# US 10,502,149 B2 · Method for operating engine in intermittent combustion mode and engine control device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,149 B2 - Document ID: US10502149B2 - Status: Granted - Kind: B2 - Application number: 15/924,948 - Filed: 2018-03-19 - Published: 2018-11-01 - Granted: 2019-12-10 - Earliest claimed: 2017-04-28 - Assignees: Toyota Jidosha Kabushiki Kaisha - Applicants: Toyota Jidosha Kabushiki Kaisha - Inventors: Tomohiro Nakano - Web page: https://patentgrep.com/patent/US10502149B2 ## CPC - F02D 41/0087: {Selective cylinder activation, i.e. partial cylinder operation (deceleration cut-off F02D41/123)} - F02D 41/0002: {Controlling intake air} - F02D 41/3058: {the engine working with a variable number of cycles} - F02D 41/307: {to avoid torque shocks} - F02D 41/345: {Controlling injection timing (F02D41/365 takes precedence)} - F02D 37/02: one of the functions being ignition - F02D 41/123: {the fuel injection being cut-off} - F02D 2200/0404: Throttle position - F02D 2200/1002: Output torque - F02D 2200/602: Pedal position - F02D 2250/21: during a transition between engine operation modes or states - F02D 2250/28: Control for reducing torsional vibrations, e.g. at acceleration - 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 An intermittent combustion mode is executed while cyclically switching an intermittent firing pattern in such a manner that the skipped-cylinder interval is changed by one cylinder at a time. Furthermore, the intermittent firing pattern is switched in such a manner that the fired cylinder ratio in one cycle of switching of the intermittent firing pattern becomes equal to a target fired cylinder ratio. This suppresses the occurrence of vibration and noise having low frequencies that tend to disturb the occupant while limiting an increase in the rotational fluctuation of the engine. ## Claims ### Claim 1 A method for operating an engine in an intermittent combustion mode in such a manner that a fired cylinder ratio of an engine becomes equal to a target fired cylinder ratio set based on an operating state of the engine by repeating an intermittent firing pattern in which n cylinders are successively fired, and then m cylinders are successively skipped, where n and m are variables of natural numbers, the method comprising: switching the intermittent firing pattern in such a manner that one of n and m is set to a value equal to the value before switching the intermittent firing pattern, the other one of n and m is changed by only 1 from the value before switching the intermittent firing pattern, the switching of the intermittent firing pattern is performed cyclically so that, each time the switching of the intermittent firing pattern is performed a predetermined number of times, the intermittent firing pattern that is the same as the previous intermittent firing pattern appears, and the fired cylinder ratio in one cycle of switching of the intermittent firing pattern becomes equal to the target fired cylinder ratio. ### Claim 2 (depends on 1) The method for operating an engine in an intermittent combustion mode according to claim 1, wherein one cycle of switching of the intermittent firing pattern includes no period in which an identical intermittent firing pattern appears consecutively. ### Claim 3 (depends on 1) The method for operating an engine in an intermittent combustion mode according to claim 1, wherein one cycle of switching of the intermittent firing pattern includes a period in which an identical intermittent firing pattern appears consecutively and a period in which an intermittent firing pattern appears consecutively in which one of n and m is changed by only 1 from an immediately preceding intermittent firing pattern. ### Claim 4 (depends on 1) The method for operating an engine in an intermittent combustion mode according to claim 1, wherein in the intermittent firing pattern, n is the number of fired cylinders, and m is the number of skipped cylinders, an intermittent firing pattern in which the number of the fired cylinders is a natural number n1, and the number of the skipped cylinders is a natural number m1 is defined as a first firing pattern, an intermittent firing pattern in which the value of either one of the number of the fired cylinders and the number of the skipped cylinders is equal to the value in the first firing pattern, and in which a difference obtained by subtracting the number of the skipped cylinders from the number of the fired cylinders is greater than the value in the case of the first firing pattern by 1 is defined as a second firing pattern, an intermittent firing pattern in which the value of either one of the number of the fired cylinders and the number of the skipped cylinders is equal to the value in the first firing pattern, and in which a difference obtained by subtracting the number of the skipped cylinders from the number of the fired cylinders is less than the value in the case of the first firing pattern by 1 is defined as a third firing pattern, and a period in which the intermittent combustion mode is executed with the first firing pattern and a period in which the intermittent combustion mode is executed with either one of the second firing pattern and the third firing pattern alternately appear. ### Claim 5 (depends on 4) The method for operating an engine in an intermittent combustion mode according to claim 4, wherein a period in which the intermittent combustion mode is executed with the first firing pattern, a period in which the intermittent combustion mode is executed with the second firing pattern, a period in which the intermittent combustion mode is executed with the first firing pattern, and a period in which the intermittent combustion mode is executed with the third firing pattern appear in this order. ### Claim 6 (depends on 5) The method for operating an engine in an intermittent combustion mode according to claim 5, wherein the switching of the intermittent firing pattern is performed on condition that an engine speed is less than or equal to a preset threshold value, and the intermittent combustion mode is executed by repeating the first firing pattern if the engine speed exceeds the threshold value. ### Claim 7 (depends on 6) The method for operating an engine in an intermittent combustion mode according to claim 6, wherein the threshold value is a value that changes in accordance with the value of the target fired cylinder ratio. ### Claim 8 (depends on 1) The method for operating an engine in an intermittent combustion mode according to claim 1, wherein an intake air amount of one cylinder per one cycle is defined as a cylinder intake air amount, the cylinder intake air amount when a throttle opening degree is maximum is defined as a maximum cylinder intake air amount, a ratio of the cylinder intake air amount to the maximum cylinder intake air amount is defined as an engine load factor, which is represented by KL, a value of the engine load factor at which an output torque of the engine is zero is represented by KL0, and the method comprises adjusting the engine load factor so as to reduce a difference in a value of (KL−KL0)×(n+m)/n+KL0 between before and after the switching of the intermittent firing patterns. ### Claim 9 An engine control device, comprising: a target fired-cylinder-ratio setting section, which sets a target fired cylinder ratio based on an operating state of an engine; and an intermittent combustion command section, which outputs a command signal that commands whether to fire or skip cylinders that are entering a combustion stroke, wherein the intermittent combustion command section outputs the command signal by repeating an output pattern in which the combustion command section commands to successively fire n cylinders and then commands to successively skip firing in m cylinders, where n and m are variables of natural numbers, wherein the intermittent combustion command section switches the intermittent firing pattern in such a manner that one of n and m is set to a value equal to the value before switching the intermittent firing pattern, the other one of n and m is changed by only 1 from the value before switching the intermittent firing pattern, the switching of the output pattern is performed cyclically so that, each time the switching of the output pattern is performed a predetermined number of times, the output pattern that is the same as the previous output pattern appears, and a fired cylinder ratio in one cycle of switching of the output pattern becomes equal to the target fired cylinder ratio. ### Claim 10 (depends on 9) The engine control device according to claim 9, wherein the intermittent combustion command section switches the output pattern in such a manner that one cycle of switching of the output pattern includes no period in which an identical output pattern appears consecutively. ### Claim 11 (depends on 9) The engine control device according to claim 9, wherein the intermittent combustion command section switches the output pattern in such a manner that one cycle of switching of the output pattern includes a period in which an identical output pattern appears consecutively and a period in which an output patterns appears consecutively in which one of n and m is changed by only 1 from an value in the immediately preceding output pattern. ### Claim 12 (depends on 9) The engine control device according to claim 9, wherein in the output pattern, n is the number of the fired cylinders, and m is the number of the skipped cylinders, an output pattern of the command signal in which the number of the fired cylinders is a natural number n1 and the number of the skipped cylinders is a natural number m1 is defined as a first output pattern, an output pattern of the command signal in which the value of either one of the number of the fired cylinders and the number of the skipped cylinders is equal to the value in the first output pattern, and in a difference obtained by subtracting the number of the skipped cylinders from the number of the fired cylinders is greater than the value in the case of the first output pattern by 1 is defined as a second output pattern, an output pattern of the command signal in which the value of either one of the number of the fired cylinders and the number of the skipped cylinders is equal to the value in the first output pattern, and in which a difference obtained by subtracting the number of the skipped cylinders from the number of the fired cylinders is less than the value in the case of the first output pattern by 1 is defined as a third output pattern, and the intermittent combustion command section switches the output pattern in such a manner that a period in which the command signal is output with the first output pattern and a period in which the command signal is output with either one of the second output pattern and the third output pattern alternately appear. ### Claim 13 (depends on 12) The engine control device according to claim 12, wherein the intermittent combustion command section switches the output pattern in such a manner that a period in which the command signal is output in the first output pattern, a period in which the command signal is output in the second output pattern, a period in which the command signal is output in the first output pattern, and a period in which the command signal is output in the third output pattern appear in this order. ### Claim 14 (depends on 13) The engine control device according to claim 13, wherein the intermittent combustion command section switches the output pattern on condition that an engine speed is less than or equal to a preset threshold value, and the intermittent combustion command section outputs the command signal to repeat the first output pattern when the engine speed exceeds the threshold value. ### Claim 15 (depends on 14) The engine control device according to claim 14, wherein the threshold value is set to a value that differs depending on the fired cylinder ratio of the engine. ### Claim 16 (depends on 9) The engine control device according to claim 9, further comprising an air amount adjustment section, wherein an intake air amount of one cylinder per one cycle is defined as a cylinder intake air amount, the cylinder intake air amount when a throttle opening degree is maximum is defined as a maximum cylinder intake air amount, a ratio of the cylinder intake air amount to the maximum cylinder intake air amount is defined as an engine load factor, which is represented by KL, a value of the engine load factor at which an output torque of the engine is zero is represented by KL0, and the air amount adjustment section adjusts the engine load factor so as to reduce a difference in a values of (KL−KL0)×(n+m)/n−KL0 between before and after the switching of the output pattern.