Claims:We claim:

1. An air-conditioning system (100) for cooling a passenger cabin of a vehicle, the system (100) comprising:
a primary loop (101) carrying a refrigerant, the primary loop (101) comprising:
a compressor (102) selectively coupled to an engine (103) of the vehicle;
a condenser (104);
a receiver-dryer (105); and
a chiller (106) housing a thermal expansion valve (107);
a secondary loop (108) carrying a coolant, the secondary loop (108) comprising:
a reservoir (109) configured to store the coolant;
a coolant pump (110); and
a cooler (111), wherein air blows across the cooler (111) to exchange heat with the coolant,
wherein, the chiller (106) acts as a heat exchanger for exchanging heat between the refrigerant of the primary loop (101) and the coolant of the secondary loop (108); and
an Electronic Control Unit (ECU) (112) configured to selectively disengage the compressor (102) from the engine (103) and engage the compressor (102) with a regenerative energy source (113) during deceleration of the vehicle.

2. The system (100) as claimed in claim 1, wherein the secondary loop (108) includes a by-pass valve (114) to selectively allow the coolant through the reservoir (109).

3. The system (100) as claimed in claim 1, wherein the refrigerant is at least one of R134a, R152a and HFO1234yf.

4. The system (100) as claimed in claim 1, wherein the coolant is ethylene glycol and water based solution.

5. The system (100) as claimed in claim 1, wherein the reservoir (109) includes a temperature sensor (115) to determine the temperature of the coolant in the reservoir (109).

6. The system (100) as claimed in claim 5, wherein the ECU (112) calculates threshold values of temperature of the coolant in the reservoir (109) for different operating modes of the vehicle.

7. The system (100) as claimed in claim 6, wherein the threshold values of the temperature of the coolant in the reservoir (109) is calculated based on parameters including ambient temperature conditions.

8. The system (100) as claimed in claim 6, wherein the operating modes of the vehicle includes idle mode, acceleration mode, deceleration mode and engine stop or start request mode.

9. The system (100) as claimed in claim 5, wherein the ECU (112) is configured to selectively disengage the compressor (102) with the engine (103) of the vehicle and activate the coolant pump (110) based on parameters including the operating mode of the vehicle, temperature of the coolant in the reservoir (109), state of the engine (103) and cooling demand from an user of the vehicle.

10. The system (100) as claimed in claim 9, wherein when the vehicle is in idle mode, temperature of the coolant in the reservoir (109) is less than lower limit of the threshold value of the temperature of coolant in the reservoir in the idle mode, state of the engine (103) is OFF and there is cooling demand from the user, the ECU (112) disengages the compressor (102) from the engine (103) and activates the coolant pump (110) to cool the passenger cabin.

11. The system (100) as claimed in claim 9, wherein when the vehicle is in acceleration mode, temperature of the coolant in the reservoir (109) is less than lower limit of the threshold value of temperature of the coolant in the reservoir (109) in the acceleration mode, state of the engine (103) is ON and there is cooling demand from the user, the ECU (112) disengages the compressor (102) from the engine (103) and activates the coolant pump (110) to cool the passenger cabin.

12. The system (100) as claimed in claim 9, wherein when the vehicle is in deceleration mode, temperature of the coolant in the reservoir (109) is less than lower limit of the threshold value of temperature of the coolant in the deceleration mode, state of the engine (103) is ON and there is cooling demand from the user, the ECU (112) disengages the compressor (102) from the engine (103) and activates the coolant pump (110) to cool the passenger cabin.

13. The system (100) as claimed in claim 9, wherein when the vehicle is in engine stop request mode, temperature of the coolant in the reservoir (109) is less than lower limit of the threshold value of the temperature of coolant in the reservoir in the idle mode, state of the engine (103) is OFF and there is cooling demand from the user, the ECU (112) disengages the compressor (102) from the engine (103) and activates the coolant pump (110) to cool the passenger cabin.

14. The system (100) as claimed in claim 1, wherein the ECU (112) is configured to selectively disengage the compressor (102) from the engine (103) to drive the compressor (102) through the regenerative energy source (113) during the deceleration of the vehicle when there is no cooling demand from the user.

15. A method of cooling a passenger cabin of a vehicle through a dual loop air-conditioning system (100) including:
a primary loop (101) carrying a refrigerant, the primary loop (101) comprising:
a compressor (102) selectively coupled to an engine (103) of the vehicle;
a condenser (104);
a receiver-dryer (105); and
a chiller (106) housing a thermal expansion valve (107);
a secondary loop (108) carrying a coolant, the secondary loop (108) comprising:
a reservoir (109) configured to store the coolant;
a coolant pump (110); and
a cooler (111), wherein air blows across the cooler (111) to exchange heat with the coolant,
wherein, the chiller (106) acts as a heat exchanger for exchanging heat between the refrigerant of the primary loop (101) and the coolant of the secondary loop (108), the method comprising:
disengaging, by an Electronic Control Unit (ECU) (112) of the vehicle, the compressor (102) from the engine (103) and engaging the compressor (102) with a regenerative energy source (113) during deceleration of the vehicle; and
activating, by the ECU (112), the coolant pump (110) to cool the passenger cabin of the vehicle.

16. The method as claimed in claim 15 comprising, determining by a temperature sensor (115) housed in a reservoir (109), temperature of the coolant in the reservoir (109).
17. The method as claimed in claim 16 comprising, calculating by the ECU (112) threshold values of temperature of the coolant in the reservoir (109) for different operating modes of the vehicle.

18. The method as claimed in claim 17, wherein the threshold values of the temperature of the coolant in the reservoir is calculated based on parameters including ambient temperature conditions.

19. The method as claimed in claim 17, wherein the operating modes of the vehicle includes idle mode, acceleration mode and deceleration mode.

20. The method as claimed in claim 16, wherein the ECU (112) is configured to selectively disengage the compressor (102) with the engine (103) of the vehicle and activate the coolant pump (110) based on parameters including the operating mode of the vehicle, temperature of the coolant in the reservoir (109), state of the engine (103) and cooling demand from an user of the vehicle.

21. The method as claimed in claim 20, wherein when the vehicle is in idle mode, temperature of the coolant in the reservoir (109) is less than lower limit of the threshold value of the temperature of the coolant in the reservoir (109) in the idle mode, state of the engine (103) is OFF and there is cooling demand from the user, the ECU (112) disengages the compressor (102) from the engine (103) and activates the coolant pump (110) to cool the passenger cabin.

22. The method as claimed in claim 20, wherein when the vehicle is in acceleration mode, temperature of the coolant in the reservoir (109) is less than lower limit of the threshold value of the temperature of the coolant in the reservoir (109) in the acceleration mode, state of the engine (103) is ON and there is cooling demand from the user, the ECU (112) disengages the compressor (102) from the engine (103) and activates the coolant pump (110) to cool the passenger cabin.

23. The method as claimed in claim 20, wherein when the vehicle is in deceleration mode, temperature of the coolant in the reservoir (109) is less than lower limit of the threshold value of the temperature of the coolant in the reservoir (109) in the deceleration mode, state of the engine (103) is ON and there is cooling demand from the user, the ECU (112) disengages the compressor (102) from the engine (103) and activates the coolant pump (110) to cool the passenger cabin.

24. The system (100) as claimed in claim 20, wherein when the vehicle is in engine stop mode, temperature of the coolant in the reservoir (109) is less than lower limit of the threshold value of the temperature of coolant in the reservoir in the idle mode, state of the engine (103) is OFF and there is cooling demand from the user, the ECU (112) disengages the compressor (102) from the engine (103) and activates the coolant pump (110) to cool the passenger cabin.

25. The method as claimed in claim 16, wherein the ECU (112) is configured to selectively disengage the compressor (102) from the engine (103) to drive the compressor (102) through regenerative energy source (113) during deceleration of the vehicle when there is no cooling demand from the user.

26. A vehicle comprising an air-conditioning system (100) for cooling a passenger cabin as claimed in claim 1. , Description:
TECHNICAL FIELD

The present disclosure generally relates to the field of automobiles. Particularly, but not exclusively, the present disclosure relates to air-conditioning system of a vehicle. Further embodiments of the present disclosure disclose a dual loop air-conditioning system that uses energy from regenerative braking to cool the passenger cabin of the vehicle.

BACKGROUND

For several years now, air conditioning systems have been used in automobiles and other motor vehicles during hot and cold weather conditions to improve the comfort for driver and other occupants of the motor vehicles. Traditional air conditioning systems utilize a refrigerant to cool and/or dehumidify air. The cool air is then dispersed into the passenger compartment in a manner so as to mitigate the temperature in the passenger compartment.

Traditional automotive air conditioning systems draw the power from the engine of the motor vehicle to compress the refrigerant. Generally, an engine fan belt pulley is connected to the engine and to the compressor of the air conditioning system. Conventionally, R134a was used as a refrigerant. However, it was to be replaced, because of its high greenhouse warm potential as per Montreal Protocol. As an alternative, R744, HFO1234yf or R152a refrigerants are used for the air conditioning applications. However, R152a and HFO1234yf are mildly flammable and toxic, thus they cannot be directly in contact with passengers.

For the sake of the health of passengers and for safety reasons, especially in case of any leakage in the air conditioning system, it should be avoided to perform a refrigerant cycle, which is filled with such refrigerants to reach the passenger compartment. Therefore, the air conditioning systems have been developed with dual loop, including a primary loop and a secondary loop. The primary loop is a refrigerant circuit, whose operation is performed completely in the engine compartment and the secondary loop is coupled via heat exchanger with the primary loop and is used to cool the cabin air.

Such "secondary loop" systems have already been proposed in previous publications. Secondary loop systems have significant advantages over conventional single loop systems such as - use of reservoir which can act as cold storage, refrigerant circuit isolation in engine bay, lower refrigerant charge, fewer fittings, and shorter refrigerant hoses which reduce refrigerant emissions particularly for multiple cooling point application and reduced air conditioning system noise.

However, these systems are limited to the need of belt driven compressors, which draw power from the engine and additional power consuming components, for example, electric pump for coolant circulation may be necessary. This affects the overall fuel economy of vehicle. Also, the introduction of an additional heat exchange process further reduces the efficiency of the existing system.

The present disclosure is directed to overcome the one or more problems stated above or any other limitations associated with the conventional arts.

SUMMARY OF THE DISCLOSURE

One or more shortcomings of conventional systems are overcome and additional advantages are provided through the system as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed disclosure.

In one non-limiting embodiment of the disclosure an air-conditioning system for cooling a passenger cabin of a vehicle is disclosed. The system includes a primary loop carrying a refrigerant, the primary loop includes a compressor selectively coupled to an engine of the vehicle, a condenser, a receiver-dryer, and a chiller housing a thermal expansion valve. The system further includes a secondary loop carrying a coolant. The secondary loop includes a reservoir configured to store the coolant, a coolant pump, and a cooler, wherein air blows across the cooler to exchange heat with the coolant. The chiller acts as a heat exchanger for exchanging heat between the refrigerant of the primary loop and the coolant of the secondary loop. The system also includes an Electronic Control Unit (ECU) configured to selectively disengage the compressor from the engine and engage the compressor with a regenerative energy source during deceleration of the vehicle.

In an embodiment of the disclosure, the secondary loop includes a by-pass valve to selectively allow the coolant through the reservoir.

In an embodiment of the disclosure, the refrigerant is at least one of R134a, R152a or HFO1234yf.

In an embodiment of the disclosure, the coolant is ethylene glycol and water based solution.

In an embodiment of the disclosure, the reservoir includes a temperature sensor to determine the temperature of the coolant in the reservoir.

In an embodiment of the disclosure, the ECU calculates threshold values of temperature of the coolant in the reservoir for different operating modes of the vehicle. The threshold values of the temperature of the coolant in the reservoir are calculated based on parameters including ambient temperature conditions. The operating modes of the vehicle includes idle mode, acceleration mode, deceleration mode and engine stop or start mode.

In an embodiment of the disclosure, the ECU is configured to selectively disengage the compressor with the engine of the vehicle and activate the coolant pump based on parameters including the operating mode of the vehicle, temperature of the coolant in the reservoir, state of the engine and cooling demand from an user of the vehicle.

In an embodiment of the disclosure, when the vehicle is in idle mode, temperature of the coolant in the reservoir is less than lower limit of the threshold value of the temperature of the coolant in the reservoir in the idle mode, state of the engine is OFF and there is cooling demand from the user, the ECU disengages the compressor from the engine and activates the coolant pump to cool the passenger cabin.

In an embodiment of the disclosure, when the vehicle is in acceleration mode, temperature of the coolant in the reservoir is less than lower limit of the threshold value of temperature of the coolant in the reservoir in the acceleration mode, state of the engine is ON and there is cooling demand from the user, the ECU disengages the compressor from the engine and activates the coolant pump to cool the passenger cabin.

In an embodiment of the disclosure, when the vehicle is in deceleration mode, temperature of the coolant in the reservoir is less than lower limit of the threshold value of temperature of the coolant in the deceleration mode, state of the engine is ON and there is cooling demand from the user, the ECU disengages the compressor from the engine and activates the coolant pump to cool the passenger cabin.
In an embodiment of the disclosure, when the vehicle is in engine stop mode, temperature of the coolant in the reservoir is less than lower limit of the threshold value of the temperature of coolant in the reservoir in the idle mode, state of the engine is OFF and there is cooling demand from the user, the ECU disengages the compressor from the engine and activates the coolant pump to cool the passenger cabin.

In an embodiment of the disclosure, the ECU is configured to selectively disengage the compressor from the engine to drive the compressor through the regenerative energy source during the deceleration of the vehicle when there is no cooling demand from the user.

In another non-limiting embodiment of the disclosure, a method of cooling a passenger cabin of a vehicle through a dual loop air-conditioning system is disclosed. The system includes a primary loop carrying a refrigerant, the primary loop includes a compressor selectively coupled to an engine of the vehicle, a condenser, a receiver-dryer, and a chiller housing a thermal expansion valve. The system further includes a secondary loop carrying a coolant. The secondary loop includes a reservoir configured to store the coolant, a coolant pump, and a cooler, wherein air blows across the cooler to exchange heat with the coolant. The chiller acts as a heat exchanger for exchanging heat between the refrigerant of the primary loop and the coolant of the secondary loop. The method includes disengaging, by an Electronic Control Unit (ECU) of the vehicle, the compressor from the engine and engaging the compressor with a regenerative energy source during deceleration of the vehicle and activating, by the ECU, the coolant pump to cool the passenger cabin of the vehicle.

It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, and 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 drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:

FIG.1 is a schematic representation of a dual loop air-conditioning system for cooling a passenger cabin of a vehicle, in accordance with an embodiment of the present disclosure.

FIG.2 is a graphical representation of temperature of coolant in the reservoir for different operating modes of a vehicle, in accordance with an embodiment of the present disclosure.

FIGs.3-7 illustrates flowcharts of a method for cooling passenger cabin of the vehicle operating under different modes, in accordance with an embodiment of the present disclosure.

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 and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

It is to be noted that a person skilled in the art would be motivated from the present disclosure and would modify various constructions of the air conditioning system, which may vary from one vehicle to vehicle. However, such modifications should be considered to be within the scope of the disclosure. Accordingly, the drawings show only those specific details that are pertinent to understand the embodiments of the present disclosure, so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

The air condition system of the present disclosure may be employed in any kind of vehicle ranging from passenger vehicles to commercial vehicles.
The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, system, assembly that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or device.

Embodiments of the present disclosure disclose a system and a method of cooling a passenger cabin of a vehicle. The present disclosure adopts a dual-loop air-conditioning system consisting of a primary loop and a secondary loop. The primary loop may be a normal vapour absorption refrigeration system consisting of a compressor, condenser, receiver dryer and chiller housing a thermal expansion valve. Further, the secondary loop includes a reservoir to store coolant, a coolant pump and a cooler. The air may be conditioned in the secondary loop before it is let into the passenger cabin. In an embodiment, the secondary loop also includes a by-pass valve, to allow flow of the coolant selectively into the reservoir. The chiller may act as a common element for the primary loop and the secondary loop, wherein heat may be exchanged between refrigerant carried in the primary loop and coolant flowing in the secondary loop.

In an embodiment, the method to improve fuel economy is to store thermal energy in a medium using vehicle waste energy such as by recovering lost kinetic energy during deceleration or during engine fuel cut off. The kinetic energy may be recovered through a regenerative energy source which may be selectively coupled to the compressor of the primary loop. The compressor may utilize this energy to initiate the process of air-conditioning and subsequently cool the coolant. The present disclosure improves the fuel economy of the vehicle, by selectively disengaging the compressor from the engine of the vehicle and activating the coolant pump of the secondary loop to provide cooling.

The system includes an Electronic Control Unit (ECU) of the vehicle, which may be configured to selectively disengage the compressor from the engine activate the coolant pump based on different operating modes of the vehicle. In an embodiment, during deceleration, the compressor may be disengaged from the engine and coupled to regenerative energy source cool the coolant in the reservoir to a predetermined temperature level. Upon termination of deceleration or if the predetermined cooling level is reached, the compressor may be disengaged from the regenerative energy source. When the vehicle is at a stop and the engine is not running, the air flowing across the cooler is continued to be cooled with the coolant stored in the reservoir while the vehicle engine and thus the compressor of the air conditioning system is disengaged from the engine. This provides fuel savings as there is no need to run the engine when the vehicle is at a stop to continue to maintain cool air flowing into the passenger cabin.

The thermal energy stored in reservoir may be used to provide cabin cooling while keeping AC compressor off during peak load conditions (e.g. high acceleration) or part load conditions. Also when the automobile is going downhill with sufficient power and is being decelerated, the compressor may be engaged to the regenerative energy source to recuperate the waste energy and stored as thermal energy in reservoir.

The following paragraphs describe the present disclosure with reference to FIGS. 1 to 7. In the figures, the same element or elements which have similar functions are indicated by the same reference signs. In the figures, the vehicle is not illustrated for the purpose of simplicity.

As shown in FIG.1, the air-conditioning system (100) for cooling a passenger cabin of a vehicle, consists of a primary loop (101) and a secondary loop (108) that share a common heat exchanger, referred to as chiller (106).

The primary loop (101) is a direct expansion refrigeration system which has a compressor (102), a condenser (104), a receiver-dryer (105), a thermal expansion valve (107) and a condenser fan. Refrigerant that may be used in the primary loop (101) may be a phase changing fluid and is usually the standard refrigerant used in automotive vehicles. The refrigerant may be such as but not limited to R134a, R152a or HFO1234yf. The refrigerant flows inside the primary loop (101). In accordance with various embodiments, the primary loop (101) of the air-conditioning system (100) may be accommodated in compartment of the engine (103).

The secondary loop (108) contains the chiller (106), coolant reservoir (109) with temperature sensor (115), a coolant pump (110) and a cooler (111). In an embodiment, the chiller (106) may be a brazed plate heat exchanger. The chiller (106) may also house the thermal expansion valve (107) of the primary loop (101). In an embodiment, the coolant may be an ethylene glycol and water based solution. The system (100) includes an electronic control unit (112) of the vehicle which may be used to manipulate the actuators present in the system based on different operating modes of the vehicle. The ECU (112) may communicate through hardwired signals. In an embodiment, the inputs to the ECU (112) received through hardwired signals may include cooling demand from user, cooler air out temperature, reservoir coolant temperature, chiller out coolant temperature, high side and low side pressure inputs. Further, the ECU (112) may control a by-pass valve (114) to selectively allow flow of the coolant to the reservoir (109). The ECU (112) may also selectively activate the coolant pump (110), disengage the compressor (102) and condenser fan. In an embodiment, parameters such as engine speed, clutch/neutral state, vehicle speed, ignition key state, brake signal, ambient temperature, engine on/off state and engine idle stop/start state may also be received by the ECU (112) through an engine control module and/or transmission control module associated with the ECU (112).

User sends the cooling demand signal to the ECU (112) and subsequently based on refrigerant pressure safe operating limits and after assessing safe operating conditions of engine, sends a compressor clutch engage/disengage signal to the compressor (102). As the compressor (102) starts, the refrigerant circulates in the primary loop (101) that works on the principle of vapour compression refrigeration cycle. To fulfil the user cooling demand, the ECU (112) sends the activation signal to the coolant pump (110) that start circulating the coolant in the secondary loop (108). The refrigerant and coolant heat exchange happens inside the chiller (106), wherein the refrigerant removes heat from the coolant. The coolant after exchanging heat from the refrigerant will flow to the cooler (111) which is present in the passenger cabin of the vehicle. The air blown out from the blower may be circulated over the cooler (111) which reduces the temperature of the air. The cold air is circulated through the passenger cabin via ducts. During high ambient temperature conditions, the ECU (112) may switch on the by-pass valve (114) which eliminates the reservoir (109) from the secondary loop (108) circuit for short periods. This improves the cool down performance of the air conditioning system (100) and quick cooling may be provided to the user.

Referring now to FIGs.3-7 in conjunction with FIG.2, is used to depict the method of operation of the air-conditioning system (100) under different operating modes of the vehicle. Firstly, the ECU (112) is configured to determine threshold limits of temperature of the coolant in the reservoir (109) for compressor (102) cut off and cut in (i.e. compressor disengage and engage respectively) in different operating modes.

FIG.2 shows the temperature limits of the coolant in the reservoir (109), that may be set for different operating modes. The different operating modes may include:

Idle Mode: This mode is activated when the engine idle conditions are detected,
Acceleration Mode: This mode is activated when vehicle acceleration conditions are detected,
Deceleration Mode: This mode is activated when vehicle braking conditions are detected, and
Normal Mode: The default mode of operation, when none of the above conditions are detected.

In an embodiment, the operating mode may also include engine stop or start request.

In an embodiment, the ECU (112) may dynamically select the applicable reservoir threshold limits based on the current operating mode and the absolute value of individual thresholds may be updated based on various external factors such as but not limited to ambient temperature.

As illustrated in flowcharts of FIGs.3-7, the method includes one or more blocks illustrating a method for cleaning the charging unit. The method may be described in the general context of computer executable instructions. Generally, computer executable instructions can include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform functions or implement abstract data types.

The order in which the method is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the spirit and scope of the subject matter described herein. Furthermore, the method can be implemented in any suitable hardware, software, firmware, or combination thereof.

Referring to FIG.3, after updating the threshold limits of temperature of the coolant in the reservoir (109), the current ambient conditions may be checked. If low ambient conditions are detected and there is no cooling demand from user, the compressor (103) and the coolant pump (110) may be switched off as shown at 116. If the user demands cooling (even in low ambient conditions) or ambient condition is not cold, then the ECU (112) will check for current engine state. If the engine state is ON and there is cooling demand from the user, the ECU (112) may look for engine stop request from start/stop logic. The ECU (112) may allow engine stop if the current temperature of the coolant in the reservoir (Tres) is below the allowed lower limit for idle compressor cut off (Tres_idledwn). In such case, the compressor (102) may be kept off and the coolant pump (110) may be switched ON to circulate the coolant in secondary loop (108) as shown at 117. Thus, allowing engine (103) off with cabin cooling maintained.

Further, when the engine (103) is off, in the next updated cycle the flowchart will go to location ‘A’. Referring to FIG.4, during engine off condition, if the ignition key is ON or in accessories mode and there is demand from user for cooling then the temperature of the reservoir (109) is continually monitored and the compressor off (thus engine off) is continued till the temperature of the reservoir (109) goes above the upper limit of idle compressor cut off (Tres_idleup) as shown at 118. In such case, an engine start request is sent to the start/stop logic and the compressor (102) and the pump (110) is commanded to switch ON as shown at 119. If ignition is switched off or the user is not demanding cooling, then the logic will switch off the coolant pump (110). When the temperature of the coolant in the reservoir (109) is between the upper and lower limit, the last compressor (102), the pump (110) and engine state is maintained, i.e. if last state of compressor (102), pump (110) and engine was ON then the this will continue till the temperature goes below lower limit. If last was OFF, this state is maintained till upper limit is reached.

In continuation with FIG.3, if the engine is ON and the user demands cooling and also there is no engine stop request from start/stop logic, then the ECU (112) will check for activation condition. In an embodiment, the operation mode for acceleration and idle compressor cut off and deceleration shall be active only when the temperature of the coolant in the reservoir (109) has reached a certain lower limit (Tres_actvdwn). This is to ensure that the reservoir (109) has sufficiently cold coolant stored, for uninterrupted cooling to user, before starting the acceleration or deceleration mode cut off with AC ON (as shown in FIG.6). If the temperature of the coolant in the reservoir (109) is above the upper limit of activation threshold (Tres_actvup), the compressor (102) and the coolant pump (110) are kept ON as shown at 120. If the temperature is between the upper and lower limits then the last active state of logic is continued i.e. the acceleration or deceleration logics with AC ON will be kept activated if last state was active or will be kept deactivated if last state was deactivated.

In FIG.3, if the engine is ON and the user does not demand cooling, then the flowchart will follow the path as shown in location ‘B’ i.e. AC off deceleration path (as shown in FIG.5). This will ensure the coolant in the reservoir (109) is maintained at a low temperature during AC off conditions (i.e. no user demand for cooling). This will ensure that the coolant in the reservoir (109) is kept sufficiently cold so that immediate cold air is available when user will next demand cooling. The compressor (102) will only be engaged during braking conditions when regenerative energy is available in through the regenerative energy source (113) i.e. when the vehicle kinetic energy is available. The regenerative energy source (113) may be coupled to the compressor (102) and the compressor (102) may be selectively disengaged from the engine
(103) of the vehicle. During braking, if the user has not operated the gear to neutral or has not pressed clutch pedal then the ECU (112) will cut off fuel and the vehicle and engine speed slows down by vehicle inertia only. Thus the vehicle is effectively driving the engine and also the AC compressor (102). By keeping the coolant in the reservoir (109) cold during AC off, will allow to the compressor (102) to spend less useful work (i.e. when no waste energy is present) in bringing the reservoir (109) to sufficiently cold conditions.

The current compressor cut off and cut in temperature thresholds of coolant in the reservoir (109), (Tres_currup & Tres_currdwn) respectively are updated to corresponding values (Tres_decelup & Tres_deceldwn), whenever a deceleration condition is detected (i.e. braking). These values are then used to engage and disengage the compressor (102) as shown in the flowchart C1 (refer FIG.7).

In FIG.3 if the engine is ON and there is user demand for cooling and the coolant in the reservoir (109) has reached sufficient cold temperature (activation condition), then the logic will go to location ‘C’ i.e. AC ON compressor control (refer FIG.6). In this part, the logic will check for current operating mode of vehicle (idle, acceleration or deceleration). Depending on the active mode the current compressor cut off and cut in reservoir temperature thresholds, (Tres_currup & Tres_currdwn) respectively are updated to respective values as mentioned in FIG.6. These values are then used to engage and disengage the compressor (102) as shown in the logic C1 (refer FIG.7).

In another embodiment, in AC ON compressor cut off/cut logic (FIG.6), the said temperature bands (FIG.2) for compressor control (Tres) can also be replaced with cooler air out temperature and same functionality can be achieved. This configuration is useful to control air out temperature from grill which is one of main indicator for user comfort condition.

This system can also be used in battery electric vehicles where an electric compressor can be cycled according to the aforementioned logic. In normal case during deceleration (i.e. braking), the brake energy that is regenerated and stored in the battery will be used in future for driving the electric compressor that will cool the secondary loop coolant and store the cold energy in the reservoir. In the present disclosure, some part of this regenerated energy during braking will charge the traction battery and remaining part will be directly passed on to drive the compressor, that will cool the secondary loop coolant and store the energy inside reservoir as cold heat. In this way we will be removing the inefficiencies that could have been generated during the normal case of traction battery driving the compressor. Thus we will save the battery discharge energy by leveraging the inherent advantages of secondary loop system when user demands cooling. The impact of this will increase the all-electric range of battery electric vehicle.

In an embodiment of the disclosure, the ECU (112) may be a centralized control unit or a dedicated control unit associated with the charging system of the vehicle. The control unit may be implemented by any computing systems that is utilized to implement the features of the present disclosure. The control unit may be comprised of a processing unit. The processing unit may comprise at least one data processor for executing program components for executing user- or system-generated requests. The processing unit may be a specialized processing unit such as integrated system (bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc. The processing unit may include a microprocessor, such as AMD Athlon, Duron or Opteron, ARM’s application, embedded or secure processors, IBM PowerPC, Intel’s Core, Itanium, Xeon, Celeron or other line of processors, etc. The processing unit may be implemented using a mainframe, distributed processor, multi-core, parallel, grid, or other architectures. Some embodiments may utilize embedded technologies like application-specific integrated circuits (ASICs), digital signal processors (DSPs), Field Programmable Gate Arrays (FPGAs), etc.

In some embodiments, the ECU (112) may be disposed in communication with one or more memory devices (e.g., RAM, ROM etc.) via a storage interface. The storage interface may connect to memory devices including, without limitation, memory drives, removable disc drives, etc., employing connection protocols such as serial advanced technology attachment (SATA), integrated drive electronics (IDE), IEEE-1394, universal serial bus (USB), fiber channel, small computing system (108) interface (SCSI), etc. The memory drives may further include a drum, magnetic disc drive, magneto-optical drive, optical drive, redundant array of independent discs (RAID), solid-state memory devices, solid-state drives, etc.

Furthermore, one or more computer-readable storage media may be utilized in implementing embodiments consistent with the present disclosure. A computer-readable storage medium refers to any type of physical memory on which information or data readable by a processor may be stored. Thus, a computer-readable storage medium may store instructions for execution by one or more processors, including instructions for causing the processor(s) to perform steps or stages consistent with the embodiments described herein. The term “computer-readable medium” should be understood to include tangible items and exclude carrier waves and transient signals, i.e., are non-transitory. Examples include random access memory (RAM), read-only memory (ROM), volatile memory, non-volatile memory, hard drives, CD ROMs, DVDs, flash drives, disks, and any other known physical storage media.

It is to be understood that a person of ordinary skill in the art may develop an air conditioning system of similar configuration without deviating from the scope of the present disclosure. Such modifications and variations may be made without departing from the scope of the present invention. Therefore, it is intended that the present disclosure covers such modifications and variations provided they come within the ambit of the appended claims and their equivalents.

Equivalents:

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.

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.” 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.

Referral Numerals:

100 Air-conditioning system
101 Primary loop
102 Compressor
103 Engine
104 Condenser
105 Receiver-dryer
106 Chiller
107 Thermal expansion valve
108 Secondary loop
109 Reservoir
110 Coolant pump
111 Cooler
112 Electronic Control Unit (ECU)
113 Regenerative energy source
114 By-pass valve
115 Temperature sensor
116-120 Flowchart steps