# US 6,941,245 B2 · Method and system for controlling engine temperature by engine derating > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,941,245 B2 - Document ID: US6941245B2 - Status: Granted - Kind: B2 - Application number: 10/654,326 - Filed: 2003-09-03 - Published: 2005-03-03 - Granted: 2005-09-06 - Earliest claimed: 2003-09-03 - Assignees: Detroit Diesel Corporation - Inventors: John Edward Longnecker; Leopold Super; Richard Michael Avery, Jr.; Brian Lewallen - Web page: https://patentgrep.com/patent/US6941245B2 ## CPC - F02D 41/04: Introducing corrections for particular operating conditions (F02D41/14 takes precedence) - F01P 7/167: {by adjusting the pre-set temperature according to engine parameters, e.g. engine load, engine speed} - F01P 11/16: concerning coolant temperature (F01P11/20 takes precedence) - F02D 41/1497: {With detection of the mechanical response of the engine} - F02D 41/22: Safety or indicating devices for abnormal conditions {(in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809)} - F02D 41/042: {for stopping the engine} - F02D 2200/024: Fluid pressure of lubricating oil or working fluid - F02D 2200/0414: Air temperature - F02D 2200/0602: Fuel pressure - F02D 2200/0606: Fuel temperature - F02D 2250/18: Control of the engine output torque - F02D 2250/26: by applying a torque limit - Y02T 10/40: Engine management systems - 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) - F01P: COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES (arrangements in connection with cooling of propulsion units in vehicles B60K11/00; heat-transfer, heat-exchange or heat-storage materials C09K5/00; {cooling of gas-turbine engines F02C7/12}; heat exchange in general, radiators F28) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A method and system for controlling engine temperature by derating torque output of the engine. The method and system operate in cooperation with an electronic control module which is programmable for controlling temperature in the engine by derating maximum engine torque output based on an engine temperature rate of change. This permits the derating to be finely tuned to maximize available torque. ## Claims ### Claim 1 A method to control engine temperature by derating engine torque, the method comprising: calculating a first delta temperature equal to a difference in temperature between a first engine temperature determined during operation of the engine and a predefined operating temperature limit; calculating a first temperature rate of change for the engine, the first temperature rate of change corresponding with a change in engine temperature over a first period of time; determining a first torque limiter for use in derating engine torque, the first torque limiter based on the first delta temperature and the first temperature rate of change; and controlling an engine control module to derate engine torque based on the first torque limiter. ### Claim 2 (depends on 1) The method of claim 1 further comprising the engine control module controlling a maximum torque output of the engine based on the first torque limiter. ### Claim 3 (depends on 2) The method of claim 2 further comprising calculating a second delta temperature equal to a difference in temperature between a second engine temperature determined during operation of the engine and the predefined temperature limit, the second delta temperature less than the first delta temperature and less than a predefined delta temperature limit, calculating a second torque limiter and derating engine torque based on the second torque limiter, wherein the second torque limiter increases engine torque output relative to the engine derating caused by the first torque estimate. ### Claim 4 (depends on 2) The method of claim 2 further comprising calculating a second delta temperature equal to a difference in temperature between a second engine temperature determined during operation of the engine and the predefined temperature limit, the second delta temperature greater than a predefined delta temperature limit, calculating a second torque limiter and derating engine torque based on the second torque limiter, wherein the second torque limiter at least maintains engine torque output derated by the first torque estimate. ### Claim 5 (depends on 4) The method of claim 4 wherein calculating the second torque limiter comprises calculating a second temperature rate of change for the engine, the second temperature rate of change corresponding with a change in engine temperature over a second period of time, the second torque limiter based on the second delta temperature and the second temperature rate of change. ### Claim 6 (depends on 1) The method of claim 1 wherein determining the first torque limiter comprises selecting the first torque limiter from a look-up table including a percentage value for the first torque limiter as a function of the first delta temperature and the first temperature rate of change. ### Claim 7 (depends on 1) The method of claim 1 wherein determining the engine temperature comprises determining engine coolant temperature. ### Claim 8 (depends on 1) The method of claim 1 wherein determining the engine temperature comprises determining engine oil temperature. ### Claim 9 (depends on 1) The method of claim 1 wherein determining the engine temperature comprises determining turbocharger compressor outlet air temperature. ### Claim 10 (depends on 1) The method of claim 1 wherein determining the engine temperature comprises determining intake manifold air temperature. ### Claim 11 (depends on 1) The method of claim 1 wherein determining the engine temperature comprises determining the engine temperature for an compression-ignition engine. ### Claim 12 (depends on 1) The method of claim 1 wherein determining the engine temperature comprises determining the engine temperature for a diesel engine. ### Claim 13 An engine control module for use with a compression-ignition internal combustion engine, the module comprising, a means for calculating a first delta temperature equal to a difference in temperature between a first engine temperature determined during operation of the engine and a predefined operating temperature limit; a means for calculating a first temperature rate of change for the engine, the first temperature rate of change corresponding with a change in engine temperature over a first period of time; a means for determining a first torque limiter for use in derating engine torque, the first torque limiter based on the first delta temperature and the first temperature rate of change; and a means for derating engine torque based on the first torque limiter. ### Claim 14 (depends on 13) The method of claim 13 further comprising means for controlling a maximum torque output of the engine based on the first torque limiter. ### Claim 15 A system for use with an internal combustion engine to control engine temperature by derating engine torque, the system comprising: a sensor for determining a first engine temperature during operation of the engine; and an engine control module configured to calculate a first temperature rate of change for the engine, the first temperature rate of change corresponding with a change in engine temperature over a first period of time, the engine control module determining a first torque limiter for use in derating engine torque, the first torque limiter based on the first temperature rate of change. ### Claim 16 (depends on 15) The system of claim 15 wherein the engine control module calculates a first delta temperature equal to a difference in temperature between the first engine temperature and a predefined operating temperature limit, the torque limiter based on the first delta temperature and the first temperature rate of change. ### Claim 17 (depends on 16) The system of claim 16 wherein the engine control module calculates a second delta temperature equal to a difference in temperature between a second engine temperature determined during operation of the engine and the predefined temperature limit, the second delta temperature less than the first delta temperature and less than a predefined delta temperature limit, the engine control module calculating a second torque limiter and derating engine torque based on the second torque limiter, wherein the second torque limiter increases engine torque output relative to the engine derating caused by the first torque estimate. ### Claim 18 (depends on 16) The system of claim 16 wherein the engine control module calculates a second delta temperature equal to a difference in temperature between a second engine temperature determined during operation of the engine and the predefined temperature limit, the second delta temperature greater than a predefined delta temperature limit, the engine control module calculating a second torque limiter and derating engine torque based on the second torque limiter, wherein the second torque limiter at least maintains engine torque output derated by the first torque estimate. ### Claim 19 (depends on 18) The system of claim 18 wherein the engine control module calculates a second temperature rate of change for the engine, the second temperature rate of change corresponding with a change in engine temperature over a second period of time, the second torque limiter based on the second delta temperature and the second temperature rate of change. ### Claim 20 (depends on 16) The system of claim 16 wherein the engine control module selects the first torque limiter from a look-up table including a percentage value for the first torque limiter as a function of the first delta temperature and the first temperature rate of change.