Air-Fuel Ratio Control

Please also refer to HEINZMANN's >> Gas Engine Management Catalogue for details on all AFR components and systems.

Positioners for AFR Control

Whether low calorific gases or high-precision dosing requirements, these positioners are perfectly suited to be implemented into an existing AFR control system. Independent of gas type or communication requirements, the annular gap gas mixers and the electronically controlled gas positioners, both equipped with SMC stepper motor controllers, are designed for a wide range of applications and communicate via different analogue input signals and/or several CAN protocols.

Component Description Documents
annular gap gas mixer for AFR
GMA 30 - 49
annular gap gas mixer for AFR
GMA 58 - 75
annular gap gas mixer for AFR
GMA 82 - 100

Annular gap gas mixers for precise adjustment of the air/gas ratio, suitable for various types of gas (natural gas, biogas, waste dump gas, propane). The venturi-shaped nozzle design guarantees only minimal pressure losses and a homogenous air/gas mixture over the speed and load range.
Suitable for lean-burn engines

Data Sheet

adjusting screw E-LES-30 SMC
FR E LES LC 50 0680 0218E-LES 50 SMC adjusting screw E-LES 80 SMC

Electronically controlled gas positioners with high-resolution stepper motor for precise adjustment of gas dosing, featuring an optimised V-shape design and special coating. Operating with  any gas type, quality and suitable for integration into existing AFR control systems on engines up to 1750 kW.

Data Sheet


KRONOS AFR-Systems and Components

The four different KRONOS AFR systems for control of air-fuel ratio are each designed for a specific range of applications. Their proven mechanical and electronic components guarantee an optimal engine performance and a long operating life. Both highly adaptable to engine-specific requirements and compatible with third-party components, KRONOS systems offer an excellent solution for AFR control in gas and dual-fuel engines. 

Please use the order information sheet to provide application-specific information when inquiring about KRONOS AFR systems.


System Description Applications Documents

KRONOS 10 Control System for AFR

Mechanical air-fuel ratio control 

consisting of a throttle valve, a Venturi based gas/air mixer and a mechanical gas main adjusting screw.

Engines from 25 kW to 3 MW where precise control of emissions is not required

ATEX certified


KRONOS 20 Control System for AFR

Electronical air-fuel ratio control, allowing speed/load dependent lambda values to be set within a certain range

Advantage: Improved engine behaviour under all operating conditions

Engines in rich and lean operation with higher emission quality requirements

ATEX and CSA certified


E-LES 30/50/80 LC

Compact solution for AFR control. E-LES LC is situated in the gas line after the zero pressure regulator and connected to a gas mixer. The control unit integrated in the device controls uses the voltage signal of a lambda probe to determine the actual gas requirement.

Middle-sized engines in rich operation with higher emission quality requirements


KRONOS 30 Control System for AFR

Full authority control system for AFR, modular concept can be extended to accommodate applications with larger variations in gas, engine and ambient parameters.

Engines from 200 kW to 3 MW multi-gas, low and high gas quality or lambda fluctuations

KRONOS 40 Control System for AFR

Injection based control system performing AFR and speed/load control with electrically actuated gas admission valves controlled by solenoids.
Advantage: Individual cylinder injection and exhaust gas temperature sensing allow precise gas metering.

Lean-burn engines with cylinder outputs from 100 kW to 1 MW per cylinder and up to 20 cylinders