JP2008175187A - Fuel injection system for cylinder injection engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To normally burn fuel in a cylinder of an engine, under low temperature. <P>SOLUTION: A fuel injection system for a cylinder injection engine comprises: a piston 18 cooperating with a cylinder 16 and forming a combustion chamber 20; an ignition plug 24 disposed to an upper part of the combustion chamber 20; and an injector 22 injecting fuel from a side part of the combustion chamber 20. The fuel injection system further comprises a fuel injection control means 12 controlling injection timing of fuel of the injector 22. The fuel injection control means 12 is constituted so that timing of fuel injection is set at a compression stroke during cold engine. The injector 22 includes: a first injection port injecting fuel so that fuel is sprayed near an electrode 72b of the ignition plug 24, with a space of a predetermined distance L; and a second injection port injecting the fuel to be close to a piston 18, compared with the first injection port. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel injection device for an in-cylinder injection engine that directly injects fuel into a cylinder, and belongs to the technical field of engine control for controlling an engine by controlling fuel injection.

  Conventionally, in an in-cylinder injection engine, fuel is injected from the side into a combustion chamber formed by the cooperation of a cylinder and a piston by a fuel injection valve (injector) in an intake stroke, and is arranged at the top of the combustion chamber. It is ignited and burned by a spark discharge caused between the two electrodes of the spark plug.

  At this time, the fuel injection direction by the injector is set to the direction of the intake valve into which the air flows so that the fuel spreads throughout the cylinder during the intake stroke.

  However, in such a case, the engine is in a cold state, and at the ignition retard timing for warming up the catalyst, there is a shortage of fuel around the electrode of the spark plug (the mixture is diluted), causing spark discharge. Even did not ignite.

  As a countermeasure, for example, an injector called a multi-hole injector as described in Patent Document 1 has a plurality of injection ports for injecting fuel. This is configured such that each of the plurality of injection ports injects fuel in different directions, and at least one injection port is set to directly inject fuel between the two electrodes of the spark plug. . Thereby, sufficient fuel is supplied to the periphery of the electrode of the spark plug to suppress the dilution of the air-fuel mixture.

JP-T-2004-519617

  However, when the above-described multi-hole injector is used, when the engine is started, particularly when the engine is in a cold state, the fuel directly injected toward the electrode of the spark plug may adhere to the electrode in a liquid state. . A so-called spark plug may become wet, or so-called smoldering of carbon resulting from attached fuel may occur, and normal spark discharge may not occur. In addition, smoke is easily generated due to this. This is because the temperature inside the spark plug and the cylinder is low, so that the fuel cannot be sufficiently vaporized until it reaches the electrode of the spark plug or does not become fine particles.

  Then, this invention makes it a subject to provide the fuel-injection apparatus of the cylinder injection type engine which can burn a fuel reliably, even if an engine is a cold state.

  In order to solve the above-described problems, the invention according to claim 1 of the present application is directed to a piston that forms a combustion chamber in cooperation with a cylinder, a spark plug disposed at an upper portion of the combustion chamber, and a side portion of the combustion chamber. A fuel injection device for a cylinder injection engine having an injector for injecting fuel from a fuel injection control means for controlling fuel injection timing of the injector, wherein the fuel injection control means When in a state, the fuel injection timing is set to the compression stroke, and the injector injects the fuel so that the fuel spray comes close to the electrode of the spark plug with a predetermined distance. A first injection port and a second injection port for injecting fuel to the piston side as compared with the first injection port are provided.

  According to a second aspect of the present invention, in the fuel injection device for an in-cylinder injection engine according to the first aspect, the injector includes a plurality of the first injection ports.

  Furthermore, the invention according to claim 3 is the fuel injection device for a direct injection type engine according to claim 2, wherein the first and second injection ports are in a plane perpendicular to a predetermined reference axis. When the point where the injection direction lines of the first injection ports intersect is the first intersection point, and the point where the injection direction lines of the second injection port intersect is the second intersection point, between the adjacent first intersection points The injection direction is set so that the distance is shorter than the distance between the first intersection and the second intersection that are adjacent to each other. Here, the central axis of the injector is assumed as the reference axis.

  Furthermore, the invention according to claim 4 is the fuel injection device for a direct injection type engine according to any one of claims 1 to 3, wherein the injector is a piston as compared with the second injection port. A third injection port for injecting fuel on the side is provided.

  In addition, according to a fifth aspect of the present invention, in the fuel injection device for an in-cylinder injection engine according to the fourth aspect, the injector includes a plurality of the third injection ports.

  In addition, according to a sixth aspect of the present invention, in the fuel injection device for a direct injection engine according to the fifth aspect, the plurality of third injection ports are in a plane perpendicular to the reference axis. The injection direction is set so that the distance between the adjacent third intersections is longer than the distance between the adjacent first intersections when the point at which the injection direction lines intersect is the third intersection. It is characterized by that.

  In addition, according to a seventh aspect of the invention, in the fuel injection device for an in-cylinder injection engine according to the fifth aspect, the plurality of third injection ports are in a plane perpendicular to the reference axis. The injection direction is set so that the distance between the adjacent third intersections is shorter than the distance between the adjacent first intersections when the point where the injection direction lines intersect is the third intersection. It is characterized by that.

  According to the first aspect of the present invention, the first spray port of the injector does not inject directly toward the electrode of the spark plug, but the fuel spray is spaced a predetermined distance from the electrode of the spark plug. Inject fuel so that it is close. Also, when the engine is in a cold state, fuel injection is performed during the compression stroke. With these, while suppressing the wetting of the electrode and carbon smoldering due to the liquid fuel adhering to the electrode of the spark plug, an appropriate amount of fuel that does not misfire to the region including the electrode of the spark plug and its surroundings is provided. It can be supplied (a weak stratification of the air-fuel mixture), and the ignitability is improved even at the retard ignition timing for speeding up the catalyst warm-up.

  Further, the second injection port of the injector injects fuel to the piston side as compared with the first injection port, so that the fuel can be diffused throughout the combustion chamber and the injection timing can be advanced to achieve sufficient vaporization. By making it possible to secure the time, the generation of smoke due to incomplete combustion in the rich mixture portion is suppressed, and these ensure good combustion even when the engine is cold. Will be realized.

  According to the second aspect of the present invention, since the injector includes a plurality of first injection ports, the fuel concentration in the region including the electrode of the spark plug and the periphery thereof increases, and the first injection port The ignitability is improved as compared with the case of one.

  Furthermore, according to the invention of claim 3, the injection direction line of the first injection port intersects the injection direction of the first and second injection ports with respect to a plane perpendicular to the predetermined reference axis. The first intersection and the second intersection where the distance between the adjacent first intersections is adjacent, where the point is the first intersection and the point where the injection direction lines of the second injection ports intersect is the second intersection Is set so as to be shorter than the distance between the first fuel injection port and the fuel injected from the plurality of first injection ports (upper combustion chamber) and the fuel injected from the single second injection port. A pressure difference in the direction in which the former is lower than the latter is generated based on the difference in flow velocity between the moving location (lower combustion chamber), and a part of the fuel injected from the second injection port is in the combustion chamber. It is drawn from the bottom to the top.

  As a result, a part of the fuel injected from the second injection port moves toward the electrode of the electrode plug to improve ignitability, and a flow is formed in which the fuel moves from the lower part to the upper part in the combustion chamber. Fuel is more diffused throughout the combustion chamber. In addition, if it supplements, if the distance between the 1st intersection which adjoins contrary to the above is longer than the distance between the 1st intersection which adjoins, and the 2nd intersection, it will be injected from the 2nd injection hole. The fuel is not drawn to the upper part of the combustion chamber.

  Furthermore, according to the invention described in claim 4, the injector includes the third injection port for injecting fuel to the piston side as compared with the second injection port, whereby the fuel is injected into the entire combustion chamber. Can be diffused.

  In addition, according to the fifth aspect of the present invention, the injector includes a plurality of third injection ports, and as a result, more fuel is supplied to the combustion chamber than in the case where there is one third injection port. It can be diffused as a whole. Specifically, a large amount of fuel can be supplied near the piston, the amount of fuel in the upper portion of the combustion chamber injected from the first and second injection ports, and the combustion chamber injected from the plurality of third injection ports The difference from the amount of fuel in the lower portion becomes smaller, that is, the fuel distribution in the entire combustion chamber becomes substantially uniform.

  In addition, according to the invention described in claim 6, the injection direction lines of the third injection ports intersect the injection direction of the plurality of third injection ports with respect to a plane orthogonal to the predetermined reference axis. Since the point is set as the third intersection point, the distance between the adjacent third intersection points is set to be longer than the distance between the adjacent first intersection points. The fuel injected from the third injection port is diffused over the entire top surface of the piston. Therefore, it is possible to prevent the fuel from adhering to the portion of the piston top face from being intensively injected.

  On the other hand, according to the seventh aspect of the present invention, the injection direction of the plurality of third injection ports is defined by the point where the injection direction line of the third injection port intersects the plane orthogonal to the predetermined reference axis. Since the third intersection is set so that the distance between the adjacent third intersections is shorter than the distance between the adjacent first intersections, the fuel injected from the plurality of third injection ports is Collectively, the flow becomes a large penetration, the flow changes direction along the top surface of the piston, and the flow of the fuel injected from the second injection port toward the electrode of the spark plug. As a result, a sufficient amount of fuel is supplied to the region including the electrode of the spark plug and its periphery, and high ignitability is ensured.

  FIG. 1 schematically shows a control system of an engine including a fuel injection device according to an embodiment of the present invention.

  FIG. 1 shows a multi-cylinder engine 10 and an engine control unit (ECU) 12 that controls the engine 10.

  In FIG. 1, the engine 10 in which one cylinder 16 is shown in a cross section viewed from the axial direction of the output shaft 14 is a so-called in-cylinder injection engine. The engine 10 includes an injector 22 that injects fuel into a combustion chamber 20 formed by the cooperation of a cylinder 16 and a piston 18, an ignition plug 24 for burning the fuel in the combustion chamber 20, and air in the combustion chamber 20. And an exhaust passage 28 for exhausting the exhaust gas in the combustion chamber 20.

  The engine 10 also includes an intake valve 30 and an exhaust valve 32 for executing a combustion cycle including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.

  The ECU 12 is configured to control the combustion of the fuel in the combustion chamber 20 by controlling the injector 22 and the spark plug 24. Specifically, the ECU 12 outputs a control signal to the injector 22 and the spark plug 24. It is configured. Further, it is configured to receive a signal from a water temperature sensor 36 that detects the temperature of the cooling water 34 of the engine 10.

  The ECU 12 is configured to set the timing of the control signal output to the injector 22 (that is, the timing of fuel injection) based on the signal from the water temperature sensor 36.

  Specifically, when the signal indicating that the engine 10 is in a predetermined cold state (specifically, a signal corresponding to a predetermined temperature or lower) is output from the water temperature sensor 36, the ECU 12 The injector 22 is controlled so that the injection timing is in the compression stroke. Otherwise, the injector 22 is controlled so that the fuel injection timing is in the intake stroke.

  Here, the “predetermined cold state of the engine” refers to a state where the engine is at a temperature substantially equal to the outside air and the catalyst is not warmed (not activated). For example, this corresponds to a state when an engine that has been stopped for a long time is started.

  When the engine is in a cold state, the reason for setting the timing for injecting fuel during the compression stroke is to collect an air-fuel mixture that easily ignites around the plug so that the ignition timing can be retarded. By setting the fuel injection timing during the compression stroke when the engine is in a cold state, ignition retard can be performed, exhaust temperature can be raised, catalyst warm-up can be accelerated, and HC emissions are suppressed.

  The ECU 12 is configured to output a control signal to the spark plug 24 during the compression stroke to the expansion stroke (so as to ignite the fuel during the compression stroke to the expansion stroke). When the engine 10 is in a cold state, that is, when fuel is injected into the cylinder 16 during the compression stroke, the ignition timing is retarded compared to when the fuel is injected into the cylinder 16 during the intake stroke. The ECU 12 may be configured as described above.

  FIG. 2 shows an enlarged view of the combustion chamber 20, and FIG. 3 shows a cross-sectional view of the tip of the injector 22.

  As shown in FIG. 2, the injector 22 is arranged in the engine 10 so as to inject fuel into the combustion chamber 20 from the side thereof.

  As shown in FIGS. 2 and 3, the injector 22 is configured to inject fuel in a plurality of directions A <b> 1 to A <b> 2, B, and C <b> 1 to C <b> 4 toward the center of the combustion chamber 20. Yes. When viewed from the axial direction of the output shaft 14, the injection directions A1 and A2, C1 and C4, and C2 and C3 appear to overlap as shown in FIGS.

  Specifically, as shown in FIG. 3, the injector 22 is an injection port formed in an injector head 50 provided at the tip thereof for injecting fuel in the injection directions A <b> 1 to A <b> 2. 52a to 52b, an injection port for injecting fuel in the injection direction B (corresponding to the second injection port described in claims), and an injection direction. There are injection ports (corresponding to the third injection ports described in claims) 56a to 56d for injecting fuel into C1 to C4. That is, the injector 22 is a multi-hole injector having a total of seven injection ports.

  The injector 22 stores high-pressure fuel supplied from a fuel pump (not shown) in a space 58 in the injector head 50, and interrupts communication between the space 58 and the plurality of injection ports 52a to 52b, 54, 56a to 56d. The needle valve 60 is configured to inject fuel by connecting the injection port and the space by retreating in the direction of the central axis CL (moving to a dotted line position). The injector 22 is configured to retract the needle valve 60 based on a control signal from the ECU 12.

  The angles of the plurality of injection directions A1 to A2, B, and C1 to C4 are set with the central axis CL of the needle valve as a reference axis (corresponding to a predetermined reference axis described in claims). The injection directions A1 and A2 are set in the direction of the angle α on the spark plug 24 side with respect to the reference axis CL. Further, the injection direction B is set so as to substantially coincide with the reference axis CL direction. Further, the injection directions C1 and C4 are set in the direction of the angle β on the piston 18 side with respect to the reference axis CL. Furthermore, the injection directions C2 and C3 are set in the direction of the angle γ (γ> β) on the piston 18 side with respect to the reference axis CL.

  From a different point of view, the injection direction B is set to the direction of the angle α on the piston 18 side with respect to the injection direction A1 (A2), and the injection directions C1 and C4 are on the piston 18 side with respect to the injection direction A1 (A2). The direction of the angle (α + β) is set, and the injection directions C2 and C3 are set to the direction of the angle (α + γ) on the piston 18 side with respect to the injection direction A1 (A2).

  Returning to FIG. 2, the injector 22 is arranged in the engine 10 so that all the injection directions are directed toward the piston 18, and the injection directions A1 and A2 of the injection ports 52a and 52b are as shown in FIG. This is the direction in which the fuel is injected most toward the spark plug 24 as compared with the injection direction.

  Further, the injection directions A1 and A2 of the injection ports 52a and 52b are set so that the shortest distance between the injection direction A1 and A2 axis of the injection ports 52a and 52b and the electrode 72b of the spark plug 24 is a predetermined distance L. ing.

  The predetermined distance L will be described. In general, the fuel injected from the injection port diffuses radially around the injection direction axis while moving in the injection direction. Therefore, for the injection ports 52a and 52b, even when the injection directions A1 and A2 are not directly directed to the electrode 72b, liquid fuel spray may adhere to the electrode 72b when the engine 10 is in a cold state. is there. Considering this, the predetermined distance L is a distance obtained so that the liquid fuel spray does not adhere to the electrode 72b.

  The injection directions B and C1 to C4 are set in a direction in which the fuel injected from the injection ports 54 and 56a to 56d is directed to the concave portion (cavity) 76 formed in the top surface 74 of the piston 18 (shown in FIG. 3). The angles β and γ are set.) The cavity 76 functions as a guide for changing the moving direction of the fuel that has moved to the cavity 76 toward the ignition plug 24. Thereby, the fuel injected from the injection ports 54 and 56a to 56d is moved to the electrodes 72a and 72b of the spark plug 24.

  Further, the injector 22 is disposed in the engine 10 such that the injection direction B of the injection port 54 intersects the spark plug 24 side with an angle θ with respect to the plane Ph orthogonal to the center line of the combustion chamber 20.

  The angle θ is determined in consideration of the combustion stability when the fuel is injected during the compression stroke and the amount of smoke generated. FIG. 4A shows the relationship between the combustion stability when the fuel is injected during the compression stroke, the amount of smoke generated and the angle θ.

  As shown in FIG. 4 (a), the combustion stability decreases as the angle θ decreases (prone to misfires), and decreases even when the angle θ increases excessively. Assuming that the fuel is injected from a predetermined position on the side of the combustion chamber 20, the smaller the angle θ is, the more the injection timing is delayed in order to direct the fuel to the spark plug 24 in the cavity 76 (the piston position is increased). The fuel injected from the injection port 54 in the injection direction B reaches the position between the two electrodes 72a and 72b of the spark plug 24, that is, the position at which spark discharge occurs. The earlier it reaches, the shorter the time until it is injected and vaporized, so that the fuel that has reached the electrodes 72a and 72b contains more liquid fuel. As a result, the surfaces of the electrodes 72a and 72b are covered with the liquid fuel, and the spark discharge cannot be surely performed, and misfire is likely to occur.

  On the other hand, as the angle θ increases, the fuel injected from the injection port 54 in the injection direction B moves a long distance while changing the direction until it reaches between the two electrodes 72a and 72b of the spark plug 24. Therefore, the amount is reduced. As a result, the fuel in a predetermined region centered between the electrodes 72a and 72b of the spark plug 24 becomes lean and cannot be ignited reliably. The predetermined region is a region in the vicinity of the electrode and affects the ignitability of the fuel.

  Further, the amount of smoke generated decreases as the angle θ increases. Smoke is generated by incomplete combustion of fuel, which is caused by excessive supply of fuel to a predetermined region centered between the electrodes 72a and 72b of the spark plug 24. As the angle θ becomes smaller, the injection timing becomes retarded, and a lot of fuel that is insufficiently vaporized reaches a region centered between the electrodes 72a and 72b of the spark plug 24, so the amount of smoke increases.

  Taking these into consideration, the angle θ is determined within the range indicated by the oblique lines in FIG. 4A, that is, within the range where the combustion stability is high and the amount of smoke generated is acceptable.

  Further, the angle θ is determined based on the timing of fuel injection in the compression stroke, in other words, the position of the piston 18.

  FIG. 4B shows the angle θ, the position of the piston 18, and the air-fuel ratio (A / F) in a predetermined region (near the electrode) centered between the electrodes 72a and 72b of the spark plug 24. Show. As shown in the figure, in order to direct the spray of the angle θ to the plug through the cavity, the injection timing becomes retarded when the angle θ decreases, so the air-fuel ratio in the predetermined region becomes excessive. Conversely, when the angle θ increases, the injection timing becomes the advance side, and the air-fuel ratio in the predetermined region becomes lean. As a result, the air-fuel ratio in a predetermined region centered between the electrodes 72a and 72b of the spark plug 24 is reduced so that the range of ignition in which fuel combustion can be normally performed, and the range indicated by hatching in the figure is reduced. . Therefore, the angle θ is determined so that the range of the ignition timing (piston position) that can be ignited becomes large.

  In summary, the injection ports 52a, 52b, and 54 that inject in the injection directions A1, A2, and B prevent the liquid fuel from adhering directly to the electrode of the spark plug, and in the region including the electrode of the spark plug and its surroundings. The injection ports 56a to 56d that supply a sufficient amount of fuel that does not misfire and inject in the injection directions C1 to C4 inject fuel to the piston 18 side compared to the injection ports 52a, 52b, and 54, thereby allowing the combustion chamber 20 to Fuel is diffused throughout. As a result, normal combustion can be performed.

  The fuel injection direction described so far is a direction on a plane orthogonal to the output shaft 14 of the engine 10 shown in FIG. Actually, the plurality of fuel injection directions A1 to A2, B, and C1 to C4 are planes Pv orthogonal to the reference axis CL as shown in FIG. 5 (corresponding to the planes described in the claims). Are set to intersect at different intersections. In the XYZ coordinate system shown in the figure, the X-axis direction is the reference axis CL direction, and the Y-axis direction is the axial direction of the output shaft 14 of the engine 10, that is, the direction orthogonal to the paper surface of FIGS.

  As shown in FIG. 5, the intersections of the injection directions A1 to A2, B, and C1 to C4 with respect to the plane Pv are Pa1, Pa2, Pb, Pc1, Pc2, Pc3, and Pc4 (Pa1 and Pa2 are claims) And Pb corresponds to the second intersection, and Pc1 to Pc4 correspond to the third intersection).

  FIG. 6A shows the positional relationship on the plane Pv between the intersections Pa1, Pa2, Pb, Pc1, Pc2, Pc3, and Pc4.

  As shown in FIG. 6A, on the plane Pv, the distance d1 between the intersections Pa1 and Pa2 is shorter than the distance between Pa1 and Pb (the distance between Pa2 and Pb) d2. , Injection directions A1 to A2. B is set. Accordingly, a location relatively above the combustion chamber 20 where the fuel injected from the injection ports 52a and 52b moves in the injection directions A1 and A2, and a combustion chamber where the fuel injected from the injection port 54 moves in the injection direction B. A pressure difference is generated between the lower position and the fuel 20 injected in the injection direction B from the injection port 54 toward the upper portion of the combustion chamber 20. This occurs when the air between the fuels injected from the two injection ports 52a and 52b flows at a high speed and the pressure at that location drops. As a result, a part of the fuel injected in the injection direction B from the injection port 54 drawn at the upper part of the combustion chamber 20 is moved toward the electrodes 72a and 72b of the spark plug 24, and the ignitability is improved. Further, a flow from the bottom to the top is formed in the combustion chamber 20, whereby the fuel is diffused throughout the combustion chamber 20. It should be noted that the injection directions A1 to A2... Are such that the distance d1 between the intersections Pa1 and Pa2 is longer than the distance between Pa1 and Pb (the distance between Pa2 and Pb) d2 on the plane Pv. If B is set, these two effects do not occur.

  Further, the distance d3 between each of the intersections Pc1 to Pc4 and Pb is made larger than d2. This is to prevent the fuel injected from the injection port 54 in the injection direction B from being pulled downward by a force more than the above-described upward pull.

  Further, as shown in FIG. 6A, the distance d1 between the intersections Pa1 and Pa2 on the plane Pv is the distance between Pc1 and Pc2 (the distance between Pc2 and Pc3, Pc3 and Pc4, Between the injection directions A1 to A2. C1 to C4 are set. As a result, as shown in FIG. 7A, when the cylinder 16 is viewed from the spark plug 24 side, the fuel injected from the injection ports 56a to 56d in the injection directions C1 to C4 diffuses throughout the cylinder 16. Therefore, the fuel injected from the injection ports 56a to 56d in the injection directions C1 to C4 hits the entire top surface 74 of the piston 18, and as a result, the fuel is intensively injected to a part of the top surface 74 of the piston 18. The contact with the fuel prevents the fuel from adhering to the portion.

  While the present invention has been described with reference to the above-described embodiment, the present invention is not limited to this.

  For example, in order to supply more fuel to the two electrodes of the spark plug and the periphery thereof, while the above-described embodiment aims to suppress the fuel from adhering to the top surface of the piston, As shown in FIG. 6B, the distance d1 between the intersections Pa1 and Pa2 on the plane Pv is the distance between Pc1 and Pc2 (the distance between Pc2 and Pc3, between Pc3 and Pc4). Of the injection directions A1 to A2. C1 to C4 may be set.

  Thereby, as shown in FIG.7 (b), the fuel injected in the injection directions C1-C4 gathers, and becomes a flow with a large penetration, The flow changes a direction along the cavity of the top surface of a piston, The fuel injected in the injection direction B flows toward the spark plug electrode. As a result, a sufficient amount of fuel is supplied to the region including the electrode of the spark plug and its periphery, and high ignitability can be ensured.

  In addition, the first injection ports for injecting fuel around the electrodes of the spark plug at the plurality of injection ports are the two injection ports 52a and 52b in the above-described embodiment, but may be more than that. Or one. If the number of second and third injection ports is constant, the more first injection ports, the more fuel can be supplied around the electrodes. However, if excessive fuel is supplied around the electrode of the spark plug, a large amount of smoke may be generated. Therefore, the number of the first injection ports is preferably two.

  Moreover, although the 3rd injection port was four injection ports 56a-56d in the above-mentioned embodiment, it may be more than that and may be one. If the number of the first and second injection ports is constant, the more third injection ports, the more fuel can be supplied to the piston side. However, because of the structure of the injector, that is, the total amount of fuel injected from the plurality of injection ports is constant, if the third injection port is increased, the fuel injected from the first and second injection ports is reduced. The fuel around the spark plug electrode can be diluted. In view of this, it is preferable that the number of the third injection ports be substantially the same as the total number of the first injection ports and the second injection ports. The fuel distribution is substantially uniform throughout the chamber.

  Finally, the above-described embodiment is an injector having seven injection ports. However, when the engine, which is the subject of the present invention, is in a low temperature state, the fuel is surely burned normally. This is achieved if there is an injection port and one second injection port. That is, one first injection port supplies a sufficient amount of fuel that does not misfire to the region including the electrode of the spark plug and its surroundings while suppressing liquid fuel from adhering to the electrode of the spark plug, One second injection port injects fuel toward the piston as compared with the first injection port, thereby diffusing the fuel throughout the combustion chamber. As a result, even if the engine is in a cold state, the fuel can be reliably burned normally.

1 is a schematic view of an engine control system including a fuel injection device for a direct injection engine according to an embodiment of the present invention. It is an enlarged view of a combustion chamber. It is an enlarged view of the tip of an injector. It is a figure which shows the relationship between angle (theta) shown in FIG. 2, combustion stability, and the amount of smoke, and the relationship between angle (theta), A / F of a plug position, and fuel injection timing. It is a perspective view which shows the injection direction of the fuel injected from an injector. It is a figure which shows the positional relationship of the injection direction of a fuel. It is a figure which shows the injection direction of the fuel seen from the spark plug side.

Explanation of symbols

16 cylinders 18 pistons 20 combustion chambers 22 injectors 24 spark plugs 72b electrodes

Claims (7)

A fuel injection device for an in-cylinder injection engine having a piston that forms a combustion chamber in cooperation with a cylinder, a spark plug disposed at an upper portion of the combustion chamber, and an injector that injects fuel from a side portion of the combustion chamber. And
A fuel injection control means for controlling the fuel injection timing of the injector;
The fuel injection control means is configured to set the fuel injection timing to the compression stroke when the engine is cold.
The injector has a first injection port for injecting fuel so that the fuel spray comes close to the electrode of the spark plug with a predetermined distance, and injects the fuel to the piston side compared to the first injection port. A fuel injection device for a direct injection type engine, comprising: The fuel injection device for a direct injection engine according to claim 1,
The fuel injector for a direct injection engine, wherein the injector includes a plurality of the first injection ports. The fuel injection device for a direct injection engine according to claim 2,
In the first and second injection ports, a point at which the injection direction line of the first injection port intersects a plane orthogonal to a predetermined reference axis is a first intersection, and an injection direction line of the second injection port Is the second intersection, the injection direction is such that the distance between the first intersections adjacent to each other is shorter than the distance between the first intersection and the second intersection adjacent to each other. A fuel injection device for a direct injection engine characterized by being set. The fuel injection device for a direct injection engine according to any one of claims 1 to 3,
The injector has a third injection port for injecting fuel to the piston side as compared to the second injection port. The fuel injection device for a direct injection engine according to claim 4,
The fuel injector for a direct injection engine, wherein the injector includes a plurality of the third injection ports. The fuel injection device for an in-cylinder injection engine according to claim 5,
In the plurality of third injection ports, when a point where the injection direction line intersects a plane orthogonal to the reference axis is a third intersection point, the distances between the adjacent third intersection points are adjacent to each other. A fuel injection device for a direct injection engine, wherein an injection direction is set to be longer than a distance between first intersections. The fuel injection device for an in-cylinder injection engine according to claim 5,
In the plurality of third injection ports, when a point where the injection direction line intersects a plane orthogonal to the reference axis is defined as a third intersection point, distances between adjacent third intersection points are adjacent to each other. A fuel injection device for a direct injection engine, wherein an injection direction is set to be shorter than a distance between the first intersections.

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