Form 2
THE PATENTS ACT, 1970
(39 OF 1970) COMPLETE
specification
SECTION 10
TITLE
" HEATING/VENTILATION/AIR CONDITIONING (HVAC)
SYSTEM HAVING FOOTFLAP INTEGRATED WITH DUCT
AND BAFFLES FOR USE IN MOTOR VEHICLES"
APPLICANTS
BEHR INDIA LTD.
Elpro Premises Chinchwadgaon
Pune 411 033 Maharashtra, INDIA
The following Specification particularly describes the invention and the manner in which it is to be performed.

The invention relates to a Heating/Ventilation/Air conditioning (HVAC) System with Foot Flap integrated with duct and baffles for use in Motor Vehicles.
The invention relates more particularly to a HVAC system which is a module used in an automobile to take care of conditioning the air supplied to the car cabin. It controls heating, cooling and humidity inside the car cabin. Major components of the HVAC system are: ducts, blower, blower motor, evaporator, heater, condenser, compressor, piping, expansion valve, plastic housings to hold heat exchangers, baffles and flaps. The plastic housings and flaps play an important role in proper distribution of air at different outlets. A high level of comfort is being increasingly demanded by automobile users, creating thereby more challenges for the designers of HVAC systems.
The present invention relates more specifically to a HVAC system for heating and air conditioning of motor vehicles, in which the customer specifications for Air-Flow distribution in different modes of operation of the system and also Thermal Balance in the bi-level modes of operation of the system have been met by using a FOOT FLAP which is structurally integrated with a duct and baffles to form a single unit for controlling the flow of a part of hot air directly into the system. Different modes of air flow in operating the invented HVAC system are: a) Face mode, b) Foot mode, c) Defrost mode, d) Face-Foot mode, e) Defrost-Foot mode. The last two modes i.e. mode d) and mode e) are called bi-level modes. In these two modes air is guided either through, the face duct and the foot duct or through the defrost duct and the foot duct. Achieving customer specifications in these two modes without increasing the cost of production of the HVAC system is a challenging job, as it is necessary to have proper mixing of hot air and cold air inside the

HVAC system and to ensure proper distribution of the mixed hot air and cold air in the car cabin to meet the customer specifications.
The present invention lies mainly in the structural integration of the Foot Flap with a duct and baffles to form a single unit. The foot flap is one of the different flaps used in the HVAC system, and serves the primary functions of controlling the flow of hot air entering into the Foot outlet and also acts as 'duct and baffles' to guide flow of hot air directly into the mixing chamber of the system. In the existing HVAC systems foot flap, duct and baffles are used as three separate components each functioning independently of one another. The customer specifications for distribution of airflow and comfort could not, however, be met by using the foot flap, duct and baffles functioning independently as separate components.
After conducting extensive experiments by modification of the construction of the foot flap, duct and baffles, and their controlling mechanisms, it has been ultimately identified/found that the customer specifications for distribution of air-flow and thermal balance in the car cabin can be met by simply integrating structurally the foot flap with a duct and baffles to form a single composite unit, without using any specially designed and constructed additional components for the purpose, in the existing HVAC system. The structural integration of the foot flap with a duct and baffles has also resulted in saving of manufacturing cost of the integrated unit of foot flap, duct and baffles because a single mould can be used for producing the same, instead of using three separate moulds for producing the said three components separately.

HVAC Systems and devices for motor vehicles using different means of controlling the proportion of Hot and Cold air supplied into the mixing chambers for ventilation and defrost outlet ducts are known in the prior art.
Patent No. FR2765526 discloses a heating and/or air conditioning system, particularly for motor vehicles, in which fresh air from outside is fed into a mixing chamber for Hot and Cold air, partly directly and partly through a heating chamber, in proportion which is controlled by a specially designed and constructed mixing flap.
Patent No. FR2788019 discloses a device for heating and/or air conditioning the passenger compartment of a motor vehicle, in which the proportion of Hot and Cold air fed into a mixing chamber is varied by using two specially designed and constructed drum-shaped flaps which are pivoted co-axially and provided each with at least one integrated channel for allowing passage of Hot and Cold air into the mixing chamber of the device.
Patent application No. WO 2005 000 610 discloses a ventilation device, especially for a heating or air conditioning system of a motor vehicle, in which two specially designed flaps are provided in a housing for controlling the flow of ventilation air into different areas of the passenger compartment of a motor vehicle through a number of outlet ducts.
The above mentioned prior arts are not relevant to the present invention which relates to a HVAC system for use in motor vehicles, containing a Foot Flap which is structurally integrated with a duct and baffles for controlling and guiding the flow of a part of the hot air supplied directly into the main mixing chamber of the systems and is of relatively simple design and hence of low-cost construction, and found to be suitable for meeting the customer specifications of Air-Flow distribution in different modes of operation of the system, and thermal balancing in Bi-Level mode of operations of the system.

The object of the present invention is to provide a HVAC system for use in motor vehicles, which meets the customer specifications for air flow distribution and thermal balancing, and is of relatively simple design and hence low cost construction.
The HVAC system for use in motor vehicles, according to the present invention, comprises mainly a cold air supply zone, a hot air supply zone, primary mixing chamber for cold and hot air, a main mixing chamber for cold and hot air, a defrost outlet, a foot outlet and a foot flap which is structurally integrated with a duct and baffles for controlling the flow of a part of hot air directly into the main mixing chamber. The duct and baffles integrated with the foot flap prevent a part of the hot air supplied there through from being mixed with the cold air supplied through the primary mixing chamber, and allow the said part of the hot air to enter directly into the main mixing chamber. The integrated unit comprising the foot flap, a duct and baffles is mounted rotatably in the primary mixing chamber. When the flap of this integrated unit is close, it prevents hot air from entering into the foot outlet. As the flap starts opening, it allows air to flow from the primary mixing chamber into the foot outlet and at the same time the duct and baffles of the integrated unit guide a part of the hot air to flow from the hot air zone directly into the main mixing chamber of the system. In this way the integrated unit permits achieving the Air Flow Distribution and Thermal Balance to meet customer specifications by operating the HVAC system in different modes as stated hereinbefore.
Thus the present invention provides a heating/ventilation/air
conditioning (HVAC) system having foot flap integrated with duct and baffles
for use in motor vehicles comprising a cold air supply zone, an evaporator, a
heater, a hot air supply zone, a primary mixing chamber, a main mixing
chamber, a defrost outlet, a foot outlet and a foot flap, characterised in that
the foot flap is structurally integrated with a duct and baffles, and rotatably
mounted for controlling the flow of a part of the hot air supply to the main
mixing chamber without being mixed with cold air in the primary mixing
chamber.
The invention is described in detail, without restricting the scope of the invention in any manner, with reference to the accompanying drawings in which-
Figure-1 illustrates the disposition of different zones, chambers, outlet ducts and foot flap integrated with a duct and baffles and also air-flow directions from cold air zone and hot air zone into the primary and main mixing chambers, and defrost and foot outlets of the invented HVAC system;
Figure- 2 illustrates the Foot Flap integrated with a duct and baffles, pivotably mounted in different positions in the HVAC system;
Figure- 3 illustrates the flow of Hot air and Cold air first into the primary mixing chamber and then into the main mixing chamber, and the flow of a part of the hot air through the foot flap integrated with a duct and baffles directly into the main mixing chamber as well as into the foot outlet;
Figures- 4,5,6 and 7 present test results obtained in different modes of operation of the invented HVAC system.
Referring to Fig. 1, the invented HVAC system comprises a cold air supply zone (CZ), a hot air supply zone (hZ), a primary mixing chamber (PMC), a main mixing chamber (MMC), a defrost outlet (DO), a foot outlet (FO), a heater (HT), an evaporator (EV), a foot flag (FF), integrated with a duct (DT) and baffles (BF) and rotatably mounted in pivots (PV).
Cold air from zone (CZ) is allowed to flow via evaporator (EV) and chamber (PMC) into chamber (MMC). Hot air produced in zone (HZ) by heater (HT) is also allowed to flow mainly via chamber (PMC) into chamber (MMC), and only partly, as collected by baffles (BF), via duct (DT) directly into chamber (MMC) or into defrost outlet (DO) or into foot outlet (FO) depending on the degree of opening of foot flap (FF), through rotation in pivots (PV) according to different modes of operation of the system.

Referring to Fig. 2A, the foot flap (FF) is depicted before the integration thereof with a duct and baffles.
Referring to Figs. 2(B) to 2(D), foot flap (FF), which is structurally integrated with duct (DT) along a line of attachment (IL) and also with baffles (BF), is shown rotatably mounted in pivots (PV) for performing the following functions:
1. To control the flow of a part of hot air into foot outlet (FO).
2. To control, the distribution of a part of hot air into the HVAC system when it operates in the bi-level mode.
3. To collect a part of the hot air flowing from zone,(HZ) with baffles (BF) and direct it into main mixing chamber (MMC) via duct (DT), without being mixed with cold air in the primary mixing chamber (PMC), and to achieve thereby the desired thermal balance in different modes of operation of the HVAC system.
4. To supply hot air directly into defrost outlet (DO) when the HVAC system is operated in the Defrost mode.
Duct (DT) is made of drum shape, substantially square cross section and bent configuration in the vertical plane.
Foot flap (FF) is made of substantially rectangular shape and bent configuration along the length thereof so that the curvature thereof is the same as that of the corner edge of the duct which is attached to the longitudinal edge of the foot flap.
Baffles (BF) are each made of sheets of substantially semi-circular shape, the straight edge of which is joined to the inner surface of a side of the duct, so as to block about 30 to 40 % of the duct operature.
The integrated unit of foot flap (FF), duct (DT) and baffles (BF), designed to be a single unit, is made preferably of plastics which can be moulded in a single mould.

Referring to Fig. 3, the flow of cold air and hot air respectively from, zones (CZ) and (HZ) is allowed first into primary mixing chamber (PMC) and then the flow of a part of the hot air from zone (HZ) takes place through the foot flap (FF) integrated with duct (DT) and baffles (BF) directly into main mixing chamber (MMC).
Referring to Figs. 4,5,6 and 7, the test results of thermal balance obtained by using the invented HVAC system in motor vehicles in the bi-level mode of operation thereof i.e. Foot-Defrost mode and Foot-Ventilation mode, show that difference in temperature of air flow at the foot and Defrost levels (Figs 4 and 6) varies from -1°C to +6°C in the area covering upto 50% of mixing flap opening position, and from +5°C to + 11°C in the remaining area; and at the Foot and Ventilation levels (Figs 5 and 7) varies from -2.5 °C to +15°C in the area covering upto 30% of mixing flap opening, from +5°C + 15°C in the area covering from 30% to 70% opening of mixing flap and from -2.5° C to +15°C in the remaining area of mixing flap opening.
The test results shown in Figs. 4, 5, 6 and 7 meet customer specifications of Thermal balancing of HVAC system for motor vehicles.
The test results obtained on Air flow distribution in different modes by using the invented HVAC system for motor vehicles are presented in Table-1, from which it is noted that the percentage of total air flow rate in Kg/h in Foot, Foot-Defrost and Foot-ventilation modes of operation closely meet the values of RFQ i.e. Request for Quotation according to costomer specifications.
The advantages attained by using the invented HVAC system containing the Integrated Foot Flap are -
1) Requirement of Air flow distribution in different modes of operation of the HVAC system and Temperature stratification in bi-level modes of its operation have been met by using the Foot Flap integrated with a duct and baffles and functioning as a single unit.
78/

2) The integrated unit of Foot flap, duct and baffles is of relatively simple design and low-cost construction from manufacturing point of view, does not require incorporation of any specially designed and relatively expensive components in the system to meet the customer specifications for air-flow distribution and thermal balance.
2) A part of hot air can be guided directly into the defrost outlet to attain the desired temperature in the defrost mode of operation of the system.
3) The integrated unit of foot flap, duct and baffles can be produced using a single mould with the resultant saving in cost required for moulding the three components i.e.foot flap, duct and baffles in three separate moulds.

We claim :-
1. A heating/ventilation/air conditioning (HVAC) system having foot flap integrated with duct and baffles for use in motor vehicles comprising a cold air supply zone (CZ), an evaporator (EV), a heater (HT), a hot air supply zone (HZ),a primary mixing chamber (PMC),a main mixing chamber (MMC), a defrost outlet (DO), a foot outlet (FO), and a foot flap, characterised in that the foot flap is structurally integrated with a duct (DT) and baffles (BF) and is mounted rotatably for controlling the flow of a part of the hot air supplied to the main mixing chamber without being mixed with air in the primary mixing chamber.
2. The HVAC system as claimed in claim 1 wherein the foot flap is mounted rotatably in pivots (PV).
3. The HVAC system as claimed in claim 1 or 2, wherein duct (DT) for supplying a part of the hot air directly into main mixing chamber (MMC) is structurally attached to foot flat (FF) along the line (IL),and also to baffles (BF) used for collecting a part of the hot air and then guiding the same into duct (DT).
4. The HVAC system as claimed in any preceding claim, wherein the foot flap (FF),integrally attached to duct DT) and baffles (BF) is adapted to meet the customer specifications for air flow distribution and thermal balance.
5. A heating/ventilation/air conditioning (HVAC) system having foot flap integrated with duct and baffles for use in motor vehicles, substantially as herein described and illustrated in the accompanying drawings.
Dated this 7mday of August 2006.
CE>, L. E>ANr£p-J££)
er£ DePENNING & DePENNING Agent for the Applicants

ABSTRACT
Title: Heating/ventilation/air conditioning system (HVAC) having foot flap integrated with duct and baffles for use in motor vehicles"
A HVAC system for motor vehicles, capable of meeting customer specifications for air flow distribution and thermal balance and comprising a cold air supply zone (CZ), a hot air supply zone (HZ), a primary mixing chamber (PMC), main mixing chamber (MMC) for mixing hot and cold air, and an integrated Foot Flap (FF), duct (DT) and baffles (BF) for controlling the air entering into foot outlet (FO), when the HVAC is in Foot mode and also the air entering into main mixing chamber (MMC) when the HVAC is in any other mode than Foot mode. The foot flap integrated with a duct and baffles functions as a single unit and allows a portion of Hot air coming from hot zone (HZ) to enter directly into main mixing chamber (MMC) without getting in touch with cold air coming from cold zone (CZ). Baffles (BF) collect a portion of hot air from hot zone (HZ) and guide it into duct (DT).
Reference: Figures 1 to 7 of the accompanying drawings.