Euro 6: Disable EGR? Is EGR Removal Possible?

Hello everyone,
With an increasing number of truck manufacturers achieving the Euro 6 standard without using exhaust gas recirculation, I wonder why this approach isn't also being applied to passenger cars.
According to some truck manufacturers, the absence of an EGR system can save up to 10% in fuel consumption. However, AdBlue consumption increases from 3% to 6%. Active DPF regeneration via post-injection is no longer necessary, and the DPF has a significantly longer lifespan.

Couldn't one simply deactivate the EGR (Exhaust Gas Recirculation) system in a Euro 6 passenger car with an SCR (Selective Catalytic Reduction) system? Wouldn't the increased NOx emissions theoretically be offset by increasing the AdBlue injection to bring the value back to the permissible level?

I once created a calculation, using figures that were probably not entirely realistic.

10 liters of diesel per 100 km, minus a 5% reduction (I think 10% is a bit too optimistic), results in a savings of 0.5 liters, which is equivalent to €0.65.
Using 0.6 liters of AdBlue instead of 0.3 liters would incur an additional cost of €0.20 (given a pump price of €0.65 per liter).
This results in a total savings of €0.45 per 100 km.
If we consider the cost of the DPF to be €1500 with a lifespan of 250,000 km, and if the absence of an EGR system doubles the DPF's lifespan, the cost per 100 km would decrease from €0.6 to €0.3.

If everything were to work as intended, it would save 0.75€ per 100 km.


I'm not trying to manipulate any exhaust systems or anything like that.
I would just like to hear your opinions on this topic.

To operate without an EGR system, the combustion process is tuned for low fuel consumption and high NOx emissions (I'm leaving aside any external factors that might affect particle mass and size). Then, a large SCR catalyst is added to the rear, and that's how the "high-NOx system" of modern trucks is created.

Because an SCR catalyst ages over time, and to ensure that there is still sufficient reactive surface area in the substrate at the end of its intended lifespan to minimize ammonia slip, an SCR catalyst used for NOx reduction without exhaust gas recirculation (EGR) for internal engine NOx reduction would need to be larger and more expensive than is feasible for most cars.

It is also becoming increasingly difficult to bring a catalytic converter of this size to the temperature required for its function using only resources available in the vehicle, especially under low load conditions.

Regards,

Okay, please provide the German text you would like me to translate.

Apart from the fact that it leads to the revocation of the operating license, which makes it counterproductive...

Truck engines have a different performance profile compared to passenger car engines. What percentage of the time do you run your car at full load...? Probably not much, maybe 1-2% unless you're constantly flooring it. This is completely different for trucks; it's like comparing apples and oranges.

The discussion would not be productive. The previous speaker mentioned some reasons, and there are certainly more.

When you examine the fuel injection start maps of commercial vehicle engines, you'll notice that the fuel injection timing is particularly late in load ranges where the exhaust gas temperature is not reliably high enough for SCR (Selective Catalytic Reduction) to function effectively. Many passenger car engines operate precisely in this low-load range.
For one reason, and also because an AGR (Abgasrückführung) is a "heat recovery system," car engines often use AGR systems.

I saw something like that with heat recovery on a Euro5 engine. With an outside temperature of -8°C, the engine was running at high RPM, the heating was on, and the EGR was deactivated, and it couldn't reach operating temperature.