Note: Refer HERE for an explanation of Closed Loop Lambda Control.
The following options are available:
·Stoich Mode (Narrow Band) - Given a target oxygen sensor voltage (Dither Voltage) the ECU will progressively increase the CLL Fuel Correction when the oxygen sensor reads lean and progressively decrease the CLL Fuel Correction when the oxygen sensor reads rich. This results in the AFR continuously oscillating around the target Dither Voltage, this is known as dithering and is often required for correct catalytic converter operation. In this mode CLL is typically set up to operate only under cruise and light load conditions. This is the only mode that supports use of narrow band oxygen sensors.
·Stoich Mode (Wide Band) - Given an AFR/Lambda Target (from the AFR/Lambda Target Table), the ECU will progressively increase the CLL Fuel Correction when the oxygen sensor reads lean and progressively decrease the CLL Fuel Correction when the oxygen sensor reads rich. This results in the AFR/Lambda continuously oscillating around the target point, this is known as dithering and is often required for correct catalytic converter operation. In this mode CLL is typically set up to operate only under cruise and light load conditions.
·Auto Mode (Wide Band) - Given an AFR/Lambda Target (from the AFR/Lambda Target Table), the ECU will use a closed loop control algorithm to calculate the immediate CLL Fuel Correction required. This method provides a fast and stable correction especially when the difference between the target and actual AFR is large. This mode is recommended when suing Wideband Sensors as it can react faster and more accurately than Stoich Mode (Wide Band).
This setting prevents CLL from operating below a particular engine coolant temperature. This avoids having CLL active while warm up enrichment is still being added. Typically this value is set to about 5 degrees below the normal operating temperature.
The length of time after engine start up that CLL is prevented from running. This setting is used to ensure that all startup enrichments are inactive and that the oxygen sensor is up to temperature before CLL is enabled.
RPM Lockout Low & RPM Lockout High
This setting prevents CLL from operating outside of a particular engine speed range. Typically the RPM Lockout Low will be set well below the idle RPM to ensure CLL is active at idle but in some applications the target AFR can result in an unstable idle, in this case set RPM Lockout Low well above the idle RPM.
This setting prevents CLL from operating above a particular MAP value. This allows CLL to be disabled when the engine is under higher loads, a typical value is about 70 kPa.
Selects whether Trim limit Max & Trim Limit Min or the CLL Positive Trim Limit & CLL Negative Trim Limit Tables are used to limit the fuel trims.
Setting this to 3D also sets the Update Rate Table to 3D.
Trim Limit Max & Trim Limit Min
These settings allow the user to set the maximum and minimum Fuel trim that can be applied. Typical values would be 15% and -15%.
Sets the rate at which fuel trim is increased/decreased. Too large of a gain value will result in large swings around the target and too small of a gain will result in very slow corrections. A typical gain value is 2.
This setting is only available when Lambda Mode is set to Stoich Mode (Narrow Band) or Stoich Mode (Wide Band).
Allows the number of banks. If set to 1 then all cylinders are trimmed the same amount, if set to 2 banks then two oxygen sensors are used so that each bank can be trimmed independently.
2 Bank mode can be used on engines with only one bank if the exhaust system is setup such that each oxygen sensor only receives exhaust gas from its own distinct group of cylinders. For example the RB26DETT could use one sensor in each downpipe to control each half of the engine's cll trim independently.
NB Oxy Source & NB Oxy Source 2
These settings allow the user to select the input that the narrow band oxygen sensor(s) are connected to.
These settings are only available when Lambda Mode is set to Stoich Mode (Narrow Band) and NB Oxy Source 2 is only available when Number of Banks is set to 2.
These settings allow the user to select the Lambda input for each of the banks being controlled. Select the Lambda source that gives the best average reading for its bank.
These settings are only available when Lambda Mode is set to Stoich Mode (Wide Band) or Auto Mode (Wide Band) and Bank 2 Source is only available when Number of Banks is set to 2.
The Dither Voltage is the voltage output by the narrow band oxygen sensor at the stoichiometric point (AFR 14.7:1 for pump fuel). This value is typically set to 0.45 Volt.
This setting is only available when Lambda Mode is set to Stoich Mode (Narrow Band).
Used to allocate cylinders to either Bank 1 or Bank 2. The trim is applied per injector driver so when in sequential or sequential staged mode it is per cylinder but when in group mode a single table or cell can affect multiple cylinders depending on the injector locations.
This setting prevents CLL from operating above a specific TPS(Main) value, this allows CLL to be disabled under heavy throttle. A typical value is about 75%.
This setting prevents CLL from operating above a specific TPS Delta (Rate of Change) value, this allows CLL to be disabled under transient throttle.
A value of 0 turns off this lockout.
This setting prevents CLL from operating above a specific MAP Delta (Rate of Change) value, this allows CLL to be disabled under transient load. A typical value is about 4kPa.
A value of 0 turns off this lockout.
Controls the rate (how many times per second) at which the closed loop fuel correction is calculated at various RPM points, this allows the control to operate more or less frequently based on the engine speed.
This setting is only available when Lambda Mode is set to Auto Mode (Wide Band).
Note: This table can optionally be made 3D with configurable axes by setting Trim Limit Tables to 3D.
Closed Loop Gain Control Table
Sets the gain (sensitivity) of the closed loop control algorithm at various Lambda Error values, this allows larger corrections to be made when the Lambda Error is large and smaller corrections to be made when the Lambda Error is small. Excessively large numbers in this table will result in oscillation around the Lambda Target. Excessively small numbers will result in a slow response.
This setting is only available when Lambda Mode is set to Auto Mode (Wide Band).
CLL Positive Trim Limit & CLL Negative Limit Tables
These tables act in the same manner as the Trim Limit High & Trim Limit Low settings with the added functionality of being able to change the trim limits based on two other variables.