Search RomRaider





  • View Page
  • Page History/Versions
  • Print Page

Delta-Load Fueling Compensation

This is highly experimental.

(If it proves to be accurate, it will be added to the official ROM definitions.)

What follows is a condensed version of this thread in the ECU analysis forum.

The ECU’s calculation of “Final Fueling Base” contains a few compensations that are added to the primary fueling enrichment. One of those compensations, here dubbed Delta-Load Compensation, or “DLC,” is responsible for an excessively rich condition during spoolup.

The DLC parameter itself is calculated from four input parameters:

Input AChange in load since the previous iteration (low-pass filtered)
Input BChange in load in the previous two iterations (clamped between −0.2 and +0.2)
Input CThis is a function of input B and two or three tables, see below.
Input DThis is a function of input A, one of two scalars, and a table.

Input A is multiplied by another value to become Input D. That ‘other value’ may be 0.1, 0.03125, or a value that depends on RPM. The conditions that determine the multiplier have not yet been studied.

Input B is turned into Input C through a series of operations, starting with the “Delta-Load Sigmoid” table, shown here…

The transformed Input B is then scaled by one or both of the tables shown below. The table on the left is always used; the table on the right is applied when load is falling rather than rising. The tables are “DeltaLoad Input C Rising Load Compensation” and “DeltaLoad Input C Falling Load Compensation” respectively.

Inputs C and D are each scaled by Engine Coolant Temperature (ECT) activation tables, and the resulting values are added together to get the delta-load compensation:

DeltaLoad Compensation = (InputD * InputD_Activation) + (InputC * InputC_Activation)

InputC_Activation is strictly a function of ECT, and there are separate tables for rising load and falling load (rising is on the left in the picture below).

InputD_Activation also has rising-load and falling-load activation tables. The rising-load activation table is a function of both ECT and load (grams of air per combustion charge). The falling-load activation table is a function of ECT alone.

The ECT axes on the tables below are in Celsius.


RomRaider Forums

Join our forums, the best place to find help and answers!


RomRaider is developed and supported by volunteers working on their own time. To support their efforts please consider making a donation.

Page last modified on August 23, 2011, at 02:43 AM
Powered by PmWiki