# US 11,994,051 B1 · Vehicle bypass catalyst diagnostic system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,994,051 B1 - Document ID: US11994051B1 - Status: Granted - Kind: B1 - Application number: 18/342,371 - Filed: 2023-06-27 - Granted: 2024-05-28 - Earliest claimed: 2023-06-27 - Assignees: Fca US LLC - Applicants: Fca US LLC - Inventors: Steven C Wante; Roger C Sager; Jeff Brand - Web page: https://patentgrep.com/patent/US11994051B1 ## CPC - F01N 11/002: {the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus} - F01N 3/105: {General auxiliary catalysts, e.g. upstream or downstream of the main catalyst} - F01N 3/2053: {By-passing catalytic reactors, e.g. to prevent overheating} - F01N 11/00: Monitoring or diagnostic devices for exhaust-gas treatment apparatus - F01N 13/008: {Mounting or arrangement of exhaust sensors in or on exhaust apparatus (sensor arrangements for engine control F02D41/1439)} - G07C 5/0808: {Diagnosing performance data (testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005)} - F01N 2550/02: Catalytic activity of catalytic converters - F01N 2560/06: the means being a temperature sensor - F01N 2560/14: having more than one sensor of one kind - F01N 2900/1404: Exhaust gas temperature - F01N 2900/1602: Temperature of exhaust gas apparatus - 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) - G07C: TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE ## Abstract An engine system includes an internal combustion engine, a main exhaust aftertreatment system with a main catalytic converter, and a light-off catalyst bypass system with a bypass passage and a bypass catalytic converter. An emissions control system includes a controller in signal communication with a first temperature sensor disposed upstream of the bypass catalytic converter, and a second temperature sensor disposed downstream of the bypass catalytic converter. The emissions control system performs a diagnostic of the bypass catalytic converter, including (i) monitoring signals from the first and second temperature sensors for a predetermined time period during an engine cold start condition, (ii) determining a temperature of an inlet of the bypass catalytic converter, (iii) determining a temperature of an outlet of the bypass catalytic converter, and (iv) comparing the bypass catalytic converter outlet temperature to the bypass catalytic converter inlet temperature to determine if the bypass catalytic converter has failed. ## Claims ### Claim 1 An internal combustion engine system comprising: an internal combustion engine; a main exhaust aftertreatment system with a main catalytic converter configured to receive exhaust gas from the internal combustion engine; a light-off catalyst bypass system with a bypass passage and a bypass catalytic converter configured to selectively receive exhaust gas from the internal combustion engine; and an emissions control system including a controller in signal communication with a first temperature sensor disposed upstream of the bypass catalytic converter, and a second temperature sensor disposed downstream of the bypass catalytic converter, wherein the emissions control system is configured to perform a diagnostic of the bypass catalytic converter to determine if the bypass catalytic converter meets a predetermined conversion efficiency, comprising: monitoring, by the controller, signals from the first and second temperature sensors for a predetermined time period during an engine cold start condition; determining, by the controller, a temperature of an inlet of the bypass catalytic converter, based on the signals from the first temperature sensor; determining, by the controller, a temperature of an outlet of the bypass catalytic converter, based on the signals from the second temperature sensor; and comparing, by the controller, the bypass catalytic converter outlet temperature to the bypass catalytic converter inlet temperature over the predetermined time period to determine if the bypass catalytic converter has failed, wherein if the bypass catalytic converter outlet temperature exceeds the inlet temperature during or at the end of the predetermined time period, the controller sets the bypass catalytic converter as passing, thereby indicating a healthy bypass catalyst conversion efficiency; and wherein if the bypass catalytic converter outlet temperature is less than or equal to the inlet temperature during or at the end of the predetermined time period, the controller sets the bypass catalytic converter as failing, thereby indicating an inefficient catalyst conversion efficiency. ### Claim 2 (depends on 1) The internal combustion engine system of claim 1, wherein the bypass catalytic converter diagnostic is performed only during the engine cold start condition before the main catalytic converter has reached a light-off temperature. ### Claim 3 (depends on 1) The internal combustion engine system of claim 1, wherein if the bypass catalytic converter outlet temperature exceeds a predetermined threshold during or at the end of the predetermined time period, the controller sets the bypass catalytic converter as passing, and wherein if the bypass catalytic converter outlet temperature is less than the predetermined threshold during or at the end of the predetermined time period, the controller sets the bypass catalytic converter as failing. ### Claim 4 (depends on 3) The internal combustion engine system of claim 3, wherein the predetermined threshold is 500° F. ### Claim 5 (depends on 3) The internal combustion engine system of claim 3, wherein the diagnostic further includes determining, by the controller, a rate of change of the temperature of the bypass catalytic converter outlet, based on the signals from the second temperature sensor. ### Claim 6 (depends on 5) The internal combustion engine system of claim 5, wherein if the rate of change exceeds a predetermined rate of change threshold, the controller sets the bypass catalytic converter as passing, and wherein if the rate of change is less than the predetermined rate of change threshold, the controller sets the bypass catalytic converter as failing. ### Claim 7 (depends on 1) The internal combustion engine system of claim 1, further comprising: an exhaust manifold configured to supply exhaust gas through a main outlet duct to the main exhaust aftertreatment system and the main catalytic converter, wherein the bypass passage is in fluid communication with the exhaust manifold. ### Claim 8 (depends on 7) The internal combustion engine system of claim 7, further comprising a bypass valve configured to move between a first position that enables exhaust gas to flow through the bypass passage, and a second position that prevents exhaust gas flow through the bypass passage and bypass catalytic converter. ### Claim 9 (depends on 8) The internal combustion engine system of claim 8, further comprising a turbocharger having a turbine, wherein the bypass passage is configured to bypass the turbine. ### Claim 10 (depends on 9) The internal combustion engine system of claim 9, wherein when the bypass valve is in the first position, the turbine is operated in a reverse rotation to facilitate preventing the exhaust gas from passing through the turbine. ### Claim 11 A diagnostic method for a bypass catalytic converter of an internal combustion engine system to determine if the bypass catalytic converter meets a predetermined conversion efficiency, the method comprising: an internal combustion engine; a main exhaust aftertreatment system with a main catalytic converter configured to receive exhaust gas from the internal combustion engine; a light-off catalyst bypass system with a bypass passage and the bypass catalytic converter configured to selectively receive exhaust gas from the internal combustion engine; and an emissions control system including a controller in signal communication with a first temperature sensor disposed upstream of the bypass catalytic converter, and a second temperature sensor disposed downstream of the bypass catalytic converter, the diagnostic method comprising: monitoring, by the controller, signals from the first and second temperature sensors for a predetermined time period during an engine cold start condition; determining, by the controller, a temperature of an inlet of the bypass catalytic converter, based on the signals from the first temperature sensor; determining, by the controller, a temperature of an outlet of the bypass catalytic converter, based on the signals from the second temperature sensor; and comparing, by the controller, the bypass catalytic converter outlet temperature to the bypass catalytic converter inlet temperature over the predetermined time period to determine if the bypass catalytic converter has failed, wherein if the bypass catalytic converter outlet temperature exceeds the inlet temperature during or at the end of the predetermined time period, the controller sets the bypass catalytic converter as passing, thereby indicating a healthy bypass catalyst conversion efficiency; and wherein if the bypass catalytic converter outlet temperature is less than or equal to the inlet temperature during or at the end of the predetermined time period, the controller sets the bypass catalytic converter as failing, thereby indicating an inefficient catalyst conversion efficiency. ### Claim 12 (depends on 11) The diagnostic method of claim 11, wherein the bypass catalytic converter diagnostic is performed only during the engine cold start condition before the main catalytic converter has reached a light-off temperature. ### Claim 13 (depends on 11) The diagnostic method of claim 11, further comprising wherein if the bypass catalytic converter outlet temperature exceeds a predetermined threshold during or at the end of the predetermined time period, the controller sets the bypass catalytic converter as passing, and wherein if the bypass catalytic converter outlet temperature is less than the predetermined threshold during or at the end of the predetermined time period, the controller sets the bypass catalytic converter as failing. ### Claim 14 (depends on 13) The diagnostic method of claim 13, further comprising: determining, by the controller, a rate of change of the temperature of the bypass catalytic converter outlet, based on the signals from the second temperature sensor, wherein if the rate of change exceeds a predetermined rate of change threshold, the controller sets the bypass catalytic converter as passing, and wherein if the rate of change is less than the predetermined rate of change threshold, the controller sets the bypass catalytic converter as failing. ### Claim 15 (depends on 11) The diagnostic method of claim 11, wherein the light-off catalyst bypass system further includes a bypass valve in signal communication with the controller and configured to move between a first position that enables exhaust gas to flow through the bypass passage, and a second position that prevents exhaust gas flow through the bypass passage and bypass catalytic converter. ### Claim 16 (depends on 15) The diagnostic method of claim 15, further comprising: determining, by the controller, if the internal combustion engine is under the cold start condition; and moving, by the controller, the bypass valve to the first position if the engine is under the cold start condition. ### Claim 17 (depends on 16) The diagnostic method of claim 16, further comprising: determining, by the controller, if a low-flow condition exists in the engine exhaust before monitoring the signals from the first and second temperature sensors, and wherein the predetermined time period is between five seconds and fifteen seconds. ### Claim 18 (depends on 11) The diagnostic method of claim 11, further comprising illuminating a malfunction indicator light (MIL) if the bypass catalytic converter is determined to have failed.