Abstract: An internal combustion engine vehicle or hybrid-electric vehicle is provided with a vehicle-mounted solar cell array capable of generating electrical power. The solar cell array and other elements, including a metal substrate catalytic convertor form a system for reducing exhaust gas emissions from the vehicle in which the power from the array is applied to minimize exhaust emissions. A primary application of the solar cell array-generated power is to preheat the catalytic convertor to a preferred operating temperature prior to engine start. But the power from the solar cells, directed by a controller, may also be applied to charge the battery or to power electric power receiving devices, for example, to control cabin temperatures. The preferred allocation of the solar power available depends on a number of factors including the state of charge of the batteries, and the time of anticipated next use of the vehicle.