Abstract: An operational control system for an internal combustion engine, an internal combustion engine, a vehicle and a method of onboard generation of hydrogen in a vehicle being powered by an internal combustion engine. The operational control system includes a source of electric current, a gas generator with a supply of hydrogen precursor material and one or both of an SCR device and a fuel octane boosting device. The gas generator is configured to convert the contained precursor material into an H2 gas by operation of solar energy, electrical energy or both being delivered by the source. The SCR device is fluidly cooperative with the gas generator such that a catalyst-activated fluid-permeable medium disposed in an exhaust gas flowpath defined by the SCR device accepts the passage of the exhaust gas through it and at least intermittently receives the H2 gas from the gas generator to perform catalytic reduction of NOx.