Washer fluid warming device

Abstract

A warming device capable of quickly increasing a temperature of a washer fluid with a relatively-low current, warming a relatively-large volume of washer fluid, and further retaining a washer fluid in a warmed state for some time after a power supply is turned off is provided. A warming device includes a structure in which a small heating chamber is housed in an inner space of a heat-retaining hot fluid storage chamber and an electric heater is housed in an inner space of the small heating chamber. The heat-retaining hot fluid storage chamber has a heat-insulating structure. The small heating chamber has a moderate thermal conductivity. A washer fluid fed from a washer tank is supplied to the small heating chamber through the heat-retaining hot fluid storage chamber, warmed by the heater and ejected from a washer nozzle.

1 . A washer fluid warming device arranged between a washer tank and a washer nozzle in a washer apparatus on board a vehicle, the washer fluid warming device warming a washer fluid sent in from the washer tank and sending the washer fluid out to the washer nozzle, the device comprising:
 a heat-retaining hot fluid storage chamber including a wall having a heat-insulating structure in which a vacuum layer is provided between an inner wall and an outer wall and including an inner space into which the washer fluid flowing out of the washer tank flows as a result of a washer pump being driven;   a small heating chamber including a wall having a thermal conductivity higher than that of the wall of the heat-retaining hot fluid storage chamber, being housed in the inner space of the heat-retaining hot fluid storage chamber, and further including an inner space into which the washer fluid in the heat-retaining hot fluid storage chamber flows as a result of the washer pump being driven; and   an electric heater housed in the inner space of the small heating chamber, the electric heater warming the washer fluid in the small heating chamber,   wherein the inner space of the heat-retaining hot fluid storage chamber is set to have a size capable of accommodating a volume of washer fluid that is larger than a volume of washer fluid that can be accommodated by the inner space of the small heating chamber; and   wherein the warmed washer fluid flowing out of the small heating chamber is supplied to the washer nozzle as a result of the washer pump being driven.   
     
     
         2 . The washer fluid warming device according to  claim 1 ,
 wherein the heat-retaining hot fluid storage chamber includes an opening that provides communication between an outer space and the inner space thereof;   wherein the small heating chamber with the electric heater housed therein is attached to a lid that occludes the opening; and   wherein the small heating chamber is inserted into the inner space of the heat-retaining hot fluid storage chamber from the opening and thereby housed in the inner space of the heat-retaining hot fluid storage chamber and the opening is occluded by the lid.   
     
     
         3 . The washer fluid warming device according to  claim 2 ,
 wherein the lid includes:   a washer fluid inflow channel that allows the washer fluid to flow from the outside into the heat-retaining hot fluid storage chamber;   a washer fluid outflow channel that allows the washer fluid in the small heating chamber to flow out to the outside; and   an electric wire leading channel that allows an electric wire for supplying power to the electric heater to be led to the outside.   
     
     
         4 . The washer fluid warming device according to  claim 2 ,
 wherein the small heating chamber is formed in a tubular shape extending in a vertical direction;   wherein the washer fluid warming device further includes a plate-shaped movable throttle lid housed in the inner space of the small heating chamber;   wherein the electric heater has a stick-like shape and is arranged along a central axis of the tubular small heating chamber;   wherein the movable throttle lid includes a central hole, and the electric heater is inserted through the central hole and arranged so that the movable throttle lid can ascend/descend along the electric heater, and   wherein upon the movable throttle lid being pushed up by the washer fluid flowing in from a lower portion of the inner space of the small heating chamber, the movable throttle lid makes the washer fluid on an upper side of the movable throttle lid flow out of the small heating chamber, and upon the inflow of the washer fluid being stopped, the movable throttle lid descends by its own weight and/or a spring force, and during the descent, the washer fluid on a lower side of the movable throttle lid is moved to the upper side of the movable throttle lid via at least any one of a gap between an inner face of the small heating chamber and the movable throttle lid, a gap between an outer face of the electric heater and an inner face of the central hole of the movable throttle lid, and a void formed within a face of the movable throttle lid.   
     
     
         5 . The washer fluid warming device according to  claim 3 ,
 wherein the small heating chamber is formed in a tubular shape extending in a vertical direction;   wherein the washer fluid warming device further includes a plate-shaped movable throttle lid housed in the inner space of the small heating chamber;   wherein the electric heater has a stick-like shape and is arranged along a central axis of the tubular small heating chamber;   wherein the movable throttle lid includes a central hole, and the electric heater is inserted through the central hole and arranged so that the movable throttle lid can ascend/descend along the electric heater, and   wherein upon the movable throttle lid being pushed up by the washer fluid flowing in from a lower portion of the inner space of the small heating chamber, the movable throttle lid makes the washer fluid on an upper side of the movable throttle lid flow out of the small heating chamber, and upon the inflow of the washer fluid being stopped, the movable throttle lid descends by its own weight and/or a spring force, and during the descent, the washer fluid on a lower side of the movable throttle lid is moved to the upper side of the movable throttle lid via at least any one of a gap between an inner face of the small heating chamber and the movable throttle lid, a gap between an outer face of the electric heater and an inner face of the central hole of the movable throttle lid, and a void formed within a face of the movable throttle lid.   
     
     
         6 . The washer fluid warming device according to  claim 4 , wherein a bottom of the tubular small heating chamber is occluded by a plate material in which a throttle port is formed, through which the washer fluid in the inner space of the heat-retaining hot fluid storage chamber flows into the inner space of the small heating chamber. 
     
     
         7 . The washer fluid warming device according to  claim 5 , wherein a bottom of the tubular small heating chamber is occluded by a plate material in which a throttle port is formed, through which the washer fluid in the inner space of the heat-retaining hot fluid storage chamber flows into the inner space of the small heating chamber. 
     
     
         8 . The washer fluid warming device according to  claim 4 , further comprising a washer fluid flow passage in which the washer fluid flows into the inner space of the heat-retaining hot fluid storage chamber from an upper portion of the heat-retaining hot fluid storage chamber and descends in the inner space of the heat-retaining hot fluid storage chamber, and the washer fluid that has descended flows into the inner space of the small heating chamber from a lower portion of the small heating chamber and ascends in the inner space of the small heating chamber. 
     
     
         9 . The washer fluid warming device according to  claim 5 , further comprising a washer fluid flow passage in which the washer fluid flows into the inner space of the heat-retaining hot fluid storage chamber from an upper portion of the heat-retaining hot fluid storage chamber and descends in the inner space of the heat-retaining hot fluid storage chamber, and the washer fluid that has descended flows into the inner space of the small heating chamber from a lower portion of the small heating chamber and ascends in the inner space of the small heating chamber. 
     
     
         10 . The washer fluid warming device according to  claim 6 , further comprising a washer fluid flow passage in which the washer fluid flows into the inner space of the heat-retaining hot fluid storage chamber from an upper portion of the heat-retaining hot fluid storage chamber and descends in the inner space of the heat-retaining hot fluid storage chamber, and the washer fluid that has descended flows into the inner space of the small heating chamber from a lower portion of the small heating chamber and ascends in the inner space of the small heating chamber. 
     
     
         11 . The washer fluid warming device according to  claim 7 , further comprising a washer fluid flow passage in which the washer fluid flows into the inner space of the heat-retaining hot fluid storage chamber from an upper portion of the heat-retaining hot fluid storage chamber and descends in the inner space of the heat-retaining hot fluid storage chamber, and the washer fluid that has descended flows into the inner space of the small heating chamber from a lower portion of the small heating chamber and ascends in the inner space of the small heating chamber.