Patent Description:
A transport climate control system (TCCS) can include, for example, a transport refrigeration system (TRS) and/or a heating, ventilation and air conditioning (HVAC) system. A TRS is generally used to control an environmental condition (e.g., temperature, humidity, air quality, and the like) within a cargo space of a transport unit (e.g., a truck, a container (such as a container on a flat car, an intermodal container, etc.), a box car, a semi-tractor, a passenger bus, or other similar transport unit). The TRS can maintain environmental condition(s) of the cargo space to maintain cargo (e.g., produce, frozen foods, pharmaceuticals, etc.). In some embodiments, the transport unit can include a HVAC system to control a climate within a passenger space of the vehicle.

<CIT> describes a method for comprehensive integrated control of an internal combustion engine utilizing an electronic control module. The control strategy integrates various functions of engine control including an acceleration balance test for the engine cylinders, a fuel economy vehicle speed limit adder, a fueling limit for high altitude vehicle operation, throttle logic, a data-hub for operation trending and vehicle component lifing analyses, a gear ratio torque limit, an air temperature based torque limit, enhanced cooling fan control, and an idle shutdown strategy based on ambient air temperature.

<CIT> describes a method and system for performing a regeneration cycle for regenerating a diesel particulate filter of a diesel engine associated with a refrigeration system having a refrigeration unit powered by the diesel engine.

This disclosure relates generally to adjusting a power output upper limit for a prime mover of a transport power system. More specifically, the disclosure relates to systems and methods for adjusting a power output upper limit for a prime mover of a transport power system that can be used, for example, for powering a TCCS and having an altitude sensor and configuring a DPF backpressure sensor as an altitude sensor.

Embodiments disclosed herein can use a single absolute pressure sensor (instead of a gauge pressure sensor) as a DPF backpressure sensor (which can be used or operated when the prime mover is running to determine particulate matter and/or soot accumulation, i.e., to determine how full the DPF is), and as a sensor to deduce the altitude of the transport power system (when the prime mover is not running). Embodiments disclosed herein can provide a controller to adjust a power usage/limit of the prime mover based on the altitude, and to vary the DPF fill level as a function of altitude.

Embodiments disclosed herein can also use an absolute pressure sensor to deduce the altitude of the transport power system so that a controller can adjust the power usage/limit of the prime mover based on the altitude of the transport power system.

It will be appreciated that in some embodiments the prime mover (e.g., a diesel engine, a mechanical engine and/or hybrid engine, or the like), is not solely an electronic engine. Also, the prime mover may not be the prime mover used for operating the vehicle. That is, the prime mover disclosed herein can be separate from and/or independent to the prime mover used for operating the vehicle. In some applications, when the prime mover used for operating the vehicle is running, the prime mover (e.g., a diesel engine of the transport power system, or the like) disclosed herein typically can be off, and vice versa.

The invention as claimed in the attached independent claims includes a transport power system as defined in claim <NUM> and a method for controlling an operation of a transport power system as defined in claim <NUM>.

Other features and aspects will become apparent by consideration of the following detailed description and accompanying drawings.

References are made to the accompanying drawings that form a part of this disclosure and which illustrate the embodiments in which systems and methods described in this specification can be practiced.

This disclosure relates generally to adjusting a power output upper limit for a prime mover of a transport power system. More specifically, the disclosure relates to systems and methods for adjusting a power output upper limit for a prime mover of a transport power system that can be used, for example, for powering a transport climate control system (TCCS) and having an altitude sensor and/or configuring a diesel particulate filter (DPF) backpressure sensor as an altitude sensor.

As defined herein, the phrase "diesel particulate filter" or "DPF" may refer to a device designed to remove e.g., diesel particulate matter, soot, or the like from the exhaust gas of a prime mover (e.g., a diesel powered compression ignition engine, or the like). It will be appreciated that unless specified otherwise, a prime mover described herein refers to a prime mover of a transport power system (e.g., a prime mover of an auxiliary power unit (APU), a prime mover of a TCCS, or the like), but not to a vehicle prime mover. That is, in some embodiments, there can be two or more distinct diesel engines on a same vehicle: one can be a main/vehicle (e.g., tractor, truck, or the like) engine used to move the vehicle, and the other can be an auxiliary engine (e.g., a diesel powered compression ignition engine) of the transport power system. Typically when the main/vehicle engine is running, the auxiliary engine is off, and vice versa. It will be appreciated that in some embodiments an electronic prime mover might not work with a diesel particulate filter. Embodiments disclosed herein can be directed to the diesel particulate filter for the auxiliary diesel powered compression ignition engine.

It will be appreciated that some embodiments of the DPF and the DPF regeneration are described in <CIT> and <CIT>, which are incorporated by reference herein in their entirety.

As defined herein, the phrase "absolute pressure" may refer to a pressure measured relative to a full/absolute vacuum. A full vacuum has an absolute pressure reading of <NUM> pounds per square inch absolute (PSIA) (0kPa) and an average barometric pressure at sea level is at or about <NUM> PSIA (<NUM>,529kPa). It will be appreciated that absolute pressure sensor(s) such as altimeters, barometers, or the like can produce readings that are not influenced by atmospheric pressure or weather. The absolute pressure sensor can use full vacuum as its zero point, and can read different pressures as a function of altitude. In contrast, a pressure that is measured against atmospheric pressure (also known as barometric pressure) can be called a gauge pressure. A gauge pressure can be referred to as a pressure of a system above atmospheric pressure. Gauge pressure can be zero-referenced against ambient air (or atmospheric) pressure, so gauge pressure readings include the pressure from the weight of the atmosphere. That is, a gauge pressure sensor reads <NUM> pounds per square inch (PSI) regardless of altitude and uses the ambient pressure as its zero point.

Embodiments disclosed herein can be applicable to e.g., box truck, self-powered truck, trailer, TRU, or the like, or dual prime mover system where a prime mover is independent to a vehicle prime mover. It will be appreciated that the control of the components of the system can be performed by a controller (e.g., the APU controller, the TCCS controller, or the like). Also, the embodiments described herein can also be applicable to a hybrid power system that uses both a prime mover and a rechargeable energy storage (e.g., battery).

<FIG> illustrates one embodiment of a MTRS <NUM> for a TU <NUM> that can be towed, for example, by a tractor (not shown). The MTRS <NUM> includes a TRU <NUM> and a plurality of remote evaporator units <NUM>. The TRU <NUM> and each of the remote evaporator units <NUM> provide climate control (e.g. temperature, humidity, air quality, etc.) within a separate zone of the internal space <NUM>. The TRU <NUM> can include, amongst other components, a refrigeration circuit that connects, for example, a compressor, a condenser, an evaporator and an expansion valve to provide climate control within the at least one of the zones of the internal space <NUM>. Each of the evaporator units <NUM> can also be connected to the refrigeration circuit to provide climate control to a particular zone <NUM> of the internal space <NUM>.

The MTRS <NUM> also includes a MTRS controller <NUM> and one or more sensors (e.g., Hall effect sensors, current transducers, etc.) that are configured to measure one or more parameters (e.g., ambient temperature, compressor suction pressure, compressor discharge pressure, supply air temperature, return air temperature, humidity, etc.) of the MTRS <NUM> and communicate parameter data to the MTRS controller <NUM>. The MTRS <NUM> is powered by a power module <NUM>. The TRU <NUM> is disposed on a front wall <NUM> of the TU <NUM>. In other embodiments, it will be appreciated that the TRU <NUM> can be disposed, for example, on a rooftop <NUM> or another wall of the TU <NUM>.

In some embodiments, the MTRS <NUM> can include an undermount unit <NUM>. In some embodiments, the undermount unit <NUM> can be a TRU that can also provide environmental control (e.g. temperature, humidity, air quality, etc.) within the internal space <NUM> of the TU <NUM>. The undermount unit <NUM> can work in combination with the TRU <NUM> to provide redundancy or can replace the TRU <NUM>. Also, in some embodiments, the undermount unit <NUM> can be a power module that includes, for example, a generator that can help power the TRU <NUM>.

The programmable MTRS Controller <NUM> may comprise a single integrated control unit or may comprise a distributed network of TRS control elements. The number of distributed control elements in a given network can depend upon the particular application of the principles described herein. The MTRS controller <NUM> is configured to control operation of the MTRS <NUM>.

As shown in <FIG>, the power module <NUM> is disposed in the TRU <NUM>. In other embodiments, the power module <NUM><NUM> can be separate from the TRU <NUM>. Also, in some embodiments, the power module <NUM> can include two or more different power sources disposed within or outside of the TRU <NUM>. In some embodiments, the power module <NUM> can include one or more of a prime mover, a battery, an alternator, a generator, a solar panel, a fuel cell, etc. Also, the prime mover can be a combustion engine or a microturbine engine and can operate as a two speed prime mover, a variable speed prime mover, etc. In some embodiments, for the prime mover, an absolute pressure sensor (configured to sense/measure an absolute pressure) and a DPF (configured to collect particulate such as carbon, soot, or the like that comes out of the tail pipe) can be provided. The power module <NUM> can provide power to, for example, the MTRS Controller <NUM>, a compressor (not shown), a plurality of DC (Direct Current) components (not shown), a power management unit (not shown), etc. The DC components can be accessories or components of the MTRS <NUM> that require DC power to operate. Examples of the DC components can include, for example, DC fan motor(s) for a condenser fan or an evaporator blower (e.g., an Electrically Commutated Motor (ECM), a Brushless DC Motor (BLDC), etc.), a fuel pump, a drain tube heater, solenoid valves (e.g., controller pulsed control valves), etc..

The power module <NUM> can include a DC power source (not shown) for providing DC electrical power to the plurality of DC components (not shown), the power management unit (not shown), etc. The DC power source can receive mechanical and/or electrical power from, for example, a utility power source (e.g., Utility power, etc.), a prime mover (e.g., a combustion engine such as a diesel engine, etc.) coupled with a generator machine (e.g., a belt-driven alternator, a direct drive generator, etc.), etc. For example, in some embodiments, mechanical energy generated by a diesel engine is converted into electrical energy via a generator machine. The electrical energy generated via the belt driven alternator is then converted into DC electrical power via, for example, a bi-directional voltage converter. The bi-directional voltage converter can be a bi-directional multi-battery voltage converter.

The internal space <NUM> can be divided into a plurality of zones <NUM>. The term "zone" means a part of an area of the internal space <NUM> separated by walls <NUM>. It will be appreciated that the invention disclosed herein can also be used in a single zone TRS.

The MTRS <NUM> for the TU <NUM> includes the TRU <NUM> and a plurality of remote evaporator units <NUM>. In some embodiments, an HVAC system can be powered by an Auxiliary Power Unit (APU, see <FIG>). The APU can be operated when a main prime mover of the TU <NUM> is turned off such as, for example, when a driver parks the TU <NUM> for an extended period of time to rest. The APU can provide, for example, power to operate a secondary HVAC system to provide conditioned air to a cabin of the tractor (not shown). The APU can also provide power to operate cabin accessories within the cabin such as a television, a microwave, a coffee maker, a refrigerator, etc. The APU can be a mechanically driven APU (e.g., prime mover driven) or an electrically driven APU (e.g., battery driven).

The tractor includes a vehicle electrical system for supplying electrical power to the electrical loads of the tractor, the MTRS <NUM>, and/or the TU <NUM>.

<FIG> illustrates a vehicle <NUM> according to one embodiment. The vehicle <NUM> is a semi-tractor that is used to transport cargo stored in a cargo compartment (e.g., a container, a trailer, etc.) to one or more destinations. Hereinafter, the term "vehicle" shall be used to represent all such tractors and trucks, and shall not be construed to limit the present application solely to a tractor in a tractor-trailer combination. In some embodiments, the vehicle <NUM> can be, for example, a straight truck, van, etc..

The vehicle <NUM> includes a primary power source <NUM>, a cabin <NUM> defining a sleeping portion <NUM> and a driving portion <NUM>, an APU <NUM>, and a plurality of vehicle accessory components <NUM> (e.g., electronic communication devices, cabin lights, a primary and/or secondary HVAC system, primary and/or secondary HVAC fan(s), sunshade(s) for a window/windshield of the vehicle <NUM>, cabin accessories, etc.). The cabin <NUM> can be accessible via a driver side door (not shown) and a passenger side door <NUM>. The cabin <NUM> can include a primary HVAC system (not shown) that can be configured to provide conditioned air within driving portion <NUM> and potentially the entire cabin <NUM>, and a secondary HVAC system (not shown) for providing conditioned air within the sleeping portion <NUM> of the cabin <NUM>. The cabin <NUM> can also include a plurality of cabin accessories (not shown). Examples of cabin accessories can include, for example, a refrigerator, a television, a video game console, a microwave, device charging station(s), a continuous positive airway pressure (CPAP) machine, a coffee maker, a secondary HVAC system for providing conditioned air to the sleeping portion <NUM>.

The primary power source <NUM> can provide sufficient power to operate (e.g., drive) the vehicle <NUM> and any of the plurality of vehicle accessory components <NUM> and cabin accessory components <NUM>. The primary power source <NUM> can also provide power to the primary HVAC system and the secondary HVAC system. In some embodiments, the primary power source can be a prime mover such as, for example, a combustion engine (e.g., a diesel engine, etc.).

The APU <NUM> is a secondary power unit for the vehicle <NUM> when the primary power source <NUM> is unavailable. When, for example, the primary power source <NUM> is unavailable, the APU <NUM> can be configured to provide power to one or more of the vehicle accessory components, the cabin accessories, the primary HVAC system and the secondary HVAC system. In some embodiments, the APU <NUM> can be an electric powered APU. In other embodiments, the APU <NUM> can be a prime mover powered APU. The APU <NUM> can be attached to the vehicle <NUM> using any attachment method. In some embodiments, the APU <NUM> can be turned on (i.e., activated) or off (i.e., deactivated) by an occupant (e.g., driver or passenger) of the vehicle <NUM>. The APU <NUM> generally does not provide sufficient power for operating (e.g., driving) the vehicle <NUM>. The APU <NUM> can be controlled by an APU controller <NUM>. In some embodiments, the APU <NUM> can include an absolute pressure sensor configured to sense/measure an absolute pressure and a DPF configured to collect particulate such as carbon, soot, or the like that comes out of the tail pipe.

<FIG> depicts a temperature-controlled straight truck <NUM> that includes a conditioned load space <NUM> for carrying cargo. A transport refrigeration unit (TRU) <NUM> is mounted to a front wall <NUM> of the load space <NUM>. The TRU <NUM> is controlled via a controller <NUM> to provide temperature control within the load space <NUM>. The truck <NUM> further includes a vehicle power bay <NUM>, which houses a truck prime mover <NUM>, such as a combustion engine (e.g., diesel engine, etc.), that provides power to move the truck <NUM>. In some embodiments, the truck prime mover <NUM> can work in combination with an optional machine <NUM> (e.g., an alternator). The TRU <NUM> includes a prime mover <NUM>. In an embodiment, the prime mover <NUM> can be a combustion engine (e.g., diesel engine, etc.) to provide power to the TRU <NUM>. In some embodiments, for the prime mover <NUM>, an absolute pressure sensor (configured to sense/measure an absolute pressure) and a DPF (configured to collect particulate such as carbon, soot, or the like that comes out of the tail pipe) can be provided. In one embodiment, the TRU <NUM> includes a vehicle electrical system. Also, in some embodiments, the TRU <NUM> can be powered by the prime mover <NUM> in combination with a battery power source or by the optional machine <NUM>. In some embodiments, the TRU <NUM> can also be powered by the truck prime mover <NUM> in combination with a battery power source or the optional machine <NUM>.

While <FIG> illustrates a temperature-controlled straight truck <NUM>, it will be appreciated that the embodiments described herein can also apply to any other type of transport unit including, but not limited to, a van, a container (such as a container on a flat car, an intermodal container, etc.), a box car, or other similar transport unit.

<FIG> is a schematic of an auxiliary power unit (APU) <NUM> with an exhaust system <NUM>, according to an embodiment. As shown in <FIG>, the exhaust system <NUM> is coupled to the auxiliary power unit <NUM>. In the embodiment, the illustrated exhaust system <NUM> includes a control module <NUM>, a diesel particulate filter (DPF) <NUM>, a blower <NUM>, a pressure sensor <NUM>, a control switch <NUM>, a system indicator <NUM>, and/or an ambient temperature sensor <NUM>. The control module <NUM> can be electrically coupled to an electronic control unit <NUM> (ECU) of the auxiliary power unit <NUM> and to the other components of the exhaust system <NUM> to receive, process, and transmit information to and from the components. It will be appreciated that controls described herein can be performed by a controller (e.g., control module <NUM>, the controller of the transport refrigeration unit/system of <FIG> and <FIG>, the controller of the APU of <FIG>, or the like). The controller can connect to and control the components via e.g., wireless or wired connections. The control module <NUM> can also be coupled to an ignition <NUM> of the vehicle (see vehicle <NUM> of <FIG>) such that the control module <NUM> receives status information from the primary mover (see prime mover <NUM> of <FIG>) of the vehicle <NUM>. In the illustrated construction, the control module <NUM> can be a small engine control module (SECM) that is compatible with the prime mover (e.g., a diesel engine or the like) <NUM> of the auxiliary power unit <NUM>. The prime mover <NUM> can be, for example, a prime mover of the APU, a prime mover of the transport refrigeration unit/system of <FIG> and <FIG>, or the like. The prime mover <NUM> is separate from a prime mover used for operating a vehicle. The control module <NUM> receives ignition and engine running status from the auxiliary power unit <NUM> so that the control module <NUM> can monitor when and at what strength the auxiliary power unit <NUM> is running. The control module <NUM> is also operable to sends signals to the ECU <NUM> through relays <NUM>, <NUM> to interrupt and/or shutdown operation of the auxiliary power unit <NUM>.

The DPF <NUM> is positioned downstream of the prime mover <NUM> of the auxiliary power unit <NUM> to receive exhaust from the prime mover <NUM> through an exhaust pipe <NUM>. In the illustrated construction, the DPF <NUM> can be an electrically-powered active DPF or any suitable DPF. The DPF <NUM> includes a filter element <NUM> operable to remove particulate matter such as carbon, soot, or the like from exhaust exiting the prime mover <NUM>. In the illustrated construction, the filter element <NUM> can be a non-catalyzed, silicon-carbide wall-flow exhaust filter element, although other suitable filter elements may also or alternatively be employed. Exhaust flows from the prime mover <NUM>, through the exhaust pipe <NUM>, and into the DPF <NUM>. As the exhaust travels through the DPF <NUM>, the exhaust flows through the filter element <NUM> such that clean exhaust is released into the environment through an outlet <NUM> of the DPF <NUM>. During such operation, particulate matter and soot gradually build-up and collect on the filter element <NUM>. Once the amount of particulate matter accumulated on the filter element <NUM> reaches a certain level or threshold, the DPF <NUM> should be regenerated to clean the filter element <NUM>.

In the illustrated construction, the exhaust system <NUM> can also include a heating element <NUM> electrically coupled to the control module <NUM>. The heating element <NUM> can be positioned adjacent to or within the filter element <NUM> of the DPF <NUM> to heat the filter element <NUM> and thereby promote regeneration. The illustrated heating element <NUM> can be an integrated <NUM>-volt high current electrical coil operable to radiate heat for an extended period of time (e.g., one hour or more) to regenerate the filter element <NUM>. A contactor <NUM> can be electrically coupled between the control module <NUM> and the heating element <NUM> to help control the power input to the heating element <NUM>. In other constructions, other suitable regeneration promoting means may be employed as an alternative to or in conjunction with the illustrated heating element <NUM>.

The blower <NUM> can be coupled to the control module <NUM> through a relay <NUM>. In the illustrated construction, the blower <NUM> can be in communication with the exhaust pipe <NUM> to supply oxygenated ambient air, when a valve <NUM> is open, to exhaust exiting the prime mover <NUM> of the auxiliary power unit <NUM>. The ambient air helps sustain oxidation of particulate matter and soot in the exhaust during regeneration of the DPF <NUM>. The valve <NUM> (e.g., a solenoid valve) is positioned between the blower <NUM> and the exhaust pipe <NUM> and is also coupled to the control module <NUM> through the relay <NUM>. During normal operation of the auxiliary power unit <NUM> (i.e., not during regeneration of the DPF <NUM>), the valve <NUM> can be closed to inhibit exhaust in the pipe <NUM> from entering the blower <NUM>, and thereby bypassing the DPF <NUM>.

The pressure sensor <NUM> can be coupled to the DPF <NUM> and the control module <NUM> to notify the control module <NUM> when the DPF <NUM> should be regenerated. In the embodiment the pressure sensor <NUM> is a single sensor positioned upstream of the filter element <NUM> to measure exhaust backpressure within the DPF <NUM>. The measured backpressure pressure generally corresponds to a particulate matter accumulation level on the filter element <NUM>. When the measured backpressure reaches or exceeds a predetermined value (i.e., a regeneration threshold), the control module <NUM> notifies a user to initiate regeneration of the DPF <NUM> or starts a regeneration process. In some constructions, the regeneration threshold indicates when a sufficient amount of particulate matter has accumulated on the filter element <NUM> to support regeneration. In other constructions, the regeneration threshold is set a predetermined length of time before the particulate matter and soot accumulates to a level where the DPF <NUM> can no longer function properly. In the embodiment, the single pressure sensor <NUM> is an absolute pressure sensor as opposed to a gauge pressure sensor. As an absolute pressure sensor, the single pressure <NUM> is configured to sense an absolute pressure that can produce readings that are not influenced by atmospheric pressure or weather. The absolute pressure sensor can use full vacuum as its zero point, and can read different pressures as a function of altitude.

In further constructions, the exhaust system <NUM> may additionally or alternatively include an engine runtime sensor. In such constructions, the runtime sensor is coupled to the prime mover <NUM> and the ECU <NUM> of the auxiliary power unit <NUM>. The runtime sensor can monitor how long and/or at what speeds the prime mover <NUM> has been running. Similar to exhaust backpressure, engine runtime and operation speed generally correspond to the accumulation level of particulate matter and soot on the filter element <NUM> of the DPF <NUM>. After the prime mover <NUM> runs for a predetermined length of the time, the ECU <NUM> can signal the control module <NUM> to notify a user to initiate regeneration of the DPF <NUM>.

The control switch <NUM> can be electrically coupled to the control module <NUM> and is positioned within the cabin <NUM> (see <FIG>) of the vehicle <NUM>. The control switch <NUM> can allow a user (e.g., the driver or passenger of the vehicle <NUM>) to start regeneration of the DPF <NUM> at his or her convenience. Regeneration of the DPF <NUM> typically requires electrical power for an extended period of time (e.g., more than an hour). With the switch <NUM>, the user can initiate regeneration when he or she knows the primary vehicle prime mover <NUM> (see <FIG>) will be kept at or above e.g., approximately <NUM> revolutions per minute during this time. The DPF <NUM> can therefore be regenerated using only excess power from the primary prime mover <NUM>, without requiring supplemental power from vehicle batteries or from another external power source.

The illustrated control switch <NUM> can be a three-position switch that is movable between a home position, a regeneration position, and an off position. The control switch <NUM> can be normally biased to the home, or middle, position. In the home position, the auxiliary power unit <NUM> and the DPF <NUM> are operational such that the DPF <NUM> filters particulate matter and soot from exhaust exiting the prime mover <NUM> of the auxiliary power unit <NUM>. Actuating (e.g., depressing) the switch <NUM> to the regeneration, or upper, position initiates regeneration of the DPF <NUM>. In the illustrated construction, the regeneration position is a momentary position that begins the regeneration. Once released, the switch <NUM> is immediately biased back to the home position, but regeneration of the DPF <NUM> continues until it is completed or interrupted. Actuating (e.g., depressing) the switch <NUM> to the off, or lower, position cuts off power to the auxiliary power unit <NUM> and the DPF <NUM>, interrupting operation of the auxiliary power unit <NUM> and/or regeneration of the DPF <NUM>. In the illustrated construction, the off position is a latching position such that the switch <NUM> remains in the off position until it is manually actuated back to the home position or the regeneration position.

The illustrated control switch <NUM> can include a light emitting diode <NUM> (LED) that indicates the current status of the DPF <NUM>. In the illustrated construction, the LED <NUM> turns on to notify a user to regenerate the DPF <NUM> (e.g., when the measured exhaust backpressure reaches or exceeds a regeneration threshold). In some constructions, the LED <NUM> may blink while the DPF <NUM> is regenerating and/or may turn off when the auxiliary power unit <NUM> and the DPF <NUM> are disabled or otherwise shutdown. In other constructions, the switch <NUM> may include multiple LEDs and/or different types of indicators to notify a user of the status of the auxiliary power unit <NUM> and the DPF <NUM>.

The system indicator <NUM> can be electrically coupled to the control module <NUM> and can be positioned within a sleeping section of the cabin <NUM> (see <FIG>) of the vehicle <NUM>. The indicator <NUM> can generally provide the same information to a user as the control switch <NUM>, but at a different location within the vehicle cabin <NUM>. The illustrated indicator <NUM> includes a first LED <NUM> to notify a user of the current status of the DPF <NUM> (e.g., if the DPF <NUM> needs to be regenerated, is regenerating, and/or is off). The indicator <NUM> can also include a second LED <NUM> to notify the user if there is a fault with the auxiliary power unit <NUM> and/or the DPF <NUM>.

The ambient temperature sensor <NUM> can be electrically coupled to the control module <NUM> and is mounted to the frame or the body of the vehicle <NUM> (see <FIG>). In the illustrated construction, the temperature sensor <NUM> can be a thermistor or other suitable temperature sensing transducer. The temperature sensor <NUM> can monitor the temperature of the environment and outputs a signal indicative of the measured temperature to the control module <NUM>. Ambient temperature generally affects the rate at which particulate matter and soot accumulate on the filter element <NUM> of the DPF <NUM>. At relatively lower ambient temperatures, particulate matter and soot accumulate faster on the filter element <NUM>. At relatively higher ambient temperatures, particulate matter and soot accumulate slower on the filter element <NUM>. The control module <NUM> therefore can use the measured ambient temperature to adjust the regeneration threshold of the DPF <NUM>, thereby compensating for environmental effects on the exhaust system <NUM>.

It will be appreciated that the APU <NUM> or the TRU or the TCCS can include sensors (e.g., temperature, pressure, humidity, motion, voltage, current, battery status, battery charging level, or the like) or the APU <NUM> or the TRU or the TCCS can communicate with sensors associated or embedded with a cargo. The controller <NUM> of the APU <NUM> or the TRU or the TCCS can obtain data sensed by the sensors and control the settings of the components (e.g., the prime mover <NUM>, the DPF <NUM>, the pressure sensor <NUM>, or the like) of the TCCS or the APU <NUM>. In an embodiment, the prime mover <NUM> of the APU <NUM> can be a combustion engine (e.g., a diesel engine, or the like). The APU <NUM> can be configured to provide power to operate a plurality of cabin accessories such as a refrigerator, a television, a video game console, a microwave, device charging station(s), a continuous positive airway pressure (CPAP) machine, a coffee maker, a secondary HVAC system (that is independent to and/or in addition to a primary HVAC system) for providing conditioned air to the sleeping portion of the cabin. The primary HVAC system and/or the secondary HVAC system can each include a compressor (not shown).

<FIG> is a flow chart illustrating a method <NUM> of controlling an operation of a transport power system (e.g., an APU), according to an embodiment.

It will be appreciated that the method <NUM> disclosed herein can be conducted by a controller (e.g., the controller of the transport refrigeration unit/system of <FIG> and <FIG>, the controller of the APU of <FIG>, the control module of <FIG>, or any suitable processor(s)), unless otherwise specified. The controller can include a processor, memory, and/or communication ports to communicate with e.g., other components of the TCCS or APU or with equipment or systems located in proximity to the TCCS or APU or a cargo load. The controller can communicate with other components using e.g., powerline communications, Pulse Width Modulation (PWM) communications, Local Interconnect Network (LIN) communications, Controller Area Network (CAN) communications, etc., and using any suitable communications including wired and/or wireless, analog and/or digital communications. In an embodiment, the communication can include communications over telematics of the TCCS or APU, which the TCCS or APU may include or which may be communicatively connected to the TCCS (e.g., telematics equipment, mobile phone, vehicle communication system, etc.). The TCCS or APU can include sensors (e.g., temperature, pressure, humidity, motion, voltage, current, battery status, battery charging level, or the like) or the TCCS or APU can communicate with sensors associated or embedded with a cargo. The controller can obtain data sensed by the sensors and control the settings of the components (e.g., the prime mover <NUM>, the DPF <NUM>, the pressure sensor <NUM> of <FIG>, or the like) of the TCCS or APU.

It will also be appreciated that the method <NUM> can include one or more operations, actions, or functions depicted by one or more blocks. Although illustrated as discrete blocks, various blocks may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation. The method <NUM> begins at <NUM>.

At <NUM>, the controller determines an altitude of the transport power system based on an absolute pressure sensed (e.g., by an absolute pressure sensor such as the single pressure sensor <NUM> of <FIG>) during a start-up sequence of the transport power system prior to running of the prime mover of the transport power system.

It will be appreciated that when the prime mover used for operating the vehicle is running, the prime mover (e.g., a diesel engine of the transport power system, or the like) disclosed herein typically can be off, and vice versa. That is, during a start-up sequence (of the transport power system or of the prime mover of the transport power system), the prime mover used for operating the vehicle is off, the vehicle is in stationary, and the altitude of the vehicle (and the transport power system) is not changing (i.e., staying constant) throughout e.g., the entire time period when the transport power system or the prime mover of the transport power system is running. The start-up sequence can be referred to or defined as a sequence of actions that initialize the transport power system and prepare for a start of the prime mover of the transport power system (i.e., prior to running of the prime mover of the transport power system). During the start-up sequence, typically there is no build-ups (of the soot, etc.) and/or no backpressure in the exhaust system of the transport power system. In an embodiment, the absolute pressure sensor can be disposed in the exhaust stream of the transport power system prime mover and configured to measure/sense an (ambient) absolute pressure.

The absolute pressure sensor is configured or controlled to measure/sense a first absolute pressure during the start-up sequence. The controller determines or deduces an altitude based on the sensed first absolute pressure (e.g., via a look-up table, or the like).

The method <NUM> proceeds to <NUM>. At <NUM>, the controller adjusts a power output upper limit for the prime mover of the transport power system based on the altitude determined at <NUM>.

It will be appreciated that the transport power system and the prime mover of the transport power system can be bound by emissions regulations. For example, one of the emissions regulations is not to exceed (NTE, a regulation threshold that limits power output for emissions) limit. The NTE limit can be a power level that the transport power system or the transport power system prime mover are not allowed to exceed, because above such power level, the emissions of the prime mover can be too high to meet the regulation requirements. In an embodiment, for a particular transport power system, a <NUM>-cylinder diesel engine that is rated with the Environmental Protection Agency (EPA) can be a full power (e.g., <NUM>% power) engine and can be used as the prime mover of the transport power system, but the NTE limit can be a derated power at a certain altitude. The reason for the difference between these two values is that as the prime mover (engine) of the transport power system is used at higher altitudes, the emissions performance may decrease. The NTE value can be the power limit (e.g., the power output upper limit) of the prime mover at a first altitude (e.g., at or about <NUM>,<NUM> feet (<NUM>,<NUM>) above sea level). Without altitude sensing capability (e.g., no sensor to detect or deduce altitude), an assumption (that the transport power system/vehicle is always at the first altitude) may have to be made so that the NTE is at or below the derated power level, to avoid potential violation of the emissions regulations. That is, the transport power system (or the prime mover of the transport power system) may be under-utilized e.g., at an altitude lower than the first altitude where the emissions performance may increase compared with the emissions performance at the first altitude.

To account for the under-utilization issue, the altitude determined at <NUM> can be used for the controller to adjust a power output upper limit (e.g., the NTE limit) for the prime mover of the transport power system. For example, at the first altitude (e.g., at or about <NUM>,<NUM> feet (<NUM>,<NUM>) above sea level), the power output upper limit (e.g., the power limit or the NTE limit) of the prime mover of the transport power system can be at the derated power, to meet certain emissions regulation requirements. As the prime mover is used at higher altitudes, the emissions performance decreases. That is, when the prime mover is used at lower altitudes, the emissions performance increases. For example, when the altitude of the transport power system/vehicle decreases from the first altitude, the emissions performance of the prime mover of the transport power system increases, and the power output upper limit (e.g., the power limit or the NTE limit) of the prime mover of the transport power system can be greater than the derated power (e.g., up to the maximum capability of the prime mover at the full power at sea level), to meet the same emissions regulation requirements.

In an embodiment, to meet the same emissions regulation requirements, the controller can increase a power output upper limit (e.g., the NTE limit) for the prime mover of the transport power system (up to e.g., up to the maximum capability of the prime mover) when the altitude of the transport power system decreases; and the controller can decrease the power output upper limit (e.g., the NTE limit) for the prime mover of the transport power system when the altitude of the transport power system increases.

It will be appreciated that the controller can determine the power output upper limit (e.g., the NTE limit) for the prime mover of the transport power system based on the altitude e.g., using an altitude versus power curve or map, and/or using a lookup table, etc., so that the controller can control the allowable power of the transport power system below or within the limit level (i.e., set the limit as the maximum power that the transport power system can operate). The curve or map can be based on the manufacture specification, experimental results, simulation or the like.

It will also be appreciated that because of the altitude features disclosed herein, additional power of the prime mover of the transport power system can be used, allowing to utilize e.g., additional cooling power or battery charging power, while without the altitude features, the power consumption thereof may need to be managed and reduced.

The method <NUM> proceeds to <NUM>. At <NUM>, the controller controls an operation of the prime mover of the transport power system (TPS) or an operation of the transport power system so that the power output of the prime mover of the transport power system or the power output of the transport power system does not exceed the power output upper limit (e.g., adjusted/increased/decreased at <NUM>).

The method <NUM> proceeds to optional <NUM>. At <NUM>, the controller adjusts a backpressure upper limit for the DPF based on the determined altitude. It will be appreciated that the backpressure (e.g., the transport power system prime mover exhaust backpressure) can be referred to or defined as an exhaust gas pressure that is produced by the prime mover to overcome the hydraulic resistance of the exhaust system in order to discharge the gases into the atmosphere. A backpressure limit (e.g., an upper limit) can be used to determine when to regenerate the DPF.

Embodiments disclosed herein can enable varying the DPF fill level (e.g., soot fill level) as a function of the altitude. For a given backpressure limit, the actual amount of fill of the DPF can vary as a function of the altitude since the air density factors into how much backpressure can be generated. Embodiments disclosed herein can allow to potentially cut of an operation of the DPF (to regenerate the DPF) sooner or later as a function of the altitude to maintain peak performance and reliability of the DPF system.

It will be appreciated that the higher the altitude, the less air density, the less total exhaust resistance, the particulate matter increases, the allowable power (i.e., the power output limit) might have to go down (since more power associated with higher particulate matter), and the backpressure upper limit can be decreased (i.e., cutting of an operation of the DPF (to regenerate the DPF) sooner).

For example, at the first altitude (e.g., at or about <NUM>,<NUM> feet (<NUM>,<NUM>) above sea level), the controller can determine a backpressure upper limit (e.g., at or around <NUM> kilopascal (kPa)) for the DPF based on the first altitude for an operation condition of the DPF. When the altitude decreases (from the first altitude), the controller can increase the backpressure upper limit (e.g., to a number greater than <NUM> kPa) for the same operation condition of the DPF. At another altitude (e.g., at or about sea level), the controller can determine a backpressure upper limit for the DPF based on such altitude for an operation condition of the DPF. When the altitude increases (from such altitude), the controller can decrease the backpressure upper limit for the same operation condition of the DPF. For example, for at or about <NUM> kW power output of a prime mover of a transport power system at sea level, compared with <NUM> kW at a certain altitude (that is higher than sea level), there can be more particulate matter at such altitude than at sea level. Thus, at such altitude, if the particulate matter (emission) is to be limited, the allowable power output of the transport power system (e.g., the allowable power output of the prime mover of the transport power system) needs to be reduced, and/or the backpressure upper limit needs to be decreased, compared with those at sea level.

The method <NUM> proceeds to <NUM>. At <NUM>, the controller determines a backpressure for the DPF based on the first absolute pressure (sensed at <NUM>) and a second absolute pressure sensed when the prime mover of the transport power system is running. In an embodiment, the DPF can be disposed in an exhaust system of the transport power system. When the transport power system is running, particulate matter such as soot gradually builds-up and accumulates on the DPF. A second absolute pressure can be sensed by the absolute pressure sensor when the prime mover of the transport power system is running.

For example, the first absolute pressure sensed at <NUM> can be at or about <NUM> kPa. After a while, when the transport power system (and/or the prime mover of the transport power system) is running, the second absolute pressure (which can be greater than the first absolute pressure since the pressure is increasing when the prime mover of the transport power system is running) sensed can be at or about <NUM> kPa. The delta pressure (<NUM> kPa, a difference between the second absolute pressure sensed during the running of the transport power system and the first absolute pressure sensed at <NUM>) can be used as a backpressure for the DPF to compare with a backpressure upper limit (predetermined or adjusted/increased/decreased at <NUM>).

That is, the controller can use an absolute pressure sensor to determine a backpressure as a result of DPF filling, which can be used to determine how full the DPF is (to determine a fill level of the DPF). It will be appreciated that determining a backpressure for the DPF may only occur when the prime mover of the transport power system is running (the DPF fills up and there is more backpressure which can be determined based on the measurements of the absolute pressure sensor). When the prime mover of the transport power system is not running (e.g., during a start-up sequence or the like), the same/single absolute pressure sensor can be used to determine the altitude of the transport power system (e.g., based on the first absolute pressure sensed at <NUM>), which can be used to change the power output upper limit of the transport power system (e.g., to allow power usage over the derated power).

The method <NUM> proceeds to <NUM>. At <NUM>, the controller controls a regeneration of the DPF when the determined backpressure of the DPF is above a backpressure upper limit (or the backpressure upper limit adjusted/increased/decreased at <NUM>). The backpressure upper limit can be a DPF regeneration pressure. That is, the DPF needs pressure feedback since the DPF collects particulate matter such as soot overtime, builds backpressure in the exhaust system, needs to clean the particulate matter out, and needs to determine when to clean the particulate matter out by comparing the backpressure determined at <NUM> with a certain backpressure threshold (a predetermined backpressure upper limit or the backpressure upper limit adjusted/increased/ decreased at <NUM>).

That is, if the backpressure determined at <NUM> is higher than a backpressure upper limit (a predetermined backpressure upper limit or the backpressure upper limit adjusted at <NUM>), the controller is configured to control a regeneration of the DPF (as described herein). If the backpressure determined at <NUM> is at or lower than the backpressure upper limit (a predetermined backpressure upper limit or the backpressure upper limit adjusted at <NUM>), no action with respect to regeneration may be taken.

It will be appreciated that at a higher altitude, there can be less air density, and for a same operating condition, a smaller backpressure may be determined (i.e., less backpressure for the same air flow since the air has lower density). For example, given a <NUM> kPa delta pressure (the determined backpressure) at sea level, by increasing the altitude of the transport power system, the backpressure threshold (upper limit) may be lower (i.e., regenerating the DPF at a lower delta) because of the reduced density of the air (i.e., less total resistance) (since for a same amount of particulate matter to build up, the delta pressure at such altitude may be less than <NUM> kPa), so the altitude can be used to adjust the backpressure threshold regarding when to regenerate to e.g., prevent overloading filter of the DPF.

It will be appreciated that the orders of <NUM> to <NUM> may vary. For example, in an embodiment, (<NUM>, <NUM>) may occur before or after (<NUM>, <NUM>, <NUM>) or (<NUM>, <NUM>, <NUM>). In another embodiment, (<NUM>, <NUM>, <NUM>), (<NUM>, <NUM>, <NUM>), (<NUM>, <NUM>, <NUM>), (<NUM>, <NUM>, <NUM>), (<NUM>, <NUM>, <NUM>), or (<NUM>, <NUM>, <NUM>) may occur before (<NUM>, <NUM>) or (<NUM>, <NUM>).

The terminology used in this specification is intended to describe particular embodiments and is not intended to be limiting. The terms "a," "an," and "the" include the plural forms as well, unless clearly indicated otherwise. The terms "comprises" and/or "comprising," when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components.

Claim 1:
A transport power system (<NUM>, <NUM>) comprising:
a prime mover (<NUM>, <NUM>) powering a transport climate control system (TCCS) being separate from and independent to a vehicle prime mover (<NUM>, <NUM>) used for operating a vehicle (<NUM>, <NUM>);
a diesel particulate filter, DPF, (<NUM>) disposed in an exhaust system (<NUM>) of the transport power system;
a DPF backpressure sensor (<NUM>) upstream of the DPF configured to sense an absolute pressure; and
a controller (<NUM>, <NUM>),
wherein the controller is configured to:
determine (<NUM>) an altitude of the transport power system based on a first absolute pressure sensed by the DPF backpressure sensor during a start-up sequence of the transport power system prior to running of the prime mover,
adjust (<NUM>) a power output upper limit for the prime mover based on the determined altitude, and
control (<NUM>) an operation of the prime mover of the transport power system not to exceed the adjusted power output upper limit.