Under certain conditions, such as light rain, heavy fog, or back spray from other vehicles on wet roads, the windshield wipers may cause smearing of the windshield. This is due to a wet/dry condition of the windshield where insufficient moisture is available for continuous wiping. To overcome this, it is desirable to provide intermittent operation where the wiper blade dwells for an interval time before starting the next cycle. This dwell period may be accomplished by electrical or mechanical means. This paper discusses the various approaches with special emphasis on the electronic wiper timing devices.
