On: Study: Some car models consuming around 50% more fuel than official results

[larrydag]

I'm guessing its across the industry. I'm wondering if this is the tip of the iceberg.

[emp_zealoth → larrydag]

Im pretty sure its just a case of completely out of control rules - they became impossible to follow, so everyone just decided to "play along"

[mpweiher → emp_zealoth]

Also rules that are in conflict. To get good mileage and corresponding low CO2 emissions, you need ultra lean mixtures. Alas, ultra lean mixtures produce more NOx.

You want low NOx emissions, you need richer mixtures, and thus higher fuel consumption and higher CO2 emissions.

[pbhjpbhj → mpweiher]

>ultra lean mixtures produce more NOx //

Isn't that where catalytic converters come in though?

Rules in conflict surely are required by the chemistry of the situation, the companies have to search for the local minima in order to comply.

[vonmoltke → pbhjpbhj]

> Isn't that where catalytic converters come in though?

Diesel exhaust is too oxygen-rich for the cat to effectively catalyze the NOx. That's why recent passenger car diesel systems have a Diesel Exhaust Fluid system.