Claims:
1. A method for operating an air-conditioning system (70) of a vehicle, the method comprising:
receiving, by a control unit (10) of the vehicle, temperature of an engine coolant and ambient temperature, from one or more sensors (20) associated with the control unit (10), when an ignition of the vehicle is operated to ON condition;
comparing, by the control unit (10), the temperature of the engine coolant with the ambient temperature; and
operating, by the control unit (10), a compressor (90) of the air-conditioning system (70) based on the comparison, upon receiving a trigger signal to operate the air-conditioning system (70).

2. The method as claimed in claim 1, wherein the comparison by the control unit (10) includes determining a difference between the ambient temperature and the temperature of the engine coolant.

3. The method as claimed in claim 2, wherein the control unit (10) is configured to operate the compressor (90) of the air-conditioning system (70) in a normal mode, or a safe mode based on the difference.

4. The method as claimed in claims 1 and 3, wherein the control unit (10) is configured to operate the compressor (90) of the air-conditioning system (70) in the normal mode, when the difference between the ambient temperature and the temperature of the engine coolant is more than a pre-set threshold.

5. The method as claimed in claims 1 and 3, wherein the control unit (10) is configured to operate the compressor (90) of the air-conditioning system (70) in the safe mode, when the difference between the ambient temperature and the temperature of the engine coolant is lesser than a pre-set threshold.

6. The method as claimed in claim 5, wherein operating the compressor (90) of the air-conditioning system (70) in the safe mode, comprises:
determining, by the control unit (10), an engine speed; and
actuating, by the control unit (10), a relay (80) of the compressor (90) intermittently for a predefined time period within a defined time window, based on the determined engine speed.

7. The method as claimed in claim 6, wherein the predefined time period is based on the engine speed.

8. The method as claimed in claim 6, wherein the defined time window ranges from 1 seconds to 10 seconds with a predefined frequency of ON/ OFF cycle.

9. The method as claimed in claim 1, wherein the control unit (10) is further configured to:
receive, a current time and date data upon receiving the trigger signal to operate the air-conditioning system (70);
retrieve, the time and date data corresponding to previous trigger signal received for operating the air-conditioning system (70);
compare, the received data with the retrieved data; and
operate, the compressor (90) of the air-conditioning system (70) in a normal mode or a safe mode based on the comparison.

10. A system (1) for operating an air-conditioning system (70) of a vehicle, the system (1) comprising:
a control unit (10) associated with the air-conditioning system (70), the control unit (10) is configured to:
receive, an engine coolant temperature and ambient temperature, from one or more sensors (20) associated with the control unit (10), when an ignition of the vehicle is operated to ON condition;
compare, the temperature of the engine coolant with the ambient temperature; and
operate, a compressor (90) of the air-conditioning system (70) based on the comparison, upon receiving a trigger signal to operate the air-conditioning system (70).

11. The system (1) as claimed in claim 10, wherein the control unit (10) is configured to:
determine, a difference between the ambient temperature and the temperature of the engine coolant; and
operate, the compressor (90) of the air-conditioning system (70) in a normal mode or a safe mode based on the difference, wherein:
the compressor (90) of the air-conditioning system (70) is operated in the normal mode, when the difference between the ambient temperature and the temperature of the engine coolant is more than a pre-set threshold, or
the compressor (90) of the air-conditioning system (70) is operated in the safe mode when the difference between the ambient temperature and the temperature of the engine coolant is lesser than a pre-set threshold.

12. The system (1) as claimed in claim 11, wherein the control unit (10) operates the compressor (90) of the air-conditioning system (70) in the safe mode by:
determining, an engine speed; and
actuating, a relay (80) of the compressor (90) intermittently for a predefined time period within a defined time window, based on the determined engine speed.

13. The system (1) as claimed in claim 10, wherein the control unit (10) is further configured to:
receive, a current time and date data upon receiving the trigger signal to operate the air-conditioning system (70) from a real-time clock associated with the vehicle;
retrieve, the time and date data corresponding to previous trigger signal received for operating the air-conditioning system (70);
compare, the received data with the retrieved data; and
operate, the compressor (90) of the air-conditioning system (70) in a normal mode or a safe mode based on the comparison.

14. A vehicle comprising a system (1) for operating an air-conditioning system (70) as claimed in claim 10.
, Description:This application is a patent of addition of the Indian patent application No: 1207/MUM/2013 filed on 28th March 2013.

TECHNICAL FIELD

[001] Present disclosure generally relates to the field of automobiles. Particularly, but not exclusively, the present disclosure relates to an air-conditioning system of a vehicle. Further, embodiments of the present disclosure disclose a method and a system for operating a compressor of an air-conditioning system to improve its durability.

BACKGROUND OF THE DISCLOSURE

[002] Vehicle air-conditioning systems are aimed at providing comfortable and conducive conditions to the passengers inside the vehicle. When external environment conditions are not favourable, for example, too warm or too humid, the air-conditioning system alters the temperature of a particular space or a closure, like a passenger cabin of a vehicle. Alteration in this context is essentially an adjustment or correction of the temperature and the humidity, which are sufficient for human comfort. This is attained by circulating a refrigerant through the air-conditioning loop, which thermally interacts with the passenger cabin. The refrigerant which is in two phases absorbs heat from the passenger cabin in an evaporating unit, where it changes to a vapourized phase. The vapourized refrigerant passes further in the air-conditioning loop into a compressor, where it is compressed to a higher temperature and pressure. The vaporized refrigerant at high temperature and pressure then moves to a condenser where it loses heat to surroundings, and condenses back to its original state. The condensed refrigerant then expands in an expansion unit, and the cycle repeats. A blower is provided in air-conditioning system to blow the cooled air back into the passenger cabin.

[003] Conventionally, operation of the air-conditioning unit, particularly the compressor is cut-off once desired temperature and humid conditions are reached inside the vehicle cabin. This may be achieved by decoupling the power source from the air-conditioning unit. When the temperature of the vehicle cabin rises again, the compressor will be reactivated via a switch or a relay or a mechanical clutch. US Patent publication No. US20170291472 (hereafter referred to as 472’ application) discloses a method of controlling compressor torque and displacement, using an error between the actual evaporator temperature and expected evaporator temperature. Based on the error, output of the compressor is regulated to meet the fluctuating temperature conditions inside the vehicle. Such systems may have limitations such as insensitivity to small fluctuations in the evaporator temperature, which may hamper the efficiency of the air-conditioning unit. The frequent fluctuation in compressor displacement and torque might also pose problems like loss of refrigerant, which may compel compressor to run in an oil starved condition, eventually damaging the compressor. Especially, when the engine is running high speeds with generation of lot of heat, and if the compressor is deriving power directly from the engine, the adverse effects could be acute. Mixing of refrigerant with the lubricating oil of the compressor is another process associated with the air-conditioner operation. If the air-conditioner is not operated for a prolonged duration, for example, prolonged winter weather conditions, during export transits, etc., essential internal parts of the compressor may be deprived of lubricating oil, due to various reasons. One such reason is settling of the lubricating oil at the bottom of the compressor, far away from the moving parts of compressor. Start of the engine after such prolonged time involves tendencies of revving the engine at high speeds when the vehicle is stationary, and switching the AC ON happens in engine revved-up conditions leading to immense heat generation in the compressor, due to lack of lubrication. This is undesirable as it leads to seizure/ failure of AC compressor.

[004] The present disclosure is directed to overcome one or more limitations stated above or other such limitations associated with the prior art.

SUMMARY OF THE DISCLOSURE

[005] One or more shortcomings of conventional systems are overcome, and additional advantages are provided through the method and 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 disclosure are described in detail herein and are considered as a part of the claimed disclosure.

[006] In one non-limiting embodiment of the disclosure, a method for operating an air-conditioning system of a vehicle is disclosed. The method includes receiving, by a control unit of the vehicle, temperature of an engine coolant and ambient temperature from one or more sensors associated with the control unit, when an ignition of the vehicle is operated to ON condition. Then, the control unit compares the temperature of the engine coolant with the ambient temperature, and operates a compressor of the air-conditioning system based on the comparison, upon receiving a trigger signal to operate the air-conditioning system.

[007] In an embodiment of the disclosure, the comparison by the control unit includes determining a difference between the ambient temperature and the temperature of the engine coolant. Further, the control unit is configured to operate the compressor of the air-conditioning system in a normal mode, or a safe mode based on the difference.

[008] In an embodiment of the disclosure, the control unit is configured to operate the compressor of the air-conditioning system in the normal mode, when the difference between the ambient temperature and the temperature of the engine coolant is more than a pre-set threshold. Also, the control unit is configured to operate the compressor of the air-conditioning system in the safe mode, when the difference between the ambient temperature and the temperature of the engine coolant is lesser than a pre-set threshold.

[009] In an embodiment of the disclosure, operating the compressor of the air-conditioning system in the safe mode by the control unit includes determining an engine speed. Then, the control unit actuates a relay of the compressor intermittently for a predefined time period within a defined time window, based on the determined engine speed.

[010] In an embodiment of the disclosure, the predefined time period is based on the engine speed, and the defined time window ranges from 1 second to 10 seconds with a predefined frequency of ON/ OFF cycle.

[011] In an embodiment of the disclosure, the control unit is further configured to receive a current time and date data upon receiving the trigger signal to operate the air-conditioning system. Then, control unit retrieves the time and date data corresponding to previous trigger signal received for operating the air-conditioning system, and compares the received data with the retrieved data. Further, the control unit operates the compressor of the air-conditioning system in a normal mode, or a safe mode based on the comparison.

[012] In another non-limiting embodiment of the disclosure, a system for operating an air-conditioning system of a vehicle is disclosed. The system includes a control unit associated with the air-conditioning system. The control unit is configured to receive, an engine coolant temperature and ambient temperature from one or more sensors associated with the control unit, when an ignition of the vehicle is operated to ON condition. Then, the control unit compares the temperature of the engine coolant with the ambient temperature. Further, the control unit operates a compressor of the air-conditioning system based on the comparison, upon receiving a trigger signal to operate the air-conditioning system.

[013] In an embodiment of the disclosure, the control unit is configured to determine a difference between the ambient temperature and the temperature of the engine coolant. Then, the control unit operates the compressor of the air-conditioning system in a normal mode, or a safe mode based on the difference. The compressor of the air-conditioning system is operated in the normal mode, when the difference between the ambient temperature and the temperature of the engine coolant is more than a pre-set threshold. Also, the compressor of the air-conditioning system is operated in the safe mode when the difference between the ambient temperature and the temperature of the engine coolant is lesser than a pre-set threshold.

[014] In an embodiment of the disclosure, the control unit operates the compressor of the air-conditioning system in the safe mode by determining an engine speed. Then, the control unit actuates a relay of the compressor intermittently for a predefined time period within a defined time window, based on the determined engine speed.

[015] In an embodiment of the disclosure, the control unit is further configured to receive a current time and date data upon receiving the trigger signal to operate the air-conditioning system, from a real-time clock associated with the vehicle. Then, the control unit retrieves the time and date data corresponding to previous trigger signal received for operating the air-conditioning system, and compares the received data with the retrieved data. The control unit operates the compressor of the air-conditioning system in a normal mode, or a safe mode based on the comparison.

[016] 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.

[017] 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 ACCOMPANYING DRAWINGS

[018] The novel features and characteristics of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of an 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:

[019] FIG. 1 illustrates block diagram of a system for operating an air-conditioning system of a vehicle, in accordance with an embodiment of the present disclosure;

[020] FIG. 2 is a flowchart illustrating a method by which the air-conditioning system of FIG. 1 is operated, in accordance with an embodiment of the present disclosure; and

[021] FIG. 3 is a detailed flowchart illustrating a method of operating a compressor of the air-conditioning system in normal mode or safe mode, in accordance with an embodiment of the present disclosure.

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

DETAILED DESCRIPTION

[023] While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have 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.

[024] It is to be noted that a person skilled in the art would be motivated from the present disclosure and modify various features of the system and the method, without departing from the scope of the disclosure. Therefore, such modifications are considered to be part 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 skilled in the art having benefit of the description herein. Also, the system of the present disclosure may be employed in variety of vehicles such as passenger vehicles, commercial vehicles having different specifications. However, the engine, the air-conditioning unit and other components associated with the engine and the air-conditioning unit are not illustrated in the drawings of the disclosure for the purpose of simplicity.

[025] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover non-exclusive inclusions, such that a method or a system or an assembly or a device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such a method, a system, or an assembly or a device. In other words, one or more elements in the method or the system or the assembly or the device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the method or the system or the assembly or the device.

[026] Embodiments of the present disclosure disclose a method and a system for operating an air-conditioning (alternately referred to as AC system in the specification) system of a vehicle, intended to improve compressor durability. The system incorporates a control unit which may receive data, such as temperature of a coolant circulating in the engine compartment, as well as ambient temperature conditions in which the vehicle is operating. The control unit may be communicatively associated with one or more sensors to receive the engine coolant temperature and ambient temperature data. Also, receiving of the engine coolant and ambient temperature data may happen immediately after an ignition of the vehicle is turned ON and before the engine is cranked. Once both the temperature values are input to the control unit by the one or more sensors, the control unit makes a comparison and stores the same. The control unit upon receiving a trigger signal to operate the air-conditioning system, operates the compressor of the air conditioning system in a specific operational mode.

[027] The method also encompasses acts or steps of operating the compressor in a normal mode or in a safe mode based on several input conditions. One of the key input conditions is the difference between the engine coolant temperature and the ambient temperature determined by the control unit, upon receiving temperature values from the one or more sensors. If the difference between the engine coolant temperature and the ambient temperature is lesser than a pre-set threshold, a safe mode of operation of the compressor is activated. On the other hand, if the difference is more than the pre-set threshold, a normal mode of operation is initiated. Both safe mode and normal mode operations may be regulated by the control unit. An another input the control unit considers for operating the compressor in the safe mode is the engine speed input. Upon receiving the engine speed input, the control unit actuates a relay associated with the compressor in the AC system. The relay associated with the compressor is actuated on intermittent basis for a predefined time period and within a definite time window, both of which are dependent on the engine speed input. Further, the predefined time period may vary inversely with the engine speed. For example, at high speeds, the compressor may be activated via the relay for a brief period of time, and then deactivated for a definite time window. In an embodiment, the predefined time period is based on the engine speed, and the defined time window ranges from 1 second to 10 seconds with a predefined frequency of ON/ OFF cycle.

[028] Further, in an embodiment, the control unit may receive real-time (current) date and time as input from the real time clock associated with the vehicle to vary the operational characteristics of the compressor. Accordingly, the compressor may retrieve previous activation time and date data from associated components such as memory unit (for ex., PROM, EPROM, EEPROM etc.). The control unit is also fed with time and date data corresponding to current activation the compressor, by a real-time clock interfaced with the control unit. The control unit compares both received input data and retrieved data, and decides whether to operate the compressor in the safe mode or in the normal mode. In an embodiment, the normal mode of compressor operation corresponds to default logic programmed in the AC system (or HVAC system). The operational mode which considers difference between the engine coolant temperature and ambient temperature, may be useful for vehicles which do not have real-time clock input data.

[029] The following paragraphs describe the present disclosure with reference to FIGS.1 to 3. In the figures, the same element or elements which have similar functions are indicated by the same reference signs.

[030] FIG. 1 portrays a block diagram of the system (1) for operating an air-conditioning (AC) system (70) of a vehicle (not shown). An AC system (70) may be integrated in the vehicle in communication with the control unit (10). The control unit (10) may include, but not limited to, an Electronic Control Unit (ECU) associated with Engine Management System (EMS) of the vehicle. The control unit (10) in accordance with the present disclosure, may be configured to interact with several modules, like Inputs and Outputs, as shown in the block diagram. However, one should not construe the arrangement shown in FIG. 1 as the only possible configuration, as the system (1) may include several other components and modules which perform various functions within a vehicular topography. As shown in FIG. 1, the control unit (10) may be communicatively coupled with various Input modules, or simply, Inputs. The Inputs include various sensors (20) which may detect variety of conditions with respect to the vehicle anatomy, such as, but not limited to engine speed, temperatures of coolant, ambient temperature, passenger cabin temperature, engine temperature, fuel temperature, pressures in various fluid lines, etc.

[031] In accordance with the embodiments of the present disclosure, the control unit (10) may receive signals corresponding to engine coolant temperature, and ambient temperature in which the vehicle remains in that time instant. In an embodiment, the temperature sensors include but not limited to Resistance Temperature Detectors (RTD), Thermistors, Semiconductor based sensors, Molecular change-of-state sensors, infrared and bimetallic sensors and so on. The engine coolant temperature sensor and ambient temperature sensor may already be present in the vehicle (in case of present-day top-tier models), or may be externally interfaced with existing electronic system of the vehicle for temperature detection. The engine coolant temperature and ambient temperature values detected by the sensors (20) are input to the control unit (10) via input line (25), in analog or digital format depending on the requirement. The engine coolant may circulate through all the components defined in the cooling system of the engine, and remove heat from crucial sections of the engine to prevent overheating. The sensors (20) may be configured in such a way that they may start detection of engine coolant temperature and ambient temperature, as soon as the ignition of the vehicle is turned ON.

[032] Further, upon receiving engine coolant temperature and ambient temperature data, the control unit (10) may compare both the temperatures, and calculate the difference between them. In other words, the control unit (10) determines the deviation of engine coolant temperature from the ambient temperature, which may give an indication of vehicle non-usage duration. For example, if the difference between engine coolant and ambient temperature is zero or very close to zero, the control unit (10) decides that the engine has not been turned ON for extended duration of time, for example, 15 days or more. Usually, a deviation of temperature difference (between engine coolant and ambient) with respect to a pre-set threshold value is determined. In an embodiment, the pre-set threshold value may be stored in a memory unit (60) coupled with the control unit (10), and the control unit (10) may map the temperature difference (engine coolant and ambient) on to the pre-set threshold value to make a comparison. Based on the temperature difference, the control unit (10) decides whether to operate the AC system (70), specifically the compressor (90), in a normal mode or in a safe mode. The choice of control unit (10) to operate the compressor (90) in normal mode or safe mode is necessary to prevent dry running of the compressor (90), due to absence or insufficient lubricant to lubricate the compressor (90) after long non-usage periods. In an embodiment, the control unit (10) activates safe mode operation if the difference between engine coolant temperature and ambient temperature is lesser than a pre-set threshold. If the difference is more than the pre-set threshold, normal mode of operation is commenced.

[033] Further, as shown in FIG. 1, the control unit (10) may include power supply module (35) to power the hardware components in it. In addition, the control unit (10) may have other inputs such as frequency inputs, which are encoder type inputs like crank, vehicle speed, engine speeds etc. One or more discrete inputs, which are basically ON/OFF type inputs (logical) may also be present. In the present disclosure, ignition ON condition may be given as discrete input to the control unit (10). The control unit (10) may include various entities within it to receive and process (like encode/decode) the inputs. For instance, as shown in FIG. 1, the control unit (10) may include power supply (35) segment which may be electrically coupled to main supply (30), and so on. The frequency, discrete and other signals which may fall in the same category may be given to the module (40) within the control unit (10) from external sources. Accordingly, the control unit (10) may receive trigger signal to operate the AC system (70) once comparison between engine coolant temperature and ambient temperature is made. Additionally, the control unit (10) may be coupled to flags (for monitoring and selecting suitable states for the instruction execution cycle) and clock (for timing and control). Other inputs like engine speed, activation time (current and previous) of various components including the AC compressor (90) may be fetched by the control unit (10).

[034] The control unit (10) present in the system (1) may also be associated with a memory unit (60) in a two-way communication mode to send and receive data. The output of the control unit (10), as shown in FIG. 1, is limited to regulation of output parameters of an AC system (70). However, in a vehicle, the control unit (10) may be linked to regulation of various output parameters such as fuel injection, coolant circulation, drive-mode selection, engine output based on fuel levels, and the like, in addition to regulation of AC system (70) as shown in FIG. 1.

[035] Reference is now made to FIG. 2 which illustrate an operational embodiment of the present disclosure. Reference is also made to FIG. 1 in conjunction with FIG. 2 to illustrate the operational embodiment. As shown in flowchart (100), the control unit (10) may receive ambient temperature data and engine coolant temperature data from one or more sensors (20), as depicted in step 102. This step may be initiated after the ignition is turned ON in step 101. After the temperature values are received, the control unit (10) compares both the values to find the difference. Once the comparison step 103 is concluded, the control unit (10) may initiate engine start, followed by turning the AC system (70) ON upon receiving a trigger signal. In an embodiment, the trigger signal may be received from a switch (not shown) associated with the air conditioning system (70) of the vehicle. The comparison in step 103 may lead to finding the difference between ambient temperature and engine coolant temperature, as in step 104. This difference may be used by the control unit (10) to make a decision whether to operate the AC compressor (90) in a safe mode or in a normal mode. If the difference determined in step 104 is more than a pre-set threshold, normal mode of operation of the compressor (90) may be initiated. Normal mode of operation 106 of the compressor (90) or AC system (70) as a whole corresponds to default AC operation with usual compressor (90) output. Control unit (90) selects normal mode of operation 107 of AC system (70) based on the temperature difference higher than the pre-set threshold, indicative of a recent engine ON condition, and presence/sufficiency of lubricant to lubricate the compressor (90) parts. The safe mode operation 107, on the other hand, is opted by the control unit (10) when the temperature difference is lesser than the pre-set threshold. The temperature difference in such a scenario may be equal to zero (same ambient and engine coolant temperatures), or close to zero. The temperature difference smaller than pre-set threshold is indicative of long-duration non-operated condition of the engine, rendering the compressor (90) to starve of lubricant or face inadequacy of lubricant. Both these conditions may lead to overheating of the compressor (90), eventually leading to its failure, especially during high-engine revving after a long duration of engine inactivity. The safe mode operation 107 attenuates this problem of long duration inactivity of the engine by intermittently operating the compressor (90). To bring about intermittent compressor (90) activation, the control unit (10) fetches engine speed input as per step 108 from one or more sensors (20). Based on engine speed, the control unit (10) decides the predefined time period for which the compressor (90) needs to be activated (like a warm up operation). The activation for predefined time is attained through a relay (80) or a switch, and is followed by deactivation of the compressor (90) for a definite time interval. The activation and deactivation process is indicated in step 109. The activation and deactivation may be carried out for a predetermined number of cycles for a definite time window. For example, for an engine speed lesser than 2000 RPM, safe mode operation may involve activating (engaging) the compressor for 1 second, followed by deactivation (disengaging) for 10 seconds. This activation-deactivation may go on for 3 cycles or 4 cycles in the safe mode, and the corresponding values may be used for calibration of data for future use. The intermittent activation of the compressor (90) allows the compressor (90) to undergo lubrication slowly at lower speeds, so that heat generated by the compressor (90) operation is kept minimal. This way, damage of compressor (90) may be avoided.

[036] FIG. 3 is a flowchart illustrating an extended operational mode of the method described with respect to FIG. 2 above. According to this embodiment, once the temperature difference between engine coolant and ambient conditions (step 203) is determined, engine start is initiated. This is followed by switching on the AC system (70), both depicted by step 202. The temperature difference of step 203, as well as engine and AC ON signal of step 202 may be used to determine whether a compressor (90) durability logic is enabled in the control unit (10), as indicated by step 204. The compressor (90) durability logic includes program sequences intended to regulate the compressor (90) operation, so as to increase its durability. The compressor (90) durability logic may include determining, retrieval and comparison of current and previous time-date statistics of engine operation. This feature, known as telematics, may or may not be configured in the vehicles of all segments. The vehicles which are equipped with telematics make use of compressor (90) durability logic to determine engine inactivity condition, and the duration of engine inactivity. On the other hand, the vehicles devoid of telematics may be equipped with temperature difference data logic, where the difference of ambient temperature and engine coolant temperature of step 207 comes into picture. The temperature difference data logic, as already discussed in previous paragraphs, may lead to activation of one of safe mode and normal mode.

[037] The absence of compressor (90) durability logic may lead to normal mode of operation of the AC system (70), as per step 205. If the time and date frame logic corresponding to compressor durability logic is enabled in the control unit (10), it leads to time and date comparison of engine activation at present and in the past. Accordingly, as depicted in step 208, the control unit (10) fetches real-time date and time data of the engine operation. Simultaneously, control unit (10) also fetches date and time data when the engine was operated for the last time, for example, 3 days ago or 15 days ago or months ago. If such a data (previous data) is not available (step 210), or if there is an error in retrieval/analysis of such data, the control unit (10) proceeds with saving the current activation time and date data in the memory (60) and, activate normal mode as in step 213. If the real-time and previous engine activation date-time data is available (step 210), then the control unit (10) compares the real-time data with the previous data to find a difference, as per step 211. For example, if real-time data is 12th March, 12:00:00 hours and previous data is 28th February, 12:00:00 hours, then the difference of 12 days or 13 days, 0 hours is determined and stored. If the difference results to a value closer to zero or equal to zero, i.e., current activation time and previous activation time is almost the same, then the normal mode is activated as per step 205. Else, the comparison is made on the basis of calibrated data, as in step 212. In step 212, if the difference between current activation time and previous activation time is lesser than calibrated date and time data, say 15 days or 30 days, then the present date and time data is stored in the memory (60), and then normal mode is activated as per step 213. This indicates that previous engine activation relative to current activation is safe enough to provide sufficient lubrication to the compressor (90) to operate the compressor (90) in its regular operational mode. If the difference between the current engine activation date-time and previous engine activation date-time is greater than the calibrated date and time data, the present date and time data is stored in the memory (60), and safe mode (step 209) of the AC (70) operation is initiated to protect the compressor (90). The safe mode operation is on the basis of the indication that engine has been inactive for longer duration of time, and normal mode of operation of the AC system (70) would hamper the compressor (90) with the engine operation.

[038] The method and the system in accordance with some embodiments of the present disclosure, has several advantages. One advantage is that the system can be easily integrated with vehicles where direct detection of engine inactivity (extended) period is not possible. Another advantage of having the system or incorporating the method in a vehicle, is that the vehicle need not have telematics to detect current and previous engine activation date-time data. Since most of the vehicles make use of coolants in the engine compartment and have the infrastructure to determine ambient temperature, determining difference between the coolant and ambient temperatures is more convenient, feasible, economical and does not require complicated logic. A further advantage is real-time correction or regulation of compressor output based on determined temperature difference. Even with small fluctuations of engine coolant temperature or ambient temperature, the compressor activation mode may be decided so that safe and reliable functioning of the compressor is ensured all the time.

[039] In an embodiment of the disclosure, the control unit (10) (like an ECU) may be a centralized control unit, or a dedicated control unit associated with the Air-conditioning system of the engine. 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.

[040] In some embodiments, the ECU 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 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.

[041] It is to be understood that a person of ordinary skill in the art may develop a 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:

[042] 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.

[043] 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 (108) 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 (108) 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 being indicated by the following claims.

Reference Numerals:

System 1
Control unit 10
Inputs to Control unit 20
Analog/Digital Input line 25
Main Supply to control unit 30
Power supply segment 35
Frequency/Discrete input module 40
Time and date input module 50
Memory unit 60
Air-conditioning system 70
Relay 80
Compressor 90
Method steps 100-109
Extended method steps 200-212