JPH0711957A - Auxiliary chamber type diesel engine - Google Patents

Abstract

PURPOSE:To perform effective mixture of air and combustion expansion gas in each valve recess by a method wherein a pair of valve recesses are formed on the top surface of a piston and distributed to both sides of the injection axis of a jet nozzle, and the revolving center of each revolving gas flow is arranged in each valve recess. CONSTITUTION:An injection nozzle 4 is disposed at a cylinder head 23 formed at an auxiliary chamber 1 and in a position situated eccentrically from a cylinder central line 3 in a state to point to the central part of a cylinder 22 in which a main combustion chamber 5 is formed. In which case, combustion expansion gas injected through the injection nozzle 4 causes the generation of a linear advancing gas flow 27 along the injection axis 12 of the injection nozzle 4 and a pair of revolving gas flows 6 and 7 positioned on both sides of the injection axis 12. In this case, at least a pair of valve recesses 10 and 11 are formed at least one of a cylinder head surface 9 fronting on the main combustion chamber 5 and a piston top surface 8 and distributed to both sides of the injection axis 12. The revolving centers 14 and 15 of the revolving gas flows 6 and 7 are positioned in the valve recesses 10 and 11, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sub-combustion chamber type diesel engine, and more particularly, to a sub-combustion chamber type diesel engine capable of effectively mixing air in a valve recess 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 this injection port is directed toward the cylinder center axis line. As an engine of this type, there is an engine in which a pair of valve recesses are provided on the top surface of a piston.

[0003]

In the engine with the valve recess described above, when the piston is near the top dead center, the volume ratio of the valve recess to the total volume of the main combustion chamber becomes relatively large. It was expected that a large amount of air that was collected as a result would effectively mix with the combustion expansion gas that was injected from the nozzles to improve combustion performance. However, in reality, the combustion performance is not so much improved as compared with an engine without a valve recess. It is considered that the reason is that the air in the valve recess and the combustion expansion gas are not mixed effectively.

An object of the present invention is to effectively mix the air in the valve recess and the combustion expansion gas in the auxiliary combustion chamber type diesel engine.

[0005]

As described below, the present invention locates the swirl center of the swirl gas flow inside the valve recess. However, in the past, what kind of combustion expansion gas injected from the injection port in the main combustion chamber was used? Since it was not confirmed whether the fluidized state was exhibited, there was 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 cylinder center axis, the inventors form a straight flow along the injection axis of the injection port and a pair of swirling flows located on both sides of the injection axis. It was confirmed. And
Based on this knowledge, the inventors presumed that, when the engine was actually operated, the combustion expansion gas ejected from the injection port 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. Further, in the engine of the same individual, the position of each swirling center of the pair of swirling gas flows 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 existing engine with a valve recess, the positional relationship between the valve recess and the swirling gas flow was examined, and it was also confirmed that the swirling center of the swirling gas flow was off the valve recess when viewed in a direction parallel to the cylinder center axis.

As a result, the inventors have found that when the swirl center of the swirling gas flow is located in the valve recess when viewed in a direction parallel to the cylinder center axis, the air in the valve recess and the swirling gas flow are effectively mixed. It was estimated that the combustion performance would be greatly improved, and the present invention was achieved.

[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,
The injection port 4 was directed toward the center of the cylinder 22. According to such a configuration, when viewed in a direction parallel to the cylinder center axis line 3, the combustion expansion gas injected from the injection port 4 has a straight gas flow 27 along the injection axis line 12 of the injection port 4 and the injection axis line 12.
It was confirmed by the inventors of the present invention to form a pair of swirling gas flows 6 and 7 located on both sides of the.

Therefore, at least one of the cylinder head surface 9 and the piston top surface 8 facing the main combustion chamber 5 is
At least a pair of valve recesses 10 and 11 are provided in a concave shape, and the pair of valve recesses 10 and 11 are distributed on both sides of the injection axis 12 of the injection port 4 when viewed in a direction parallel to the cylinder center axis 3.

Then, as illustrated in FIGS. 1 to 14,
When viewed in a direction parallel to the cylinder center axis 3, the pair of swirling gas flows 6 and 7 are disposed in the pair of valve recesses 10 and 11.
The respective turning centers 14 and 15 of the above are positioned.

(Second Invention) As shown in FIG. 1, the second invention is characterized in that a total of three intake valves 32 and 33 and exhaust valves 35 are provided in the first invention.

(Third Invention) As shown in FIGS. 1 and 5 to 11, the third invention is the same as the first invention or the second invention, except that the gas passage groove 40 is recessed in the piston top surface 8. When viewed in a direction parallel to the cylinder center axis line 3, the starting end portion 41 of the gas passage groove 40 is formed at a position overlapping the injection port 4, and from this starting end portion 41, at least the pair of valve recesses 10 and 11 is formed. Of these, the gas passage groove 40 is formed over the portions 42 and 43 near the injection axis 12.

(Fourth Invention) As shown in FIGS. 5 and 9, the fourth invention is, in the third invention, at least one of the cylinder head surface 9 and the piston top surface 8 facing the main combustion chamber 5. A ridge 66 is provided in the cylinder, and the ridge 66 is located between the pair of valve recesses 10 and 11 on the injection axis 12 of the injection port 4 when viewed in a direction parallel to the cylinder center axis 3. And

(Fifth Invention) As shown in FIG. 6, FIG. 7, FIG. 10, and FIG. 11, the fifth invention is different from the third invention or the fourth invention in that the piston top surface 8 is different. A recessed valve recess 37, and the valve recess 37 is farther from the injection port 4 than the pair of valve recesses 10 and 11.
A straight gas flow deflecting groove 48 is led out from an end portion 52 of the gas passage groove 40, and the straight gas flow deflecting groove 48 is tangentially connected to the other valve recess 37.

(Sixth Invention) As shown in FIG. 3, a sixth invention is any one of the first to fifth inventions, and 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 essentially in parallel with the virtual transverse line 56, and the center point 59 of the intermediate intake valve port 30 with respect to the virtual transverse line 56. Are arranged closer to each other than the center point 60 of the terminal intake valve port 31.
The center point passage line 61 passing through
The axis 62 was tilted.

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.

(Seventh Invention) As shown in FIG. 3, a seventh invention is the same as the sixth invention, except that the inter-valve-port port portion 63 is provided.
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.

(Eighth Invention) As shown in FIG. 3, an eighth invention is the invention of either the sixth invention or the seventh 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 or Second Invention) As illustrated in FIG. 1A, the air in the pair of valve recesses 10 and 11 is surrounded by the swirling gas flows 6 and 7 from the surroundings, and is dragged by the swirling gas flows 6 and 7 to swirl. It swirls in the same direction as the gas 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 combustion performance is enhanced, and thereby the output performance is enhanced, and the emission amount of the unburned harmful component in the exhaust gas is reduced.

(Third Invention) As shown in FIGS. 1 and 5 to 11, the combustion expansion gas ejected from the injection port 4 passes through the gas passage groove 40 with a small resistance, so that a pair of left and right swirling gas flows 6 is formed.・ The flow velocity of 7 increases, and a pair of valve recesses 10 ・
The mixing of the air in 11 and the combustion expansion gas is further promoted.

(Fourth Invention) As illustrated in FIGS. 5 and 9, a part of the straight gas flow 27 is deflected to the left and right by the resistance of the edge portion 46 of the raised portion 66, and the swirling gas flows 6 and 7 are changed. The flow velocity is increased, and the mixing of the air in the pair of left and right valve recesses 10 and 11 with the swirling gas flow 6 and 7 is further promoted.

(Fifth Invention) FIG. 6, FIG. 7, FIG. 10, FIG.
, The straight gas flow 27 is deflected through the straight gas flow deflection groove 48 and introduced tangentially to the other valve recess 37, where a new swirl gas flow 49 is formed.
Air accumulated in other valve recess 37 and straight gas flow 2
Mixing with 7 is further promoted.

(Sixth Invention) As illustrated in FIG. 3, 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 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 turbulent flow near the terminal intake valve opening 31 that becomes an intake resistance is generated. This prevents the intake air from being charged with high efficiency.

(Seventh Invention) As illustrated in FIG. 3, since the intake air 67 guided by the outer portion 65 is smoothly guided by the curve thereof, the guide resistance of the intake air 67 can be reduced, and this outward movement As compared with the case where the portion 65 is formed straight, the charging efficiency of the intake air is maintained higher.

(Eighth Invention) As illustrated in FIG. 3, the flow velocity of the intake air flowing from the intake port introduction 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 swirl speed in the cylinder 22 is increased.

[0031]

Embodiments of the present invention will be described with reference to the drawings.
First, a first embodiment will be described based on FIGS. 1 to 3.
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 forms a straight gas flow 27 along the injection axis 12 of the injection port 4 and a pair of swirling gas flows 6 and 7 located on both sides of the injection axis 12 of the injection port 4.
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.

As shown in FIGS. 1 (B) and 1 (C),
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 respective turning centers 14 and 15 are located. The recess centers 16 and 17 and the swivel centers 14 and 15 may essentially coincide with 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 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.

Further, a fan-shaped gas passage groove 40 is provided on the top surface 8 of the piston. The gas passage groove 40, when viewed in a direction parallel to the cylinder center axis 3, has its starting end portion 41.
Is formed at a position overlapping the injection port 4, and as the distance from the start end portion 41 along the injection axis 12 of the injection port 4 is increased, the width thereof is gradually widened and the depth thereof is gradually reduced. ing. The left and right portions of the gas passage groove 40 are formed by a pair of left and right valve recesses 10.
11, the portions 42 and 43 near the injection axis 12 overlap, and the central end portion of the gas passage groove 40 overlaps the portion 44 near the imaginary transverse line 13 in the front valve recess 37.

According to this structure, the combustion expansion gas ejected from the injection port 4 passes through the gas passage groove 40 with little resistance, so that the flow velocity of the pair of left and right swirling gas flows 6 and 7 and the straight gas flow 27 is increased. , All valve recesses 10/11/37
The mixing of the air inside and the combustion expansion gas is further promoted.

Next, the structure of the cylinder head of the first embodiment will be described in detail. As shown in FIG. 3A, 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, the cylinder 22 is 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 59 of the intermediate intake valve opening 30 is located closer to the second virtual transverse line 5 than the center point 60 of the terminal intake valve opening 31.
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 this structure, the intake air 67 passing through the inter-valve port portion 63 tries to proceed straight by the 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 intake charging efficiency is kept high.

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 central 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 intake charging efficiency is maintained higher.

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 swirl speed in the cylinder 22 is 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 °.

4 to 14 show the second to twelfth embodiments.
Embodiments have been shown, and in each of these embodiments, the same elements as those in the first embodiment will be described with the same reference numerals in the drawings. Further, regarding these second to twelfth embodiments, the elements not particularly shown in the drawings and the following text have the same structure as the first embodiment unless it goes against the essence of the present invention.

The second embodiment shown in FIG. 4 corresponds to the first embodiment shown in FIG.
In the modification of the embodiment, a pair of left and right valve recesses 10 and 11 are provided.
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 third embodiment shown in FIG. 5 is the first embodiment shown in FIG.
In the modification of the embodiment, a ridge 66 is added to the piston top surface 8. The raised portion 66 is located between the pair of left and right valve recesses 10 and 11 on the injection axis 12 of the injection port 4 when viewed in a direction parallel to the cylinder center axis 3, and is raised from the inner bottom surface 45 of the gas passage groove 40. ing. The edge portion 46 of the raised portion 66 facing the injection port 4 side is formed in an arc shape when viewed in a direction parallel to the cylinder axis 3, and rises from the inner bottom surface 45 of the gas passage groove 40. The gas passage groove 40 is bifurcated by the rising edge 46. The upper surface 47 of the raised portion 66 is formed in an upwardly sloped shape and has a stepped shape with respect to the inner bottom surface 45 of the gas passage groove 40.

With this structure, the resistance of the edge portion 46 of the raised portion 66 deflects a part of the straight gas flow 27 to the left and right, and the flow velocity of the swirling gas flows 6 and 7 is increased. Air in 10/11 and swirling gas flow 6.7
The mixing with is further promoted.

The fourth embodiment shown in FIG. 6 corresponds to the first embodiment shown in FIG.
In a modification of the embodiment, the gas passage groove 40 is formed to be short, and the straight gas flow deflection groove 48 is led out from the end portion 52 thereof and is tangentially connected to the valve recess 37 on the front side. According to such a configuration, the straight gas flow 27 is deflected through the straight gas flow deflection groove 48 and is tangentially introduced into the front valve recess 37, where a new swirl gas flow 49 is formed.
Is formed, and the mixing of the air accumulated in the valve recess 37 on the front side with the straight gas flow 27 is further promoted.

The fifth embodiment shown in FIG. 7 is the fourth embodiment shown in FIG.
This is a modification of the embodiment and is intended for application to a four-valve engine. That is, a pair of front-side valve recesses 37 are provided on the piston top surface 8, and the end portion 52 of the gas guide groove 40 is provided.
From this, two straight gas flow deflection grooves 48, 48 are led out, and these are tangentially connected to the front two valve recesses 37, 37.

The sixth embodiment shown in FIG. 8 is a modification of the first embodiment shown in FIG. 1, in which the shape of the gas guide groove 40 is changed to a rectangular shape. The gas passage groove 40 is formed so that its depth becomes gradually shallower as it goes away from the injection port 4 along the injection axis 12 of the injection port 4 from its start end portion 41. The left and right portions of the gas passage groove 40 communicate with the respective portions 42 and 43 of the pair of left and right valve recesses 10 and 11 near the injection axis 12.

The seventh embodiment shown in FIG. 9 is a modification of the sixth embodiment shown in FIG. 8 and is similar to the third embodiment shown in FIG.
6 has been added.

The eighth embodiment shown in FIG. 10 is a modification of the sixth embodiment shown in FIG. 8, in which the straight gas flow deflection groove 48 is led out from the terminal end portion 52 of the gas passage groove 40, and the straight gas flow deflection groove 48 is provided on the front side. It is tangentially connected to 37.

The ninth embodiment shown in FIG. 11 is a modification of the eighth embodiment shown in FIG. 10 and is intended for application to a four-valve engine. That is, a pair of front side valve recesses 37 are provided on the piston top surface 8, two straight gas flow deflection grooves 48, 48 are led out from the terminal end portion 52 of the gas passage groove 40, and these two front side valve recesses 37 ,. It is connected to 37 tangentially.

The tenth embodiment shown in FIG. 12 is a modification of the first embodiment shown in FIG. 1 in which the gas passage groove 40 is eliminated. Even if the gas passage groove 40 is not provided as in the tenth embodiment and the eleventh and twelfth embodiments described below, the swirl centers 14 of the pair of swirl gas flows 6 and 7 are not provided.
15 occurs at essentially the same position as when there is the gas passage groove 40.

An eleventh embodiment shown in FIG. 13 is a modification of the tenth embodiment shown in FIG. 12, and relates to a two-valve engine, in which only a pair of valve recesses 10 and 11 are formed on the piston top surface 8. .

The twelfth embodiment shown in FIG. 14 is a modification of the tenth embodiment shown in FIG. 12 and is intended for application to a four-valve engine. That is, the front valve recess 37
Are left and right, and the valve recesses 37
The respective recess centers 38, 38 are arranged at positions symmetrical with respect to the respective recess centers 16, 17 of the valve recesses 10, 11 near the injection port 4 with the virtual transverse line 13 as a boundary.
According to such a configuration, the straight gas flow 27 is applied to the cylinder 2
2 collides with the inner peripheral surface of 2 and is reversed, and the front valve recess 37
The new swirling gas flows 39, 39 flow into 37, and the air in each valve recess 37, 37 and the straight gas flow 27 are also reliably mixed.

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. The pair of left and right valve recesses 10 and 11 may be formed not only on one of the cylinder head surface 9 and the piston top surface 8 facing the main combustion chamber 5, but also on both of them.

The structure of the intake port 28 of the first embodiment described with reference to FIG. 3 can be applied to other embodiments as long as it does not violate its essence.

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 toward 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 are substantially coincident with each other so that the swirling gas flows 6 and 7 are generated at positions away from the injection port 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 are seen in a direction parallel to the cylinder center axis 3, and the recess centers 16 of the pair of valve recesses 10 and 11 are seen.
It is not limited to the case where it is located above 17 and it may be located inside the pair of valve recesses 10 and 11. 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. It is desirable to locate the swivel centers 14 and 15 in respective regions surrounded by virtual circles having a radius of 2/3 of the radius of the valve recesses 10 and 11 with the recess centers 16 and 17 as the centers.

Further, 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.

Further, 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 feature is that 15 is located in the pair of valve recesses 10 and 11. That is, each embodiment
The structure is not such that the flow of the combustion expansion gas is forcibly deflected toward the pair of valve recesses by the 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. As described above, the pair of swirling gas flows 6 and 7
From the fact that the swirl centers 14 and 15 can be located at substantially the same position with or without the gas passage groove 40, the gas passage groove 40 allows the combustion expansion gas to form a pair of valve recesses 10. It is understood that it is not forcibly biased towards 11.

[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 schematic view of a nozzle used in the first embodiment of the present invention,
FIG. 2 (A) is a perspective view of the nozzle seen from the side, and FIG. 2 (B).
[Fig. 3] is a perspective view of a nozzle seen from the front side.

3A and 3B are views for explaining a cylinder head used in the first embodiment of the present invention, FIG. 3A is a cross-sectional plan view, and FIG. 3B is a sectional view taken along line BB of FIG. 3A. is there.

FIG. 4 is a vertical sectional view of a cylinder head used in a second embodiment of the present invention.

5A and 5B are views for explaining a piston used in the third embodiment of the present invention, FIG. 5A is a plan view of the piston, FIG. 5B is a sectional view taken along line BB of FIG. 5A, FIG. 5C is FIG. 5A.
5 is a sectional view taken along the line CC of FIG. 5, and FIG. 5D is a sectional view taken along the line DD of FIG.

6A and 6B are views for explaining a piston used in a fourth embodiment of the present invention, FIG. 6A is a plan view of the piston, FIG. 6B is a sectional view taken along line BB of FIG. 6A, FIG. 6C is FIG. 6A.
6 is a sectional view taken along line C-C of FIG. 6, and FIG. 6D is a sectional view taken along line DD of FIG.

7A and 7B are views for explaining a piston used in a fifth embodiment of the present invention, FIG. 7A is a plan view of the piston, FIG. 7B is a sectional view taken along line BB of FIG. 7A, FIG. 7C is FIG. 7A.
7 is a sectional view taken along line C-C of FIG. 7, and FIG. 7D is a sectional view taken along line DD of FIG. 7A.

8A and 8B are views for explaining a piston used in a sixth embodiment of the present invention, FIG. 8A is a plan view of the piston, FIG. 8B is a sectional view taken along line BB of FIG. 8A, FIG. 8C is FIG. 8A.
6 is a cross-sectional view taken along the line CC of FIG.

9A and 9B are views for explaining a piston used in a seventh embodiment of the present invention, FIG. 9A is a plan view of the piston, FIG. 9B is a sectional view taken along line BB of FIG. 9A, FIG. 9C is FIG. 9A.
9 is a sectional view taken along the line CC of FIG. 9, and FIG. 9D is a sectional view taken along the line DD of FIG.

FIG. 10 is a diagram illustrating a piston used in an eighth embodiment of the present invention, FIG. 10 (A) is a plan view of the piston, and FIG.
10B is a sectional view taken along line BB of FIG. 10A, and FIG.
Is a cross-sectional view taken along the line CC of FIG. 10A, and FIG.
It is the DD sectional view taken on the line 0 (A).

FIG. 11 is a view for explaining a piston used in a ninth embodiment of the present invention, FIG. 11 (A) is a plan view of the piston, and FIG.
11B is a sectional view taken along line BB of FIG. 11A, FIG.
11A is a sectional view taken along line CC of FIG. 11A, and FIG.
It is the DD sectional view taken on the line of 1 (A).

FIG. 12 is a plan view of a piston used in a tenth embodiment of the present invention.

FIG. 13 is a plan view of a piston used in an eleventh embodiment of the present invention.

FIG. 14 is a plan view of a piston used in a twelfth embodiment of the present invention.

[Explanation of symbols]

1 ... Secondary combustion chamber, 3 ... Cylinder center axis line, 4 ... Injection port, 5 ...
Main combustion chamber, 6 ・ 7 ... left and right 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 turning center, 16 ・ 17 ... 10/11 recess center, 22 ... Cylinder, 23 ... Cylinder head, 28 ... Intake port, 30 ... Intermediate intake valve port, 31 ... Terminal intake valve port,
32.33 ... intake valve, 35 ... exhaust valve, 37 ... (on front side)
Valve recess, 40 ... Gas passage groove, 41 ... 40 start end, 42.43 ... 10/11 part closer to 12, 48 ...
Straight gas flow deflection groove, end portion of 52 ... 40, 54 ... (front side) area, 56 ... (second) virtual transverse line, 57 ... (rear side) area, 58 ... Intake introduction 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, 66 ... raised portion.

Claims (8)

[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 nozzle (4) has a straight gas flow (27) along the injection axis (12) of the nozzle (4) and the injection axis (12). A sub-combustion chamber type diesel engine which forms a pair of swirling gas flows (6) and (7) located on both sides of the cylinder head surface (9) facing the main combustion chamber (5). ) And the piston top surface (8), at least one of the valve recesses (10) and (11) is provided on at least one of the recesses, and when viewed in a direction parallel to 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. 2. The auxiliary combustion chamber type diesel engine according to claim 1, wherein intake valves (32), (33) and an exhaust valve are provided.
A sub-combustion chamber type diesel engine, which is equipped with a total of three (35). 3. The auxiliary combustion chamber type diesel engine according to claim 1 or 2, wherein a gas passage groove (40) is provided in the piston top surface (8), and a cylinder central axis ( This gas passage groove when viewed in a direction parallel to 3)
A starting end portion (41) of (40) is formed at a position overlapping the injection port (4), and from this starting end portion (41), at least each of the pair of valve recesses (10) and (11) is provided with an injection axis (12). ) The gas passage groove (4)
0) is formed, the sub-combustion chamber type diesel engine characterized by the above. 4. The auxiliary combustion chamber type diesel engine according to claim 3, wherein at least one of the cylinder head surface (9) and the piston top surface (8) facing the main combustion chamber (5) has a raised portion ( 66) is provided, and when viewed in a direction parallel to the cylinder center axis (3),
On the injection axis (12) of (4), the pair of valve recesses
A sub-combustion chamber type diesel engine characterized in that the raised portion (66) is located between (10) and (11). 5. The auxiliary combustion chamber type diesel engine according to claim 3, wherein the piston top surface (8) is provided with another valve recess (37),
This valve recess (37) is replaced by the pair of valve recesses (1
0) and (11) farther from the injection port (4), the straight gas flow deflection groove (48) is led out from the end portion (52) of the gas passage groove (40), and the straight gas flow deflection groove (48) To
A sub-combustion chamber type diesel engine, which is tangentially communicated with the other valve recess (37). 6. The auxiliary combustion chamber type diesel engine according to claim 1, wherein the 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 in parallel with the virtual transverse line (56), and the center point (59) of the intermediate intake valve opening (30) is the center of the terminal intake valve opening (31) with respect to the virtual transverse line (56). By placing them closer than the point (60), 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. 7. The sub-combustion chamber type diesel engine according to claim 6, 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. 8. The auxiliary combustion chamber type diesel engine according to claim 6 or 7, 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.