DESC:FIELD OF THE INVENTION
[0001] The present invention relates to a vehicle ventilation system, and more particularly to a vehicle ventilation system for windscreen demisting and for improving cabin ventilation.
BACKGROUND TO THE INVENTION
[0002] During the cold weather and high humidity conditions (mostly during rains) when there is temperature difference inside the passenger compartment and outside the vehicle, mist gets formed on windscreen inner surface due to condensation of high moisture content in environment. This creates obstruction in driver front visibility and can cause accidents if not cleared.
[0003] It is observed that in spite of demisting system installed in many of the vehicles, due to its undesired performance, often drivers help themselves to clear the windscreen faster by bringing down the windows momentarily, thereby allowing the outside air to rush into the cabin and thereby reducing the amount of water vapour inside the car. But the driver suffers exposure to cold weather by such an act. The invention has devised an arrangement to design intelligent system which system uses the principle of allowing external air into the cabin but the driver shall not suffer exposure to outside weather.
[0004] Typically for demisting of the windscreen, heated air is used. The heat required for producing heated air is generally obtained from vehicle’s engine coolant and may be through heater core. Fresh air is blown through this heater core and then ducted to take the path into the interior of the vehicle. Blower is used for distribution of the air over the interior surface of the windscreen.
[0005] In other known art, air is made to pass through vehicle’s operating air conditioning evaporator. This dehumidifies the air thereby enhancing the speed and quantum of defogging as drier air tends to absorb more water from the glass / panel to which it is directed. In another aspect, defoggers of prior art may also be equipped with automatic timers, which switch OFF the system after a set period, within which period the defogging is achieved i.e. when the vehicle’s heater has brought the interior of the vehicle to a warm enough temperature that the fog does not recur.
[0006] In most of the four wheeled vehicles, demisting of windscreen is achieved by means of an electrical blower or a heating element or combination of both. In such systems, there is a high level of dependence on external source of energy and power and manual intervention for the system to operate efficiently and effectively.
[0007] As explained earlier, some vehicles use engine exhaust heat for increasing air temperature and direct it towards windscreen with the help of electrical Fan/ blower to demist the windscreen using control logics and or uses this hot air for cabin heating/ ventilation. Even such systems, involves electrical and actuation means for operation and control.
[0008] An automotive air-conditioning apparatus according to US patent number 4685508 has an air blower and an air mixing damper for adjusting the ratio of a mixture of cool air and hot air. The temperature of air in the automobile cabin is controlled dependent on the amount of air fed from the air blower and the opening of the air mixing damper. In a demisting mode, the amount of air from the air blower is greater than that in a normal temperature adjusting mode, and the opening of the air mixing damper is controlled depending on ambient-air conditions.
[0009] A demisting device on the inner side of a windscreen according to CN 202863395 U comprises a demisting driving motor assembly and a demisting device switch. The demisting driving motor assembly and the demisting device switch are fixed on a vehicle body. The demisting device on the inner side of the windscreen further comprises a demisting bar and a demisting bar fixing support, wherein the demisting bar is made of soft water absorbing materials and is tightly attached to the inner side surface of the windscreen, and the demisting bar fixing support is used for fixing the demisting bar. The demisting bar fixing support comprises a demisting bar fixing part and a motor connection part. One end of the motor connection part is fixedly connected with one end of an output shaft of the demisting driving motor assembly. The other end of the motor connection part is connected with one end of the demisting bar fixing part in a hinged mode. A tension mechanism used for enabling the demisting bar to be tightly attached to the inner side surface of the windscreen is arranged between the demisting bar fixing part and the motor connection part. The demisting device on the inner side of the windscreen is capable of removing the mist attached to the inner side of the windscreen of a vehicle and has the advantages of being fast, reliable, and capable of quickly removing the mist attached on the inner side of the windscreen and facilitating improvement of driving safety.
[0010] Thus, the known prior art systems typically employ
- A typical windscreen demisting system using costly electrical blower unit, and / or
- Using costly heating elements and / or
- Using costly plastic ducting or tubular sheet metal pipe ducting to direct air on windscreen.
[0011] Known prior arts employs external source of energy and manual intervention for cabin ventilation of vehicle. Driver needs to watch and make sure that heater blast of air conditioning unit is switched ON and directed at the windscreen. So there is a need to dry out the air consciously within the vehicle by the driver. Thus manual intervention is needed to make the system work effectively. Further, the temperature needs to be increase gradually as the air dries out. If the temperature is increased rapidly, it will lead to a hot wet air inside the cabin.
[0012] All known prior arts rely on one or other manual operation means for coping with fogging of windscreen in a vehicle. Such systems solve problem of improving visibility to the driver but need manual intervention to activate the system. Such systems can be a potential safety hazard as they detract driver from watching road condition as driver has to keep taking measures to prevent fogging of the windscreen while continuing to drive the vehicle.
[0013] The prior art suffers many such disadvantages as the driver has to consciously operate the system carefully causing discomfort and potential safety hazard to the driver of the vehicle.
OBJECTIVES OF THE INVENTION
[0014] Object of the present invention is to provide a cost effective, light weight windscreen demisting and cabin ventilation solution.
[0015] Another object of the present invention is to achieve demisting of windscreen and cabin ventilation without addition of electrical blower or air conditioning system or any cabin conditioning system.
[0016] Another object of the present invention is use of the operating parameters of the vehicle such as natural RAM air flow due to vehicle movement in forward direction for windscreen demisting and cabin ventilation instead of using any external power source or any external activation source or any electrical device (like fan/ blower/ AC) or dedicated plastic duct.
[0017] Another object of the present invention is to use the vehicle body itself as path of air travel for directing captured air towards windscreen or passengers to save cost.
[0018] Another object of the present invention is to use vehicle motion as actuation means without driver intervention for demisting of windscreen and cabin ventilation.
[0019] Another object of the present invention is to provide a self-operating and self-actuating system for demisting of windscreen and cabin ventilation without need of external powered means.
SUMMARY OF THE INVENTION
[0020] In cold weather, drivers suffer due to a foggy windscreen. Mist formation on windscreen in an automotive enclosed vehicle happens mainly due to temperature difference between inside and outside of the vehicle in high humid conditions. Generally the windscreen fogs when driver/passengers enter the vehicle. Body temperature of driver/passengers warms the inside air. Further, there is additional warm moist air created by breathing of driver/passengers, which further increases humidity inside the vehicle. As air trapped within the closed vehicle is generally more humid and warm than the outside air, it tends to hold more moisture. When the car is driven, warmer air created inside the cabin gets in contact with the colder glass of windscreen and loses some of its ability to hold the moisture as it cools down. Excess water vapour which air inside cabin cannot hold condenses onto the glass leading to fogging of the windscreen.
[0021] The device and the method as per invention utilize a means to capture atmospheric air intelligently during motion of vehicle and diverting it into the cabin selectively through the created pathways within the vehicle with exit points, instead of relying on external electrical means for actuation.
[0022] In the current invention demisting of windscreen is achieved by directing outside relatively cool air in comparison to inside air directly on windscreen. The invention teaches a method to retain the cabin temperature at a temperature at which the maximum amount of water vapour can be held in the air within the cabin at given pressure before condensing into a liquid. Also current invention alternatively helps in cabin ventilation when the windows/doors are closed and vehicle is running.
[0023] In one aspect of the invention, openings are provided in the front panel of the vehicle. RAM air enters the front body structure through these openings and is then directed through body panel’s to “A pillar”. Opening provided on A pillar inner side on either left hand or right hand side or both sides of windscreen. Air entering from front panel enters the vehicle cabin through the openings provided on A pillar inner side. A flap is provided at the opening on the A pillar which opens into the cabin. The flap can be adjusted to direct the entering air into the cabin in direction towards windscreen or towards passengers or it can even close the opening to close the air entry into cabin.
[0024] As vehicles moves forward, air pressure on front BIW panels increases with vehicle speed and RAM air starts entering in the vehicle and guided on windscreen inner fame. Relatively low temperature outside air flow on windscreen helps in eliminating the accumulated moisture by natural evaporation.
[0025] In the invention an attempt is made to create comfortable cabin environment by allowing continuous flow of fresh air through the cabin when the vehicle is moving and further the air movement is assisted merely by creating a novel passage way between atmosphere and the cabin for the purpose of demisting the windscreen and for purpose of cabin ventilation.
[0026] By the virtue of mechanism provided in this invention, due to vehicular movement, the RAM air flow of outside air (which is having low temperature as compared to inside air temperature) can be directed on inner surface of windscreen. This helps in removing the accumulated mist on windscreen and will also prevent mist formation during further running of the vehicle.
[0027] Alternatively with the same mechanism, RAM air can also be alternatively directed towards driver and co-driver body. This helps in cabin ventilation when doors and windows are closed. As per the invention there is no need for the driver to manually control the various known components of interior air control system such as a heater, blower, cooler, defroster and the like to eliminate the misting/fogging when it occurs in a cabin of the vehicle, as suffered in the prior art. Further, the invention eliminates the need for the above mentioned components to achieve demisting.
[0028] In any operation of demisting devices known from prior art, driver’s attention is distracted for activation and deactivation. But the invention is aimed at lowering the distraction of the driver as minimal as it can get. This prevents possibilities of accident while driving on the road. The invention achieves to provide a device and a method for automatically preventing misting of the vehicle windscreen.
[0029] Other features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS
REFERENCE NUMBER TABLE
No. Feature
1 Grill
2 Inclined surface of front panel
3 Openings provided on front panel
4 Front panel
5 Air flow path entering front panel
6 Fender section
7 A pillar upper part
8 Openings provided on A pillar upper part
9 Windscreen frame
10 Plastic cover flap
11 A pillar bottom part
12 Openings provided on A pillar bottom part
13 Air escape opening in front firewall
14 Air escape openings in side window grill
15a Air entry openings in C pillar inner
15b Air exit openings in C pillar outer
[0030] Figure 1 illustrates isometric view of a vehicle front outer side with a grill.
[0031] Figure 2 illustrates isometric view of a vehicle front outer side providing grill details.
[0032] Figure 3 illustrates front view of a vehicle front outer side providing grill details.
[0033] Figure 4 illustrates RAM air entering direction through front grill in BIW box section.
[0034] Figure 5 illustrates RAM air distribution through front grill in BIW Left Hand and Right Hand fender section.
[0035] Figure 6 illustrates RAM air travelling path details in front view of a vehicle front outer side.
[0036] Figure 7 illustrates RAM air travelling path details in side view of a vehicle front outer side.
[0037] Figure 8 illustrates RAM air travelling path details within vehicle cabin front side.
[0038] Figure 9 illustrates three different flap positions on a cabin pillar viz. towards windscreen, towards occupants and flap closed.
[0039] Figure 10 illustrates plastic flap orientation towards windscreen in section view.
[0040] Figure 11 illustrates plastic flap orientation towards occupants in section view.
[0041] Figure 12 illustrates plastic flap closed position stoping air flow in section view.
[0042] Figure 13 illustrates an alternative arrangement for air entry where opening for air entry given on A pillar lower side instead of A pillar upper side.
[0043] Figure 14 illustrates zoom view of an alternative arrangement for air entry where opening for air entry given on A pillar lower side instead of A pillar upper side.
[0044] Figure 15 illustrates an alternative arrangement where air escape path provided in front firewall in case of complete enclosed sealed vehicles for better air circulation efficiency.
[0045] Figure 16 illustrates an inner view of an alternative arrangement where air escape path provided in side window grill and Cutout provided in C pillar inner in case of complete enclosed sealed vehicles for better air circulation efficiency.
[0046] Figure 17 illustrates an outside view of an alternative arrangement where air escape path provided in side window grill and Cutout provided in C pillar outer.

DETAILED DESCRIPTION
[0047] In first embodiment as illustrated in the figures 1 to 6, openings 3 are provided on front panel 4. Most preferably the openings 3 are provided on the inclined surface 2 toward front. The openings can be integrated in vehicle styling. The openings 3 provided on inclined surface 2 helps in preventing direct water entry in rainy season or during vehicle washing. The openings 3 in front BIW (Body in White) panel 4 is illustrated in figure 1. Grill 1 may also be integrated in BIW front panel sheet metal parts. For such integrated arrangement, there is a need for formed parts with cutouts. This helps in reducing cost as no additional parts like plastic or wire mesh is required.
[0048] Figure 2 and 3 illustrates detail view of grill 1 in BIW front panel 4. Front grill with cutouts is provided at an optimum angle of 30 degree from vertical. This angular position helps in directing air towards further air travel path. The current invention takes advantage of providing the opening on high pressure area, from where RAM air enters in the front panel 4 (Figure 4). Figure 5 illustrates the path 5 of air which is entering from front panel 4 and distribution paths in left hand and right hand side fender section 6.
[0049] Right Hand/Left Hand front fender sections 6 are connected with A pillar upper 7 and is part of windscreen frame 9. Air entering from grill 1 is guided through front fender section 6 upto A pillar upper 7. An opening 8 is provided on A pillar upper 7. Air enters into the cabin through the opening 8 on A pillar upper 7. Figure 6 and 7 illustrates the details.
[0050] A control means is disposed in the pathway between the capturing point of the atmospheric air and the point of entry of the atmospheric air into the cabin. The aim of the control means is to guide and control the air from the pathway into the cabin. The control means can be a plastic cover flap 10 disposed in the BIW cutout opening 8 on A pillar upper 7. The plastic cover flap helps in guiding air in desired direction. The positions of the flap can be adjusted to change the direction of the air flow. . The flap can be positioned in at least three states i.e. either it can be guide air towards windscreen or towards occupants or it can close the air vent so no air would enter into the cabin. Thus the plastic flap works as on-off cover as well as works as air guide as shown in figure 9.
[0051] The air is entering from front panel 4, can be guided with the help of BIW section and moved through A pillar upper cutout 8 into the cabin. The air can be directed towards windscreen with the help of the plastic flap cover described above. As vehicles moves forward the, air pressure on front BIW panels 4 increases, as the vehicle speed increases. RAM air starts entering into the vehicle and is guided on the windscreen inner frame as described above. As the outside air has relatively low temperature and low humidity, it eliminates mist/fog formed on windscreen. Further, it assists in reducing further mist/fog formation on windscreen.
[0052] There are many embodiments that can be envisaged based on the principles disclosed above. Though the invention is not limited to embodiments described.
1. In another embodiment instead of cutout given on front BIW panel, cutout can also be provided either on side fenders or on A pillar outer itself, and external air can enter inside the BIW section through this path.
2. In another embodiment, instead of cutout given on A pillar upper inner side, cutout 12 can also be provided on A pillar bottom parts 11 (Figure 13 and Figure 14). In this case it can work only as ventilation path and fails to be effective in windscreen demisting.
3. In another embodiment, an air escape opening arrangement can be provided in automotive vehicles which are completely enclosed and sealed with no openings for air escape. In such cases, addition of the air escape opening in vehicle may improve efficiency due to streamlined air flow inside the vehicle from front to rear. As shown in figure 15, the air escape opening (13a) arrangement can be provided in front firewall. In an alternative arrangement, the air escape openings (14) are provided on side window grill. Opening (14) provided on inside of the grill directly connect the outside environment. In another alternative arrangement, air escape arrangement includes air entry openings (15a) provided on C pillar inner and air exit openings (15b) provided on C pillar outer. Air entering from openings (15a) goes into C pillar box section from where it escapes to outside environment through the exit openings (15b) provided in C pillar outer. Above mentioned air escape arrangements can be adopted independently or in combination thereof.
[0053] The system explained above is very compact and can be integrated within the vehicle easily. Further, the system can be conveniently operated, cost effective and not energy dependant.
[0054] By adopting the proposed system, the driver’s visibility is improved and improved condition is maintained in the cabin of the vehicle continuously as the vehicle is moving. The system is not dependence on any external source of energy as heated air is not used for demisting of the windscreen glass and thereby temperature of interior of vehicle is not heated up which is typical in conventional system. On the other hand the invention does manage to reduce the moisture from the air within the cabin simply by introducing atmospheric air continuously but selectively into the cabin. Introduction of the atmospheric air is also done without any external power source but by using the very motion of the vehicle itself. In this arrangement, the temperature of inside surface of the windshield is always maintained at a temperature almost equal to temperature outside the vehicle, thereby continuously clearing the condensation that may occur on inner surface of windshield.
[0055] The description is typically focused to explain details with respect to demisting/defogging of windscreen of the vehicle. However, the invention can be extended to use the same principle and arrangement with obvious modifications to demist / defog rear glass, and/or side windows of a vehicle also.
[0056] Keeping the arrangements of the components in mind, which are mechanical in nature and which generally operate as per the conditions surrounding them, the driver need not operate any air conditioning system or heater system to demist screen. Further, the visibility through the windscreen is remedied rapidly as the volume of air entering the cabin is dependant only on speed of vehicle and the control means mounted thereon on the vehicle. In spite of the rapid action of the demisting, the driver will not be exposed to the outside temperature.
[0057] As per invention, prevention of demisting of windscreen and humidity control inside the vehicle cabin can be performed automatically on the basis of the speed of vehicle, and also control of entry of atmospheric air into cabin selectively through novel passage arrangement and entry arrangements of the atmospheric air into the cabin. The system and method frees the driver from any troublesome and dangerous manual operation of demisting control means.
[0058] All variations and modifications that are obvious to skilled persons are well covered within the scope of the invention. As described above, due to its simple principle applied and due to easy arrangement identified in the invention, the invention is susceptible of multiple physical embodiments, beyond what has been explicitly put forth in specification and all such embodiments will perform in satisfactory manner and thereby all are within the scope and spirit of the invention.
,CLAIMS:1. A vehicle ventilation system for demisting windscreen and for improving cabin ventilation comprising:
a. air intake openings on the vehicle for introducing atmospheric air into the body structure of the vehicle,
b. a pair of pillars disposed within body structure of the vehicle one on each side of the windscreen of the vehicle forming a passage for drawing the atmospheric air entering through the air intake openings towards the cabin of the vehicle,
c. a ventilating means provided on at least one pillar and opening into the cabin, and
d. a control means disposed on the ventilating means for selectively opening and closing the ventilating means into the cabin and selectively varying the direction of the opening towards the windscreen or away from the windscreen within the cabin thereby controlling the air fed into the cabin and change the flow direction of air into the cabin.
2. The vehicle ventilation system as claimed in claim 1, wherein air intake openings are disposed in the front panel of the vehicle.
3. The vehicle ventilation system as claimed in claim 1, wherein the air intake openings are disposed on the pillars and where the air intake openings are integral with pillars.
4. The vehicle ventilation system as claimed in claim 1, wherein the air intake openings are disposed on side fenders of the vehicle and where the air intake openings may be integral with the side fenders.
5. The vehicle ventilation system according to any of the preceding claims, wherein the air intake openings are preferably disposed on an inclined surface portion of the vehicle.
6. The vehicle ventilation system as claimed in claim 1, wherein the air intake openings includes a grill means, preferably arranged inclined to floor surface of the vehicle and most preferably opening is inclined at 30° from vehicle vertical.
7. The vehicle ventilation system as claimed in claim 1, wherein a control means can be a cover flap.
8. The vehicle ventilation system as claimed in claim 7 wherein the cover flap can be adjusted to set a plurality of open modes for selectively opening the flap towards the windscreen and away from the wind screen at different angles within the cabin and a close mode to stop entry of the air.
9. The vehicle ventilation system as claimed in claim 1, the system further comprises an air escape opening arrangement.
10. The vehicle ventilation system as claimed in claim 9, wherein said air escape opening arrangement (13) is provided in front firewall or in side window grill (14).
11. The vehicle ventilation system as claimed in claim 9, wherein said air escape opening arrangement includes air entry openings provided on C pillar inner (15a) and air exit openings provided on C pillar outer (15b).
12. The vehicle ventilation system as claimed in claim 9, wherein said air escape opening arrangement can be any combination of the air escape opening arrangement mentioned in claim 10 and 11.
13. A method of demisting windscreen and improving cabin ventilation of a vehicle comprising the steps of :
a. capturing atmospheric air through air intake openings on the vehicle for introducing atmospheric air into a body structure of the vehicle,
b. passing air through a pair of pillars disposed within the body structure of the vehicle one on each side of a windscreen of the vehicle forming a passage for drawing the atmospheric air entering through the air intake openings towards a cabin of the vehicle,
c. channelizing the atmospheric air further into the cabin through a ventilation means provided on at least one pillar and opening into the cabin, and
d. directing the air in a specific direction into the cabin by a control means disposed on the ventilating means for selectively opening and closing the ventilating means into the cabin and selectively varying the direction of the opening towards the windscreen or away from the windscreen within the cabin thereby controlling the air fed into the cabin and change the flow direction of air into the cabin.
14. A method of demisting windscreen and improving cabin ventilation of a vehicle as claimed in claim 13 further comprising steps of providing air escape arrangements by channelizing air through air escape opening provided on front fire wall or side window grill or by channelizing air entry through entry opening provided on C pillar inner and then channelizing air through exit opening provided on C pillar outer