FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
SINGLE FLAP ACTUATION FOR HVAC TEMPERATURE
REGULATION
BEHR INDIA LIMITED
an Indian Company of Gate No.626/1/2 & 622/1/0,29 Milestone, Pune-Nasik Highway, Village - Kuruli, Taluk - Khed, Pune - 410501, Maharashtra, India.
NAME OF THE INVENTORS
1. PARTHASARATHIGARIKIPATI
2. SURAJ SATHYANARAYAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

FIELD OF THE DISCLOSURE
The present disclosure generally relates to HVAC (Heating, Ventilation and Air Conditioning) systems.
Particularly, the present disclosure relates to temperature regulation of air in HVAC systems.
BACKGROUND
Heating, ventilation, and air conditioning (HVAC) systems are used in various applications such as but not limited to indoor or automotive environmental comfort. HVAC systems play an important role in the design of automobiles, medium to large industrial and office buildings, marine environments such as aquariums and the like. HVAC systems are designed for regulating temperature, humidity, as well as fresh air inside automobiles, buildings, and marine environments for maintaining comfortable, safe and healthy conditions therein.
In HVAC systems, 'mixed temperature' condition of air is widely required. The mixing of cold / ambient air takes place in a space wherein opening / closing is controlled with louvers or valves. In case of automotive air-conditioning, with the trend of more compact and cost effective vehicles, the space available is shrinking day by day.

Accordingly, there is a need for 'a system that is effective and provides better space utilization by controlling the mixing of cold air from an evaporator and hot air from a heater in a limited space available in a cost effective way.
OBJECTS
Some of the objects of the present disclosure which at least one embodiment is adapted to provide, are described herein below:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a single flap actuation system for HVAC temperature regulation that controls the mixing of cold air from an evaporator and hot air from a heater.
Another object of the present disclosure is to provide a single flap actuation system for HVAC temperature regulation that controls the mixing of cold air from an evaporator and hot air from a heater in a cost effective way.
Yet another object of the present disclosure is to provide a single flap actuation system for HVAC temperature regulation that provides improved space utilization when controlling the mixing of cold air from an evaporator and hot air from a heater.
Further, an object of the present disclosure is to provide a single flap actuation system for HVAC temperature regulation that is simple in structure.

SUMMARY
In accordance with the present disclosure, there is provided an HVAC system comprising an air blower and a heater disposed operatively before and after an evaporator respectively,
the system characterized in that:
• the heater is disposed in a position inclined to the horizontal plane;
• a flap is disposed operatively between the evaporator and the heater; a portion of the flap defining a spoiler to selectively control mixing of air from the heater and the evaporator; and
• actuator means is provided which is adapted to co-operate with the flap to selectively move the flap between a closed position, an intermediate position and an open position, the closed position defines a cold air flow from the evaporator to a distribution channel, the open position defines a hot air flow from the heater to a distribution channel and the intermediate position defines a warm air flow wherein a mixture of cold air from the evaporator and hot air from the heater are mixed to attain a pre-determined temperature.
Typically, the actuator means co-operates with a temperature sensor.
Typically, the actuator means is controlled by at least one of a manual and automated means or a combination thereof.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS;
The single flap actuation system of the present disclosure will now be explained in relation to the accompanying drawings, in which:
Figure 1 illustrates a general arrangement of an HVAC (Heating, Ventilation and Air Conditioning) system known in the art including two flaps;
Figure 2 illustrates a schematic representation of air path in the HVAC system of Figure 1;
Figure 3 illustrates a general arrangement of a single flap actuation system in an HVAC system for temperature regulation, in accordance with an embodiment of the present disclosure;
Figure 4 illustrates a general arrangement of a single flap actuation system in the HVAC system of Figure 3, when the flap is in a closed position;
Figure 5 illustrates a general arrangement of a single flap actuation system in the HVAC system of Figure 3, when the flap is in an open position;
Figure 6 illustrates air flow path when the when the flap of the HVAC system of Figure 3 is in a closed position;
Figure 7 illustrates air flow path when the flap of the HVAC system of Figure 3 is in an open position; and

Figure 8 illustrates a perspective view of the single flap actuation system in the HVAC system of Figure 3.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The single flap actuation system will now be described with reference to the accompanying drawings which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The single flap actuation system of the present disclosure provides a single flap for controlling the mixing of cold air from an evaporator and hot air from a heater in a limited space available in a cost effective manner. The HVAC systems known in the art typically employ at least two flaps for temperature regulation which not only make the system bulky, but also add on to the cost of the system. The single flap actuation system of the present disclosure is simple in construction and provides HVAC temperature regulation effectively. The single flap actuation

system of the present disclosure may be controlled manually by use of kinematic linkages or may be controlled automatically by use of an actuator motor.
Figure 1 illustrates a general arrangement of an HVAC (Heating, Ventilation and Air Conditioning) system known in the art including two flaps. An air conditioning system typically includes an evaporator, a heater, an expansion valve, a temperature mix louver and a distribution louver compactly arranged in a single distribution housing. An air blower 102 is a primary source of air flow for the HVAC system. Conventionally, the blower 102 is located operatively before an evaporator 126. A heating chamber space 112 is separated from the evaporator area by two flaps, a primary mixing flap 104 and a secondary mixing flap 106. In a cold mode condition, the secondary mixing flap 106 touches housing stoppers 108 and 110 thus preventing air from the evaporator 126 from entering into the heating chamber space 112. The primary mixing flap 104, stoppers 114 and 116 abut housing stoppers 118 and 120 respectively, thus restricting hot air from the heater chamber area 122 from entering into a mixing area 124. Cold air from the evaporator 126 moves directly into the mixing area 124 through a space 128 and an opening 130. This cold air is then distributed to respective outlets through a distribution channel 132.
In a hot mode, the secondary mixing flap 106 moves away from the housing stoppers 108 and 110, allowing cold air to move from the cold area 128 to the heater chamber area 122. The secondary mixing flap 106, at this moment, is in the second position i.e. the flap stoppers 114 and 116 abut the housing stoppers 120 and 118. Air from the heating chamber space 112 passes through the heater and gets heated. Hot air passes through the heater chamber area 122 directly into the mixing chamber 124. This air is further distributed to the respective outlet through

the distribution channel 132. Partial opening of the primary mixing flap 104 and secondary mixing flap 106 permits a proportionate mixing of cold air and hot air in the mixing chamber 124 to maintain desired temperature at the distribution outlet 132.
Cold air Path -> Blower Area 102 - Evaporator 126 - Cold Air Area 128 -Channel 130 - Mixing Area 124 - Distribution channel 132
Hot air path -> Blower Area 102 - Evaporator 126 - Cold Air Area 128 - Heating chamber space 112 - Heater 136 - heater chamber area 122 - Mixing Area 124 -Distribution channel 132
Figure 2 illustrates a schematic representation of air path in the HVAC system of Figure 1.
Figure 3 illustrates a general arrangement of a single flap actuation system in an HVAC system for temperature regulation, in accordance with an embodiment of the present disclosure. An air blower 202 is generally located before an evaporator 204. A heater 206 is placed after the evaporator 204. The heater 206 is inclined to the horizontal plane. The large area located operatively above the heater core where the flaps are located is a distribution channel 208; the air is diverted to various openings through this distribution channel 208. The distribution channel 208 typically consists of a foot flap controlling the foot air flap and face/defrost flap controlling the face and defrost air flow.
Further, a temperature flap 220 is disposed after the heater core. A part of this flap extends below the heater 206. In this arrangement, the complete heater chamber is

formed by enclosing the heater core in between the flap and the distribution housing. The top portion 210 of the flap completely closes and opens a mixing space 212 after the heater 206. The extended portion of the flap acts more as a flap spoiler 214, by preventing air from the evaporator 204 from directly entering the heater chamber 216 when the flap is in a closed position.
Figure 4 illustrates a general arrangement of a single flap actuation system in the HVAC system of Figure 3, when the flap is in a closed position. In this condition, the heater 206 is completely enclosed in the heater chamber 216. The flap spoiler 214 restricts air moving from an evaporator exit area 218 from entering into the heater chamber 216. This avoids cold air from coming in contact with the hot air. The flap 220 also closes the portion operatively above the heater 206. This avoids the space operatively above the heater 206 from coming in contact with the air flow path. In this position of the flap 220, a gap is created from the operative top of the flap to the evaporator area for cold air passage 222. Hence the cold and dehumidified air leaving the evaporator into the area 218 directly comes in contact with the mixing space 212. This leads to the cold and dehumidified air flowing directly into the distribution channel 208. The heater chamber 216 is completely isolated from the air flow path.
The path taken by the air flow is as follows:
Blower 202 — Evaporator 204 — Evaporator exit space 218 — Cold air passage
222 — Mixing Space 212 — Distribution channel 208.
Figure 5 illustrates a general arrangement of a single flap actuation system in the HVAC system of Figure 3, when the flap is in an open position. In this position the flap touches an upper end stopper 224. The spoiler portion being an integrated

structure of the flap also gets lifted. The evaporator exit space 218 is directly connected to the heater chamber 216. The air coming from the evaporator can freely move to the heater core. The flap spoiler 214 closes the cold air passage 222 and thus isolates the mixing space 212 directly coming in contact with the evaporator exit space 218. This prevents the air flowing out of the evaporator from directly entering the mixing space 212. All the air coming from the evaporator is now necessarily required to pass through the heater. The cold and dehumidified air coming out of the evaporator then comes in contact with the heater resulting in hot air at the exit of the heater core i.e. space 226.
Figures 6 and 7 illustrate air flow path when the when the flap of the HVAC system of Figure 3 is in a closed position and an open position respectively. The distribution housing consists of side pockets 228A and 228B. In the Figures 6 and 7, "A" refers to cold air passage, "B" refers to cold air exit and "C" refers to warm air exit. The temperature mixing flap 220 moves between the side pockets as illustrated in the Figures. In a cold position, the flap 220 touches the portion of the housing i.e. the stopper 230. The top portion of the space 232 is completely sealed by the flap 220. This isolates the space 232 from the mixing space 212. The air from the evaporator directly enters the mixing space and is directed to a distribution channel. The air entering the distribution channel is completely cold.
In order to get warm air at the distribution outlet it is required to lift the flap 220 upwards as illustrated in Figure 7. The flap 220 moves away from the stopper 230. This increases the space 232 located operatively above the heater. As the flap gets lifted, it also facilitates flow of air from the space 232 to the mixing space 212 thorough the distribution housing side pockets 228A and 228B. Since the flap 220 rests over the stopper 224 on the top side and the spoiler 214 blocks the cold air

passage 222, the movement of cold air directly into the mixing space 212 is completely restricted. The warm air then flows through the distribution channels which direct the warm air as per requirement.
The following would be the airflow path for the complete warm air mode, y
Blower 202 — Evaporator 204 — Evaporator exit space 218 — Heating chamber 216 — Heater Core 206 — heater top space 232 — Side Pocket 228A and 228B — Mixing Space 212 — Distribution channel 208.
Further, for achieving an intermediate desired temperature condition, cold air from the evaporator and hot air from the heater are required to be suitably mixed. In such conditions, the flap 220 is positioned in an intermediate position between complete cold mode and complete hot mode i.e. the flap would be away from both the upper stopper 224 and the lower stopper 230. The cold air passage 222 and the hot air passage 232 would respectively increase and decrease based on the flap position. The cold air from the evaporator space 218 moves into the mixing space 212 through the cold air passage. Simultaneously, warm air moving out of the heater enters into the mixing space 212 through the hot air passage 232 and distribution housing side pockets 228A and 228B. Hence in the mixing space 212 there would be a mixing of cold air and warm air resulting in air having a desired temperature, the resulting air can be further distributed through the distribution channel.
The position of the flap decides the amount of cold air and amount of hot air entering the mixing space 212. The flap movement from the lower stopper to the

upper stopper results in air temperature variation from a complete cold to a complete hot temperature.
The air flow path is as given herein below →

Blower 202 — Evaporator 204 -
Cold Air Path - Evaporator exit space 218 —
→ Cold air passage 222 — Mixing
Space 212 Mixing space 212 -distribution channel
Blower 202 — Evaporator 204 --

- Evaporator exit space 218 — 208
Warm Air Path Heating chamber 216 — Heater
→ Core 206 — heater top space 232
— Side Pocket (228A) & (228B)
— Mixing Space 212
Figure 8 illustrates a perspective view of the single flap actuation system for a HVAC system temperature regulation of the present disclosure. Arrows "D" shown in Figure 8 illustrates flow of air from the side passage of the flap, when the flap is open condition.
The flap actuation is controlled manually with kinematic linkages or with an actuator motor. The intermediate flap position is based on the temperature required at that particular position of the temperature control knob.
This type of construction for the temperature regulation with a single flap results in effective space utilization in the distribution housing. The flap spoiler

214 and the heater 206 are placed in a way such that it does not allow the condensed water from the evaporator (while dehumidification) to come in contact with the heater core. In most HVAC units known in the art, the heater 206 is completely isolated with the use of two flaps, while in the present disclosure this is achieved with just one flap with an extended spoiler for diverting the flow of air. This elimination of a second flap also results in reduced cost of the unit and more simplicity of working. With this type of construction the heater can be placed close to the evaporator due to which a more compact utilization of space is achieved for the same performance of the unit.
TECHNICAL ADVANCEMENTS AND ECONOMICAL
SIGNIFICANCE
The single flap actuation system for HVAC temperature regulation of the present disclosure is adapted to provide mixing of cold / ambient air in an effective way. Also, the single flap actuation system for HVAC temperature regulation of the present disclosure is adapted to control the mixing of cold air from an evaporator and hot air from a heater in a limited space available in a cost effective way. Further, the single flap actuation system for HVAC temperature regulation of the present disclosure is adapted to provide improved space utilization for mixing of cold / ambient air. Furthermore, the single flap actuation system for HVAC temperature regulation of the present disclosure is simple in construction.
The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions

and quantities than those given herein, fall within the scope of the disclosure, unless there is a statement in the specification to the contrary.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

WE CLAIM:
1. An HVAC system comprising an air blower and a heater disposed
operatively before and after an evaporator respectively,
said system characterized in that:
• the heater is disposed in a position inclined to the horizontal plane;
• a flap is disposed operatively between the evaporator and the heater; a portion of said flap defining a spoiler to selectively control mixing of air from the heater and the evaporator; and
• actuator means is provided which is adapted to co-operate with said flap to selectively move said flap between a closed position, an intermediate position and an open position, said closed position defines a cold air flow from the evaporator to a distribution channel, said open position defines a hot air flow from the heater to a distribution channel and said intermediate position defines a warm air flow wherein a mixture of cold air from the evaporator and hot air from the heater are mixed to attain a pre-determined temperature.
2. The HVAC system as claimed in claim 1, wherein said actuator means co
operates with a temperature sensor.

3. The HVAC system as claimed in claim 1, wherein said actuator means is controlled by at least one of a manual and automated means or a combination thereof.