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E-Fan Systems

The Smart Flow® e-fan cooling system replaces outdated mechanical cooling systems for engine/vehicle cooling. It has become the standard cooling system used by transit bus manufacturers in North America.

The e-fan system is also ideal for retrofitting/refurbishing existing fleets. Benefits include…

  • Better fuel economy
  • Lower maintenance costs
  • Improved safety
  • Increased up-time
  • Improved emissions
  • More power to the wheels
Custom Configurations

SmartFlow® e-fan systems can be configured to allow for simple installation on most vehicles. Units are available in both pusher and puller configurations to maximize mounting location adaptability. Control strategy can be configured as:

  • Heat exchanger allocation
  • Fan speed default and set points
  • Fan off for engine warmup
  • Fan reverse (cleanout)
  • Engine compartment temperature control
  • External fan speed request
  • Temperature set points (thermistor or J1939 input)
  • Customizable for specialty features

E-fan systems feature the EMP designed-and-built 11″ and 15″ fans.

These brushless DC fans have features that set them apart in the market.

  • Variable speed
  • Full reversibility
  • Cast aluminum shroud designed to withstand the harshest environments
  • Complete diagnostics and service support

Learn more about our fans HERE.


Heat exchangers on our series of cooling systems are designed for severe duty applications, with aluminum bar-plate construction cores, cast aluminum welded on tanks, and non-louvered wave fins optimized for the EMP fans. The heat exchangers are uniquely mounted to allow for servicing without having to remove the entire cooling system. They also include non-louvered fins to reduce clogging.

All of our e-fan systems contain an integrated wiring harness assembly which features:

  • Harness materials selected for automotive/heavy equipment environments
  • Built-in fan addressing
  • Connectors are IP69k rated
  • Terminals crimp per SAE/CAR-21
  • EMPs thermal management controller (TMC) interfaces with J1939
  • EMP Link (LIN/ISO) used for fan communication to EMP’s TMC
  • External connections include power, ground, ignition, J1939 CAN, with optional diagnostic LED and manual reverse switch

All e-fan cooling systems are custom designed for specific vehicle applications.

  • Welded steel, durable powder coated frame assembly
  • Aluminum bar/plate heat exchangers
  • Redundancies in the fan array to withstand an individual downed fan
  • Qualified to 185 unique validation procedures to production launch
  • IP69k rated

All of our e-fan systems utilize patented individual fan baffles for airflow management during regular operation. These baffles provide means for individual fan control, redundancies, and sequential start up for greater cooling control in both hot and cold temperatures.

Our cooling systems include an EMP thermal management controller (TMC) with hardware/software designed in house.

The TMC receives inputs from sensors, engine, transmission, hybrid drive, and vehicle. It uses multiple algorithms to interpret inputs and provides optimal thermal control to the system and complete system diagnostics.

In the event that vehicle communication is unavailable, all e-fan cooling systems are designed with a fail-safe mode featuring a pre-programed default speed to allow the vehicle to continue operation. The EMP TMC diagnostics will log the event for troubleshooting.

The EMP TMC system controller monitors vehicle speed to reduce fan RPM when the vehicle is stopped or at low speed conditions to reduce noise. All cooling parameters continue to be monitored to blend engine/transmission/hybrid drive temperature protection with the “curbside quiet” algorithm.

Air flow can be reversed periodically as a part of routine vehicle maintenance. This helps keep the heat exchanger cooling fins free of debris and functioning properly. Fan reverse can be controlled by a manual push button, as a timed event, by ignition on, or by J1939 request.

Fans on our series of cooling systems are individually speed controlled by the EMP TMC system controller. This allows for optimal thermal management, supports specialized features and helps to prevent heat exchanger clogging in dirty environments.

On e-fan cooling systems, the system controller receives and interprets temperature (i.e. engine coolant, intake manifold, and oil) sensor feedback via CAN J1939 and drives the fans as necessary to maintain optimal temperatures. This eliminates overheating and overcooling due to changes in ambient temperature and cooling demand.

  • Unique calibrations for each engine/transmission combination.
  • Individual fan control.
  • Radiator, CAC, Trans cooler individual strategies.

Sequential fan startup up.

All systems are compatible with:

  • Telematics
  • 12V and 24V
  • EMPower Connect Service Tool using common RP1210 compliant data link adapters (examples: Cummins inline, Nexiq, etc.)
  • J1939 CAN
    • 250k baud fixed
    • 500k baud fixed
    • 1M baud fixed
    • Auto detect baud rate
    • Supports messages for Secondary OBD Device

E-fan systems utilize in house developed proprietary service tool. Includes:

  • EMPower Connect
    • Diagnostics
    • Real time dashboard
    • History download
    • Real time data logger
    • Active/Inactive faults
  • EMProgram
    • Field calibration software updates
    • Field base software updates
    • Failsafe reflash ensured by bootloader software
  • History Analysis Tool (HAT)
    • Analyze history data captured with EMPower Connect
  • Data Analysis Tool (DAT)
    • Analyze real time data captured with EMPower Connect
  • Field refurb programming and test station available
  • EMP J1939 Bus Monitor (CAN sniffer) available for root cause analysis

All EMP e-fan systems include free software for diagnostics as well as history data collection. There are regional service representatives in place for onsite support and training as well as on-line training available for mechanics and technicians.

Aluminum Bar/Plate Heat Exchanger
Aluminum Fans with Plastic Finger Guard
Steel Monocoque Structure
9-18 VDC
18-32 VDC
215 - 315 Amps (280 - 450 HP engines)
12,000 to 18,000 CFM
Up to 120 GPM
-40° to 130° F
-58° to 221° F
Dimensions based on custom system configuration
300 to 500 lbs
E-Fan Systems Diagram