# US 7,607,345 B2 · Misfire detection apparatus for internal combustion engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,345 B2 - Document ID: US7607345B2 - Status: Granted - Kind: B2 - Application number: 11/912,155 - Filed: 2006-04-19 - Published: 2009-03-05 - Granted: 2009-10-27 - Earliest claimed: 2005-04-20 - Assignees: Toyota Jidosha Kabushiki Kaisha - Inventors: Akihiro Katayama - Web page: https://patentgrep.com/patent/US7607345B2 ## CPC - G01M 15/11: by detecting misfire - F02D 2200/1015: Engines misfires - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) ## Abstract In an internal combustion engine including a flywheel damper, an operation range in which misfire detection is affected by the flywheel damper is set in advance. Whether or not an operation state of the internal combustion engine is within an operation range affected by the flywheel damper is determined. When the operation state is within the operation range affected by the flywheel damper, for example a cylinder specifying process specifying a misfiring cylinder is stopped. By such processing, erroneous detection attributed to irregular rotation fluctuation behavior caused by the flywheel damper can be avoided, and misfire detection performance can be improved. ## Claims ### Claim 1 A misfire detection apparatus for an internal combustion engine that detects a misfire in the internal combustion engine provided with a flywheel damper based on a rotation fluctuation of the engine, wherein an operation range where misfire detection is affected by said flywheel damper is set in advance, the misfire detection apparatus for the internal combustion engine comprises: a determination portion determining whether or not an operation state of said internal combustion engine is within the operation range affected by said flywheel damper; a detection control portion restricting misfire detection, when the operation state of said internal combustion engine is within the operation range affected by said flywheel damper; and a total misfire counter and a cylinder-by-cylinder misfire counter, wherein a count value of said total misfire counter and a count value of said cylinder-by-cylinder misfire counter are both updated, when the operation state of said internal combustion engine is outside the operation range affected by said flywheel damper, and only the count value of said total misfire counter is updated, when the operation state of said internal combustion engine is within the operation range affected by said flywheel damper. ### Claim 2 (depends on 1) The misfire detection apparatus for the internal combustion engine according to claim 1, wherein a cylinder specifying process specifying a misfiring cylinder is not performed, when the operation state of said internal combustion engine is within the operation range affected by said flywheel damper. ### Claim 3 (depends on 1) The misfire detection apparatus for the internal combustion engine according to claim 1, wherein a cylinder number determining process determining a number of misfiring cylinders is not performed, when the operation state of said internal combustion engine is within the operation range affected by said flywheel damper. ### Claim 4 (depends on 2) The misfire detection apparatus for the internal combustion engine according to claim 2, wherein a cylinder number determining process determining a number of misfiring cylinders is not performed, when the operation state of said internal combustion engine is within the operation range affected by said flywheel damper. ### Claim 5 A misfire detection apparatus for an internal combustion engine that detects a misfire in the internal combustion engine provided with a flywheel damper based on a rotation fluctuation of the engine, wherein an operation range where misfire detection is affected by said flywheel damper is set in advance, the misfire detection apparatus for the internal combustion engine comprises: determination means for determining whether or not an operation state of said internal combustion engine is within the operation range affected by said flywheel damper; detection control means for restricting misfire detection, when the operation state of said internal combustion engine is within the operation range affected by said flywheel damper; and a total misfire counter and a cylinder-by-cylinder misfire counter, wherein a count value of said total misfire counter and a count value of said cylinder-by-cylinder misfire counter are both updated, when the operation state of said internal combustion engine is outside the operation range affected by said flywheel damper, and only the count value of said total misfire counter is updated, when the operation state of said internal combustion engine is within the operation range affected by said flywheel damper. ### Claim 6 (depends on 5) The misfire detection apparatus for the internal combustion engine according to claim 5, wherein a cylinder specifying process specifying a misfiring cylinder is not performed, when the operation state of said internal combustion engine is within the operation range affected by said flywheel damper. ### Claim 7 (depends on 5) The misfire detection apparatus for the internal combustion engine according to claim 5, wherein a cylinder number determining process determining a number of misfiring cylinders is not performed, when the operation state of said internal combustion engine is within the operation range affected by said flywheel damper. ### Claim 8 (depends on 6) The misfire detection apparatus for the internal combustion engine according to claim 6, wherein a cylinder number determining process determining a number of misfiring cylinders is not performed, when the operation state of said internal combustion engine is within the operation range affected by said flywheel damper. ### Claim 9 A misfire detection apparatus for an internal combustion engine that detects a misfire in the internal combustion engine provided with a flywheel damper based on a rotation fluctuation of the engine, wherein an operation range where misfire detection is affected by said flywheel damper is set in advance, the misfire detection apparatus for the internal combustion engine comprises an electronic control unit (ECU), a total misfire counter, and a cylinder-by-cylinder misfire counter, wherein said electronic control unit (ECU) determines whether or not an operation state of said internal combustion engine is within the operation range affected by said flywheel damper, said electronic control unit (ECU) updates both a count value of said total misfire counter and a count value of said cylinder-by-cylinder misfire counter, when the operation state of said internal combustion engine is outside the operation range affected by said flywheel damper, and said electronic control unit (ECU) restricts misfire detection and updates only the count value of said total misfire counter, when the operation state of said internal combustion engine is within the operation range affected by said flywheel damper.