Systems and methods for transport climate control circuit management and isolation

A method of controlling a transport climate control system includes detecting for leaking of working fluid from a climate control circuit. The method also includes isolating a high-pressure side of the climate control circuit when leaking of the working fluid is detected. A method of controlling a transport climate control circuit includes detecting for overcharge and/or an undercharge of the climate control circuit. A transport climate control system includes a climate control circuit and a climate controller that is configured to detect for working fluid leaking from the climate control circuit. The climate controller configured to isolate a high-pressure side of the climate control circuit when leaking of the working fluid is detected.

FIELD

This disclosure generally relates to transport climate control systems. More specifically, this disclosure relates to detecting and minimizing leakage from a climate control circuit of a transport climate control system and/or mitigating overcharge or undercharge of the climate control circuit.

BACKGROUND

A transport climate control system is generally used to control environmental condition(s) (e.g., temperature, humidity, air quality, and the like) within a climate controlled space of a transport unit (e.g., a truck, trailer, a container (such as a container on a flat car, an intermodal container, etc.), a box car, a semi-tractor, a bus, or other similar transport unit). The transport climate control system can include, for example, a transport refrigeration system (TRS) and/or a heating, ventilation and air conditioning (HVAC) system. The TRS can control environmental condition(s) within the climate controlled space to maintain cargo (e.g., produce, frozen foods, pharmaceuticals, etc.). The HVAC system can control environmental conditions(s) within the climate controlled space to provide passenger comfort for passengers travelling in the transport unit. In some transport units, the transport climate control system can be installed externally (e.g., on a rooftop of the transport unit, under the transport unit, on a front wall of the transport unit, etc.).

The transport climate control system can include a climate control circuit with a compressor, a condenser, an expansion valve, and an evaporator. A working fluid can include a refrigerant that can be compressed and expanded as it flows through the climate control circuit and can be used to heat and/or cool the particular space.

SUMMARY

The embodiments described herein are generally directed to detecting and minimizing leakage from a climate control circuit in a transport climate control system (“TCCS”) and/or mitigating overcharge or undercharge of the climate control circuit.

Transport units can have a climate controlled space for cargo or passengers that is provided climate control (e.g., heated, cooled, etc.) by a climate control circuit of a transport climate control system. The climate control circuit can utilize a working fluid. The working fluid can include a flammable refrigerant. In some instances, the flammable refrigerant can leak from the climate control circuit into the climate controlled space. The climate control circuit can contain an amount of refrigerant that is sufficient to make the climate controlled space flammable. Minimization of the amount of leakage from the climate controlled circuit may be desirable to prevent the climate controlled space from becoming a flammable environment.

Disclosed embodiments are capable of operating a TCCS to minimize potential leakage of the working fluid into a climate controlled space. Disclosed embodiments can isolate a high-pressure side of the climate control circuit to mitigate the potential of working fluid leaking into the climate controlled space. The disclosed embodiments can, for example, close an electronic expansion and isolation valve (EEIV) and shutdown a compressor to isolate the high-pressure side. Some disclosed embodiments can detect an overcharge or undercharge of the climate controlled circuit based on the performance of the EEIV.

In an embodiment, a method is directed to controlling a TCCS for a transport unit. The TCCS includes a climate control circuit with a compressor and an electronic expansion and isolation valve (EEIV). The method includes operating the climate control circuit to condition a climate controlled space of the transport unit. Operating the climate control circuit to condition the climate controlled space includes compressing a working fluid with the compressor and expanding the working fluid with the EEIV. The method also includes detecting for leaking of the working fluid from the climate control circuit and isolating the high-pressure side of the climate control circuit when detected that the working fluid is leaking from the climate control circuit.

In an embodiment, the method also includes isolating a portion of the low-pressure side of the climate control circuit when the leaking of the working fluid is detected. In an embodiment, the climate control circuit includes an evaporator that heats the working fluid. The portion of the low-pressure side extends through an evaporator unit that contains the evaporator.

In an embodiment, the climate control circuit includes an isolation valve that is downstream of the evaporator and upstream of the compressor in the climate control circuit. The portion of the low-pressure side of the climate controlled circuit is isolated by at least closing an isolation valve.

In an embodiment, the isolating of the high-pressure side of the climate control circuit isolates the high-pressure side from the low-pressure side of the climate control circuit.

In an embodiment, isolating the high-pressure side of the climate control circuit includes closing the EEIV and shutting down the compressor.

In an embodiment, the method includes detecting, via a step position sensor, a step position of a stepper motor of the EEIV, and detecting at least one step position of the EEIV and one or more other operational parameters of the climate control circuit. The method also includes comparing operation of the EEIV to an expected operation of the EEIV, the expected operation of the EEIV being operation of the EEIV expected from the detected at least one step position of the EEIV and the detected one or more other operational parameters of the climate control circuit.

In an embodiment, the method includes determining a subcooling of the compressed working fluid. The subcooling is determined based on a detected pressure and temperature of the compressed working fluid position of the EEIV. The method determines that the climate control circuit is overcharged when the subcooling is greater than a predetermined threshold.

In an embodiment, the climate control circuit includes an electronic check valve that is downstream of the evaporator and upstream of the compressor in the climate control circuit. The method includes determining a location of a leak in the climate control circuit based on a valve positon of an electronic check valve.

In an embodiment, a method is directed to controlling a TCCS for a transport unit. The TCCS includes a climate control circuit with a compressor to compress a working fluid and an electronic expansion and isolation valve (EEIV) to expand the working fluid. The method includes detecting for overcharge of the climate controlled circuit.

The method includes a subcooling of the compressed working fluid. The subcooling is determined based on a detected pressure and temperature of the compressed working fluid. The method determines that the climate control circuit is overcharged when the subcooling is greater than a predetermined threshold.

In an embodiment, the detected temperature of the compressed working fluid is detected via a temperature sensor of the EEIV.

In an embodiment, a TCCS for a transport unit includes a climate control circuit and a climate controller. The climate control circuit includes a compressor, a condenser, an EEIV, and an evaporator for a working fluid. The compressor compresses the working fluid, the condenser cools the compressed working fluid, the EEIV expands the cooled working fluid, and the evaporator heats the expanded working fluid.

The climate controller detects for leaking of the working fluid from the climate control circuit. The climate controller isolates a high-pressure side of the climate control circuit when leaking of the working fluid is detected.

In an embodiment, the climate controller at least closes the EEIV and shuts down the compressor to isolate the high-pressure side of the climate control circuit.

In an embodiment, the EEIV includes a stepper motor and a step position sensor. The step position sensor is for detecting a step position of the stepper motor. The climate controller detects, via the step position sensor, the step position of the stepper motor. The climate controller compares operation of the EEIV to an expected operation of the EEIV to determine whether working fluid is leaking. The expected operation of the EEIV being operation of the EEIV expected from at least one detected step position and one or more other detected operational parameters of the climate control circuit.

In an embodiment, the climate control circuit includes an isolation valve downstream of the evaporator and upstream of the compressor. When leaking of the working fluid is detected, the climate controller isolates a portion of a low-pressure side of the compressor by closing the isolation valve.

In an embodiment, the climate control circuit includes an electronic check valve with a proximity sensor. The climate controller detects, via the proximity sensor, a valve position of the electronic check valve. The climate controller also determines a location of a leak in the climate control circuit based on the detected valve position of the electronic check valve.

Like reference characters refer to similar features.

DETAILED DESCRIPTION

The embodiments described herein are generally directed to detecting and minimizing leakage from a climate control circuit in a transport climate control system (“TCCS”) and/or detecting overcharging or undercharging of the climate control circuit.

In the following detailed description, reference is made to the accompanying drawings, which illustrate embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice what is claimed, and it is to be understood that other embodiments may be utilized without departing form the spirit and the scope of the claims. The following detailed description and the accompanying drawings, therefore, are not to be taken in a finite sense.

Different types of goods/cargo may need to be stored at specific environmental condition(s) while being stored within a transport unit. For example, perishable goods may need to be stored within a specific temperature range to prevent spoilage and liquid goods may need to be kept at a temperature above their freezing point. Also, goods having electronic components may need to be kept in environmental conditions with a lower moisture content to avoid damage to their electronic components. Passengers traveling in the transport unit may need to be kept in a climate controlled space with specific environmental condition(s) to ensure their comfort while traveling. For example, the climate controlled space containing the passengers should be at a temperature that is generally comfortable for passengers. A transport climate control system may blow conditioned air into the climate controlled space of the transport unit to keep the air within the climate controlled space at the desired environmental conditions.

ASHRAE Standard 34 (e.g., ASHRAE 34-2019) provides guidelines for determining the safety classification of a refrigerant or a refrigerant blend. Generally nonflammable refrigerants or blends are classified as Class 1, while highly flammable refrigerants or blends are classified as Class 3. Lower toxicity refrigerants or blends are classified “A”, while higher toxicity refrigerants or blends are classified “B”. Previously, many A1 refrigerants (e.g., R22, R134a, R410A, R125A, etc.) have been used due to generally being safe and providing good performance. Presently, most to all of the A1 refrigerants currently being used have been found to have a high global warming potential (“GWP”) and therefore significantly contribute to global warming when leaked into the environment. A variety of refrigerant and refrigerant blends (e.g., R32, R1234yf, R1234ze(E), etc.) have a lower GWP while providing performance (e.g., capacity, temperature glide, operating pressures, etc.) comparable to current A1 refrigerants. However, many of these comparable refrigerants/refrigerant blends are mildly flammable (e.g., classified as A2L) and therefore have been avoided due the dangerous flammable environment they can create when leaked into an enclosed space.

The embodiments described herein are generally directed to detecting and minimizing leakage from a climate control circuit in a TCCS, and/or detecting overcharging or overcharging of the climate control circuit. The climate control circuit includes a compressor for compressing a working fluid and a EEIV for expanding the working fluid. The working fluid including a flammable refrigerant. The climate controlled circuit is configured to providing conditioning (e.g., heating, cooling, etc.) to a climate controlled space. The TCCS includes a climate controller for controlling the climate control circuit. For example, the climate controller is configured to isolate the high-pressure side of the climate control circuit when leaking of working fluid is detected. This can advantageously limit the flow of working fluid within the climate control circuit such that the amount of refrigerant that can leak into a climate controlled space is reduced/minimized.

FIG.1illustrates one embodiment of a climate controlled transport unit1attached to a tractor5. The climate controlled transport unit1includes a transport unit10and a transport climate control system (“TCCS”)20for the transport unit10. Dashed lines are used inFIG.1to illustrate features that would not be visible in the view shown. The transport unit10may be attached to the tractor5that is configured to tow the transport unit10to and from different locations. When not being transported, the transport unit10may be parked and unattached from the tractor5. It will be appreciated that the embodiments described herein are not limited to tractor and trailer units, but can apply to any type of transport unit such as a container (e.g., a container on a flat car, an intermodal container, etc.), a truck, a box car, a commercial passenger vehicle (e.g., school bus, railway car, subway car, etc.), or other similar transport unit.

The TCCS20includes a climate control unit (“CCU”)30that provides environmental control (e.g. temperature, humidity, air quality, etc.) within a climate controlled space12of the transport unit10. The climate controlled space12is an internal space of the transport unit10. The CCU30provides conditioned air into the climate controlled space12of the transport unit10to provide a desired conditioned environment for the goods being held within the climate controlled space12of the transport unit10. The desired conditioned environment for the climate controlled space12can have one or more desired environmental conditions (e.g., temperature, humidity, air quality, etc.). For example, the CCU30may provide cooled air to the climate controlled space12when perishable goods are being kept within the transport unit10. In another example, the CCU30may dehumidify the air within the climate controlled space12of the transport unit10when electronics are within the transport unit10. The CCU30includes a climate control circuit (e.g., seeFIG.2, seeFIG.3, etc.) for providing conditioned air to the climate controlled space12.

The CCU30is disposed on a front wall14of the transport unit10. In other embodiments, it will be appreciated that the CCU30can be disposed, for example, on a roof14or another wall of the transport unit10. The climate controlled transport unit1can include a battery (not shown), an internal combustion engine (not shown), or a both as a power source. The TCCS20may be a hybrid power system that uses a combination of battery power and engine power or an electric power system that does not include or rely upon an internal combustion engine of the TCCS20or the tractor5for power.

The TCCS20also includes a programmable climate controller40and one or more sensors50. The sensor(s)50are configured to measure one or more parameters of the climate controlled transport unit1(e.g., an ambient temperature and/or ambient humidity outside of the transport unit10, a compressor suction pressure, a compressor discharge pressure, a temperature of air supplied into the climate controlled space12by the CCU30, a temperature of air returning from the climate controlled space12to the CCU30, a humidity within the climate controlled space12, etc.) and communicate parameter data to the climate controller40. The climate controller40is configured to control operation of the TCCS20including components of the climate control circuit. The climate controller40may be a single integrated control unit42or a control unit formed by a distributed network of climate controller elements42,44. The number of distributed control elements in a given network can depend upon the particular application of the principles described herein.

FIG.2is a schematic diagram of an embodiment of a CCU100. The CCU100can be utilized in a TCCS (e.g., the TCCS10inFIG.1, etc.) to condition a climate controlled space102. The CCU100includes a climate control circuit130that is utilized to control environmental condition(s) (e.g., temperature, humidity, air quality, etc.) of the climate controlled space102. In an embodiment, the climate controlled space102is the climate controlled space of a transport unit (e.g., climate controlled space12of transport unit10inFIG.1, etc.). The CCU100includes an evaporator unit110and a condenser unit120.

The evaporator unit110includes an evaporator air inlet112, an evaporator air outlet114, and an internal volume116. Air passes through the evaporator unit110by entering through the evaporator air inlet112and exiting through the evaporator air outlet114. In particular, air from the climate controlled space102enters the evaporator unit110through the air inlet112, the air is conditioned within the evaporator unit110(e.g., heated, cooled, etc.), and the conditioned air is discharged from the evaporator unit110through the evaporator air outlet114. The conditioned air flows from the evaporator air outlet114to the climate controlled space102and conditions the climate controlled space102. The evaporator air inlet112can also be referred to as an air return inlet, and the evaporator air outlet114can also be referred to as a conditioned air outlet.

The condenser unit120includes an ambient air inlet122, an ambient air outlet124, and an internal volume126. Ambient air from the external environment104(e.g., ambient air from outside the climate controlled transport unit1inFIG.1, etc.) flows through the condenser unit120by entering through its ambient air inlet122and exiting through its ambient air outlet124.

InFIG.2, the evaporator unit110includes a damper118that regulates the flow rate of the conditioned air from the evaporator unit110. It will be appreciated that the evaporator unit110and the condenser unit120in various embodiments may each include one or more fan(s) and/or damper(s) to control the flow of respective air therethrough. For example, the evaporator unit110can include one or more evaporator blowers (not shown) that discharges conditioned air through the evaporator air outlet114and/or retrieves air from the climate controlled space104through the evaporator air inlet112. For example, the condenser unit120can include one or more condenser fans (not shown) that pushes air out of the condenser unit120through the ambient air outlet124.

The internal volume116of the evaporator unit110is separate from the internal volume126of the condenser unit120. For example, the CCU100can include a bulkhead105that separates the internal volume116of the evaporator unit110from the internal volume126of the condenser unit120. Accordingly, air and/or leaked refrigerant within the condenser unit120generally cannot flow into the evaporator unit110and therefore cannot flow into the conditioned space climate controlled space102(e.g., the internal volume116of the condenser unit120is not fluidly connected to the climate controlled space102).

As shown inFIG.2, the climate control circuit130includes components that are located in the evaporator unit110and components that are located in the condenser unit120, as discussed in more detail below. The climate control circuit130extends through the bulkhead105. The pipes, hoses, etc. of the climate control circuit130extend through the bulkhead105to pass the working fluid between the components of climate control circuit130in the evaporator unit110and the components of the component of the climate control circuit130in the condenser unit120.

The climate control circuit130includes a compressor132, a condenser134, an electronic expansion and isolation valve (EEIV)140, and an evaporator150. As shown inFIG.2, the climate control circuit130can also include a receiver tank152, an economizer154, a distributor156, and an accumulator tank158. In an embodiment, the climate control circuit130can be modified to include additional components, such as, for example, one or more additional valve(s), sensor(s), an overflow tank, a filter drier, or the like.

Operation of the climate control circuit130is controlled by a programmable climate controller180. The climate controller180is configured to detect various operating parameters of the climate control circuit130. For example, the climate controller uses one or more sensor(s) (e.g.; sensors50inFIG.1; proximity sensor162, step position sensor182, temperature sensor184, temperature sensor186, etc.) for detecting one or more operating parameters of the climate control circuit130. In an embodiment, the climate controller180is a climate controller of a transport climate controller system (e.g., the climate controller40of the TCCS20inFIG.1). In an embodiment, the climate controller180includes a memory (not shown) for storing information and a processor (not shown). The climate controller180is configured to control operation of the CCU100and its components. The climate controller180is shown inFIG.2as a single integrated control unit. However, it will be appreciated that the climate controller180in an embodiment may a single integrated control unit or a distributed network of climate controller elements (e.g., distributed network of climate controller elements42,44inFIG.1, etc.).

The components of the climate control circuit130are fluidly connected. Dashed lines are provided inFIGS.2-6to indicate optional features or locations. Dashed dotted lines are provided inFIGS.2and3to illustrate electronic communications between different components. For example, a dashed dotted line extends from the climate controller180to the compressor132as the climate controller180is configured to control the compressor132. Dotted arrows are provided inFIGS.2and3to indicate flows of air into and out of the evaporator unit110and the condenser unit120.

A working fluid flows through climate control circuit130. The working fluid can include one more flammable refrigerants. In an embodiment, the refrigerant of the working fluid includes one or more refrigerants that classify as A2L. For example, the refrigerant can be a single refrigerant or a refrigerant blend (e.g., a combination of two or more refrigerants) that classifies as A2L refrigerant. For example, the working fluid can include one or more of, but is not limited to, R32, R1234yf, R1234ze(E), and R454C. It should be noted that a working fluid can also include non-refrigerant components. For example, non-refrigerant components can be, but not limited to, lubricants, impurities, refrigeration system additives, tracers, ultraviolet dyes, and solubilizing agents. In general, these additional components are present in small concentrations relative to the refrigerant(s) in the working fluid.

In an embodiment, the climate control circuit130is configured to operate in a cooling mode to provide conditioned air (e.g., cooled air) to the ambient space102. Flow of the working fluid through the climate control circuit130in the cooling mode when operating normally (e.g., working fluid is not leaking, etc.) is described below. Generally, the main flow path in the climate control circuit130for the working fluid is from the compressor132to the condenser134, from the condenser134to the EEIV140, from the EEIV140to the evaporator150, and from the evaporator150to back to the compressor132.

Beginning at the compressor132, the compressor132includes a suction port133A and a discharge port133B. Working fluid in a lower pressure gaseous state or mostly gaseous state is suctioned into the compressor132via its suction port133A. The working fluid is compressed as it flows through the compressor132. Compressed working fluid is discharged from the compressor132via its discharge port133B and flows to the condenser134. The lower pressure working fluid flows into the suction port133A of the compressor132and the compressed higher pressure working fluid flows out from the discharge port133B of the compressor132.

The compressor132is a multispeed compressor. In other embodiments, the compressor132may be a single speed compressor. The compressor132can be driven by a prime mover (not shown). For example, the prime mover may be an internal combustion engine, an electrical drive motor, or a combination thereof. In some embodiments, the CCU100can include a combination of an internal combustion engine and an electric drive motor and can be configured to use the internal combustion engine alone or the electric drive motor alone. In some embodiments, the CCU100can include a combination of an internal combustion engine and an electric drive motor and can be configured to use a combination thereof (e.g., both operating at the about the same time to power the various components of the CCU100, etc.). In some embodiments, the CCU100may be an electrically powered system that relies upon one or more batteries that are recharged using a local power source (e.g., an internal combustion engine of the CCU100, an internal combustion engine of a tractor, etc.) and/or utility power.

The condenser134cools the compressed working fluid as it passes through the condenser134. As indicated by the dotted arrows inFIG.2, ambient air passes through the condenser unit120via its ambient air inlet122and its ambient air outlet124. The ambient air flows through the condenser134as it flows through the condenser unit120. The condenser134is a heat exchanger that allows the working fluid and the ambient air to be in a heat transfer relationship without physically mixing as they each flow through the condenser134. As the working fluid flows through the condenser134, the ambient air absorbs heat from the working fluid and cools the working fluid. The working fluid is cooled by the condenser134and becomes liquid or mostly liquid as it passes through the condenser134. In some embodiments, ambient air may not be used to directly cool the working fluid. For example, the ambient air may be used to cool an intermediate heat transfer fluid (e.g., a solution including water, glycol, etc.), and the cooled intermediate heat transfer fluid passes through the condenser134to the cool the working fluid.

The working fluid flows from the condenser134to the EEIV140. As shown inFIG.2, the liquid working fluid in this embodiment flows from the condenser134to the EEIV140by passing through the receiver tank152and an economizer154. The condenser134and the receiver tank152located in the condenser unit120, while the EEIV140and the economizer154are located in the evaporator unit110. The working fluid passing from the condenser unit120to the evaporator unit110as it flows from the condenser134to the EEIV140.

The EEIV140expands the cooled working fluid from the condenser134. The EEIV140allows the working fluid to expand as it flows through the EEIV140. The expansion causes the working fluid to decrease in temperature. For example, the expansion by the EEIV140drops the pressure of the working fluid by at or about 90% or greater than 90%. The expanded working fluid is in a two-phase gaseous/liquid phase. The expanded gaseous/liquid working fluid flows from the EEIV140to the evaporator150via the distributor156. The distributor156distributes the expanded working fluid into the evaporator150.

The EEIV140includes a valve housing142and a stepper motor144. The EEIV140is configured to be opened to various degrees (e.g., fully open, 75% open, 50% open, 25% open, etc.) and to be closed (e.g., has a closed position configured to entirely block the flow of working fluid through the EEIV140). The EEIV140is adjustable to different degrees of open to change the flow rate of the working fluid through the EEIV140. As discussed herein, it should be understood that “closed” means a valve is fully closed, and that “open” means the valve is in valve position other than fully closed (e.g., a fully open valve position, a 75% open valve position, in a 50% open valve position, in a 25% open valve position, etc.). The EEIV140is operated (e.g., adjusted to a specific valve positon) using the stepper motor144. The stepper motor144controls the valve position of the EEIV140. In an embodiment, the stepper motor144is coupled to a valve body146of the EEIV140and moves the valve body146relative to an orifice148of the EEIV140. For example, the EEIV140is closed by the stepper motor144moving the valve body146to a closed position that seals the orifice148.

During normal operation (e.g., when providing conditioning and no leakage of working fluid leak is detected), the climate controller180controls the stepper motor144to adjust the flowrate through the EEIV140. The number of steps for the stepper motor144may vary based on the configuration of climate controlled transport unit in a particular embodiment (e.g., the configuration of the CCU100, the climate control circuit130, and/or the climate controlled space102). The stepper motor144can have a number of steps that allows the stepper motor144to quickly close the EEIV140while still allowing precise control of the flow through EEIV140for precise control of the conditioning of the climate controlled space102. The stepper motor144may be configured to have, for example, 800 steps. For example, the first step (e.g., step one) and the last step (e.g., step800) can correspond to the EEIV140being closed and being fully open (e.g., 100% open), or vice-versa. In an embodiment, the stepper motor144can have a different number of steps than 800. The stepper motor144is also configured to be adjustable to each of its steps that are between its first step and its last step. The stepper motor144can allow the EEIV140to respond faster (e.g., close faster, open faster, etc.) than previous electronic expansion valves. The EEIV140also includes a step position sensor182for the stepper motor144. The step position sensor182can be used to detect the current step position SP of the stepper motor144(e.g., the current step of the stepper motor144). The step positon SP of the stepper motor144can correspond with the valve position of the EEIV140as the movement of the stepper motor144changes the valve position of the EEIV140. The climate controller180is configured to detect, via the step position sensor182, the step position SP of the stepper motor144. In an embodiment, the climate controller180uses the step position SP of the stepper motor144to detect the current valve position of the EEIV140(e.g., the degree that the EEIV140is open, if the EEIV140is closed), as the step position SP corresponds with the valve position of the EEIV140. Operation of the EEIV140is discussed in more detail below.

An “electronic” expansion valve is an expansion valve that is driven by an electronic motor to adjust the degree that the valve is open (e.g., to vary the amount of working fluid flowing through the expansion valve). In contrast, a “mechanical” expansion valve is driven by a mechanical fluid system in which variation in the superheat of the working fluid automatically adjusts the degree that the valve is open (e.g., a temperature sensing bulb in which variation in working fluid temperature automatically adjusts the degree that the valve is open). An “isolation” valve is a valve configured to seal closed to block fluid therethrough (e.g., a closed position in which the valve's office is sealed shut). For example, the EEIV140is both i) an “electronic expansion” valve as the EEIV140is configured to be adjustable by its electronic stepper motor144and ii) an “isolation” valve as the EEIV140is configured to have a closed position in which the EEIV140is sealed closed (e.g., the closed position in which its valve body146seals the orifice148, the EEIV140is 100% closed).

The evaporator150heats the working fluid as it passes through the evaporator150. As shown inFIG.2, the air to be conditioned (e.g., air from the climate controlled space102) flows through the evaporator unit110physically separate from the working fluid via the evaporator air inlet112and the evaporator air outlet114. The air passes through the evaporator150as it flows through the evaporator unit110. The evaporator150is a heat exchanger that allows the working fluid and the air to be in a heat transfer relationship without physically mixing as they each flow through the evaporator150. As the working fluid flows through the evaporator150, the working fluid absorbs heat from the air and cools the air. The working fluid is heated by the evaporator150and becomes gaseous or mostly gaseous as it passes through the evaporator150.

The heated working fluid flows from the evaporator150back to the compressor132. As shown inFIG.2, the gaseous/mostly gaseous working fluid in this embodiment flows from the evaporator150to the compressor132by passing through the economizer154, an electronic check valve160, and the accumulator tank158. The evaporator150and the economizer154are located while the evaporator unit110, while the compressor132and the accumulator tank158are located within the condenser unit120. The working fluid passing from the evaporator unit110to the condenser unit120as it flows from the evaporator150to the compressor132.

The compressor132receives lower pressure working fluid and discharges higher pressure compressed working fluid, while the EEIV140receives higher pressure working fluid and discharges expanded lower pressure working fluid. Accordingly, the climate control circuit130includes a high-pressure side170and a low-pressure side172. The high-pressure side170is a portion of the climate control circuit130that extends from the discharge port133B of the compressor132to the EEIV140and includes the condenser134. The high-pressure side170receives the higher pressure compressed working fluid discharged by the compressor132and supplies it to the EEIV140. The low-pressure side172is a portion of the climate control circuit130that extends from the EEIV140to the suction port133A of the compressor132and includes the evaporator150. The low-pressure side172receives lower pressure expanded working fluid from the EEIV140and supplies it to the compressor132.

As shown inFIG.2, the climate control circuit130also includes an electronic check valve160that is downstream of the evaporator150and upstream of the compressor132. The working fluid passes through the electronic check valve160as it flows from the evaporator150to the compressor132. The valve of the electronic check valve160is a conventional check valve that only allows the working fluid to flow through in a forward direction. The working fluid attempting to flow through the check valve in the reverse direction automatically moves its valve body into a closed position that seals the check valve and prevents working fluid from flowing through. The electronic check valve160automatically opens/closes based on fluid flow and is not driven by a motor, solenoid, etc. The electronic check valve160can prevent working fluid in the condenser unit120from flowing into the evaporator unit110.

InFIG.2, the electronic check valve160is located in the condenser unit120. In other embodiments, the climate control circuit130may include the electronic check valve160in a different location after the evaporator150and before the compressor132than shown inFIG.2. The electronic check valve160may be located in the evaporator unit110. In an embodiment, the electronic check valve160may be located in the evaporator unit110downstream of the evaporator150and the economizer154and upstream of the compressor132(e.g., the location A inFIG.2). In an embodiment, the electronic check valve160may be located in the evaporator unit110downstream of the evaporator150and upstream of the economizer154and the compressor132(e.g., the location B inFIG.2).

The electronic check valve160includes a proximity sensor162. The proximity sensor162is used to detect a valve position of the electronic check valve160(e.g., whether the electronic check valve160is open or closed). The proximity sensor162is attached to the outside of the electronic check valve162(e.g., attached to the outside of a valve housing of the electronic check valve160) or into the housing of the electronic check valve162without extending into the interior of the electronic check valve162(e.g., does not pass through the housing into passageway for the working fluid, does not require openings or holes that extend through the valve housing of the electronic check valve160, etc.). The proximity sensor162avoids adding any openings/holes into the electronic check valve160that are potential leakage paths for the working fluid. In an embodiment, the proximity sensor162is a magnetic field sensor attached to the outside of the electronic check valve160. The proximity sensor162measures a magnetic field of the electronic check valve160, which is different between the open position and the closed position of the electronic check valve160(e.g., the closed position results in a first magnetic field and the closed position results in second magnetic that is different from the first magnetic field). For example, the positon of the gate (not shown) within the electronic check valve160affects the magnetic field measured by the proximity sensor162. The climate controller180can be configured to detect, via the proximity sensor162, whether the electronic check valve160is open or closed.

During normal operation, the climate controller180is configured to control the EEIV140so that the working fluid heated by the evaporator150(e.g., the working fluid after the evaporator150and before the compressor132) has a desired amount of superheat. The superheat of a fluid is the difference between its current temperature and its dew point at its current pressure (e.g., T(Px)superheat=T(Px)Current−T(Px)Saturation temperature). The desired amount of the superheat can vary based on the configuration of a particular CCU and/or a climate control circuit. For example, the predetermined amount of superheat can be selected to minimize superheat while ensuring the working fluid retains sufficient superheat when entering the compressor132(e.g., enough superheat to prevent significant condensation of the refrigerant in working fluid before or within the compressor132). Generally, the efficiency of the CCU100decreases as the amount of superheat is increased while significant condensation of the refrigerant can damage the compressor132.

The saturation temperature of the working fluid at operating pressure(s) of the climate control circuit130can be known from, for example, previous testing of the working fluid and/or its components (e.g., testing of its refrigerant(s), etc.). Therefore, the predetermined amount of superheat can correspond to a (predetermined) target temperature/temperature range for the heated working fluid (e.g., T(Px)Target=Tsuperheat+T(Px)Saturation Temperature). For example, the target temperature or temperature range, the predetermined amount of superheat, and/or the saturation temperature(s) for the working fluid can be stored in the memory of the climate controller180. The climate control180is configured to operate the climate control circuit180so that the working fluid after being heated by the evaporator150is at the target temperature or within the target temperature range.

In an embodiment, the pressures in the climate control circuit130vary based on its operation (e.g., the discharge pressure of a multispeed compressor can vary with its speed, etc.). To maintain the predetermined amount of superheat, the target temperature/temperature range can be determined based on a detected evaporator outlet pressure of the working fluid (e.g., the current pressure of the heated working fluid). The climate controller180can be configured to detect the pressure of the heated working fluid directly (e.g., with a pressure sensor) or indirectly (e.g., based on current speed of the compressor132, based on current electrical power being provided to an electric motor for the compressor132, based on a discharge pressure of the compressor132, etc.). For example, the climate control circuit130can include a pressure sensor188that measures a pressure P1of the working fluid after passing through evaporator150. The pressure sensor188is located downstream of the evaporator150and upstream of the compressor132. As show inFIG.2, the pressure sensor188is located at or near the inlet of the compressor132and measures a pressure P1at the suction inlet of the compressor132. The pressure sensor188can also be referred to as a suction pressure sensor. In an embodiment, the pressure sensor188may be located closer to the outlet of the evaporator150. For example, the pressure sensor188can be located at the outlet of the evaporator150or between the evaporator150and the economizer154in the climate control circuit130.

The climate controller180can be configured to detect one or more of the evaporator inlet temperature, the evaporator outlet temperature (e.g., heated working fluid temperature T1), compressor discharge pressure (e.g., compressed working fluid pressure P1), evaporator pressure (e.g., heated working fluid pressure/suction pressure P1), and the step position SP of the stepper motor144. In an embodiment, the climate controller180can be configured to detect for leaking working fluid, an overcharge of the climate control circuit130, and/or an undercharge of the climate controller circuit130based on one or more of these detected parameters of the climate control circuit130.

As shown inFIG.2, the climate control circuit130includes a temperature sensor184located after the evaporator150and before the compressor132. The temperature sensor184can be used to detect a temperature T1of the working fluid after being heated by the evaporator150. For example, the temperature sensor184can be configured to detect the temperature T1of the working fluid discharged from the evaporator150. The climate controller180can detect the temperature T1of the heated working fluid using the temperature sensor184. The climate controller180is configured to control the EEIV140so that the temperature T1of the heated working fluid is at the target temperature (or temperature range). As discussed above, the target temperature or temperature range can vary with the pressure of the heated working fluid. In an embodiment, the climate control circuit130is configured to detect a pressure of the heated working fluid indirectly (e.g., based on electrical current supplied to the compressor132, discharge pressure of the compressor132, etc.) or directly (e.g., via a pressure sensor).

A climate control circuit is configured to utilize a specific amount of working fluid (e.g., has a designed working fluid capacity). The capacity of a climate control circuit varies based on its particular configuration (e.g., the sizing of the components in the climate control circuit, etc.). An operator and/or technician may fill a climate control circuit with more working fluid than its designed capacity, which can be referred to as overcharging. An operator and/or technician may fill a climate control circuit with less working fluid than its designed capacity, which can be referred to as undercharging. As shown inFIG.2, the EEIV140can include a temperature sensor186. The temperature sensor186is on the high-pressure side172of the EEIV140(e.g., located before the orifice148, etc.). The temperature sensor186measures a temperature T2of the unexpanded compressed working fluid in the EEIV140. The temperature T2of the unexpanded working fluid is the temperature of the compressed working fluid after being discharged from the compressor132(e.g., after the discharge port133B, etc.) and before being expanded by the EEIV140(e.g., before the orifice148, etc.). For example, the temperature sensor186measures a temperature T2of the unexpanded working fluid within the EEIV140. The climate controller180can detect the temperature T2of the unexpanded working fluid via the temperature sensor186.

As shown inFIG.2, the climate control circuit130can include a discharge pressure sensor189for measuring the pressure P2of the unexpanded working fluid. The discharge pressure189measures the pressure P2of the compressed working fluid in the high-pressure side172of the climate control circuit130. The pressure P2of the unexpanded working fluid is the pressure of the compressed working fluid after being compressed by the compressor132and before being expanded by the EEIV140. For example, the pressure sensor189is provided downstream of the compressor132and upstream of the EEIV140in the climate control circuit130. The climate controller180can detect the pressure P2of the unexpanded working fluid via the pressure sensor189.

In an embodiment, the climate controller180is configured to detect overcharging of the climate control circuit130based on subcooling of the compressed working fluid. Subcooling is the difference between the saturation temperature (“TSAT”) and the actual temperature T2of the unexpanded working fluid (e.g., subcooling=TSAT−T2). As discussed above, the saturation temperature of a fluid is based on its pressure (e.g., TSATis determined based on the detected pressure P2). The climate controller180can determine the subcooling of the unexpanded working fluid based on the pressure P2and the temperature T2of the unexpanded working fluid. The climate controller180determines that the climate control circuit130is overcharged when the subcooling is greater than a predetermined threshold. In an embodiment, the subcooling is detected for the compressed working fluid after being compressed by the compressor and before being expanded by the EEIV.

In an embodiment, the climate controller180is configured to detect undercharging of the climate control circuit130based on operation of the EEIV140. For example, the climate controller180may determine that the climate control circuit130is undercharged based on comparing an expected step position of the EEIV140to an actual step positon SP. An undercharge may be detected when the variance between the expected step positon and the actual step position for the EEIV140is greater than a predetermined threshold. For example, the climate controller180may determine that the climate control circuit130is undercharged based on comparing the temperature of the working fluid heated by the evaporator to an expected temperature of said working fluid. An undercharge may be detected when the variance between the expected temperature of and the actual temperature of the heated working fluid is greater than a predetermined threshold. Such comparisons are discussed in more detail below. In such embodiments, the climate controller180may determine that the climate control circuit130is undercharged (instead of leaking) based on whether a trend in the variance exceeds a predetermined limit.

As discussed above, leaking of the working fluid is potentially dangerous due to the flammability of its refrigerant. In particular, leaking of the refrigerant into the climate controlled space can be dangerous as it can cause the climate controlled space to become a flammable environment (e.g., an environment in which an ignition source causes flame propagation/an explosion). An ignition source (e.g., spark, flame, etc.) does not cause a propagating flame/explosion until a refrigerant concentration reaches its reaches a minimum concentration, which is known as a lower flammability limit.

The climate controller180is configured to isolate the high-pressure side170of the climate control circuit when the leaking of working fluid is detected. When working fluid is leaking from the climate control circuit130, the climate controller180is configured to at least shutdown the compressor132and close the EEIV140. The EEIV140is closed by the stepper motor144adjusting the EEIV140to its closed position. The compressor132when shutdown is configured to block working fluid from flowing through the compressor132(e.g., configured so that working fluid cannot flow through the shutdown compressor132). The isolation is configured to block the working fluid in the high-pressure170side from flowing to the low-pressure side172by at least the closed EEIV140and the shutdown compressor132. The isolation prevents the working fluid from flowing from the high-pressure side170to the low-pressure side130of the climate controller circuit130. For example, if a leak occurs in the evaporator150, the isolation limits the amount of refrigerant/working fluid that can leak through the evaporator150by preventing the working fluid in the high pressure side170from flowing to the evaporator150. The isolation of the climate control circuit130helps limit the potential leakage of working fluid into the condenser unit120, and therefore limits the amount of working fluid that can leak into the climate controlled space102and cause it to become a flammable environment.

In some embodiments, the climate control circuit130may have additional fluid connection(s) that fluidly connect the high-pressure side170and the low pressure side170(e.g., a hot gas bypass, etc.). In such an embodiment, isolating the high-pressure side170can include the climate controller180operating additional component(s) of the climate control circuit130(e.g., valves, etc.) in the additional fluid connection(s) to block each additional fluid connection. In an embodiment, the climate controller180can be configured to maintain the isolation of the high-pressure side (e.g., preventing a startup of the shutdown compressor132, keeping the EEIV140closed, etc.) until receiving instructions that the leakage is repaired. An operator and/or technician may instruct the climate controller180that the leak is repaired via, for example, a HMI190and/or a telematics unit192connected to the climate controller180.

In an embodiment, the climate controller180can also be configured to detect a location of a leak in the climate control circuit130. After isolating the high-pressure side170, the climate controller180detects a valve position of the electronic check valve160using the proximity sensor162. If the electronic check valve160is open, the leak can be determined to be in the low-pressure side172of the climate circuit130downstream of the electronic check valve160. For such a leak, the open electronic check valve160can allow working fluid in the low-pressure side172upstream of the electronic check valve160(e.g., working fluid within the evaporator150, etc.) to flow and leak into the internal volume126of the condenser unit120, where it can escape to and be safely dissipated into the external environment104. If the electronic check valve160is closed, the leak can be either in the high-pressure side170of the climate control circuit130or between the EEIV140and the electronic check valve160(e.g., in the evaporator150). For such a leak, the closed electronic check valve160prevents working fluid that is between the electronic check valve160and the compressor132(e.g., working fluid in the accumulator tank158) from flowing and leaking into the condenser unit120, where the leaked working fluid will flow into the climate controlled space102.

As shown inFIG.2, the climate controller180can be connected to the HMI190and the telematics unit192. The HMI190allows the climate controller130to display a warning to an operator of the climate controlled transport unit (e.g., climate controlled transport unit1) of the CCU100. In an embodiment, the CCU100includes the HMI190. In an embodiment, a vehicle for moving transport unit of the TCCS (e.g., the tractor5inFIG.1, etc.) includes the HMI190. The telematics unit192allows the climate controller130to wirelessly communicate a warning to a remote device (not shown) (e.g., a computer, a server, a server network, etc.). In an embodiment, the TCCS may include the telematics unit192. In an embodiment, a vehicle for moving transport unit of the TCCS (e.g., tractor5inFIG.1, etc.) includes the telematics unit192.

FIG.3is a schematic diagram of a CCU200, according to another embodiment. The CCU200can be utilized in a transport climate control system (e.g., the transport climate control system10inFIG.1, etc.) to condition a climate controlled space202. The CCU200includes a climate control circuit230that can be utilized to control an environmental condition (e.g., temperature, humidity, air quality, etc.) of the climate controlled space202. In an embodiment, the climate controlled space202is the climate controlled space of a transport unit (e.g., climate controlled space12of transport unit10inFIG.1, etc.).

The CCU200inFIG.3has a similar configuration to the CCU100inFIG.2, except for an isolation valve260being provided between the evaporator250and the compressor232instead of an electronic check valve. For example, the CCU200includes an evaporator unit210, a condenser unit220, and a climate control circuit230controlled by a climate controller280. For example, the CCU200includes the compressor232, a condenser234, an EEIV240with a stepper motor244, the evaporator250, a receiver tank252, an economizer254, a distributor256, and an accumulator tank258. The climate controller280may also be connected to an HMI290and a telematics unit292similar to the climate controller180. It will be appreciated that the CCU200inFIG.3in other embodiments may be modified in a similar manner as discussed above with respect to the CCU100inFIG.2.

A working fluid flows through the climate controlled circuit230and is used to condition air supplied to the climate controlled space202. In an embodiment, the working fluid includes flammable refrigerant as similarly discussed above for the working fluid of the climate control circuit130inFIG.2. As similarly discussed above regarding the CCU100inFIG.2, the climate controller280is configured to isolate the high-pressure side270of the climate control circuit230when it detects that working fluid is leaking.

As shown inFIG.3, the climate control circuit includes the isolation valve260that is disposed downstream of the evaporator250and upstream of compressor232in the climate control circuit230. The working fluid passes through the isolation valve260as it flows from the evaporator250to the compressor232. InFIG.3, the isolation valve260is provided in the condenser unit220. In other embodiments, the climate control circuit260may include the isolation valve260in a different location downstream of the evaporator250and upstream of the compressor232than shown inFIG.3. The isolation valve260may be located in the evaporator unit210. In an embodiment, the isolation valve260may be located in the evaporator unit210downstream of the evaporator250and the economizer256and upstream the compressor232(e.g., location A2inFIG.3, etc.). In an embodiment, the isolation valve260may be located in the evaporator unit210downstream of the evaporator250and upstream of the economizer252and the compressor232(e.g., location B2inFIG.3, etc.).

The climate controller280controls the isolation valve260. The isolation valve260has an open position and a closed position. In the closed position, the working fluid is blocked from flowing through the isolation valve160. In an embodiment, the isolation valve260has an on/off configuration with two valve positions of fully open and closed. In contrast to a check valve that opens/closes automatically by the pressure of the working fluid, an isolation valve is activated by an external force. For example, the isolation valve260is activated by supplying air, hydraulics, electrical current, etc. to the isolation valve260. The isolation valve260switches positions when activated (e.g., moves from its closed position to its open position, moves from its closed position to its open position). The isolation valve260can have a fail-close configuration in which the isolation valve260reverts to its closed position when not being activated. In an embodiment, the isolation valve260is a solenoid valve. For example, the climate controller280may supply electrical current to the isolation valve260to activate it.

In an embodiment, the isolation valve260includes a feedback sensor262. The feedback sensor262is connected to the climate controller260and provides a confirmation regarding the operation of the isolation valve260. The confirmation can be an electrical signal. The feedback sensor262is configured to send a confirmation that the isolation valve260is in its closed position. For example, the climate controller130switches the isolation valve260to its closed position when a leak is detected. Once the isolation valve260moves to its closed position, the feedback sensor262sends the confirmation to the climate controller280. The feedback sensor262ensures that the isolation valve260closes correctly to block flow of working fluid.

The climate controller280is configured to isolate a portion272A of the low-pressure side272of the climate circuit230when the working fluid is leaking. The portion272A of the climate circuit230extends from the EEIV240to the isolation valve260. The portion272A of the climate control circuit230includes the evaporator250. When working fluid leakage is detected, the climate controller280is configured to isolate the high-pressure side270and also close the isolation valve260, which isolates the portion272A of the low-pressure side272of the climate control circuit230. For example, the closed EEIV240and the closed isolation valve260isolate the portion272A of the low-pressure side272of the climate control circuit230.

When a working fluid leak is detected, the climate controller280is configured to isolate the climate circuit230into at least three different sections: the high-pressure side270, the first portion272A of the low-pressure side272, and a second portion272B of the low-pressure side272. The working fluid is prevented from flowing between the isolated sections. When a leak occurs in the climate control circuit230, the isolation prevents working fluid in other sections from flowing into the section with the leak. For example, if a leak occurs in the first portion272A of the low-pressure side272(e.g., in the evaporator250, etc.), the isolation prevents the working fluid within the high-pressure side270and the working fluid within the second portion272B of the low-pressure side272from flowing into the first portion272and through the leak into the evaporator unit210and then into the climate controlled space202. The isolation of the climate control circuit230helps limit the potential leakage of working fluid into the condenser unit210, and therefore limits the amount of working fluid that can leak into the climate controlled space202and cause it to become a flammable environment. The second portion272B extends from the isolation valve262to the compressor232. As shown inFIG.3, the second portion272B can include the accumulator tank258.

FIG.4is a flow chart for a method1000of controlling a TCCS that includes a climate control circuit. In an embodiment, the method1000may be employed by the TCCS20inFIG.1and as described above. In an embodiment, the method1000may be employed by the climate controller180inFIG.2to control a TCCS including the CCU100inFIG.2and as described above. The method1000starts at1010.

At1010, the TCCS operates a climate control circuit (e.g., climate control circuit130) to condition a climate controlled space (e.g., climate controlled space12, climate controlled space102). In an embodiment, the climate controlled space is the climate controlled space of a transport unit (e.g., climate controlled space12of transport unit10inFIG.1). The climate control circuit includes a compressor (e.g., compressor132), a condenser (e.g., condenser134), an EEIV (e.g., EEIV140), and an evaporator (e.g., evaporator150). The compressor compresses the working fluid, the condenser cools the working fluid, the EEIV expands the working fluid, and the evaporator heats the working fluid. For example, the climate controlled circuit operates in a cooling mode to supply conditioned air (e.g., cooled air, etc.) to the climate controlled space. The method1000then proceeds to1020.

At1020, the climate controller of the TCCS (e.g., climate controller180) detects whether working fluid is leaking from the climate control circuit. In an embodiment, the climate controller1020may detect that the working fluid is leaking based on one or more monitored parameters of the climate controlled transport unit (e.g., climate controlled transport unit1). The climate controller1020may utilize one or more sensors (e.g., temperature sensor, pressure sensor, air quality sensor, etc.) to monitor said parameter(s).

In some embodiments, detecting whether the working fluid is leaking1020can include comparing actual operation of an EEIV to an expected operation of the EEIV based on one or more step position(s) of the EEIV. The EEIV can include a stepper motor (e.g., stepper motor144) that adjusts the valve positon of the EEIV and a stepper position sensor (e.g., step position sensor182). The climate controller can be configured to detect, via the step position sensor, the step position of the stepper motor.

As discussed above, the climate controller can be configured to adjust the EEIV based on a superheat of the working fluid (e.g., to adjust the EEIV so that the temperature T1is at a target temperature/range, etc.). For example, leaking refrigerant results in the climate circuit having a lesser amount of working fluid. The lessor amount of working fluid in the climate control circuit can result in the EEIV having to be open larger to allow more working fluid therethrough and maintain the same amount of cooling by the evaporator. Specific relationship(s) between the other operating parameters and the step position of the EEIV in the climate control circuit with no leaks can be determined based on previous testing (e.g., of the climate control circuit, of a climate control circuit with the same or similar configuration, etc.). The climate controller can use these relationship(s) based on the step position(s) of the EEIV to detect if the working fluid is leaking.

In an embodiment, detecting whether the working fluid is leaking1020can include the climate controller comparing the step position of the EEIV to an expected step position1022. Comparing a step position to an expected step position1022can include the climate controller detecting operating conditions of climate control circuit, and comparing the step position(s) of the EEIV to expected step position(s) based on the operating conditions of the climate control circuit. For example, the climate controller is configured to detect step position(s) of EEIV (e.g., one or more step positions of the stepper motor of the EEIV) and temperature(s) of the working fluid (e.g., temperature T1of the heated working fluid, temperature T1of the working fluid over time, etc.) and pressure(s) of the working fluid (e.g., pressure P1of the working fluid, a discharge pressure of the compressor, pressure P1or discharge pressure of the compressor over time, etc.). In some embodiments, one or more of the operation conditions may have been detected in the operating of the climate control circuit at1010.

An expected step position can be the step position expected based on the temperature of the working fluid and the pressure of the working fluid used for determining the superheat of the working fluid (e.g., temperature T1, pressure P1, an operation parameter for indirectly detecting the pressure, etc.). The climate controller can be configured to determine that the working fluid is leaking when the variance between the actual step position of the EEIV (e.g., a detected step position) and the expected step position exceeds a predetermined threshold (e.g., a predetermined step amount, a predetermined numbers of steps, etc.). In an embodiment, the climate controller may be configured to determine that the working fluid is leaking at1022when a trend of said variance exceeds a predetermined limit (e.g., change in the variance is increasing by greater than X steps per minute, etc.). For example, the climate controller is configured to periodically determine the variance between the actual step position of the EEIV and an expected step position, and then determines a trend in the variance over a predetermined period (e.g., trend of the variance determinations over the previous X minutes/hours, etc.). The climate controller can then determine that working fluid is leaking at1022when the trend of the variance in the step position of the EEIV exceeds the predetermined limit. This can also be referred to as drift. In some embodiments, the trend in variance can be useful for determining whether the heat transfer circuit is undercharged or is leaking.

In an embodiment, detecting whether the working fluid is leaking1020can include comparing the temperature of the working fluid heated by the evaporator to an expected temperature of said working fluid1024. Comparing the temperature of heated working fluid to the expected temperature of the heated working fluid at1024can include detecting operating conditions of climate control circuit. For example, the climate controller is configured to detect a first step position of the EEIV, a second step positon of EEIV (e.g., the step position of the stepper motor of the EEIV), a first temperature of the heated working fluid (e.g., temperature T1of the heated working fluid at the first step positon), and a second temperature of the heated working fluid (e.g., temperature T1of the heated working fluid at the second step positon).

When the climate controller adjusts the EEIV to control the temperature of the heated working fluid (e.g., to control superheat, to control temperature T1, etc.), the climate controller is configured to compare how the adjustment of the EEIV affects the temperature of the heated working fluid to how it would be expected to affect the said temperature. For example, the climate controller can determine that the adjustment of the EEIV (e.g., from a detected first step position to a detected second step position, etc.) can be expected to increase or decrease the heated working fluid by X degrees (e.g., increase or decrease its superheat by X degrees, increase or decrease the temperature T1by X degrees). This temperature change is the expected temperature of the heated working fluid.

In an embodiment, the climate controller at1024can be configured to determine that a leak has occurred based on variance between the actual temperature of the working fluid (e.g., detected temperature T1) and the expected temperature of the working fluid. For example, when the variance is greater than a predetermined threshold (e.g., a predetermined temperature amount). In an embodiment, the climate controller may be configured to determine that the working fluid is leaking at1024when a trend of said variance exceeds a predetermined limit (e.g., change in the variance is increasing by greater than X degrees per minute, etc.). For example, the climate controller is configured to periodically determine the variance between the actual step position of the EEIV and an expected step position, and then determines a trend in the variance over a predetermined period (e.g., trend of the variance determinations over the previous X minutes/hours, etc.). The climate controller can then determine that working fluid is leaking at1024when the trend of the variance in the step position of the EEIV exceeds the predetermined limit. In some embodiments, the trend in variance can be useful for determining whether the heat transfer circuit is undercharged or is leaking. In some embodiments, the climate controller is configured to use an average of the variation or a time average of the detected temperature(s), pressure(s), etc.

In an embodiment, detecting whether the working fluid is leaking at1020may utilize different types of working fluid/refrigerant leak detection. For example, the climate controller may utilize a refrigerant detector (not shown) to detect if there is refrigerant in the climate controlled space and/or the internal space of the CCU (e.g., the internal space of the condenser unit, the internal space of the evaporator unit, etc.). The method1000then proceeds to1030. At1030, when leaking of the working fluid from the climate control circuit is detected, the method1000proceeds to1040. When leaking of the working fluid from the climate control circuit is detected, the method1000returns to1010. For example, the climate controller at1010continues the climate control circuit's conditioning of the climate controlled space when no working fluid leakage is detected.

At1040, the climate controller isolates the high-pressure side of the climate control circuit (e.g., high-pressure side170, high-pressure side270) when its detected that the working fluid is leaking. Isolating the high-pressure side can include shutting down the compressor at1042and closing the EEIV at1044. For example, the isolation of the high-pressure side at1040can prevent the working fluid in the high-pressure side from flowing into the low-pressure side of the climate control circuit (e.g., low-pressure side172, etc.). In an embodiment, the shutdown of the compressor at1042can occur prior to the closing of the EEIV at1044(e.g., prior to the EEIV reaching its closed position). The method1000then proceeds to1050. The method1000then proceeds to optional1050.

At1050, the climate controller determines a location of a leak in the climate control circuit. The climate control circuit can include an electronic check valve (e.g., electronic check valve160) with a proximity sensor (e.g., proximity sensor162). In an embodiment, determining a location of a leak in the climate control circuit1050can include detecting, via the proximity sensor162, the valve position of the electronic check valve1052. The valve position of the electronic check valve (e.g., open or closed) can indicate the location of the leak in the climate control circuit as discussed above with respect electronic check valve160in theFIG.2. The method the proceeds to optional1060.

At1060, the climate controller issues a warning that there is a working fluid leak. The warning may include the location of a leak as determined at1050. In an embodiment, issuing the warning1060can include an HMI (e.g., HMI190) connected to the climate controller displaying the warning to warn an operator of the climate controlled transport unit (e.g., climate controlled transport unit1). In an embodiment, issuing the warning1060can include a telematics unit (e.g., telematics unit192) connected to the climate controller wirelessly sending the warning to a remote device (e.g., a computer, a server, a server network, etc.).

In some embodiments, the method1000can include the climate controller maintaining the isolation at1040until receiving instructions that the leakage is repaired. For example, the climate controller can be configured to prevent a startup of the compressor until instructed that the leak is repaired. An operator and/or technician may instruct the climate controller that the leak is repaired via, for example, a HMI (e.g., HMI190) and/or a telematics unit (e.g., telematics unit192) connected to the TCCS. In such embodiments, the method1000would stay at1040,1050, or1060until receiving said instructions. After receiving instructions that the leakage has been repaired, method1000can proceed back to1010from1040,1050, or1060. For example, the climate controller can be configured to resume climate conditioning (e.g., startup the compressor, open the EEIV) once it receives instructions that the leak has been repaired.

FIG.5is a flow chart for a method1100of controlling a transport climate control system (TCCS) that includes a climate control circuit, according to another embodiment. In an embodiment, the method1110may be employed by the TCCS20inFIG.1and as described above. In an embodiment, the method1100may be employed by the climate controller280inFIG.2to control a TCCS that includes the CCU200inFIG.3and as described above. The method1100starts at1110.

The method1100is similar to the method1000inFIG.4, except for1150. For example, the method1100includes operating a climate controlled space to condition a climate controlled space at1110, determining whether the working fluid is leaking from the climate control circuit at1120, returning to1110or proceeding to1140based on whether the working fluid is leaking, isolating a high-pressure side of the climate control circuit at1140, and sending a warning at1160, similar to the method1000inFIG.4. After isolating a high-pressure side of the climate control at1140, the method1100can proceed from1140to optional1150.

At1150, the climate controller (e.g., climate controller280) isolates a portion of the low-pressure side (e.g., portion272A of low-pressure side272) of the climate control circuit (e.g., climate control circuit230). Isolating the portion of the low-pressure side of the climate control circuit1150can include closing an isolation valve1152(e.g., isolation valve260) in the climate control circuit. The isolation valve is located in the low-pressure side of the climate control circuit. For example, the isolation valve is located downstream of the evaporator (e.g., evaporator250) and upstream of the compressor (e.g., compressor232) in the climate control circuit. InFIG.5, isolating the portion of the low-pressure side1150occurs after closing the EEIV1142in1140. In an embodiment, isolating the portion of the low-pressure side1150may occur before or simultaneously with the closing of the EEIV1142and after the shutdown of the compressor1142. The method1100then proceeds to optional1160.

At1160, the climate controller issues a warning that there is a working fluid leak. In an embodiment, issuing the warning1160includes an HMI (e.g., HMI290) connected to the climate controller displaying the warning for warning an operator of the climate controlled transport unit (e.g., climate controlled transport unit1). In an embodiment, issuing the warning1160includes a telematics unit (e.g., telematics unit292) connected to the climate control wirelessly transmitting the warning to a remote device (e.g., a computer, a server, a server network, etc.).

In some embodiments, the method1100can include the climate controller maintaining the isolation at1140and1150until receiving instructions that the leakage is repaired. For example, the climate controller can be configured to prevent a startup of the compressor until instructed that the leak is repaired. An operator and/or technician may instruct the climate controller that the leak is repaired via, for example, a HMI (e.g., HMI190) and/or a telematics unit (e.g., telematics unit192) connected to the TCCS. In such embodiments, the method1100would stay at1150or1160until receiving said instructions. After receiving instructions that the leakage has been repaired, method1100can proceed back to1110from1150or1160. For example, the climate controller can be configured to resume climate conditioning (e.g., startup the compressor, open the EEIV, open the isolation valve, etc.) once it receives instructions that the leak has been repaired.

FIG.6is a flow chart for a method1200of controlling a transport climate control system (TCCS) that includes a climate control circuit, according to yet another embodiment. In an embodiment, the method1200may be employed by the TCCS20inFIG.1and as described above. In an embodiment, the method1200may be employed to control a TCCS that includes the CCU100inFIG.2and as described above or to control a TCCS that includes the CCU200inFIG.3and as described above. The method1200starts at1210.

At1210, a climate control circuit (e.g., climate control circuit130, climate control circuit230) is operated to condition a climate controlled space (e.g., climate controlled space12, climate controlled space102, climate controlled space202). In an embodiment, the climate controlled space is the climate controlled space of a transport unit (e.g., climate controlled space12of transport unit10inFIG.1, etc.). The climate control circuit includes a compressor (e.g., compressor132, the compressor232), a condenser (e.g., condenser134, condenser234), an EEIV (e.g., EEIV140, EEIV240), and an evaporator (e.g., evaporator150, evaporator250). The compressor compresses the working fluid, the condenser cools the working fluid, the EEIV expands the working fluid, and the evaporator heats the working fluid. For example, the climate controlled circuit operates in a cooling mode to supply conditioned air (e.g., cooled air) to the climate controlled space. The method1200then proceeds to1270and optionally proceeds to optional1220.

The method1200includes detecting whether working fluid is leaking from the climate control circuit at1220, which proceeds to determining whether the working fluid is leaking at1230, which proceeds to returning back to1210or to isolating a high-pressure side of the climate control circuit at1240.1220,1230, and1240inFIG.6are similar to1020,1030, and1040described inFIG.4. In an embodiment,1220,1230, and1240in the method1200have features similar to1020,1030, and1040of the method1000, respectively, as described above.

In an embodiment, the method1200may include determining a location of a leak in the climate control leak at1050and/or sending a warning at1060similar to the method1050of the method1000as shown inFIG.4and as described above. In an embodiment, the method1200may include isolating a portion of the low-pressure side of the climate control circuit at1150and/or sending a warning at1160of the method1100as shown inFIG.5and as described above. In some embodiments, the method1200can include the climate controller maintaining the isolation at1240until receiving instructions that the leakage as similarly discussed above for the method1000or as similarly discussed above for the method1100.

At1270, the climate control controller monitors for an overcharge or an undercharge of the climate control circuit. Monitoring for an overcharge or undercharge of the climate control circuit can include performing1272,1276,1278,1280and1282. At1272, the climate controller detects one or more operating parameters of the climate control circuit. Detecting the one or more parameters1272can include detecting a valve position of the EEIV1274, detecting the temperature (e.g., temperature T1, etc.) of the working fluid heated by the evaporator1275, and/or detecting a temperature (e.g., temperature T2, etc.) and pressure (e.g., pressure P2, etc.) of the unexpanded working fluid1276.

Detecting the valve position of the EEIV at1274can include the climate controller detecting, via a step position sensor (e.g., step position sensor182), a step position of the stepper motor (e.g., stepper motor144, stepper motor244) of the EEIV. Detecting the temperature of the working fluid heated by the evaporator at1275can include the climate controller detecting, via a temperature sensor (e.g., temperature sensor184), the temperature of the working fluid after being heated by the evaporator.

Detecting the temperature of the unexpanded working fluid at1276can include the climate controller detecting, via a temperature sensor (e.g., temperature sensor186), the temperature of the unexpanded working fluid. In an embodiment, climate controller detects the temperature of the unexpanded working fluid within the EEIV.

Detecting the pressure of the unexpanded working fluid at1276can include the climate controller detecting, via a pressure sensor (e.g., pressure sensor189), the pressure of the unexpanded working fluid. In an embodiment, detecting the temperature of the unexpanded working fluid may include the climate controller indirectly detecting the pressure of the unexpanded working fluid (e.g., based on current speed of the compressor, based on current electrical power being provided to an electric motor for the compressor, etc.). The method1200then proceeds to1278.

At1278, the climate controller determines a subcooling of the working fluid and/or expected operation of the EEIV. The subcooling at1278is the subcooling of the unexpanded working fluid (e.g., the compressed working fluid prior to being expanded by the EEIV) as similarly discussed above. The subcooling of the unexpanded working fluid can be used to determining if the climate control circuit is overcharged. For example, subcooling is the difference between the saturation temperature (“TSAT”) and the actual temperature T2of the unexpanded working fluid (e.g., subcooling=TSAT−T2). The climate controller180can determine the subcooling of the unexpanded working fluid based on the pressure P2and the temperature T2of the unexpanded working fluid. The method1200then proceeds to1280.

In an embodiment, determining the expected operation of the EEIV at1278can include determining an expected step position of the EEIV. For example, the climate controller can determine the expected step position in a similar manner as discussed above for the method1000. In another embodiment, determining the expected operation of the EEIV at1278can include an expected temperature of the working fluid after being heated by the evaporator. For example, the climate controller can determine the expected temperature of the heated working fluid in a similar manner as discussed above for the method1000

At1280A, the determined subcooling is compared to a predetermined threshold. The climate controller180can determine that the climate control circuit130is overcharged when the subcooling is greater than a predetermined threshold. When the subcooling does not exceed the predetermined threshold (e.g., the subcooling is equal to or less than the threshold), the method1200proceeds to1280B. When the subcooling exceeds the predetermined threshold, the method1200proceeds to1282.

At1280B, the expected operation of the EEIV is compared to the actual operation of the EEIV. In an embodiment, the climate controller can compare the expected step position of the EEIV to the actual step position of the EEIV (e.g., step position POS). In another embodiment, the climate controller can compare the expected temperature of the working fluid heated by the evaporator to the detected temperature of the working fluid heated by the evaporator (e.g., temperature T1). When the difference between the expected operation of the EEIV and the actual operation of the EEIV does not exceed a predetermined threshold (e.g., temperature amount, step amount, etc.), the method1200returns to1210. When the difference between the expected operation of the EEIV and the actual operation of the EEIV does exceed the predetermined threshold, the method1200proceeds to1282. At1282, the climate controller issues a warning that the climate control circuit is overcharged or overcharged. In an embodiment, issuing the warning at1280includes a HMI (e.g., HMI190, HMI290) connected to the climate controller displaying the warning to an operator of the climate controlled transport unit (e.g., climate controlled transport unit1). In an embodiment, issuing the warning1280includes a telematics unit (e.g., telematics unit192, telematics unit292) connected to the climate controller wirelessly communicating the warming to a remote device (e.g., a computer, a server, a server network, etc.).

The method1200inFIG.6has1280A and1280B as being subsequent steps. However,1280A and1280B may occur in a different order. In an embodiment, the order of1280A and1280B may be switched in the method1200. In another embodiment,1280A and1280B may occur in parallel in the method1200.FIG.6shows the method1200including both detecting for overcharge and undercharge of the climate control circuit. However, the method1200in some embodiments may include just one of detecting for an overcharge or detecting for an undercharge of the climate control circuit. In such an embodiment, the method1200can include just one of1280A or1280B.

In some embodiments, detecting for an overcharge or undercharge of the climate control circuit at1270may be combined with detecting whether working fluid is leaking fluid from the climate control circuit at1220. For example, detecting whether the working fluid is leaking from the climate control circuit at1220can include detecting a valve position of the EEIV (e.g., for comparing the step position of the EEIV to an expected step position at1022in the method1000, for comparing the temperature of the working fluid heated by the evaporator to an expected temperature of said working fluid at1024in the method1000). The climate controller can be configured to detect a valve position of the EEIV, and the detected valve positon may be used in both detecting whether working fluid is leaking from the climate control circuit at1220(e.g., for comparing the step position to, for comparing temperature of the heated working fluid, etc.) and in detecting for overcharging of the climate control circuit at1270(e.g., in determining a subcooling of the EEIV at1278). In an embodiment, the climate controller may be configured to shutdown the climate control circuit (e.g., shutdown the compressor, etc.) when it determines that there is an overcharge of the climate control circuit at1280B. For example, method1200may include shutting down the climate control circuit between1280B and1282, or after sending the warning at1282.

Aspects

Any of aspects 1-10 can be combined with any of aspects 11-20, and any of aspects 11-13 can be combined with aspects 14-20.

Aspect 1. A method of controlling a transport climate control system (TCCS) for a transport unit, the TCCS including a climate control circuit with a compressor and an electronic expansion and isolation valve (EEIV), the method comprising:

operating the climate control circuit to condition a climate controlled space of the transport unit, wherein operating the climate control circuit to condition the climate controlled space includes compressing a working fluid with the compressor and expanding the working fluid with the EEIV;

detecting for leaking of the working fluid from the climate control circuit; and

isolating a high-pressure side of the climate control circuit when detected that the working fluid is leaking from the climate control circuit.

Aspect 2. The method of aspect 1, wherein the high-pressure side of the climate control circuit is isolated from the low-pressure side of the climate control circuit.

Aspect 3. The method of either one of aspects 1 or 2, wherein isolating the high-pressure side of the climate control circuit includes closing the EEIV and shutting down the compressor.

Aspect 4. The method of any one of aspects 1-3, further comprising:

isolating a portion of a low-pressure side of the climate control circuit when detected that the working fluid is leaking from the climate control circuit.

Aspect 5. The method of aspect 4, wherein the climate control circuit includes an evaporator to heat the working fluid, the portion of the low-pressure side extending through an evaporator unit containing the evaporator.

Aspect 6. The method of either one aspects 4 or 5, wherein isolating the portion of the low-pressure side of the climate control circuit includes closing an isolation valve downstream of the evaporator and upstream of the compressor in the climate control circuit.
Aspect 7. The method of any one of aspect 1-6, wherein

expanding the working fluid in the EEIV includes a stepper motor adjusting the EEIV based on a superheat of the working fluid, and

detecting for leaking of the working fluid from the climate control circuit includes:

detecting at least one step position of the EEIV and one or more other operational parameters of the climate control circuit, and

comparing operation of the EEIV to an expected operation of the EEIV, the expected operation of the EEIV being operation of the EEIV expected from the detected at least one step position of the EEIV and the detected one or more other operational parameters of the climate control circuit.

Aspect 8. The method of any one of aspects 1-7, further comprising:

detecting for overcharge of the climate control circuit, wherein detecting for the overcharge of the climate control circuit includes:detecting a temperature and a pressure of the working fluid compressed by compressor,determining a subcooling of the working fluid compressed by the compressor based on the temperature and the pressure of the working fluid compressed by the compressor, anddetecting that the climate controlled circuit is overcharged when the subcooling is greater than a predetermined threshold.
Aspect 9. The method of aspect 8, wherein the EEIV includes a temperature sensor positioned on a low-pressure side of the EEIV, the detected temperature of the working fluid expanded by the EEIV being detected via the temperature sensor of the EEIV.
Aspect 10. The method of any one of aspects 1-3 and 7-9, further comprising:

determining a location of a leak in the climate control circuit when detected that the working fluid is leaking from the climate control circuit, wherein determining a location of the leak in the climate control circuit includes:detecting a valve position of an electronic check valve, the electronic check valve being downstream of the evaporator and upstream of the compressor in the climate control circuit, anddetermining a location of the leak in the climate control circuit based on the detected valve position of the electronic check valve.
Aspect 11. A method of controlling a transport climate control system (TCCS) for a transport unit, the TCCS including a climate control circuit with a compressor to compress a working fluid and an electronic expansion and isolation valve (EEIV) to expand the working fluid, the method comprising:

operating the climate control circuit to condition a climate controlled space;

detecting for at least one of overcharge and undercharge of the climate control circuit, wherein detecting for overcharge of the climate controlled circuit includes:detecting a temperature and a pressure of the compressed working fluid, anddetermining a subcooling of the compressed working fluid based on the temperature and the pressure of the compressed working fluid,

wherein detecting for an undercharge includes:detecting a step position of the EEIV, anddetermining an expected operation of the EEIV based on a step position of the EEIV; and

sending a warning when determined that the climate controlled circuit is at least one of overcharged or undercharged.

Aspect 12. The method of aspect 11, wherein the EEIV includes a temperature sensor, and the detected temperature of the working fluid after being compressed by the EEIV being detected via the temperature sensor of the EEIV.

Aspect 13. A transport climate control system (TCCS) for a transport unit, comprising:

a climate control circuit including:a compressor to compress a working fluid,a condenser to cool the working fluid compressed by the compressor,an electronic expansion and isolation valve (EEIV) to expand the working fluid condensed by the condenser, andan evaporator to heat the working fluid expanded by the EEIV; and

a climate controller configured to:detect for the working fluid leaking from the climate control circuit, andisolate a high-pressure side of the climate control circuit when determined that the working fluid is leaking from the climate control circuit.
Aspect 14. The TCCS of aspect 13, wherein the climate controller is configured to close the EEIV and shutdown the compressor, in order to isolate the high-pressure side of the climate control circuit.
Aspect 15. The TCCS of any one of aspects 13 and 14, wherein the EEIV includes a stepper motor and a step position sensor for detecting a step position of the stepper motor, and

the climate controller is configured to:detect, via the step position sensor, at least one step position of the stepper motor,detect one or more other operational parameters of the climate control circuit, andcomparing operation of the EEIV to an expected operation of the EEIV, the expected operation of the EEIV being operation of the EEIV expected from the detected at least one step position and the detected one or more other operational parameters of the climate control circuit.
Aspect 16. The TCCS of any one of aspects 13-15, wherein

the climate controller is configured to:detect a valve position of the EEIV and a temperature of the working fluid expanded by the EEIV,determine an expected temperature of the working fluid expanded by the EEIV based on the detected valve position of the EEIV,determine a subcooling of the EEIV by comparing the expected temperature of the working fluid expanded by the EEIV to the detected temperature of the working fluid expanded by the EEIV,determine that the climate control circuit is overcharged when the subcooling is greater than a predetermined threshold.
Aspect 17. The TCCS of any one of aspects 13-16, wherein

the climate control circuit includes an isolation valve downstream of the evaporator and upstream of the compressor, and

the climate controller is configured to isolate a portion of a low-pressure side of the compressor by closing the isolation valve when detected that the working fluid is leaking from the climate control circuit.

Aspect 18. The TCCS of aspect 17, further comprising:

a climate control unit including an evaporator unit and a condenser unit, the evaporator unit including the evaporator, and the condenser unit including the condenser, wherein

the portion of the low-pressure side extends through the evaporator unit.

Aspect 19. The TTCS of any one of aspects 13-16, wherein

the climate control circuit includes an electronic check valve with a proximity sensor, and

the climate controller configured to:detect, via the proximity sensor, a valve position of the electronic check valve, anddetermine a location of a leak in the climate control circuit based on the detected valve position of the electronic check valve.

The examples disclosed in this application are to be considered in all respects as illustrative and not limitative. The scope of the invention is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of this application.