# US 11,112,333 B2 · Sensor failure diagnostic apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,112,333 B2 - Document ID: US11112333B2 - Status: Granted - Kind: B2 - Application number: 15/763,602 - Filed: 2016-09-21 - Published: 2018-09-27 - Granted: 2021-09-07 - Earliest claimed: 2015-11-23 - Assignees: Denso Corporation - Applicants: Denso Corporation - Inventors: Atsunori Okabayashi; Shinya Hoshi - Web page: https://patentgrep.com/patent/US11112333B2 ## CPC - G01M 15/02: Details or accessories of testing apparatus - F02B 77/04: Cleaning of, preventing corrosion or erosion in, or preventing unwanted deposits in, combustion engines - F02B 77/085: {with sensors measuring combustion processes, e.g. knocking, pressure, ionization, combustion flame} - F02D 19/0623: {Failure diagnosis or prevention; Safety measures; Testing} - F02D 19/0634: {Determining a density, viscosity, composition or concentration (F02D19/087 takes precedence)} - F02D 35/023: {by determining the cylinder pressure} - F02D 35/028: {by determining the combustion timing or phasing} - F02D 41/222: {relating to the failure of sensors or parameter detection devices} - G01M 15/042: {by monitoring a single specific parameter not covered by groups G01M15/06 - G01M15/12} - G01M 15/048: {by monitoring temperature} - G01M 15/08: by monitoring pressure in cylinders - G01M 15/11: by detecting misfire - F02D 2200/0611: Fuel type, fuel composition or fuel quality - F02M 26/25: with coolers having bypasses - Y02T 10/30: Use of alternative fuels, e.g. biofuels - Y02T 10/40: Engine management systems - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - 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) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A sensor failure diagnostic apparatus includes a first estimation unit to estimate a mixing ratio of each type of a molecular structure included in a fuel, based on combustion parameters when a combustion of an internal combustion engine is executed in different combustion conditions, among the combustion parameters sensed by a combustion sensor, a second estimation unit to estimate the mixing ratio, based on characteristic parameters sensed by a characteristic sensor, a combustion sensor diagnostic unit to determine whether a failure of the combustion sensor exists, based on a sensed value of the combustion sensor when the combustion is not executed, and a characteristic sensor diagnostic unit to determine whether a failure of the characteristic sensor exists, by comparing the mixing ratio estimated by the first estimation unit with the mixing ratio estimated by the second estimation unit when the combustion sensor diagnostic unit determines the combustion sensor is normal. ## Claims ### Claim 1 A sensor failure diagnostic apparatus for a combustion system including a combustion sensor configured to sense a combustion parameter indicating a combustion state of an internal combustion engine and a characteristic sensor configured to sense a characteristic parameter indicating a characteristic of a fuel used in a combustion of the internal combustion engine, the sensor failure diagnostic apparatus comprising: a first estimation unit configured to estimate a first mixing ratio of each of types of a molecular structure included in the fuel using the combustion parameters sensed by the combustion sensor when the combustion is executed in different combustion conditions; a second estimation unit configured to estimate a second mixing ratio using the characteristic parameters sensed by the characteristic sensor; a combustion sensor diagnostic unit configured to determine whether a failure of the combustion sensor exists by using values other than the first mixing ratio and the second mixing ratio; and a characteristic sensor diagnostic unit configured to, upon the combustion sensor diagnostic unit determining that the failure of the combustion sensor does not exist, determine whether a failure of the characteristic sensor exists by comparing a difference between the first mixing ratio and the second mixing ratio with a threshold value, wherein the values indicate a pressure in the internal combustion engine and are sensed by the combustion sensor when the combustion is not executed in the internal combustion engine. ### Claim 2 (depends on 1) The sensor failure diagnostic apparatus according to claim 1, wherein the types of the molecular structure include at least one of a normal paraffin type, a side chain paraffin type, a naphthenic type or an aromatic type. ### Claim 3 (depends on 1) The sensor failure diagnostic apparatus according to claim 1, wherein the characteristic parameter includes at least one of a kinematic viscosity of the fuel, a density of the fuel, a ratio of hydrogen to carbon included in the fuel or a low-level heat dissipation amount of the fuel. ### Claim 4 (depends on 1) The sensor failure diagnostic apparatus according to claim 1, wherein the combustion condition is a condition specified by a combination of plural types of combustion condition values, and the combustion condition values include at least one of a cylinder pressure, a cylinder temperature, an intake-gas oxygen concentration or a fuel injection pressure, in a combustion chamber of the internal combustion engine. ### Claim 5 (depends on 1) The sensor failure diagnostic apparatus according to claim 1, wherein the internal combustion engine is a compression self-ignition type, and the combustion parameter is a time period from a time point that the fuel is injected into a combustion chamber of the internal combustion engine to a time point that the fuel is self-ignited, or is a time period from a time point that the fuel injection is instructed to the time point that the fuel is self-ignited. ### Claim 6 (depends on 1) The sensor failure diagnostic apparatus according to claim 1, wherein a microcomputer acquires the values sensed by the combustion sensor and acquires a sensed waveform obtained from the sensed values. ### Claim 7 A sensor failure diagnostic apparatus for a combustion system, comprising: a combustion sensor configured to sense a combustion parameter indicating a combustion state of an internal combustion engine; a characteristic sensor configured to sense a first characteristic parameter indicating a characteristic of a fuel used in a combustion of the internal combustion engine; and processing circuitry including at least one processor, the processing circuitry configured to: estimate a second characteristic parameter using the combustion parameters sensed by the combustion sensor when the combustion is executed in different combustion conditions, the first characteristic parameter and the second characteristic parameter each having a correlation with a mixing ratio of each of types of a molecular structure included in the fuel; and upon the combustion sensor being determined to be operating normally, determine whether the failure of the characteristic sensor exists, by comparing a difference between the first characteristic parameter and the second characteristic parameter with a threshold value. ### Claim 8 (depends on 7) The sensor failure diagnostic apparatus according to claim 7, wherein the characteristic parameter includes at least one of a kinematic viscosity of the fuel, a density of the fuel, a ratio of hydrogen to carbon included in the fuel or a low-level heat dissipation amount of the fuel. ### Claim 9 (depends on 7) The sensor failure diagnostic apparatus according to claim 7, wherein the combustion condition is a condition specified by a combination of plural types of combustion condition values, and the combustion condition values include at least one of a cylinder pressure, a cylinder temperature, an intake-gas oxygen concentration or a fuel injection pressure, in a combustion chamber of the internal combustion engine. ### Claim 10 (depends on 7) The sensor failure diagnostic apparatus according to claim 7, wherein the internal combustion engine is a compression self-ignition type, and the combustion parameter is a time period from a time point that the fuel is injected into a combustion chamber of the internal combustion engine to a time point that the fuel is self-ignited, or is a time period from a time point that the fuel injection is instructed to the time point that the fuel is self-ignited. ### Claim 11 A sensor failure diagnostic apparatus, comprising: a combustion sensor configured to sense a combustion parameter indicating a combustion state of an internal combustion engine; a characteristic sensor configured to sense a characteristic parameter indicating a characteristic of a fuel used in a combustion of the internal combustion engine; and processing circuitry including at least one processor, the processing circuitry configured to: estimate a first mixing ratio of each of types of a molecular structure included in the fuel using the combustion parameters sensed by the combustion sensor when the combustion is executed in different combustion conditions; estimate a second mixing ratio using the characteristic parameters sensed by the characteristic sensor; determine whether a failure of the combustion sensor exists by using values other than the first mixing ratio and the second mixing ratio; and upon determining that the failure of the combustion sensor does not exist, determine whether a failure of the characteristic sensor exists by comparing a difference between the first mixing ratio and the second mixing ratio with a threshold value, wherein the values indicate a pressure in the internal combustion engine and are sensed by the combustion sensor when the combustion is not executed in the internal combustion engine. ### Claim 12 (depends on 11) The sensor failure diagnostic apparatus according to claim 11, wherein a microcomputer acquires the values sensed by the combustion sensor and acquires a sensed waveform obtained from the sensed values.