TDI Exhaust: How Does the 1Z Model Work?

Hi.

I just logged in a little bit.

"For me, the mass airflow sensor (MAF) value starts to drop significantly above 3000 RPM, and above 4000 RPM, the Russian border kicks in (meaning that in block 8, the value of 4 is the lowest)."

Is this a consequence of a too-low LMM value, or is the engine being regulated back due to exceeding the exhaust gas recirculation (EGR) limit? In other words, does the EDC (Engine Control Unit) start to become "cautious" already at 4000 RPM?

http://www.luxus-wg.de/~martin/auto_bilder/LMM_defekt2.jpg

Thank you.
m;

Well, if the engine isn't getting enough air, the soot reduction system will activate sooner or more frequently, which makes sense...

In my ALH engine, the fuel injection amount was simply reduced depending on the engine speed, while the soot limit remained 'unchanged.'

dieselmartin wrote:

Is this now a consequence of a too-low LMM value, or is the engine being regulated back due to exceeding the soot limit - so does the EDC start to "become cautious" already at 4000 RPM?

"In my opinion, no developer would actually implement this, as it would be too simplistic to base the derating solely on the 'unreliable' mass airflow sensor reading. Factors like mass airflow sensor aging, temperature, and actual boost pressure would shift the derating range to varying degrees."

In the torque curve, a noticeable drop-off is also evident: above approximately 4000 rpm, the torque decreases much more sharply than it does up to 4000 rpm.
As long as LMM and similar systems are functioning correctly, this regulation applies.