U.S. patent application number 13/777900 was filed with the patent office on 2014-08-28 for engine-generator with load bank and control system.
This patent application is currently assigned to MULTIQUIP, INC.. The applicant listed for this patent is MULTIQUIP, INC.. Invention is credited to George Fell.
Application Number | 20140239921 13/777900 |
Document ID | / |
Family ID | 51358538 |
Filed Date | 2014-08-28 |
United States Patent
Application |
20140239921 |
Kind Code |
A1 |
Fell; George |
August 28, 2014 |
ENGINE-GENERATOR WITH LOAD BANK AND CONTROL SYSTEM
Abstract
A load bank comprises one or more load resistors connected to an
engine-generator and a control system for maintaining a minimum
generator load when necessary for optimal operation. The control
system operates the load bank to mitigate harmful effects of
generator neglect and maintains loading for efficient DPF
regeneration while allowing the generator to quickly dump the load
bank when real load increases.
Inventors: |
Fell; George; (Carson,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MULTIQUIP, INC.; |
|
|
US |
|
|
Assignee: |
MULTIQUIP, INC.
Carson
CA
|
Family ID: |
51358538 |
Appl. No.: |
13/777900 |
Filed: |
February 26, 2013 |
Current U.S.
Class: |
322/21 ;
290/7 |
Current CPC
Class: |
H02P 9/006 20130101 |
Class at
Publication: |
322/21 ;
290/7 |
International
Class: |
H02P 9/00 20060101
H02P009/00 |
Claims
1. An engine-generator and load bank system comprising: an engine
mechanically connected to and capable of driving an alternator;
said engine having an engine control module and a particulate
filter; said alternator in electrical communication with an output
bus and a load bank bus; at least one load monitoring device in
electrical communication with said output and load bank buses; a
generator controller comprising a load dump output and a load
enable output, said generator controller in electrical
communication with said engine control module; a load bank
controller comprising a load enable input, a load dump input, a
load sensor, and at least one load step output; said load dump
output in electrical communication with said load dump input; said
load enable output in electrical communication with said load
enable input; said load monitoring device in electrical
communication with said load sensor; at least one load step
contactor in electrical communication with said at least one load
step output; and at least one load step resistor in electrical
communication with said load bank bus by way of said at least one
load step contactor; wherein said generator controller provides a
control signal via said load enable output in at least one of the
following cases: neglect and regeneration; and wherein said
generator controller provides a control signal via said load dump
output in case of a load spike.
2. The engine-generator and load bank system of claim 1 wherein the
generator controller is further configured with excessive idle
control.
3. The engine-generator and load bank system of claim 1 comprising
one load step resistor.
4. The engine-generator and load bank system of claim 1 comprising
a plurality of load step resistors.
5. The engine-generator and load bank system of claim 1 which
further comprises a remote communication module and antenna.
6. The engine-generator and load bank system of claim 5 wherein the
remote communications module communicates via satellite.
7. The engine-generator and load bank system of claim 5 wherein the
remote communications module communicates via a terrestrial
wireless network.
8. The engine-generator and load bank system of claim 1 wherein the
engine is a diesel engine.
9. The engine-generator and load bank system of claim 1 wherein the
engine is a Tier IV Interim or newer diesel engine.
10. The engine-generator and load bank system of claim 1 wherein
said alternator, output bus, load bank bus, and at least one load
step resistor comprise a poly-phase electrical system.
11. The engine-generator and load bank system of claim 1 wherein
said alternator, output bus, load bank bus, and at least one load
step resistor comprise a three-phase electrical system.
12. The engine-generator and load bank system of claim 1 which
further comprises a common base and enclosure.
13. The engine-generator and load bank system of claim 1 wherein
said at least one load step resistor is physically located in an
enclosure connected to the radiator of said engine.
14. The engine-generator and load bank system of claim 1 wherein
said at least one load step resistor is located remotely from said
engine-generator.
15. The engine-generator and load bank system of claim 1 wherein
the generator controller and engine control module are configured
to communicate via SAE J1939 protocol.
16. The engine-generator and load bank system of claim 1 wherein
the generator controller is configured to provide said control
signal to said load dump output within 10 seconds.
17. The engine-generator and load bank system of claim 1 wherein
the generator controller is configured to provide said control
signal to said load dump output within 1 second.
18. The engine-generator and load bank system of claim 1 wherein
the generator controller is configured to provide said control
signal to said load dump output within 0.1 second.
19. An engine-generator and load bank system comprising: an engine
mechanically connected to and capable of driving an alternator;
said engine having an engine control module and a particulate
filter; said alternator in electrical communication with an output
bus and a load bank bus; a generator controller in electrical
communication with said engine control module, said generator
controller having at least one load step output; at least one load
step contactor in electrical communication with said at least one
load step output; and at least one load step resistor in electrical
communication with said load bank bus by way of said at least one
load step contactor; wherein said generator controller is capable
of operating said load step contactor to connect said load step
resistor in at least one of the following cases: neglect and
regeneration; and wherein said generator controller is capable of
operating said load step contactor to disconnect said load step
resistor in case of a load spike.
20. The engine-generator and load bank system of claim 19 wherein
the generator controller is further configured with excessive idle
control.
21. The engine-generator and load bank system of claim 19
comprising one load step resistor.
22. The engine-generator and load bank system of claim 19
comprising a plurality of load step resistors.
23. The engine-generator and load bank system of claim 19 which
further comprises a remote communication module and antenna.
24. The engine-generator and load bank system of claim 23 wherein
the remote communications module communicates via satellite.
25. The engine-generator and load bank system of claim 23 wherein
the remote communications module communicates via a terrestrial
wireless network.
26. The engine-generator and load bank system of claim 19 wherein
the engine is a diesel engine.
27. The engine-generator and load bank system of claim 19 wherein
the engine is a Tier IV Interim or newer diesel engine.
28. The engine-generator and load bank system of claim 19 wherein
said alternator, output bus, load bank bus, and at least one load
step resistor comprise a poly-phase electrical system.
29. The engine-generator and load bank system of claim 19 wherein
said alternator, output bus, load bank bus, and at least one load
step resistor comprise a three-phase electrical system.
30. The engine-generator and load bank system of claim 19 which
further comprises a common base and enclosure.
31. The engine-generator and load bank system of claim 19 wherein
said at least one load step resistor is physically located in an
enclosure connected to the radiator of said engine.
32. The engine-generator and load bank system of claim 19 wherein
said at least one load step resistor is located remotely from said
engine-generator.
33. The engine-generator and load bank system of claim 19 wherein
the generator controller and engine control module are configured
to communicate via SAE J1939 protocol.
34. The engine-generator and load bank system of claim 19 wherein
the generator controller is configured to operate said load step
contactor to disconnect said load step resistor within 10
seconds.
35. The engine-generator and load bank system of claim 19 wherein
the generator controller is configured to operate said load step
contactor to disconnect said load step resistor within 1
seconds.
36. The engine-generator and load bank system of claim 19 wherein
the generator controller is configured to operate said load step
contactor to disconnect said load step resistor within 0.1
seconds.
37. A method for operating an engine-generator and load bank system
with a generator controller and an engine control module, the
generator controller configured with logic and hardware to control
the load bank, the method comprising the following steps: a.
setting a rated operating load; b. setting a load window bounded by
a low load and an upper load in said generator controller; c.
setting a duration in said generator controller; d. setting a
minimum acceptable load corresponding to optimal engine exhaust
temperature for regeneration; e. monitoring connected load of said
engine-generator; f. monitoring regeneration of said
engine-generator with said engine control module; g. activating
said load bank if said generator operates in a neglect scenario as
defined by said window and said duration; h. activating said load
bank if said connected load is less than said minimum acceptable
load and said engine-generator initiates regeneration; and i.
dumping said load bank if a load spike is detected.
38. The method of claim 37 that further comprises the steps of: a.
setting an maximum idle time; b. monitoring idle time of said
engine control module; and c. initiating a load cycle if said idle
time corresponds to maximum idle time.
Description
TECHNICAL FIELD
[0001] The disclosed embodiments relate generally to systems of
engine-generators with load banks.
BACKGROUND
[0002] Electric generators, particularly portable engine-generator
units, are often operated under variable load conditions. Such
portable units are also often left unattended, which further causes
them to be operated in sub-optimal conditions. It is well known
that operating engine-generators under fluctuating load conditions
can present a number of problems. As explained in U.S. Pat. No.
3,530,300 to Gunther, et al., diesel-fueled engine-generators are
especially susceptible to problems associated with light-load
conditions. In particular, a lightly loaded, diesel-fueled
engine-generator may cause the engine portion of the machine to
operate such that fuel within the engine remains unburned. This
unburned fuel forms tar or carbon deposits, or both, which can
collect within various parts of the engine, including exhaust
pipes. This condition has historically been referred to as "wet
stacking."
[0003] Diesel engines also create soot during their combustion
process. When an engine is operating under lightly load conditions,
it tends to create more soot. Historically, the soot was exhausted
from the engine to the atmosphere via exhaust pipes. More recently,
however, increasing concern about, and regulation of particulate
emissions has lead to changes in the manner in which diesel engines
may legally operate. Modern diesel engines, including so-called
Tier IV Interim and newer engines, are equipped with particulate
filters that serve to capture and remove soot from engine exhaust.
The problem is that these particulate filters, which are also
called diesel engine particulate filters or DPF, tend to clog with
the particulate that they filter. Those clogs inhibit engine
exhaust, which may significantly or entirely decrease the
operability of an engine. To combat this DPF-clogging issue, modern
diesel engines are often equipped with a "regeneration" feature.
Regeneration involves a process in which the engine doses a DPF
with diesel and then ignites that diesel to burn-off accumulated
soot. The soot is reduced to ash, which falls away from the DPF,
thus clearing the DPF and the engine exhaust system.
[0004] Complicating DPF regeneration in engine-generator
applications is the effect of generator loading on engine
performance. Engine exhaust temperature is proportional to
generator loading. Thus, a lightly loaded generator causes the
engine to operate with lower exhaust temperature than a generator
operating under greater loading conditions. The problem is that
regeneration efficiency is inversely proportional to exhaust
temperature. That is, regeneration works better when an engine is
operating with higher exhaust temperatures. So, in engine-generator
applications, regeneration is more efficient when a generator is
operating under loaded conditions.
[0005] It is known in the art that wet stacking may be mitigated by
connecting to the generator a "dummy" load in parallel with the
actual, or "real," load. Such dummy loads often comprise banks of
resistors that may be switched in steps, often automatically, in
inverse proportion to the real load. In this way, a generator may
be connected so that it always experiences some minimum demand. As
Gunther, et al. explains, this is represented by the equation
P.sub.G=P.sub.RL+P.sub.DL, where P.sub.G is the total generator
demand, P.sub.RL is the demand of the real load, and P.sub.DL is
the demand of the dummy load. This same method of operation helps
reduce soot in the engine.
[0006] But despite the benefits of the system of Gunther, et al.,
and other similar configurations, such schemes tend to be wasteful
because they cause the engine portion of the engine-generator to
burn a set amount of fuel, at all times, in order to maintain
P.sub.G. This is because the engine must burn more fuel to maintain
an increased generator output. So while the system is burning
cleaner, it uses more fuel than necessary. In a world of rapidly
decreasing oil supplies, and rapidly increasing fuel costs, it is
desirable to balance the benefits of minimum generator loading with
economic realities. Said differently, it is advantageous to
decrease soot production and wet-stacking events with dummy loads
(aka load banks), while at the same time being mindful of the fuel
costs associated with operating dummy loads. Furthermore, load
banks have not previously been employed to aid with DPF
regeneration.
SUMMARY OF THE DISCLOSURE
[0007] Disclosed here is a load bank that provides a dummy load to
an electric generator, which allows an engine-generator unit to
more efficiently operate by decreasing the frequency of
regeneration cycles an engine must initiate, and, when regeneration
occurs, ensures a minimum generator load to raise exhaust
temperatures and thus increase regeneration efficiency.
[0008] In accordance with some embodiments of the disclosed
technology, an engine-generator and load bank system comprises a
plurality of load resistors and load step contactors for engaging
the load resistors. The plurality of load resistors are configured
to allow for variability, or "stepping," of the total resistance of
the dummy load. In other words, when the load bank is engaged, or
connected, the load bank is configured to add or remove load
resistors in steps, as required by system parameters. The disclosed
technology is operable to entirely disconnect, or "dump," the load
bank from the generator within a specified time, which may be
necessary when the real load of the generator rapidly
increases.
[0009] In accordance with some embodiments of the disclosed
technology, the system is equipped with a generator controller and
a load bank controller, which could be physically combined, that
are configured to monitor both the engine side and the generator
load of an engine-generator and to operate the load bank. In
according with some embodiments, the system is equipped with a
single controller that is configured to monitor the engine side of
an engine-generator and to operate the load bank.
[0010] In accordance with some embodiments of the disclosed
technology, the generator and load bank controllers are configured
to initiate the load bank when certain conditions exist. The load
bank is initiated when there is a "neglect scenario" or "neglect
case." The generator controller, via the load bank controller,
monitors the load connected to the generator to ensure that the
load is within a "window" or "load window" bounded by pre-set lower
and upper load levels. If the load connected to the generator
remains at or below some pre-set load condition--i.e., below the
window--for a pre-set duration, the generator controller signals
the load bank controller to initiate the load bank. The load bank
controller then increases or decreases the total resistance of the
load bank by connecting or disconnecting load step resistors as
necessary to maintain the load within window. If the load rises
above the window, the steps of the load bank are disconnected as
necessary. In this way, the total load on the generator--i.e., the
real load and the resistance of the load bank--remains within
pre-set limits. The pre-set load corresponds to a power demand on
the generator that provides for optimal operation, which minimizes
wet stacking and soot build up.
[0011] Restricting the load bank to operation in a neglect case
allows one to save fuel because the load bank will only draw power
from the generator when necessary to prevent wet stacking and soot
build up. The generator will thus be allowed to operate in a
sub-optimal state until such time as wet stacking and soot build up
are likely to occur. The load window and duration variables
necessary for determining a neglect scenario will thus be based on
manufacturer or user-defined values directed at pinpointing the
time when wet stacking and soot build up is likely to begin.
[0012] In accordance with some embodiments of the disclosed
technology, the duration variable for neglect is cumulative. The
generator controller will constantly monitor load levels and will
track the time period for which load levels are below the window.
If the cumulative time the system is operated below the window
reaches the pre-set duration, the generator controller signals the
load bank controller to initiate the load bank. This cumulative
timing of sub-optimal operation occurs even the system is operated
for short periods of time at load levels within and above the
window. If, however, the system operates for a pre-set time within
the window, a neglect scenario may be avoided. The system thus
accounts for the cumulative nature of soot build up in the engine.
The problems associated with this soot accumulation can be avoided
if the engine is operated under loaded conditions for a
pre-determined duration. The generator controller therefore ensures
the system is operated under a designated load for a pre-set
duration. This operation for a pre-set duration under set load
conditions at full engine speed is disclosed here a "load
cycle."
[0013] In accordance with some embodiments of the disclosed
technology, the generator controller is configured to signal the
load bank controller to initiate the load bank when the engine
control module initiates regeneration to clean the DPF. In such a
"regeneration scenario" or "regeneration case," as it is referred
to here, the generator controller will signal the load bank
controller to initiate the load bank, thus providing a minimum load
for the system in order to maintain an engine exhaust temperature
necessary for the DPF regeneration to effectively clean the
DPF.
[0014] In accordance with some embodiments of the disclosed
technology, the generator controller will monitor engine idle time.
In a configuration disclosed here as "excessive idle control," the
generator controller may be configured with a pre-set maximum
allowed idle time. If the maximum idle time is reached--a condition
referred to here as an "excessive idle scenario" or an "excessive
idle case"--the generator controller will signal the load bank
controller to initiate the load bank. The system will then be
required to complete a load cycle, as described above, before
resuming idle speeds. If a user attempts to disrupt the load cycle,
the generator controller will initiate a warning to the user. If a
user nonetheless disrupts the load cycle, the generator controller
will disable the system and will not allow operation until a load
cycle has been completed at full engine speed. The load under which
the generator operates during the load cycle could include any
combination of real load and dummy load levels, as long as P.sub.G
is maintained. In accordance with some embodiments, for every three
(3) hour period of engine idle time, the engine must complete a
load cycle of one (1) hour.
[0015] In accordance with some embodiments of the disclosed
technology, the generator controller may be configured with what is
disclosed here as a "load dump" feature. In such a configuration,
the generator controller signals the load bank controller to
disconnect, or dump, the load bank if the generator controller
and/or load bank recognizes a "load spike" of monitored load. Load
spike, as used here, is a scenario in which the load connected to
the engine-generator exceeds some pre-set value.
[0016] In accordance with some embodiments of the disclosed
technology, the generator controller controls the load bank
directly, thus obviating the need for a separate load bank
controller.
[0017] In accordance with some embodiments of the disclosed
technology, the system may be equipped with remote monitoring.
[0018] In accordance with some embodiments of the disclosed
technology, the generator controller is configured with a manual
setting. In the manual setting, the load bank may be engaged or
disengaged by manual operation. In the manual setting, an operator
may manually direct the controller to increase or decrease total
resistance of the load bank.
[0019] In accordance with some embodiments of the disclosed
technology, the load bank may be completely disabled and locked out
of operation. In such a state, the total load of the generator is
equal to the real load.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1A is a single-line diagram of an embodiment of the
disclosed system.
[0021] FIG. 1B is a single-line diagram of an embodiment of the
disclosed system.
[0022] FIG. 2 is a flow chart depicting an operating configuration
of an embodiment of the disclosed system.
[0023] FIG. 3 is a block diagram depicting a method of operating
embodiments of the disclosed system.
DETAILED DESCRIPTION
[0024] Reference will now be made in detail to embodiments,
examples of which are illustrated in the accompanying drawings. In
the following detailed description, numerous specific details are
set forth in order to provide a thorough understanding of the
disclosed concepts. It will, however, be apparent to one of
ordinary skill in the art that the disclosed concepts may be
practiced without these specific details. Well-known methods,
procedures, components, circuits, and networks have not been
described in detail so as not to unnecessarily obscure aspects of
the embodiments.
[0025] FIG. 1A depicts an engine-generator and load bank system 10
comprising an engine 12 mechanically connected and configured to
drive an alternator 14. This combination is referred to as an
engine-generator. The generator portion of the engine-generator, or
alternator 14, is connected to an output bus 16, which is connected
to a real load 17, and a load bank bus 18, which is connected to a
load bank 19. The output bus 16 and load bank bus 18 are connected
to the alternator 14 by way of disconnects 21. The disconnects 21
could comprise circuit breakers or fused switches.
[0026] The alternator 14 may be sized and configured for a variety
of rated output. In some embodiments, the alternator 14 is
adjustable to provide a variety of voltage outputs as selected by a
user. The alternator 14 may be single-phase or poly-phase; and it
may be rated for a variety of operating frequencies. In one
embodiment, the alternator 14 is rated 240Y/139 V, three-phase,
four-wire, 60 Hz, and is adjustable for operation at 208Y/120 V. In
one embodiment, the alternator 14 is rated 480Y/277 V, three-phase,
four-wire, 60 Hz.
[0027] The engine 12 is equipped with an engine control module 20
and a diesel particulate filter (DPF) 22. The system 10 also has at
least one load monitoring device 24 that is in electrical
communication with the output bus 16 and the load bank bus 18. The
load monitoring device 24 could be any piece or combination of
electrical metering equipment suitable for gathering and
communicating data about system voltage, current, and/or power. In
a preferred embodiment, the load monitoring device 24 comprises
current transformers.
[0028] The system 10 comprises a generator controller 26 which is
connected to the engine control module 20 via a communication means
27. The communication means 27 could be any communication bus
suitable for communication between, and for diagnostics of engine
components. In a preferred embodiment, the communication means 27
comprises SAE J1939-based protocol.
[0029] The generator controller 26 has a load dump output 28 and a
load enable output 30. The system 10 also includes a load bank
controller 32 which has a load enable input 34, a load dump input
36, and a load sensor 38. The load sensor 38 is connected to and
accepts an input from the load monitoring device 24 for monitoring
the combined load of the real load 17 and the load bank 19.
[0030] The load bank controller 32 is also equipped with at least
one load step output 40. The load bank controller 32 could have one
or a plurality of load step outputs 40. The at least one load step
output 40 is connected to at least one load step contactor 42,
which control(s) the electrical connection of at least one load
step resistor 44 to the load bank bus 18. The output bus 16, load
bank bus 18, and load step resistor(s) 44 may be single- or
poly-phase, as required for operation with the configuration of the
alternator 14. In a preferred embodiment, the load bank controller
32 is equipped with four load step outputs 40. In a preferred
embodiment, there are four (4) load step resistors 44, each rated
25 kW at 480 V, such that the total rated resistance of the load
bank 19 is 100 kW at 480 V, with a power factor of 1.0.
[0031] In one embodiment, the engine 12, which is equipped with a
radiator, and alternator 14 are mounted within one enclosure, and
the load bank 19 is mounted within a separate enclosure that is
physically connected to the engine-generator enclosure adjacent to
the radiator of the engine 12. In such an embodiment, the radiator
of the engine 12 forces air over the load step resistor(s) 44. In
another embodiment, the load bank 19 is remotely located, and it is
physically connected to the engine 12 and alternator 14 only to the
extent necessary to facilitate electrical communication and
control. In another embodiment, the load bank 19, the engine 12,
and the alternator 14 are configured on a common base, which could
include a common trailer or skid, within a single enclosure.
[0032] The system 10 may also be equipped with a remote
communications module 46 and an antenna 48. The remote
communications module 46 could comprise terrestrial wireless or
satellite communications technology, or a combination of both, in
tandem or redundantly. The remote communications module 46 allows
the system 10 to periodically, or on demand, transmit data that may
be monitored. Such data may include the status of the engine 12,
the DPF 22, and the load bank 19. The remote communications module
46 could also be equipped with means for transmitting a location
via a global positioning system (GPS), or the like. The remote
communications module 46 may also be equipped to receive data and
relay it to the generator controller 26 for remote control of the
system 10. In one embodiment of the system 10 equipped with a
remote communications module 46, a fault condition in any portion
of the system 10 will cause an alert to be sent to an operator via
phone text message (SMS) or via electronic mail.
[0033] Specific data transmitted by the remote communications
module 46 may include: the fuel level of the engine 12 in a range
from 0 to 100%; the fuel consumption rate of the engine 12 in
gallons per hour; oil pressure of the engine 12 in pounds per
square inch; temperature of the coolant in the engine 12 in degrees
Fahrenheit or degrees Celsius; the on/off status of the DPF 22; the
soot level of the DPF 22; whether the DPF 22 regeneration function
has been inhibited or disabled; the temperature of the exhaust of
the engine 12 at various points within engine 12; the operating
status of the load bank 19, and whether the load bank 19 has
correctly responded to a demand request from the generator
controller 26.
[0034] FIG. 1B depicts an embodiment of an engine-generator and
load bank system 10 comprising an engine 12 mechanically connected
and configured to drive an alternator 14. The alternator 14 is
connected to an output bus 16, which is connected to a real load
17, and a load bank bus 18, which is connected to a load bank 19.
The outputs bus 16 and load bank bus 18 are connected to the
alternator by way of disconnects 21, which could comprise circuit
breakers or fused switches. In such an embodiment, the alternator
14 may be sized and configured as described above.
[0035] In the embodiment of FIG. 1B, the engine 12 is equipped with
an engine control module 20 and a DPF 22. The system 10 comprises a
generator controller 26 that is connected to the engine 12 via a
communication means 27, which could be any suitable communication
bus as described above. The generator controller 26 is equipped
with at least one load step output 40; it could have one or a
plurality of load step outputs 40. The load step output(s) 40
is/are connected to one or more load step contactor(s) 42, which
control the electrical connection of at least one load step
resistor 44 to the load bank bus 18. The electrical system of such
an embodiment may be single- or poly-phase, as described above.
[0036] In the embodiment of FIG. 1B, the generator controller 26
monitors the loading of the alternator 14 by extrapolation. The
generator controller 26 receives engine operation information from
the engine control module 20 via the communication means 27, which
information the generator controller 26 uses to determine loading
conditions of alternator 14. The generator controller 26 then
directly controls the load bank 19 by way of the load step
output(s) 40 and load step contactor(s) 42 as necessary in cases of
neglect, regeneration, and excessive idle.
[0037] FIG. 2 depicts a control system that the generator
controller 26 may employ to control the system 10. The generator
controller 26 first evaluates generator operating status 50 to
determine if the engine 12 is in an acceptable operating condition
52. Whether the engine 12 is in an acceptable operating condition
is a function of whether a neglect scenario or excessive idle
scenario is present. Cases of neglect and excessive idle correspond
to an engine 12 being in an unacceptable operating condition.
Further, whether the engine 12 is in an acceptable operating
condition depends on whether the exhaust temperature is sufficient
to provide for effective regeneration. If the exhaust temperature
is too low for effective regeneration, and if the engine 12 is in a
regeneration scenario, the engine is not in an acceptable operating
condition.
[0038] If the engine 12 is in an acceptable operating condition,
the load bank 19 is or remains disconnected 54. If the engine 12 is
not in an acceptable operating condition, the generator controller
26 determines whether the engine 12 has operated in an unacceptable
state for a pre-set time 56. If the engine 12 has operated in an
unacceptable condition for a pre-set time, the load bank 19 is
connected 58. That is, the generator controller 26 signals the load
bank controller 32 via the load enable output 30 and load enable
input 34 to initiate the load bank 19 by way of the load step
output 40 and the load step contactor(s) 42. Or, in an embodiment
without a load bank controller 32, the generator controller 26
controls the load bank 19 directly. The load bank 19 is then
operated as described supra. If the engine 12 has not operated in
an unacceptable condition for a pre-set time, the load bank 19 is
or remains disconnected 54.
[0039] Once the load bank 19 is connected, it remains connected for
a pre-set time, as required for a load cycle. While the load bank
19 is connected, the generator controller 26 and/or the load bank
controller 32 determine whether a load spike is present 60. If a
load spike is present, the generator controller 26 effects a load
dump by signaling the load bank controller 32, either directly or
via load dump output 28 and load dump input 36, so that the load
bank 19 is disconnected 54. If a load spike is not present, the
generator controller 26 determines whether the load cycle is
complete 64. If the load cycle is complete, the evaluation begins
anew 50. If the load cycle is not complete, the load cycle will
resume upon restarting 62 the system 10.
[0040] FIG. 3 depicts a method of operating the system 10 by
configuring the generator controller 26. The method involves first
setting a rated operating load 68. Then, it requires setting: a
load window 70, a duration 72, a max idle time 74, and a minimum
acceptable load 76 for DPF regeneration. Next, it involves
monitoring: the load 78, idle time 80, and regeneration status 82.
Then, it involves initiating a load cycle 84 when monitored
conditions reach set points that correspond to cases of neglect,
regeneration, or excessive idle. Finally, it involves dumping the
load bank 86 in the presence of a load spike.
[0041] The foregoing description, for purpose of explanation, has
been described with reference to specific embodiments. The
illustrative discussion above, however, is not intended to be
exhaustive or to limit the disclosed concepts to any particular
form. The embodiments were chosen and described in order to best
explain the principles of the disclosed concepts in order to enable
others skilled in the art.
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