Claims:CLAIMS
We claim:
1. A Heating Ventilation and Air-Conditioning housing (100A), comprising:
at least one first outlet vent (102) connected to a first fluid passage (102A);
at least one second outlet vent (104) connected to a second fluid passage (104A); and
at least one first door (106) provided at an upstream of the first fluid passage (102A) and the second fluid passage (104A) with respect to the first outlet vent (102) and the second outlet vent (104), wherein the first door (106) selectively opens and closes an inlet area of the first fluid passage (102A) and the second fluid passage (104A), characterized in that,
the Heating Ventilation and Air-Conditioning housing (100A) further comprising a gravitational door (108) provided in the second fluid passage (104A) at the downstream of the first door (106), adapted to close and open the second outlet vent (104), wherein the gravitational door (108) is controlled by a second fluid flow flowing in the second fluid passage (104A).

2. The Heating Ventilation and Air-Conditioning housing (100A) as claimed in claim 1, wherein the gravitational door (108) is provided at the periphery of the second outlet vent (104).

3. The Heating Ventilation and Air-Conditioning housing (100A) as claimed in claim 1 or 2, wherein the gravitational door (108) is in the closed position when the first door (106) opens the first fluid passage (102A) and closes the second fluid passage (104A).

4. The Heating Ventilation and Air-Conditioning housing (100A) as claimed in claim 3, wherein the gravitational door (108) is adapted to open the second outlet vent (104) by the velocity of the second fluid flowing in the second fluid passage (104A) when the first door (106) closes the first fluid passage (102A) and opens the second fluid passage (104A).

5. The Heating Ventilation and Air-Conditioning housing (100A) as claimed in any of the claims 2 to 4, further comprising a foam (202) placed on the periphery of the second outlet vent (104).

6. The Heating Ventilation and Air-Conditioning housing (100A) as claimed in any of the preceding claims, wherein the gravitational door (108) further comprises at least one protruded part (304) adapted to be received in a complementary hole (306) provided on the outer surface of the Heating Ventilation and Air-Conditioning housing (100A) at the second outlet vent (104).

7. The Heating Ventilation and Air-Conditioning housing (100A) as claimed in claim 6, wherein the protruded part (304) further comprises a cut-out portion (304A) adapted to co-operate with a stopper (306A) formed in an outer wall of the complementary hole (306) to restrict movement of the gravitational door (108) beyond a predetermined range of angle.

8. The Heating Ventilation and Air-Conditioning housing (100A) as claimed in any of the preceding claims, wherein the first door (106) is a butterfly door having at least one first part (106A) and a second part (106B); wherein the first part (106A) of the first door (106) is adapted to open and close the first fluid passage (102A) and the second part (106B) of the first door (106) is adapted to open and close the second fluid passage (104A).

9. The Heating Ventilation and Air-Conditioning housing (100A) as claimed in claim 8, wherein the second part (106B) of the first door (106) is adapted to close the second fluid passage (104A), when the first part (106A) of the first door (106) opens the first fluid passage (102A), and the second part (106B) of the first door (106) is adapted to open the second fluid passage (104A), when the first part (106A) of the first door (106) closes the first fluid passage (102A).

10. The Heating Ventilation and Air-Conditioning housing (100A) as claimed in any of the preceding claims, wherein the gravitational door (108) is made of a metal encapsulated by a plastic material. , Description:HEATING VENTILATION AND AIR-CONDITIONING UNIT

Technical Field
The present invention generally relates to a Heating Ventilation and Air-Conditioning (HVAC) unit, more particularly, to an additional door provided in a defrost vent of a HVAC unit to avoid mist formation on windshields of a vehicle during the HVAC unit operating in an air-conditioning (AC) mode.

Background

Generally, vehicles are provided with a heating, ventilation and air-conditioning (HVAC) system to provide conditioned air to the vehicle cabin for comfortable driving experience to passengers. The HVAC system includes a HVAC housing having at least one conditioned air vent and a defrost vent. The conditioned air vent may provide conditioned air, either hot or cold air, to the passenger cabin of the vehicle when the HVAC system is operating in an air-conditioning mode. The defrost vent may provide hot air to the windshields of the vehicle when the HVAC system is operating in a defrost mode. The defrost vent may be connected to a defrost air passage and the conditioned air vent may be connected to a conditioned air passage. Further, a butterfly door is provided in the housing at an upstream of the conditioned air passage and the defrost air passage in such a way that the door selectively close or open the defrost air passage and the conditioned air passage. In air-conditioning mode, the butterfly door may close the defrost passage and open the conditioned air passage to redirect the conditioned air to the conditioned air vent and discharge to the vehicle cabin. In defrost mode, the butterfly door may close the conditioned air passage and open the defrost passage to redirect hot air to the defrost vent and blows the hot air at the windshield.

During air-conditioning mode, the butterfly door closes the defrost air passage to block conditioned airflow into the defrost vent. In case the conditioned air flows into the defrost vent and blows on the windshield, mist/fogging may be formed on the windshield due to temperature difference between inside and outside of the vehicle cabin. Such mist formation may lead to inadequate visibility to the driver that in turn causes severe accidents to the vehicle. Although the butterfly door blocks flow of the conditioned air into the defrost vent, some portion of the conditioned air may escape from the butterfly door and flow into the defrost air passage due to leakage at the butterfly door. Due to such leakage, air may flow through the defrost vent and hit on the windshields that results in mist formation on the windshields. Further, mist formation on the windshields and fogging inside the vehicle cabin may cause severe problems such as lowering visibility to the drivers that may lead to accidents and causing discomfort to the drivers.

Accordingly, there remains a need for an assembly defined in a HVAC housing that blocks flow of conditioned air into a defrost vent when the HVAC is operating in an air-conditioning mode. Further, there remains another need for a HVAC housing having a setup to avoid mist formation on windshields when the HVAC is operating in an air-conditioning mode.

SUMMARY

In the present description, some elements or parameters may be indexed, such as a first element and a second element. In this case, unless stated otherwise, this indexation is only meant to differentiate and name elements which are similar but not identical. No idea of priority should be inferred from such indexation, as these terms may be switched without betraying the invention. Additionally, this indexation does not imply any order in mounting or use of the elements of the invention.

In view of forgoing, the present invention discloses a heating ventilation and air-conditioning (HVAC) housing for a vehicle. The HVAC housing includes at least one first outlet vent, at least one second outlet vent, at least one first door and a gravitational door. The first outlet vent is connected to a first fluid passage and the second outlet vent is connected to a second fluid passage. Further, the first door is provided at an upstream of the first fluid passage and the second fluid passage with respect to the first outlet vent and the second outlet vent. Further, the first door selectively opens and closes an inlet area of the first fluid passage and the second fluid passage. The gravitational door is provided in the second fluid passage at the downstream of the first door, adapted to close and open the second outlet vent and the gravitational door is controlled by a second fluid flow flowing in the second passage.

In one embodiment, the gravitational door is provided at the periphery of the second outlet vent.

Further, the gravitational door is in the closed position when the first door opens the first fluid passage and closes the second fluid passage.

Furthermore, the gravitational door is adapted to open the second outlet vent by the velocity of the second fluid flowing in the second fluid passage when the first door closes the first fluid passage and opens the second fluid passage.

The HVAC housing further includes a foam placed on the periphery of the second outlet vent.

In one embodiment, the gravitational door further includes at least one protruded part adapted to be received in a complementary hole provided on the outer surface of the HVAC housing at the second outlet vent.

Further, the protruded part includes a cut-out portion adapted to co-operate with a stopper formed in an outer wall of the complementary hole to restrict movement of the gravitational door beyond a predetermined range of angle.

In one example, the first door is a butterfly door having at least one first part and a second part. Further, the first part of the first door is adapted to open and close the first fluid passage and the second part of the first door is adapted to open and the second fluid passage.

Further, the second part of the first door is adapted to close the second fluid passage when the first part of the first door opens the first fluid passage. The second part of the first door is adapted to open the second fluid passage when the first part of the first door closes the first fluid passage.

In one embodiment, the gravitational door is made of a metal encapsulated by a plastic material.

BRIEF DESCRIPTION OF DRAWINGS

Other characteristics, details and advantages of the invention can be inferred from the description of the invention hereunder. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying figures, wherein:

Figs. 1A and 1B illustrate schematic views of a Heating Ventilation and Air-Conditioning unit, in accordance with an embodiment of the present invention;

Fig. 2 illustrates a schematic view of a first door provided in a first fluid passage and a second fluid passage of the HVAC unit, along with a gravitational door of Fig. 1A;

Fig. 3 illustrates a perspective view of the gravitational door of Fig. 1A installed on a second outlet vent, wherein the gravitational door is in the closed position; and

Fig. 4 illustrates a schematic view of the gravitational door of Fig. 1A depicting angular movement of the gravitational door between the open and closed positions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It must be noted that the figures disclose the invention in a detailed enough way to be implemented, said figures helping to better define the invention if needs be. The invention should however not be limited to the embodiment disclosed in the description.

The present invention envisages a Heating Ventilation and Air-Conditioning system for a vehicle, hereinafter referred to as HVAC system, having an assembly to block leakage of conditioned airflow into a defrost vent when the HVAC system is operating in an air-conditioning mode. In conventional HVAC systems, some portion of the conditioned air may flow into a defrost vent when the HVAC system is operating in an air-conditioning mode, due to leakages at a door controlling airflow to both the defrost vent and the air conditioning vent. Such leakage of airflow into the defrost vent may hit on the windshields of the vehicle, resulting in mist formation on the windshield. To avoid such problems, a gravitational door is added to the defrost vent at the outlet area of the defrost vent. The gravitational door is adapted to move between an open and closed positions to block the leakage of conditioned air and allow the defrost air. The gravitational door is opened by the velocity of the defrost air flowing into the defrost vent and is closed by the effect of gravity. Geometry and position of the gravitational door are explained with respect to the forthcoming figures.

Fig. 1A and 1B illustrate schematic views of a HVAC unit 100 for a vehicle, in accordance with an embodiment of the present invention. The HVAC unit 100 may include a housing 100A to accommodate various elements of the HVAC unit 100 such as an evaporator, a blower, a heater etc. The housing 100A may include vents to ingress and egress air into/from the housing 100A. Particularly, the housing 100A includes at least one first outlet vent 102 and at least one second outlet vent 104 for discharging air to a passenger cabin. Further, the HVAC unit 100 may further include fresh air inlet and recirculation air inlet (both not shown in Figures). The blower may suck the fluid, for example air, either from the fresh air inlet or recirculation air inlet. Thereafter, the air may be conditioned inside the housing 100A, such as heating up the air or cooling down the air. In this example, cool air is referred to as a first fluid and the heated air is referred to as a second fluid.

Further, the first outlet vent 102 is connected to a first fluid passage 102A for the communication of the first fluid to the first outlet vent 102. The second outlet vent 104 is connected to a second fluid passage 104A for the communication of the second fluid to the second outlet vent 104. Further, the first fluid and the second fluid are fluidically isolated from each other. The housing 100A further includes a first door 106 provided at an upstream of the first fluid passage 102A and the second fluid passage 104A with respect to the first outlet vent 102 and the second outlet vent 104. The first door 106 selectively opens and closes an inlet area of the first fluid passage 102A and the second fluid passage 104A. Particularly, the first door 106 may open and close the inlet area of the first fluid passage 102A to enable and restrict the first fluid flow in the first fluid passage 102A respectively. Similarly, the first door 106 may open and close the inlet area of the second fluid passage 104A to enable and restrict the second fluid flow in the second fluid passage 104A. In this present example, the first door 106 is a butterfly door.

The first door 106 is adapted to simultaneously open and close the first fluid passage 102A and the second fluid passage 104A respectively. In the defrost mode of the HVAC unit 100, the first door 106 is adapted to close the first fluid passage 102A and open the second fluid passage 104A simultaneously. The first door 106 may close the first fluid passage 102A to block the flow of the first fluid into the first fluid passage 102A, simultaneously, the first door 106 may open the second fluid passage 104A to enable the second fluid flow in the second fluid passage 104A. In such case, the second fluid flowing in the second fluid passage 104A may egress from the housing 100A through the second outlet vent 104 and strikes on the windshield of the vehicle.

In the air-conditioning mode of the HVAC unit 100, the first door 106 may close the second fluid passage 104A, and open the first fluid passage 102A simultaneously, to allow the first fluid flow into the first fluid passage 102A. Further, the first fluid flowing in the first fluid passage 102A may egress from the housing 100A through the first outlet vent 102 and enters the passenger’s cabin of the vehicle. In such case, a portion of the first fluid may escape from the first door 106 and leaks/enters into the second fluid passage 104A. Such leakage of cold first fluid into the second fluid passage 104A may egress from the housing 100A through the second outlet vent 104 and strike on the windshield, resulting in mist formation on the windshield.

To avoid such problem, a gravitational door 108 is added to the housing 100A at the second fluid passage 104A. The gravitational door 108 is adapted to close the second outlet vent 104 when the first door 106 opens the first fluid passage 102A. In this present example, the gravitational door 108 is made in such a way that the velocity of the leakage of first fluid flowing in the second fluid passage 104A is unable to open the gravitational door 108. The gravitational door 108 is placed in the second fluid passage 104A at the downstream of the first door 106 and is controlled by the second fluid flowing in the second passage 104A.

Fig. 2 illustrates a schematic view of the first door 106 provided in the first fluid passage 102A and the second fluid passage 104A, along with the gravitational door 108 of Fig. 1A. In one embodiment, the gravitational door 108 is installed at the second outlet vent 104 of the housing 100A, particularly at the periphery of the second outlet vent 104. In another embodiment, the gravitational door 108 is provided in the second fluid passage 104A and in between the second outlet vent 104 and the first door 106. Further, the gravitational door 108 can be provided anywhere in the second fluid passage 104 as long as the gravitational door 108 is downstream to the first door 106.

In the present example, the gravitational door 108 is provided at the periphery of the second outlet vent 104. Generally, the gravitational door 108 is in the closed position, which restricts egressing of the leakage of first fluid from the second outlet vent 104, when the HVAC unit 100 is operating in the air-conditioning mode. Further, velocity of the leakage of the first fluid from the first fluid passage 102A into the second fluid passage 104A is not high enough to open the gravitational door 108. Particularly, velocity of the leakage of first fluid into the second fluid passage 104A is approximately 2 to 2.5m/s, which may be 5% of velocity of the first fluid flowing in the first fluid passage 102A. When the HVAC unit 100 is changed to the defrost mode, the first door 106 may close the first fluid passage 102A and open the second fluid passage 104A, thereby the second fluid may flow into the second fluid passage 104A. Further, the velocity of the second fluid flowing in the second fluid passage 104A may be high enough to open the gravitational door 108. Thereafter, the gravitational door 108 may close the second outlet vent 104 by the effect of the gravity, not linked to any actuator or any other means to actuate the gravitational door 108 to close the second outlet vent 104.

As shown in Fig. 2, the first door 106 is the butterfly door having at least one first part 106A and a second part 106B. The at least one first part 106A, hereinafter referred to as first part, is adapted to close and open the first fluid passage 102A, thereby controlling the first fluid flowing into the first fluid passage 102A. Similarly, the second part 106B is adapted to open and close the second fluid passage 104A, thereby controlling the second fluid flowing into the second fluid passage 104A. In one embodiment, the first part 106A is defined on the first door 106 in such a way the first part 106A is in-line with the first fluid passage 102A and capable of closing the inlet area of the first fluid passage 102A. Similarly, the second part 106B is defined on the first door 106 in such a way that the second part 106B is in-line with the second fluid passage 104A and capable of closing the inlet area of the second fluid passage 104A. In one example, the first part 106A and the second part 106B are flap operationally connected together to form the first door 106. The first part 106A and the second part 106B of the first door 106 are co-axial to each other. As the first part 106A and the second part 106B of the first door 106 are co-axial to each other, the first part 106A may close the first fluid passage 102A and the second part 106B may open the second fluid passage 104A simultaneously, and vice-versa.

Referring to Fig. 2, the first part 106A of the first door 106 closes the first fluid passage 102A to restrict the first fluid flow into the first fluid passage 102A and the second part 106B of the first door 106 opens the second fluid passage 104A to allow the second fluid flow into the second fluid passage 104A. Therefore, the velocity of the second fluid flowing in the second fluid passage 104A opens the gravitational door 108, so that the second fluid may egress from the housing 100A through the second outlet vent 104. Further, a foam 202 is placed on the periphery of the second outlet vent 104 to enable fluid-tight sealing between the gravitational door 108 and the second outlet vent 104. When the second part 106B of the first door 106 closes the second fluid passage 104A, the gravitational door 108 is moved to the closed position and closes the second outlet vent 104, so the leakage of first fluid flowing in the second fluid passage 104A may not egress from the second outlet vent 104. As the foam 202 is provided in between the gravitational door 108 and the second outlet vent 104, the gravitational door 108 may effectively block egressing of the first fluid from the second outlet vent 104.

Fig. 3 illustrates a perspective view of the gravitational door 108 of Fig. 1A installed on the second outlet vent 104, wherein the gravitational door 108 is in the closed position. The gravitational door 108 further includes a protruded part 304 formed at both ends of a lateral side of the gravitational door 108. The protruded part 304 is connected to any receiving means provided on the housing 100A to act as pivot to move the gravitational door 108 between the open and closed positions. The housing 100A further includes a complementary hole 306 formed on the outer surface of the housing 100A at the second outlet vent 104. Further, the protruded part 304 is adapted to be received in the complementary hole 306 formed on the housing 100A, so that the gravitational door 108 may move between the open and closed positions with the protruded part 304 and the complementary hole 306 acting as pivot to the gravitational door 108. In one embodiment, the diameter of the protruded part 304 is substantially same as the diameter of the complementary hole 306, particularly smaller than that of the diameter of the complementary hole 306, so that the protruded part 304 can be received in the complementary hole 306 formed on the housing 100A.

As shown in Fig. 3, the protruded part 304 further includes a cut-out portion 304A protruded out, along a longitudinal axis of the protruded part 304. The cut-out portion 304A is adapted to deform, while the protruded part 304 is inserted into the complementary hole 306 formed on the housing 100A. Upon receiving the protruded part 304 into the complementary hole 306, the cut-out portion 304A returns back to its normal position to retain the protruded part 304 in the complementary hole 306. Further, the complementary hole 306 includes a stopper 306A adapted to co-operate with the cut-out portion 304A of the protruded part 304 to restrict angular movement of the gravitational door 108 beyond a predetermined range of angle.

Fig. 4 illustrates a schematic view of the gravitational door 108 of Fig. 1A depicting angular movement of the gravitational door 108 between the open and closed positions. As shown in Fig. 4, the stopper 306A formed on the outer wall of the complementary hole 306 restricts angular movement of the protruded part 304 beyond a predetermined range, thereby restricting movement of the gravitational door 108. In this embodiment, the angular movement of the gravitational door 108 with respect to the second outlet vent 104 is in between 0 to 55 deg. As shown in Fig. 4, the cut-out portion 304A is adapted to angularly move in the complementary hole 306, thereby moving the gravitational door 108 between the open and closed positions.

As the stopper 306A is provided in the complementary hole 306, the cut-out portion 304A may not angularly move beyond the predetermined range. In this embodiment, the gravitational door 108 is made of a metal encapsulated by a plastic material. As the plastic material is encapsulated on the gravitational door 108 and is in-contact with the foam 202 present in the second outlet vent 104, the gravitational door 108 may effectively block egressing of the first fluid from the second outlet vent 104 when the first door 106 allows the first fluid entering into the first fluid passage 102A and blocks the second fluid entering into the second fluid passage 104A. Therefore, the cold first fluid may not egress from the second outlet vent 104, thereby avoiding mist formation on the windshield of the vehicle.

In any case, the invention cannot and should not be limited to the embodiments specifically described in this document, as other embodiments might exist. The invention shall spread to any equivalent means and any technically operating combination of means.