DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
ELECTRIC AC/HVAC SYSTEM OPERATION DURABILITY ENHANCEMENT BY IMPROVING HEAT-SINK HEAT REJECTION

Applicant:
Tata Motors Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400001,
Maharashtra, India

The following specification particularly describes the invention and the manner in which it is to be performed.
CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
[001] The present application claims priority from Indian Patent application no. (201921011553) filed on 25th March, 2019.

FIELD OF THE INVENTION

[002] The present invention generally relates to vehicles. More particularly, the present invention relates to air conditioning (AC) / Heating, ventilation, and air conditioning (HVAC) system.

BACKGROUND OF THE INVENTION

[003] An electric AC/ HVAC unit contains both mechanical components like the like compressor, condenser, evaporator, blower fans, condenser fans, thermostatic expansion valves and electrical components like the motor driving the electric compressor, blower fans motors and condenser fans motors to name a few. Out of the above-mentioned electric components, typically the motor that operates compressor runs on high voltage (HV - typically 380V or higher) and the motors that operate blower motors and condenser fan motors generally operate on low voltage (LV- typically ~24V). The electric and electronic components in the circuit generate a considerable amount of heat while the electric AC unit is in operation. In order to facilitate rejection of this generated heat into the ambient, heat sinks are provided in the AC/HVAC unit. Heat sinks are typically passive heat exchangers that rely on the airflow over them to convectively or such means of heat transfer to reject heat to the ambient. Typically there are two or more than two heat sinks, one or more heat sinks for HV components and one or more heat sinks for LV components. Insufficient heat rejection from these heat sinks will lead to rise in temperature of heat sinks which in turn will lead to shutting OFF of the AC system.

[004] However, there are factors which may result in inadequate heat rejection from heat sinks as follows
• Improper fitment of the AC unit cover: The AC unit cover is designed with respect to the location of cut-outs for air entry, the placement of heat sinks and condenser or other fans in such a way that the heat sinks lie in the path of the forced air draft. Since the air, like any other fluid, follows the path of least resistance, improper placement of AC unit cover may result in the air bypassing the heat sinks, which in turn will lead to rise in heat sink temperature and shutting OFF of AC system
• In adequate air flow over the heat sinks: For a given AC system, depending on the size the cut-outs for air entry (ies)/exit(s) and the design of the heat sinks, the amount of heat that can be rejected by the heat sinks to the ambient is limited as per the inherent design constraints. Moreover, conventionally irrespective of the actual temperatures of the heat sinks, same amount of air flows over both HV & LV heat sinks, which also results in inadequate heat rejection from either HV or LV heat sink or both and shutting OFF of the AC system.

[005] Thus in a conventional electric AC/HVAC unit, the condenser fan needs to be operated in high speed, as the heat sink temperature rises, in order to facilitate heat rejection from heat sink. Even after this, in severe ambient conditions, the electric AC/HVAC system stops when heat sink temperature crosses the threshold value.

OBJECTS OF THE DISCLOSURE

[006] One object of the present disclosure is to provide an electric AC/HVAC system that resolves the abovementioned problem of inadequate heat rejection and consequent shutting OFF of the electric AC/HVAC system by improving the heat rejection through the heat-sinks efficiently and thus enhancing the operation durability of the electric AC/HVAC system.

[007] Another object of the present disclosure is to provide an electric HVAC system that is easy to operate.

SUMMARY OF INVENTION

[008] According to the present disclosure an enhancement of an Electric AC/HVAC system operation by optimizing the heat rejection of heat-sink is disclosed. Enhancement of an Electric AC/HVAC system operation by optimizing the heat rejection of heat-sink comprising an electric AC/HVAC unit cover configured with at least one cutout [6] for air entry to pass over the heat sink (4, 5) to facilitate heat rejection. A baffle (12) is configured to be placed inside said electric AC/HVAC unit cover and in the path of ambient air to selectively direct the air over the predetermined heat-sinks to facilitate efficient heat rejection. A flap assembly (13.1, 13.2) to selectively direct the cold air to be bled towards the predetermined heat sink to facilitate efficient heat rejection. At lease one condenser fan (3) , in case of air cooled evaporator, for providing the air draft inside an electric AC/HVAC unit cover, one compressor unit (8), at least one evaporator unit (9.1, 9.2) and at least one blower unit (10.1, 10.2) are configured for providing the cold air inside the vehicle. An electric AC/HVAC unit controller integrated inverter + DC/DC converter [2]. At least one roof air ducts (7.1, 7.2) configured to deliver conditioned air to the cabin and at least one contact sensor (11.1, 11.2, 11.3, 11.4) mounted strategically on the predetermined location of an electric AC/HVAC unit cover mounting points to ensure its fitment in prerequisite or intended position to facilitate the air draft over the heat sinks.

[009] The electric AC/HVAC unit controller/ integrated inverter + DC/DC converter [2] is configured to be communicatively connected with the vehicle ECU. The enhancement of an electric AC/HVAC system (1) is configured to optimize the heat rejection without increasing the overall airflow. The system is configured to facilitate adequate heat rejection from heat sink (4, 5) and avoiding intermittently shutting OFF of the electric AC/HVAC system and enhancing the operation durability of the electric AC/HVAC system. The baffle (12) is placed strategically in the path of air configured to direct the air over the predetermined heat-sinks (4,5) for enhanced heat rejection and without increasing the overall airflow. The condenser fan speed is configured to be optionally increased to further reduce the temperature of the heat sink. The contact sensors are configured to be placed strategically on the electric AC/HVAC unit cover mounting points to facilitate and real time monitoring of proper fitment of electric AC/HVAC unit cover for assuring the optimum air draft overheat sinks. The heat sinks (4, 5) are configured with the High voltage (HV) heat sink (4) and Low voltage (LV) heat sink (5) for facilitating heat rejection through them. The baffle (12) is configured to be operated automatically through ECU to divert air delivery with calibrate-able bias towards the heated heat sink that demands higher heat rejection. The roof ducts are configured to divert a fraction of the cold air from the roof ducts to the concerned heat sink to further facilitate heat rejection and enhance AC/HVAC system operation durability.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

[0010] The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

[0011] FIG. 1 illustrates a schematic representation of an Electric Roof AC/HVAC Unit-Normal Operation;

[0012] FIG. 2 illustrates a schematic representation of an Electric Roof AC/HVAC Unit Operation, in accordance with one embodiment of the present invention;

[0013] FIG. 3 illustrates a schematic representation of Air directivity control through baffle, in accordance with one embodiment of the present invention;

[0014] FIG. 4 illustrates a schematic representation of Cold air bleed through flap(s), in accordance with an embodiment of the present invention.

[0015] FIG. 5 illustrates a schematic representation of Contact sensor to guard against improper AC/HVAC unit cover fitment, in accordance with yet another embodiment of the present invention.

[0016] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the system illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION
[0017] The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

[0018] The objective of the invention is to resolve the abovementioned problem of inadequate heat rejection and consequent shutting OFF of the electric AC/HVAC system by improving the heat rejection through the heat-sinks efficiently and thus enhancing the operation durability of the electric AC/HVAC system. The same is being achieved majorly with the help of the following components
• A baffle placed strategically in the path of air to direct the air over the heat-sinks which demands more heat rejection and thus improve the heat rejection without having to increase the overall airflow. Thus avoiding the need to increase condenser fan speed initially. The condenser fan speed can be appropriately increased subsequently if the temperature of the concerned heat sink rise further.
• A flap arrangement to allow for cold air to be bled towards the heat sink that demands more heat rejection.
• A arrangement of contact sensors placed strategically on the electric AC/HVAC unit cover so as to ensure its fitment as per design intent and thus to ensure that the heat sinks are not bypassed by the air draft.

[0019] Figure 1: Shows the regular operation of the typical existing electric AC/HVAC unit. The table describes the numbers that denote the components shown the accompanying images. It shows how the air is typically sucked in through the cutout [6] with the help of draft created by typically the condenser fan(s) [3]. As the air is sucked in it passes over the HV [4] heat sink and LV [5] heat sink facilitating heat rejection through them. The components described are communicatively connected the electric AC/HVAC unit controller/ integrated inverter + DC/DC converter [2] which in turn can be communicatively connected with the vehicle ECU (not shown in images).

[0020] Figure 2: Shows the operation of the proposed electric AC/HVAC unit. The table describes the numbers that denote the additional components in the proposed electric AC/HVAC unit which are shown in the accompanying images. The additional components mentioned are also communicatively connected the electric AC/HVAC unit controller/ integrated inverter + DC/DC converter [2] which in turn can be communicatively connected with the vehicle ECU (not shown in images).

[0021] Figure 3: Shows the air directivity control through the baffle in the proposed electric AC/HVAC unit operation. As per the demand from the heat sink (whichever heat sink has higher temperature and thus demands more heat rejection), the strategically placed baffle can be operated automatically so as to facilitate more air delivery towards the heat sink that demands more heat rejection.

[0022] Figure 4: Shows the cold air bled from the AC/HVAC ducts with the help of proposed flap arrangement. In case the heat sink temperature rises further a fraction of the cold air from the roof ducts can be diverted to the concerned heat sink to further facilitate heat rejection and thus enhance AC/HVAC system operation durability.

[0023] Figure 5.1: Shows the design intended operation of the electric AC/HVAC unit in which the cover design, cut-out location and heat sink location are optimized to ensure heat-sinks are kept in path of air draft.

[0024] Figure 5.2: Shows a case where the electric AC/HVAC unit cover was either not placed properly or some part of it has come undone due to jerks or any other reason. Since the air follows the path of least resistance, if the electric AC/HVAC unit is not closed properly, the air may not pass over the heat sink, leading to inadequate heat rejection and thus consequently shutting OFF of the AC/HVAC system.

[0025] Figure 5.3: Shows strategically placed contact sensors to ensure that the roof unit cover is properly closed. Placement of contact sensors at the mounting points of AC/HVAC unit will ensure that the feedback is provided whether the AC/HVAC unit is in place and its cover is secured properly or not (so as to ensure adequate air flow over heat sink and consequent heat rejection from the same).

[0026] According to the present disclosure an enhancement of an Electric AC/HVAC system operation by optimizing the heat rejection of heat-sink is disclosed. enhancement of an Electric AC/HVAC system operation by optimizing the heat rejection of heat-sink comprising an electric AC/HVAC unit cover configured with at least one cutout [6] for air entry to pass over the heat sink (4, 5) to facilitate heat rejection. A baffle (12) is configured to be placed inside said electric AC/HVAC unit cover and in the path of ambient air to selectively direct the air over the predetermined heat-sinks to facilitate efficient heat rejection. A flap assembly (13.1, 13.2) to selectively direct the cold air to be bled towards the predetermined heat sink to facilitate efficient heat rejection. A condenser fan (3) for providing the air draft inside an electric AC/HVAC unit cover, one compressor unit (8), at least one evaporator unit (9.1, 9.2) and at least one blower unit (10.1, 10.2) are configured for providing the cold air inside the vehicle. An electric AC/HVAC unit controller integrated inverter + DC/DC converter [2]. At least one roof air ducts (7.1, 7.2) configured to deliver cool air to the cabin and at least one contact sensor (11.1, 11.2, 11.3, 11.4) mounted strategically on the predetermined location of an electric AC/HVAC unit cover mounting points to ensure its fitment in prerequisite or intended position to facilitate the air draft over the heat sinks.
[0027] The electric AC/HVAC unit controller/ integrated inverter + DC/DC converter [2] is configured to be communicatively connected with the vehicle ECU. The enhancement of an electric AC/HVAC system (1) is configured to optimize the heat rejection without increasing the overall airflow. The system is configured to facilitate adequate heat rejection from heat sink (4, 5) and avoiding intermittently shutting OFF of the electric AC/HVAC system and enhancing the operation durability of the electric AC/HVAC system. The baffle (12) is placed strategically in the path of air configured to direct the air over the predetermined heat-sinks (4,5) for enhanced heat rejection and without increasing the overall airflow. The condenser fan speed is configured to be optionally increased to further reduce the temperature of the heat sink. The contact sensors are configured to be placed strategically on the electric AC/HVAC unit cover mounting points to facilitate and real time monitoring of proper fitment of electric AC/HVAC unit cover for assuring the optimum air draft overheat sinks. The heat sinks (4, 5) are configured with the High voltage (HV) heat sink (4) and Low voltage (LV) heat sink (5) for facilitating heat rejection through them. The baffle (12) is configured to be operated automatically through ECU to divert air delivery towards the heated heat sink for more heat rejection. The roof ducts are configured to divert a fraction of the cold air from the roof ducts to the concerned heat sink to further facilitate heat rejection and enhance AC/HVAC system operation durability.

Equivalents

[0028] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

[0029] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

[0030] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
,CLAIMS:

1. An Electric AC/HVAC system operation by optimizing the heat rejection of heat-sink comprising of
an electric AC/HVAC unit cover configured with at least one cutout [6] for air entry to pass over the heat sink (4, 5) to facilitate heat rejection;
a baffle (12) configured to be placed inside said electric AC/HVAC unit cover and in the path of ambient air to selectively direct the air over the predetermined heat-sinks to facilitate efficient heat rejection;
at least one flap assembly (13.1, 13.2) to selectively direct the cold air to be bled towards the predetermined heat sink to facilitate efficient heat rejection;
at least one condenser fan (3), in case of air cooled condensers; or a fan otherwise, for providing the air draft inside an electric AC/HVAC unit cover;
at least one compressor unit (8), at least one evaporator unit (9.1, 9.2) and at least one blower unit (10.1, 10.2) for providing the cold air inside the vehicle;
at least one electric AC/HVAC unit controller with or without integrated inverter + DC/DC converter [2];
at least one roof air ducts (7.1, 7.2) configured to deliver cool air to the cabin; and
at least one contact sensor (11.1, 11.2, 11.3, 11.4) mounted strategically on the predetermined location of an electric AC/HVAC unit cover mounting points to ensure its fitment in prerequisite or intended position to facilitate the air draft over the heat sinks.

2. The electric AC/HVAC system as claimed in claim 1 wherein said electric AC/HVAC unit controller/ integrated inverter + DC/DC converter [2] is configured to be communicatively connected with the vehicle ECU.

3. The electric AC/HVAC system as claimed in claim 1 wherein said enhancement of an electric AC/HVAC system (1) is configured to optimize the heat rejection without preferably increasing the overall airflow.

4. The electric AC/HVAC system as claimed in claim 1 wherein said system is configured to facilitate adequate heat rejection from heat sink (4, 5) and avoiding intermittently shutting OFF of the electric AC/HVAC system and enhancing the operation durability of the electric AC/HVAC system.
5. The electric AC/HVAC system as claimed in claim 1 wherein said baffle (12) is placed strategically in the path of air configured to direct the air over the predetermined heat-sinks (4,5) for enhanced heat rejection and without increasing the overall airflow.

6. The electric AC/HVAC system as claimed in claim 1 wherein said condenser fan speed is configured to be optionally increased to further reduce the temperature of the heat sink.

7. The electric AC/HVAC system as claimed in claim 1 wherein said contact sensors are configured to be placed strategically on the electric AC/HVAC unit cover mounting points to facilitate and real time monitoring of proper fitment of electric AC/HVAC unit cover for assuring the optimum air draft over heat sinks.

8. The electric AC/HVAC system as claimed in claim 1 wherein said heat sinks (4, 5) are configured with the High voltage (HV) heat sink (4) and Low voltage (LV) heat sink (5) for facilitating heat rejection through them.

9. The electric AC/HVAC system as claimed in claim 1 wherein said baffle (12) is configured to be operated automatically through ECU to divert air delivery towards the heated heat sink for more heat rejection.

10. The electric AC/HVAC system as claimed in claim 1 wherein said roof ducts are configured to divert a fraction of the cold air from the roof ducts to the concerned heat sink to further facilitate heat rejection and enhance AC/HVAC system operation durability.