Resistance determination for temperature control of heated automotive components

摘要

Electrical resistance of a heater such as a heated fuel injector, is determined for control and monitoring by obtaining a voltage signal 202 proportional to a voltage across the heater (or fuel injector) and obtaining a current signal 214 proportional to an electrical current passing through the heater (or fuel injector). The current signal 214 is modulated to generate a resistance signal 204 proportional to an amount of modulation that makes the current signal 214 approximately equal to the voltage signal 202. The modulation may be pulse-width modulation. The resistance signal 204 may be generated based on a signal that is proportional to the percent duty cycle of the pulse width modulation. A difference of the resistance signal 204 and the voltage signal 202 may be integrated to provide an error signal adapted to cause the modulation to be proportional to an electrical resistance of the heater.