Description:TECHNICAL FIELD
[001] Embodiments disclosed herein relates to the field of refrigeration and automobiles, and more particularly to methods and systems for maintaining cooling performance and diagnosing refrigerant leakage in a vehicle.

BACKGROUND
[002] In vehicles, a refrigerant cools the coolant in a chiller, which keeps the battery of the electric vehicle cool. In case of a refrigerant leakage, the leakage can impact the cooling of the battery and cause battery overheating. Due to the overheating of the battery, the vehicle may be immobilized, or if the vehicle ignition is not turned off, the vehicle shall be in an unsafe driving condition with an overheated battery.

OBJECTS
[003] The principal object of embodiments herein is to disclose methods and systems for maintaining cooling performance and diagnosing refrigerant leakage(s) in an electric vehicle.
[004] Another object of embodiments herein is to disclose methods and systems for maintaining cooling performance and diagnosing refrigerant leakage(s) and coolant leakage(s) inside a cooling system of an electric vehicle when an ignition of the vehicle is turned on.
[005] Another object of embodiments herein is to disclose methods and systems for maintaining cooling performance and diagnosing refrigerant leakage(s) in an electric vehicle, when the first value of pressure is determined as higher than a first fractional value of the threshold pressure value and the ignition of the vehicle is turned ON.
[006] Another object of embodiments herein is to disclose methods and systems for raising an alarm with a low refrigerant indication to notify an occupant of the vehicle and turn the ignition of the vehicle ON, when the first value of pressure is determined to be lower than a first fractional value of the threshold pressure value.
[007] Another object of embodiments herein is to disclose methods and systems for raising an alarm with an unsafe to drive indication to notify an occupant of the vehicle and turn the ignition of the vehicle ON when the first value of pressure is detected to be lower than a second fractional value of the threshold pressure value.
[008] Another object of embodiments herein is to disclose methods and systems for maintaining cooling performance and diagnosing refrigerant leakage in an electric vehicle, by keeping the ignition of the vehicle OFF when the first value of pressure is lower than a third fractional value of the threshold pressure value.
[009] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating at least one embodiment and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF FIGURES
[0010] Embodiments herein are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0011] FIG. 1A shows a schematic diagram of a refrigeration system of a vehicle, according to embodiments as disclosed herein;
[0012] FIG. 1B shows a block diagram of a refrigeration system of a vehicle, according to embodiments as disclosed herein;
[0013] FIG. 2A is an example schematic diagram for the positioning of an ambient temperature sensor in a vehicle, according to embodiments as disclosed herein;
[0014] FIG. 2B is an example schematic diagram for the positioning of a sun load sensor in the vehicle, according to embodiments as disclosed herein;
[0015] FIG. 3 shows a block diagram for a system for maintaining cooling performance and diagnosing refrigerant leakage, according to embodiments as disclosed herein;
[0016] FIG. 4 is a flowchart depicting a method (400), for maintaining cooling performance and diagnosing refrigerant leakage, according to embodiments as disclosed herein; and
[0017] FIG. 5 is a flowchart depicting a method (600), for maintaining cooling performance and diagnosing refrigerant leakage, according to embodiments as disclosed herein.
DETAILED DESCRIPTION
[0018] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0019] The embodiments herein achieve a method and a system for maintaining cooling performance and diagnosing refrigerant leakage in vehicle. Referring now to the drawings, and more particularly to FIGS. 1 through 5, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0020] The term “vehicle” as referred herein is a thing to transport people, or goods. The vehicle may be at least one of a car, bus, truck, lorry etc. The vehicle may be run by an engine, a battery, or a combination of both (i.e., the engine and the battery). The engine may be an internal combustion engine. The vehicle run by engine as well as a battery are known as hybrid vehicles.
[0021] FIG. 1A and 1B shows a schematic diagram of a refrigeration system of a vehicle, according to embodiments as disclosed herein. The refrigeration system comprises a compressor (104), a condenser (106), an evaporator (102) and an expansion valve (108). The compressor (104), the condenser (106), the evaporator (102) and the expansion valve (108) are connected to each component with tubing or piping that makes it a closed loop system. A suction line connects the evaporator (102) to the compressor (104). A hot gas or discharge line connects the compressor (104) to the condenser (106), and the liquid line is a connecting tubing between the condenser (106) and the expansion valve (108). The system may also comprise a receiver (110) between condenser (106) and the expansion valve (108), wherein the refrigerant may be stored in the receiver (110) until the refrigerant is needed for heat removal in the evaporator (102).
[0022] The compressor (104) controls a flow of the refrigerant by acting as a motor and a pump. The compressor (104) allows the refrigeration system to pressurize the refrigerant and reduce its volume. The type of the compressor may include at least one of, but not limited to, a reciprocating compressor, a rotary compressor, a screw compressor, a centrifugal compressor, and a scroll compressor. The refrigerant entering the condenser is hot and pressurized. The condenser cools the refrigerant and converts the refrigerant into a liquid state. The condenser (106) includes, but is not limited to, at least one of an air cooled condenser, a water cooled condenser and an evaporative condenser.
[0023] The expansion valve (108) helps to reduce the pressure and temperature of the refrigerant. The sudden drop in pressure and temperature produces a cooling effect. The expansion valve (108) also regulates the amount of refrigerant used in meeting the cooling requirements of the load. In an embodiment herein, the load is the battery in the vehicle and space around the battery.
[0024] The evaporator (102) absorbs heat inside the space. The evaporator (102) acts as a medium of exchange for heat from the load to the refrigerant. Here, the refrigerant is cold and moves at a slower pace in order to absorb as much heat as possible from the load. As the refrigerant absorbs the heat, refrigerant gets hotter and turns into a gas. By vaporising the refrigerant, more heat can be absorbed from the load. The refrigerant, now hot and in gaseous form, is then pushed back into the compressor (104). The receiver (110), also referred to as liquid receiver, may store the refrigerant. The receiver (110) can store the refrigerant, when the system is operating at less than its maximum heat load. In general, refrigeration systems with receivers are designed so that the receiver can hold the entire system’s charge and still be no more than 80% full. The design of the receiver allows to pump down the entire system charge into the receiver without the danger of creating hydrostatic pressure; that refers to very high pressures resulting from full liquid expansion.
[0025] The suction line connecting the evaporator (102) and the compressor (104) is a low pressure line. A first pressure sensor (112) is connected in series in the suction line to measure a first pressure value of the refrigeration system. The first pressure sensor (112) senses the pressure of the suction line (i.e., a first pressure value), and provides the first pressure value to the processor of the Heating, Ventilation, and Air Conditioning Electronic Control Unit (HVAC ECU) of the vehicle.
[0026] The discharge line connecting the compressor (104) to the condenser (106) is a high pressure line. A second pressure sensor (114) is connected in series in the discharge line to measure a second pressure value of the refrigeration system. The second pressure sensor senses a pressure of the discharge line (i.e., the second pressure value), and provides the second pressure value to the processor of the HVAC ECU of the vehicle.
[0027] The first pressure sensor and the second pressure sensor may comprise at least one of Aneroid barometer pressure sensors, manometer pressure sensors, bourdon tube pressure sensors, vacuum (Pirani) pressure sensors, sealed pressure sensors, piezoelectric pressure sensors, and strain gauge pressure sensors.
[0028] FIG. 2A shows a schematic diagram for the positioning of an ambient air temperature sensor in a vehicle, according to embodiments as disclosed herein. The ambient air temperature sensor measures the temperature outside the passenger compartment of the vehicle. In an embodiment herein, the ambient air temperature sensor may be mounted inside or near the front bumper of the vehicle. The ambient air temperature sensor provides the measured temperature to the HVAC ECU of the vehicle to help control the interior temperature of the vehicle. In an embodiment herein, the ambient air temperature sensor can also provide the occupants of the vehicle with temperature readings from outside the car. Herein, the measured temperature (as provided by the ambient air temperature sensor) may be utilized for determining a threshold pressure value for an air conditioning system of the vehicle. The HVAC ECU may determine the threshold value of the pressure for an air conditioning system of the vehicle using the measured temperature (as provided by the ambient air temperature sensor) and a sun load sensor.
[0029] FIG. 2B is an example schematic diagram for the positioning of a sun load sensor in the vehicle, according to embodiments as disclosed herein. FIG. 2B shows an example placement of the sun load sensor, wherein the sun load sensor is mounted on the vehicle’s dash near a front windshield. In an embodiment herein, the sun load sensors may be located at the top of the dash and are mounted on a removable plate, speaker grill, or defroster vent. In an embodiment herein, sun load sensors can be placed one on either side of the dash to accommodate differences in sunlight exposure. In an embodiment herein, the sun load sensors may be of a photodiode type, which provides increased resistance as the light intensity increases, so the signal from the sensor drops as the sun shines brighter. In an embodiment herein, the operating range of the sun load sensor is between 0 and 5 volts. As the sun load increases, the voltage decreases. The signal from the sun load sensor is sent to the HVAC ECU. The HVAC ECU can utilize a sun load value from the sun load sensor and the ambient air temperature sensor to determine the threshold pressure value. The threshold pressure value may be a function of the temperature value and the sun load value. The threshold pressure value may be determined from a lookup table as shown in the example in Table 1. The threshold value of the pressure depends on a type of vehicle and varies according to a size and an architecture of the vehicle.
Temperature value Sun load value Threshold value
x y f(x,y)
Table 1
[0030] In an embodiment herein, Table 2 shows a threshold pressure value that is to be determined at a particular temperature and a determined sun load value. For example, at 25℃ temperature value and 300 as the sun load value determined by the sun load sensor, the threshold value determined by the system is 5. And 35℃ as the temperature value and 900 as the sum load value, the threshold value is determined as 7.
Solar load( W/m2) 300 600 900
Temperature(℃)
25 5 6 7
35 6 7 8
45 7 8 9
Table 2
[0031] FIG. 3 shows a block diagram for a system (300) for maintaining cooling performance and diagnosing refrigerant leakage, according to embodiments as disclosed herein. The system (300) comprises the first pressure sensor (112), the second pressure sensor (114), the ambient air temperature sensor (204), the sun load sensor (202), the vehicle ECU (206), and the HVAC ECU (210). The HVAC ECU (210) comprises a processor (211) connected in series in the suction line to measure a first pressure value of the refrigeration system. The HVAC ECU (210) may comprise a memory to save the data or may be connected to a memory to save the data. The vehicle ECU (206) receives the sun load value from the sun load sensor (202), and the temperature value from the ambient air temperature sensor (204). The HVAC ECU (210) receives the sun load value and the temperature value from the vehicle ECU (206). The processor (211) determines the threshold pressure value as the function of the sun load value and the temperature value.
[0032] The processor (211) further receives a first pressure value from the first pressure sensor (112) and a second pressure value from the second pressure sensor (114). The processor (211) determines a third value of pressure from the first value of pressure and the second value of pressure, wherein the third value of pressure is the average value of the first value of pressure and the second value of pressure.
[0033] In an embodiment herein, the processor (211) compares the third value of pressure with a fractional value of the threshold of pressure. If the third pressure value is greater than a first fractional value of the threshold pressure, then the processor (211) may signal the vehicle ECU to turn ON an ignition of the vehicle without any alarm signal. For an example, if the third pressure value is greater than 80% of the threshold pressure value, then the vehicle ignition is turned ON by the vehicle ECU (206).
[0034] In an embodiment herein, if the third pressure value is determined to be lower than the first fractional value of the threshold pressure, then the processor (211) may raise an alarm for low refrigerant indication and the vehicle ignition is turned ON by the vehicle ECU (206). The processor (211) may check if the third pressure value is lower than a range of the second fractional value. For an example, if the third pressure value is lower than 80% and in between 70% to 80% of the threshold pressure value, the processor (211) raises an alarm for low refrigerant indication and the vehicle ignition is turned ON by the vehicle ECU (206). In an embodiment herein, the alarm may be a visual alarm and/or an audio alarm. The alarm may be given on a vehicle infotainment system, a mobile device, and a handheld device. The alarm may be given to an owner of the vehicle remotely on the mobile device or the handheld device. The processor (211) may be in communication with the mobile device through a wireless network. The processor (211) and the mobile device may be an internet of things (IOT) device.
[0035] In an embodiment herein, if the third pressure value is determined to be lower than the first fractional value of the threshold pressure, the processor (211) further checks if the third pressure value is lower than a second fractional value of threshold pressure value. The processor (211) may check if the third pressure value is lower than a range of the second fractional value. If the check is true (i.e., the third pressure value is determined to be lower than the second fractional value of the threshold pressure), then the processor (211) raises an alarm for unsafe driving condition and the processor (211) signals the vehicle ECU (206) to turn ON the vehicle ignition. For example, the processor (211) checks if the average value of pressure is in between 60% to 70% of the threshold pressure value, the processor (211) raises an alarm for unsafe driving conditions and signals the vehicle ECU (206) to turn ON the vehicle ignition.
[0036] In an embodiment herein, if the third pressure value is determined to be lower than the second fractional value of the threshold pressure, the processor (211) further checks if the third pressure value is lower than a third fractional value of threshold pressure value. If the check is true, i.e., the third pressure value is determined to be lower than the third fractional value of the threshold pressure, then the processor (211) raises an alarm for refrigerant leakage and signals the vehicle ECU (206) to keep the vehicle ignition OFF. For example, the processor (211) checks if the average value of pressure is lower than 60% of the threshold pressure value, the processor (211) raises an alarm for refrigerant leakage and signals the vehicle ECU (206) to keep the vehicle ignition OFF.
[0037] In an embodiment herein, the average value of pressure is the average of the first pressure value of the suction line and the second value of pressure of the discharge line. Therefore, if the average value of pressure drops below the threshold pressure value that points towards a leakage in the refrigeration system of the vehicle and there may be a leak in the refrigerant lines in the system. Therefore, by comparing the average value of pressure and the threshold pressure value, the system (300) detects a gas leakage of a refrigerant and a coolant inside a cooling system of a vehicle when an ignition of the vehicle is turned on.
[0038] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The network elements shown in FIG. 3 include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.
[0039] The system (300) detects a gas leakage of a refrigerant and a coolant inside a cooling system of a vehicle when an ignition of the vehicle is turned on. The system (300) particularly works for an Electric Vehicle. However, the implementation of the system is not limited to Electric vehicles and may be implemented on internal combustion engine vehicles and automobiles. The system (300) may perform in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions and blocks listed in FIG. 3 may be omitted.
[0040] FIG. 4 is a flowchart depicting a method (400), for maintaining cooling performance and diagnosing refrigerant leakage, according to embodiments as disclosed herein. FIG. 4 describes a method to detect refrigerant leakage particularly to electric vehicles. At step 402, the vehicle ignition is turned on. At step 404, the vehicle ECU (206) receives the sun load value from the sun load sensor and the temperature value from the ambient air temperature sensor. At step 406, the processor (211) of the HVAC ECU (210) determines the threshold value of the pressure. At step 408, the processor (211) receives a first pressure value from the first pressure sensor (112) and a second pressure value from the second pressure sensor (114). At step 410, the processor (211) determines the third value of pressure, wherein the third value of pressure is the average value of the first pressure value and the second pressure value. At step 412, the third value of pressure is compared with a first fractional value of the threshold value. At step 414, the vehicle ignition is turned ON without any alarm if the average pressure of the refrigeration system is above the permissible limit of the threshold pressure value. At step 416, the processor (211) checks if the third pressure value is lower than the first fractional value of the threshold value. At step 418, if the third pressure value is lower than the first fractional value of the threshold value, then the processor (211) raises an alarm for low refrigerant and turns the vehicle ignition ON. At step 420, the processor (211) checks if the third value of pressure is lower than the second fractional value of the threshold value. At step 422, if the third pressure value, that is the average pressure, is lower than the second fractional value of the threshold value, then the processor (211) raises an alarm for unsafe driving condition and turns the vehicle ignition ON. At step 424, the processor (211) checks if the third value of pressure is lower than the third fractional value of the threshold value. At step 426, if the third pressure value that is the average pressure is lower than the third fractional value of the threshold value, then the processor (211) raises an alarm for refrigerant leakage and keeps the vehicle ignition OFF. The various actions in method 400 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 4 may be omitted.
[0041] FIG. 5 is a flowchart depicting a method (500), for maintaining cooling performance and diagnosing refrigerant leakage, according to embodiments as disclosed herein. FIG. 5 describes a method to detect refrigerant leakage particularly to Internal Combustion Engine vehicles. At step 502, the vehicle ignition is turned on. At step 504, the vehicle ECU (206) receives the sun load value from the sun load sensor and the temperature value from the ambient air temperature sensor. At step 406, the processor (211) of the HVAC ECU (210) determines the threshold value of the pressure. The threshold value depends upon the type of vehicle, the vehicle size and the architecture of the vehicle. At step 508, the processor (211) receives a first pressure value from the first pressure sensor (112) and a second pressure value from the second pressure sensor (114). At step 510, the processor (211) determines the third value of pressure, wherein the third value of pressure is the average value of the first pressure value and the second pressure value. At step 512, the third value of pressure is compared with a first fractional value of the threshold value. At step 514, the vehicle ignition is turned ON without any alarm if the average pressure of the refrigeration system is above the permissible limit of the threshold pressure value. At step 516, the processor (211) checks if the third pressure value is lower than the first fractional value of the threshold value. At step 518, if the third pressure value is lower than the first fractional value of the threshold value then the processor (211) raises an alarm for low refrigerant and turns the vehicle ignition ON. At step 520, the processor (211) checks if the third value of pressure is lower than the second fractional value of the threshold value and is between a range of the second fractional value. At step 522, if the third pressure value that is the average pressure is in between the range of the second fractional value of the threshold value then the processor (211) raises the alarm for unsafe driving condition is raised and turns the vehicle ignition ON. At step 524, if the third pressure value, that is the average pressure, is lower than the range of the second fractional value of the threshold value then the processor (211) raises an alarm for refrigerant leakage and keeps the vehicle ignition OFF.
[0042] The embodiment disclosed herein describes the method and the system for maintaining cooling performance and diagnosing refrigerant leakage in the vehicle. Therefore, it is understood that the scope of the protection is extended to such a program and in addition to a computer readable means having a message therein, such computer readable storage means contain program code means for implementation of one or more steps of the method, when the program runs on a server or mobile device or any suitable programmable device. The method is implemented in at least one embodiment through or together with a software program written in e.g. Very high speed integrated circuit Hardware Description Language (VHDL) another programming language, or implemented by one or more VHDL or several software modules being executed on at least one hardware device. The hardware device can be any kind of portable device that can be programmed. The device may also include means which could be e.g. hardware means like e.g. an ASIC, or a combination of hardware and software means, e.g. an ASIC and an FPGA, or at least one microprocessor and at least one memory with software modules located therein. The method embodiments described herein could be implemented partly in hardware and partly in software. Alternatively, the invention may be implemented on different hardware devices, e.g. using a plurality of CPUs.
[0043] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments and examples, those skilled in the art will recognize that the embodiments and examples disclosed herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
, Claims:We claim:
1. A system (300) for detecting a gas leakage of at least one of a refrigerant and a coolant in a vehicle, wherein the system (300) comprises:
a processor (211), wherein the processor (211) is coupled with a memory and wherein the processor (211) is configured to:
determine a third value of pressure from a first value of pressure and a second value of pressure, wherein the first value of pressure is measured by a first pressure sensor (112) and the second value of pressure is measured by a second pressure sensor (114);
compare the third value of pressure with a fourth value of pressure; wherein the fourth value of pressure is a fractional value of a threshold pressure value; and
perform, at least one of raising an alarm and turning the vehicle ON and OFF according to the result of comparison of the third value of pressure with the fourth value of pressure.
2. The system as claimed in claim 1, wherein the threshold value of the pressure is a function of a temperature value received from an ambient air temperature sensor (204) and a sun load value received from a sun load sensor (202) in the vehicle.
3. The system as claimed in claim 1, wherein the threshold value of the pressure depends on a type of vehicle and varies according to a size and an architecture of the vehicle.
4. The system as claimed in claim 1, wherein the third value of pressure is an average of the first pressure value and the second pressure value in a refrigerant line of the vehicle.
5. The system as claimed in claim 1, wherein the first pressure sensor is connected in series with a suction line connecting an evaporator and a compressor in the vehicle; and the second pressure sensor is connected in series with a discharge line connecting the compressor and a condenser in the vehicle.
6. The system as claimed in claim 1, wherein the processor is configured to turn on the ignition of the vehicle when the first value of pressure is determined as higher than a first fractional value of the threshold pressure value.
7. The system as claimed in claim 1, wherein the processor is configured to raise an alarm with a low refrigerant indication; and turn the ignition of the vehicle ON when the first value of pressure is determined to be lower than a first fractional value of the threshold pressure value.
8. The system as claimed in claim 1, wherein the processor is configured to raise an alarm with an unsafe to drive indication and turn the ignition of the vehicle ON when the first value of pressure is detected to be lower than a second fractional value of the threshold pressure value.
9. The system as claimed in claim 8, wherein the processor is configured to keep the ignition of the vehicle OFF when the first value of pressure is lower than a third fractional value of the threshold pressure value.
10. A method for detecting a gas leakage of at least one of a refrigerant and a coolant in a vehicle, wherein the method comprising steps of:
determining a third value of pressure from a first value of pressure and a second value of pressure, wherein the first value of pressure is measured by a first pressure sensor (112) and the second value of pressure is measured by a second pressure sensor (114);
comparing the third value of pressure with a fourth value of pressure; wherein the fourth value of pressure is a fractional value of a threshold pressure value; and
performing at least one of raising and alarm and turning the vehicle ON and OFF according to the result of comparison of the third value of pressure with the fourth value of pressure.
11. The method as claimed in claim 10, wherein the threshold value of the pressure is a function of a temperature value received from an ambient air temperature sensor (204) and a sun load value received from a sun load sensor (202) in the vehicle.
12. The method as claimed in claim 10, wherein the threshold value of the pressure depends on a type of vehicle and varies according to a size and an architecture of the vehicle.
13. The method as claimed in claim 10, wherein the third value of pressure is an average of the first pressure value and the second pressure value in a refrigerant line of the vehicle.
14. The method as claimed in claim 10, the method comprises:
turning the ignition of the vehicle ON when the first value of pressure is determined as higher than a first fractional value of the threshold pressure value.
15. The method as claimed in claim 10, the method comprises:
raising an alarm with a low refrigerant indication; and turning the ignition of the vehicle ON when the first value of pressure is determined to be lower than a first fractional value of the threshold pressure value.
16. The method as claimed in claim 10, the method comprises:
raising an alarm with an unsafe to drive indication and turning the ignition of the vehicle ON when the first value of pressure is detected to be lower than a second fractional value of the threshold pressure value.
17. The method as claimed in claim 16, the method comprises:
keeping the ignition of the vehicle OFF when the first value of pressure is lower than a third fractional value of the threshold pressure value.