# US 8,788,223 B2 · Comprehensive method of electrical fluid heating system fault detection and handling > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,788,223 B2 - Document ID: US8788223B2 - Status: Granted - Kind: B2 - Application number: 13/247,175 - Filed: 2011-09-28 - Published: 2012-05-03 - Granted: 2014-07-22 - Earliest claimed: 2010-10-29 - Assignees: GM Global Technology Operations LLC - Applicants: Mark R. Willey; Charles J. Bongiorno; David A. Bodenmiller; Craig Atiyeh; Aaron C. Osmun - Inventors: Mark R. Willey; Charles J. Bongiorno; David A. Bodenmiller; Craig Atiyeh; Aaron C. Osmun - Web page: https://patentgrep.com/patent/US8788223B2 ## CPC - G01R 31/50: Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections (testing of sparking plugs H01T13/58) - G01R 31/088: {Aspects of digital computing} - G01R 31/1272: {of cable, line or wire insulation, e.g. using partial discharge measurements (locating faults in cables G01R31/083)} - G01R 31/343: {in operation} - H02H 1/0015: {Using arc detectors} - H05B 1/0236: {for vehicles} - B60H 2001/2231: {for proper or safe operation of the heater} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - B60H: ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES ## Abstract A method and system are provided to eliminate the risk of over temperature concerns associated with electrical heating devices, which if undetected may result in an electrical over temperature condition. The electrical heating system may be applied to the detection and control structure of other automotive electrical loads where thermal concerns may exist. The electrical heating system combines several layers of fault detection strategies, to form a unique comprehensive approach to prevent and detect potential electrical fault conditions, which if undetected and/or controlled may result in an electrical over temperature condition. ## Claims ### Claim 1 A heating system for a vehicle, the system comprising: a heating control module comprising a microprocessor configured for heating fault detection and heating fault handling, a first field effect transistor (FET) operatively connected to the microprocessor, and a second field effect transistor (FET) operatively connected to the microprocessor; and a heating module comprising a heating element, a first thermistor operatively connected to the microprocessor, and a second thermistor operatively connected to the microprocessor; wherein the microprocessor is configured to: determine a fault condition when a temperature difference between a first temperature of the first thermistor and a second temperature of the second thermistor exceeds a temperature difference threshold; determine the fault condition when at least one of the first temperature of the first thermistor and the second temperature of the second thermistor is less than a minimum temperature after the first FET is powered on and the second FET is powered on; determine the fault condition when the first FET is powered on and the second FET is powered off and when the microprocessor does not detect logic voltage at an analog input; and determine the fault condition when the first FET is powered off and the second FET is powered off and when the microprocessor does not detect half the logic voltage at the analog input. ### Claim 2 (depends on 1) The heating system of claim 1, wherein the microprocessor is configured to: determine the fault condition when at least one of the first temperature of the first thermistor and the second temperature of the second thermistor exceeds a temperature specification; determine the fault condition when the first FET is powered off and the second FET is powered on and when the microprocessor does not detect 0 volts at the analog input; and determine the fault condition when the first FET is powered on and the second FET is powered on and when the microprocessor does not detect half the logic voltage at the analog input. ### Claim 3 (depends on 1) The heating system of claim 1, wherein the microprocessor is configured to: determine the fault condition when a current from the first FET does not equal a current from the second FET; determine the fault condition when the current from the first FET exceeds a current threshold; and determine the fault condition when the current from the second FET exceeds the current threshold. ### Claim 4 (depends on 1) The heating system of claim 1, wherein a source of the first FET is operatively connected to a battery through a relay; and wherein a drain of the first FET is operatively connected to the heating element. ### Claim 5 (depends on 1) The heating system of claim 1, wherein a source of the second FET is operatively connected to the heating element; and wherein a drain of the second FET is operatively connected to ground. ### Claim 6 (depends on 1) The heating system of claim 1, wherein a gate of the first FET is operatively connected to the microprocessor and a gate of the second FET is operatively connected to the microprocessor. ### Claim 7 (depends on 1) The heating system of claim 1, wherein the microprocessor is configured to detect fault conditions by monitoring at least one of the following: the analog input, the first FET, the second FET, the first thermistor, and the second thermistor. ### Claim 8 (depends on 1) The heating system of claim 1, wherein a top of the heating control module and a top of the heating module are angled at least at a 15 degree angle. ### Claim 9 (depends on 1) The heating system of claim 1, wherein the microprocessor is configured to determine normal operation of the heating system: when the first FET is powered on and the second FET is powered off and when the microprocessor detects logic voltage at the analog input; and when the first FET is powered off and the second FET is powered off and when the microprocessor detects half the logic voltage at the analog input. ### Claim 10 (depends on 1) The heating system of claim 1, wherein the microprocessor is configured to determine normal operation of the heating system: when the first FET is powered off and the second FET is powered on and when the microprocessor detects ground at the analog input; when the first FET is powered on and the second FET is powered on and when the microprocessor detects half logic power voltage at the analog input; and when the first FET is powered on and the second FET is powered on and when the microprocessor detects that a current from the first FET equals a current from the second FET. ### Claim 11 A method for a heating system of a vehicle, the method comprising: configuring a heating control module comprising a microprocessor configured for heating fault detection and heating fault handling, a first field effect transistor (FET) operatively connected to the microprocessor, and a second field effect transistor (FET) operatively connected to the microprocessor; and configuring a heating module comprising a heating element, a first thermistor operatively connected to the microprocessor, and a second thermistor operatively connected to the microprocessor; wherein the microprocessor is configured to: determine a fault condition when a temperature difference between a first temperature of the first thermistor and a second temperature of the second thermistor exceeds a temperature difference threshold; determine the fault condition when at least one of the first temperature of the first thermistor and the second temperature of the second thermistor is less than a minimum temperature after the first FET is powered on and the second FET is powered on; determine the fault condition when the first FET is powered on and the second FET is powered off and when the microprocessor does not detect logic voltage at an analog input; and determine the fault condition when the first FET is powered off and the second FET is powered off and when the microprocessor does not detect half the logic voltage at the analog input. ### Claim 12 (depends on 11) The method of claim 11, wherein the microprocessor is configured to: determine the fault condition when at least one of the first temperature of the first thermistor and the second temperature of the second thermistor exceeds a temperature specification; determine the fault condition when the first FET is powered off and the second FET is powered on and when the microprocessor does not detect 0 volts at the analog input; and determine the fault condition when the first FET is powered on and the second FET is powered on and when the microprocessor does not detect half the logic voltage at the analog input. ### Claim 13 (depends on 11) The method of claim 11, wherein the microprocessor is configured to: determine the fault condition when a current from the first FET does not equal a current from the second FET; determine the fault condition when the current from the first FET exceeds a current threshold; and determine the fault condition when the current from the second FET exceeds the current threshold. ### Claim 14 (depends on 11) The method of claim 11, wherein a source of the first FET is operatively connected to a battery through a relay; and wherein a drain of the first FET is operatively connected to the heating element. ### Claim 15 (depends on 11) The method of claim 11, wherein a source of the second FET is operatively connected to the heating element; and wherein a drain of the second FET is operatively connected to ground. ### Claim 16 (depends on 11) The method of claim 11, wherein a gate of the first FET is operatively connected to the microprocessor and a gate of the second FET is operatively connected to the microprocessor. ### Claim 17 (depends on 11) The method of claim 11, wherein the microprocessor is configured to detects fault conditions by monitoring at least one of the following: the analog input, the first FET, the second FET, the first thermistor, and the second thermistor. ### Claim 18 (depends on 11) The method of claim 11, wherein a top of the heating control module and a top of the heating module are angled at least at a 15 degree angle. ### Claim 19 (depends on 11) The method of claim 11, wherein the microprocessor is configured to determine normal operation of the heating system: when the first FET is powered on and the second FET is powered off and when the microprocessor detects logic voltage at the analog input; and when the first FET is powered off and the second FET is powered off and when the microprocessor detects half the logic voltage at the analog input. ### Claim 20 (depends on 11) The method of claim 11, wherein the microprocessor is configured to determine normal operation of the heating system: when the first FET is powered off and the second FET is powered on and when the microprocessor detects ground at the analog input; when the first FET is powered on and the second FET is powered on and when the microprocessor detects half logic power voltage at the analog input; and when the first FET is powered on and the second FET is powered on and when the microprocessor detects that a current from the first FET equals a current from the second FET.