JPH09256936A - Direct-injection ignition type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide stable combustion during a low load period, to reduce emission of exhaust gas (THC), and to improve fuel consumption at the time of a low load. SOLUTION: In a direct-injection ignition type internal combustion engine in which a fuel is directly injected from an injector 61 arranged on a wall of a combustion chamber 29 into the combustion chamber 29 formed by a cylinder head 23, a cylinder body 22 and a piston 26 and ignited by an ignition plug 30 provided at the cylinder head 23, the fuel is injected at least divided into twice at the time of low speed and/or low load, and the fuel injected at the latest timing is ignited by the timing passing near the ignition plug.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-cycle or four-cycle direct injection ignition type internal combustion engine in which fuel is directly injected into a cylinder and a spark plug is ignited and ignited.

[0002]

2. Description of the Related Art In a fuel injection type internal combustion engine, for example, a combustion chamber is formed by a cylinder head, a cylinder body and a piston, an ignition plug is attached to the cylinder head, an injector is attached to a cylinder side wall, and the combustion chamber is introduced from the injector. Some inject fuel. For example, there is a two-cycle ignition type engine disclosed in Japanese Patent Publication No. 6-508670, in which an injector is arranged on a side wall of a cylinder. In this engine, an injector is arranged on a side wall of a cylinder facing an exhaust port, and a piston is arranged. Fuel is being injected in the direction.

Since this fuel injection is so-called premixed combustion in which a uniform combustible mixture is ignited in the combustion chamber so as to obtain a sufficient output particularly at high speed and high load, it is carried out sufficiently before the ignition timing.

[0004]

However, when the fuel is injected early at the time of low load and premixed combustion is performed to ensure that the fuel is oxidized to CO ₂ and H ₂ O, the atomization will occur. It spreads and the ignitability deteriorates. Further, if the fuel is retarded and injected, the ignitability is improved because there is a thick spray around the spark plug, but the exhaust gas (THC) may be discharged in a large amount due to insufficient mixing with air.

Further, in a two-cycle engine, gas exchange by sweeping exhaust cannot be sufficiently performed at low speed and / or low load, and exhaust gas generated in the previous combustion cycle is mixed into fresh air in the combustion chamber before ignition. (So-called EG
R may increase), ignitability may decrease, and misfire may occur. Due to this misfire, the fuel injected is directly or incompletely burned in the exhaust passage and discharged into the atmosphere.

The present invention has been made in view of the above point, and has the stability of combustion in a low load period and exhaust gas (TH).
It is an object of the present invention to provide a direct injection ignition type internal combustion engine which can reduce the emission amount of C) and further improve fuel efficiency at low load.

[0007]

In order to solve the above-mentioned problems and to achieve the object, the invention according to claim 1 provides a combustion chamber formed by a cylinder head, a cylinder body and a piston. In a direct injection ignition type internal combustion engine in which fuel is directly injected from an injector arranged on a wall, and ignition is ignited by an ignition plug provided in a cylinder head, at least twice at low speed and / or low load. It is characterized in that the fuel is injected at the latest timing and the fuel injected at the latest timing is ignited at the timing while passing near the spark plug.

[0008] At low load with a small amount of air-fuel mixture per combustion cycle and / or at low speed with a large amount of EGR, the ignitability deteriorates, but at the time of ignition, the injected fuel passes near the spark plug and the ignitability is improves. Moreover, the fuel injected prior to the fuel injection at the latest timing to improve ignitability forms a uniform air-fuel mixture in the combustion chamber, which increases combustion stability, which improves output and improves fuel efficiency. As a result, the emission amount of HC, CO or NOx in the exhaust gas can be reduced.

Particularly in a two-cycle engine, gas exchangeability is poor, and EGR increases, and in a four-cycle engine, exhaust gas flows backward from the intake valve due to opening of the intake valve before closing of the exhaust valve.
The increase in GR hinders the stability of combustion and also the ignitability, but this defect can be complemented, and reliable ignition and stable combustion can be realized.

The invention according to claim 2 is a cylinder head,
A direct injection ignition type internal combustion engine in which at least two injectors are arranged on a wall of a combustion chamber formed by a cylinder body and a piston, and ignition is ignited by an ignition plug provided on a cylinder head after fuel injection from the injectors is completed. In the above, at low speed and / or low load, the injection timing of at least two injectors is moved forward and backward, and the fuel from the injector that is injected at the latest timing is injected toward the vicinity of the spark plug. .

By forming a more uniform mixture in the combustion chamber at low speed or low load, and by directing the fuel injected at a later timing toward the ignition plug even when it is not passing near the ignition plug at the time of ignition, Stable combustion can be realized by making it possible to perform firing close to stratified combustion. Further, since a plurality of injectors are arranged, it is possible to make the injector small when the total injection amount is set to a predetermined amount, or it is possible to reduce the injection pressure. Further, since the injection at the later timing can surely direct the spark plug, more stable combustion is possible. If the fuel injected at a late timing is passing near the ignition plug at the time of ignition, the ignitability is further improved.

The invention according to claim 3 is a cylinder head,
An injector having a plurality of injection holes for generating fuel injection flows directed in a plurality of directions is arranged on a combustion chamber wall formed by a cylinder body and a piston, and is provided on a cylinder head after fuel injection from the injector is completed. In a direct injection ignition type internal combustion engine in which ignition is ignited by a spark plug, one fuel injection flow is directed near the spark plug.

Since the fuel injection for the combustion cycle is divided into a plurality of injections, the fuel injection for the combustion cycle is divided into a plurality of injections.
The amount of GR can be reduced (in both 2-stroke and 4-stroke engines). Therefore, it is possible to improve the ignitability due to the decrease in EGR and to realize stable combustion. Also, because of intermittent injection,
A larger amount of injection is required per injection than when fuel is injected and ignited and burned at each crankshaft rotation, but in the combustion cycle, the timing when the compression ratio in the combustion chamber is low due to the multiple injections. Fuel will be injected at
Since the pressure difference from the injection pressure becomes large, a large amount of fuel can be injected, and a uniform air-fuel mixture is formed in the combustion chamber. Even if the fuel injected at a late timing does not pass through the vicinity of the spark plug at the time of ignition, by directing to the spark plug, combustion close to stratified combustion can be performed, and stable combustion can be realized. If the fuel injected at a late timing is passing near the ignition plug at the time of ignition, the ignitability is further improved.

According to a fourth aspect of the present invention, the fuel is injected intermittently during one revolution per multiple revolutions of the crankshaft at low speed and / or low load, and the fuel is injected into the combustion chamber at least twice. It is characterized by doing so. At low speed and / or low load, a more uniform air-fuel mixture is formed in the combustion chamber, and the fuel injected at a later timing does not pass near the ignition plug at the ignition point,
By directing the spark plug, it becomes possible to perform combustion close to stratified combustion, and since it is one injector, stable combustion can be realized at low cost.

The invention according to claim 5 has a plurality of cylinders,
It is characterized in that intermittent injection is performed in which fuel is injected during one revolution per a plurality of crankshaft revolutions in at least one cylinder at low speed and / or low load. Even in a plurality of cylinders, stable combustion can be realized by intermittent injection.

The invention according to claim 6 has a plurality of cylinders,
The feature is that intermittent injection is sequentially performed in all cylinders at low speed and / or low load. The heat load can be made uniform by performing intermittent injection in all cylinders in sequence. Further, when a phase difference is provided in a plurality of cylinders, torque fluctuations in intermittent injection can be reduced.

According to a seventh aspect of the present invention, the fuel is injected twice at low speed and / or low load, and
The injection amount of the first injection injected at an early timing is q1, and the injection amount of the second injection injected at a late timing is q2.
In this case, the injection amount q1 is larger than the injection amount q2. Since the concentration of the homogeneous mixture can be increased, more stable combustion can be achieved.

The invention according to claim 8 is characterized in that the injected fuel is ignited at a timing when the injected fuel has completed passing through the vicinity of the spark plug, at least at a high speed and a high load. Since more reliable premixed combustion can be performed at high speed and high load, the combustion speed can be increased to match the high engine speed.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the direct injection ignition type internal combustion engine of the present invention will be described below. 1 to 6 show an embodiment in which a direct injection ignition type internal combustion engine is mounted on an outboard motor, and FIG. 1 mainly shows one cylinder of the embodiment in which a direct injection ignition type internal combustion engine is mounted on an outboard motor. FIG. 2 is a schematic configuration diagram, FIG. 2 is a flowchart of fuel and air for cylinder side wall injection, and FIG. 3 is a vertical cross-sectional view of an upper portion of one cylinder of a direct injection ignition type internal combustion engine.
FIG. 4 is a cross sectional view of the direct injection ignition type internal combustion engine, FIG. 5 is a cross sectional view showing an exhaust system, and FIG. 6 is a plan view of the direct injection ignition type internal combustion engine.

In FIG. 1, reference numeral 1 indicates a ship which is a vehicle, and an arrow Fr indicates the forward direction of the ship 1. In addition, the left and right described below means the direction toward the front. The ship 1 has a hull 2, and an outboard motor 3 is detachably attached to the stern of the hull 2. The outboard motor 3 is composed of a bracket 4 attached to the stern and an outboard motor body 6 pivotally supported by a pivot shaft 5 (arranged horizontally at right angles to the Fr direction) with respect to the bracket 4. There is. The outboard motor body 6 includes a power transmission device 8, and the power transmission device 8 includes a transmission case 9 that forms an outer shell of the power transmission device 8 and a transmission mechanism that is housed in the transmission case 9.
With respect to a swivel bracket 6a that constitutes an outboard motor body 6 that is pivotally supported by a pivot shaft 5 with respect to the bracket 4, a transmission that is swingable in the left-right direction by a pivot shaft (not shown) that is arranged in a substantially vertical direction. Case 9 is pivotally supported. Further, the outboard motor main body 6 has a two-cycle engine 10 which is a fuel injection type internal combustion engine. The engine 10 is detachably attached to the upper end of the transmission case 9, and the lower portion is covered with a cover 11a.
The upper part is covered with a cover 11b so as to be openable and closable. The transmission case 9 extends downward into the water, and a shaft (not shown) extending rearward is supported at the lower end of the transmission case 9, and a propeller 14 is attached to the shaft. The propeller 14 is connected to the output portion of the engine 10 via the transmission mechanism of the power transmission device 8 so as to interlock with each other. In addition, 13 is an exhaust passage for guiding the exhaust to the propeller.

The engine 10 is provided with a plurality of (three) cylinders including a first cylinder 16, a second cylinder 17, and a third cylinder 18,
These are stacked one above the other. Engine 10
A common crankcase 19 and a cylinder body 22 are provided for each of the cylinders 16 to 18, and a vertically oriented crankshaft 20 having a substantially vertical axis is accommodated in a joint portion between the crankcase 19 and the cylinder body 22. The shaft 20 is supported by the crankcase 19 and the cylinder body 22 so as to be rotatable around their axes. Crankcase 1
The cylinder body 22 of each of the cylinders 16 to 18 is integrally attached to the rear portion of the cylinder 9. Further, the cylinder head 23 is attached to the protruding end of each of the cylinder bodies 22.
Is detachably attached. Cylinder body 22
They are integrated with each other to form a cylinder block 24, and the cylinder heads 23 are also integrated with each other.

Each cylinder body 22 has a cylinder hole 25 inside of which extends axially in parallel with each other in the front-rear direction, and a piston 26 is slidably fitted in the front-rear direction in the cylinder hole 25. Each of these pistons 26
Each of them is connected to the crankshaft 20 by a connecting rod 27. The space surrounded by the cylinder head 23 and the piston 26 in the cylinder hole 25 corresponds to the “in-cylinder”, and the “in-cylinder” in which the piston 26 is close to the cylinder head 23 to some extent serves as the combustion chamber 29. Cylinder head 2
3 includes one spark plug 3 corresponding to each combustion chamber 29.
0 is attached, and the discharge unit 3 of each of these spark plugs 30 is attached.
1 faces the combustion chamber 29. The cylinder block 24 and the crankcase 19 are provided for each cylinder in the crank chamber 19a.
Is formed.

Three intake ports 33, which communicate with the crank chambers 19a, are formed on the front surface of the crankcase 19, and the reed valves 34 are provided in the intake ports 33, respectively.
Is attached. Further, on the front surface of these reed valves 34, an intake manifold 35, a throttle body 36 accommodating a throttle valve 36a, and an intake silencer 3 are provided.
7 are arranged in sequence. Further, an inlet pipe 38 opening rearward is attached to the upper end of the intake silencer 37, and the outside air is sucked from the cowling opening 510. Inlet pipe 38, intake silencer 37, throttle body 3
6, the intake manifold 35 and the reed valve 34 are communicated with each other by the intake passages 39 provided inside thereof, and the intake passages 39 are communicated with the intake port 33. Each throttle body 36
The throttle levers 36b provided in the above are connected to each other by the interlocking means 40, and when the operator operates the operation part, the throttle levers 36b and the throttle valve 36a are synchronized with each other through the interlocking means 40 to perform the same opening / closing operation. It is like this.

In the cylinder body 22 around each cylinder hole 25, a scavenging passage 41 is formed for each cylinder hole 25. The scavenging passage 41 has the cylinder hole 2
The two main scavenging passages 41a having the scavenging port 41a1 opening to 5 and one auxiliary scavenging passage 41b having the scavenging port 41b1 are formed, and the scavenging ports 41a1 of the main scavenging passage 41a are formed at opposite positions, Sub-scavenging passage 4
The scavenging port 41b1 of 1b is formed at a position facing the exhaust port 44. Each of these scavenging passages 41 communicates the inside of the crankcase 19 with the combustion chamber 29.

An exhaust manifold 42 is attached to the left side of the cylinder block 24.
One end side of the first exhaust passage 43 in 2 is branched into a plurality (three), and the exhaust port 44 formed in each cylinder body 22.
It opens to each combustion chamber 29 through. On the other hand, the exhaust guide 46 is provided between the cylinder block 24 and the transmission case 9.
And a second exhaust passage 47 in the exhaust guide 46.
And the other end side of the first exhaust passage 43 are communicated with each other. A third exhaust passage 48 is formed in the transmission case 9, one end of the third exhaust passage 48 communicates with the second exhaust passage 47, and the other end is a cylindrical exhaust passage 13, which is an exhaust passage in the propeller 14. And an end portion of this exhaust passage is opened in the water as a discharge port 506.

The engine 10 has a water-cooling type cooling device 50.
Is provided. The cooling device 50 includes a first cooling water jacket 51 formed in the cylinder head 23 and the cylinder block 24, a second cooling water jacket 52 formed in the exhaust manifold 42, and an exhaust gas so as to surround the second exhaust passage 47. The transmission case 9 surrounds the third cooling water jacket 53 formed in the guide 46 and the third exhaust passage 48.
And a fourth cooling water jacket 54 formed in the above. The cooling water jackets 51 to 54 are in communication with each other directly or through a plurality of cooling water communication passages 55.
The lower end of the fourth cooling water jacket 54 communicates with the downstream side of the third exhaust passage 48.

A water pump for supplying cooling water 56 such as seawater to the first cooling water jacket 51 is provided, and the cooling water 5
Reference numeral 6 denotes an exhaust manifold outer peripheral portion 51a in the first cooling water jacket 51, a second cooling water jacket 52, a cylinder upper outer peripheral portion 51b in the first cooling water jacket 51, the cylinder head portion 51c, and 53, 54. Each cooling water jacket is sequentially passed through, and the water is drained into the water through the downstream end of the third exhaust passage 48.
-The 3rd cylinder 16-18 is cooled.

The engine 10 is provided with a fuel supply device 60 for supplying fuel 59. The fuel supply device 60 has a plurality of (three) injectors 61 corresponding to the first to third cylinders 16 to 18, and each injector 61 is detachably attached to the cylinder side wall 22 a of the cylinder body 22. The injectors 61 are arranged so that the fuel 59 is appropriately introduced from the cylinder side wall 22a into the combustion chamber 29.
Inject. Each injector 61 sucks the fuel 59 stored in the fuel tank 63 arranged in the hull 2 and supplies it to the vapor separator 67, which is a fuel pool (small tank) in the outboard motor 3, inside the crank chamber 19a. The first fuel pump 64 that operates due to fluctuations, and the second fuel pump 6 that pressurizes and supplies the fuel 59 of the vapor separator 67.
And 5 are provided in series.

A primary pump 600 is arranged between the fuel tank 63 and the first fuel pump 64, and the primary pump 600 and the first fuel pump 64 are connected to the hose side connector 6
01 and the cowling side connector 602.
The primary pump 600 is for manually feeding fuel before starting.

A fuel filter 66 and a vapor separator 67 are provided in series between the first fuel pump 64 and the second fuel pump 65. Vapor separator 6
7 is provided with a needle valve 603 and a float 604, and when the fuel 59 in the vapor separator 67 is low and the float 604 is below a predetermined level, the needle valve 6
03 is opened, and the fuel 59 is supplied from the fuel tank 63 side. The fuel 59 is supplied to each injector 61 via the fuel delivery pipe 605 by the second fuel pump 65. The fuel delivery pipe 605 has a fuel 59 supplied to the injector 61.
A pressure regulator 69 that adjusts the pressure of the second fuel pump 65 to a predetermined pressure is provided.
It is returned to the upstream vapor separator 67. The vapor separator 67 separates fine bubble-like fuel vapor or mixed air in the fuel.

Each injector 61 is an electromagnetic type, and when it is electrically turned on (or off), the fuel 59 is injected into the combustion chamber 29 only during that period.
Of this fuel supply device 60, only the hose side connector 601 from the fuel tank 63 is arranged inside the hull 2, and the other components constitute the outboard motor 3.

In FIG. 1, an engine control device 73 for controlling the engine 10 is provided. The engine control device 73 includes an electronic control device body 74, and each spark plug 30, which functions as an actuator, the injector 61, and the second fuel pump 65 are electrically connected to the control device body 74. A flywheel magnet 75 is attached to the upper end of the crankshaft 20. The flywheel magneto 75 supplies power to the control device body 74 directly or via a battery.

Various sensors for detecting the driving state of the engine 10 are provided, and all of these are electrically connected to the controller main body 74. That is, as a sensor, a crank angle sensor 76 for detecting a reference crank angle and a rotation angle of the crank shaft 20, a crank case internal pressure sensor 77 for detecting a pressure in the crank case 19, and a pressure of any one of the cylinders 16-18. In-cylinder pressure sensor 78, a knock sensor 79 that detects the state of the cylinders 16 to 18, an intake temperature sensor 80 that detects the temperature in the intake passage 39, and a throttle opening sensor 81 that detects the opening of the throttle body 36. Is provided. An intake pressure sensor that detects the pressure in the intake passage 39 may be provided.

A cylinder temperature sensor 82 for detecting the temperature of one cylinder body 22, a back pressure sensor 83 for detecting the upstream pressure in the third exhaust passage 48, an atmospheric pressure sensor 84 for detecting the atmospheric pressure, and a cooling. Cooling water temperature sensor 85 for detecting the temperature of water 56, forward movement of power transmission device 8, neutral,
A shift sensor 86 for detecting a shift operation or a gear shift state during reverse movement, and a trim angle sensor 87 for detecting a vertical rotation position of the outboard motor 3 around the pivot 5 are provided.

Further, each cylinder 16-18, O ₂ sensor 90 is provided, the O ₂ sensor 90 is a sensor Osamu Room 9
1, the piston 26 descends and the cylinder side wall 22
When passing through the relief valve hole 92 of a, the relief valve 93 is opened by the combustion gas pressure, and the combustion gas enters the sensor collection room 91. The O ₂ sensor 90 detects the O ₂ concentration in the exhaust gas and calculates the air-fuel ratio in the combustion chamber 29 based on this. The exhaust gas in the sensor housing chamber 91 passes through the check valve 94 and exits into the first exhaust passage 43. The engine 10 also includes a starter 9
5 and an oil tank 96 are provided.

When the piston 26 moves from the bottom dead center position on the crankshaft 20 side to the combustion chamber 29 side in sequence in each of the first to third cylinders 16 to 18 when the engine 10 is driven, the scavenging passage 41 is formed by the piston 26. Scavenging ports 41a1, 41b1 and the exhaust port 4 of the first exhaust passage 43
4 and 6 are sequentially closed. Also, like this, the piston 2
When 6 moves to the combustion chamber 29 side, the crank chamber 19a in the crankcase 19 becomes negative pressure. Then, the reed valve 3
4, intake passage 39 in intake port 33, intake manifold 35, throttle body 36, and intake silencer 37
Gradually becomes negative pressure, and the outside air 97 as air is sucked into the intake passage 39 from the intake port 33, and the crankcase 19
It is sucked into the internal crank chamber 19a. This is the "suction stroke".

On the other hand, the scavenging port 41a of the scavenging passage 41
If the piston 26 further moves to the combustion chamber 29 side after the 1, 41b1 and the exhaust port 44 of the first exhaust passage 43 are closed, the air-fuel mixture that has already been sucked into the combustion chamber 29 is compressed. . This is the "compression stroke". The "suction stroke" is performed simultaneously during the "compression stroke".

Immediately before the piston 26 reaches the top dead center, the discharge of the discharge portion 31 of the spark plug 30 controlled by the engine control device 73 ignites and combusts the air-fuel mixture to expand the gas. After the piston 26 exceeds the top dead center, it is pushed back to the crankshaft 20 side. This is the “explosion process”.

The movement of the piston 26 toward the crankshaft 20 pre-compresses the air sucked into the crank chamber 19a in the crankcase 19. The reed valve 34 is closed by the pressure at this time. Piston 26
The exhaust port 44 is first opened while the vehicle moves toward the crankshaft 20. Then, the exhaust 100, which is the burned gas of the air-fuel mixture, is discharged through the exhaust port 44 through the exhaust port 44. This is the "exhaust stroke".

Then, the exhaust 100 is the first exhaust passage 43,
It is discharged into the water through the second exhaust passage 47, the third exhaust passage 48, and the exhaust passage 13 sequentially. In this case, the cooling water 56 after cooling the cylinders 16 to 18 passes through the fourth cooling water jacket 54 and the cooling water communication passage 55, and is discharged into the water together with the exhaust 100.

When the piston 26 moves to the crankshaft 20 side and the exhaust port 44 is opened, the scavenging passage 41 is subsequently opened. Then, as described above, the intake air that has been pre-compressed in the crankcase 19 is caused to flow into the combustion chamber 29 through the scavenging passage 41, and this intake air partially removes the burned gas remaining in the combustion chamber 29. The combustion chamber 29 is filled with air while being pushed out into the first exhaust passage 43. This is the “scavenging stroke”. Since the scavenging stroke starts in the middle of the exhaust stroke, and the exhaust stroke ends in the middle of the scavenging stroke, this 2
The two strokes are collectively referred to as the sweep stroke. Then, after this, the piston 26 returns to the bottom dead center position. Then, the fuel is injected from the injector 61 during the period from the middle of the sweeping exhaust stroke to the beginning of the compression stroke.

In this case, the combustion chamber 2 passes through the scavenging passage 41.
Some of the air that has flowed into 9 is blown to the side of the first exhaust passage 43, which is mixed with the burnt gas and is exhausted as the exhaust 100. On the other hand, the burnt gas remaining without being discharged is mixed with the fresh air, and in this state, the piston 26 again moves to the combustion chamber 29.
After that, the crankshaft 20 is rotated by repeating the above steps. It should be noted that the fuel injection is performed at a timing when fuel does not enter the exhaust port 44, as described below. Then, the engine 10 outputs power through the crankshaft 20, and this power causes the propeller 14 to rotate via the power transmission device 8 to allow the ship 1 as a driven body to travel. First cylinder 16, second cylinder 1
7 and the third cylinder 18 have a crank angle of 1 in this order.
Drive with a phase difference of 20 °.

In FIG. 3, the piston 26 is the sleeve 5
20 is slidably provided on the piston 26, and the piston 26 has a first
Ring groove 26a and second ring groove 26b are formed vertically, and the first piston ring 521 is engaged with the first ring groove 26a and the second piston ring 522 is engaged with the second ring groove 26b. There is. An injector 61 is provided on the cylinder side wall 22a via a cap 523, and the front side and the rear side of the cap 523 are respectively seal bodies 524 and
It is sealed at 525. A tip portion 61a of the injector 61 is formed on the sleeve 520 and arranged so as to face the opening 520a, and the mounting position of the injector 61 is set as follows.

When the distance from the cylinder upper end 22b to the mounting position is A and the distance from the cylinder upper end 22b to the piston top outer circumference when the piston 26 is located at the bottom dead center is L, at least 1 is set on the outer circumference of the piston. When a ring groove for fitting two piston rings is provided and the distance from the cylinder upper end 22b to the lower end position of the ring groove when the piston 26 is at the top dead center is RS, in this embodiment, the piston 26 is top dead. The first ring groove 2 into which the first piston ring 521 is fitted from the cylinder upper end 22b when the point is at the point
When the distance to the lower end position of 6a is RS, RS <A <0.3L.

When ES is the distance from the cylinder upper end 22b to the exhaust port 44, 0.35ES <A <0.65ES.

In this way, the injector 6 is placed at the predetermined position.
By attaching 1, while reducing the heat load on the injector by the piston 26 at the beginning of the explosion stroke,
In addition, it is possible to secure a longer jettable range than the conventional one.

Further, fuel is injected from the injector 61, and the injection flow X is injected mainly toward the piston top portion 26c which is rising from the bottom dead center of the piston 26 to the top dead center. The injection flow X cools the piston top portion 26c, and the fuel itself is promoted to be vaporized.

Then, the injector 61 injects fuel once at a time when it does not blow through during one combustion cycle when the load is medium and high. Since the heat and the air flow in the combustion chamber 29 are large at the time of this medium and high load, by appropriately injecting once at a time when the air does not blow through, an appropriate fuel is supplied and fuel efficiency is improved.

On the other hand, at low load and / or low speed,
Intermittent injection is performed from the injector 61 during one rotation of the crankshaft 20 rotating a plurality of times. In the multiple injections of the crankshaft 20, the first injection is set to an early timing that satisfies the condition that the spray does not escape, and the second injection is late so that the fuel at the end of injection does not fall on the side wall of the piston. Depending on the timing, the second injection is injected toward the recess 26d formed in the head 26c of the piston 26.

The fuel of the first injection is reflected by the piston 26,
Since the exhaust port 44 is closed by the piston 26 just before reaching the exhaust port 44, there is no fuel blow-through.
Further, when reflected by the piston 26, the injection flow spreads while exchanging heat with the piston 26, and therefore spreads over the entire combustion chamber 29 and is vaporized, forming a mixture in a wide range of the combustion chamber 29. However, when the injection amount of the first injection is q1 and the injection amount of the second injection is q2, q1 itself is a part of the injection fuel family, and the air-fuel mixture is in a lean state. The second injection is performed after a predetermined time has elapsed from the end of the first injection. This second injection is slow, and is performed just before the piston 26 covers the injector 61. Therefore, the second injection is performed by the head 26 of the piston 26.
The fuel is injected toward the recess 26d formed in c, and the direction of the fuel is changed when the fuel hits the recess 26d.
Head around 0.

A spark current flows through the ignition plug 30 while the fuel injection flow directed toward the ignition plug 30 passes through the ignition portion itself of the ignition plug 30 or in the vicinity thereof, and a rich concentration is formed in the ignition portion during the passage of the fuel injection flow. The air-fuel mixture ignites and combustion begins.

In this way, since the thick spray is present around the spark plug 30, the ignitability is improved, and in the space distant from the spark plug, the mixture with air is sufficiently diluted but combustion stability and exhaust gas ( THC) emissions can be reduced, and fuel efficiency at low load is improved. In addition,
Since the injection is performed intermittently, the total injection amount at the time of injection becomes larger than that in the case of injection every time. Therefore, particularly in the case of a four-cycle engine, the throttle opening is made slightly larger than the opening at which intermittent injection is not performed.

The injection quantity q1 of the first injection is larger than the injection quantity q2 of the second injection, and when the load is low, the injection quantity q1 of the first injection is changed to the injection quantity q2 of the second injection during one combustion cycle. By making the injection quantity q2 larger and injecting twice, the fuel is injected substantially evenly into the entire combustion chamber to improve the ignitability, and the mixing with the air is sufficient to ensure the stability of combustion and the exhaust gas (THC). ) Emissions can be reduced, and fuel economy at low load is further improved.

The injector 61 is a sub-scavenging port 41b1.
It is arranged closer to the cylinder head 23, and the injection flow X is directed toward the exhaust port 44 and toward the piston top portion 26c. After the exhaust port 44 is closed by the piston 26, it reliably hits the piston top portion 26c and the piston top portion 26c.
Is heat exchanged.

The injection start timing is set so that the exhaust port 44 is closed before the tip of the injection flow X reaches the exhaust port 44. The front end surface of the jet flow X is indicated by X1. In the case where all of the injection flow X hits the piston top portion 26c before the piston 26 closes the exhaust port 44, the exhaust port 44 closes before the tip of the injection flow after rebounding reaches the exhaust port 44, and thus injection is performed. The start timing is set.

As described above, the injector 61 is arranged as follows.
The injection position is closer to the cylinder head 23 than in the prior art, and the injection flies a longer distance. During this time, the fuel exchanges heat with the thermal atmosphere in the combustion chamber 29 and the piston top 2
Heat can be exchanged even before it collides with 6c or the like.

Further, in FIG. 4, the fuel distribution pipe 530 to the injector 61 is parallel to the plane connecting the central axes of the plurality of cylinders, and the injector 61 is arranged at the same position in all the three cylinders 16-18. ing.

Alternatively, the lower cylinder may have the injector 61 arranged lower (closer to the crank chamber). The lower the cylinder, the larger the thermal load on the injector 61, so that the piston 26 is covered for a long time in the combustion stroke.
On the other hand, at least the uppermost cylinder 16 has the injector 61
Position of RS <A <0.3L and 0.35E
S <A <0.65 ES.

Further, the direction connecting the auxiliary scavenging port 41b1 and the exhaust port 44 is inclined, and the injector 61 is also inclined, so that the cylinder pitch P can be narrowed while avoiding the interference of the main scavenging ports 41a1 of the adjacent cylinders.

Next, the structure of the injector of the fuel injection device used in the embodiment shown in FIGS. 1 to 6 will be described. Figure 7
Is a sectional view of the injector, FIG. 8 is a sectional view of the tip of the injector, and FIG. 9 is a front view of the nozzle of the injector.

The injector 61 has an injector housing 350, a lid 351 is fitted to the rear end portion of the injector housing 350, and a core 35 having a coil 352 inside the injector housing 350.
3 are arranged. The lid 351 is a resin cap 3
The connector 354a of the cap 354 is provided with a lead wire 355 connected to the core 353, and the lead wire 355 is connected to the drive power source side by the connector 354a. The pipe 356 is inserted into the lid body 351 and
The fuel supplied from the fuel inlet 351a of 51 is introduced into the fuel chamber 357 in the injector housing 350 via the pipe 356.

A needle housing 358 is fitted into the tip end portion of the injector housing 350 via a needle stopper 359, and is sealed by a seal body 360.
A nozzle 361 is fitted at the tip of the needle housing 358, an injection passage 361a is formed in the nozzle 361, and a downward injection hole 361c is formed in communication with the injection passage 361a. The diameter D2 of the downward injection hole 361c is smaller than the diameter D0 of the injection passage 361a.

A needle 362 is movably arranged in the needle housing 358, and a movable body 363 is fixed to the needle 362. A fuel passage 362a is formed in the needle 362 by notching, and the needle stopper 3
A fuel passage 359a is formed in the notch 59 by a notch, and a fuel passage 363a is also formed in the movable body 363. A compression spring 364 is disposed between the lid 351 and the movable body 363. The compression spring 364 urges the needle 362 through the movable body 363 in a direction in which the valve seat 358a of the needle housing 358 is always closed. 36
1a is closed and the fuel cannot be injected. Core 3
When power is supplied to the coil 352 disposed at the position 53, the movable body 363 is attracted by the electromagnetic force of the coil 352 against the compression spring 364 and moves in the direction to open the valve seat, thereby opening the injection passage 361a and fuel injection. Is performed. At this time, the stopper flange 362b formed on the needle 362
Abuts on the needle stopper 359 to regulate the position.

The injector 61 is a pressure regulating valve, and is 600
Since the pressure is regulated to 650 kPa, it will be 36
2 presses the valve seat 358a, the needle housing 3
The fuel pressure in the fuel reservoir 358b in the same 58 is 600 to the same.
It will be 650 kilopascals. Needle 362 is seat 35
As the distance from 8a increases, the flow velocity flowing through the injector 61 increases, and the pressure drop causes the pressure in the fuel reservoir 358b to decrease. Since the pressure of the fuel pool 358b further drops when passing between the needle 362 and the valve seat 358a, the fuel pressure of the injection passage 361a is reduced to the fuel pool 358a.
It is about 1/2 of the pressure of b.

The pressure of the injection passage 361a and the combustion chamber 29
Fuel is injected into the combustion chamber 29 at a flow rate based on the pressure difference from the internal pressure. The pressure drop or pressure regulating valve of each part is set so that the flow velocity at this time is 10 to 30 m / s, preferably about 20 m / s.

In this way, the injection hole 3 of the injector 61
An injection valve M that is opened and closed by a needle 362 is arranged upstream of 61c. In addition, the injector 61 is separated from the cylinder head 23 so that the temperature does not rise easily, and the injector 61 is constantly cooled by the engine cooling water in the cooling water jacket 51 from the outer periphery of the cap 523, so that the fuel inside the injector 61 is vaporized. It is also difficult to cause carbon clogging in the descending jet flow.

Next, the fuel injection timing of the injector will be described. FIG. 10 is a fuel injection and ignition timing chart at low load and / or low speed.

In this fuel injection and ignition timing chart, the timing situation of the intermittent injection sequentially carried out in the first cylinder to the third cylinder and the spark plug 30 carried out at each crankshaft rotation in each cylinder. The high voltage current timing status is also displayed. First cylinder and second cylinder,
The bottom dead center (BDC) of each of the second cylinder and the third cylinder is out of phase by 180 °. Also, in each cylinder,
Fuel injection is performed once every three revolutions of the crankshaft, and ignition combustion occurs. In order to reduce the fluctuation of the rotation torque due to the intermittent injection combustion, the first cylinder is ignited in the first rotation of the crankshaft, the second cylinder is ignited in the second rotation, and the third cylinder is ignited in the third rotation. Therefore, ignition combustion occurs at crank angles of 480 °, 480 ° and 120 ° or less at similar intervals. Although not at equal intervals, the ignition combustion interval between the cylinders is set to 1 at high speed and high load where injection ignition is performed for each crankshaft rotation in each cylinder.
The phase of the bottom dead center is set to 18 as described above in order to set every 20 °.
This is because they are shifted by 0 °.

In the figure, a1 is the scavenging ports 41a1 and 41b.
1 is the opening timing, a2 is the scavenging port 41a
1, 41b1 is the closing timing, b1 is the opening timing of the exhaust port 44, b2 is the exhaust port 44
At the end of closing, e1 is the timing at which the injector 61 is exposed inside the combustion chamber 29, e2 is the timing at which the injector 61 is covered by the piston 26, and s is the ignition timing. A1 is the period during which the scavenging port is open during the first crankshaft rotation,
B1 indicates a period during which the exhaust port is opened at the first crankshaft rotation, and E1 indicates an exposure (fuel injection possible) period of the injector 61 at the first crankshaft rotation.

During the crankshaft rotation in which fuel is injected in intermittent injection, the first injection starts at about the bottom dead center and is completed before the scavenging ports 41a1 and 41b1 are closed. When the tip of the injection flow reaches the exhaust port 44 after being reflected by the piston top 26a, the exhaust port 44
Is completely closed by the piston 26, so there is no fuel blow-through. The first injection starts slightly earlier than e2 and ends at e2. During this injection period, the injection flow is guided by the recess 26d of the piston 26 and directed toward the spark plug 30. The timing s at which any part between the front end and the rear end of this bent injection flow just passes through the ignition gap of the spark plug 30.
Thus, a high-voltage spark current flows through the spark plug 30. Therefore, a rich mixture is formed in the ignition gap of the spark plug,
Steady ignition can be implemented. Further, the fuel injected by the first injection is larger than the fuel injected by the second injection, and the combustion chamber 29
A uniform air-fuel mixture is formed inside, stable combustion is possible, output is easily obtained, and clean exhaust gas with less HC and CO can be obtained. That is, in this embodiment, premixed combustion is directed even at low load and / or low speed, and the second injection surely forms a combustible mixture around the spark plug 30 to improve the ignitability. . The ignition timing s is after top dead center.

In this embodiment, the intermittent injection is achieved by injecting the fuel during one revolution of three revolutions of the crankshaft, but it is possible to perform the revolutionary injection of two revolutions, four, five, six revolutions or more. The injection may be performed during one rotation. The combustion cycle may be applied such that once every four rotations and once every three rotations are repeated as one cool. Further, it is desirable that the intermittent injection be sequentially performed in all the cylinders, but the intermittent injection may be performed only in a specific cylinder.

FIG. 11 is a schematic sectional view of the cylinder showing the inside of the combustion chamber 29 at the time of the second injection. In the combustion chamber 29, the fuel injected by the first injection is atomized, diffused and vaporized to form an air-fuel mixture. The dots in the figure show the fine fuel particles that have not yet vaporized. The second injection is the recess 2 formed in the piston top 26a.
It is bent at 6d and points toward the spark plug 30.

FIG. 12 is a timing chart of fuel injection and ignition at medium and high loads. Only one crankshaft rotation of one cylinder is shown until injection and ignition are performed in each cylinder every crankshaft rotation.

The injection is started at a timing b1 when the exhaust port 44 starts to open, and the injection is completed at a timing b2 when the exhaust port 44 finishes closing. Medium load
At high load, the engine speed is high and the piston speed is high. On the other hand, the velocity of the injection flow depends on the injection pressure and the combustion chamber 29.
It is almost constant regardless of the engine speed, though it depends on the pressure difference between Therefore, even if the injection is started at a crank angle faster than when the load is low, the tip qs of the injection flow is the piston top 2
Since the exhaust port 44 is completely closed by the piston 26 when it reaches the exhaust port 44 after being reflected by 6a, there is no blow-through of fuel. On the other hand, the tail end qe of the injection flow is the piston top portion 26 at the ignition timing s.
After being guided by the concave portion 26d of a, the spark plug 30 has finished passing through the spark gap portion. Therefore, most of the fuel injected before spark ignition diffuses into the combustion chamber 29 and mixes with fresh air to form a combustible mixture, so that ignition combustion is smoothly and reliably performed and high output is obtained. The resulting complete combustion is carried out, and the exhaust gas with less HC and CO can be obtained. The ignition timing s is before top dead center.

As shown in FIG. 13, the injector 61 is arranged on the cylinder side wall 22a of the opposite half facing the exhaust port 44, that is, the injector 61 is arranged on the side of the auxiliary scavenging port 41b1 from the center plane L3. The injection hole 361c is a perfect circle, and in the plane shown in FIG. 13, the angle γ of the injection flow X is set by | α2-α1 |, and the collision part of the injection flow X at the piston top portion 26c can be indicated by W. All of the injection flow X directed to the piston top 26c collides with the piston top 26c, and the vaporization of the fuel of the injection flow X directed to the piston top 26c is promoted more reliably.
The front end R1 and the rear end R2 of the collision part W are
As it moves upward, it moves toward the injector 61.

In FIG. 13, F3 is the exhaust flow, and F3 is
1 is a scavenging air flow from the main scavenging ports 41a1 on both sides,
It reverses and goes to the exhaust port 44. F2 is a scavenging air flow from the sub scavenging port 41b1. Even if the injection flow X is disturbed by the main scavenging air flow F1 and the sub scavenging air flow F2, the time to reach the exhaust port 44 is not shortened, and blow-through can be prevented.

FIG. 14 is a schematic cylinder sectional view showing a state in the combustion chamber 29 at the time of the second injection when one injector 61 has a plurality of (two in this embodiment) injection holes. In the combustion chamber 29, the fuel injected by the first injection is atomized, diffused and vaporized to form an air-fuel mixture. The jet flow has X directed toward the piston top portion 26c and Y directed toward the spark plug 30. Therefore, the first
When the injection is completed and the second injection is performed, the fuel particles diffused in a wide range in the combustion chamber 29 exist.
A more uniform air-fuel mixture can be obtained. At the time of the second injection, not only the injection flow X but also the injection flow Y is directed toward the ignition plug 30, so that a more combustible rich mixture can be formed around the ignition plug 30 during ignition.

In the second injection, the injection flow X is also guided by the recess 26d so as to be directed to the spark plug 30, but the recess 26d is eliminated and the injection flow X reflected by the piston top 26c flows around the spark plug. It suffices that a combustible rich mixture can be formed around the spark plug 30 only by the jet flow Y without directing.

In this embodiment, the injector 6
1 is provided on the cylinder side wall 22a, the cylinder head 2
It may be provided only in 3. This is indicated by Z in the figure. In this case as well, the injection flow Y is directed toward the spark plug 30, and the injection flow X is directed toward the piston top 26c.
Try to spread widely within.

FIG. 15 and FIG. 16 are plural (two in this embodiment).
(3) is a schematic cylinder plan view and a schematic cylinder cross-sectional view showing a state in the combustion chamber 29 at the time of the second injection when the injector is provided. Injectors 61A and 61B are arranged on the cylinder side wall 22a. Injector 6
The injection flow X from 1A is injected as the first injection exclusively in advance. The jet flow X is jetted laterally in the direction of the sub scavenging port 41b1 so as to spread widely in the combustion chamber 29. On the other hand, the jet flow Y from the injector 61B is ejected in advance as the second jet flow. The jet flow Y is directed to the spark plug 30. In the figure, q1s indicates the leading edge of the first injection, and q2e indicates the tail of the second injection.

17 and 18 show an embodiment of a 4-cycle engine. FIG. 17 is a sectional view of one cylinder, and FIG. 18 is a plan view of the engine. A cylinder head 701 is placed on the top of the cylinder block 700, and a piston 703 having a recess 703d that slides inside the cylinder 702 is housed. Cylinder head 70
1, two intake passages 701a and two exhaust passages 70
1b is arranged, and the lower open end of the cylinder head 701 is respectively an intake port 701c and an exhaust port 701d.
On the other hand, an intake manifold 704 and an exhaust manifold 705 are connected to the other ends, respectively. An intake valve 706 and each exhaust port 7 are provided in each intake port 701c.
An exhaust valve 707 is disposed in the 01d portion, and valve springs 711 and 71 are provided by an intake cam 709 and an exhaust cam 710, respectively.
It is opened and closed against 2. An ignition plug 713 is arranged in the cylinder center O1 on the cylinder head 70l side, which is the center of the cylinder.

The fuel distribution 715 is arranged in parallel with the common plane P10 passing through the center O1 of each cylinder, and the cylinder 70 of each cylinder is
Injectors 720 arranged parallel to each other on the two side walls are directly connected to the fuel distribution pipe 715. Fuel distribution pipe 715
A fuel pressure damper 7 that absorbs fuel pressure fluctuations is provided at the upstream end of the
21 is provided with a pressure regulating valve 722 at the downstream end for keeping the injection pressure constant.

The intake valve 706 is opened, and the piston 7
After passing through the mounting portion of the injector 720, the fuel is injected from the injector 720 in a plurality of times for each plurality of rotations of the crankshaft when the fuel has a low load, and one combustion cycle for each rotation of the crankshaft when the load is medium and high. Fuel is injected once at a time when it does not blow through. Jet flow X is piston 7
03 Point to the top. Therefore, the injected fuel exchanges heat with the piston top and the exhaust valve 707 to be vaporized, and a sufficiently uniform air-fuel mixture is formed in the combustion chamber 800 before being ignited at a timing near the top dead center. The fuel injected by the second injection is guided by the convex portion 703a on the top of the piston, and the spark plug 71
Direct to 3.

Reference numeral 80l denotes a piston ring fitted into the piston 703. An injector 720 is arranged closer to the crank chamber (not shown) than the upper piston ring 801 located when the ignition plug 713 is ignited. Protected from burnt gases.

Also in this embodiment, the fuel supply system is simplified, and the injector 720 and the fuel distribution pipe 715 are covered and protected by the intake manifold 704.

[0086]

As described above, according to the first aspect of the present invention, fuel is injected in the vicinity of the spark plug at the time of ignition at a low load with a small air-fuel mixture amount per combustion cycle and / or at a low speed with a large EGR amount. Has passed and the ignitability is improved. Moreover, the fuel injected prior to the fuel injection at the latest timing to improve ignitability forms a uniform air-fuel mixture in the combustion chamber, which increases combustion stability, which improves output and improves fuel efficiency. As a result, the emission amount of HC, CO or NOx in the exhaust gas can be reduced.
Especially in a two-cycle engine, gas exchangeability is poor and E
GR increases, and in a 4-cycle engine, exhaust gas flows back from the intake valve due to the intake valve opening before the exhaust valve closes, EGR increases, which hinders combustion stability and ignitability. However, this drawback can be complemented and reliable ignition and stable combustion can be realized.

According to the second aspect of the present invention, at a low speed or a low load, a more uniform air-fuel mixture is formed in the combustion chamber, and the fuel injected at a later timing does not pass near the ignition plug at the ignition timing. By pointing the spark plug, it becomes possible to perform firing close to stratified combustion, and stable combustion can be realized. Also, because multiple injectors are placed,
When making the total injection amount a predetermined amount, a small injector can be used, or the injection pressure can be reduced. Further, since the injection at the later timing can surely direct the spark plug, more stable combustion is possible.

According to the third aspect of the present invention, the intermittent injection is performed to make one combustion cycle per rotation of a plurality of crankshafts, and the fuel injection for the combustion cycle is divided into a plurality of injections. Can be reduced
It is possible to improve ignitability by reducing EGR and realize stable combustion. In addition, because of the intermittent injection, a larger amount of injection is required per injection than in the case of fuel injection and ignition and combustion at every crankshaft rotation, but in the combustion cycle, the injection is divided into multiple injections. The fuel is injected at the timing when the compression ratio in the chamber is low, and the pressure difference with the injection pressure becomes large, so a large amount of fuel can be injected, and a uniform air-fuel mixture is formed in the combustion chamber. Even if the injected fuel is not passing near the ignition plug at the time of ignition, by directing it toward the ignition plug, combustion close to stratified combustion can be achieved, and stable combustion can be realized.

According to the fourth aspect of the present invention, at low speed and / or low load, a more uniform air-fuel mixture is formed in the combustion chamber, and the fuel injected at a later timing is not passing near the ignition plug at the ignition point. Also, by directing the ignition plug, it is possible to perform combustion close to stratified combustion, and since it is one injector, stable combustion can be realized at low cost.

According to the fifth aspect of the invention, stable combustion can be realized by intermittent injection even in a plurality of cylinders.

According to the sixth aspect of the present invention, the heat load can be made uniform by sequentially performing intermittent injection in all the cylinders. Further, when a phase difference is provided in a plurality of cylinders, torque fluctuations in intermittent injection can be reduced.

According to the seventh aspect of the present invention, since the concentration of the homogeneous mixture can be increased, more stable combustion can be achieved.

In the eighth aspect of the present invention, more reliable premixed combustion can be performed at high speed and high load, so the combustion speed can be increased to match the high engine speed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram mainly showing one cylinder of an embodiment in which a direct injection ignition type internal combustion engine is mounted on an outboard motor.

FIG. 2 is a flow chart of fuel and air for cylinder side wall injection.

FIG. 3 is a vertical sectional view of an upper portion of one cylinder of a direct injection ignition type internal combustion engine.

FIG. 4 is a cross-sectional view of a direct injection ignition type internal combustion engine.

FIG. 5 is a cross-sectional view showing an exhaust system.

FIG. 6 is a plan view of a direct injection ignition type internal combustion engine.

FIG. 7 is a sectional view of an injector.

FIG. 8 is a cross-sectional view of the tip of the injector.

FIG. 9 is a front view of a nozzle of an injector.

FIG. 10 is a fuel injection and ignition timing chart at low load and / or low speed.

FIG. 11 is a schematic sectional view of a cylinder showing a state in a combustion chamber at the time of second injection.

FIG. 12 is a timing chart of fuel injection and ignition at medium and high loads.

FIG. 13 is a schematic plan view showing fuel injection of an injector.

FIG. 14 is a cylinder schematic cross-sectional view showing a state in the combustion chamber at the time of the second injection when one injector has a plurality of injection holes.

FIG. 15 shows a second case where a plurality of injectors are provided.
It is a cylinder schematic plan view showing the situation in the combustion chamber at the time of injection.

FIG. 16 shows a second case where a plurality of injectors are provided.
It is a cylinder schematic sectional view showing the situation in the combustion chamber at the time of injection.

FIG. 17 is a sectional view of one cylinder in the embodiment of the four-cycle engine.

FIG. 18 is a plan view of an engine in an example of a 4-cycle engine.

[Explanation of symbols]

 22 Cylinder Body 22a Cylinder Side Wall 23 Cylinder Head 26 Piston 26c Piston Top 26d Recess 29 Combustion Chamber 61 Injector X Jet Flow

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location F02D 41/34 9523-3G F02D 41/34 H 41/36 41/36 B 43/00 301 43 / 00 301B 301J F02M 45/02 F02M 45/02 61/14 310 61/14 310S 310U 61/18 360 61/18 360J

Claims (8)

[Claims] Claims: 1. A fuel is directly injected into a combustion chamber formed by a cylinder head, a cylinder body and a piston from an injector arranged on the wall of the combustion chamber, and ignition is ignited by an ignition plug provided in the cylinder head. In the direct injection ignition type internal combustion engine, the fuel is injected at least twice at low speed and / or low load, and the fuel injected at the latest timing is ignited at the timing while passing near the spark plug. A direct injection ignition type internal combustion engine characterized by the above. 2. At least two injectors are arranged on a combustion chamber wall formed by a cylinder head, a cylinder body and a piston, and ignition is ignited by an ignition plug provided on the cylinder head after fuel injection from the injectors is completed. In the above direct injection ignition type internal combustion engine, the injection timings of at least two injectors are moved forward and backward at the time of low speed and / or low load, and fuel from the injectors injected at the latest timing is injected toward the vicinity of the spark plug. Direct injection ignition type internal combustion engine characterized in that 3. An injector having a plurality of injection holes for generating fuel injection flows directed in a plurality of directions is arranged on a combustion chamber wall formed by a cylinder head, a cylinder body and a piston, and fuel injection from the injector is performed. A direct injection ignition internal combustion engine in which one fuel injection flow is directed near the ignition plug in a direct injection ignition internal combustion engine in which ignition plug is provided to ignite after completion. organ. 4. At a low speed and / or a low load, intermittent fuel injection is performed during one revolution per multiple revolutions of the crankshaft, and fuel is injected into the combustion chamber at least twice. The direct injection ignition type internal combustion engine according to any one of claims 1 to 3. 5. A fuel injection system comprising a plurality of cylinders, wherein fuel is injected during one revolution per a plurality of revolutions of the crankshaft in at least one cylinder at low speed and / or low load, and intermittent injection is performed. Item 5. A direct injection ignition type internal combustion engine according to any one of items 4. 6. A direct injection ignition system according to any one of claims 3 to 4, wherein a plurality of cylinders are provided, and intermittent injection is sequentially performed in all cylinders at low speed and / or low load. Internal combustion engine. 7. The fuel injection amount is divided into two injections at low speed and / or low load, and the injection amount of the first injection injected at early timing is q1, and the injection amount of the second injection injected at late timing. 7. The direct injection ignition type internal combustion engine according to claim 1, wherein the injection amount q1 is larger than the injection amount q2. 8. The fuel injection system according to claim 1, wherein the injected fuel is ignited at the timing when the injected fuel has completed passing through the vicinity of the spark plug.
A direct injection ignition type internal combustion engine according to any one of 1.