# US 10,371,117 B2 · Ignition 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 10,371,117 B2 - Document ID: US10371117B2 - Status: Granted - Kind: B2 - Application number: 15/301,789 - Filed: 2015-04-07 - Published: 2017-04-27 - Granted: 2019-08-06 - Earliest claimed: 2014-04-10 - Assignees: Denso Corporation - Applicants: Denso Corporation - Inventors: Kenta Kyouda; Satoru Nakayama - Web page: https://patentgrep.com/patent/US10371117B2 ## CPC - F02P 15/10: having continuous electric sparks - F02P 3/0442: {using digital techniques (F02P3/0456, F02P3/053, F02P3/0554, F02P3/0558 take precedence)} - F02P 3/0846: {using digital techniques (F02P3/0869, F02P3/0892, F02P3/096 take precedence)} - F02P 3/09: for control of the charging current in the capacitor (F02P15/12 takes precedence) - F02P 5/15: Digital data processing - F02P 9/007: {by supplementary electrical discharge in the pre-ionised electrode interspace of the sparking plug, e.g. plasma jet ignition} - F02P 17/12: Testing characteristics of the spark, ignition voltage or current (testing of sparking plugs H01T13/60) - H01F 38/12: Ignition, e.g. for IC engines - F02D 2200/101: Engine speed - F02P 3/0876: {the storage capacitor being charged by means of an energy converter (DC-DC converter) or of an intermediate storage inductance} - H01F 7/064: {Circuit arrangements for actuating electromagnets (circuit arrangements for obtaining special operating characteristics H01F7/18; driving circuits for electromagnets making use of a switching regulator H01H47/325)} - Y02T 10/40: Engine management systems - F02P: IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES ({anti-pollution means for internal-combustion engines F02B17/00}; specially adapted for rotary-piston or oscillating-piston engines F02B53/12; {ignition of gas turbine plants F02C7/26; ignition of jet propulsion plants F02K9/95; starting of combustion engines F02N9/00}; ignition of combustion apparatus in general, glowing plugs F23Q; measuring of physical variables in general G01; controlling in general G05; data processing in general G06; electrical components in general see Section H; {ignition coils H01F38/12}; sparking plugs H01T13/00) - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - 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) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract An ignition apparatus includes a blow-off determining unit. The blow-off determining unit determines, when a secondary electric current drops below a predetermined threshold value Ia during a determination period, that blow-off has occurred; the determination period is a predetermined time period ΔT from the start of a spark discharge by a main ignition circuit. Further, when it is determined that blow-off has occurred during a main ignition (full-transistor ignition), it is controlled to perform a continuing spark discharge after the main ignition in a next cycle. Moreover, a secondary electric current command value I2a in performing the continuing spark discharge is set to an electric current value that is obtained by adding a predetermined electric current value α to the predetermined threshold value Ia used in the blow-off determination. Consequently, in the next cycle, it is possible to reliably prevent blow-off, thereby reliably preventing a misfire. ## Claims ### Claim 1 An ignition apparatus for an internal combustion engine, the ignition apparatus comprising: a main ignition circuit configured to perform an energization control of a primary coil of an ignition coil, thereby causing a spark discharge in an ignition plug; an energy input circuit configured to selectively input electrical energy to the primary coil during the spark discharge started by operation of the main ignition circuit, thereby applying a secondary electric current in the same direction to a secondary coil of the ignition coil, the energy input circuit also configured to keep the secondary electric current at a secondary electric current command value, thereby continuing the spark discharge started by operation of the main ignition circuit; and an engine control unit (ECU) configured to: determine, when the secondary electric current drops below a predetermined threshold value during a determination period, that blow-off has occurred, the determination period being a predetermined time period ΔT from the start of the spark discharge by the main ignition circuit; and control electrical energy to be inputted by the energy input circuit to the primary coil during the spark discharge started by operation of the main ignition circuit in a next cycle when it is determined, based on a determination result of the engine control unit (ECU), that blow-off has occurred during the spark discharge by the main ignition circuit. ### Claim 2 (depends on 1) The ignition apparatus for an internal combustion engine as set forth in claim 1, wherein the engine control unit (ECU) is further configured to: obtain the secondary electric current command value, which is an electric current value, in the energy input by the energy input circuit in the next cycle by adding a predetermined electric current value to the predetermined threshold value, when it is determined that blow-off has occurred during the spark discharge by the main ignition circuit. ### Claim 3 (depends on 1) The ignition apparatus for an internal combustion engine as set forth in claim 1, wherein the engine control unit (ECU) is further configured to: upon a determination that blow-off has occurred during a continuing spark discharge which is the spark discharge continued by the energy input by the energy input circuit in the cycle after the determination of occurrence of blow-off during the spark discharge by the main ignition circuit, in a next cycle to the cycle, perform the energy input by the energy input circuit with the secondary electric current command value set to an electric current value that is obtained by adding a predetermined electric current value to the predetermined threshold value Ia. ### Claim 4 (depends on 2) The ignition apparatus for an internal combustion engine as set forth in claim 2, wherein the engine control unit (ECU) is further configured to set the predetermined electric current value such that the higher the engine rotational speed, the greater the predetermined electric current value. ### Claim 5 A method of operating an ignition apparatus for an internal combustion engine, the method comprising: performing, using a main ignition circuit, an energization control of a primary coil of an ignition coil, thereby causing a spark discharge in an ignition plug; selectively inputting electrical energy, using an energy input circuit, to the primary coil during the spark discharge started by operation of the main ignition circuit, thereby applying a secondary electric current in the same direction to a secondary coil of the ignition coil, keeping, using the energy input circuit, the secondary electric current at a secondary electric current command value, thereby continuing the spark discharge started by operation of the main ignition circuit; determining, when the secondary electric current drops below a predetermined threshold value during a determination period, that blow-off has occurred, the determination period being a predetermined time period ΔT from the start of the spark discharge by the main ignition circuit; and controlling electrical energy to be inputted by the energy input circuit to the primary coil during the spark discharge started by operation of the main ignition circuit in a next cycle when it is determined, based on a determination result, that blow-off has occurred during the spark discharge by the main ignition circuit. ### Claim 6 (depends on 5) The method of claim 5, further comprising: obtaining the secondary electric current command value, which is an electric current value, in the energy input by the energy input circuit in the next cycle by adding a predetermined electric current value to the predetermined threshold value when it is determined that blow-off has occurred during the spark discharge by the main ignition circuit. ### Claim 7 (depends on 5) The method as set forth in claim 5, further comprising: upon a determination that blow-off has occurred during a continuing spark discharge which is the spark discharge continued by the energy input by the energy input circuit in the cycle after the determination of occurrence of blow-off during the spark discharge by the main ignition circuit, in a next cycle to the cycle, performing the energy input by the energy input circuit with the secondary electric current command value set to an electric current value that is obtained by adding a predetermined electric current value to the predetermined threshold value. ### Claim 8 (depends on 6) The method as set forth in claim 6, further comprising: setting the predetermined electric current value such that the higher the engine rotational speed, the greater the predetermined electric current value.