Abstract: A method and apparatus are provided for reducing pollutants and especially nitrogen oxides, or NOx, in the exhaust gases of an engine. The apparatus includes a device for injecting ammonia into a conduit that extends between cylinder exhaust valves and a catalytic converter, to mix the ammonia with the exhaust gases. Ammonia injection occurs at a location a plurality of inches downstream of the exhaust valves to avoid burning of the ammonia by flames. The injection preferably occurs at a location where the exhaust gases are at a temperature of at least about 1200.degree. F. to cause considerable reaction of the ammonia with NOx in the exhaust gases prior to the gases reaching the catalyst, so less NOx must be removed along the catalyst.

Abstract: A method and apparatus are provided for reducing pollutants and especially nitrogen oxides, or NOx, in the exhaust gases of an engine. The apparatus includes a device for injecting ammonia into a conduit that extends between cylinder exhaust valves and a catalytic converter, to mix the ammonia with the exhaust gases. Ammonia injection occurs at a location a plurality of inches downstream of the exhaust valves to avoid burning of the ammonia by flames. The injection preferably occurs at a location where the exhaust gases are at a temperature of at least about 1200.degree.F. to cause considerable reaction of the ammonia with NOx in the exhaust gases prior to the gases reaching the catalyst, so less NOx must be removed along the catalyst. To minimize ammonia use, it is injected only for a limited period such as a minute after a cold engine is started when the catalyst is too cold to cause significant reactions, and during operation of the engine at high power levels when the greatest amounts of NOx are produced.

Abstract: A germicidal toothbrush holder includes a substantially closed, upright cylindrical housing having a detachable top lid. The lid has an annular array of openings through which the bristled ends of toothbrushes may be inserted and removed. A UV lamp of low intensity is operably mounted within the housing for emitting ultraviolet radiation in the 200 to 300 nanometer wavelength range, as well as some radiation in the visible range above 300 nanometers and in the ozone producing range below 200 nanometers. A removable cup structure supports the bristled ends of the toothbrushes in an annular array immediately surrounding the lamp, and has an annular interior surface coated with aluminum for high reflectance of UV radiation. The UV lamp is on continuously to expose the toothbrushes to germicidal radiation and to generate small quantities of ozone which accumulate to have some sterilizing effect.