If hydrogen is available from the exhaust, the TWC/TWNSC will also create ammonia, which reduces the necessary degree of urea injection; The hydrogen respiratory apparatus arrived a couple of days ago. I breathe hydrogen on a daily basis. My coughing stopped. Such as the lithium-ion cells within an EV battery, https://hydrogencar27035.blog-a-story.com/5860363/reduce-fuel-for-dummies