Abstract: A hydrogen generator for use with an engine is disclosed. The hydrogen generator has an exhaust duct situated to receive exhaust from the engine, and an SCR device located within the exhaust duct. The hydrogen generator also has a housing in fluid communication with the exhaust duct upstream of the SCR device, an electrolyte solution disposed within the housing, and a plurality of electrodes at least partially submerged in the electrolyte solution. The electrodes are electrically powered to produce hydrogen gas, and the hydrogen gas is directed to mix with the exhaust.