A four-cycle twelve cylinder engine

Claim 2

A four cycle, 12-cylinder engine including four cylinder groups each having three cylinders (1) located adjacent to each other, the cylinders in each cylinder group having intake strokes spaced apart one from another by 240° in terms of angle of rotation of the engine crankshaft (30), the cylinders in each cylinder group being connected through respective branch intake passages (9) with a common intake passage (7), means (5) being provided for separating the common intake passage of one cylinder group from the common intake passage of another cylinder group.

Claim 3

A four cycle, 12-cylinder engine including six cylinders (1a,e,c,g,i,k) arranged in a first row and six cylinders (1b,d,f,h,j,l) arranged in a second row, said cylinders of said first row and said cylinders of said second row having a common crankshaft (30) to provide a V-­shaped cylinder arrangement, a first cylinder group comprising three cylinders (1a,c,e) from one end of said first row, a second cylinder group comprising the remaining three cylinders (1g,i,k) in said first row, a third cylinder group comprising three cylinders (1b,d,f) from one end of said second row, a fourth cylinder group comprising the remaining three cylinders (1h,j,l) in said second row, said cylinders in each group having intake stroke timings of 240° spacing in terms of angle of rotation of said crankshaft, a first common intake passage means (7a) connected through first branch intake passages (9a,c,e) with respective ones of said cylinders in said first group, a second common intake passage means (7b) connected through second branch intake passages (9g,i,k) with respective ones of said cylinders in said second group, a third common intake passage means (7c) connected through third branch intake passages (9b,d,f) with respective ones of said cylinders in said third group, a fourth common intake passage means (7d) connected through fourth branch intake passages (9h,j,l) with respective ones of said cylinders in said fourth group, said first and second common intake passage means (7a,7b) being located above said cylinders in said first row, said third and fourth common intake passage means (7c,7d) being located above said cylinders in said second row.

Claim 4

A four cycle, 12-cylinder engine including six cylinders (1a,e,c,g,i,k) arranged in a first row and six cylinders (1b,d,f,h,j,l) arranged in a second row, said cylinders of said first row and said cylinders of said second row having a common crankshaft (30) to provide a V-­shaped cylinder arrangement, a first cylinder group comprising three cylinders (1a,c,e) from one end of said first row, a second cylinder group comprising the remaining three cylinders (1g,i,k) in said first row, a third cylinder group comprising three cylinders (1b,d,f) from one end of said second row, a fourth cylinder group comprising the remaining three cylinders (1h,j,l) in said second row, said cylinders in each group having intake stroke timings of 240° spacing in terms of angle of rotation of said crankshaft, a first common intake passage means (7a) connected through first branch intake passages (9a,c,e) with respective ones of said cylinders in said first group, a second common intake passage means (7b) connected through second branch intake passages (9g,i,k) with respective ones of said cylinders in said second group, a third common intake passage means (7c) connected through third branch intake passages (9b,d,f) with respective ones of said cylinders in said third group, a fourth common intake passage means (7d) connected through fourth branch intake passages (9h,j,l) with respective ones of said cylinders in said fourth group, said first and second common intake passage means (7a,7b) being located above said cylinders in said first row, said third and fourth common intake passage means (7c,7d) being located above said cylinders in said second row.

Claim 5

An engine in accordance with claim 2, wherein: said first and second common intake passage means (7a,7b) are longitudinally aligned, a first communicating passage means (19) being provided between said first and second common intake passage means for connecting said first and second common intake passage means with each other, a first shut-off valve means (20) being provided in said first communicating passage means; and said third and fourth common intake passage means (7c,7d) are longitudinally aligned, a second communicating passage means (19) being provided between said third and fourth common intake passage means for connecting said third and fourth common intake passage means with each other, a second shut off valve means (20) being provided in said second communicating passage means.

Claim 6

An engine in accordance with claim 3, wherein: said first and second common intake passage means (7a,7b) are formed integrally and separated from each other by a partition (8); and said second and third common intake passage means (7c,7d) are formed integrally and separated from each other by a partition (8).

Claim 7

An engine in accordance with claim 4, wherein: said first and second branch intake passages (9) extend from said respective common intake passages and towards said second row of cylinders, and bend downward midway between said first and second rows of said cylinders; said third and fourth branch intake passages (9) extend from said respective common intake passages and towards said first row of said cylinders.

Claim 8

An engine in accordance with claim 5, wherein: said first communicating passage means is located below said first and second branch intake passages; and said second communicating passage means is located below said third and fourth branch intake passages.

Claim 9

An engine in accordance with claim 6, wherein: said first and second shut-off valve means each have a shut-off valve fixedly connected to a respective rotatable horizontal shaft (20a).

Claim 10

An engine in accordance with claim 6, wherein: said first and second shut-off valve means each have a shutoff valve fixedly connected to a respective rotatable vertical shaft (20a).

Claim 11

A four cycle, 12-cylinder engine including six cylinders (1a,e,c,g,i,k) arranged in a first row and six cylinders (1b,d,f,h,j,l) arranged in a second row, said cylinders of said first row and said cylinders of said second row having a common crankshaft (30) to provide a V-­shaped cylinder arrangement, a first cylinder group comprising three cylinders (1a,c,e) from one end of said first row, a second cylinder group comprising the remaining three cylinders (1g,i,k) in said first row, a third cylinder group comprising three cylinders (1b,d,f) from one end of said second row, a fourth cylinder group comprising the remaining three cylinders (1h,j,l) in said second row, said cylinders in each group having intake stroke timings of 240° spacing in terms of angle of rotation of said crankshaft, a first common intake passage means (7a) connected through first branch intake passages (9a,c,e) with respective ones of said cylinders in said first group, a second common intake passage means (7b) connected through second branch intake passages (9g,i,k) with respective ones of said cylinders in said second group, a third common intake passage means (7c) connected through third branch intake passages (9b,d,f) with respective ones of said cylinders in said third group, a fourth common intake passage means (7d) connected through fourth branch intake passages (9h,j,l) with respective ones of said cylinders in said fourth group, said first and second common intake passage means (7a,7b) being located above said cylinders in said second row, said third and fourth common intake passage means (7c,7d) being located above said cylinders in said first row.

Claim 12

A four cycle, 12-cylinder engine including six cylinders (1a,e,c,g,i,k) arranged in a first row and six cylinders (1b,d,f,h,j,l) arranged in a second row, said cylinders of said first row and said cylinders of said second row having a common crankshaft (30) to provide a V-­shaped cylinder arrangement, a first cylinder group comprising three cylinders (1a,c,e) from one end of said first row, a second cylinder group comprising the remaining three cylinders (1g,i,k) in said first row, a third cylinder group comprising three cylinders (1b,d,f) from one end of said second row, a fourth cylinder group comprising the remaining three cylinders (1h,j,l) in said second row, said cylinders in each group having intake stroke timings of 240° spacing in terms of angle of rotation of said crankshaft, a first common intake passage means (7a) connected through first branch intake passages (9a,c,e) with respective ones of said cylinders in said first group, a second common intake passage means (7b) connected through second branch intake passages (9g,i,k) with respective ones of said cylinders in said second group, a third common intake passage means (7c) connected through third branch intake passages (9b,d,f) with respective ones of said cylinders in said third group, a fourth common intake passage means (7d) connected through fourth branch intake passages (9h,j,l) with respective ones of said cylinders in said fourth group, said first and second common intake passage means (7a,7b) being located above said cylinders in said second row, said third and fourth common intake passage means (7c,7d) being located above said cylinders in said first row.

Claim 13

An engine in accordance with claim 9, wherein: said first and second common intake passage means (7a,7b) are longitudinally aligned, a first communicating passage means (19) being provided between said first and second common intake passage means for connecting said first and second common intake passage means with each other, a first shut-off valve means (20) being provided in said first communicating passage means and said third and fourth common intake passage means (7c,7d) are longitudinally aligned, a second communicating passage means (19) being provided between said third and fourth common intake passage means for connecting said third and fourth common intake passage means with each other, a second shutoff valve means being provided in said second communicating passage means.

Claim 14

An engine in accordance with claim 10, wherein: said first and second common intake passage means are formed integrally and are separated from each other by a partition (8); and said second and third common intake passage means are formed integrally and separated from each other by a partition (8).

Claim 15

An engine in accordance with claim 11, wherein: said first and second branch intake passages (9) extend from said respective common intake passages and towards said first row of said cylinders, and bend downward midway between said first and said second rows of said cylinders; said third and fourth branch intake passages (9) extend from said respective common intake passages and towards said second row of said cylinders, and bend downward midway between said first and said second rows of said cylinders.

Claim 16

An engine in accordance with claim 12, wherein: said first communicating passage means is defined by a transversely swelled portion of said first and second common intake passages formed adjacent to the partition; and said second communicating passage means is defined by a transversely swelled portion (19) of said third and fourth common intake passages formed adjacent to the partition.

Claim 17

A four cycle, 12-cylinder engine including six cylinders (1a,c,e,g,i,k) arranged in a first row and six cylinders (1b,d,f,h,j,l) arranged in a second row, said cylinders of said first row and said cylinders of said second row having a common crankshaft (30) to provide a V-­shaped cylinder arrangement, a first cylinder group comprising three cylinders (1a,c,e) from one end of said first row, a second cylinder group comprising the remaining three cylinders (1g,i,k) in said first row, a third cylinder group comprising three cylinders (1b,d,f) from one end of said second row, a fourth cylinder group comprising the remaining three cylinders (1h,j,l) in said second row, said cylinders in each group having intake stroke timings of 240° spacing in terms of angle of rotation of said crankshaft, a first common intake passage means (7a) sconnected through first branch intake passages (9a,c,e) with respective ones of said cylinders in said first group, a second common intake passage means (7b) connected through second branch intake passages (9g,i,k) with respective ones of said cylinders in said second group, a third common intake passage means (7c) connected through third branch intake passages (9b,d,f) with respective ones of said cylinders in said third group, a fourth common intake passage means (7d) connected through fourth branch intake passages (9h,j,l) with respective ones of said cylinders in said fourth group, all of said common intake passage means (7a,b,c,d) being located above one of said rows of said cylinders.

Claim 18

A four cycle, 12-cylinder engine including six cylinders (1a,c,e,g,i,k) arranged in a first row and six cylinders (1b,d,f,h,j,l) arranged in a second row, said cylinders of said first row and said cylinders of said second row having a common crankshaft (30) to provide a V-­shaped cylinder arrangement, a first cylinder group comprising three cylinders (1a,c,e) from one end of said first row, a second cylinder group comprising the remaining three cylinders (1g,i,k) in said first row, a third cylinder group comprising three cylinders (1b,d,f) from one end of said second row, a fourth cylinder group comprising the remaining three cylinders (1h,j,l) in said second row, said cylinders in each group having intake stroke timings of 240° spacing in terms of angle of rotation of said crankshaft, a first common intake passage means (7a) sconnected through first branch intake passages (9a,c,e) with respective ones of said cylinders in said first group, a second common intake passage means (7b) connected through second branch intake passages (9g,i,k) with respective ones of said cylinders in said second group, a third common intake passage means (7c) connected through third branch intake passages (9b,d,f) with respective ones of said cylinders in said third group, a fourth common intake passage means (7d) connected through fourth branch intake passages (9h,j,l) with respective ones of said cylinders in said fourth group, all of said common intake passage means (7a,b,c,d) being located above one of said rows of said cylinders.

Claim 19

An engine in accordance with claim 14, wherein: said first and second common intake passage means (7a,7b) are formed integrally and are longitudinally aligned, and separated from each other by a first shut-off valve (20); said second and third common intake passage means (7c,7d) are formed integrally and are longitudinally aligned, and separated from each other by a second shut-off valve (20); said first and second common intake passage means are disposed parallel to said second and third common intake passage means; and said first and second shut-off valve are fixedly connected to a common rotatable horizontal shaft (20a).

Claim 20

A four cycle, 12-cylinder engine in accordance with any of claims 1 to 15, wherein: said common intake passages constitute surge tanks.