The main purpose of this work was to demonstrate that steam reforming of methylal (dimethoxymethane, MA), even at low steam-to-MA ratios, can be used for thermal recuperation of the energy of internal combustion engine exhaust gas. This work confirms that high conversion to H2 and CO can be achieved at temperatures above 450 °C on alumina-supported Pt (0.1%) or Cu catalysts, with S/MA = 1. These temperatures can be achieved by heating with exhaust gases and simulations showed that reaction can be completed in a reformer-heat exchanger of a reasonable size. This work differs from previous MA SR studies that employed either S/MA = 5 aimed at maximizing H2 production for fuel cells or S/MA = 0, which was shown to be insufficient for reasonable recuperation. Several conclusions can be reached from the performance dependence on S/MA ratio. Pt catalyst gives nearly complete MA conversion above 300 °C with S/MA = 1 or 4. The major products were H2, CO, and methanol. Methanol is produced in large amounts with decreased production of dimethyl ether (DME) compared to results with methylal decomposition (S/MA = 0), which showed large DME production. This is consistent with the methanol-DME equilibrium in the presence of water. On a mechanically mixed catalyst of Cu-Al2O3 with alumina, the results with S/MA = 1 show that the catalyst is somewhat less active than the Pt one (requiring more catalyst), but high production of H2 and CO can be achieved above 450 °C. The experimental results in the temperature range of 200-350 °C were used to construct a mathematical model of four reactions (MA decomposition, DME hydrolysis, methanol decomposition, and water-gas shift reaction). The model was used for extrapolation to higher temperatures and led to the conclusion above.