Windshield wiper de-icing

Abstract

Methods and apparatus are provided for vehicle windshield washing-wiping and wiper de-icing. Primary nozzles provide washing fluid to the windshield during normal operations and secondary nozzles bathe the wiper arms with washing fluid to de-ice the wipers during a de-icing mode. Washing fluid is drawn from a reservoir and delivered to the nozzles by a pump. When the outside air temperature T is greater than Tc, the critical temperature for ice formation, the wipers and washing-wiping proceed normally with washing fluid delivered to the primary nozzles for windshield washing. When T≦Tc and the wipers are not moving, a washer fluid supply line valve delivers washing fluid to the secondary nozzles to de-ice the wipers. The wiper motor, washing fluid pump and valve are operated by a controller based on inputs from wiper position and air temperature sensors, using predetermined information stored in on-board memory.

Description

TECHNICAL FIELD [0001] The present invention generally relates to vehicle windshield wiper systems, and more particularly, to windshield wiper and washer systems providing wiper blade de-icing. BACKGROUND [0002] It is well known in the art to provide vehicles with windshield wipers and windshield washers. In modern vehicles, the windshield washer nozzles are often mounted on the wiper blades so that they spray more of the washer fluid on the windshield where it is desired and inject less into the vehicle slipstream. Examples of various windshield wiping-washing arrangements are described in Patents GB 430366 to Rawlinson, U.S. Pat. No. 2,961,168 to Webb, U.S. Pat. No. 3,213,493 to Chichester, U.S. Pat. No. 3,230,564 to McDevitt, U.S. Pat. No. 6,234,410 B1 to Martin et al, and U.S. Pat. No. 6,082,636 to Yoshida et al. A wiper de-icing system is described in U.S. Pat. No. 6,438,789 B1. [0003]FIG. 1 is a simplified representation of prior art vehicle windshield wiping-washing system 20...

AI Technical Summary

Benefits of technology

[0007] An apparatus is provided for vehicle windshield washing-wiping and wiper de-icing. Primary wash-spray nozzles provide washing fluid to the windshield during normal washing operations. Secondary de-icing nozzles spray washing fluid on the wipers when the wipers are at rest. The best occurs when the outside air temperature drops below a critical temperature Tc for ice formation. Washing fluid is supplied to the nozzles by a pump coupled between a washing fluid reservoir and the nozzles. One or more valves in the washing fluid supply line(s) direct the washing fluid flow to the nozzles. There is desirably a sensor for determining outside air temperature, a wiper position sensor for determining when the wipers are at rest, a wiper actuation motor for running the wipers and a controller coupled to the pump, valve(s), sensors and wiper motor for managing the operation thereof.

[0008] A method is provided for operating a vehicle windshield washing-wiping and wiper de-icing system. In response to a user activating a ‘wash’ switch or equivalent, the washing fluid pump is turned on to start the washing (and de-icing) cycle. It continues to run as long as the user activates that switch. When the outside air temperature T is greater than Tc, the critical temperature for ice formation, the wipers and washing-wiping proceed normally. The running pump delivers washing fluid from the reservoir to the primary wash-nozzles for windshield washing and no fluid is delivered to the secondary de-icing nozzles. When T≦Tc and the wipers are not moving, a valve in the washer fluid supply line operates and the running pump delivers washing fluid to the secondary nozzles to de-ice the wipers and / or reduce ice formation thereon. In the preferred embodiment, the secondary de-icing nozzles do not operate during normal washing operations and the primary wash-nozzles do not operate during de-icing, but this is not essential. When the user releases the ‘wash’ actuator, the pump shuts off, washing and de-icing stop and the wipers switch to a ‘drying’ mode for a time t1. Thereafter, the system preferably resets to whatever state or mode it was in prior to initiation of the wash cycle.

Problems solved by technology

However, present day wiper-washer systems still suffer from a number of limitations or disadvantages.

A significant problem with such systems is that they permit ice build-up on the wiper blades during cold weather driving conditions.

When that happens, the wipers blades tend to lose contact with the windshield because the ice can prevent the blade from flexing to follow the contour of the windshield.

When this happens the wiping and / or washing action of the blades becomes progressively less effective.

A smeared windshield and reduced visibility can result.

This is a significant disadvantage.

A limitation of prior art blade de-icing arrangements is that they are more complicated and more expensive that is desired.

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