Rich-Burn Air/Fuel Ratio Control System

The AFR-9R is the right choice when searching for the simplest to use load following air/fuel ratio control system. The system is designed to maximize the efficiency of a three-way catalyst by maintaining the proper air/fuel ratio over varying engine loads, speeds, fuel quality, ambient temperatures and barometric pressure. This is done without operator intervention after the initial program setup.

  • Set point and operation done entirely through the full-color graphic display, enclosure or remote mounted
  • Designed for wide range of horsepower, gas fueled, carbureted rich-burn engines
  • Microprocessor-based controller with nine air/fuel set points
  • Available with either the non-intrusive fuel enrichment strategy or the in-line fuel authority control strategy
  • High-speed full authority butterfly fuel control valves for quick response time (available)

FW Murphy Production Controls offers support for all our products. If you are unable to find the product that you need, please call us at 918-957-1000.

  • Overview
  • Specifications
  • Literature

The AFR-9R features nine set point targets based on a combination of three RPM settings and three manifold pressure settings and includes three valve default position settings. As your engine’s load and/or speed change, the AFR-9R anticipates (feed-forward control) and corrects the air/fuel ratio to optimize catalyst performance.

The system includes the PV450 full-color graphical user interface for control functions, monitoring, programming and diagnostic displays. The eight-button display includes comprehensive built-in help files for added operator convenience.

The FW Murphy AFR-9R air/fuel ratio controller represents cutting-edge technology in many areas: hardware, microprocessor power, control system software, operator interface options, adaptability to variable engine conditions and control requirements, software upgrade capability, in addition to comprehensive onboard diagnostics system (OBD).

  • Proportional solenoid fuel control valves for auxiliary fuel control (available)
  • Map sensor to measure variances in manifold air pressure
  • Post catalyst, oxygen sensor input for real-time adaptation to changing catalyst performance (post catalyst sensor is optional)
  • Pre and Post catalyst differential temperature displayed when using an (optional) ungrounded Type K thermocouple
  • Separate alarm and shut-down dry-contact relays for flexibility in setup and operation
  • Heated exhaust gas oxygen sensors for optimum Air/ Fuel Ratio control
  • 12 / 24 VDC Nominal
  • Magnetic pickup or CD ignition input for engine speed operating reference
  • Upgradeable to accept additional end devices
  • IP 66 enclosure, 10 in. W x 13 in. H x 5 in. D

For more information about this product, you can download the related literature here:

Note: Software, manuals and files for this product are only available on the Emissions Controls products extranet. (Assigned username and password required.)


Sales Bulletin (0910477; revision date – 09/2020)

Important USB Information AFR with PV450 (1815242; revision date – 06/2018)


Brochure (1611996; revision date: 11/2022)