Test results in 2004 show “that the H2 rich reformate gas was an excellent NOx reductant, and can out perform raw Diesel fuel as a reductant in a wide range of operating conditions”. This is referring to Diesel fuel being used in excess, as a reductant, to cool the combustion reaction, which indeed has a mitigating effect on NOx production.
In 2004 research was conducted concluding that an “SI engine system fueled by gasoline and hydrogen rich reformate gas has been demonstrated” to achieve a “dramatic reduction of pollution emissions”. This was achieved by “extending EGR operation” in addition to consuming “gasoline and hydrogen rich reformate”. Emissions results show that “HC-emissions as well as NOx-emissions could be reduced to near zero”. Overall a 3.5% reduction in CO2 emissions was achieved during the “FTP test cycle” The research also concluded that the exhaust after treatment system can be simplified, “resulting in cost reduction for the catalysts”.