor 32 crank angle sensor

Claims (6)

An intake valve that opens and closes the cylinder-side opening of the intake port,
An exhaust valve for opening and closing the cylinder-side opening of the exhaust port;
A fuel injection port for injecting fuel into the intake port,
When opening the intake valve, a gas injection port for injecting gas in the intake port in a direction along the umbrella back surface of the intake valve and the umbrella surface of the exhaust valve,
The gas injection port injects the gas toward the center of the cylinder-side opening of the intake port where the stem base end of the intake valve is located when the intake valve is closed ,
The engine, wherein the fuel injection port injects the fuel toward a center of a cylinder-side opening of the intake port where a stem base end of the intake valve is located when the intake valve is closed . The engine according to claim 1 , wherein the gas injection port injects the gas downward into the cylinder. The engine according to claim 1 , wherein the gas injection port is provided on a wall surface below a center line of the intake port. The gas injection port, characterized in that it is disposed adjacent to the umbrella back side in the closed state of the intake valve engine according to any one of claims 1 to 3. The engine according to any one of claims 1 to 4, wherein the gas injection port is disposed downstream of the fuel injection port. The engine according to any one of claims 1 to 5, wherein the gas injection port is provided on a wall surface facing the fuel injection port across a center line of the intake port.

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