JPH0726957A - Auxiliary combustion chamber type diesel engine - Google Patents

Abstract

PURPOSE:To improve mixing performance of air and combustion expansion gas by facing a gas deviation guide surface formed by providing a gas deviation part on at least one side of center parts of a cylinder head surface and a piston top surface, forward turning gas flow of turning direction opposite to intake swirl. CONSTITUTION:An auxiliary combustion chamber 1 is provided in a cylinder head 23, and a main combustion chamber 5 is provided in a cylinder 22. An injection port 4 is provided on a position which is eccentrically from a cylinder center axial line 3, the injection port 4 is faced to the center part of a cylinder 22, combustion expansion gas injected from the injection port 4 is formed as a pair of turning gas flows 6, 7 which are positioned on both sides of an injection center line 12 and whose turning direction are opposite to each other, so that intake swirl 45 is generated. A gas deviation part 46 is provided on at least one side of a cylinder head surface 9 and a piston top surface 8, a gas deviation guide surface 47 is formed on the rise surface thereof, and the deviation guide surface 47 is faced forward the turning gas flow 7 of turning direction opposite to the intake swirl 45. It is thus possible to improve mixing performance in the main combustion chamber 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary combustion chamber type diesel engine, and more particularly to a diesel engine capable of effectively mixing air in a main combustion chamber with combustion expansion gas.

[0002]

2. Description of the Related Art The general structure of a secondary combustion chamber type diesel engine is as follows. That is, the sub combustion chamber is provided in the cylinder head, and the main combustion chamber is provided in the cylinder.
An injection port is provided in the cylinder head at a position eccentric from the cylinder center axis line, and the injection port is directed toward the center of the cylinder. As this type of engine, there is an engine in which an intake swirl is generated along the inner peripheral surface of the cylinder in the main combustion chamber.

[0003]

In the above intake swirl type engine, it is expected that the intake swirl will effectively mix the air in the main combustion chamber with the combustion expansion gas injected from the injection port to improve the combustion performance. Was done. But,
In reality, the combustion performance is not much improved compared to an engine without intake swirl. The reason is considered that the air in the main combustion chamber and the combustion expansion gas are not mixed effectively.

An object of the present invention is to effectively mix the air swirled by the intake swirl and the combustion expansion gas in the auxiliary combustion chamber type diesel engine.

[0005]

As described below, the present invention deflects a part of the combustion expansion gas toward the front of a specific swirling gas flow. In the past, however, the combustion expansion gas injected from the injection port was used. Since it has not been confirmed what kind of flow state is exhibited in the main combustion chamber, there is no room for the idea of the present invention.

The method of confirming the flow state of the combustion expansion gas in the main combustion chamber, which is performed by the inventors of the present invention this time, is as follows. Vaseline mixed with molybdenum disulfide powder was thinly applied to the top surface of the piston, and the engine was motorized. With this configuration, the petroleum jelly is melted by the compression heat generated in the main combustion chamber when the piston moves up. Then, when the piston descends from the top dead center, air is ejected from the injection port into the main combustion chamber due to the pressure difference generated between the auxiliary combustion chamber and the main combustion chamber, and this air flows along the top surface of the piston. Vaseline flows along with the flow of air, and molybdenum disulfide powder is aligned along the flow path.

Therefore, after motoring for a predetermined time,
By taking out the piston and visually observing the orientation of the molybdenum disulfide powder, the flow state of air in the main combustion chamber could be confirmed. As a result, when viewed in a direction parallel to the center axis of the cylinder, the inventors have found that the above-mentioned air is located at both sides of this injection axis and a straight flow that flows forward along the injection axis of the injection port. It was confirmed that a pair of swirling flows opposite to each other were formed. Then, based on this knowledge, when the inventors actually drive the engine,
It was estimated that the combustion expansion gas ejected from the nozzle had the same flow state as the air in the main combustion chamber.

Next, based on this estimation, the inventors actually operated the engine for a predetermined time, took out the piston, and observed the carbon adhering to the top surface of the piston in detail. It was confirmed that they were attached in almost the same orientation, and the validity of the above estimation was confirmed. Furthermore, in the case of engines of the same individual, the position of each swirl center of the swirling gas flow is almost constant even if the engine speed is different or the fuel injection amount to the auxiliary combustion chamber is different. I also confirmed.

Furthermore, the inventors of the present invention use the above confirmation method.
Regarding the conventional intake swirl engine, the flow state of combustion expansion gas was confirmed. As a result, as shown in FIG. 6, the swirling gas flow 1 in the same swirling direction as the intake swirl 145
The swirling radius of 06 was large, and the swirling radius of the swirling gas flow 107 in the reverse swirling direction was small. It is considered that the swirling gas flow 106 is accelerated by the acceleration by the intake swirl 145, and the swirling gas flow 107 is suppressed by the collision by the intake swirl 145. Then, the inventors confirmed that a large gas unreachable region 148 was formed in front of the swirling gas flow 107, and found out a factor that does not improve the mixing performance of the combustion expansion gas and air in the main combustion chamber. . In the figure, reference numeral 104 is a nozzle, 140 is a gas passage groove, and 141 is a gas passage groove 140.
It is the starting point of.

In response to this result, the inventors of the present invention deflect a part of the combustion expansion gas in front of the swirl gas flow 107 in the reverse swirl direction with respect to the intake swirl 145.
The present invention has been accomplished on the assumption that the gas unreachable region 148 in front of 7 is reduced or disappears.

[0011]

[Means for Solving the Problems]

(First Invention) In the first invention, as illustrated in FIG. 1, the sub combustion chamber 1 is provided in the cylinder head 23, and the main combustion chamber 5 is provided in the cylinder 22. The cylinder head 23 is provided with the injection port 4 at a position eccentric from the cylinder center axis line 3,
By directing the injection port 4 toward the center of the cylinder 22, the combustion expansion gas injected from the injection port 4 advances straight forward along the injection axis 12 of the injection port 4 when viewed in a direction parallel to the cylinder center axis 3. Gas flow 27 and this injection axis 1
It is arranged on both sides of No. 2 and forms a pair of swirling gas flows 6 and 7 whose swirling directions are opposite to each other. Then, in the main combustion chamber 5, the intake swirl 45 along the inner peripheral surface of the cylinder 22.
Is configured to occur.

Further, when viewed in a direction parallel to the cylinder center axis 3, at least one of the central portions of the cylinder head surface 9 and the piston top surface 8 facing the main combustion chamber 5 has a raised gas deflecting portion 46. Is provided, and a gas deflection guide surface 47 is formed on the rising surface of the gas deflection portion 46. The gas deflection guide surface 47 extends from the central portion of the main combustion chamber 5 to the swirling gas flow 7 in the direction opposite to the intake swirl 45. The feature is that it is directed to the front of.

(Second Invention) As shown in FIG. 1, the second invention is such that, in the first invention, a gas passage groove 40 is recessed in the piston top surface 8 and viewed in a direction parallel to the cylinder center axis 3. And a starting end portion 41 of the gas passage groove 40 is formed at a position overlapping the injection port 4, and the injection axis 1 of the injection port 4 extends from the starting end portion 41.
The gas passage groove 40 was led out forward along the line 2.

A cylinder head surface 9 overlapping the gas passage groove 40 when viewed in a direction parallel to the cylinder center axis 3,
A gas deflecting portion 46 is provided on at least one of the inner bottom surfaces of the gas passage groove 40.

(Third Invention) As shown in FIG. 1, the third invention is either the first invention or the second invention, and in any one of the first invention and the second invention, the cylinder head surface 9 and the piston top surface facing the main combustion chamber 5 are shown. At least one of the valve recesses 10 and 11 is recessed in at least one of
When viewed in a direction parallel to, the pair of valve recesses 10.1
1 was distributed to both sides of the injection axis 12 of the injection port 4.

When viewed in a direction parallel to the center axis 3 of the cylinder, the swirl centers 14 and 15 of the swirl gas flows 6 and 7 are located in the pair of valve recesses 10 and 11, respectively. Characterize.

(Fourth Invention) As shown in FIG. 1, a fourth invention is provided with a total of three intake valves 32 and 33 and exhaust valves 35 in any one of the first to third inventions. It is characterized by that.

(Fifth Invention) As shown in FIG. 4, a sixth invention is any one of the first invention to the fourth invention, in which an intake port 28 is provided in the cylinder head 23 and the intake port 28 is provided. An intermediate intake valve port 30 and a terminal intake valve port 31 are provided in the intermediate part and the terminal part.

When an imaginary transverse line 56 orthogonal to the cylinder center axis 3 is assumed in the radial direction of the cylinder 22, the regions on both sides of the imaginary transverse line 56 when viewed in a direction parallel to the cylinder center axis 3. 54/57, one area 5
The intake port 28 is located at 7.

The intake introduction port portion 58 on the starting end side of the intake port 28 is formed in parallel with the virtual transverse line 56, and the end of the intermediate intake valve port 30 from the central point 59 of the virtual transverse line 56 is formed. By arranging the center point 60 of the intake valve port 31 close to each other, the center point passage line 61 passing through both center points 59 and 60 is formed to be the axis line 6 of the intake introduction port portion 58.
Tilt to 2.

Further, the inter-valve port portion 63 located between the center points 59 and 60 is formed parallel to the center-point passage line 61, so that the inter-valve port portion 63 is formed.
Is inclined with respect to the direction of the intake introduction port portion 58.

(Sixth Invention) A sixth invention is the fifth invention, as illustrated in FIG.
When viewed in a direction parallel to the cylinder center axis 3 of the peripheral wall 64, the outward portion 65 on the side far from the virtual transverse line 56 is curved outwardly in a bulge shape.

(Seventh Invention) As shown in FIG. 4, a seventh invention is the invention of either the fifth invention or the sixth invention, wherein the intake introduction port portion 58 is directed from the start end to the end. The feature is that the diameter is reduced.

[0024]

(Operation and Effect of the Invention) (First Invention) As illustrated in FIG. 1 (A), a part of the combustion expansion gas is guided by a gas guide deflecting surface 47, and a swirling gas in a reverse swirling direction to the intake swirl 45. Deflected ahead of stream 7,
The gas unreachable region 48 in front of the swirling gas flow 7 decreases or disappears. Therefore, the mixing performance of the combustion expansion gas and the air in the main combustion chamber 5 is improved, and the output performance is improved.

(Second Invention) As shown in FIG. 1A, the combustion expansion gas ejected from the nozzle 4 is passed through the gas passage groove 40.
Since it passes through the inside with little resistance, the flow velocity increases. Therefore, the mixing performance of the combustion expansion gas and the air in the main combustion chamber 5 is improved, and the output performance is further improved.

(Third Invention) As illustrated in FIG. 1 (A), the air in the pair of valve recesses 10 and 11 is surrounded by the swirling gas flows 6 and 7 and is dragged by the swirling gas flows 6 and 7. Turn in the same direction as flows 6 and 7 as indicated by arrows 18 and 19. In this case, the specific gravity of air is 6
Since it is larger than that of No. 7, due to the centrifugal force difference, the air diffuses into the swirling gas flows 6 and 7 as shown by arrows 20 and 21, and these are effectively mixed, and the air in the main combustion chamber 5 is Utilization rate of. Therefore, the mixing performance of the combustion expansion gas and the air in the main combustion chamber 5 is improved, and the output performance is further improved.

(Fifth Invention) As illustrated in FIG. 4, the intake air 67 that is about to pass through the inter-valve port portion 63 will proceed straight by the inertial force while being directed by the intake introduction port portion 58. However, this port portion between valve ports 6
Since the direction of 3 is inclined with respect to the direction of the intake introduction port portion 58, the intake air 67 is guided to the end port portion 68 by the outer portion 65 of the peripheral wall 64 of the inter-valve port portion 63, and its arc shape is formed. Is sucked into the cylinder 22 from the terminal intake valve port 31 while wrapping around along the wall of the cylinder.

Therefore, the intake air 67 sucked into the cylinder 22 from the terminal intake valve opening 31 is directed along the inner peripheral surface of the cylinder 22 and becomes a turbulent flow near the terminal intake valve opening 31 which becomes an intake resistance. Is prevented, high-speed intake swirl 45 is generated in the main combustion chamber 5, the mixing performance of the combustion chamber expansion gas and air in the main combustion chamber 5 is improved, and the output performance is further improved.

(Sixth Invention) As illustrated in FIG. 4, since the intake air 67 guided by the outer side portion 65 is smoothly guided by its curvature, the guide resistance of the intake air 67 can be reduced, and this outward movement The speed of the intake swirl 45 is further increased as compared with the case where the portion 65 is formed straight.

(Eighth Invention) As illustrated in FIG. 4, the flow velocity of the intake air flowing from the intake port introducing portion 58 into the inter-valve port portion 63 is increased, and the flow velocity of the intake air sucked into the cylinder 22 is increased. Therefore, the speed of the intake swirl 45 in the cylinder 22 is further increased.

[0031]

Embodiments of the present invention will be described with reference to the drawings.
First, a first embodiment will be described with reference to FIGS.
The first embodiment is a vertical multi-cylinder diesel engine equipped with a sub-chamber combustion chamber, and its structure is as follows. That is, as shown in FIG. 1B, the cylinder head 23 is assembled on the upper side of the cylinder 22, the piston 24 is fitted in the cylinder 22, and the main combustion chamber 5 is inserted in the cylinder 22.
Are formed. A substantially spherical vortex chamber type auxiliary combustion chamber 1 facing the fuel injection nozzle 2 is formed in the cylinder head 23, and the auxiliary combustion chamber 1 is connected to the main combustion chamber 5 via the injection port 4.
Is in communication with.

As shown in FIG. 1A, the injection port 4 is provided near the inner peripheral surface of the cylinder 22, that is, at a position eccentric from the cylinder center 3. As shown in FIG. 2, the injection port 4 is composed of a main injection port 25 and a pair of left and right side injection ports 26, 26 along the left and right sides of the main injection port 25.

The main injection port 25 is formed in an obliquely cylindrical shape, and its axis 25a is inclined at an angle of elevation of about 45 ° with the cylinder head surface 9 facing the main combustion chamber 5 as a reference plane, and the cylinder center axis 3 Is directed to. This axis 2
5a should be directed to the center of the cylinder 22,
It may be offset from the cylinder center axis 3 to some extent.

The side jet holes 26, 26 are formed in a downwardly expanding frustoconical shape, and their axes 26a, 26a are shown in FIG. 2 (A).
As seen from the side, the axis 25a of the main injection port 25 is seen from the side.
As in the case of Fig. 2 (B)
When viewed from the front, the lower side is inclined so as to spread outward as shown in FIG. The elevation angle of the axis 25a of the main injection port 25 and the elevation angle of the axis 26a of the side injection port 26 are not particularly limited, but are preferably about 40 ° to 50 °.

In such a sub-chamber type combustion chamber, the sub-combustion chamber 1
The combustion expansion gas ejected from the nozzle via the nozzle hole 4 flows in the main combustion chamber 5 as follows. That is, as shown in FIG. 1 (A), when viewed in a direction parallel to the cylinder center axis line 3,
The combustion expansion gas ejected from the injection port 4 is located on both sides of the straight gas flow 27 forward along the injection axis 12 of the injection port 4 and the injection axis 12 of the injection port 4, and has a pair of swirling directions opposite to each other. And the swirling gas streams 6 and 7 are formed. The injection axis 12 of the injection port 4 is on an extension of the axis 25a of the main injection port 25.

The positions of generation of the respective swirl centers 14 and 15 of the pair of swirl gas flows 6 and 7 are as follows. That is, when a virtual transverse line 13 orthogonal to the injection axis 12 of the injection port 4 is assumed in the radial direction of the cylinder 22, each swivel center 14 is located at a position deviated from the virtual transverse line 13 toward the injection port 4 side.
15 is generated. When the injection port 4 is composed of only the main injection port 25, the swirling radii of the pair of swirling gas flows 6 and 7 are small, but the swirling centers 14 and 15 are generated at substantially the same positions as in this embodiment.

Further, an intake swirl 45 is formed along the cylinder 22 in the main combustion chamber 5. Means for forming the intake swirl 45 will be described later. This intake swirl 45
Swirls in the counterclockwise direction, the swirling radius of swirling gas flow 6 swirling in the counterclockwise direction increases, and the swirling radius of swirling gas flow 7 swirling in the clockwise direction decreases.

In this embodiment, in order to effectively mix the air swirled by the intake swirl 45 and the combustion expansion gas, the following constitution is adopted. That is, a gas-deflecting portion 46 in the shape of a ridge is provided at the center of the piston top surface 8,
The gas deflection guide surface 4 is provided on the rising surface of the gas deflection portion 46.
7 is formed, and this gas deflection guide surface 47 is curved with a gentle inclination from the central portion of the main combustion chamber 5 toward the front of the swirling gas flow 7 in the direction opposite to the intake swirl 45. The tangential inclination angle of the gas deflection guide surface 47 is determined by the injection port 4
It is desirable that the angle is within 45 ° with respect to the injection axis 12 of. The gas deflecting portion 46 may be formed at the center of the cylinder head surface 9 facing the main combustion chamber 5, or may be formed on both the piston top surface 8 and the cylinder head surface 9.

According to this structure, a part of the combustion expansion gas is guided by the gas deflection guide surface 47, and the intake swirl 4 is moved.
5 is deflected to the front of the swirling gas flow 7 in the direction opposite to the swirling direction 5, and the gas unreachable region 48 in front of the swirling gas flow 7 is reduced or disappears.

Further, in this embodiment, in order to increase the flow velocity of the combustion expansion gas, the piston top surface 8 is provided with the gas passage groove 40. The structure of the gas guide groove 40 is as follows. That is, when viewed in a direction parallel to the cylinder center axis 3, the starting end portion 41 of the gas passage groove 40 is formed at a position overlapping the injection port 4, and the injection axis line 1 of the injection port 4 is formed from the starting end portion 41.
A gas passage groove 40 is led forward along the line 2. The gas guide groove 40 is formed so that the width thereof gradually increases and the depth thereof gradually decreases as the distance from the start end 41 of the gas guide groove 40 increases along the injection axis 12 of the injection port 4.

The left and right portions of the gas passage groove 40 are formed in the injection axis 12 of the pair of left and right valve recesses 10 and 11.
The gas passage groove 40 overlaps with each of the portions 42 and 43 closer to each other, and the central end portion of the gas passage groove 40 overlaps with a portion 44 of the front-side valve recess 37 closer to the virtual transverse line 13. Then, the gas deflection portion 46 is provided on the inner bottom surface of the gas passage groove 40. The gas deflection portion 46 is raised at the same height as the piston top surface 8. When the gas guide deflector 46 is provided on the cylinder head surface 9,
Gas passage groove 40 when viewed in a direction parallel to the cylinder center axis 3
It is provided at a position where
The gas guide deflecting portion 46 is allowed to enter the gas passage groove 40 at the time of jetting from. According to such a configuration, the combustion expansion gas ejected from the injection port 4 is not allowed to pass through the gas passage groove 40.
Since it passes through the inside with less resistance, the flow velocity of the combustion expansion gas increases.

As shown in FIGS. 1B and 1C,
An intake port 28 and an exhaust port 29 are formed in the cylinder head 23, and the intermediate intake valve port 3 of the intake port 28 is formed.
Intake valves 32 and 33 are openably and closably provided at the 0 and terminal intake valve ports 31, respectively, and an exhaust valve 35 is openably and closably provided at an exhaust valve port 34 of the exhaust port 29. This is a so-called three-valve structure. The intake / exhaust valves 32, 33, 35 are opened and closed at a predetermined timing via a valve operating device including a push rod 36 and the like. And, these intake and exhaust valves 32
As shown in FIG. 1 (A), a pair of left and right valve recesses 10
11 and the front valve recess 37 are recessed. Each recess center 16 of this pair of valve recesses 10 and 11
17 are set to have essentially the same distance from the injection port 4.

In order to effectively mix the air in the pair of valve recesses 10 and 11 with the pair of swirling gas flows 6 and 7, as shown in FIG. Looking at the direction, a pair of valve recesses 10 and 11
A pair of swirling gas flows 6.7 at each recess center
The turning centers 14 and 15 of the above are coincident with or brought close to each other.

According to this structure, the air in the pair of valve recesses 10 and 11 is surrounded by the swirling gas flows 6 and 7 and is dragged by the swirling gas flows 6 and 7 in the same direction as the vortex winding 6 and 7. It turns like 18 ・ 19. in this case,
Since the specific gravity of air is larger than that of the combustion expanded gas, the air is diffused into the swirling gas flows 6 and 7 as indicated by arrows 20 and 21 due to the centrifugal force difference, and the mixing of these is effectively performed.

Further, as shown in FIG. 1A, the front valve recess 37 is set on the injection axis 12 of the injection port 4 when viewed in a direction parallel to the cylinder center axis 3. Therefore, the air in the front valve recess 37 and the straight gas flow 27
It is effectively mixed with. The recess center 38 of the valve recess 37 is set near the injection axis 12 of the injection port 4. It is desirable that the position of the recess center 38 essentially coincides with the injection axis 12.

Next, the structure of the cylinder head of the first embodiment will be described in detail. As shown in FIG. 4A, when a second virtual transverse line 56 orthogonal to the cylinder center axis 3 and the crank axis 70 is assumed in the radial direction of the cylinder 22, when viewed in a direction parallel to the cylinder center axis 13. , This second
The intake port 28 is located in the rear region 57 of the front region 54 and the rear region 57 located on both sides of the imaginary transverse line 56. The intake port 28 is connected to the cylinder head 23.
Is formed from the right wall 53 to the left. The intake introduction port portion 58 on the starting end side of the intake port 28 is formed parallel to the second virtual transverse line 56. The intake introduction port portion 58 may be essentially parallel to the second virtual transverse line 56. An intermediate intake valve opening 30 and a terminal intake valve opening 31 are provided at the intermediate portion and the terminal portion of the intake port 28,
These are arranged separately on the left and right of the crank axis 70.

The center point 60 of the end intake valve opening 31 is located closer to the second virtual transverse line 5 than the center point 59 of the intermediate intake valve opening 30.
By being placed close to 6 both center points 59.6
A center point passage line 61 passing through 0 is inclined with respect to the axis 62 of the intake introduction port portion 58. And both center points 5
Since the inter-valve port portion 63 located between 9 and 60 is formed parallel to the center point passage line 61, the orientation of the inter-valve port portion 63 with respect to the direction of the intake introduction port portion 58. Is tilted. The port portion 63 between the valve openings is
It suffices if it is essentially parallel to the center point passage line 61. Reference numeral θ in the drawing is the inclination angle of the center point passage line 61 with respect to the axis line 62 of the intake introduction port portion 58.

According to such a configuration, the intake air 67 passing through the inter-valve port portion 63 tries to proceed straight by inertial force while being directed by the intake introduction port portion 58. Since the orientation of the inter-valve port portion 63 is inclined with respect to the orientation of the intake introduction port portion 58, this intake air 67 is generated by the peripheral wall 64 of the inter-valve port portion 63.
Is guided to the end port portion 68 by the outer side portion 65, and is sucked into the cylinder 22 from the end intake valve port 31 while turning around along the arcuate wall. For this reason,
The intake air 67 that is sucked into the cylinder 22 from the terminal intake valve opening 31 is directed along the inner peripheral surface of the cylinder 22, and the occurrence of turbulence near the terminal intake valve opening 31 that serves as intake resistance is prevented. The speed of the intake swirl 45 increases.

Further, of the peripheral wall 64 of the inter-valve port portion 63, the outer side portion 65 on the side far from the second virtual transverse line 56 when viewed in a direction parallel to the cylinder center axis 3 bulges outward. Is curved into a shape. Therefore, since the intake air 67 guided by the outer portion 65 is smoothly guided by the curve, the guide resistance of the intake air 67 can be reduced,
Compared with the case where the outer portion 65 is formed straight,
The speed of the intake swirl 45 further increases.

Further, the intake introduction port portion 58 is reduced in diameter from its starting end toward its terminating end. Therefore, the flow velocity of the intake air flowing from the intake port introduction portion 58 into the inter-valve port portion 63 is increased, the flow velocity of the intake air sucked into the cylinder 22 is increased, and the speed of the intake swirl 45 is further increased.

The exhaust port 29 is connected to the second virtual transverse line 5
It is formed in a region 54 on the front side of 6 from the top of the crank axis 70 to the left. An exhaust valve port 34 is provided at the starting end of the exhaust port 29. The sub combustion chamber 1 is arranged behind the second virtual transverse line 56 and on the right side of the crank axis 70. The push rod chamber 71 is arranged on the second transverse line 56 to the left of the crank axis 70.
Reference numeral 72 in the drawing denotes a head bolt insertion hole, which is arranged at a position surrounding the cylinder 22 so that a total of 6 holes are distributed every 60 °.

The second embodiment of FIG. 5 is a modification of the first embodiment shown in FIG. 1, in which a pair of left and right valve recesses 10 and 11 are formed on the cylinder head surface 9 facing the main combustion chamber 5.
The valve recesses 10 and 11 are formed concentrically with the exhaust valve opening 34 and the intermediate intake valve opening 30. The pair of left and right valve recesses 10 and 11 are not limited to one of the cylinder head surface 9 and the piston top surface 8 facing the main combustion chamber 5,
You may form in both. The structure of the other elements of this second embodiment is similar to that of the first embodiment.

The contents of each embodiment of the present invention are as described above, but the present invention is not limited to the above embodiments. For example, the engine format is not limited to vertical, but horizontal,
It may be inclined. The auxiliary combustion chamber 1 is not limited to the vortex chamber but may be a pre-combustion chamber.

Further, the recess centers 16 and 17 of the pair of valve recesses 10 and 11 are not limited to the positions deviated from the virtual transverse line 13 to the injection port 4 side, but may be on the virtual transverse line 13 or from the virtual transverse line 13. You may arrange | position in the position biased to the opposite side to the injection port 4. In this case, the pair of valve recesses 10 and 11
Of each recess center 16 and 17 and a pair of swirling gas flows 6 and 7
It is necessary to reduce the elevation angle of the injection port 4 so that the respective swirl centers 14 and 15 of the swirl centers 14 and 15 of the swirl centers 14 and 15 of the swirl gas flows 6 and 7 are separated from the spout 4. .

However, it is desirable that the recess centers 16 and 17 of the valve recesses 10 and 11 are arranged at positions deviated from the virtual transverse line 13 toward the injection port 4 side, as in the above-described embodiments. This is because as the positions of the valve recesses 10 and 11 and the swirling gas flows 6 and 7 are closer to the injection port 4, the swirling gas flows come into contact with the air in the valve recesses 10 and 11 at a higher flow rate, and the mixing of these is performed more effectively. .

The swirl centers 14 and 15 of the pair of swirl gas flows 6 and 7 may be located in the pair of valve recesses 10 and 11 when viewed in a direction parallel to the cylinder center axis 3. However, the effectiveness of mixing the air in the pair of valve recesses 10 and 11 with the pair of swirling gas flows 6 and 7 tends to increase as the swirl centers 14 and 15 approach the recess centers 16 and 17, respectively. Each turning center 1 is located in each area surrounded by an imaginary circle having a radius of 2/3 of the radius of each valve recess 10 and 11 with each recess center 16 and 17 as the center.
It is desirable to position 4.15.

Furthermore, with the center of each recess 16 and 17 as the center, 1/2 or 1 of the radius of each valve recess 10 and 11.
It is more desirable to locate each of the swivel centers 14 and 15 within a region surrounded by a virtual circle having a radius of / 4 or 1/5. In addition, each turning center 14 and 15 has a valve recess 10 and
As long as it is located within 11 or within the area surrounded by the virtual circle, the distances from the injection port 4 to the recess centers 16 and 17 are not necessarily equal.

In each of the embodiments of the present invention, each of the swirl centers 14 of the pair of swirl gas flows 6 and 7 produced by the combustion expansion gas ejected from the injection port 4 naturally flowing along the piston top surface 8. The valve 15 is located in the pair of valve recesses 10 and 11, and is not a structure for forcibly deflecting the flow of the combustion expansion gas toward the pair of valve recesses by a gas guide groove or the like. When the combustion expansion gas is forcibly deflected by the gas guide groove, etc., most of it overflows from the gas guide groove before reaching the pair of valve recesses, and only a small amount of combustion expansion gas is introduced into the pair of valve recesses. .

The gas passage groove 40 described in the above embodiment is used.
Is used only to reduce the throttling resistance between the cylinder head surface 9 facing the main combustion chamber 5 and the piston top surface 8, and directs the combustion expansion gas to the pair of valve recesses 10 and 11. It is not for forced deflection. According to the confirmation by the present inventors, the positions of the swirl centers 14 and 15 of the pair of swirl gas flows 6 and 7 are determined by the gas passage groove 4
It can be essentially at the same position with or without zeros. From this, it is understood that the combustion expansion gas is not forcibly deflected toward the pair of valve recesses 10 and 11 by the gas passage groove 40.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a first embodiment of the present invention, and FIG.
FIG. 1A is a plan view of a piston fitted in a cylinder, FIG.
1B is a sectional view taken along line BB in FIG. 1A, FIG. 1C is a sectional view taken along line CC in FIG. 1A, and FIG. 1D is D- in FIG. 1A. It is a D line sectional view.

FIG. 2 is a perspective view of a piston head used in the first embodiment of the present invention.

FIG. 3 is a schematic view of a nozzle used in the first embodiment of the present invention,
FIG. 3 (A) is a perspective view of the nozzle seen from the side, and FIG. 3 (B).
[Fig. 3] is a perspective view of a nozzle seen from the front side.

4A and 4B are views illustrating a cylinder head used in the first embodiment of the present invention, FIG. 4A is a cross-sectional plan view, and FIG. 4B is a cross-sectional view taken along line BB of FIG. 4A. is there.

FIG. 5 is a vertical sectional view of a cylinder head used in a second embodiment of the present invention.

6A and 6B are views for explaining a conventional technique, FIG. 6A is a plan view of a piston fitted in a cylinder, and FIG. 6B is FIG.
6A is a cross-sectional view taken along line BB in FIG. 6A, and FIG. 6C is C in FIG.
It is a -C line cross section.

[Explanation of symbols]

1 ... Secondary combustion chamber, 3 ... Cylinder center axis line, 4 ... Injection port, 5 ...
Main combustion chamber, 6/7 ... pair of swirling gas flows, 8 ... Piston top surface, 9 ... Cylinder head surface, 10/11 ... Left and right pair of valve recesses, 12 ... 4 injection axis, 14.15 ... 6/7
Of the center of rotation, 22 ... Cylinder, 23 ... Cylinder head,
28 ... Intake port, 30 ... Intermediate intake valve port, 31 ... End intake valve port, 32.33 ... Intake valve, 35 ... Exhaust valve, 40 ... Gas passage groove, 41 ... 40 Start end portion, 45 ... Intake swirl,
46 ... Gas deflection part, 47 ... Gas deflection guide surface, 54 ... (Front side) area, 56 ... (Second) virtual transverse line, 57 ... (Rear side) area, 58 ... Intake inlet port portion, 59 ... 30 Center point of 60, 31 center point of 61, 61 ... center point passing line, 62
... 58 axis line, 63 ... valve opening port portion, 64 ... 63 peripheral wall, 65 ... outer portion.

Claims (7)

[Claims] 1. A cylinder head (23) is provided with an auxiliary combustion chamber (1), a cylinder (22) is provided with a main combustion chamber (5), and the cylinder head is located at a position eccentric from the cylinder center axis (3).
A nozzle (4) is provided in (23), and this nozzle (4) is connected to a cylinder (2
By pointing to the center of 2), the cylinder center axis
When viewed in a direction parallel to (3), the combustion expansion gas injected from the injection port (4) is directed forward along the injection axis (12) of the injection port (4) along with the straight gas flow (27) and this injection. A pair of swirling gas flows (6) located on both sides of the axis (12) and having opposite swirling directions.
A sub-combustion chamber type diesel engine configured so as to form (7) and in which an intake swirl (45) along the inner peripheral surface of the cylinder (22) is generated in the main combustion chamber (5). When viewed in a direction parallel to the cylinder center axis (3), the main combustion chamber
Cylinder head surface (9) facing inside (5) and piston top surface (8)
At least one of the central portions of the gas deflection portion (46) is provided with a raised gas deflection portion, and a gas deflection guide surface (47) is formed on the rising surface of the gas deflection portion (46). The sub-combustion chamber type diesel engine is characterized by directing 47) from the central portion of the main combustion chamber (5) to the front of the swirling gas flow (7) in the reverse swirling direction with the intake swirl (45). 2. The auxiliary combustion chamber type diesel engine according to claim 1, wherein the gas passage groove is formed on the piston top surface (8).
(40) is recessed, and when viewed in a direction parallel to the cylinder center axis (3), the starting end (41) of this gas passage groove (40) is connected to the injection port (4).
It is formed at a position where it overlaps with the starting end (41) and the injection port (4)
Guide the gas passage groove (40) forward along the injection axis (12) of the gas passage groove when viewed in a direction parallel to the cylinder center axis (3).
Cylinder head surface (9) overlapping with (40) and gas passage groove
At least one of the inner bottom surfaces of (40) has a gas deflecting portion (4
A sub-combustion chamber type diesel engine, which is provided with 6). 3. A sub-combustion chamber type diesel engine according to claim 1, wherein:
At least a pair of valve recesses (10) and (11) are provided on at least one of the cylinder head surface (9) and the piston top surface (8) facing the main combustion chamber (5), and the cylinder center axis (3) ), The pair of valve recesses
(10)-(11) are distributed to both sides of the injection axis (12) of the injection port (4), and when viewed in a direction parallel to the cylinder center axis (3), the pair of valve recesses (10)-(11) ), The respective swirl centers (14) and (15) of the pair of swirl gas flows (6) and (7) are respectively located inside the auxiliary combustion chamber type diesel engine. 4. The auxiliary combustion chamber type diesel engine according to any one of claims 1 to 3, wherein a total of three intake valves (32), (33) and exhaust valves (35) are provided. A sub-combustion chamber type diesel engine characterized by the following. 5. The auxiliary combustion chamber type diesel engine according to any one of claims 1 to 4, wherein a cylinder head (23) is provided with an intake port (28), and an intermediate portion of the intake port (28) is provided. Part and end part of the intermediate intake valve port (3
0) and the terminal intake valve port (31) are provided, and assuming a virtual transverse line (56) orthogonal to the cylinder center axis (3) in the radial direction of the cylinder (22), the cylinder center axis (3) Seen in a parallel direction, one of the regions (54) and (57) on both sides of the virtual crossing line (56) is
The intake port (28) is located, and the intake introduction port portion on the starting end side of the intake port (28)
(58) is formed parallel to the imaginary transverse line (56), and with respect to the imaginary transverse line (56), the end intake valve opening (31) is located closer to the center point (59) of the intermediate intake valve opening (30). By placing the center points (60) close to each other, both center points (59) and (60)
The center point passage line (61) passing through
Inclining with respect to the axis line (62) of (58), the inter-valve port portion (63) located between the center points (59) and (60) is parallel to the center point passing line (61). The auxiliary combustion chamber type diesel engine is characterized in that the direction of the inter-valve port portion (63) is inclined with respect to the direction of the intake introduction port portion (58) by being formed. 6. The sub-combustion chamber type diesel engine according to claim 5, wherein the peripheral wall (64) of the inter-valve port portion (63) is viewed in a direction parallel to the cylinder center axis (3), The virtual transverse line
A sub-combustion chamber type diesel engine, characterized in that an outer portion (65) on the side far from (56) is curved in an outwardly bulging shape. 7. The sub-combustion chamber type diesel engine according to claim 5, wherein the intake introduction port portion (58) is reduced in diameter from a starting end to a terminating end thereof. A sub-combustion chamber type diesel engine characterized by the following.