Patent Description:
Diesel engines, whether used to power vehicles, generators, pumps, or compressors, etc. are subject to environmental standards (e.g. Tier <NUM> Final) that now mandate widespread use of selective catalytic reduction (SCR) technology to reduce harmful nitrogen oxide (NOX) emissions. SCR technology injects a urea-based DEF into the exhaust system of a diesel generator upstream of a catalyst, where it vaporizes and decomposes to form ammonia and carbon dioxide. The ammonia and catalyst react with NOX, converting it to harmless nitrogen and water.

For standards compliance, DEF supply systems in diesel engines include an onboard DEF tank and controls necessary for causing injection of the DEF into the exhaust system when the engine is running. Diesel engine manufacturers must provide engine control modules (ECMs) that are programmed to automatically shut down the engine, or reduce engine power, in the event that DEF level or DEF quality drop below acceptable levels. Timely replenishment of the DEF therefore becomes critical, and so diesel engine operators must refill the onboard DEF tank manually, usually when adding fuel, to replenish DEF that is consumed during normal operation. Operators of diesel-powered vehicles such as trucks and tractors are able to maintain an operable level of DEF without difficulty, by topping off the onboard DEF tank during a refueling stop, or by carrying a refill supply on board for emergency use. Operators of diesel generators can similarly replenish the onboard DEF tank, provided that an operator is on duty and able to monitor DEF tank level.

Other problems arise, however, when deploying diesel engines in applications that require automatic unattended operation. For example, diesel engines are often run in locations remote from an electrical grid to drive stationary apparatus, such as electrical generators, pumps, and air compressors. These applications may require that the diesel engine run unattended for extended periods of time during which diesel fuel and DEF are continuously consumed. Although extended operation relies equally on timely replenishment of both diesel fuel and DEF, in practice diesel fuel supplies are generally more readily available to remote locations than are DEF supplies, due to supply and demand logistics. Periodic replenishment of the DEF tank can therefore become a critical path impediment to ensuring compliance with Tier-<NUM> Final (and future) standards for unattended operation of diesel engines for extended periods of time.

<CIT>) proposes a solution to this problem by providing, for a diesel generator set, both an onboard DEF tank and an auxiliary DEF supply system. The overall system relies on a generator control module, integral to the diesel generator set, to sense DEF level in the onboard DEF tank. When the sensed DEF level is low, the generator control module actuates a pump located in the auxiliary DEF supply system to transfer DEF from a bulk storage tank to the onboard DEF tank via an auxiliary DEF hose.

The proposed solution of Turbak et al. suffers from several impracticalities and leaves other problems unaddressed. For one, DEF replenishment is controlled by an engine/generator controller that receives information from an engine control module (ECM). These control modules are customized by the OEM of the diesel generator for use with its particular diesel generator set. Thus, the auxiliary DEF supply system lacks independent controls, functions only as a slave to the ECM, and is not designed to interface universally with diesel engines made by other manufacturers. Another problem introduced by this system can occur in the auxiliary DEF hose that carries DEF from the bulk storage tank to the onboard DEF tank. During time periods when the engine is off and no DEF circulates from auxiliary DEF supply system to the onboard DEF tank, the volume of DEF remaining in the DEF hose can be exposed to temperature extremes for long periods of time and this can adversely affect operation. For example, DEF will freeze at about <NUM> degrees F. Should DEF become frozen in the hose, the auxiliary DEF line may clog and cause a system shut-down. At temperatures above <NUM> degrees F, the quality of the DEF will begin to degrade and discolor. Discoloration of DEF can trigger a low-quality alarm, leading to SCR malfunction or system shut-down.

What is needed to support prolonged, unattended operation of diesel engines is an auxiliary DEF system with independent local controls that is capable of interfacing with any make and model of engine and that can operate autonomously to replenish DEF from an auxiliary tank without compromising DEF quality.

<CIT> relates to generator assembly systems and methods of manufacturing and operating generator assembly systems. The generator assembly system includes a generator enclosure, a diesel engine, an after-treatment exhaust system, a primary diesel exhaust fluid system, and an auxiliary diesel exhaust fluid system. The primary diesel exhaust fluid system includes a primary diesel exhaust fluid storage tank fluidly coupled to the aftertreatment exhaust system. The auxiliary diesel exhaust fluid system includes an auxiliary diesel exhaust fluid storage tank, and a transfer pump fluidly coupled to the auxiliary diesel exhaust fluid storage tank. The auxiliary diesel exhaust fluid system is housed in an auxiliary enclosure positioned outside of the generator enclosure. At least one fluid conduit fluidly couples the transfer pump to the primary diesel exhaust fluid storage tank.

<CIT> describes a method for delivering a reductant into a reductant tank through a fill conduit associated with the reductant tank is provided. The reductant tank is in selective fluid communication with an external source having a delivery conduit associated therewith. The method includes connecting the delivery conduit of the external source with the fill conduit of the reductant tank. The method also includes operating a valve provided on the delivery conduit in a first configuration. The method includes changing an operation of the valve from the first configuration to a second configuration. The method also includes purging of a portion of the reductant retained in the fill conduit into the external source through the pump assembly based on the second configuration of the valve.

<CIT> is another reductant fill system in which reductant tank is configured to store a reductant. A receiver is configured to receive a supply of the reductant from an off-board reservoir. A first valve is in communication with the reductant tank and is configured to control a reductant flow into the reductant tank. A reductant supply line is in fluid communication with the receiver. The reductant supply line is configured to provide the reductant flow to the first valve. The reductant level sensor is configured to generate a signal based on a level of reductant in the reductant tank. A controller is communicably coupled to the reductant level sensor. The controller is configured to purge a stranded reductant in the reductant supply line, based on the signal generated by the reductant level sensor.

<CIT> relates to the remote fluid supply for an engine. The system includes a first diesel engine operable to drive a first device, a first DEF tank associated with the first engine and operable to provide DEF to the first diesel engine during operation, a second diesel engine operable to drive a second device, and a second DEF tank associated with the second engine and operable to provide DEF to the second diesel engine during operation. An external DEF tank is arranged to contain a quantity of DEF that is coupled to the first DEF tank and the second DEF tank and operable to selectively deliver DEF from the external DEF tank to each of the first DEF tank and the second DEF tank.

To address the foregoing problems, the present invention discloses an auxiliary system that automatically supplies DEF to an onboard DEF tank of a diesel engine to enable prolonged unattended operation. A system according to the invention operates autonomously by means of a dedicated local controller that is configured for universal cooperation with ECMs of any make and model of diesel engine. In a first aspect of the invention there is provided an autonomous auxiliary diesel exhaust supply system according to claim <NUM>, with this claimed inventive aspect capable of standing alone from further additional disclosure herein concerning (a) the purge cycle executable by an auxiliary DEF supply system of <FIG>, (b) the monitoring (as reflected in <FIG>) of diesel engine conditions that are capable of triggering a purge cycle, and (c) the process for normal operation of an auxiliary DEF supply system as shown in <FIG> There is disclosed herein a scheme for automatically purging the DEF from an auxiliary DEF supply line under various operating conditions.

In one embodiment, an auxiliary DEF supply system according to the invention includes an auxiliary DEF tank, and an auxiliary DEF supply line configured for fluid communication between the auxiliary DEF tank and an onboard DEF tank of a diesel engine. Also provided are a pump, an air inlet, and a three-way valve. The pump is configured to force fluid (ambient air or DEF) from a pump inlet through the auxiliary DEF supply line. The three-way valve is configured to switch between a first state, which couples the auxiliary DEF tank to the pump inlet, and a second state, which couples the air inlet to the pump inlet. In one configuration of the system, the three-way valve when non-energized remains in the first state.

A system according to the claimed invention includes a controller electrically coupled to the pump and configured to receive a supply signal and to command the pump to start in response to receiving the supply signal. For example, the supply signal may represent low DEF level in the onboard DEF tank. The controller may also be electrically coupled to the three-way valve and configured to receive a purge signal. In response to receiving the purge signal, the controller may command the three-way valve to switch to the second state, and command the pump to stop when a predetermined time period has lapsed after receiving the purge signal. The predetermined time period is designed to be sufficient to allow the pump to displace the DEF in the auxiliary DEF supply line with air. Accordingly, in the second state, the pump will force air into the auxiliary DEF supply line until the supply line is purged of DEF.

The purge signal may be programmed to represent an off state of the diesel engine, a shutdown command for the diesel engine, a high DEF level in the onboard DEF tank, or the occurrence of another operating state or condition. Signals such as the supply and purge signals may be received by the controller of the auxiliary DEF supply system from an ECM of the diesel engine via CAN bus protocol. According to the present disclosure, the controller, in response to receiving the purge signal, may command the three-way valve to switch to the first state after the predetermined time period has lapsed.

A single auxiliary DEF supply system is configured for servicing multiple diesel engines. This system is equipped with multiple component trains, wherein each component train includes a pump, an air inlet, a three-way valve, and an auxiliary DEF supply line - one component train for each engine to be serviced from a common auxiliary DEF tank by a common controller.

According to the present disclosure, the auxiliary DEF supply system includes a controller and a portable enclosure, wherein the controller is configured for communicating via CAN bus protocol, and wherein the portable enclosure contains the controller, the auxiliary DEF tank, the pump, the air inlet, the three-way valve, and at least part of the auxiliary DEF supply line. The enclosure may further include a means for heating or cooling the auxiliary DEF tank.

As disclosed herein, an autonomous auxiliary DEF supply system for supplying DEF to an onboard DEF tank in a diesel engine includes the following components: an auxiliary DEF tank, an auxiliary DEF supply line configured for fluid communication between the auxiliary DEF tank and the onboard DEF tank, a pump configured to force DEF through the auxiliary DEF supply line, and a controller electrically coupled to the pump. The controller is configured to command the pump responsive to DEF level signals received from an engine control module of the diesel engine. In one implementation, the DEF level signals are generated according to CAN bus protocol.

In this described arrangement, the controller is configured to execute a routine encoded in software for calculating onboard DEF tank volume. In one implementation, the routine executable by the controller effects the following steps: receiving a low DEF level signal from the engine control module that indicates a low level of DEF in the onboard DEF tank, running the pump for a single fill cycle selected to deliver to the onboard DEF tank a volume of DEF that is less than a total volume of the onboard DEF tank, receiving an actual DEF level signal from the engine control module that indicates a higher level of DEF in the onboard DEF tank, and calculating the total volume of the onboard DEF tank based on the low level of DEF, the delivered volume of DEF, and the higher level of DEF. In another implementation, the controller may effect an additional step for determining a number of the fill cycles that will deliver a maximum volume of DEF to the onboard DEF tank without exceeding the total volume.

Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. Component parts shown in the drawings are not necessarily to scale, and may be exaggerated to better illustrate the important features of the invention. Dimensions shown are exemplary only. In the drawings, like reference numerals may designate like parts throughout the different views, wherein:.

The following disclosure presents exemplary embodiments for an auxiliary system that automatically supplies DEF to an onboard DEF tank of a diesel engine to enable prolonged unattended operation. A system according to the invention operates autonomously by means of a dedicated local controller that is configured for universal cooperation with ECMs of any make and model of diesel engine.

In addition, the specification discusses a scheme for automatically purging the DEF from an auxiliary DEF supply line under various operating conditions.

Diesel engines, often being stationary apparatus, present the opportunity to engineer an independent, portable system for providing an auxiliary service that is common to a wide variety of engines. While modem diesel engines, e.g. those that satisfy Tier <NUM> and Tier <NUM> Final emission control standards, are equipped with ECMs that may be individually modified to effect the control schemes disclosed herein, the variation in ECM functionality among diesel engine makes and models renders the ECM undesirable for use as a controller in a universal auxiliary DEF supply system. It is therefore an objective of the present invention to provide an independent controller for the auxiliary system that interfaces physically and functionally with features that all modem diesel engine control systems have in common. In particular, diesel engines qualified to the Tier <NUM> Final (and certain other) emissions control standard all utilize the CAN bus protocol to command the SCR system. CAN bus signals are used, for example, to monitor DEF parameters, to effect DEF level control and injection, and to satisfy EPA mandates for shutting down the engine via the ECM in response to sensing low DEF levels or low DEF quality. An auxiliary DEF supply system according to the invention exploits common features of diesel engine systems by providing an independent controller capable of executing specialized software instructions that interface with any ECM via known signal protocol to supply DEF from an auxiliary tank when needed to support prolonged periods of operation. By reading certain signals from an ECM in this manner, the auxiliary DEF supply system can sense conditions such as low DEF, and in response turn on an auxiliary DEF pump, fill an onboard DEF tank from an auxiliary DEF tank, and then shut down the pump and purge the supply line. A further objective of the invention is to provide this functionality to multiple diesel generators served from a single auxiliary DEF supply system.

<FIG> shows a block diagram of one embodiment of an auxiliary DEF supply system <NUM> according to the invention, coupled to a diesel engine generator set <NUM>. In the diagram, dashed lines indicate electrical connections for power and control signals, while solid lines indicate mechanical structure or coupling. In this embodiment, the auxiliary DEF supply system <NUM> includes an auxiliary DEF tank <NUM>, an auxiliary DEF supply line <NUM>, a pump <NUM>, and air inlet <NUM>, and a three-way valve <NUM>. Auxiliary DEF tank <NUM> is shown partially filled with a quantity of DEF <NUM>. Tank <NUM> may be of stainless steel or thermoplastic construction, and have a capacity of about <NUM> litres (<NUM> gallons).

A microprocessor controller <NUM> is mounted locally on system <NUM>, and is electrically coupled to control actuation of pump <NUM>, valve <NUM>, and an optional cooling means <NUM>. A Parker model MC42 may be used as microprocessor controller <NUM>. The cooling means <NUM> may be a fluid chiller unit or electric fan configured to cool the auxiliary DEF tank <NUM> and its contents, e.g. in a conventional manner in response to high temperature sensed by a temperature sensor (not shown). A heating means <NUM> may be a heating element or an insulated blanket with electric heat trace, and may be powered from a source of external AC power coupled to an AC inlet receptacle <NUM> that is mounted to the enclosure <NUM>. A switch or other power connector <NUM> may be provided to allow the external AC power to be conveniently connected to either generator <NUM> or to utility power <NUM>. The heating means <NUM> may also include a hose with an integral heating element. Operation of the heating element <NUM> may be controlled by the controller <NUM> in response to sensing low temperature from the temperature sensor.

According to the present disclosure, the pump <NUM> is configured to force fluid (ambient air <NUM> or DEF <NUM>) from a pump inlet at <NUM> through the auxiliary DEF supply line <NUM>. A Shurflo® model <NUM>-<NUM>-<NUM> diaphragm pump is one example of a pump suitable for this purpose. The three-way valve <NUM> is configured to switch between a first state which couples the auxiliary DEF tank <NUM> to the pump inlet <NUM>, and a second state which couples the air inlet <NUM> to the pump inlet <NUM>. An Assured Automation™ model B33DAXV4F valve is one example of a three-way valve that is suitable for this purpose. In one configuration of the system <NUM>, the three-way valve <NUM> when non-energized remains in the first state, so that during normal operation, as described in greater detail below, the system <NUM> is in a ready condition to pump DEF <NUM> from the auxiliary DEF tank <NUM> through the auxiliary DEF supply line <NUM> to supply or replenish another DEF tank, such as one that is mounted onboard a diesel engine.

System <NUM> is shown in a state of use. In this example, system <NUM> is coupled electrically and mechanically to a diesel engine and generator set (DEG) <NUM>. In other applications, system <NUM> may be coupled to multiple diesel engines, including for example, engine-generators that provide power to different independent loads, or for a paired set of generators powering a common load, or which may be redundant generators providing a source of emergency backup power for a processing plant. In other applications, system <NUM> may be coupled to one or more diesel engines that serve as prime movers for pumps, air compressors, or other non-electrical apparatus.

Diesel engine <NUM> of DEG <NUM> represents a fully assembled apparatus that is commercially available from any of a number of manufacturers such as Cummins®, Ford®, John Deere®, Isuzu®, Volvo®, etc. While such apparatus include hundreds of components, only a few are shown in the figure and these are exaggerated for purposes of illustrating salient features of the present invention. For example, onboard DEF tank <NUM>, DC battery <NUM>, and ECM <NUM> appear as separate components but are typically integral to the system of diesel engine <NUM>. Electrical generator <NUM> of DEG <NUM> also represents a fully assembled apparatus, and may be provided separately from diesel engine <NUM>, or as an integral part of DEG <NUM>.

The auxiliary DEF supply line <NUM> mechanically connects system <NUM> to system <NUM>. Supply line <NUM> is configured to maintain fluid communication between the auxiliary DEF tank <NUM> and the onboard DEF tank <NUM>. Supply line <NUM> may be a <NUM> millimetre (<NUM>/<NUM> inch) inside diameter hose made of a flexible material such as synthetic rubber and having a nominal length of about <NUM> metres (<NUM> feet). Other sizes, lengths, and materials for supply line <NUM> are possible within the scope of the invention. Onboard DEF tank <NUM> provides a source of DEF to diesel engine (DE) <NUM>. The diesel engine <NUM> is mechanically coupled to the electrical generator (G) <NUM>. DC battery <NUM> is electrically coupled to the diesel engine <NUM> in a conventional manner to store energy for purposes of starting the engine, and to be recharged by an alternator when the engine is running. The battery <NUM> may provide electrical power to ECM <NUM>. For signal communications, ECM <NUM> is also electrically coupled to the engine <NUM> and to a dosing control unit (DCET) <NUM>. The DCET <NUM> is an OEM device that controls injection of DEF into the exhaust system of the diesel engine <NUM> in response to receiving data representing certain conditions as described herein, such as the engine <NUM> running. DCET <NUM> is electrically coupled to a DEF sensor <NUM> installed within the onboard DEF tank <NUM>. The DEF sensor <NUM> is configured to sense DEF level or DEF quality (or both) in the onboard DEF tank <NUM>. Generally, the DCET <NUM> receives CAN data from DEF tank <NUM> via a private CAN bus <NUM> and relays that information to the ECM <NUM> via public CAN bus <NUM>. Signals transmitted to or from DCET <NUM> may govern purging of the DEF lines <NUM> after the engine <NUM> is stopped.

Onboard DEF tank <NUM> may be a single tank 32a or 32b, or for purposes of illustration it may represent multiple DEF tanks that are configured in fluid communication, such as DEF tank 32a and DEF tank 32b connected together by an equalizing line <NUM>. DEF tank 32a represents a tank style common in certain diesel engine models that has an upper port <NUM> at the top of the tank. DEF tank 32b represents a tank style common in certain other diesel engine models that has a port <NUM> at the bottom of the tank. These ports, however, may already be plumbed for other purposes, such as injecting the DEF into the SCR system. Connecting auxiliary DEF supply line <NUM> to the onboard DEF tank <NUM> may require a modification to allow for coupling of the auxiliary DEF supply line <NUM>. But the onboard DEF tank, being an essential component in an environmentally qualified SCR system, cannot normally be modified without disqualifying the system configuration. An auxiliary system according to the present disclosure must therefore connect via an auxiliary fill cap port <NUM> or an existing port - either through a port <NUM> or a port <NUM> - that is not already dedicated for another purpose. In some cases, where onboard DEF tank <NUM> comprises multiple tanks 32a and 32b in fluid communication, one of the ports <NUM> may be rendered redundant and not used. In that case, the auxiliary DEF supply line <NUM> may take the path of supply line 14a and connect to a port <NUM>. In other cases, where the port <NUM> merely serves as a drain plug for maintenance purposes, the auxiliary DEF supply line <NUM> may take the path of supply line 14b and connect to the port <NUM>. In other cases, the auxiliary DEF supply line <NUM> may take the path of supply line 14c and connect to an auxiliary fill cap with port <NUM>. Note that the three possible paths, 14a, 14b and l4c, for the auxiliary DEF supply line <NUM> are alternative paths that are superimposed in <FIG> for purposes of illustration only. An auxiliary DEF supply system according to the invention needs only one such supply line to the onboard DEF tank. At or near the end of supply line l4b, an optional check valve <NUM> may be installed, as shown, to prevent backflow of DEF due to hydrostatic pressure. A Fegris® <NUM> model valve may be used as check valve <NUM>.

System <NUM> and system <NUM> are electrically connected between the controller <NUM> and ECM <NUM>. According to the present disclosure, controller <NUM>, and other components of system <NUM> electrically coupled to controller <NUM>, may receive DC power via the connection to ECM <NUM>. The controller <NUM> and the other system <NUM> components may be powered by direct connection to generator <NUM>. On a signal level, electrical coupling between controller <NUM> and ECM <NUM> allows controller <NUM> to read or receive control signals transmitted by ECM <NUM> that are commonly required in any diesel engine system that is qualified to the environmental standards referenced herein. Such signals include DEF level and DEF quality in the onboard DEF tank <NUM>. Controller <NUM> may also read any other signal generated by ECM <NUM>, such as the state of an engine ignition switch, the running state of the engine <NUM> (on or off), the voltage output of battery <NUM>, and an engine fault signal. In response to receiving ECM signals, the controller <NUM> may be programmed to generate one or more actuation signals to pump <NUM> or to valve <NUM> to supply DEF <NUM> to the onboard DEF tank <NUM> or to purge DEF <NUM> from the auxiliary DEF supply line <NUM>. For example, the controller <NUM> may be programmed to monitor the ECM <NUM> for certain CAN bus signals known to represent DEF level in the onboard DEF tank <NUM>. John Deere® and Cummins® ECMs are known to broadcast DEF level using the standard J1939 SAE PGN <NUM> (FE5 Hex). Isuzu® ECMs, however, are known to broadcast DEF level using a proprietary PGN <NUM> (FFE8 Hex). According to the invention, controller <NUM> may be programmed to monitor the ECM first for 0xFE56, and if no data is detected after a timeout period has lapsed, begin monitoring instead for 0xFFE8 as a source for the DEF level data. In this manner, controller <NUM> may be programmed to read CAN bus signals that use different message formats to communicate similar data.

A telematics (TM) device <NUM> may be configured to receive CAN data via public CAN bus <NUM> to enable one form of remote monitoring of system <NUM>. TM <NUM> received the CAN data and broadcasts relevant information wirelessly, e.g. using cellular protocol, based on the telematics programming and end user needs.

According to the foregoing system configuration, an auxiliary DEF supply system <NUM> through its controller <NUM> may read a low DEF signal broadcast by ECM <NUM>, and interpret the data received as a "supply" signal, i.e. a signal indicating that the onboard DEF tank <NUM> needs to be replenished with DEF <NUM> from the auxiliary DEF tank <NUM>. In response to receiving the supply signal, the controller <NUM> according to its programming issues a command signal to the pump <NUM> to start. The start command may be effected according to well-known control techniques, such as controller <NUM> changing voltage at an output pin from low to high to cause a power relay to change state and energize the terminals of the pump. With the three-way valve <NUM> in the first state, pump <NUM> delivers DEF <NUM> to the onboard DEF tank <NUM> via the supply line <NUM> to replenish the onboard volume of DEF.

The controller <NUM> may be electrically coupled in similar fashion for actuating the three-way valve <NUM>. Other data read from the ECM by the controller, such as a high DEF signal, may be interpreted as a "purge" signal, i.e. a signal indicating that the onboard DEF tank <NUM> is full, and that the auxiliary DEF supply line <NUM> must be purged of residual DEF. In response to receiving the purge signal, the controller <NUM> may command the three-way valve <NUM> to switch to the second state, and command the pump <NUM> to stop when a predetermined time period has lapsed after receiving the purge signal. The predetermined time period should be sufficient to allow the pump <NUM> to displace the DEF in the auxiliary DEF supply line <NUM> with ambient air <NUM>. Accordingly, in the second state, the pump <NUM> will force air into the auxiliary DEF supply line <NUM> until the supply line is purged of DEF. The controller <NUM>, in response to receiving a purge signal, may command the valve <NUM> to switch to the first state after the predetermined time period has lapsed. According to the present disclosure, the purge signal may represent an off state of the diesel engine <NUM>, a shutdown command for the diesel engine <NUM>, a high DEF level in the onboard DEF tank, or the occurrence of some other operating state or condition that warrants evacuation of DEF from the supply line <NUM>.

According to the present disclosure, the auxiliary DEF supply system <NUM> includes a controller <NUM> and a portable enclosure <NUM>, wherein the controller <NUM> is configured as previously disclosed, and wherein the portable enclosure <NUM> contains the controller <NUM>, the auxiliary DEF tank <NUM>, the pump <NUM>, the air inlet <NUM>, the three-way valve <NUM>, and at least part of the auxiliary DEF supply line <NUM>. The portable enclosure <NUM> may further include a heating means <NUM>, such as an insulated blanket with electric heat trace. The portable enclosure <NUM> may further include a cooling means <NUM>, such as fluid chilling unit or fan, for cooling the auxiliary DEF tank <NUM>. The system <NUM> is configured for autonomous, unattended operation by programming the controller <NUM> for normal operation (described below) in which the controller continuously monitors ECM signals for low and high DEF levels, and in response, automatically cycles system <NUM> through supply and purge cycles. Barring any operating anomalies, such as engine faults or other component failures, system <NUM> can automatically replenish one or more systems <NUM> with DEF <NUM> until tank <NUM> is depleted of DEF or until the diesel engines run out of fuel. A level sensor (not shown) may be installed in auxiliary DEF tank <NUM> to monitor the level of DEF <NUM> and transmit a level signal to the controller <NUM>. Controller <NUM> may broadcast the DEF tank <NUM> level signal via public CAN Bus <NUM>, to provide an operator located remotely from system <NUM> with the ability to monitor the state of the system. Other system conditions known to controller <NUM>, such as onboard DEF tank level, running state of the diesel engine, fault signals output by the ECM, number of purge cycles run, etc. can be similarly transmitted via the public CAN Bus <NUM>. Any of the signals transmitted by the ECM via the public CAN Bus <NUM> can also be output via Ethernet port <NUM> to a remote operator monitoring auxiliary system operation, or to a local PC that provides an operator interface for programming, setpoint adjustment, and system diagnostics.

According to the present disclosure, a single auxiliary DEF supply system <NUM> is configured for servicing multiple diesel engines <NUM> or DEGs <NUM>. This system is equipped with multiple component trains, wherein each component train includes a pump <NUM>, an air inlet <NUM>, a three-way valve <NUM>, and an auxiliary DEF supply line <NUM> - i.e., one component train for each engine to be serviced from a common auxiliary DEF tank <NUM> by a common controller <NUM>. The controller <NUM> is able to service, simultaneously and independently, diesel engines of different makes and models, wherein each engine is served in the same manner as described above as if it were the only engine coupled to the auxiliary DEF supply system.

<FIG> shows a flow chart of a process for a validation routine <NUM> executable by an auxiliary DEF supply system <NUM> as described in the foregoing paragraphs. Validation routine <NUM> may be performed upon first coupling system <NUM> to a diesel engine system <NUM> to allow for automatic determination of the volume of the onboard DEF tank <NUM>. Once the volume is known, the system <NUM> can store in the memory of controller <NUM> data representing a number of "fill cycles" that are required for the pump <NUM> to deliver DEF <NUM> sufficient to fill the onboard DEF tank <NUM>. A fill cycle is a time period, selected with knowledge of the flow rate of pump <NUM>, during which the pump <NUM> will deliver enough DEF <NUM> to allow for detection of an acceptable rise in onboard DEF tank volume, but not so much DEF <NUM> as to overflow the smallest known volume of onboard DEF tank (e.g. <NUM> gal. ) likely to be serviced by system <NUM>. The validation routine gives system <NUM> the flexibility to interface universally with any make or model of diesel engine by adjusting the number of fill cycles required to fill any size of onboard DEF tank. The system <NUM> can therefore predict when the onboard DEF tank will become full, and initialize a purge cycle at that point in time, without being reliant on the accuracy of high DEF level signals received from ECM <NUM>.

Validation routine <NUM> may be stored in software executable by the controller <NUM>. The flow chart illustrates the salient steps of the routine. Validation routine <NUM> begins at step <NUM>, at which controller <NUM> receives a low DEF level signal from ECM <NUM> that indicates a low level of DEF (usually <NUM>% of capacity) in the onboard DEF tank <NUM>. In response, in the next step <NUM>, the controller <NUM> runs the pump <NUM> for one fill cycle to deliver to the onboard DEF tank a volume of DEF that is less than a total volume of the onboard DEF tank. The volume of DEF delivered during the fill cycle is less than or equal to about <NUM>% of tank capacity. For example, given a pump flow rate of <NUM> litres (1gpm), and a minimum onboard DEF tank volume of <NUM> litres (<NUM> gallons), the fill cycle time may be set to <NUM> seconds. This fill cycle will deliver about <NUM> litres (<NUM> gallons) of DEF (or <NUM>% of capacity) into the tank, bringing the total volume up to about <NUM>%, which coincides with the typical setpoint for triggering a high level DEF signal. In the next step <NUM>, the controller <NUM> may stop the pump <NUM> for the duration of a predetermined stabilization delay, to allow DEF tank volume to stabilize in case DEF tank <NUM> consists of multiple tanks (e.g. 32a, 32b) in fluid communication. In the next step <NUM>, the controller <NUM> reads the measured level of DEF tank <NUM> as received from ECM <NUM>, and determines whether the measured level has reached a minimum validation point, e.g. <NUM>% of tank capacity. If it has, the process proceeds to step <NUM>. At step <NUM>, the controller <NUM> calculates the total volume of the onboard DEF tank based on the low level of DEF, the delivered volume of DEF, and the higher (or measured) level of DEF. In a final step <NUM>, the controller determines a number of fill cycles required to deliver a maximum volume of DEF to the onboard DEF tank without exceeding the total volume, and stores the number in memory.

If, however, in step <NUM> the controller <NUM> determines that the measured level has failed to reach the validation point, e.g. <NUM>% of tank capacity has not been reached, the process advances to step <NUM>, in which an alarm is generated. The alarm may consist of illumination of an FED, generation of an audible tone, and/or broadcasting the failed attempt via public CAN Bus <NUM>, e.g. J1939 CAN Bus. At the next step <NUM>, the controller decides whether a maximum number of failed validation attempts has occurred, by comparing accumulated failures to a threshold value, e.g. three. If the maximum threshold has not been reached, the process loops back to step <NUM> to initiate another fill cycle. If, however, at step <NUM> the maximum threshold has been reached, the process logs a validation failure at step <NUM>, and no further fill cycles are performed. A validation failure may indicate a problem or defect in the system, such as a leak, a clogged line, or a component failure. Once a validation failure is logged, the process may run a purge cycle, as in step <NUM> below.

Alternatively, if at step <NUM> the maximum threshold for fill failures is reached, a fault light illuminates for the first time and refill routines for DEF tank <NUM> are locked out for the duration of the engine run period. If the engine <NUM> stops and is later started again, system <NUM> will reset the previous fault and restart its normal routines. To illustrate further, if for example the maximum number of fill failures is set at three: if a first fill failure occurs at step <NUM>, an internal fault is generated and broadcast via public CAN bus <NUM>, but the LED alarm is not illuminated. Later if a second fill failure occurs at step <NUM>, a second alarm is similarly broadcast, but the LED alarm is still not illuminated. Upon occurrence of a third fill failure at step <NUM>, a third alarm is broadcast and the LED alarm illuminates to indicate that the system <NUM> will no longer attempt to fill during that particular run cycle. In this case, a local operator cognizant of the alarm can troubleshoot the system, and a subsequent stopping and restarting of engine <NUM> will clear the alarm and enable normal operation.

In accordance with the present disclosure, in lieu of, or prior to conducting a validation routine, controller <NUM> may execute a different routine that first determines the make or model (or both) of engine <NUM>. This may be accomplished by issuing a query to ECM <NUM> via public CAN Bus <NUM>, to read data indicative of engine make and model. Alternatively, the make and model may be manually entered by an operator, for example, via port <NUM> by selecting from a menu of choices that each represent a particular make and model, or class, of engine. The routine can then match the particular engine make, model, and/or class to a known volume that corresponds to the onboard DEF tank of that particular engine, e.g. by consulting a lookup table.

<FIG> shows a flow chart of a process <NUM> for normal operation of an auxiliary DEF supply system <NUM> as described in the foregoing paragraphs. Normal operation is a condition in which system <NUM> runs automatically without faults or errors and periodically delivers auxiliary supplies of DEF <NUM> to replenish an onboard DEF tank <NUM> of a diesel engine system <NUM> that is also running without experiencing faults or errors that would cause a system malfunction.

During normal operation of system <NUM>, in decision step <NUM> the controller <NUM> periodically reads signals from ECM <NUM> indicative of whether the diesel engine <NUM> is running. If the engine is not running, the process advances to step <NUM> in which controller <NUM> maintains the pump <NUM> in a stopped or deenergized condition. From step <NUM> the process will periodically loop back to decision step <NUM> to assess whether there has been any change in the state of the diesel engine. If the diesel engine is running, the process advances to decision step <NUM> to determine whether a low level DEF signal is being broadcast from ECM <NUM>. If not, then the controller again maintains the pump <NUM> in a deenergized condition at step <NUM> and the process loops again to step <NUM>, to periodically monitoring engine state, and possibly again to step <NUM> to monitor DEF level in the onboard DEF tank <NUM>.

If the controller <NUM> reads a low level DEF signal at step <NUM>, the process advances to step <NUM>. At this stage the controller <NUM> energizes pump <NUM> for the duration of a single fill cycle, to pump a minimum volume of DEF <NUM> into the onboard DEF tank <NUM>. Next, at step <NUM>, the controller <NUM> stops the pump for the duration of a stabilization delay, to allow DEF level in the onboard DEF tank <NUM> to stabilize. Next, at decision step <NUM>, the controller reads data from ECM <NUM> to determine whether a high level DEF signal is being broadcast. If not, the process advances to step <NUM>, to determine whether a maximum number of fill cycles has been reached. If not, the process loops back to step <NUM> for another fill cycle. If, however, the controller <NUM> at step <NUM> determines that a maximum number of fill cycles has been reached, the process advances to step <NUM> to run a purge cycle. If, at step <NUM>, the controller reads a high level DEF signal, then the process advances to step <NUM> to run a purge cycle.

<FIG> shows a flow chart of a purge cycle <NUM> executable by an auxiliary DEF supply system <NUM> as described in the foregoing paragraphs. The controller <NUM>, upon receiving an indication of a system condition requiring a purge of auxiliary DEF supply line <NUM>, such as the onboard DEF tank <NUM> becoming full as in event <NUM> in process <NUM>, may execute all or a portion of the steps of purge cycle <NUM>. The purge cycle begins at step <NUM>, in which the controller <NUM> stops, or deenergizes the pump <NUM>. Next, at step <NUM>, the controller <NUM> switches the three-way valve <NUM> to its second state wherein ambient air is presented at pump inlet <NUM>. The next step <NUM> is an optional step, in which a time delay, e.g. one second, is enforced by the controller <NUM> to ensure actuation of valve <NUM> before actuation of pump <NUM>. Next, at step <NUM>, the controller <NUM> energizes the pump <NUM> for a predetermined, programmable run-time period, e.g. <NUM> seconds, to ensure that all residual DEF <NUM> is forced out of the auxiliary DEF supply line <NUM> and into the onboard DEF tank <NUM>. The final step <NUM> occurs at the end of the run-time period. In step <NUM>, the controller <NUM> stops the pump <NUM> and deenergizes valve <NUM> so that it reverts to the first state.

Claim 1:
An autonomous auxiliary diesel exhaust fluid "DEF" supply system (<NUM>) for supplying DEF to an onboard DEF tank (<NUM>) in a diesel engine (<NUM>), comprising:
an auxiliary DEF tank (<NUM>);
an auxiliary DEF supply line (<NUM>) configured for fluid communication between the auxiliary DEF tank (<NUM>) and the onboard DEF tank (<NUM>);
a pump (<NUM>) configured to force DEF (<NUM>) through the auxiliary DEF supply line; and
a controller (<NUM>) electrically coupled to the pump (<NUM>);
wherein the controller (<NUM>) is configured to command the pump responsive to DEF level signals received from an engine control module (<NUM>) of the diesel engine (<NUM>);
characterized in that:
the controller (<NUM>) is configured to execute a routine (<NUM>) encoded in software for calculating (<NUM>) onboard DEF tank volume; and
wherein the routine executed by the controller (<NUM>) comprises:
receiving (<NUM>) a low DEF level signal from the engine control module that indicates a low level of DEF in the onboard DEF tank;
running (<NUM>) the pump (<NUM>) for a preset period of time representing a single fill cycle selected to deliver to the onboard DEF tank (<NUM>) a volume of DEF that is less than a total volume of the onboard DEF tank;
receiving an actual DEF level signal from the engine control module (<NUM>) that indicates a higher level of DEF in the onboard DEF tank (<NUM>);
calculating (<NUM>) the total volume of the onboard DEF tank based on the low level of DEF, the delivered volume of DEF, and the higher level of DEF; and
running a subsequent number of fill cycles to deliver the maximum volume of DEF to the onboard DEF tank without exceeding the total volume.