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.

1 . A vehicle windshield washing and wiper de-icing system for a windshield, the system comprising: 
 a wiper assembly configured to move a windshield wiper across the windshield from a first position through a wiping motion back to the first position;    a first nozzle configured to deliver washing fluid to the windshield before or during the wiping motion; and    a second nozzle configured to deliver washing fluid to the wiper while in the first position, to remove ice therefrom.    
     
     
         2 . The system of  claim 1  further comprising a washing fluid reservoir coupled to the first and second nozzles.  
     
     
         3 . The system of  claim 2  further comprising a washing fluid pump coupled between the reservoir and the first and second nozzles.  
     
     
         4 . The system of  claim 3  further comprising at least one valve between the pump and the second nozzle for regulating washing fluid flow to said second nozzle.  
     
     
         5 . The system of  claim 4  wherein the washing fluid flows to the at least one second nozzle substantially only when not flowing to the first nozzle.  
     
     
         6 . The system of  claim 4  wherein the washing fluid flows to the second nozzle substantially while washing fluid also flows to the first nozzle.  
     
     
         7 . The system of  claim 1  wherein the first position is a pause position where the wiper assembly is temporarily stopped.  
     
     
         8 . The system of  claim 1  wherein the first position is a stowage position where the wiper assembly is situated while off.  
     
     
         9 . The system of  claim 4  comprising at least two valves coupled between the pump and the first and second nozzles, a first valve controlling washing fluid flow to the first nozzle and a second valve controlling washing fluid flow to the second nozzle.  
     
     
         10 . The system of  claim 1  wherein the first nozzle is mounted on the wiper assembly.  
     
     
         11 . The system of  claim 1  wherein the first nozzle is mounted on a body of the vehicle.  
     
     
         12 . The system of  claim 1  wherein the second nozzle is mounted on a body of the vehicle.  
     
     
         13 . A method for windshield washing-wiping and wiper de-icing in a vehicle in response to an operator's ‘wash’ request, wherein the vehicle has a pump for selectively delivering washing fluid to a primary nozzle configured to spray washing fluid on the windshield and a secondary nozzle configured to spray washing fluid on the wiper, the method comprising: 
 starting the pump, and    determining whether or not the outside air temperature T is greater than a predetermined value Tc;    and then if T>Tc,    running the wiper in a wash mode while the pump continues to run,    delivering washing fluid to one or more primary nozzles while the pump continues to run, and    stopping the pump when the operator's ‘wash’ request ends;    else if T≦Tc, then    running the wipers in a de-icing mode while the pump continues to run, and determining whether the wipers are moving, and    if not moving, delivering washing fluid to the secondary nozzle while the pump continues to run; or    if moving, not delivering washing fluid to the secondary nozzle; and stopping the pump when the ‘wash’ request from the operator ends.    
     
     
         14 . The method of  claim 13  further comprising, following either stopping step: 
 running the wipers in a further mode to promote drying of the windshield.    
     
     
         15 . The method of  claim 14  further comprising following the last running step: 
 returning operation of the wipers to whatever operating mode existed prior to the operator's ‘wash’ request.    
     
     
         16 . The method of  claim 13  further comprising, following either stopping step: 
 running the wipers in a further mode for time duration t 1  to promote drying of the windshield.    
     
     
         17 . A vehicle mounted system for wiping and washing windshields and de-icing windshield wipers, comprising: 
 at least one windshield wiper;    an actuator coupled to the at least one wiper for moving the wiper from a rest position across the windshield and back to the rest position;    a wash-mode switch;    an outside air temperature sensor;    a reservoir adapted to receive washing fluid;    a washing fluid pump coupled to the reservoir;    a valve coupled to the pump;    a first plurality of nozzles coupled to the pump for spraying washing fluid on the windshield while the pump is pumping;    a second plurality of second nozzles coupled to the at least one valve for spraying washing fluid on the wipers while the pump is pumping and the valve is open; and    a controller coupled to the switch, the actuator, the sensor, the pump and the valve, wherein in response to a signal received from the switch, the controller turns on the pump and compares the outside air temperature T received from the sensor with a predetermined stored value Tc, and then if T <Tc, turns on the actuator and opens the valve to deliver washing fluid to the second plurality of nozzles for de-icing when the wiper is in the rest position.    
     
     
         18 . The system of  claim 17  wherein for T>Tc, the controller turns on the actuator and delivers washing fluid to the first plurality of nozzles to wash the windshield.  
     
     
         19 . The system of  claim 18  wherein after washing or de-icing is complete, the controller returns the system to its state prior to receiving the signal from the wash-mode switch.