JP2011047341A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an unburned fuel loss and improve fuel economy, by preventing fuel spray from adhering to the upper inner wall surface of a pent roof-shaped combustion chamber. <P>SOLUTION: An outwardly-opening fuel injection valve 19 is so configured that the angle formed between the visible outline of the side of the upper inner wall surface and a cylinder axis, of the fuel spray injected toward the intake-side inclined surface 9 and exhaust-side inclined surface 11 of wall surfaces forming the combustion chamber 6, formed on a cylinder head 3, is smaller than the angle formed between the visible outline of the side of the upper inner wall surface and the cylinder axis, of the fuel spray injected along the ridge line 12 of the combustion chamber 6. The fuel spray from the fuel injection valve 19 is prevented from being brought into contact with the upper inner wall surface 7 of the pent roof-shaped combustion chamber 6, no rebound to the output of the internal combustion engine occurs, the unburned fuel loss is reduced, and the fuel economy is improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an internal combustion engine having a pent roof type combustion chamber.

  For example, in Patent Document 1, a flow restricting means is provided on the downstream side of an injection hole through which fuel is injected to suppress the reach distance of the hollow conical fuel spray injected from the injection hole in the injection hole axial direction. A fuel injection valve is disclosed.

  The flow restricting means is provided so as to cover the periphery of the top of the hollow cone-shaped fuel spray injected from the nozzle hole, and is substantially parallel to the central axis of the nozzle hole. A and a wall surface B that is substantially orthogonal to the central axis of the nozzle hole and does not come into contact with the outer edge of the fuel spray downstream spray from the nozzle hole, and the fuel injection is stopped by the action of the wall surfaces A and B. Then, the arrival distance of the fuel spray in the axial direction of the nozzle hole when a certain time has elapsed is suppressed.

JP 2002-120544 A

  However, when the fuel injection valve disclosed in Patent Document 1 is arranged at the upper center of the pent roof type combustion chamber, it is possible to suppress fuel adhesion to the piston and cylinder wall, but one of the hollow cone-shaped fuel sprays. Part of the upper inner wall surface of the pent roof type combustion chamber contacts the intake side inclined surface where the intake port opens and the exhaust side inclined surface where the exhaust port opens, and the fuel adhering to these inclined surfaces It may become unburned fuel and fuel consumption may deteriorate.

  Accordingly, the present invention provides an internal combustion engine comprising a pent roof type combustion chamber and an open-open fuel injection valve capable of injecting fuel into a hollow conical shape, wherein the fuel injection valve is along a ridge line of the combustion chamber. Compared to the angle formed by the outer axis of the upper inner wall surface of the fuel spray injected by the cylinder axis and the cylinder axis, it faces the intake side inclined surface and the exhaust side inclined surface formed on the cylinder head of the wall surface constituting the combustion chamber. The angle formed by the outer axis of the upper inner wall surface of the fuel spray injected in this way and the cylinder axis is small.

  According to the present invention, the fuel spray from the fuel injection valve can be prevented from coming into contact with the upper inner wall surface of the pent roof type combustion chamber, the unburned loss is reduced without rebounding to the output of the internal combustion engine, Fuel consumption can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which showed typically the whole structure of the internal combustion engine which concerns on this invention. 1 is a perspective view of an internal combustion engine according to the present invention. 1 is a cross-sectional view of a main part of an internal combustion engine in a fuel according to a first embodiment of the present invention, taken along a plane including a cylinder axis and a ridge line of a combustion chamber. 1 is a cross-sectional view of an essential part of an internal combustion engine in a first embodiment of the present invention, and is a cross-sectional view taken along a plane orthogonal to a ridge line of a combustion chamber and including a cylinder axis. Sectional drawing along the AA line of FIG. Sectional drawing along the BB line of FIG. Sectional drawing along CC line of FIG. Sectional drawing along the DD line | wire of FIG. Sectional drawing of the principal part of the internal combustion engine in 2nd Embodiment fuel of this invention, Comprising: Sectional drawing along the plane containing the cylinder axis and the ridgeline of a combustion chamber. Sectional drawing of the principal part of the internal combustion engine in 2nd Embodiment fuel of this invention, Comprising: Sectional drawing along the plane orthogonal to the ridgeline of a combustion chamber and containing a cylinder axis. Sectional drawing along the EE line of FIG. Sectional drawing along the FF line of FIG. Sectional drawing along the GG line of FIG. Sectional drawing along the HH line of FIG. It is principal part sectional drawing of the internal combustion engine in 3rd Embodiment fuel of this invention, Comprising: Sectional drawing along the plane containing the cylinder axis and the ridgeline of a combustion chamber. Sectional drawing of the principal part of the internal combustion engine in 3rd Embodiment fuel of this invention, Comprising: Sectional drawing along the plane orthogonal to the ridgeline of a combustion chamber and containing a cylinder axis. FIG. 17 is a cross-sectional view taken along the line II of FIG. Sectional drawing along the JJ line | wire of FIG.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view schematically showing the overall configuration of an internal combustion engine according to the present invention, and FIG. 2 is a perspective view of the internal combustion engine according to the present invention.

  The internal combustion engine in the present embodiment is a compression self-ignition internal combustion engine, and a plurality of cylinders 2 are provided in a cylinder block 1 of the internal combustion engine, and a cylinder head 3 is fixed so as to cover the upper surface thereof. ing. In the cylinder 2, a piston 4 having a cavity 5 recessed in the crown surface is slidably fitted.

  A combustion chamber 6 is configured by being covered with the cylinder block 1, the cylinder head 3, and the piston 4.

  The combustion chamber 6 is configured as a so-called pent roof type. Of the wall surfaces constituting the combustion chamber 6, the upper inner wall surface 7 formed in the cylinder head 3 is an intake air in which two intake ports 8 and 8 are opened. The side inclined surface 9, the exhaust side inclined surface 11 in which the two exhaust ports 10 and 10 are opened, and the intake side inclined surface 9 and the exhaust side inclined surface 11 are abutted to each other. Linear ridge line 12 passing through the center, intake side inclined surfaces 11 and both sides of intake side inclined surfaces 11, intake side wall surfaces 13 and 13 that are parallel to the plane including the cylinder axis, and exhaust side inclined surfaces 11. The exhaust side wall surfaces 14 and 14 that are parallel to the plane including the cylinder axis, the intake side wall surfaces 13 and 13, and the exhaust side wall surfaces 14 and 14 are positioned on the outer peripheral side, and the lower surface of the cylinder head 3 is In a plane parallel to the containing plane A first flat surface portion 15, a second flat surface portion 16 that is located on the outer peripheral side of the rising portion of the intake side inclined surface 9 and the exhaust side inclined surface 11 and is a plane parallel to the plane including the lower surface of the cylinder head 3, have.

  An opening of the intake port 8 with respect to the combustion chamber 6 is opened and closed by an intake valve 17. The opening of the exhaust port 10 with respect to the combustion chamber 6 is opened and closed by an exhaust valve 18. A fuel injection valve 19 for injecting a hollow conical fuel spray (see region M in FIG. 1) into the combustion chamber 6 is surrounded by a pair of intake valves 17 and 17 and a pair of exhaust valves 18 and 18 of each cylinder. The cylinder 2 is disposed at the approximate center position of the combustion chamber 6, in other words, on the ridge line 12 and at the approximate center position.

  The fuel injection valve 19 is an externally-opening injection valve that injects fuel when a valve body 33 (described later) projects outside a main body (described later, a nozzle body 30). The lift amount, injection pulse width, and injection timing of the valve body 33 (described later) are controlled based on the control signal from.

  The ECU 20 receives detection signals from various sensors such as an air flow meter 21 that detects the intake air intake amount, an accelerator opening sensor 22 that detects the accelerator opening, a crank signal, and a crank angle sensor 23 that detects the crank angle position. The fuel injection valve 19 is controlled based on these input signals.

  Here, in the internal combustion engine of the present embodiment, as shown in FIG. 1, during low load operation, fuel is injected from the fuel injection valve 19 into the combustion chamber 6 at the timing of compression top dead center. The fuel spray does not adhere to the inner wall surface of the combustion chamber 6.

  FIGS. 3-8 has shown principal part sectional drawing of the internal combustion engine and the principal part sectional drawing of the fuel injection valve 19 in 1st Embodiment of this invention.

  3 is a cross-sectional view of the internal combustion engine along a plane including the ridge line 12 and the cylinder axis, FIG. 4 is a cross-sectional view of the internal combustion engine along a plane orthogonal to the ridge line 12 and including the cylinder axis, and FIG. 4 is a sectional view taken along line AA in FIG. 4, FIG. 6 is a sectional view taken along line BB in FIG. 5, FIG. 7 is a sectional view taken along line CC in FIG. It is sectional drawing along the DD line.

  As shown in FIGS. 5 to 8, the fuel injection valve 19 includes a nozzle body 30 in which a circular fuel injection port 31 is formed when viewed from the axial direction of the fuel injection valve 19, and an outer periphery of the fuel injection port 31. A tapered seal surface 32 formed when viewed in a section including the axis of the fuel injection valve 19 and the fuel injection port 31 are closed by being seated on the seal surface 32, and the nozzle from the state seated on the seal surface 32 is By moving (lifting) toward the outside of the body 30, the fuel injection port 31 is separated from the seal surface 32 over the entire circumference of the fuel injection port 31, and the radial direction of the fuel injection port 31 (see FIG. 5). , And a valve body 33 that enables fuel injection in the left-right direction in FIG. 7. For example, the nozzle body 30 and the valve body 33 are circular with the axis of the fuel injection valve 19 passing through the fuel injection port 31 as the center, and when viewed in cross section, the tapered sealing surface 32 is a part of a conical surface. is there.

  The fuel injection valve 19 further includes a guide portion 34 that guides the fuel injected from the fuel injection port 31 toward the combustion chamber 6 when the valve element 33 is separated from the seal surface 32. The guide portion 34 has a fuel injection passage 35 formed between the nozzle body 30 and the valve body 33 when the valve body 33 is separated from the seal surface 32.

  As shown in FIGS. 3 and 4, the fuel injection valve 19 has a cylinder axis of fuel spray injected along the ridge line 12 from the fuel injection port 31 so that the fuel spray does not contact the upper inner wall surface 7. The cylinder of fuel spray injected from the fuel injection port 31 toward the intake side inclined surface 9 and the exhaust side inclined surface 11 as compared with the angle θ1 formed by the outer line on the upper inner wall surface viewed from the direction orthogonal to the cylinder axis The angle θ2 formed between the outer line on the upper inner wall surface viewed from the direction orthogonal to the axis and the cylinder axis is reduced. In other words, the fuel injection valve 19 has a large angle between the fuel injection direction of the fuel injection port 31 and the ridge line 12 when viewed from the cylinder axis direction (looking down from the upper side in FIGS. 3 and 4). The guide portion 34 is formed so that the fuel spray injected from the position becomes smaller in the angle formed by the outer axis on the upper inner wall surface side of the fuel spray and the cylinder axis when viewed from the direction orthogonal to the cylinder axis. Yes.

  The guide portion 34 has a position where fuel is injected from the fuel injection port 31 along the ridge line 12 and a position where fuel is injected from the fuel injection port 31 toward the intake side inclined surface 9 and the exhaust side inclined surface 11. They are formed in different shapes. In other words, in the fuel injection valve 19, the nozzle shape formed between the nozzle body 30 and the valve body 33 has a position close to the ridge line 12 and a position away from the ridge line 12 in the circumferential direction of the fuel injection port 31. It is formed differently.

  More specifically, in the first embodiment, the fuel injection passage 35 positioned on the downstream side of the fuel injection port 31 has a position where fuel is injected from the fuel injection port 31 along the ridgeline 12, and the fuel injection port 31. The guide portions 34 are formed so as to have different lengths from the positions at which the fuel is injected toward the intake side inclined surface 9 and the exhaust side inclined surface 11. More specifically, in the first embodiment, a circular nozzle body centering on the axis of the fuel injection valve 19 passing through the fuel injection port 31 at a position where fuel is injected from the fuel injection port 31 along the ridgeline 12. A notch 36 is formed on the outer periphery of the machine 30 by machining or the like, and compared with the passage length L1 of the fuel injection passage 35 at a position where fuel is injected from the fuel injection port 31 along the ridgeline 12, the intake side from the fuel injection port 31 The guide portion 34 is formed such that the passage length L2 of the fuel injection passage 35 at a position where fuel is injected toward the inclined surface 9 and the exhaust-side inclined surface 11 is increased.

  Therefore, the fuel injection valve 19 has a fuel angle as compared to the spray angle θ3 viewed from the direction perpendicular to the cylinder axis of the fuel spray injected along the ridge line 12 from the fuel injection port 31 (substantially, the fuel injection passage 35). The spray angle θ4 as viewed from the direction orthogonal to the cylinder axis of the fuel spray injected from the injection port 31 (substantially, the fuel injection passage 35) toward the intake side inclined surface 9 and the exhaust side inclined surface 11 becomes smaller. Yes. In other words, fuel spray injected from a position where the angle formed by the fuel injection direction and the ridge line 12 is large at the fuel injection port 31 when viewed from the cylinder axial direction (looking from the top to the bottom in FIGS. 3 and 4). The guide portion 34 is formed so that the angle formed between the outer line on the upper inner wall surface of the fuel spray and the outer line on the cylinder axis side of the fuel spray viewed from the direction orthogonal to the cylinder axis is small.

  Here, when the flow path diameter (passage cross-sectional area) of the fuel injection passage 35 is D and the passage length of the fuel injection passage 35 is L, the spray angle of the fuel spray decreases as the value defined by L / D increases. Therefore, the passage length of the fuel injection passage 35 is relatively long at the position where fuel is injected from the fuel injection port 31 toward the intake side inclined surface 9 and the exhaust side inclined surface 11, and the spray angle θ4 at this position is relatively large. It is getting smaller.

  When the engine 33 is under a low load when the amount of movement (lift amount) of the valve body 33 from the seal surface 32 is small and the amount of fuel injection from the fuel injection valve 19 is small, the fuel injected to the inner wall surface of the combustion chamber 6 In order to prevent adhesion, fuel is injected from the fuel injection valve 19 at a timing near the compression top dead center so as to form a stratified mixture in the combustion chamber 6, and stratified mixing is performed inside the combustion chamber 6 at a timing near the compression top dead center. When the engine is under high load when the amount of movement (lift amount) of the valve body 33 from the seal surface 32 is large and the amount of fuel injection from the fuel injection valve 19 is large, a homogeneous air-fuel mixture is introduced into the combustion chamber 6. Thus, the fuel is injected from the fuel injection valve 19 at a timing at which the fuel injection timing is advanced even during low-load operation, so that a homogeneous mixture is formed in the combustion chamber 6.

  That is, in the internal combustion engine, the amount of fuel injection injected from the fuel injection valve 19 and the mixture distribution in the combustion chamber 6 are controlled by controlling the amount of movement of the valve body 33 from the seal surface 32 by the ECU 20. When the engine is under a low load, the amount of movement of the valve element 33 from the seal surface 32 is controlled to be smaller than when the engine is under a high load, and fuel is injected into the combustion chamber 6 at a timing near the top dead center. By jetting, a stratified mixture is formed.

  In such a first embodiment, the fuel spray from the fuel injection valve 19 can be prevented from coming into contact with the upper inner wall surface 7 of the pent roof type combustion chamber 6 without rebounding to the output of the internal combustion engine, Unburnt loss can be reduced, fuel efficiency can be improved, and exhaust performance can be improved.

  Further, the guide portion 34 is orthogonal to the angles θ1 and θ2 formed by the outer axis of the upper inner wall surface viewed from the direction orthogonal to the cylinder axis of the injected fuel spray and the cylinder axis, and to the cylinder axis of the injected fuel spray. Since the spray angles θ3 and θ4 viewed from the direction to be defined are defined as described above, the pent roof type combustion is performed only by changing the shape of the guide portion 34 of the fuel injection valve 19 without changing the design of the combustion chamber 6. The fuel spray can be prevented from coming into contact with the upper inner wall surface 7 of the chamber 6 from the fuel injection valve 19.

  Furthermore, since the notch 36 of the nozzle body 30 can be easily formed by machining or the like, a position where fuel is injected from the fuel injection port 31 along the ridgeline 12, and an intake side inclined surface from the fuel injection port 31. 9 and the position where the fuel is injected toward the exhaust-side inclined surface 11, the shape of the guide portion 34 can be easily formed into different shapes.

  Here, in the present embodiment, since the cutout portion 36 is formed only in the nozzle body 30, the valve element 33 is located more than the cutout portion 36 at a position where fuel is injected from the fuel injection port 31 along the ridgeline 12. It will overhang outside. That is, in the first embodiment, the notched portion 36 is formed in the nozzle body 30, so that the overhang portion 37 is formed on the valve body 33 at a position where fuel is injected from the fuel injection port 31 along the ridgeline 12. Will be.

  As described above, when the overhang portion 37 is formed on the valve body 33, the fuel is injected from the fuel injection port 31 along the ridge line 12, and is viewed from the direction perpendicular to the cylinder axis by the action of the overhang portion 37. The angle θ5 formed by the outer line on the upper inner wall surface of the fuel spray and the cylinder axis can be relatively increased.

  And in the position which injects a fuel along the ridgeline 12 from the fuel injection port 31, since the fuel injection path 35 becomes relatively short, toward the intake side inclined surface 9 and the exhaust side inclined surface 11 from the fuel injection port 31 Although the spray angle of the fuel spray is larger than the fuel injection position, the fuel spray penetration (spray reach) is shortened, so that the fuel spray is prevented from adhering to the upper inner wall surface 7 of the combustion chamber 6. can do.

  At a position where fuel is injected from the fuel injection port 31 toward the intake-side inclined surface 9 and the exhaust-side inclined surface 11, the fuel injection passage 35 is relatively long, and the fuel is injected from the fuel injection port 31 along the ridgeline 12. Since the spray angle of the fuel spray becomes smaller than the injection position, the fuel spray penetration (spray reach distance) becomes longer, but from the fuel injection port 31 toward the intake side inclined surface 9 and the exhaust side inclined surface 11. The angle formed by the cylinder inner axis and the outer line on the upper inner wall surface viewed from the direction orthogonal to the cylinder axis of the fuel spray injected in this way is relatively small. Adhesion to the inner wall surface 7 can be suppressed.

  Further, when the engine is under a low load with a relatively small fuel injection amount, the stratified mixture in the combustion chamber 6 is kept from coming into contact with the upper inner wall surface 7 of the pent roof type combustion chamber 6 from the fuel injection valve 19. By self-igniting, it is possible to reduce cooling loss by heat insulation by an air layer formed between the upper inner wall surface 7 of the combustion chamber 6 having a low temperature. When the engine is under a heavy load with a relatively large fuel injection amount, the substantial opening area of the fuel injection valve 19 is maximized. Therefore, an increase in the injection pulse (opening time of the fuel injection valve 19) is suppressed, and the fuel By ensuring the mixing time of the spray, homogeneous combustion can be stably performed.

  In the first embodiment, the passage length of the fuel injection passage 35 is changed in the circumferential direction of the fuel injection port 31 by notching the nozzle body 30 side. However, fuel injection is performed by notching the valve body side. It is also possible to change the passage length of the passage 35 in the circumferential direction of the fuel injection port 31.

  Hereinafter, although other embodiment of this invention is described, about the component same as 1st Embodiment mentioned above, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  FIGS. 9-14 has shown principal part sectional drawing of the internal combustion engine in 2nd Embodiment of this invention, and principal part sectional drawing of the fuel injection valve 19. As shown in FIG.

  The internal combustion engine in the second embodiment has substantially the same configuration as the internal combustion engine in the first embodiment described above, but in this second embodiment, fuel is injected from the fuel injection port 31 along the ridgeline 12. The cutout portions 36 and 41 are formed on the outer periphery of the nozzle body 30 and the valve body 33 having a circular cross section by machining or the like. That is, in the second embodiment, the valve element 33 does not protrude outside the nozzle body 30 at the position where the fuel is injected from the fuel injection port 31 along the ridgeline 12, and the valve element 33 is the protruding part 37 described above. The configuration is the same as that of the first embodiment except that the configuration corresponding to is not provided.

  Also in this second embodiment, the fuel injection valve 19 injects along the ridgeline 12 from the fuel injection port 31 so that the fuel spray does not contact the upper inner wall surface 7, as shown in FIGS. Compared to the angle θ1 formed by the cylinder axis and the outer line on the upper inner wall surface viewed from the direction perpendicular to the cylinder axis of the fuel spray, the fuel injection port 31 is directed toward the intake side inclined surface 9 and the exhaust side inclined surface 11. The angle θ2 formed by the outer axis of the upper inner wall surface viewed from the direction perpendicular to the cylinder axis of the injected fuel spray and the cylinder axis is reduced.

  Also in the second embodiment, it is possible to obtain substantially the same operational effects as those of the first embodiment described above.

  Next, a third embodiment of the present invention will be described with reference to FIGS. The internal combustion engine in the third embodiment has substantially the same configuration as the internal combustion engine of the first embodiment described above, but in this third embodiment, as shown in FIG. The fuel injection from the fuel injection passage 35 to the combustion chamber 6 is performed at the circumferential position of the fuel injection valve 19 where the portion 34 injects fuel from the fuel injection port 31 toward the intake side inclined surface 9 and the exhaust side inclined surface 11. It has a shielding wall 51 that can be blocked.

  As shown in FIG. 18, the shielding wall 51 extends so as to approach the valve body 33 adjacent to the opening on the combustion chamber side of the fuel injection passage 35 and narrows the gap dimension between the nozzle body 30 and the valve body 33. Thus, the amount of movement (lift amount) from the seal surface 32 of the valve body 33 when the fuel injection amount at the time of engine low load is injected is a wall surface substantially parallel to the cylinder axis provided at the tip of the nozzle body 30. Then, in the position where fuel is injected from the fuel injection port 31 toward the intake side inclined surface 9 and the exhaust side inclined surface 11, fuel spray from the fuel injection passage 35 to the combustion chamber 6 is prevented, and the fuel injection amount at the time of high engine load As for the amount of movement (lift amount) of the valve body 33 from the seal surface 32 when injecting fuel, the fuel injection passage is located at the position where fuel is injected from the fuel injection port 31 toward the intake side inclined surface 9 and the exhaust side inclined surface 11 35 to combustion chamber 6 It is formed so as to allow the fuel spray.

  Specifically, with the amount of movement (lift amount) of the valve body 33 from the seal surface 32 at the time of engine low load, the opening on the combustion chamber side of the fuel injection passage 35 is entirely covered by the shielding wall 51. Although fuel injection is hindered, the amount of movement (lift amount) of the valve body 33 from the seal surface 32 at the time of high engine load increases the opening on the combustion chamber side of the fuel injection passage 35 to the outside of the shielding wall 51. A shielding wall 51 is formed so that fuel injection is allowed.

  Here, the width of the seal portion (cross-sectional height / gap size between the nozzle body 30 and the valve body 33) generated by the movement of the valve body 33 from the seal surface 32 at the time of engine low load is about 20 microns. If the width of the fuel injection passage 35 (the cross-sectional height / gap size between the nozzle body 30 and the valve body 33) gradually increases on the downstream side of the seal surface 32, the combustion chamber of the fuel injection passage 35 Even if the opening on the side is not completely closed, the shielding wall 51 is brought close to the valve body 33 so as to cover the opening, and for example, the clearance of the opening on the combustion chamber side of the fuel injection passage 35 is set to about 20 microns. In this case, fuel injection from the opening on the combustion chamber side of the fuel injection passage 35 can be prevented. Even if the width of the fuel injection passage 35 (the cross-sectional height / gap size between the nozzle body 30 and the valve body 33) is substantially constant on the downstream side of the seal surface 32, the combustion of the fuel injection passage 35 is also performed. By bringing the shielding wall 51 close to the valve body 33 so as to cover the opening on the chamber side, fuel injection can be prevented even if the opening is not completely closed.

  In the third embodiment, the fuel is injected from the fuel injection port 31 toward the ridge line 12 at the compression top dead center when the engine is under a low load. The fuel injection valve in the third embodiment Also in 19, the fuel spray injected at this time is formed so as not to contact the upper inner wall surface 7 and does not adhere to the inner wall surface of the combustion chamber 6.

  In such a third embodiment, fuel is not injected from the fuel injection port 31 toward the intake side inclined surface 9 and the exhaust side inclined surface 11 at the time of engine low load with a small amount of fuel injection. When the engine quantity is low and the fuel spray is not in contact with the upper inner wall surface 7 of the pent roof type combustion chamber 6 from the fuel injection valve 19, it does not rebound to the output of the internal combustion engine, reduces unburned loss, and reduces fuel consumption. Can be improved.

  Further, when the engine is under a heavy load with a large amount of fuel injection, fuel is injected from the entire circumference of the fuel injection port 31, and the substantial opening area of the fuel injection valve 19 is maximized. By suppressing the injection valve 19 opening time) and ensuring the fuel spray mixing time, homogeneous combustion can be carried out stably.

  The fuel injection valve 19 in each of the above-described embodiments is a so-called piezo-type fuel injection valve, and a piezo element is used as a drive actuator for the valve element 33, but a solenoid is used as a drive actuator. It is applicable also to an injection valve.

  In the first and second embodiments described above, the notch 36 is provided in the nozzle body 30, so that the passage length L <b> 1 of the fuel injection passage 35 at a position where fuel is injected from the fuel injection port 31 along the ridge line 12. Is shorter than the passage length L2 of the fuel injection passage 35 at a position where fuel is injected from the fuel injection port 35 toward the intake side inclined surface 9 and the exhaust side inclined surface 11. By appropriately setting the shapes of the tip of the nozzle body 30, the fuel injection port 31, and the valve body 33 to be circular or elliptical so that the length of the fuel injection passage 35 changes in the circumferential direction, a notch 36 is provided. The passage length L1 of the fuel injection passage 35 at a position where fuel is injected from the fuel injection port 31 along the ridgeline 12 is determined from the fuel injection port 31 to the intake side inclined surface 9 and the exhaust side inclined surface. It is also possible to be shorter than the path length L2 of the fuel injection passage 35 at a position for injecting fuel toward 1.

DESCRIPTION OF SYMBOLS 1 ... Cylinder block 2 ... Cylinder 3 ... Cylinder head 6 ... Combustion chamber 7 ... Upper inner wall surface 9 ... Intake side inclined surface 11 ... Exhaust side inclined surface 12 ... Ridge line 19 ... Fuel injection valve 30 ... Nozzle body 31 ... Fuel injection port 32 ... Seal surface 33 ... Valve element 34 ... Guide part 35 ... Fuel injection passage 36 ... Notch part 37 ... Overhang part

Claims (9)

An intake side inclined surface where an intake port opens, an exhaust side inclined surface where an exhaust port opens, an intake side inclined surface and the exhaust side inclined surface are abutted each other, located above a cylinder provided in the cylinder block. A pent roof type combustion chamber composed of an upper inner wall surface of a cylinder head having a linear ridge line formed in the portion;
A nozzle body disposed on the ridgeline and formed with a fuel injection port, a tapered seal surface formed on the outer periphery of the fuel injection port, and closing the fuel injection port by seating on the seal surface An externally-open fuel injection valve that injects fuel into a hollow conical shape in the combustion chamber. In the institution
The fuel injection valve injects the fuel spray injected along the ridge line toward the intake-side inclined surface and the exhaust-side inclined surface as compared with an angle formed by an outer line on the upper inner wall surface side and a cylinder axis. An internal combustion engine characterized in that the angle formed by the outer axis of the upper inner wall surface of the fuel spray and the cylinder axis is reduced. The fuel injection valve has a guide portion that guides fuel injected from the fuel injection port toward the combustion chamber when the valve body is separated from the seal surface,
The guide portion is formed in a shape different from each other between a position where fuel is injected along the ridgeline and a position where fuel is injected toward the intake side inclined surface and the exhaust side inclined surface. The internal combustion engine according to claim 1. The guide portion has a fuel injection passage sandwiched between the nozzle body and the valve body,
Compared to the fuel injection passage at a position where fuel is injected from the fuel injection port along the ridgeline, the fuel injection port is configured to inject fuel from the fuel injection port toward the intake side inclined surface and the exhaust side inclined surface. The internal combustion engine according to claim 2, wherein the fuel injection passage is formed to be long. The nozzle body and the valve body are circular around the axis of the fuel injection valve passing through the fuel injection port,
The internal combustion engine according to claim 3, wherein at least one of the nozzle body and the valve body is cut out at a position where fuel is injected from the fuel injection port along the ridgeline.   The fuel injection valve has an intake side inclined surface and an exhaust side inclined from the fuel injection port as compared to a spray angle viewed from a direction perpendicular to a cylinder axis of fuel spray injected along the ridge line from the fuel injection port. The internal combustion engine according to any one of claims 1 to 4, wherein a spray angle as viewed from a direction perpendicular to a cylinder axis of fuel spray injected toward the surface is reduced.   The guide portion is sandwiched between the nozzle body and the valve body, and extends from the fuel injection port to the intake side inclined surface and the exhaust side inclined surface. The internal combustion engine according to claim 2, further comprising a shielding wall capable of preventing fuel spray from the fuel injection passage to the combustion chamber at a position where fuel is injected.   The shielding wall is directed from the fuel injection port toward the intake side inclined surface and the exhaust side inclined surface in the amount of movement of the valve body from the seal surface when injecting the fuel injection amount at the time of engine low load. The amount of movement of the valve body from the seal surface when the fuel is injected from the fuel injection passage to the combustion chamber at the fuel injection position and the fuel injection amount at the time of high engine load is injected The fuel injection from the fuel injection passage to the combustion chamber is allowed at a position at which fuel is injected from the intake side toward the intake side inclined surface and the exhaust side inclined surface. Internal combustion engine.   When the fuel injection valve injects fuel, if the amount of movement of the valve body from the seal surface is small, a stratified mixture is formed in the combustion chamber at a timing near top dead center, and compression self-ignition is performed. The internal combustion engine according to any one of claims 1 to 7, wherein the stratified mixture in the combustion chamber is combusted. By controlling the amount of movement of the valve body from the seal surface, the fuel injection amount injected from the fuel injection valve and the mixture distribution in the combustion chamber are controlled,
When the engine is under a low load, the amount of movement of the valve element from the seal surface is controlled to be smaller than when the engine is under a high load, and a stratified mixture is formed in the combustion chamber at a timing near the top dead center. The internal combustion engine according to any one of claims 1 to 8, wherein

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