This is a translation from the Funktionsrahmen

LAMBTS 2120 Lambda component protection FDEF 2120 LAMBTS function definition

ABK LAMBTS 2120 Abbreviations

FB LAMBTS 2120 Functional Description

Task

Protection of components (manifold, supercharger turbine, etc.) by mixture enrichment.

Principle

Excessive exhaust gas temperature (EGT) can be reduced by enriching the air-fuel mixture. This provides more highly enriched fuel into the cylinder than for a true stoichiometric mix. Combustion of the mixture is therefore incomplete due to insufficient oxygen. The unburned fuel condenses on the cylinder walls and transfers exhaust energy with it, thereby the exhaust gas temperature decreases.

LAMBTS: Description

Via the map KFLBTS can be dependent on the function of speed nmot and charge rl rich a lambda setpoint shift to make. The enrichment is only effective when the modeled temperatures tabgm_w, tkatm_w, tikatm_w or twistm_w in Partial function LAMBTSENABLE exceeds its applicable threshold and the switch delay time expired TDLAMBTS + TVLBTS is. Via the SYStem constant SY_ATMST can be defined whether the function exists twistm_w% ATMST and about the SY_ATMLA SYStem constant can be defined, whether twilam_w available from the function is ATMLA%. The map describes the stationary KFLBTS necessary enrichment, whereas the curves of the model temperatures, the dynamics describe.

This avoids that is enriched in short-term approach to a stationary critical operating point too early. The temperature hysteresis DTBTS DTWISBTS or prevent a periodic switching on and off of enrichment if, in the enrichment A temperature occurs which is below the cut-in. For projects with Stereo exhaust SYStem, where the exhaust temperatures of the two banks within the same operating point very strongly can differ, via the SYStem constant SY_STERBTS = true protection of the components over the maps KFLBTS, KFLBTS2 separated for both banks will be applied.

When deterioration of the ignition angle efficiency leads to an increase in the exhaust gas temperature. This increase can be with a mixture enrichment counteract (see Part DLAMBTSZW function). For this, the ignition angle efficiency etazwg the basic ignition angle and the ignition point ZWGRU average efficiency ignition angle when etazwim Actual ignition calculated firing angle. The difference of etazwg and etazwim results in the degradation efficiency detazwbs. Dependent on detazwbs can now via the map KFDLBTS an additive enrichment be carried out. The enrichment can be used in the desired range by means of the characteristic KFFDLBTS (nmot, rl) attenuated or eliminated. Again, this enrichment is only effective if one of the modeled exhaust temperatures below their corresponding threshold over. With the time delay TVLBTS, a short-term exceeding of the critical temperature components are allowed. Must first be However, the time TDLAMBTS have expired. With the low-pass filter ZDLBTS one has the possibility that otherwise abrupt enrichment to be ground upon reaching the critical component temperature.

Special thanks to phila_dot for translating this section.