Method for controlling heating device of spray water nozzle of e.g. windscreen wiper system, in motor vehicle, involves controlling heat output of heating device based on temperature of motor vehicle, vehicle speed or signal of rain sensor

摘要

The method involves heating a spray water nozzle (2) by a heating device (1), and controlling heat output of the heating device based on external temperature of a motor vehicle, vehicle speed or a signal of a rain sensor (11) by a control unit (6). The heating device made of a positive temperature coefficient (PTC) resistor and operated by a pulse-width modulated (PWM) heating current, where resistance heater is used as the heating device.