# US 7,073,323 B2 · Secondary air supply apparatus and method for detecting abnormality thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,073,323 B2 - Document ID: US7073323B2 - Status: Granted - Kind: B2 - Application number: 10/234,147 - Filed: 2002-09-05 - Published: 2003-04-03 - Granted: 2006-07-11 - Earliest claimed: 2001-09-14 - Assignees: Toyota Jidosha Kabushiki Kaisha - Inventors: Shigemasa Hirooka; Mamoru Yoshioka - Web page: https://patentgrep.com/patent/US7073323B2 ## CPC - F01N 3/32: using air pump (using jet air pumps F01N3/34; pumps in general F04) - F01N 3/22: Control of additional air supply only, e.g. using by-passes or variable air pump drives - F01N 11/00: Monitoring or diagnostic devices for exhaust-gas treatment apparatus - F01N 2550/14: Systems for adding secondary air into exhaust - Y02T 10/12: Improving ICE efficiencies - Y02T 10/40: Engine management systems - 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) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A secondary air supply apparatus controls emissions from an engine through secondary combustion of combustible matters in exhaust gas accomplished by supplying air to an exhaust pipe upstream of an emission control device. A pressure behavior pattern is determined from a pressure value detected by a pressure sensor disposed between an air pump and an open-close valve, and a pressure variation value. The secondary air supply apparatus determines operational states of the air pump and the open-close valve based on variations of the pressure behavior pattern at the time of a secondary air supply control and at the time of a secondary air stop control. ## Claims ### Claim 1 A secondary air supply apparatus, comprising: a secondary air supply passage for supplying a secondary air to an upstream side of an emission control device in an exhaust system of an internal combustion engine; an opening-closing device that opens and closes the secondary air supply passage; a pressure sensor disposed in the secondary air supply passage; and an abnormality detecting portion that detects an abnormality of a component element based on a mean value of a pressure detected by the pressure sensor, and a pressure variation value. ### Claim 2 A method for detecting an abnormality of a secondary air supply apparatus for supplying a secondary air to an upstream side of an emission control device in an exhaust system of an internal combustion engine, the method comprising: detecting a mean value of a pressure in the secondary air supply passage; calculating a variation value of the pressure value; and detecting an abnormality of a component element based on the mean pressure value and the pressure variation value. ### Claim 3 (depends on 1) The secondary air supply apparatus according to claim 1, wherein the abnormality detecting portion detects a failure mode of the component element from a combination of a pressure behavior pattern occurring at a time of a secondary air supply control and a pressure behavior pattern occurring at a time of a secondary air supply stop control. ### Claim 4 (depends on 3) The secondary air supply apparatus according to claim 3, wherein an air pump is disposed upstream of the opening-closing device, and the pressure sensor is disposed at an intermediate position between the air pump and the opening-closing device. ### Claim 5 (depends on 4) The secondary air supply apparatus according to claim 4, wherein the pressure sensor is an absolute pressure sensor, and the abnormality detecting portion stores, as an atmospheric pressure, a detection value detected by the pressure sensor immediately before a startup of the engine. ### Claim 6 (depends on 4) The secondary air supply apparatus according to claim 4, wherein the abnormality detecting portion further has a function of monitoring an amount of flow through the air pump from an output value from the pressure sensor. ### Claim 7 (depends on 4) The secondary air supply apparatus according to claim 4, wherein the abnormality detecting portion detects clogging of the secondary air supply passage by detecting an ejection pressure of the air pump while driving the air pump at a time of an opening control of the opening-closing device and at a time of a closing control of the opening-closing device. ### Claim 8 (depends on 1) The secondary air supply apparatus according to claim 1, further comprising an air-fuel ratio sensor disposed in the exhaust system, wherein an output of the air-fuel ratio sensor is input to the abnormality detecting portion. ### Claim 9 (depends on 8) The secondary air supply apparatus according to claim 8, wherein the abnormality detecting portion performs an abnormality determination based on a difference between an actual air-fuel ratio and a target air-fuel ratio in accordance with an amount of intake air. ### Claim 10 (depends on 8) The secondary air supply apparatus according to claim 8, wherein the abnormality detecting portion performs an abnormality determination based on a difference between an actual air-fuel ratio and an expected air-fuel ratio in accordance with an engine cooling water temperature. ### Claim 11 (depends on 8) The secondary air supply apparatus according to claim 8, wherein the abnormality detecting portion performs an abnormality determination based on a difference between an air-fuel ratio at a time of a secondary air supply control and an air-fuel ratio at a time of a stop control. ### Claim 12 (depends on 8) The secondary air supply apparatus according to claim 8, wherein the abnormality detecting portion determines whether the air-fuel ratio sensor has activated, by forcibly temporarily turning off the secondary air supply control. ### Claim 13 (depends on 1) The secondary air supply apparatus according to claim 1, wherein the pressure sensor is disposed between the opening-closing device and a check valve. ### Claim 14 (depends on 13) The secondary air supply apparatus to claim 13, wherein the abnormality detecting portion detects an abnormality of the check valve based on the pressure variation value and the pressure value detected by the pressure sensor while the opening-closing device is in a closure control state. ### Claim 15 (depends on 2) The method according to claim 2, further comprising: detecting a failure mode of the component element from a combination of a pressure behavior pattern occurring at a time of a secondary air supply control and a pressure behavior pattern occurring at a time of a secondary air supply stop control. ### Claim 16 (depends on 2) The method according to claim 2, further comprises a step of performing an abnormality determination based on a difference between an actual air-fuel ratio of exhaust gas and an expected air-fuel ratio of exhaust gas in accordance with an engine cooling water temperature. ### Claim 17 (depends on 2) The method according to claim 2, further comprises a step of performing an abnormality determination based on a difference between an air-fuel ratio of exhaust gas at a time of a secondary air supply control and an air-fuel ratio of exhaust gas at a time of a stop control. ### Claim 18 (depends on 2) The method according to claim 2, wherein the secondary air supply apparatus further comprises an air-fuel ratio sensor disposed in the exhaust system, the method further comprises a step of determining whether the air-fuel ratio sensor has activated, by forcibly temporarily turning off the secondary air supply control. ### Claim 19 A method for detecting an abnormality of a secondary air supply apparatus that includes a secondary air supply passage for supplying a secondary air to an upstream side of an emission control device in an exhaust system of an internal combustion engine, an opening-closing device that opens and closes the secondary air supply passage, a pressure sensor disposed in the secondary air supply passage, the method comprising: detecting a mean value of a pressure in the secondary air supply passage; calculating a variation value of the pressure value; detecting an abnormality of a component element based on the mean pressure value and the pressure variation value. ### Claim 20 (depends on 2) The method according to claim 2, wherein the pressure sensor is disposed between the opening-closing device and a check valve, the method includes a step of detecting an abnormality of the check valve based on the pressure variation value and the pressure value detected by the pressure sensor while the opening-closing device is in a closure control state. ### Claim 21 (depends on 2) The method according to claim 2, further comprises a step of performing an abnormality determination based on a difference between an actual air-fuel ratio of exhaust gas and a target air-fuel ratio of exhaust gas in accordance with an amount of intake air. ### Claim 22 (depends on 15) The method according to claim 15, wherein an air pump is disposed upstream of the opening-closing device, and the pressure sensor is disposed at an intermediate position between the air pump and the opening-closing device, the method includes a step of monitoring an amount of flow through the air pump from an output value from the pressure sensor. ### Claim 23 (depends on 15) The method according to claim 15, wherein an air pump is disposed upstream of the opening-closing device, and the pressure sensor is disposed at an intermediate position between the air pump and the opening-closing device, the method further comprises a step of detecting clogging of the secondary air supply passage by detecting an ejection pressure of the air pump while driving the air pump at a time of an opening control of the opening-closing device and at a time of a closing control of the opening-closing device. ### Claim 24 (depends on 1) The secondary air supply apparatus according to claim 1, further comprising a check valve disposed downstream of the opening-closing device. ### Claim 25 (depends on 24) The method according to claim 24, further comprising a check valve disposed downstream of the opening-closing device.