U.S. patent number RE40,286 [Application Number 11/116,459] was granted by the patent office on 2008-05-06 for system and method for supplying auxiliary power to a large diesel engine.
This patent grant is currently assigned to CSX Transportation, Inc.. Invention is credited to Lawrence J. Biess, Christer T. Gotmalm.
United States Patent |
RE40,286 |
Biess , et al. |
May 6, 2008 |
System and method for supplying auxiliary power to a large diesel
engine
Abstract
A system and method for providing auxiliary power to a large
diesel engine allowing shutdown of such large engine in all weather
conditions. An auxiliary power unit made up of a secondary engine
coupled to an electrical generator is provided. An automatic
control system shuts down the primary engine after a period of
idling and the auxiliary power unit provides electrical power for
heating and air conditioning. In cold weather, the auxiliary power
unit maintains the primary engine coolant and lube-oil warm to
facilitate engine restart. The coolant system is kept warm using a
heat exchanger and electrical heaters. The lube-oil system is kept
warm using a recirculating pump and electrical heaters. In warm
weather, the auxiliary power unit provides electrical power for air
conditioning and other hotel loads. The auxiliary power unit
isolates the primary engine batteries during operation and provides
electrical power for hotel and non-vital loads.
Inventors: |
Biess; Lawrence J.
(Jacksonville, FL), Gotmalm; Christer T. (Sault Ste Marie,
CA) |
Assignee: |
CSX Transportation, Inc.
(Jacksonville, FL)
|
Family
ID: |
25097130 |
Appl.
No.: |
11/116,459 |
Filed: |
April 28, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
09773072 |
Jan 31, 2001 |
06470844 |
Oct 29, 2002 |
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Current U.S.
Class: |
123/142.5R |
Current CPC
Class: |
F01M
5/021 (20130101); F02D 25/04 (20130101); F02B
3/06 (20130101); F02F 2007/0097 (20130101) |
Current International
Class: |
F02N
17/02 (20060101) |
Field of
Search: |
;123/142.5R,DIG.8,179.19,142.5E,196AB,198D |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Cronin; Stephen K.
Assistant Examiner: Ali; Hyder
Attorney, Agent or Firm: McGuireWoods LLP
Claims
What is claimed is:
1. An auxiliary power system for operation in cooperation with a
primary engine having a battery, comprising (A) a secondary engine,
and (B) control means having a timer, wherein: (i) such control
means shuts down such primary engine following a predetermined time
period of idling of such primary engine; and (ii) such control
means enables automatic operation of such secondary engine.
2. The auxiliary power system of claim 1, in which such control
means starts such secondary engine in response to a predetermined
ambient temperature if such primary engine is not operating.
3. The auxiliary power system of claim 1, further comprising an
electrical power producing means driven by such secondary
engine.
4. The auxiliary power system of claim 3, in which such electrical
power producing means comprises a 240 vac, 60 Hz, single-phase
electrical generator.
5. The auxiliary power system of claim 4, in which such electrical
generator produces at least 17 kva of power.
6. The auxiliary power system of claim 4, further comprising
battery charging means.
7. The auxiliary power system of claim 6, in which such control
means (i) isolates the battery of the primary engine from all dc
loads upon operation of such secondary engine, and (ii)
continuously charges the battery during operation of such secondary
engine.
8. The auxiliary power system of claim 1, further comprising (A)
primary engine coolant pumping means, and (B) heat exchanging
means.
9. The auxiliary power system of claim 8, further comprising engine
coolant heating means.
10. The auxiliary power system of claim 9 further including,
coolant temperature sensing means, and in which such control means
maintains primary engine coolant temperature within a predetermined
temperature range.
11. The auxiliary power system of claim 9, in which such engine
coolant heating means comprises electric heaters.
12. The auxiliary power system of claim 1, further comprising
primary engine lube-oil pumping means.
13. The auxiliary power system of claim 12, further comprising,
lube-oil heating means.
14. The auxiliary power system of claim 13, further including,
primary lube-oil temperature sensing means, and in which such
control means maintains primary engine lube-oil temperature within
a predetermined temperature range.
15. The auxiliary power system of claim 13, in which such lube-oil
heating means comprises electric heaters.
16. The auxiliary power system of claim 1, further comprising a
remotely operable primary engine coolant drain valve.
17. The auxiliary power system of claim 16, in which such control
means causes such remotely operable drain valve to open and drain
the primary engine coolant after a predetermined period of time in
response to a predetermined ambient temperature if such primary
engine is not operating and such secondary engine fails to
start.
18. A method of supplying auxiliary power to a primary engine,
comprising the steps of: (A) providing a secondary engine coupled
to an electrical generator; (B) providing a controller having (i) a
primary engine idle timer; and (ii) a plurality of selectable
control modes; (C) monitoring the operating condition of such
primary engine; (D) automatically shutting down such primary engine
following idling of such primary engine for a predetermined period
of time; and (E) operating such secondary engine in response to a
predetermined condition of such primary engine.
19. Method of supplying auxiliary power to a primary engine of
claim 18, wherein such predetermined condition of such primary
engine is selected from the group consisting of: (i) if such
controller is selected to a first mode, (a) starting such secondary
engine is response to a first selected coolant temperature or
lube-oil temperature; and (b) shutting down such secondary engine
is response to a second selected coolant temperature or lube-oil
temperature; (ii) if such controller is selected to a second mode,
(a) enabling manual control of such secondary engine; (b) starting
such secondary engine is response to a first selected coolant
temperature or lube-oil temperature; and (c) shutting down such
secondary engine is response to a second selected coolant
temperature or lube-oil temperature; and (iii) if such controller
is selected to a third mode, (a) enabling manual control of such
secondary engine.
20. Method of claim 18, further comprising providing heating means
for such primary engine coolant, and providing heating means for
such primary engine lube-oil.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to large engine systems, but more
specifically to a system and method for supplying auxiliary power
to a locomotive engine to permit automatic shutdown of such
locomotive engine in all weather conditions.
2. Background of the Invention
Generally, large diesel engines, such as locomotive engines are not
shut down during cold weather conditions due to the difficulty in
restarting. Diesel engines do not have the benefit of an electric
spark to generate combustion and must rely on heat generated by
compressing air to ignite fuel in the engine cylinders. In low
temperature conditions (ambient temperatures below about 40.degree.
F.), two major factors contribute to the difficulty in starting a
diesel engine. First, cold ambient air drawn into the engine must
be increased in temperature sufficiently to cause combustion.
Second, diesel fuel tends to exhibit poor viscous qualities at low
temperatures, making engine starting difficult. Furthermore, engine
oil that provides lubrication for the engine is most effective
within specific temperature limits, generally corresponding to
normal operating temperature of the engine. When cold, the engine
lube-oil tends to impede engine starting. Moreover, most engines
require a large electrical supply, typically provided by a battery,
in order to turn over and start the engine. Unfortunately,
batteries are also adversely affected by severe cold weather.
In cold weather, large engines are typically idled overnight to
avoid the necessity to restart in the morning and to provide heat
to the crew space. Locomotives that must operate in extremely cold
environmental conditions must be run continuously, at high fuel
cost, or, when shutdown, must be drained of engine coolant and
provided supplemental electrical service and heaters, also at high
cost.
In warm weather, locomotive engines typically idle to provide air
conditioning and other services, including lighting, air pressure
and electrical appliances. If the locomotive is shut down,
solid-state static inverters that transform dc power from the
locomotive batteries to useful ac power can provide electrical
power for air conditioning and other services. Devices such as
inverters are parasitic loads that tend to drain the batteries,
which will adversely affect engine reliability. Alternatively,
wayside electrical power can be supplied, but it generally does not
maintain air conditioning.
Several systems have been designed to maintain warmth in a large
diesel engine under low temperature ambient conditions. For
example, U.S. Pat. No. 4,424,775 shows an auxiliary engine for
maintaining the coolant, lube-oil, and batteries of a primary
diesel engine in restarting condition by using the heat of the
auxiliary engine exhaust, to keep coolant, lube-oil, and batteries
sufficiently warm. U.S. Pat. No. 4,762,170 shows a system for
facilitating the restarting of a truck diesel engine in cold
weather by maintaining the fuel, coolant, and lube-oil warm through
interconnected fluid systems. U.S. Pat. No. 4,711,204 discloses a
small diesel engine for providing heat to the coolant of a primary
diesel engine in cold weather. The small engine drives a
centrifugal pump with restricted flow such that the coolant is
heated, and then pumped through the primary cooling lines in
reverse flow. In many of such systems, an electrical generator or
inverter may be included to maintain a charge for the
batteries.
None of them, however, specifically address other problems
associated with the idling of a large diesel engine, such as,
primary engine wear, wet stacking due to piston ring leakage as a
result of idling for long periods of time in cold weather, high
fuel and lube-oil consumption, and so forth. No effective
alternative to warm weather idling is known to exist.
SUMMARY OF THE INVENTION
An objective of the present invention is to provide a reliable
auxiliary power supply system to allow for shutting down a primary
diesel engine in all weather conditions.
Another object is to provide a system that will start an auxiliary
power unit to maintain a primary engine warm in response to a
predetermined ambient temperature.
Another object is to provide a system that will shut down a primary
engine after a certain predetermined period of time, regardless of
ambient temperature, and start an auxiliary power unit.
Another object is to provide a system that will maintain fuel,
coolant, and lube-oil of a primary engine at a sufficiently warm
temperature to facilitate restarting such primary engine in cold
weather. A more specific objective of the present invention is to
keep a primary engine coolant warm by using electrical heaters and
a heat exchanger. A related object is to keep a primary engine
lube-oil warm by using a recirculating pump and electrical
heaters.
A further objective of the present invention is to provide heating
and air conditioning to the cab compartment for crew comfort.
Another object of the present invention is to provide an electrical
generator for charging the primary engine's batteries, as well as
for generating standard 240 vac and 120 vac to permit the use of
non-vital and hotel loads.
A more specific object of the invention is to isolate a primary
engine's batteries when such primary engine is shut down to prevent
discharge of the batteries.
The present invention provides such a system and method that
furnishes cold weather layover protection automatically in a mobile
package that will protect primary engine systems and cab components
against freezing. Prior art solutions require the primary engine to
remain operating or require use of wayside stations. The present
invention allows for automatic shutdown of a primary engine instead
of extended idling operation while maintaining a charge on the
primary engine's battery. Prior art solutions that allow automatic
primary engine shutdown require the primary engine to be
automatically started and idled in order to protect the primary
engine from freezing, or that the primary engine start in response
to a low primary engine battery charge. The present invention
allows for the operation of cab air conditioning while the primary
engine is shut down. Prior art solutions require the primary engine
to operate in order to provide air conditioning. The present
invention provides electrical power in standard household voltages
for hotel and non-vital loads allowing for the installation and use
of commonly available electrical devices without the need to
maintain the primary engine operating. Prior art solutions rely
upon the use of 74 vdc locomotive power with specially designed
components. Such components are expensive and in limited supply
since they must be designed to operate on an unconventional voltage
not widely used outside the railroad industry, or they require the
use of solid-state inverters. In either case, the primary engine
must remain operating to provide electrical power or the batteries
will discharge.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features, aspects, and advantages of the
present invention are considered in more detail, in relation to the
following description of embodiments thereof shown in the
accompanying drawings, in which:
FIG. 1 is a schematic overview of components of an embodiment of
the present invention;
FIG. 2 is a block diagram illustration of mechanical components of
an embodiment of the invention;
FIG. 3 is a block diagram illustration of mechanical components of
the invention for describing features of an auxiliary engine
coolant system;
FIG. 4 is a block diagram illustration of mechanical components of
the invention for describing features of an auxiliary engine
lube-oil system;
FIG. 5 is a block diagram illustration of electrical components of
the invention for describing operational features of an embodiment
of the present invention;
FIG. 6 is a block diagram illustration of electrical components of
the invention for describing electrical control features of an
embodiment of the present invention;
FIG. 7 is an electrical schematic diagram of a portion of FIG.
5;
FIG. 8 is an wiring diagram of electrical control circuits for
describing operational features of an embodiment of the invention;
and
FIG. 9 is a flowchart illustrating logical steps carried out by one
embodiment of the present invention for operation of the system
disclosed herein.
DETAILED DESCRIPTION OF THE INVENTION
The invention summarized above and defined by the enumerated claims
may be better understood by referring to the following detailed
description, which should be read in conjunction with the
accompanying drawings in which like reference numbers are used for
like parts. This detailed description of an embodiment, set out
below to enable one to build and use an implementation of the
invention, is not intended to limit the enumerated claims, but to
serve as a particular example thereof. Those skilled in the art
should appreciate that they may readily use the conception and
specific embodiment disclosed as a basis for modifying or designing
other methods and systems for carrying out the same purposes of the
present invention. Those skilled in the art should also realize
that such equivalent assemblies do not depart from the spirit and
scope of the invention in its broadest form.
The present invention enables an improved system for providing
heating or cooling and electricity to a railroad locomotive in all
operating environments, and saves locomotive fuel and lubricating
oil. An auxiliary power unit comprising a diesel engine coupled to
an electrical generator is installed in a locomotive cab. In a
preferred embodiment, the engine may be a turbo charged,
four-cylinder diesel engine, such as one manufactured by Kubota,
and rated at about 32 brake horsepower, at 1800 RPM. The auxiliary
unit engine can draw fuel directly from the main locomotive fuel
tank. Equipping the auxiliary unit with a 20-gallon lube-oil sump
and recirculating pump to permit extended oil change intervals can
minimize maintenance of such auxiliary unit engine. For protection
of the auxiliary unit engine, it should also be equipped with
over-temperature and low lube-oil pressure-shutdowns-to-prevent
engine damage in the event that the engine overheats or runs low on
lube-oil.
In a preferred embodiment, the electrical generator may be a 17
kva, 240 vac/60 Hz single-phase generator, mechanically coupled to
such engine. A 240 vac/74 vdc battery charger, such as a Lamarche
A-40 locomotive battery charger for the locomotive batteries is
provided to maintain the locomotive battery charged whenever the
auxiliary unit is operating.
Referring now to the drawings, there is presented a system overview
of an exemplary embodiment of the present invention. In a specific
embodiment, illustrated in FIG. 1, a primary engine 10 has an
integral cooling system including radiator 13 for dissipating heat
absorbed from primary engine 10 and support components such as
lube-oil cooler 15. The flow path of coolant for the primary engine
10 forms a closed loop. Coolant exits primary engine 10 at junction
17 through exit conduit 19 and flows to radiator 13 wherein heat is
transferred from such coolant to the atmosphere. Such coolant flows
through transfer conduit 22 to oil cooler 15 wherein heat is
transferred from lubricating oil for primary engine 10 to such
coolant. Such coolant flows through return conduit 25 to reenter
primary engine 10 at strainer housing 27. Engine coolant drain line
28 is provided to enable removal of coolant during cold weather to
prevent freeze damage.
Primary engine lube-oil provides lubrication for primary engine 10
and helps remove heat of combustion from primary engine 10. Such
lube-oil exits primary engine 10 at junction 30 through exit pipe
31 to oil cooler 15 where it transfers heat to the primary coolant.
Lube-oil exits oil cooler 15, travels to oil filter 33 through
connector pipe 35 and returns to primary engine 10 through return
pipe 37. Filter drain line 40 connects to strainer housing 27 and
is provided to enable draining of oil from the system during
periodic maintenance. During periodic oil changes, lube-oil is
drained from the entire system through lube-oil drain 42.
In accordance with the present invention there is provided a
secondary engine 45 having an electrical generator 48 mechanically
coupled to such secondary engine 45. Secondary engine 45 may be a
turbo charged, four-cylinder diesel engine, such as one
manufactured by Kubota, and rated at 32 bhp at 1800 RPM. Such
engine can draw fuel directly from the primary engine fuel tank.
Secondary engine 45 draws fuel for operation from a common fuel
supply for the primary engine 10 through fuel connections 51, 52.
Secondary engine 45 presents a separate closed loop auxiliary
coolant system 55 including heat exchanger 57, which is designed to
transfer heat generated by operation of secondary engine 45 to a
system designed to maintain primary engine 10 warm. Auxiliary
coolant in such separate closed loop system 55 flows through
secondary engine 45 and absorbs waste heat generated by internal
combustion within secondary engine 45. Such auxiliary coolant flows
to heat exchanger 57 where it transfers such absorbed heat to
primary engine coolant in a separate loop.
Referring to FIG. 2, two auxiliary loops are provided to maintain
primary engine 10 warm in cold environmental conditions. The
present apparatus utilizes two pumps shown at 62 and 77. Pump 62 is
used for conditioning of coolant. Pump 77 is used for conditioning
of lube-oil. Coolant loop 60 includes coolant pump 62 which can be
electrically driven, or, in an alternate embodiment, can be driven
directly by secondary engine 45. The inlet of pump 62 is
operatively connected by a conduit to a suitable location in the
coolant system of primary engine 10.
Pump 62 is powered by an electric motor 63. Its outlet at 64 is
connected to a conduit leading to the inlet of heat exchanger 57.
Coolant is discharged from pump 62 to heat exchanger 57. (For
clarity, the connections on heat exchanger 57 have been numbered in
FIGS. 2 and 3.) Coolants enters heat exchanger 57 at 2 and exits at
1, to coolant heater 65. A conduit connects the outlet of heat
exchanger 57 to coolant heater 65.
Coolant heater 65, in coolant loop 60, augments heat exchanger 57
to add heat to primary engine coolant. In a preferred embodiment,
coolant heater 65 includes three electrical water heater elements
66, 67, 68 of about 3 kw each. Alternate embodiments can include
more or less heater elements and heater elements of different
sizes. Coolant heater 65 includes coolant thermostat 70 for
determining coolant temperature and thermometer 73 for displaying
primary engine temperature. Coolant thermostat 70 is employed in a
coolant temperature control circuit as described later herein. In a
preferred embodiment, coolant from primary engine 10 is drawn from
a connection in engine coolant drain line 28 (FIG. 1) by the
suction of pump 62. Other coolant suction locations can be selected
as desired. Coolant then travels to heat exchanger 57 and coolant
heater 65 and returns to primary engine 10 via a return conduit.
Such conduit may include a suitable check valve and isolation valve
(not shown). Such a check valve may permit passage of coolant to
pump 62, but does not permit entry of liquid into coolant loop 60
upstream of coolant heater 65 when primary engine 10 is operating.
A primary engine water drain valve 74 (FIG. 1) opens and drains
primary engine 10 of coolant in order to protect primary engine 10
from freeze damage in the event that secondary engine 45 fails to
start and no operator action is taken. Control of primary engine
coolant temperature by components of coolant loop 60 is described
in more detail later herein with reference to FIGS. 7 and 8.
Lube-oil loop 75 includes oil pump 77 which can be electrically
driven, or, in an alternate embodiment, can be driven directly by
secondary engine 45. In a preferred embodiment, oil pump 77 may be
a positive displacement pump and a motor 78 powers the oil pump 77.
Oil heater 79 in lube-oil loop 75 adds heat to primary engine
lube-oil. In a preferred embodiment, oil heater 79 includes two
electrical oil heater elements 80, 81 of about 3kw each. Alternate
embodiments can include more or less heater elements and heater
elements of different sizes. Oil heater 79 includes oil thermostat
83 for determining lube-oil temperature and thermometer 85 for
displaying primary engine lube-oil temperature. Oil thermostat 83
is employed in an oil temperature control circuit as described
later herein. In a preferred embodiment, oil from primary engine 10
is drawn from a connection in lube-oil drain line 42 (FIG. 1) by
the suction of oil pump 77 in the direction of arrow 88 (FIG. 1).
Other oil suction locations can be selected as desired. Lube-oil is
discharged from pump 77 to oil heater 79 and returns to primary
engine 10 via a connection in filter drain line 40 (FIG. 1). Other
oil return locations can be selected as desired. Control of primary
engine lube-oil temperature by components of lube-oil loop 75 is
described in more detail later herein with reference to FIGS. 7 and
8.
FIG. 3 illustrates an auxiliary coolant system for secondary engine
45. Coolant in such system absorbs waste heat of combustion from
secondary engine 45 and transfers such heat in heat exchanger 57 to
coolant loop 60 (FIG. 2). (For clarity, the connections on heat
exchanger 57 have been numbered in FIGS. 2 and 3.) Auxiliary
coolant enters heat exchanger 57 at 4 and exits at 3, and then
travels to make up water tank 90 and returns to secondary engine
45. Make up water tank 90 is disposed in such auxiliary coolant
system to ensure sufficient coolant is available to safely operate
secondary engine 45. An engine temperature-sensing device 92 is
included to display operating temperature of secondary engine
45.
FIG. 4 illustrates a lube-oil system for secondary engine 45. A
large oil sump 95 or reservoir is provided to enable extended
operation between oil changes in conjunction with periodic
maintenance of primary engine 10. Oil is drawn from sump 95 through
filter 97 to oil change block 100, which contains a metering nozzle
101 to control the amount of oil flow to secondary engine 45. Also
contained in oil change block 100 is an integral relief valve 103
to protect secondary engine components from an overpressure
condition. If relief valve 103 lifts, oil is directed back to sump
95. Such secondary engine lube-oil system is also provided with a
crankcase overflow 105 to prevent damage to secondary engine
components from excess oil in the engine crankcase. Engine oil
pressure and oil temperature sensing devices 106 are included to
display operating oil temperature and pressure of secondary engine
45. For protection of the secondary engine 45, it is also equipped
with over temperature and low lube-oil pressure shutdowns to
prevent engine damage in the event that the engine overheats or
runs low on lube-oil.
In an alternate embodiment, the lube-oil system of secondary engine
45 can be cross-connected with lube-oil loop 75 of primary engine
10. Referring to FIG. 1, oil can be drawn from secondary engine 45
at junction 110 through pipe 111 in the direction identified by
arrow 113, and then into oil pump 77. At least a portion of the
discharge of oil pump 77 is directed back to secondary-engine 45
through connecting pipe 115 as indicated by arrow 119. Equipping
the secondary engine 45 with a large lube-oil sump, such as
20-gallon capacity and pump 77 can permit extended oil change
intervals and minimize maintenance of secondary engine 45.
FIG. 5 is a block diagram overview of an electrical distribution
system according to an embodiment of the present invention.
Electrical power to start secondary engine 45 is provided by a
separate battery 120 dedicated to such purpose, which may be a
standard 12 vdc battery. Starter 122 turns over secondary engine 45
upon a start signal as described later herein in relation to FIG.
9. Alternator 125 maintains battery 120 in a ready condition during
operation of secondary engine 45. Electrical generator 48 may be a
17 kva, 240 vac/60 Hz single-phase generator, mechanically coupled
to secondary engine 45. Other size and capacity generators may be
used. The output of generator 48 is routed to output junction box
130 where electrical power is distributed to selected electrical
loads such as, 240 vac/74 vdc battery charger 132, such as a
Lamarche A-40 locomotive battery charger for the locomotive
batteries to maintain the primary engine battery charged whenever
the secondary engine is operating. Other electrical loads may
include auxiliary air compressor 133, air conditioner unit 134, and
cab heater 135. In a preferred embodiment, cab comfort may be
maintained during cold weather periods by supplemental cab heaters
135 that respond to a wall-mounted thermostat. There may also be
provided a 240 vac cab air conditioner 134 to maintain cab comfort
during warm weather periods. There can also be provided an
electrical or mechanically driven air compressor 133 to maintain
train line air pressure and volume.
Other 240 vac electrical loads include electrical water heater
elements 66, 67, 68, and electrical oil heater elements 80, 81. The
electric water heater elements and the electric oil heater elements
serve two purposes. One purpose is to provide immersion heat for
the coolant loop 60 and lube-oil loop 75. The second purpose is to
load the secondary engine 45 through generator 48 and transfer the
heat generated by this load through heat exchanger 57 into primary
engine coolant in loop 60.
Referring to FIG. 6, 240 vac output from generator 48 can also be
reduced to standard household 120 vac for lighting 136 and
receptacles 137, through circuit breakers 138 and 139 respectively.
240 vac and 120 vac outlets provide for non-vital electrical and
hotel loads. For operational purposes, some 240 vac breakers may be
interlocked as illustrated in FIG. 6. For example, to prevent
overload of generator 48 during warm weather operation, air
conditioner circuit breaker 140 is interlocked with electric heater
circuit breaker 142 such that both circuit breakers cannot be
closed at the same time. In addition, there is no need to operate
air conditioner 134 simultaneously with cab heaters 135,
accordingly air conditioner circuit breaker 140 is interlocked with
cab heater circuit breaker 145 such that both circuit breakers
cannot be closed at the same time. Electric power for a 240 vac/74
vdc battery charger 132 is provided through circuit breaker 149 to
maintain the primary engine battery 150 charged whenever the
secondary engine 45 is operating.
FIG. 7 is an electrical schematic diagram of electrical control
panel 150 included in a preferred embodiment for describing control
features of the present invention. Control panel 150 contains
circuit breakers and indicators for the electrical circuits. Main
circuit breaker 151 is provided in panel 150 to break main power
from generator 48. Circuit breakers are also provided for systems
as described in relation to FIGS. 5 and 6, such as air conditioning
134, cab heater 135 and battery charger 132. Panel 150 also
contains breakers for coolant water pump 80 and oil pump 77.
Switches for oil heaters 80, 81 and for water heaters 66, 67, 68
are also provided in panel 150. Voltmeter 153, located in panel 150
is provided to monitor the output of generator 48. A 24 vac
secondary voltage circuit 155 is supplied to operate contactors and
indicating lighting, such as power "on" indicator light 157, water
heater "on" indicator light 158, and oil heater "on" indicator
light 159. 240 vac to 24 vac step down transformer 161 is located
in panel 150. 240 vac to 120 vac step down transformer 163 is also
located in panel 150.
To maintain the primary engine 10 warm in low ambient temperature
conditions, a control system, such as illustrated in FIG. 8 is
provided. Locomotive coolant pump 62, heat exchanger 57, and
coolant heater 65, including immersion heaters 66, 67, 68 maintain
the primary engine cooling temperature above a preselected
temperature, such as 75.degree. F. A positive displacement lube-oil
recirculating pump 77 and oil heater 79, including immersion
heaters 80, 81 maintain locomotive lube-oil temperature above a
preselected temperature, such as 50.degree. F.
The various components of the apparatus can be electrically
controlled to provide automatic monitoring of its operation and
thermostatic control of the temperature of the liquids being
circulated through coolant loop 60 and lube-oil loop 75 to assure
proper operation of the conditioning apparatus to maintain engine
10 in readiness for use. An electric control unit, such as shown in
FIG. 8 is connected to the motors 63 and 78 for pumps 62, 77
respectively.
Coolant control circuit 170 controls operation of coolant pump 62
and coolant heater 65. The temperature of the coolant is monitored
by thermostatic element 70, and flow responsive switches 174 and
175 monitor the flow rate of coolant. Should flow be interrupted,
coolant control circuit 170 is capable of shutting down pump 62 to
assure against damage to the coolant or equipment. Thermostatic
element 70 further monitors the temperature of the coolant and
properly operates heating elements 66, 67, 68 through heater
element contact coil 178.
Under normal use, thermostatic element 70 is preset to a
temperature at which the coolant is desired while circulating
through engine 10, such as 75.degree. F. Until the circulating
coolant reaches this temperature, thermostatic element 70 will
continue operation of heating elements 66, 67, 68 to add heat to
coolant loop 60. The coolant is heated by direct contact along
heating elements 66, 67, 68. When the coolant reaches the desired
temperature, thermostatic element 70 will cause heating element
contactor coil 178 to open the circuit to heating elements 66, 67,
68 until the liquid temperature again falls below such
predetermined temperature level.
To insure against damage to the heating elements 66, 67, 68 due to
lack of liquid recirculation, the flow control switches 174, 175
monitor the passage of coolant through coolant heater 65. So long
as flow continues, switch 174 remains closed. It is opened by lack
of flow through coolant heater 65. This activation is used to
immediately open the circuit to the heating elements 66, 67, 68 to
prevent damage to them and to prevent damage to the coolant within
coolant heater 65. Coolant control circuit 170 also includes a time
delay coil 179 capable of monitoring activation of flow control
switch 175. If flow has ceased for a predetermined time, time delay
coil 179 will then shut down the entire apparatus and require
manual restarting of it. In this way, operation of the apparatus
can be automatically monitored while assuring that there will be no
damage to liquid being circulated, nor to the equipment or engine
10.
Lube-oil control circuit .[.170.]. .Iadd.180 .Iaddend.controls
operation of lube-oil pump 77 and lube-oil heater 79. The
temperature of the lube-oil is monitored by thermostatic element 83
and flow responsive switches 184 and 185 monitor the flow rate of
lube-oil. Should flow be interrupted, the lube-oil control circuit
180 is capable of shutting down pump 77 to assure against damage to
the oil or equipment. Thermostatic element 83 further monitors the
temperature of the lube-oil and properly operates heating elements
80, 81 through heater element contact coil 188. High limit
thermostat 183 operates as a safety switch to remove power from
heating elements 80, 81 in the event lube-oil temperature exceeds a
predetermined temperature.
Under normal use, thermostatic element 83 is preset to a
temperature at which the lube-oil is desired to maintain engine 10
warm, such as 50.degree. F. Until the circulating lube-oil reaches
this temperature, thermostatic element 83 continues operation of
heating elements 80, 81 to add heat to lube-oil loop 75. The
lube-oil is heated by direct contact along heating elements 80, 81.
When the lube-oil reaches the desired temperature, thermostatic
element 83 will cause heating element contactor coil 188 to open
the circuit to heating elements 80, 81 until the liquid temperature
again falls below such predetermined temperature level. If the
lube-oil reaches an unsafe temperature, high limit thermostat 183
will cause heating element contactor coil 188 to open the circuit
to heating elements 80, 81 until the liquid temperature again falls
below a predetermined temperature level.
To insure against damage to the heating elements 80,81 due to lack
of liquid recirculation, the flow control switches 184, 185 monitor
the passage of lube-oil through lube-oil heater 79. So long as flow
continues, switch 184 remains closed. It is opened by lack of flow
through lube-oil heater 79. This activation is used to immediately
open the circuit to the heating elements 80, 81 to prevent damage
to them and to prevent damage to the lube-oil within lube-oil
heater 79. Lube-oil control circuit 180 also includes a time delay
coil 189 capable of monitoring activation of flow control switch
185. If flow has ceased for a predetermined time, time delay coil
189 will then shut down the entire apparatus and require manual
restarting of it. In this way, operation of the apparatus can be
automatically monitored while assuring that there will be no damage
to liquid being circulated, nor to the equipment or engine 10.
The purpose of the apparatus is to provide circulation of coolant
and lubricant through the equipment or engine 10 while it is not
operation. Pumps 62 and 77 are preset to direct liquid to the loops
60, 75 respectively at pressures similar to the normal operating
pressures of the coolant and lubricant during use of the equipment
or engine. Thus, the coolant and lubricant, or other liquids used
in similar equipment, can be continuously circulated through the
non-operational equipment to effect heat transfer while the
equipment (or engine) is not in use. In the case of a lubricant,
surface lubricant is also effected, maintaining the movable
elements of the equipment in readiness for startup and subsequent
use. This prelubrication of the nonoperational equipment surfaces
minimizes the normal wear encountered between movable surfaces that
have remained stationary for substantial periods of time.
Control logic provides for a cooldown period for the automatic
heaters before automatic shutdown of secondary engine 45 to cool
and protect such energized electric heaters.
In accordance with the present invention, the system can be
operated in a variety of modes. FIG. 9 is a flowchart illustrating
logical steps carried out by one embodiment of the present
invention for operation of the system. In a preferred embodiment,
the secondary engine 45 can be selected for operation locally at an
engine control panel or remotely in the locomotive cab. Control
logic permits operation in any of the three modes "thermostat",
"cab", and "manual" described below.
During normal operation of primary engine 10, the secondary engine
45 is not in operation. An engine idle timer at block 200
determines if primary engine 10 has been idled for a predetermined
period of inactivity and idle operation, such as 30 minutes. After
such period of inactivity, the next logical step is to determine
the mode of operation of secondary engine 45.
If secondary engine 45 is selected to the "thermostat" mode,
indicated at block 205, automatic control features shut down
primary engine 10 as indicated at block 210. The "thermostat" mode
is a preferred mode of operation for maintaining primary engine 10
warm during cold weather ambient conditions. In "thermostat" mode,
the control system shuts down the primary engine 10 after a
predetermined period of inactivity and idle operation, such as 30
minutes. In response to a first predetermined environmental
condition 215, such as low locomotive coolant temperature or low
lube-oil temperature, the secondary engine 45 will start 220 in
order to warm primary engine systems as described later herein.
When a second predetermined environmental condition 225, such as
the selected temperature exceeds an established set point,
secondary engine 45 automatically shuts down 230. In a preferred
embodiment, such environmental condition may be engine coolant
temperature as measured by a primary engine block thermostat.
If secondary engine 45 is selected to the "cab" mode, indicated at
block 235, automatic control features shut down primary engine 10
as indicated at block 240. The "cab" mode is a preferred mode of
operation for warm weather operating to maximize fuel savings by
limiting idling operation of primary engine 10. In "cab" mode, the
control system automatically shuts down primary engine 10 after a
predetermined period of inactivity and idle operation, such as 30
minutes. An operator can start secondary engine 45 manually as
indicated at block 245. Secondary engine 45 remains operating upon
operator command. If an operator does not start secondary engine
45, it will start automatically in response to a first
predetermined environmental condition, such as low coolant
temperature or low lube-oil temperature, and shut down when the
selected temperature exceeds an established set point as described
for "thermostat" control above. In an alternate embodiment, an
override may be provided to permit extended idling operations at
the discretion of the operator.
The "manual" mode, indicated at block 250 allows secondary engine
45 to be started by means of manually priming secondary engine 45.
This provision allows for operation of secondary engine 45 in the
event that automatic start up features malfunction, or to prime
secondary engine 45, in the event it runs out of fuel.
In all modes of operation, secondary engine 45 charges the primary
batteries 150 and provides power to thermostatically controlled cab
heaters 140 and 120 vac lighting 136 and receptacles 137. In
operation, when primary engine 10 is shut down automatically a
blocking diode isolates the primary batteries 150 from 74 vdc loads
to prevent discharge of the locomotive battery 150 during the
shutdown period.
In an alternate embodiment, external audible and visual alarms can
sound and light if secondary engine 45 fails to start during a
thermostatically initiated start in cold weather.
In a still further embodiment, 120 vac internal and external
lighting can be controlled by means of photo sensors and motion
detectors for security of the locomotive.
While specific values, relationships, materials and steps have been
set forth for purposes of describing concepts of the invention, it
should be recognized that, in the light of the above teachings,
those skilled in the art can modify those specifics without
departing from basic concepts and operating principles of the
invention taught herein. Therefore, for purposes of determining the
scope of patent protection, reference shall be made to the appended
claims in combination with the above detailed description.
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