Compensating for the TDI's summer weakness with increased turbo boost?

Hi everyone,

Now that it's getting warmer, we occasionally see 2000-4000 readings classified as "bad" because colder intake air brings more mass into the cylinders and allows for a higher fuel injection volume.
So it seems that in the summer, the amount of fuel injected is not limited by the torque map, but rather by the reading from the mass airflow sensor.

Conversely, it should be possible to achieve the higher winter performance in summer by increasing the boost pressure, which results in better cylinder filling, as long as the mass airflow sensor reports the same air mass flow rate as in winter.

Regardless of the required additional load on the charger: What do you think about it? Are there any other effects or parameters that I haven't considered?

Hello Ulf,

If we are only concerned with the LMM values, it is possible to adjust them via adaptation channels.
To perform an adjustment, it's possible to make the engine control unit believe that a larger amount of air is being drawn in than actually is (this only helps with the smoke map, not the torque map). Furthermore, the EGR map must be taken into account (as you correctly pointed out).

Hi everyone.


Spielen noch andere Effekte oder Kennfelder eine Rolle, die ich nicht bedacht habe?


Hello.

A tuner once told me that there's a map that reduces the fuel injection amount depending on the temperature of the intake air behind the intercooler. Maybe it would help to influence the value of the sensor using a voltage divider.

Michael II wrote:

If it's only about the LMM values, an adjustment can be made via the adaptation channels. This makes it possible to make the control unit believe that a larger amount of air is being drawn in than is actually the case (this only helps with the smoke map, not with the torque map). Weiterhin muß das AGR Kennfeld berücksichtigt werden (wie Du auch schon richtig gepostet hast).

Hi Michael,

If you trick the engine computer into thinking that more air is entering than actually is, the EGR function will naturally become disrupted.

What I was trying to do was actually get more air into the cylinders - by increasing the boost pressure.
"Then, in my opinion, the torque curve should eventually become the limiting factor for fuel injection rather than soot emissions, and it should be possible, for example, to achieve draft times (and top speeds) similar to those at -10°C during the summer."

Or does the intake air temperature actually still have a direct limiting effect on the fuel injection quantity?