Thread by @AukeHoekstra

This is a myth that you still hear now and then: modern diesels actually *clean* the air. Now again the biggest newspaper of the Netherlands.

What they don't tell you is that this is only true for large trucks on dirty highways and that diesels don't help against climate change.

https://twitter.com/telegraaf/status/1209191555879329793

Why only large trucks on dirty roads? Well, for normal cars the amount of cheating is so eye watering that diesels are extremely dirty #dieselgate

sciencedirect.com/science/articl…

This is still true: e.g. katalysers are regularly burnt off to clean them. Not during testing of course.

If you use ad-blue you might have one of the few "not too bad" diesels, but even with ad-blue chances are your exhaust is very dirty.

For large trucks the testing is somewhat better and here originates the claim that on a dirty road they can reduce NOx. BUT it's irrelevant.

First it's irrelevant because these engines reduce some stuff that's measured, only to increase other unhealthy stuff that's not. Ask @mzjacobson if you are really interested.

We will be rid of diesel long before the industry becomes honest and the engines clean.

Second it's irrelevant because of this thing called global warming. CO2 emissions of diesel cars are not that much lower than gasoline in the real world and close to their economic and theoretical maximum.

Yes, you can shave off ~30% more, theoretically, but that's about it.

EVs already shave off ~50% for trucks and ~70% of cars.

Once production and driving are done on low carbon electricity you can come close to eliminating CO2 emissions all together.

Mathematically speaking that's infinitely better.

So I can understand the frustration of engineers in academia and in industry who devoted their life to improving diesel who find they are increasingly irrelevant. But don't be confused: it's on the way out and for good reasons.