TMF Idle Speed Control

For idle speed control, users often try to manage engine speed by manipulating throttle position to control airflow. This works reasonably well with solenoid systems (ICV), where position has a more proportional effect on airflow.

With DBW — especially on larger throttles — small changes in throttle position have a disproportionately large effect on airflow, making fine control difficult. Emtron addresses this with a purpose-built approach.

TMF (Throttle Mass Flow) Idle Speed Control is a specialised function that provides superior airflow control at idle by working directly in mass flow terms rather than raw position.

Initial Position

The concept is straightforward: the airflow required to idle the engine is mapped and controlled directly. The Initial Position table defines target airflow (g/s) based on XY parameters.

A PID loop can be enabled for adaptation, just as with traditional idle systems. Because the PID output is airflow rather than raw position, it has greater authority and precision.

Throttle Body Model

The target air mass is translated to a DBW servo position via the Throttle Body Model, which should be validated before relying on TMF idle control.

Regardless of whether the Throttle Body Model is used as part of the engine’s airflow model, TMF Idle Speed Control uses the TMF calculation to determine DBW position.

Idle Ignition Control

TMF Idle Speed Control should be treated as the base air delivery system. Idle Ignition Control handles fine idle speed corrections, as ignition timing has a fast and predictable effect on engine torque at low RPM.

The Emtron Idle Ignition Control is a comprehensive system with full PID controls. When used together with TMF Idle Speed Control, it delivers OEM-level idle quality on virtually any application.