Method for checking operability of electrical heating device utilized in motor car for heating urea solution, involves applying testing voltage to electrical heating device, and evaluating electric property of heating device

摘要

The method involves applying testing voltage to an electrical heating device, where the testing voltage is smaller than power supply voltage that is applied for operating the heating device. An electric property i.e. electric resistance, of the heating device is evaluated, where the testing voltage is higher than the half of the power supply voltage. The testing voltage is an operation voltage provided by a 5-volt source for electronic components of a motor car, where the heating device comprises a ceramic positive thermal coefficient heating element.