Tapered engine exhaust valve
An exhaust valve for an internal combustion engine may comprise a body, including an upper portion, a lower portion, and a tapered portion between an upper end and a lower end of the body, wherein a ratio of (a) a length between an upper end of the upper portion and an upper end of the tapered portion to (b) a length between the upper end of the upper portion and a lower end of the tapered portion is in a range of 0.73 to 0.76, and a taper of the tapered portion is in a range of 0.0012/mm to 0.0030/mm. The exhaust valve may also comprise a head portion extending from a bottom of the lower portion of the body.
1 . An exhaust valve for an internal combustion engine, the exhaust valve comprising:
a body, including an upper portion, a lower portion, and a tapered portion between an upper end and a lower end of the body, wherein a ratio of (a) a length between an upper end of the upper portion and an upper end of the tapered portion to (b) a length between the upper end of the upper portion and a lower end of the tapered portion is in a range of 0.73 to 0.76, and a taper of the tapered portion, measured as a difference between a maximum diameter of the tapered portion and a minimum diameter of the tapered portion, divided by a length of the tapered portion, is in a range of 0.0012/mm to 0.0030/mm; and
a head portion extending from a bottom of the lower portion of the body.
2 . The exhaust valve according to claim 1 , wherein an angle of the tapered portion is in a range of 0.03° to 0.09°.
3 . The exhaust valve according to claim 1 , wherein the body further includes a weld located within the tapered portion.
4 . The exhaust valve according to claim 1 , wherein the body has a guided length along which the exhaust valve is configured to move within a valve guide, and an upper end of the tapered portion is within the guided length and a lower end of the tapered portion coincides with a lower end of the guided length.
5 . The exhaust valve according to claim 4 , wherein a ratio of the guided length to a valve length is in a range of 0.2 to 0.5.
6 . The exhaust valve according to claim 1 , wherein the body is formed of one or more alloys.
7 . The exhaust valve according to claim 6 , wherein each alloy, of the one or more alloys, is selected from the group consisting of: 23-8N, an Inconel® alloy, and SIL1.
8 . An exhaust valve for an internal combustion engine, the exhaust valve comprising:
a body including an upper portion, a lower portion, and a tapered portion between an upper end and a lower end, wherein a ratio of (a) a length between an upper end of the upper portion and an upper end of the tapered portion to (b) a length between the upper end of the upper portion and a lower end of the tapered portion is in a range of 0.77 to 0.79, and a taper of the tapered portion, measured as a difference between a maximum diameter of the tapered portion and a minimum diameter of the tapered portion, divided by a length of the tapered portion, is in a range of 0.0012/mm to 0.0031/mm; and
a head portion extending from bottom of the lower portion of the body,
wherein the exhaust valve is formed of one or more alloys, each alloy being selected from the group consisting of: 23-8N, an Inconel® alloy, and SIL1.
9 . The exhaust valve according to claim 8 , wherein an angle of the tapered portion is in a range of 0.05° to 0.12°.
10 . The exhaust valve according to claim 8 , wherein the body further includes a weld located within the tapered portion.
11 . The exhaust valve according to claim 8 , wherein the body has a guided length along which the body is configured to move within a valve guide, and both an upper end and a lower end of the tapered portion are within the guided length.
12 . The exhaust valve according to claim 11 , wherein a ratio of the guided length to a valve length is in a range of 0.25 to 0.50.
13 . The exhaust valve according to claim 8 , wherein the body and the head portion are formed of different alloys.
14 . A method of manufacturing an exhaust valve for an internal combustion engine, the method comprising:
forging an exhaust valve to have:
a body, including an upper portion, a lower portion, and a tapered portion between an upper end and a lower end, wherein a ratio of (a) a length between an upper end of the upper portion and an upper end of the tapered portion to (b) a length between the upper end of the upper portion and a lower end of the tapered portion is in a range of 0.73 to 0.76, and a taper of the tapered portion, measured as a difference between a maximum diameter of the tapered portion and a minimum diameter of the tapered portion, divided by a length of the tapered portion, is in a range of 0.0012/mm to 0.0031/mm; and
a head portion extending from bottom of the lower portion of the body,
wherein the exhaust valve is formed of one or more alloys.
15 . The method according to claim 14 , wherein an angle of the tapered portion is in a range of 0.03° to 0.09°.
16 . The method according to claim 14 , further comprising attaching at least two parts of the exhaust valve together, at an attachment point located within the tapered portion of the body of the exhaust valve.
17 . The method according to claim 16 , wherein the at least two parts are attached using welding, and the attachment point located within the tapered portion is a weld.
18 . The method according to claim 14 , wherein the body has a guided length along which the body is configured to move within a valve guide, and an upper end of the tapered portion is formed to be within the guided length and a lower end of the tapered portion is formed to coincide with a lower end of the guided length.
19 . The method according to claim 18 , wherein a ratio of the guided length to a valve length is in a range of 0.2 to 0.5.
20 . The method according to claim 14 , wherein each alloy, of the one or more alloys, is selected from the group consisting of: 23-8N, an Inconel® alloy, and SIL1.