Product of the Month: AFR 200 Series Controllers

The Air Fuel Ratio (AFR) 200 series controllers provide a comprehensive fuel management system for gaseous-fueled, spark-ignited engines which incorporates a wide range of gaseous fueled engines ranging from 1 L to 13 L+.  The AFR’s fuel control algorithm maintains a stoichiometric or lean-burn air-fuel ratio for optimized engine performance. Engine speed can be governed in either isochronous or droop modes using GAC’s proprietary Electronic Digital Governor (EDG) algorithm. The AFR offers:

  • Optimal closed loop air-fuel ratio and delivery control
  • Actuator throttle body control
  • Integrated EDGe governing
    • 3 fixed speed +Droop
    • 1 Variable Speed +Droop
    • Multi-PID across Speed / Load Range
    • Load Sharing & Synchronizing (AUX) Input
    • Dither and MAX Fuel Alert
  • Air Fuel System Tuning Tables
    • Fuel P/I
    • O2 Setpoints Stepper
    • Multi-PID across speed / load range
  • Engine sensor and data monitoring with LED display and blink code for use when a computer is not available.
  • CAN / serial communication
  • Connector, harness and cast aluminum case are environmentally sealed to IP-67.
  • Ruggedly designed, highly reliable and includes protection against reverse battery voltage, transient voltages, short circuits and loss of engine speed sensor signal or battery supply.
  • Easy configuration and customization using GAC’s SmartVU software including diagnostic and troubleshooting functionality, available free for download on the GAC website.

The AFR system is capable of supporting the strict emission regulations of the USA and Europe as well as the rest of the world.

Depending on the AFR version selected, the following sensor inputs are supported for added control and engine protection:

  • Second (post-catalytic) oxygen sensor
  • Engine Oil Pressure (EOP) sensor
  • Engine Coolant Temperature (ECT) sensor
  • Exhaust Gas Temperature (EGT) sensor; Type K thermocouple


Application of the Month

The GAC Air Fuel Ratio (AFR) – ATB solution provides closed loop, air-fuel ratio control with an integrated venturi mixer / control valve for low pressure gaseous fueled engines, providing the control you need for any engine based generator power solution. 

GACs comprehensive fuel management system for gaseous-fueled, spark-ignited engines ranging from 1 L to 13 L+ is a total system approach, providing a cost effective solution with the greatest potential for improvement in engine efficiency and exhaust emissions.  The air-fuel mixture is constantly adjusted between lean/rich, to operate at peak efficiency and minimize emissions using the AFRs feedback / predictive algorithm and customizable PIDs settings.

The AFR controller works alongside the GAC actuator throttle body (ATB). ATBs feature a spring return butterfly valve for safety and its maintenance free design, precision bearings, and idle air adjustment screws make it the perfect solution for use in the harshest environments, ensuring a long life.

GAC ATBs are available in a host of bore sizes to fit most engines, from 25 mm to 95 mm.

The ATB Series integral throttle body electric actuators are designed to control the air or air/fuel mixture to a gas or gaseous-fueled engine working in tandem with a conventional fuel mixer.

  • Cost-effective, maintenance-free, compact design
  • Rapid response to transient load condition
  • Sealed to 5.0 bar
  • Mounts in any position; no mechanical linkage, no mounting brackets
  • Flexible design for engine, manifold, and fuel mixer considerations
  • Idle and max adjustment screws
  • Optional high temperature and corrosive environmental conditions

Using GAC SmartVU software the system allows for customizable, easy-to-use, quick turnaround for modifications and changes.

GAC Magnetic Speed Sensors (MAG Pickup) are used to calculate crankshaft revolutions per minute (RPM) via the input flywheel teeth value within the AFR.   

A Zero Pressure Gas Regulator is attached to the fuel inlet port on the mixer / fuel control valve assembly to regulate the pressure / flow to the assembly. While an electronic gas lockout valve increases safety and performance.  Additional tools can be used to filter exhaust, detect O2 levels, monitor oil pressure and coolant temperatures to ensure safe and constant operation.

The overall low pressure design is perfect for applications using Shale gas, Digester gas, Biogas, Landfill gas, Wellhead gas, Coalbed/seam gas.

Aged to Perfection

One of GACs most common testimonials is “ I can set it up and it runs forever!” Well recently a 25 year old unit stopped running. 

After one of GAC support engineers diagnosed the problem, a loose connector rod, the controller is back to work at its Hickory Hill Greenhouse location is this ADC225 running a gen-set using a propane fueled Ford 2.3L Katolight Gen Set.

Here’s to another 25 years providing excellent speed control and load response!

Item of the Month : AFR Lean Burn Adapter

This simple to install plug an play adapter uses Bosch LSU4.2 sensor technology replaces your narrow band sensor to optimize for emmisions.

The GAC KT317WB-AFR ready-to-use Lean Burn Adapter kit for use with AFR200 Series Controllers determines how rich or lean an engine is running at any load and compensates for changes in temperature and sensor condition.

Performance and operational settings are adjusted and viewed in real time using GAC’s SmartVu software. Set the Adjustment table in SmartVu to the required Lambda at speed vs load condition and you are done.