Now, lets go for a typical highway cruise, at about 65mph, on a nice flat road: The value contained in that cell is adjusted with the Integrator values (which change based on O2 readings, etc.). Since the RPM is very low and the MAF is very low, the car will be using the information in BLM Cell 0 to adjust the idle fuel mixture. Let's say the car is sitting in the driveway in Park, up to temperature, and just idling.
So, the cell being accessed at any given point in time is controlled by airflow versus rpm. The individual cells are numbered 0 through 15 (for a total of 16 cells). As you can see, it is offset by rpm in the columns, and by airflow in the rows. The table above depicts the BLM cell table that is held in the typical Turbo Regal ECM. For both the Integrator and BLM values, a higher value represents a correction that adds fuel to the fuel mixture, due to higher injector pulse widths. Each BLM value in turn contains an integrator value (also from 0 to 255), which is a short term fuel correction based on immediate operating conditions. Each cell contains a Block Learn Multiplier (BLM) value (from 0 to 255), which represents a long-term fuel correction based on that cell's operating conditions over a relatively long period of time. The fuel delivery strategy uses a two dimensional table that has four rows and four columns, for a total of 16 "cells". In our ECM the Long Term fuel adjustment (BLM) happens about twice per second, while the Short Term fuel adjustment (INT) happens about 20 times per second Basically, these two strategies are used to make adjustments and adaptations to the ever changing loads, atmospheric conditions, and fuel quality to keep the car's air/fuel ratio correct for driveability and emissions.Īlso, keep in mind that when we say Long Term or Short Term, we are talking in computer time, not human time. The Integrator is the same idea, only for short term adjustments. In a nutshell, the Block Learn Multiplier (BLM) is the long term fuel adjustment that the ECM "learns" to keep the air/fuel ratio within acceptable parameters.
0 kommentar(er)
