US4721080A — Structure of combustion chamber in diesel engine

Claim 1

Independent Claim 385 words

A combustion chamber structure in a diesel engine of a direct injection type having a cylinder block (20), a cylinder head (22) disposed above the cylinder block (20), a piston (30) fitted in a cylinder (28) of the cylinder block (20), a combustion chamber (32) which is formed as a recess in a top part (30a) of the piston (30) and whose upper surface is covered with the cylinder head (22), and a fuel injection nozzle (26) disposed in the cylinder head (22) for injecting fuel into the combustion chamber (32), characterized in that the combustion (32) is formed in the shape of a geometrical rotating body; that the combustion chamber (32) has a side wall (32a) and this side wall (32a) comprises a guide wall (34) which becomes larger in inside diameter downwardly from an opening edge portion (33) of the combustion chamber (32), a first fuel reflection wall (36) formed below the guide wall (34) so that it becomes smaller in inside diameter downwardly, a second fuel reflection wall (38) formed below the first fuel reflection wall (36) approximately in parallel with a central axis (lo) of the combustion chamber (32), and a lower side wall (48a) formed below the second fuel reflection wall (38), having a concavely curved shaped at its upper portion and connected at its lower portion to a bottom (32b) of the combustion chamber (32); that the combustion chamber (32) is composed of a first combustion chamber (44) surrounded by the guide wall (34), first fuel reflection wall (36) and second fuel reflection wall (38) and a second combustion chamber (48) formed below the first combustion chamber (44) and surrounded by the lower side wall (48a); and that spout orifices of the injection nozzle (26) are disposed so that in a top dead-center position of the piston (30), the fuel spray from the nozzle (26) is directed to a junction (42) between the first combustion chamber (44) and the second combustion chamber (48) and to the second fuel reflection wall (38) to cause the fuel spray to be reflected by the junction (42) and the second fuel reflection wall (38) into the first and second combustion chambers (44) and (48) so that the fuel spray is mixed with air in the first and second combustion chambers (46) and (48).

Claim 2

Dependent Claim 385 words

A combustion chamber structure in a diesel engine of a direct injection type having a cylinder block (20), a cylinder head (22) disposed above the cylinder block (20), a piston (30) fitted in a cylinder (28) of the cylinder block (20), a combustion chamber (32) which is formed as a recess in a top part (30a) of the piston (30) and whose upper surface is covered with the cylinder head (22), and a fuel injection nozzle (26) disposed in the cylinder head (22) for injecting fuel into the combustion chamber (32), characterized in that the combustion (32) is formed in the shape of a geometrical rotating body; that the combustion chamber (32) has a side wall (32a) and this side wall (32a) comprises a guide wall (34) which becomes larger in inside diameter downwardly from an opening edge portion (33) of the combustion chamber (32), a first fuel reflection wall (36) formed below the guide wall (34) so that it becomes smaller in inside diameter downwardly, a second fuel reflection wall (38) formed below the first fuel reflection wall (36) approximately in parallel with a central axis (lo) of the combustion chamber (32), and a lower side wall (48a) formed below the second fuel reflection wall (38), having a concavely curved shaped at its upper portion and connected at its lower portion to a bottom (32b) of the combustion chamber (32); that the combustion chamber (32) is composed of a first combustion chamber (44) surrounded by the guide wall (34), first fuel reflection wall (36) and second fuel reflection wall (38) and a second combustion chamber (48) formed below the first combustion chamber (44) and surrounded by the lower side wall (48a); and that spout orifices of the injection nozzle (26) are disposed so that in a top dead-center position of the piston (30), the fuel spray from the nozzle (26) is directed to a junction (42) between the first combustion chamber (44) and the second combustion chamber (48) and to the second fuel reflection wall (38) to cause the fuel spray to be reflected by the junction (42) and the second fuel reflection wall (38) into the first and second combustion chambers (44) and (48) so that the fuel spray is mixed with air in the first and second combustion chambers (46) and (48).

Claim 3

Dependent Claim 29 words

A combustion chamber structure in a diesel engine as set forth in claim 1, wherein the displacement per cylinder of the diesel engine is 300 cc to 800 cc.

Claim 4

Dependent Claim 32 words

A combustion chamber structure in a diesel engine as set forth in claim 1, wherein the second fuel reflection wall (38) is in the shape of a side face of a column.

Claim 5

Dependent Claim 46 words

A combustion chamber structure in a diesel engine as set forth in claim 1, wherein an upper portion of the lower side wall (48a) is in the shape of an arc in a longitudinal section through the central axis (lo) of the second combustion chamber (48).

Claim 6

Dependent Claim 25 words

A combustion chamber structure in a diesel engine as set forth in claim 1, wherein the junction (42) is in the shape of an edge.

Claim 7

Dependent Claim 111 words

A combustion chamber structure in a diesel engine as set forth in claim 1, wherein a diameter D 1 of the opening edge portion (33) of the first combustion chamber (32), a diameter D 2 of a first connection (50) between the guide wall (34) and the first fuel reflection wall (36), a diameter D 3 of the junction (42) and a maximum diameter D 4 of the second combustion chamber (48), are in the following relationship: D.sub.1 ≦D.sub.3 ≦D.sub.2 ≦D.sub.4 and wherein the ratio H/D 4 of the depth H of the combustion chamber (32) to the maximum diameter D 4 of the second combustion chamber (48) is: 0.3≦H/D.sub.4 ≦0.5.

Claim 8

Dependent Claim 42 words

A combustion chamber structure in a diesel engine as set forth in claim 1, wherein the distance r between a central position of the first combustion chamber (44) and the center of the fuel injection nozzle (26) is set at r≦2.5 mm.

Claim 9

Dependent Claim 79 words

A combustion chamber structure in a diesel engine as set forth in claim 1, wherein the upper opening edge portion (33) of the guide wall (34) and a first connection (50) between the guide wall (34) and the first fuel reflection wall (36) are formed as arcs of the following radii R 1 and R 2 in a longitudinal section through the central axis (lo) of the first combustion chamber (44): 0.3 mm≦R.sub.1 ≦1.0 mm, 0.3 mm≦R.sub.2 ≦1.0 mm.

Claim 10

Dependent Claim 31 words

A combustion chamber structure in a diesel engine as set forth in claim 1, wherein the guide wall (34) is in the shape of a side face of a truncated cone.

Claim 11

Dependent Claim 36 words

A combustion chamber structure in a diesel engine as set forth in claim 9, wherein the angle α between the guide wall (34) and the central axis (lo) of the first combustion chamber (44) is 15°≧α≧45°.

Claim 12

Dependent Claim 33 words

A combustion chamber structure in a diesel engine as set forth in claim 1, wherein the first fuel reflection wall (36) is in the shape of a side face of a truncated cone.

Claim 13

Dependent Claim 38 words

A combustion chamber structure in a diesel engine as set forth in claim 11, wherein the angle β between the first fuel reflection wall (36) and the central axis (lo) of the first combustion chamber (44) is 15°≧β≧45°.

Claim 14

Dependent Claim 242 words

A diesel engine of the direct injection type comprising: means defining at least one cylinder having a cylinder head thereon and an inlet portion for introducing air therein; a piston mounted to undergo reciprocatory movement within the cylinder and having a cavity therein defined by an inner wall of the piston, the inner wall having a top edge section facing the cylinder head to define the opening of the cavity, a bottom section opposing the cylinder head to define the bottom of the cavity, an upper section extending downwardly from the top edge section and tapering radially outwardly to define an upper combustion chamber in the cavity, a lower section extending upwardly from the bottom section and curving radially outwardly to define a lower combustion chamber in the cavity, and an intermediate section extending between the upper and lower sections and protruding radially inwardly to divide the upper and lower combustion chambers, the radial innermost portion of the intermediate section being substantially parallel to the axis of the piston to define a reflection wall; and means including an injection nozzle disposed on the inside of the cylinder head for directing a fuel spray against the reflection wall when the piston moves to top-dead-center position to cause the fuel spray to be reflected by the reflection wall and directed therefrom as separate fuel sprays into the upper and lower combustion chambers, respectively, for mixture with air in the upper and lower combustion chambers.

Claim 15

Dependent Claim 242 words

A diesel engine of the direct injection type comprising: means defining at least one cylinder having a cylinder head thereon and an inlet portion for introducing air therein; a piston mounted to undergo reciprocatory movement within the cylinder and having a cavity therein defined by an inner wall of the piston, the inner wall having a top edge section facing the cylinder head to define the opening of the cavity, a bottom section opposing the cylinder head to define the bottom of the cavity, an upper section extending downwardly from the top edge section and tapering radially outwardly to define an upper combustion chamber in the cavity, a lower section extending upwardly from the bottom section and curving radially outwardly to define a lower combustion chamber in the cavity, and an intermediate section extending between the upper and lower sections and protruding radially inwardly to divide the upper and lower combustion chambers, the radial innermost portion of the intermediate section being substantially parallel to the axis of the piston to define a reflection wall; and means including an injection nozzle disposed on the inside of the cylinder head for directing a fuel spray against the reflection wall when the piston moves to top-dead-center position to cause the fuel spray to be reflected by the reflection wall and directed therefrom as separate fuel sprays into the upper and lower combustion chambers, respectively, for mixture with air in the upper and lower combustion chambers.

Claim 16

Dependent Claim 19 words

A diesel engine as set forth in claim 13; wherein the lower section has the shape of an arc.

Claim 17

Dependent Claim 19 words

A diesel engine as set forth in claim 13; wherein the intermediate section has the shape of a column.

Claim 18

Dependent Claim 24 words

A diesel engine as set forth in claim 13; wherein the displacement per cylinder of the diesel engine is 300 cc to 800 cc.

Claim 19

Dependent Claim 32 words

A diesel engine as set forth in claim 13; wherein the top edge section has the shape of an arc having a radius in the range of 0.3 mm to 1.0 mm.

Claim 20

Dependent Claim 31 words

A diesel engine as set forth in claim 13; wherein the injection nozzle protrudes downwardly from the cylinder head at a distance in the range of 2.0 mm to 3.5 mm.

Claim 21

Dependent Claim 28 words

A diesel engine as set forth in claim 13; wherein the intermediate section comprises a plurality of intermediate segments connected in series along the circumference of the cavity.

Claim 22

Dependent Claim 23 words

A diesel engine as set forth in claim 19; wherein the intermediate segments are inclined with respect to the bottom of the cavity.

Claim 23

Dependent Claim 21 words

A diesel engine as set forth in claim 20; wherein the adjacent intermediate segments are oppositely inclined relative to each other.

Claim 24

Dependent Claim 35 words

A diesel engine as set forth in claim 13; including control means for controlling the injection of the fuel spray injected by the injection nozzle in accordance with the load condition of the diesel engine.

Claim 25

Dependent Claim 48 words

A diesel engine as set forth in claim 22; wherein the control means includes means operative under relatively low load conditions to enable the injection nozzle to direct the fuel spray only along a lower portion of the reflection wall immediately after the piston reaches the top-dead-center position.

Claim 26

Dependent Claim 51 words

A diesel engine as set forth in claim 22; wherein the control means includes means operative under relatively medium load conditions to enable the injection nozzle to direct the fuel spray along substantially the entire portion of the reflection wall during the initial movement of the piston from the top-dead-center position.

Claim 27

Dependent Claim 53 words

A diesel engine as set forth in claim 22; wherein the control means includes means operative under relatively high load conditions to enable the injection nozzle to direct the fuel spray along the first-mentioned reflection wall and the other reflection wall adjacent thereto during the movement of the piston from the top-dead-center position.

Claim 28

Dependent Claim 23 words

A diesel engine as set forth in claim 13; wherein the cavity of the piston has the shape of a geometrical rotating body.

Claim 29

Dependent Claim 26 words

A diesel engine as set forth in claim 26; wherein the axis of the geometrical rotating body is deviated from the axis of the cylindrical piston.

Claim 30

Dependent Claim 28 words

A diesel engine as set forth in claim 26; wherein the injection nozzle is located at a distance less than 2.5 mm from the axis of the cavity.

Claim 31

Dependent Claim 75 words

A diesel engine as set forth in claim 26; wherein the top edge section has a diameter D 1 , the upper section has a maximum diameter D 2 , the intermediate section has a diameter D 3 , and the lower section has a maximum diameter D 4 satisfying the relation D 1 ≦D 3 ≦D 2 ≦D 4 , and the cavity has a depth H in the range of 0.3≦H/D 4 ≦0.5.

Claim 32

Dependent Claim 24 words

A diesel engine as set forth in claim 29; wherein the piston has an outer diameter B in the range of 0.4≦D 4 /B≦0.6.

Claim 33

Dependent Claim 33 words

A diesel engine as set forth in claim 13; wherein the inner wall comprises a plurality of vertical sections divided transversely from each other and extending upwardly from the bottom of the cavity.

Claim 34

Dependent Claim 32 words

A diesel engine as set forth in claim 31; wherein the inner wall comprises a certain number of the vertical sections corresponding to a number of spout orifices of the injection nozzle.

Claim 35

Dependent Claim 23 words

A diesel engine as set forth in claim 31; wherein the vertical sections comprise a segment surface of different geometrically coaxially rotating bodies.

Claim 36

Dependent Claim 22 words

A diesel engine as set forth in claim 33; wherein the vertical sections are disposed equi-angular-distantly around the axis of the cavity.

Claim 37

Dependent Claim 30 words

A diesel engine as set forth in claim 31; wherein the adjacent vertical sections have segmented intermediate sections respectively disposed at different depths from the top opening of the cavity.

Claim 38

Dependent Claim 19 words

A diesel engine as set forth in claim 35; including transition sections for continuously connecting the segmented intermediate sections.

Claim 39

Dependent Claim 56 words

A diesel engine as set forth in claim 13; wherein the upper section comprises an upper sub-section extending downwardly and radially outwardly from the top edge section to define a guide wall, and a lower sub-section extending upwardly and radially outwardly from the intermediate section to define another reflection wall contiguous to the first-mentioned reflection wall.

Claim 40

Dependent Claim 47 words

A diesel engine as set forth in claim 37; wherein said another reflection wall is shaped so that the fuel spray which impinges thereon and is reflected thereby into the upper and lower combustion chambers when the piston moves away from the vicinity of the cylinder head.

Claim 41

Dependent Claim 29 words

A diesel engine as set forth in claim 37; wherein the guide wall is shaped to restrict the flow of the reflected fuel spray within the upper combustion chambers.

Claim 42

Dependent Claim 40 words

A diesel engine as set forth in claim 37; including a border section dividing the upper and lower sub-sections, the border section having the shape of an arc having a radius in the range of 0.3 mm to 1.0 mm.

Claim 43

Dependent Claim 20 words

A diesel engine as set forth in claim 37; wherein the upper sub-section has the shape of a truncated cone.

Claim 44

Dependent Claim 28 words

A diesel engine as set forth in claim 41; wherein the upper sub-section has an inclination of 15° to 45° relative to the longitudinal axis of the piston.

Claim 45

Dependent Claim 20 words

A diesel engine as set forth in claim 37; wherein the lower sub-section has the shape of a truncated cone.

Claim 46

Dependent Claim 28 words

A diesel engine as set forth in claim 43; wherein the lower sub-section has an inclination of 15° to 45° relative to the longitudinal axis of the piston.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1991-01-25	1991-07-27	1992-01-26	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1995-01-25	1995-07-27	1996-01-26	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1999-01-25	1999-07-27	2000-01-26	$7700.00	Window Closed / Lapsed

Structure of combustion chamber in diesel engine

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