Performance issues - predictable?

Hi,

Can the performance loss due to insufficient air mass, and consequently reduced fuel injection, be roughly estimated or calculated based on the engine type?

Let's take an AFB engine as an example.
The MSG specifies a target air mass of approximately 880 mg/h. If, for example, the engine only reports 800 mg/hour from the mass airflow sensor (MAF) due to a malfunctioning EGR system, wouldn't the fuel injection amount also decrease?

Can we infer from this how much percentage of performance is missing?

With 10% less air mass = 10% less power, which is already 150 standard horsepower, meaning 15 'lost' horsepower – can you really calculate with that?

Regarding your example, the AKN is similar to the AFB. The soot limit doesn't immediately engage when the target values are not reached. Therefore, it's important to know at what air mass the performance is reduced. According to Ulf, the LMM (mass airflow sensor) only indicates the soot limit up to a maximum value. So, even with an air mass of 1000, the soot limit might not be higher. Therefore, the difference between (my) torque limitation and soot limitation doesn't always indicate the minimum air mass required before power loss occurs.

It would be possible to calculate how much diesel fuel corresponds to a certain amount of air per injection, and how much power that amount of diesel fuel would produce. I don't know if having 10% less air mass than the optimal amount would also result in 10% less power, while still staying below the soot limit. I'm sure someone can definitely calculate that for you.

A good example of what's described above is in the link listed below . It shows that even if the desired air mass is not reached, the fuel injection amount does not necessarily have to be reduced.

Okay, I'm ready. Please provide the German text you want me to translate.

vagtuning wrote:

Hi, Can the performance loss due to insufficient air mass, and consequently reduced fuel injection, be roughly estimated or calculated based on the engine type? Let's take an AFB engine as an example. The MSG specifies a target air mass of approximately 880 mg/h. If, for example, the engine only reports 800 mg/hour from the mass airflow sensor (MAF) due to a malfunctioning EGR system, wouldn't the fuel injection amount also decrease? Can we infer from this how much percentage of performance is missing? With 10% less air mass = 10% less power, which is already 150 standard horsepower, so 15 "missing" horsepower, can you really calculate with that?

Without knowledge of the specific data available (turbidity-KF), such a forecast is hardly possible.

Supplement to Tom's answer:

One might, for example, come up with the idea that a mass ratio of diesel to air below 1.1 (mass ratio of diesel to air = 1:16) could shut down the process.
Then, one could log the engine's rotational speed throughout its entire usable range, multiply all injection volumes by 16, and thereby obtain the minimum air mass required for the full injection volume.

Unfortunately, the turbidity value is very variable.
In the low-speed range, the value sometimes goes down to nearly 1.0, but at full load, it varies depending on the power level and vehicle model, ranging from approximately 1.15 to 1.40. . .