Motor vehicle windscreen or rear-window wiper with modulated washer water jet

摘要

The window wiper system directs a variable jet (51) of water from a nozzle (46) at the windscreen (54) and adjusts it by a pressure controller (48) responsive to a signal (VF) denoting road speed. The pressure is varied by a pulse-width modulator (60) operating advantageously in the frequency range from 0.2 to 2 Hz. The duration of the low level (L) of the pulse is limited so as to guarantee a continuous supply of water. The frequency range enables an existing wiper relay to be clocked by the pulse-width modulator.