Apparatus for the detoxification of exhaust gases

In an apparatus for the detoxification of exhaust gases of an internal combustion engine having (a) a suction tube for air intake to the engine, (b) an air quantity measuring device disposed in said suction tube, (c) fuel metering means for metering out fuel corresponding to the air quantity measured by said air quantity measuring device so as to achieve slightly enriched fuel-air mixture, (d) an exhaust system for the exhaust gases of the engine, and (e) an oxygen sensing means disposed in said exhaust system, the improvement comprising:

• (f) a secondary pump, (g) means including a secondary air line connected between said secondary air pump and an inlet to said suction tube downstream of said air quantity measuring device, and (h) means connected to and controlled by said oxygen sensing means and connected to said means including said secondary air line for controlling the admission of secondary air from the secondary air pump to the suction tube through said secondary air line, until such time as an optimum value of air number is reached, wherein said means for controlling the admission of secondary air includes:
• i. a magnetic valve means disposed within said secondary air line;
• and
• ii. a control device electrically disposed between said magnetic valve means and said oxygen sensing means for amplifying the output voltage of said oxygen sensing means and cyclically controlling said magnetic valve means proportionally to said amplified output voltage, wherein the opening point of said magnetic valve means is cyclically controlled by said control device at a frequency proportional to the engine rpm, in dependence on a signal fed to said control device by an engine rpm measuring means, and wherein the duration of opening of said magnetic valve means is controlled by said control device in dependence on the output voltage of said oxygen sensing means.