Patent Description:
Refrigerated vehicles and trailers are commonly used to transport perishable goods. A transport refrigeration unit is commonly mounted to the vehicles or to the trailer in operative association with a cargo space defined within the vehicles or trailer for maintaining a controlled temperature environment within the cargo space.

Conventionally, transport refrigeration units used in connection with refrigerated vehicles and refrigerated trailers include a refrigerant compressor, a condenser with one or more associated condenser fans, an expansion device, and an evaporator with one or more associated evaporator fans, which are connected via appropriate refrigerant lines in a closed refrigerant flow circuit. Air or an air/gas mixture is drawn from the interior volume of the cargo space by means of the evaporator fan(s) associated with the evaporator, passed through the airside of the evaporator in heat exchange relationship with refrigerant whereby the refrigerant absorbs heat from the air, thereby cooling the air. The cooled air is then supplied back to the cargo space.

On many commercially available transport refrigeration units the compressor, and typically other components of the transport refrigeration unit, is powered during transit by a prime mover, either through a direct mechanical coupling or a belt drive. Alternatively, the transport refrigeration unit may be electrically powered (e.g., using an alternating (AC) synchronous generator that generates AC power). The generated AC power is typically used to power an electric motor for driving the refrigerant compressor, and other components of the transport refrigeration unit. In a different electrically powered transport refrigeration unit, the AC generator may be replaced with a battery pack to provide power to the loads. The battery pack is a finite source of power. Accordingly, additional methods of providing clean power for a transport refrigeration unit is desired.

<CIT> discloses a power system architecture configured to power a transport refrigeration system based on a determined AC power requirement. <CIT> discloses a trailer refrigeration system that incorporates a trailer refrigeration unit that is powered by multiple sources including a generator coupled to a truck, photovoltaic cells and a battery pack. <CIT> discloses a method for preserving autonomous operation of a transport climate control system including a controller determining whether a regulatory compliance at a current location is restricting and/or preventing the use of a prime mover for powering the transport climate control system while a transport unit is in transit. When the controller determines that use of the prime mover is being restricted or prevented because of a regulatory compliance, the method includes the controller instructing an auxiliary energy storage to provide power to the transport climate control system.

According to a first aspect of the invention, a transport refrigeration system is provided as recited in claim <NUM>.

Optionally, the one or more supplemental power sources only provide the supplemental electricity to the transport refrigeration unit during the condition of the transport refrigeration unit that requires supplemental electricity.

Optionally, the power management module is configured to command activation of the one or more supplemental power sources only during the condition of the transport refrigeration unit that requires supplemental electricity.

Optionally, the fuel cell also provides the electricity to the transport refrigeration unit during the condition of the transport refrigeration unit that requires supplemental electricity.

Optionally, the one or more supplemental power sources includes at least one of: an energy storage device configured to store electricity and provide electricity to the transport refrigeration unit; or an electric generation device configured to generate electricity and provide the electricity to the transport refrigeration unit.

Optionally, the one or more supplemental power sources includes an energy storage device configured to store electricity and provide electricity to the transport refrigeration unit.

Optionally, the energy storage device includes at least one of a battery system or a capacitor.

Optionally, the one or more supplemental power sources includes an electric generation device configured to generate electricity and provide the electricity to the transport refrigeration unit.

Optionally, the electric generation device includes at least one of an axle generator or a hub generator.

Optionally, the transport refrigeration system includes a thermal storage device configured to provide cooling for refrigerated cargo space of the transport container using a phase change material.

According to a second aspect of the invention, a method of operating a transport refrigeration system is provided as recited in claim <NUM>.

Optionally, the method may include activating of the one or more supplemental power sources only during the condition of the transport refrigeration unit that requires supplemental electricity.

Optionally, the method may include providing the electricity from the fuel cell to the transport refrigeration unit during the condition of the transport refrigeration unit that requires supplemental electricity; and powering the transport refrigeration unit using the supplemental electricity from the one or more supplemental power sources and the electricity from the fuel cell during the condition of the transport refrigeration unit that requires supplemental electricity.

Optionally, the energy storage device includes at least one of a battery system or a capacitor, or wherein the electric generation device includes at least one of an axle generator or a hub generator.

According to a third aspect of the invention, a computer program product tangibly embodied on a non-transitory computer readable medium is provided as recited in claim <NUM>.

The system of the first aspect of the invention may be configured to perform the method of the second aspect of the invention, and/or any features thereof. The method of the second aspect of the invention may comprise using and/or providing the system of the first aspect of the invention, and/or any features thereof. The computer program product of the third aspect of the invention may be adapted for use with the system of the first aspect of the invention, and/or may provide the method of the third aspect of the invention. The computer program product may comprise instructions that result in any of the features of the method of the second aspect of the invention.

Technical effects of embodiments of the present disclosure include powering a transport refrigeration unit with a fuel cell and providing supplemental electricity from one or more supplemental sources.

With reference to the accompanying drawings, which are provided by way of example only, like elements are numbered alike:.

Embodiments disclosed herein relate to powering a transport refrigeration unit with a fuel cell and providing supplemental electricity from one or more supplemental sources when the transport refrigeration unit may be in a condition that the fuel cell cannot handle on its own or a condition that can be more effectively and/or efficiently handled by supplementing the fuel cell's output.

Referring to <FIG> and <FIG>, various embodiments of the present invention are illustrated. <FIG> shows a schematic illustration of a transport refrigeration system <NUM>, according to an embodiment of the present disclosure. <FIG> shows an enlarged schematic illustration of the transport refrigeration system <NUM> of <FIG>, according to an embodiment of the present invention.

The transport refrigeration system <NUM> is being illustrated as a trailer system <NUM>, as seen in <FIG>. Although described herein that the transport refrigeration system <NUM> may be attached to a trailer, it should be appreciated that the transport refrigeration system <NUM> described herein may be suitable for any refrigerated cargo system (e.g., trailer, container, unit load device, etc.). When embodied as a trailer system <NUM>, the trailer system <NUM> includes a vehicle <NUM> integrally connected to a transport container <NUM>. The vehicle <NUM> may include an operator's compartment or cab <NUM> and a propulsion motor <NUM> which acts as the drive system of the trailer system <NUM>. The propulsion motor <NUM> is configured to power the vehicle <NUM>. The energy source that powers the propulsion motor <NUM> may be at least one of compressed natural gas, liquefied natural gas, gasoline, electricity, diesel, hydrogen, electricity from a fuel cell, a electricity from a hydrogen fueled proton exchange membrane (PEM) fuel cell, electricity from a battery, electricity from a generator, or any combination thereof. The propulsion motor <NUM> may be an electric motor or a hybrid motor (e.g., a combustion engine and an electric motor). The transport container <NUM> is coupled to the vehicle <NUM>. The transport container <NUM> may be removably coupled to the vehicle <NUM>. The transport container <NUM> is a refrigerated trailer and includes a top wall <NUM>, a directly opposed bottom wall <NUM>, opposed side walls <NUM>, and a front wall <NUM>, with the front wall <NUM> being closest to the vehicle <NUM>. The transport container <NUM> further includes a door or doors <NUM> at a rear wall <NUM>, opposite the front wall <NUM>. The walls of the transport container <NUM> define a refrigerated cargo space <NUM>. It is appreciated by those of skill in the art that embodiments described herein may be applied to a tractor-trailer refrigerated system or non-trailer refrigeration such as, for example a rigid truck, a truck having refrigerated compartment, or a shipping container having a refrigerated compartment.

Typically, transport refrigeration systems <NUM> are used to transport and distribute perishable goods and environmentally sensitive goods (herein referred to as perishable goods <NUM>). The perishable goods <NUM> may include but are not limited to fruits, vegetables, grains, beans, nuts, eggs, dairy, seed, flowers, meat, poultry, fish, ice, blood, pharmaceuticals, or any other suitable cargo requiring temperature controlled transport. The transport refrigeration system <NUM> includes a transport refrigeration unit <NUM>, a refrigerant compression device <NUM>, an electric motor <NUM> for driving the refrigerant compression device <NUM>, and a controller <NUM>. The transport refrigeration unit <NUM> is in operative association with the refrigerated cargo space <NUM> and is configured to provide conditioned air to the transport container <NUM>. The transport refrigeration unit <NUM> functions, under the control of the controller <NUM>, to establish and regulate a desired environmental parameters, such as, for example temperature, pressure, humidity, carbon dioxide, ethylene, ozone, light exposure, vibration exposure, and other conditions in the refrigerated cargo space <NUM>, as known to one of ordinary skill in the art. In an embodiment, the transport refrigeration unit <NUM> is capable of providing a desired temperature, carbon dioxide, and humidity range.

The transport refrigeration unit <NUM> includes a refrigerant compression device <NUM>, a refrigerant heat rejection heat exchanger <NUM>, an expansion device <NUM>, and a refrigerant heat absorption heat exchanger <NUM> connected in refrigerant flow communication in a closed loop refrigerant circuit and arranged in a conventional refrigeration cycle. The transport refrigeration unit <NUM> also includes one or more fans <NUM> associated with the refrigerant heat rejection heat exchanger <NUM> and driven by fan motor(s) <NUM> and one or more fans <NUM> associated with the refrigerant heat absorption heat exchanger <NUM> and driven by fan motor(s) <NUM>. The transport refrigeration unit <NUM> may also include a heater <NUM> associated with the refrigerant heat absorption heat exchanger <NUM>. In an embodiment, the heater <NUM> may be an electric resistance heater. It is to be understood that other components (not shown) may be incorporated into the refrigerant circuit as desired, including for example, but not limited to, a suction modulation valve, a receiver, a filter/dryer, an economizer circuit.

The refrigerant heat rejection heat exchanger <NUM> may, for example, comprise one or more refrigerant conveying coiled tubes or one or more tube banks formed of a plurality of refrigerant conveying tubes across flow path to the heat outlet <NUM>. The fan(s) <NUM> are operative to pass air, typically ambient air, across the tubes of the refrigerant heat rejection heat exchanger <NUM> to cool refrigerant vapor passing through the tubes. The refrigerant heat rejection heat exchanger <NUM> may operate either as a refrigerant condenser, such as if the transport refrigeration unit <NUM> is operating in a subcritical refrigerant cycle or as a refrigerant gas cooler, such as if the transport refrigeration unit <NUM> is operating in a transcritical cycle.

The refrigerant heat absorption heat exchanger <NUM> may, for example, also comprise one or more refrigerant conveying coiled tubes or one or more tube banks formed of a plurality of refrigerant conveying tubes extending across flow path from a return air intake <NUM>. The fan(s) <NUM> are operative to pass air drawn from the refrigerated cargo space <NUM> across the tubes of the refrigerant heat absorption heat exchanger <NUM> to heat and evaporate refrigerant liquid passing through the tubes and cool the air. The air cooled in traversing the refrigerant heat absorption heat exchanger <NUM> is supplied back to the refrigerated cargo space <NUM> through a refrigeration unit outlet <NUM>. It is to be understood that the term "air" when used herein with reference to the atmosphere within the cargo box includes mixtures of air with other gases, such as for example, but not limited to, nitrogen or carbon dioxide, sometimes introduced into a refrigerated cargo box for transport of perishable produce.

Airflow is circulated into and through the refrigerate cargo space <NUM> of the transport container <NUM> by means of the transport refrigeration unit <NUM>. A return airflow <NUM> flows into the transport refrigeration unit <NUM> from the refrigerated cargo space <NUM> through the refrigeration unit return air intake <NUM>, and across the refrigerant heat absorption heat exchanger <NUM> via the fan <NUM>, thus conditioning the return airflow <NUM> to a selected or predetermined temperature. The conditioned return airflow <NUM>, now referred to as supply airflow <NUM>, is supplied into the refrigerated cargo space <NUM> of the transport container <NUM> through the refrigeration unit outlet <NUM>. Heat <NUM> is removed from the refrigerant heat rejection heat exchanger <NUM> through the heat outlet <NUM>. The transport refrigeration unit <NUM> may contain an external air inlet <NUM>, as shown in <FIG>, to aid in the removal of heat <NUM> from the refrigerant heat rejection heat exchanger <NUM> by pulling in external air <NUM>. The supply airflow <NUM> may cool the perishable goods <NUM> in the refrigerated cargo space <NUM> of the transport container <NUM>. It is to be appreciated that the transport refrigeration unit <NUM> can further be operated in reverse to warm the transport container <NUM> when, for example, the outside temperature is very low. In the illustrated embodiment, the return air intake <NUM>, the refrigeration unit outlet <NUM>, the heat outlet <NUM>, and the external air inlet <NUM> are configured as grilles to help prevent foreign objects from entering the transport refrigeration unit <NUM>.

The transport refrigeration system <NUM> also includes a controller <NUM> configured for controlling the operation of the transport refrigeration system <NUM> including, but not limited to, the operation of various components of the refrigerant unit <NUM> to provide and maintain a desired thermal environment within the refrigerated cargo space <NUM>. The controller <NUM> may also be able to selectively operate the electric motor <NUM>. The controller <NUM> may also be configured to provide a feedforward signal to the fuel cell <NUM> so that it will start up before the transport refrigeration unit <NUM> places a load on the fuel cell <NUM>.

The controller <NUM> may be an electronic controller including a processor and an associated memory comprising computer-executable instructions that, when executed by the processor, cause the processor to perform various operations. The processor may be but is not limited to a single-processor or multi-processor system of any of a wide array of possible architectures, including field programmable gate array (FPGA), central processing unit (CPU), application specific integrated circuits (ASIC), digital signal processor (DSP) or graphics processing unit (GPU) hardware arranged homogenously or heterogeneously. The memory may be a storage device such as, for example, a random access memory (RAM), read only memory (ROM), or other electronic, optical, magnetic or any other computer readable medium. The controller <NUM> may have multiple inputs (e.g. analog, digital, others) and multiple outputs and a communication interface (e.g. CAN-bus, ethernet).

The transport refrigeration unit <NUM> is powered by a fuel cell <NUM> and/or an energy storage device <NUM>. The fuel cell <NUM>, associated fuel tanks <NUM>, and energy storage device <NUM> may be attached to the trailer system <NUM>. The fuel cell <NUM>, associated fuel tanks <NUM>, and energy storage device <NUM> may be attached to a bottom of the trailer system <NUM>.

The fuel cell <NUM> may include an anode electrode and a cathode electrode separated by an electrolyte (not shown for simplicity). A reducing fluid such as hydrogen is supplied to the anode electrode, and an oxidant such as oxygen or air is supplied to the cathode electrode. In a cell utilizing a PEM as the electrolyte, the hydrogen electrochemically reacts at a catalyst surface of the anode electrode to produce hydrogen ions and electrons. The electrons are conducted to an external load circuit (e.g., the transport refrigeration unit <NUM> or energy storage device <NUM>) and then returned to the cathode electrode, while the hydrogen ions transfer through the electrolyte to the cathode electrode, where they react with the oxidant and electrons to produce water and release thermal energy. A fuel tank <NUM> is configured to store and provide the reducing fluid to the fuel cell <NUM>. In an embodiment, the reducing fluid is hydrogen.

There may be one or more fuel cells <NUM> and one or more fuel tanks <NUM>. In one embodiment, the fuel cell <NUM> may be located inside the transport refrigeration unit <NUM>, as shown in <FIG>. In another embodiment, the fuel cell <NUM> may be located outside of the transport refrigeration unit <NUM>, as shown in <FIG>. The fuel cell <NUM> may be located under the transport container <NUM> of the trailer system <NUM>.

In one embodiment, the fuel tank <NUM> may be located inside the transport refrigeration unit <NUM>. In another embodiment, the fuel tank <NUM> may be located outside of the transport refrigeration unit <NUM>, as shown in <FIG>. The fuel tank <NUM> may be located under the transport container <NUM> of the trailer system <NUM>, as shown in <FIG>.

In one embodiment, the one or more supplemental power sources <NUM> may be located outside of the transport refrigeration unit <NUM>, as shown in <FIG>. In another embodiment, the one or more supplemental power sources <NUM> may be located within the transport refrigeration unit <NUM>. The one or more supplemental power sources <NUM> may include an energy storage device <NUM>, a thermal storage system <NUM>, and/or an electric generation device <NUM>. The fuel cell <NUM> may power the transport refrigeration unit <NUM> directly or may provide electricity to an energy storage device <NUM>, which then provides power to the transport refrigeration unit <NUM>.

The thermal storage system <NUM> does not directly provide electricity to the transport refrigeration unit <NUM> but rather the thermal storage system <NUM> may be used to save electricity used by the transport refrigeration unit <NUM> by providing supplemental or replacement heating or cooling to the transport container <NUM>. A thermal storage system <NUM> may be present to sink electrical energy into in order to cool the transport container <NUM>. The thermal storage system <NUM> may utilized a phase change material to provided cooling to the transport container <NUM>. For example, the thermal storage system <NUM> may utilized electricity to change the phase change material from one phase to another phase to cool the transport container <NUM>. The thermal storage system <NUM> may be an ice generation system to create ice to cool the transport container <NUM>. The ice generation system may generate ice when electricity is available or plentiful to provide lasting cooling for the transport container <NUM> to conserve electricity later by reducing use of the compression device <NUM> for cooling.

The energy storage device <NUM> may include a battery system <NUM>, a capacitor <NUM>, and/or any other electricity storage system known to one of skill in the art. The battery system <NUM> may comprise, chemical batteries, lithium-ion batteries, solid state batteries, flow batteries, or any other type of battery known to one of skill in the art. The battery system <NUM> may employ multiple batteries organized into battery banks. The capacitor <NUM> may be an electrolytic capacitor, a mica capacitor, a paper capacitor a film capacitor, a non-polarized capacitor, a ceramic capacitor, or any type of capacitor known to one of skill in the art.

The electricity generated by the electric generation device <NUM> may charge the energy storage device <NUM> or directly power the transport refrigeration unit <NUM>. The electric generation device <NUM> may include axle generator <NUM>, hub generator <NUM>, and/or any other electricity generation system known to one of skill in the art.

The axle generator <NUM> is configured to recover rotational energy when the transport refrigeration system <NUM> is decelerating or going downhill and convert that rotational energy to electrical energy, such as, for example, when the axle <NUM> of the trailer system <NUM> is rotating due to acceleration, cruising, or braking. The electricity generated by the axle generator <NUM> may be sent directly to the transport refrigeration unit <NUM>, the energy storage device <NUM>, or the thermal storage system <NUM>. The axle generator <NUM> may be mounted on or operably connected to a wheel axle <NUM> of the trailer system <NUM>. It is understood that the axle generator <NUM> may be mounted on any axle <NUM> of the trailer system <NUM> and the mounting location of the axle generator <NUM> illustrated in <FIG> is one example of a mounting location. The axle generator <NUM> may be operably connected to the axle <NUM> through at least one mechanical linkage, such as, for example a drive shaft, belt system, or gear system. The mechanical linkage configured to rotate the axle generator <NUM> as the axle <NUM> rotates when the axle generator <NUM> is activated. The axle generator <NUM> may comprise a single on-board, engine driven AC generator configured to generate alternating current (AC) power including at least one AC voltage at one or more frequencies. In an embodiment, the axle generator <NUM> may, for example, be a permanent magnet AC generator, asynchronous generator, or a synchronous AC generator. In another embodiment, the axle generator <NUM> may comprise a single on-board, engine driven DC generator configured to generate direct current (DC) power at at least one voltage.

The hub generator <NUM> is configured to recover rotational energy when the transport refrigeration system <NUM> is decelerating or going downhill and convert that rotational energy to electrical energy, such as, for example, when the wheel <NUM> of the trailer system <NUM> is rotating due to acceleration, cruising, or braking. The electricity generated by the hub generator <NUM> may be sent directly to the transport refrigeration unit <NUM>, the energy storage device <NUM>, or the thermal storage system <NUM>. The hub generator <NUM> may be mounted on a wheel <NUM> of the trailer system <NUM>. It is understood that the hub generator <NUM> may be mounted on any wheel <NUM> of the trailer system <NUM> and the mounting location of the hub generator <NUM> illustrated in <FIG> is one example of a mounting location. The hub generator <NUM> may be operably connected to the wheel <NUM> through at least one mechanical linkage, such as, for example a drive shaft, belt system, or gear system. The mechanical linkage configured to rotate the hub generator <NUM> as the wheel <NUM> rotates when the hub generator <NUM> is activated. The hub generator <NUM> may comprise a single on-board, engine driven AC generator configured to generate alternating current (AC) power including at least one AC voltage at one or more frequencies. In an embodiment, the hub generator <NUM> may, for example, be a permanent magnet AC generator, asynchronous generator, or a synchronous AC generator. In another embodiment, the hub generator <NUM> may comprise a single on-board, engine driven DC generator configured to generate direct current (DC) power at at least one voltage.

An inertial sensor <NUM> may be present and configured to detect at least one of a deceleration of the vehicle <NUM> and a downward pitch of the vehicle <NUM> (e.g., indicating the vehicle <NUM> is moving downhill). The inertial sensor <NUM> may be a <NUM>-axis sensor. The inertial sensor <NUM> may be configured to detect three linear accelerations and two rotational accelerations. The three linear accelerations may be along an X-axis, a Y-axis, and a Z-axis of a three-dimensional Cartesian coordinate system. The rotational accelerations may be around two of the three axis of the three-dimensional cartesian coordinate system, such as, for example, the X-axis and the Z-axis. The inertial sensor <NUM> may accomplish this detection utilizing a plurality of connected sensors or a single sensor. In an embodiment, the inertial sensor <NUM> is a single sensor in electronic communication with a power management module <NUM>. The power management module <NUM> is configured to activate the axle generator <NUM> and/or the hub generator <NUM> when the inertial sensor <NUM> detects at least one of the deceleration of the vehicle <NUM> and the downward pitch of the vehicle <NUM>. The inertial sensor <NUM> may also include a GPS device in order to predict in advance at least one of the deceleration of the vehicle <NUM> and the downward pitch of the vehicle <NUM>.

The energy storage device510 may be charged by a stationary charging station <NUM> such as, for example a three-phase 460Vac (<NUM>) or 400Vac (<NUM>) power outlet. The charging station <NUM> may provide single phase (e.g., level <NUM> charging capability) or three phase AC power to the energy storage device <NUM>. It is understood that the charging station <NUM> may have any phase charging and embodiments disclosed herein are not limited to single phase or three phase AC power. In an embodiment, the single phase AC power may be a high voltage DC power, such as, for example, 500VDC. One function of the charging station <NUM> is to balance the cell voltage of individual cells of the battery system at some regular cadence.

The transport refrigeration unit <NUM> has a plurality of electrical power demand loads on the energy storage device <NUM>, including, but not limited to, the electric motor <NUM> for the compression device <NUM>, the drive motor <NUM> for the fan <NUM> associated with the refrigerant heat rejection heat exchanger <NUM>, and the drive motor <NUM> for the fan <NUM> associated with the refrigerant heat absorption heat exchanger <NUM>. As each of the fan motors <NUM>, <NUM> and the electric motor <NUM> may be an AC motor or a DC motor, it is to be understood that various power converters <NUM>, such as AC to DC rectifiers, DC to AC inverters, AC to AC voltage/frequency converters, DC to DC voltage converters, and filters, may be employed in connection with the energy storage device <NUM> as appropriate. In the depicted embodiment, the heater <NUM> also constitutes an electrical power demand load. The electric resistance heater <NUM> may be selectively operated by the controller <NUM> whenever a control temperature within the temperature controlled cargo box drops below a preset lower temperature limit, which may occur in a cold ambient environment. In such an event the controller <NUM> would activate the heater <NUM> to heat air circulated over the heater <NUM> by the fan(s) <NUM> associated with the refrigerant heat absorption heat exchanger <NUM>. The heater <NUM> may also be used to de-ice the refrigerant heat absorption heat exchanger <NUM>. Additionally, the electric motor <NUM> being used to power the refrigerant compression device <NUM> constitutes a demand load. The refrigerant compression device <NUM> may comprise a single-stage or multiple-stage compressor such as, for example, a reciprocating compressor or a scroll compressor. The transport refrigeration system <NUM> may also include a voltage sensor <NUM> to sense the voltage and phase coming into the transport refrigeration unit <NUM>. Additional power demand loads may include various controllers, battery chargers, stepper motor modules, display modules, power control modules, control box, refrigerant valves, coolant pumps, and any component of the transport refrigeration system <NUM> that may require power or accessories of <NUM>, such as lift gate.

The power demand loads of the transport refrigeration unit <NUM> may be managed and fulfilled by an energy management system <NUM>. The energy management system <NUM> may include the fuel cell <NUM> and/or the one or more supplemental power sources <NUM>. The energy management system <NUM> includes a power management module <NUM> that is in communication with transport refrigeration unit <NUM>, the fuel cell <NUM> and/or the one or more supplemental power sources <NUM>.

The power management module <NUM> may be an electronic controller including a processor and an associated memory comprising computer-executable instructions that, when executed by the processor, cause the processor to perform various operations. The processor may be but is not limited to a single-processor or multi-processor system of any of a wide array of possible architectures, including field programmable gate array (FPGA), central processing unit (CPU), application specific integrated circuits (ASIC), digital signal processor (DSP) or graphics processing unit (GPU) hardware arranged homogenously or heterogeneously. The memory may be a storage device such as, for example, a random access memory (RAM), read only memory (ROM), or other electronic, optical, magnetic or any other computer readable medium.

The power management module <NUM> is configured to control electricity to transport refrigeration unit <NUM> from the fuel cell <NUM> and/or the one or more supplemental power sources <NUM>.

The fuel cell <NUM> may be the main source of electricity for the transport refrigeration unit <NUM> and may provide all or a majority of the electricity for the transportation for the transport refrigeration unit <NUM> during normal operation. However, the fuel cell <NUM> may not be able to provide an appropriate amount of electricity to the transport refrigeration unit <NUM> during certain conditions, such as, when the transport refrigeration unit <NUM> is in a low load condition, during a rapid ramp condition (e.g., rapid pull down), at a max load condition, or other conditions. The fuel cells <NUM> may not handle low load conditions for the transport refrigeration unit <NUM> particularly well because some fuel cells <NUM> in one example may have issues with providing <<NUM>% of the rated power from their fuel cell system or <NUM> kWe of power from their fuel cell system in a low load condition as it could cause a very high cell voltage (><NUM>. 84V), which may be bad for the electrodes. Fuel cells <NUM> do not handle rapid ramp conditions for the transport refrigeration unit <NUM> particularly well because the fuel cells <NUM> cannot react fast to rapid changes of power needs. The power management module <NUM> is in communication with the controller <NUM> of the transport refrigeration unit <NUM> and the controller <NUM> will inform the power management module <NUM> of a low load condition or a rapid ramp condition. During a low load condition or a rapid ramp condition of the transport refrigeration unit <NUM>, the power management module <NUM> is configured to provide all or a portion of the electricity demanded by the transport refrigeration unit <NUM> from the one or more supplemental power sources <NUM>. For example, the fuel cell <NUM> may be configured to provide the electricity to the transport refrigeration unit <NUM> and the one or more supplemental power sources <NUM> may provide supplemental electricity.

A low load condition may be defined as when the transport refrigeration unit <NUM> is requiring a low load of electricity from the fuel cell <NUM>. In on example a lower load be defined as less than <NUM>% of the rated power of the fuel cell system or 2kWe. A rapid ramp condition may be defined as when an inrush of current is required by the transport refrigeration unit <NUM>. An inrush of current may occur when controller <NUM> turns on fans <NUM>, <NUM> or the refrigeration compression device <NUM>. While the fuel cell <NUM> may have some capacitance and can take care of some of the inrush current, the inrush currents can best be caught by the battery, as there is no time to adjust the air flow and hydrogen recirculation rate of the fuel cell system.

Supplemental electricity provided by one or more supplemental power sources <NUM> may during a max load condition allow peak power capability that is beyond that which the fuel cell <NUM> alone can provide. This boost capability may allow for the fitment of a smaller and less expensive fuel cell while still meeting all system load requirements.

The power management module <NUM> may also be in communication with the inertial sensor <NUM> if present. The inertial sensor <NUM> is configured to detect a deceleration of the vehicle <NUM>. The inertial sensor <NUM> is in operative association with the vehicle <NUM> and may detect when a brake <NUM> of the vehicle <NUM> is being applied to slow the vehicle <NUM> and/or the vehicle <NUM> is decelerating without the brakes <NUM> being applied (i.e., driver lets foot off accelerator pedal). The inertial sensor <NUM> is in operative communication with the power management module <NUM> and the power management module <NUM> controls the operation of the inertial sensor <NUM>.

The power management module <NUM> is configured to activate the axle generator <NUM> and/or the hub generator <NUM> when the deceleration is greater than a selected deceleration, which may indicate that some propulsion motor <NUM> rotation is no longer needed to drive the vehicle <NUM> and it is a good time to bleed off some rotational energy of the wheels <NUM> or axle <NUM> of the trailer system <NUM> using the axle generator <NUM> and/or the hub generator <NUM>. Bleeding off rotational energy of the wheels <NUM> or axle <NUM> when the vehicle <NUM> is decelerating helps reduce any performance impact to the ability of the propulsion motor <NUM> to power the vehicle <NUM>.

The inertial sensor <NUM> is also configured to detect a pitch angle of the vehicle <NUM>. The power management module <NUM> is configured to activate the axle generator <NUM> and/or the hub generator <NUM> when the when the pitch angle is less than a selected pitch angle, which may indicate that some propulsion motor <NUM> rotation is no longer needed to drive the vehicle <NUM> and it is a good time to bleed off some rotational energy of the wheels <NUM> or axle <NUM> of the trailer system <NUM> using the axle generator <NUM> and/or the hub generator <NUM>. For example, when the vehicle <NUM> is descending downhill with a negative pitch angle, gravity assists in driving the vehicle <NUM> downhill and the full capacity of the e rotational energy of the wheels <NUM> and axle <NUM> may no longer be needed to drive the vehicle <NUM>. Bleeding off rotational energy of the wheels <NUM> or axle <NUM> when the vehicle <NUM> is descending downhill helps reduce any performance impact to the ability of the propulsion motor <NUM> to power the vehicle <NUM>.

The axle generator <NUM> and/or the hub generator <NUM> may also include a rotational velocity sensor 360a configured to measure the rotational velocity of the electric generation device <NUM> (e.g., rotations per minute (RPM)). The rotational velocity sensor 360a is in communication with the power management module <NUM> and the power management module <NUM> may control the operation of the rotational velocity sensor 360a. The power management module <NUM> is configured to determine when the vehicle <NUM> is decelerating utilizing the inertial sensor <NUM> and/or the rotational velocity sensor 360a, which may indicate that some propulsion motor <NUM> rotation is no longer needed to drive the vehicle <NUM> (i.e., the vehicle <NUM> is going downhill or decelerating) and it is a good time to bleed off some rotational energy of the wheels <NUM> or axle <NUM> of the trailer system <NUM> using the axle generator <NUM> and/or the hub generator <NUM>. Bleeding off rotational energy of the wheels <NUM> or axle <NUM> when the vehicle <NUM> is decelerating or going downhill helps reduce any performance impact to the ability of the propulsion motor <NUM> to power the vehicle <NUM>.

In one embodiment, the rotational velocity sensor 360a may be a sensor mechanically connected to the generator <NUM>, <NUM> to detect rotational velocity of the generator <NUM>, <NUM>. In another embodiment, the rotational velocity sensor 360a may be an electronic sensor electrically connected to the generator <NUM>, <NUM> to detect rotational velocity of the generator <NUM>, <NUM> by measuring the electrical frequency output of the generator <NUM>, <NUM>. In another embodiment, the rotational velocity sensor 360a may be an inverter connected to the generator <NUM>, <NUM> to detect rotational velocity of the generator <NUM>, <NUM> by measuring the electrical frequency output of the electric generation device <NUM>. In yet another embodiment, the rotational velocity sensor 360a may be a wireless sensor capable of detecting rotational velocity of the generator <NUM>, <NUM> wirelessly, such as, for example, RFID tracking, wireless capacitive sensor, wireless electromagnetic induction sensor, or any other wireless detection method known to one of skill in the art.

Referring now to <FIG>, with continued reference to <FIG> and <FIG>, a flow process of a method <NUM> of operating a transport refrigeration system <NUM> is illustrated, according to an embodiment of the present invention. In an embodiment, the method <NUM> may be performed by the power management module <NUM>.

At block <NUM>, electricity is provided from a fuel cell <NUM> to a transport refrigeration unit <NUM>. The transport refrigeration unit <NUM> configured to provide conditioned air to a refrigerated cargo space <NUM> of a transport container <NUM>. Prior to block <NUM>, the fuel cell <NUM> requires some electricity from the energy storage device <NUM> to start up.

At block <NUM>, the transport refrigeration unit <NUM> is powered using the electricity from the fuel cell <NUM>.

At block <NUM>, a condition of the transport refrigeration unit <NUM> that requires supplemental electricity is detected. The condition of the transport refrigeration unit <NUM> that requires supplemental electricity is at least one of a low load condition, a max load condition, or a rapid ramp condition.

At block <NUM>, supplemental electricity is provided from one or more supplemental power sources <NUM> to the transport refrigeration unit <NUM> during the condition of the transport refrigeration unit <NUM> that requires supplemental electricity.

At block <NUM>, the transport refrigeration unit <NUM> is powered using at least the supplemental electricity from the one or more supplemental power sources <NUM> during the condition of the transport refrigeration unit <NUM> that requires supplemental electricity. The one or more supplemental power sources <NUM> may include at least one of an energy storage device <NUM> configured to store electricity and provide electricity to the transport refrigeration unit <NUM> or an electric generation device <NUM> configured to generate electricity and provide the electricity to the transport refrigeration unit <NUM>. In an embodiment, the energy storage device <NUM> includes at least one of a battery system <NUM>, a capacitor <NUM>, or a thermal storage system <NUM>. In an embodiment, the electric generation device <NUM> includes at least one of an axle generator <NUM> or a hub generator <NUM>.

In an embodiment, the one or more supplemental power sources <NUM> may only provide the supplemental electricity to the transport refrigeration unit <NUM> during the condition of the transport refrigeration unit <NUM> that requires supplemental electricity.

The method <NUM> may also include that the one or more supplemental power sources <NUM> is activated only during the condition of the transport refrigeration unit <NUM> that requires supplemental electricity.

The method <NUM> may further include that electricity is provided from fuel cell <NUM> to the transport refrigeration unit <NUM> during the condition of the transport refrigeration unit <NUM> that requires supplemental electricity and the transport refrigeration unit <NUM> is powered using the supplemental electricity from the one or more supplemental power sources <NUM> and the electricity from the fuel cell <NUM> during the condition of the transport refrigeration unit <NUM> that requires supplemental electricity.

The fuel cell <NUM> may be configured to provide the electricity to the transport refrigeration unit <NUM> during all other conditions of the transport refrigeration unit <NUM> other than the low load condition or the rapid ramp condition of the transport refrigeration unit <NUM>. Further, the fuel cell <NUM> may be configured to provide all of the electricity required by the transport refrigeration unit <NUM> during all other conditions of the transport refrigeration unit <NUM> other than the low load condition or the rapid ramp condition of the transport refrigeration unit <NUM>.

As described above, embodiments can be in the form of processor-implemented processes and devices for practicing those processes, such as processor. Embodiments can also be in the form of computer program code (e.g., computer program product) containing instructions embodied in tangible media (e.g., non-transitory computer readable medium), such as floppy diskettes, CD ROMs, hard drives, or any other non-transitory computer readable medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes a device for practicing the embodiments. Embodiments can also be in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes a device for practicing the exemplary embodiments.

Claim 1:
A transport refrigeration system comprising:
a transport refrigeration unit (<NUM>) configured to provide conditioned air to a refrigerated cargo space (<NUM>) of a transport container (<NUM>);
a fuel cell (<NUM>) configured to provide electricity to the transport refrigeration unit (<NUM>);
one or more supplemental power sources (<NUM>) configured to provide supplemental electricity to the transport refrigeration unit (<NUM>); and
a power management module (<NUM>) configured to manage the electricity and the supplemental electricity provided to the transport refrigeration unit (<NUM>),
wherein the power management module (<NUM>) is configured to detect a condition of the transport refrigeration unit (<NUM>) that requires supplemental electricity and provide the supplemental electricity to the transport refrigeration unit (<NUM>) from the one or more supplemental power sources (<NUM>); characterized in that
the condition of the transport refrigeration unit (<NUM>) that requires supplemental electricity is at least one of a low load condition, a max load condition, or a rapid ramp condition.