PSA Citroën patent number FR2880657 entitled "Exhaust gas recirculation circuit" (with reformer and hydrogen injection to promote combustion)
(…) It has been shown that adding hydrogen-rich gas (H2) to the combustion chamber intake manifold, during recirculation of the exhaust gases, makes it possible to reduce hydrocarbon emissions unburnt (HC), carbon monoxide (CO) and soot.
The power output of the engine is thus improved while limiting the emissions of carbon products.
In known manner, fuel reforming is obtained by reacting fuel molecules with water and / or air to produce hydrogen according to the following chemical reactions…
The following in the document.
Read more and debate: injecting hydrogen into the fuel