BMW_Adaptation.pdf

Adaptation Values

• In order to maintain an "ideal" air/fuel ratio, the engine control module is capable of

adapting to various environmental conditions encountered while the vehicle is in

operation (i.e. changes in altitude, humidity, ambient temperature, fuel quality, etc.).

• The adaptation system can only make slight corrections and can not compensate for

large changes which may be encountered as a result of incorrect airflow or incorrect

fuel supply to the engine.

• Within the areas of adjustable adaption, the engine control module modifies the

injection rate under two areas of engine operation:

1. During idle and low load mid range engine speeds (Additive Adaptation),

2. During operation under a normal to higher load when at higher engine speeds

(Multlplicative Adaptation).

These values are displayed in the "Diagnosis Requests" section of the DIS software and

is a helpful diagnostic toot that shows how the system is trying to compensate for a

less than ideal initial air/fuel ratio.

NOTE: If the adaptation value is greater than "0.0 ms" the Engine control module is trying

to en-richen the mixture. if the adaptation value is less then "0.0 ms the .Engine Control

Module is trying to lean-out the mixture.

Diagnosis Request Status Explanation

Additive mixture If the value is greater than 0.2 ms there is an unmetered air leak

adaptation (idle) or not enough fuel being supplied to the system.

• The O sensor indicates a LEAN condition

• The engine control module tries to RICHEN the mixture.

If the value is less than -0.2 ms there is an air restriction or too

much fuel is being supplied to the system.

• The 02 sensor indicates a RICH condition

• The engine control module tries to LEAN out.the mixture.

Multiplicative mixture If the value is greater than 8 % there is an unmetered air leak or

km (Part Load) nott enough fuel being supplied to the system.

• The 02 Sensor indi .a es a LAN condition

• The engine control module tries to RICHEN the mixture.

If the value is less than -8 % there is an air restriction or too

much fuel being supplied to the system.

• The 02 sensor indicates a RICH condition

• The engine control module tries to LEAN out the mixture.

OBD 11 Fuel System Monitoring - 2

Alternate or Equivalent Phase-in: Phase in of equivalent emission reductions by the

end of the last year of the scheduled phase-in.

The emission reductions are calculated by multiplying the percent of vehicles (based on the

manufacturer's projected sales volume of all vehicles and engines) meeting the new

requirements per year by the number of years implemented prior to and including the last

year of the scheduled phase-in and then summing these yearly results to determine a

cumulative total.

Base Fuel Schedule: refers to the fuel calibration schedule programmed into the

Powertrain Control Module or PROM when manufactured or when updated by some

offboard source, prior to any learned on-board correction.

Catalyst Monitoring:

Non-Low Emission Vehicles: The catalyst system shall be considered malfunctioning

when its conversion capability decreases to the point that HC emissions increase by more

than 1.5 times the standard over an FTP test from a test run with a representative 4000

mile catalyst system.

Transitional Low Emission Vehicles TLE1h these vehicles shall employ an emission

threshold malfunction criterion of 2.0 times the applicable FTP HC standard plus the

emissions from a test run with a representative 4000 mile catalyst system.

Low Emission Vehicles LEV: The catalyst system shall be considered malfunctioning

when its conversion capability decreases to the point that either of the following occurs:

1. Hydrocarbon (HC) emissions exceed the applicable emission threshold specified. The

emission threshold criterion for LEV and ULEV applications shall be 2.5 and 3.0 times

the applicable FTP HC standard, respectively, plus the emission level with a

representative 4000 mite catalyst system. Notwithstanding, beginning with the 1998

model year, manufacturers shall phase in an emission threshold of 1.75 times the

applicable FTP HC standard for all categories of low emission vehicles, which shall not

include the emission level with a 4000 mile catalyst system.

Federal Test Procedure (FTP): a specific driving cycle that is utilized by the EPA to test light duty

vehicles and light duty truck emissions. As part of the procedure for a vehicle manufacturer to obtain

emission certification for a particular model/engine family the manufacturer must demonstrate that

the vehicles) can pass the FTP defined driving cycle two consecutive times while monitoring various

components/systems.

Some of the components/systems must be monitored either once per driving cycle or continuously.

Components/systems required to be mon- Components/systems required to be moni

itor once within one driving cycle: tored continuously.

Oxygen Oxygen Sensors • Misfire detection

r Secondary Air Injection System • Fuel system

• Catalyst Efficiency • Oxygen Sensors

• Evaporative Vapor Recovery System • All emissions related systems providing or

receiving signals to the DME, EGS, or EML.

NOTE: Due to the complexity involved in meeting the test criteria within the FTP defined driving

cycle, all tests may not be completed within one "customer driving cycle". The test can be

successfully completed within the FTP defined criteria, however customer driving styles may- differ

and therefore may not always monitor all involved components/systems in one "trip".

Fuel trim: refers to feedback adfustments to the base fuel schedule. Short-term fuel trim refers to

dynamic or instantaneous adjustments. Long-term fuel trim refers to much more gradual

adjustments to the fuel calibration schedule than short-term trim adjustments. These long terror

adjustments compensate for vehicie differences and gradual changes that occur over time.

Functional check: for an output component means verification of proper response to a cuter

command. For an input component, functional check means ve 'nflcation of the input signal being in

the range of normal operation, including evaluation of the signals rationality in comparison to all

available information.

OBD 11 Glossary - 4

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