# US 2018/0023429 A1 · Timbre Scaled Exhaust System > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0023429 A1 - Document ID: US20180023429A1 - Status: Published application - Kind: A1 - Application number: 15/658,750 - Filed: 2017-07-25 - Published: 2018-01-25 - Earliest claimed: 2016-07-25 - Inventors: David Akiba Borla - Web page: https://patentgrep.com/patent/US20180023429A1 ## CPC - F01N 1/02: by using resonance - F01N 2470/20: Dimensional characteristics of tubes, e.g. length, diameter - F01N 2470/26: Tubes being formed by extrusion, drawing or rolling - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) ## Abstract A timbre scaled internal combustion exhaust system includes: an inlet collector including a single entrance duct at a first end of the collector in fluid communication with an exhaust flow from an internal combustion engine and an exit duct at a second end of the collector; a plurality of non-perforated parallel tuning tubes in fluid communication with the plurality of exit ducts of the inlet collector, the plurality of tuning tubes having lengths and diameters selected based on a desired note of the timbre scaled exhaust system; an outlet collector including a plurality of entrance ducts in fluid communication with the at least first and second tuning tubes and a single exit duct in fluid communication with an outlet of the exhaust system. The inlet collector splits the exhaust flow through the plurality of tuning tubes to create individual notes, and wherein the outlet collector combines the split exhaust flow to create a desired sound of internal combustion engine exhaust. ## Claims ### Claim 1 A timbre-scaled exhaust system comprising: an inlet collector including an entrance duct at a first end of the collector in fluid communication with an exhaust flow from an internal combustion engine and an exit duct at a second end of the collector; a plurality of non-perforated parallel tuning tubes in fluid communication with the plurality of exit ducts of the inlet collector, the plurality of tuning tubes having lengths and diameters selected based on a desired note of the timbre scaled exhaust system; an outlet collector including an entrance duct in fluid communication with the at least first and second tuning tubes and an exit duct in fluid communication with an outlet of the exhaust system; wherein the inlet collector splits the exhaust flow through the plurality of tuning tubes to create individual notes, and wherein the outlet collector combines the split exhaust flow to create a desired sound of internal combustion engine exhaust. ### Claim 2 (depends on 1) The timbre-scaled exhaust system of claim 1, the plurality of tuning tubes further comprising: at least a first tuning tube having a diameter, the diameter selected based on a first desired note and at least a second tuning tube having a second diameter that varies from the diameter of first tuning tube, the diameter of the second tuning tube selected based on a second desired note. ### Claim 3 (depends on 2) The timbre-scaled exhaust system of claim 2, wherein the first tuning tube has a first length and the second tuning tube has a second length that is greater than the length of the first tuning tube. ### Claim 4 (depends on 1) The timbre-scaled exhaust system of claim 1 further comprising a muffler located downstream from the inlet collector, tuning tubes, and outlet collector. ### Claim 5 (depends on 1) The timbre-scaled exhaust system of claim 1, the tuning tubes having a diameter such that sound waves of one of the tuning tubes substantially cancel a noise of soundwaves of another of the tuning tubes. ### Claim 6 (depends on 1) The timbre-scaled exhaust system of claim 1, wherein each of the plurality of tuning tubes is visually exposed. ### Claim 7 (depends on 1) The timbre-scaled exhaust system of claim 1, wherein the inlet collector, tuning tubes, and outlet collector are formed as a single piece by one of extrusion and casting. ### Claim 8 (depends on 1) The timbre-scaled exhaust system of claim 1, wherein the tuning tubes have a diameter of between 1″ and 1.5″. ### Claim 9 (depends on 8) The timbre-scaled exhaust system of claim 8, wherein the tuning tubes have a length of from about 1″ to about 8″. ### Claim 10 (depends on 1) The timbre-scaled exhaust system of claim 1, wherein the tuning tubes comprise between 3 and 5 parallel tuning tubes. ### Claim 11 (depends on 1) The timbre-scaled exhaust system of claim 1, further comprising a plurality of lobes formed around the exit duct of the inlet collector and the entrance duct of the outlet collector, the plurality of lobes shaped to receive the tuning tubes. ### Claim 12 (depends on 1) The timbre-scaled exhaust system of claim 1, wherein the lobes are adapted to receive a first number of tuning tubes in a first configuration and further adapted to receive a second number of tuning tubes in a second configuration. ### Claim 13 A timbre scaled internal combustion exhaust system comprising: an inlet collector including a single entrance duct at a first end of the collector in fluid communication with an exhaust flow from an internal combustion engine and an exit duct at a second end of the collector; a plurality of non-perforated parallel tuning tubes in fluid communication with the plurality of exit ducts of the inlet collector including at least a first tuning tube having a diameter, the diameter selected based on a first desired note and at least a second tuning tube having a second diameter that varies from the diameter of first tuning tube, the diameter of the second tuning tube selected based on a second desired note; an outlet collector including a plurality of entrance ducts in fluid communication with the at least first and second tuning tubes and a single exit duct in fluid communication with an outlet of the exhaust system; wherein the inlet collector splits the exhaust flow through the plurality of tuning tubes to create individual notes, and wherein the outlet collector combines the split exhaust flow to create a desired sound of internal combustion engine exhaust. ### Claim 14 A timbre scaled internal combustion exhaust system comprising: an inlet collector including a single entrance duct at a first end of the collector in fluid communication with an exhaust flow from an internal combustion engine and an exit duct at a second end of the collector; a plurality of non-perforated parallel tuning tubes in fluid communication with the plurality of exit ducts of the inlet collector including at least a first tuning tube having a diameter, the diameter selected based on a first desired note and at least a second tuning tube having a second diameter that varies from the diameter of first tuning tube, the diameter of the second tuning tube selected based on a second desired note; an outlet collector including a plurality of entrance ducts in fluid communication with the at least first and second tuning tubes and a single exit duct in fluid communication with an outlet of the exhaust system; wherein the inlet collector splits the exhaust flow through the plurality of tuning tubes to create individual notes, and wherein the outlet collector combines the split exhaust flow to create a desired sound of internal combustion engine exhaust.