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EMP cooling systems solutions ppt 04 10 11
1. EMP PROPRIETARY INFORMATION
EMP Thermal System Capabilities
Thermal System Development and Example Proposal
Prepared By: Mark Bader
April 28, 2011
2. April 2011Page 2 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
Company Overview
⢠Established 1981
⢠Current Employment ~500
⢠Facilities:
⢠Plant I & II (Escanaba, MI): Precision Machining
⢠Plant III (Greenfield, IN): Assembly
⢠Product Launch Facility (Escanaba, MI): Dev. & Assy.
⢠Test Facility (Escanaba, MI)
⢠Europe Sales Manager & Distributors
⢠TS 16949 and ISO9001:2008 Certified
⢠Current OEM Customers:
⢠Caterpillar, International, Sauer Danfoss, John Deere, Cummins, DDC/Freightliner, Volvo/Mack,
Eaton, Borg Warner, NewFlyer, NABI, Gillig, Orion, Misc.
⢠Services:
⢠Thermal Systems, Electrified Components, Precision Machining, Complex Assembly, Development
from Concept to Production
⢠Key Awards:
⢠2001, 03, 04 Design News Award for Electric Pump, Advanced Filter, Electric Thermostat/Valve
⢠2001 Michigan Manufacturer of the Year, 2005 R&D Excellence in Business Award
3. April 2011Page 3 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP Manufacturing and Quality
Quality Support
⢠Precision Machining â Low & High Volume
⢠State-of-the-Art VMC, HMC & Lathes
⢠3, 4 and 5 Axis Machining
⢠Robotics for High Volume Production
⢠Dedicated Process Development Area
⢠Complex Assembly â Low & High Volume
⢠State-of-the-art Pokeoke systems
⢠Robotics for High Volume
⢠Quality System
⢠QS9000 Certified since 1998, TS in 2004
⢠Computer Based SPC
⢠CMMâs with CNC control
⢠Metallurgical Lab
4. April 2011Page 4 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
Historic Perspective: Vehicle Thermal System Programs
OEM Production Electric Cooling
System for Transit 2008
20101998
5. April 2011Page 5 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP Capabilities
Analysis Capabilities: Validation Capabilities:
⢠Mechanical/Hydraulic/Electric ⢠Vibration
⢠Primary and Secondary Systems ⢠Thermal Shock
⢠Thermal System Analysis ⢠Pressure Cycling
â˘Computation Fluid Dynamics (CFD) ⢠Corrosion
⢠Pro-E CAD ⢠Software Validation
⢠Thermal System Software Production Capabilities:
Prototype Capabilities: ⢠ISO Certified
⢠CNC Machining ⢠Assembly
⢠Sheet Metal Fabrication ⢠CNC Machining
⢠Welding ⢠Inspection
⢠Wiring harness Fabrication Proven Components
⢠Rapid Prototyping (SLS) ⢠Fans
Testing Capabilities ⢠Thermal System Controllers
⢠Heat Exchanger Performance ⢠Heat Exchangers
⢠Vehicle Fit-up ⢠Wiring Harnesses
⢠Vehicle Testing and System Calibration ⢠Temp Sensors
6. April 2011Page 6 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
Dedicated Product Launch with 31+ Engineers/Techs
Design & Analysis Prototyping
Performance Testing Validation & Reliability
Vehicle Installs & Testing
7. April 2011Page 7 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP COMPONENTS
8. April 2011Page 8 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP Components: WP29 Water Pump
FEATURES: ⢠Fully controllable or single speed
⢠High Efficiency
⢠12 or 24 Volt Models
⢠Brushless, Sensorless Motor
⢠Corrosion and Water Resistant
⢠Long Life
⢠Compact
⢠Ease of Integration
⢠Quiet
⢠CAN Capable
⢠E-Mark Certified
Controller ⢠Current Limit Protection
Specifications: ⢠Over Temp Protection
⢠Transients/Short Circuit/Reverse Battery Protection
Pump ⢠Ă1â Inlet/Outlet connection ⢠Ignition Enable
Specifications: ⢠-40 to 95° C Operating Range ⢠CAN I/O
⢠-50 to 125° C Storage Range ⢠Selectable CAN Address/Thermistor
⢠All Aluminum Outer Housing ⢠25 Amps Continuous @ 12 V, 95° C
⢠6.5 Lbs ⢠20 Amps Continuous @ 24 V, 95° C
⢠Stainless Steel Impeller ⢠9 â 32 VDC Range
⢠DTP06-4S-E003 Power Connector
⢠DTM06-6S-E007 CAN Connector
9. April 2011Page 9 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP Components: F-11 Fan and controller
FEATURES: ⢠Fully controllable or single speed
⢠High Efficiency
⢠12 or 24 Volt Models
⢠Brushless, Sensorless Motor
⢠Sealed & Fully Submersible
⢠Long Life
⢠Compact
⢠Pusher or Puller Configurations
⢠Customer Specified Lead
Lengths
⢠CAN Capable
⢠Locked Rotor Protection
⢠Finger Guard Option Available Controller ⢠Current Limit Protection
Fan Specifications: ⢠Over Temp Protection
Specifications: ⢠Ă11â Blade ⢠Transients/Short Circuit/Reverse Battery Protection
⢠-40 to 95° C Operating Range ⢠Ignition Enable
⢠-50 to 125° C Storage Range ⢠CAN I/O
⢠All Aluminum Outer Housings ⢠Selectable CAN Address/Thermistor
⢠9.0 Lbs (including controller) ⢠25 Amps Continuous @ 12 V, 95° C
⢠Glass Filled Plastic Blade ⢠20 Amps Continuous @ 24 V, 95° C
⢠20,000 Hour Life ⢠9 â 32 VDC Range
⢠Fully Reversible ⢠DTP06-4S-E003 Power Connector
⢠IP69k Rated ⢠DTM06-6S-E007 CAN Connector
10. April 2011Page 10 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP Components: FiL-11 Fan
FEATURES: ⢠Fully controllable or single speed
⢠Locked Rotor Protection
⢠Sealed & Fully Submersible
⢠12 or 24 Volt Models
⢠Brushless, Sensorless Motor
⢠Programmable Reversal
⢠Temperature Switch Input
⢠Closed Loop Temperature Control*
⢠Pusher or Puller Configurations
⢠Integrated Controller
⢠Motor and Controller Diagnostics
⢠Finger Guard Option Available
⢠E-Mark Certified Controller ⢠Current Limit Protection
Fan Specifications: ⢠Over Temp Protection
Specifications: ⢠Ă11â Blade ⢠Transients/Short Circuit/Reverse Battery Protection
⢠-40 to 95° C Operating Range ⢠Ignition Enable
⢠-50 to 125° C Storage Range ⢠EMP-Link⢠I/O
⢠All Aluminum Outer Housings ⢠Selectable EMP-Link⢠Address
⢠8.5 Lbs (including controller) ⢠PWM Input with Tach Output
⢠Glass Filled Plastic Blade ⢠25 Amps Continuous @ 12 V, 95° C
⢠20,000 Hour Life ⢠20 Amps Continuous @ 24 V, 95° C
⢠IP69k Rated ⢠9 â 32 VDC Range
* When used with uTMC or TMC ⢠Delphi Mixed MP 480/150 Connector
11. April 2011Page 11 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP Components: Thermal System Controller (TMC)
FEATURES: ⢠Controls slave controllers via; CAN, PWM, or EMP-LinkTM
⢠Capable of controlling as many as 30 components (20 E-
Link, 10 CAN)
⢠12 or 24 Volt Models
⢠Closed-loop control on 2 different temperature sensors or 1
temp and 1 pressure
⢠Configurable through CAN or EMP-LINK⢠With Service
Tool
⢠Transients/Short Circuit/Reverse Battery Protection
⢠Diagnostic Capable â Fault History
Data Storage
and Reporting: ⢠63 Histogram parameters
⢠16 Events
⢠16 Time Activities
⢠8 Accumulators
Specifications: ⢠9 â 32 VDC Range ⢠IP67 Rated
⢠-40 to 95° C Operating Range ⢠512k Flash, 32k RAM, 32k NVM Processor
⢠-50 to 125° C Storage Range ⢠DTM06-12SA-E007 Connector
⢠Duetsch Box (nylon) ⢠300 ΟA Quiescent Current Draw
⢠7.8 oz. ⢠250 mA Current Draw
12. April 2011Page 12 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP Components: Thermal System controller (TMC)
⢠Data Storage and Reporting
⢠63 Histogram Channels: % time at each
increment
â Example: fan time at each speed
⢠16 Events: counts of an event
â Example: fan turning on or off
⢠16 Time Activities: total time for a
parameter
â Example: how long a fan is on
⢠8 Accumulators: total of a parameter
â Example: total fuel used during life of
vehicle
Engine Coolant Temp Distribution
0.00%
2.00%
4.00%
6.00%
8.00%
10.00%
12.00%
14.00%
16.00%
18.00%
20.00%
75 77 79 81 83 85 87 89 91 93 95 97 99 101 103
Coolant Temp (C)
PercentofOperation
Hours Per Bus
0
500
1000
1500
2000
2500
3000
8512 8514 8515 8516 8517 8518 8519 8520
Bus Number
Hours
13. April 2011Page 13 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP Components: Micro Thermal System controller (ÎźTMC)
FEATURES: ⢠Controls slave controllers via; PWM, or EMP-
LinkTM
⢠Capable of controlling as many as 10
components
⢠12 or 24 Volt Models
⢠Closed-loop control on 2 different temperature
sensors or 1 temp and 1 pressure
⢠Configurable through EMP-LINK⢠With Service
Tool
⢠Transients/Short Circuit/Reverse Battery
Protection
⢠Diagnostic Capable â Fault History
Specifications: ⢠9 â 32 VDC Range
⢠-40 to 95° C Operating Range
⢠-50 to 125° C Storage Range ⢠62k Flash, 2k RAM
⢠Duetsch Box (nylon) ⢠DTM06-12SA-E007 Connector
⢠7.8 oz. ⢠300 ΟA Quiescent Current Draw
⢠IP67 Rated ⢠250 mA Current Draw
14. April 2011Page 14 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP Components: P450 Alternator
FEATURES: ⢠Complete Brushless Design
⢠Stationary Field Windings
⢠Aluminum Components are either A356T6
(permanent mold) or 360 (die-cast)
- Low Cu Content (corrosion resistant)
- Good Strength
- Good Thermal Conductivity
⢠Oversized full complement sealed ball
bearings
⢠Unique Lamination feature allows
improved cooling
⢠Designed for severe applications
⢠Intake air management system requires
approval
Specifications: ⢠Operational Speed: 1800 to 6500 RPM
⢠Amps: 280A @ idle, 450A @ 5000 RPM â˘Storage Temperature: -40 to 125C
⢠Turn On Speed: 1250 RPM â˘Weight: 100 lbs
⢠Rotation: CW or CCW â˘Dimension: 10.25âD x 16.00â L
â˘Ambient Temperature: -40 to 95C â˘Mount: Pad
â˘Intake Temperature: -40 to 80C â˘Negative Ground (not isolated)
15. April 2011Page 15 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP P450: 12kW Remote Power Pack (RPP)
Drive shaft from
Vehicle PTO drive
Front of
Vehicle
⢠Ideal solution for applications that
require large electrical power but no
room for additional/larger alternator
under the hood.
⢠Mounting â Bolts to the vehicleâs
frame rail behind PTO drive
Assembly or where applicable
⢠Simple and Effective â Drive Power
provided by vehicleâs Power Take Off
(PTO).
⢠Reliable â Will provide several years
of service without maintenance
⢠Corrosion Resistant â Will survive
harsh road environments; Magnesium
Chloride, Road Salt, ICE-Be-Gone,
etc.
16. April 2011Page 16 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
EMP Components: OP35/45 Oil Pump
FEATURES: ⢠Fully controllable or single speed
⢠High Efficiency
⢠12 or 24 Volt Models
⢠Brushless, Sensorless Motor
⢠Sealed & Fully Submersible
⢠Long Life
⢠Compact
⢠Customized End Cover For
Connections (Flange Mount Shown)
⢠Customer Specified Lead Lengths
⢠CAN Capable
⢠Locked Rotor Protection
Controller ⢠Current Limit Protection
Specifications: ⢠Over Temp Protection
Pump ⢠Gerotor Pumping Technology ⢠Transients/Short Circuit/Reverse Battery Protection
Specifications: ⢠3.5/4.5 Gal/min @ 80 psi ⢠Ignition Enable
⢠-20 to 100° C Operating Range ⢠CAN I/O
⢠-50 to 125° C Storage Range ⢠Selectable CAN Address/Thermistor
⢠All Cast Aluminum Outer Housings ⢠25 Amps Continuous @ 12 V, 95° C
⢠6.5 Lbs ⢠20 Amps Continuous @ 24 V, 95° C
⢠6.8â x 4.6â x 3.8â ⢠9 â 32 VDC Range
⢠TBD Hour Life ⢠DTP06-4S-E003 Power Connector
⢠Fluid Type (ATF to SAE15W-40) ⢠DTM06-6S-E007 CAN Connector
17. April 2011Page 17 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
OP35 Electric Oil Pump: BAE Hybrid Drive
18. April 2011Page 18 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
Thermal System Examples
19. April 2011Page 19 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
Mini-Hybrid for Transit Bus
ď§Application: Replaces standard hydraulic or mechanical
cooling system on Transit bus
ď§Hardware: 8 to 10 FiL-11 fans, ÎźTMC system controller,
aluminum bar/plate radiator, fabrications, air and coolant
temperature sensors and system wire harness. There is a
version for diesel, CNG and hybrid drives
ď§Functionality: The kit controls fan speeds based on a coolant
thermistor CAC air thermistor, CAN communication with vehicle,
engine and transmission (or hybrid drive) There is a built in fan
reversal and a staggered fan start for improved temperature
stability. Diagnostics are output using an LED mounted on the
kit. There is a connector for PC service tool interface for
diagnostics and calibration
ď§Benefits to Customer: Reduced noise because of variable
speed, increased fuel economy from eliminating the mechanical
fan, ambient temperature control of engine compartment,
improved temperature control of coolant increases engine
reliability, diagnostics, reduced radiator clogging because of
reversal scheme.
Summary:
20. April 2011Page 20 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
TK3/TK4 for Stationary Industrial Applications
ď§Application: General radiator applications ranging from stationary
industrial applications to vehicle primary JW cooling
ď§Hardware: 3 or 4 FiL-11 fans, ÎźTMC system controller, aluminum
bar/plate radiator, fabrications, air and coolant temperature sensors and
system wire harness. There is a version w/o the radiator available for
retrofit to existing coolers.
ď§Functionality: The kit controls fan speeds based on a coolant thermistor
and an ambient air thermistor. There is a built in fan reversal and a
staggered fan start for improved temperature stability. Diagnostics are
output using an LED mounted on the kit. There is a connector for PC
service tool interface for diagnostics and calibration
ď§Benefits to Customer: Reduced noise because of variable speed,
increased fuel economy from eliminating the mechanical fan, ambient
temperature control of engine compartment, improved temperature control
of coolant increases engine reliability, diagnostics, reduced radiator
clogging because of reversal scheme, lever vent radiator cap for safety, air
purge safety feature removes any hazardous gases from the shack prior to
maintenance
Summary:
21. April 2011Page 21 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
OK6 Oil Cooler for Hybrid Transit Bus
ď§Application: Electronics cooling on Allison
Hybrid Transit bus application
ď§Hardware: 6 FiL-11 fans, ÎźTMC system
controller, aluminum bar/plate oil cooler,
fabrications, oil temperature sensor and system
wire harness
ď§Functionality: The kit controls fan speeds
based on an oil thermistor. There is a staggered
fan start for improved temperature stability and
reduced fan cycling in cold weather.
Diagnostics are output using an LED mounted
on the dash of the bus. The EMP link from the
ÎźTMC is routed to the rear 9 pin connector for
PC service tool interface
ď§Benefits to Customer: Reduced noise
because of variable speed, staggered fan start
results in reduced fan cycling and improved
temperature control, diagnostic output from LED
and PC tool ensures that nobody has to crawl
on the roof to check functionality of the kit
Summary:
22. April 2011Page 22 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
Motor and Electronics Cooling for BAE Transit Bus Hybrid Drive
ď§Application: Cooling of electronics and drive system
for BAE Series Hybrid Applications
ď§Hardware: 2 FiL-11 fans, WP29 water pump (with
CM20 board), aluminum bar/plate heat exchanger,
degas bottle, coolant temperature sensor, level sense
switch and system wire harness
ď§Functionality: The kit reads in the coolant
temperature via the WP29 pump. This temperature is
broadcast via J1939 to the customer who then tells the
pump what speed to run via J1939. The customer also
controls the fan speed using PWM input and monitors
the fan speed using speed feedback output. There is
an active degas system contained in the kit and a float
switch to tell the customer when the fluid level is low.
ď§Benefits to Customer: Precise temperature control
using variable speed WP29 and FiL-11, accurate
temperature measurement and reporting via J1939,
high heat rejection for a small package size, degas loop
simplifies filling procedure, 16 psi pressure cap ensures
adequate cooling at higher elevations (possible
because of fabricated degas bottle)
Summary:
23. April 2011Page 23 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
OK1/OK2 Oil Coolers for Transmission and Hydraulic Cooling
ď§Application: Engine, Transmission and Hydraulic Oil cooling
ď§Hardware: F-11 fan(s), aluminum bar/plate heat exchanger, fabricated
shroud, coolant temperature sensor, C20/CM20 controller(s) and system
wire harness
ď§Functionality: The kit reads in the oil temperature via the CM20
controller. This temperature can be broadcast via J1939. The fan speed
is controlled based of the oil temperature. There is a reverse at startup
and also a timed reversal to prevent clogging
ď§Benefits to Customer: Precise temperature control using variable
speed fans, accurate temperature measurement and reporting via
J1939, high heat rejection for a small package size, built in bypass to
protect the core during cold weather, reversal routine has helped reduce
downtime for heat exchanger cleaning in forestry equipment
Summary:
24. April 2011Page 24 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
TK1 for Electronics and Aux Engine Cooling
ď§Application: Hybrid electronics cooling, engine auxiliary cooling
ď§Hardware: F-11 fan, WP29 pump, high performance aluminum tube/fin heat
exchanger, fabricated shroud, coolant temperature sensor, CM20 controller,
degas bottle and system wire harness
ď§Functionality: The kit reads in the coolant temperature via the CM20
controller. The fans speed is controlled based of the coolant temperature. The
WP29 is On/Off. There are some versions of the kit that use SPAL fans for
on/off operation
ď§Benefits to Customer: Precise temperature control using variable speed
fan, high heat rejection for a small package size, high flow in restrictive
systems from WP29 pump, options for installation hardware, degas bottles,
etc
Summary:
25. April 2011Page 25 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
Mack/Volvo Refuse Vehicle Auxiliary Cooler
ď§Application: Auxiliary JW cooling of high horsepower cab over refuse
vehicles
ď§Hardware: F-11 fans, fabricated shroud, C20 controllers
ď§Functionality: The C20 controllers monitor the engine coolant
temperature via J1939. The fans turn on/off based on the J1939
temperature. The 2007 application only turns this cooler on as a last
resort when coolant temperature is above a certain temp. For the next
generation, variable speed is being considered
ď§Benefits to Customer: The customer needed high airflow to provide
the auxiliary cooling for 2007 engine. The J1939 communication made a
clean install. For the next generation, variable speed is being
considered to help keep the main engine fan off for noise reduction and
possible slight fuel economy gains. Keeping the main engine fan off will
also keep the cabs warmer in the winter because the mechanical fan
sucks the heat out of the cab when it runs. The next generation may
switch to FiL-11 for cost savings.
Summary:
26. April 2011Page 26 EMP PROPRIETARY INFORMATION
Copyright Š 2009 EMP | 2701 N 30th
St. Escanaba, MI 49829 (906)-789-7497 | www.emp-corp.com
Over the Road Truck Remote AC System
ď§Application: Remote AC kit used for over the road trucks
with sleeper cabs
ď§Hardware: 2 12V FiL-11 fans, 2 AC condensers, fabricated
shroud, TMC controller, system wire harness
ď§Functionality: The FiL-11 fans are controlled using
pressure sensors located on each condenser outlet line. The
TMC takes in both pressures and determines which fan runs
and the speed the fan runs.
ď§Benefits to Customer: Fuel economy is the key driver for
this test. PACCAR measured 75% reduction in mechanical
fan run time at idle and 23% reduction in mechanical fan run
time using the Wal-Mart specific urban drive cycle. The heat
rejection of the engine cooling pack was improved by
offloading the AC requirements. The reduction in mechanical
fan operation reduced the noise produced. The variable
speed FiL-11 fans also reduced the noise produced by the
APU condenser fan compared to the on/off brushed fan that
was previously run full speed whenever the compressor was
running.
Summary: