A cost-effective solution to remove particulates from diesel, especially light-duty diesel engines incorporates an oxidation catalyst effective to convert NO in the exhaust from the engine to NO2 and a particulate trap which traps no more than 85% by weight of the particulate, optionally by permitting gas to by-pass the trap. The electrical resistance of the field coil is measured and the temperature of the field coil, constituting a first temperature, is calculated based on the measured resistance of the field coil. The stabilizing structure stabilizes a separated gas recirculation zone.