Method and device for the continuous determination of damage to systems used for the post-treatment of heat engine exhaust gases

A lubricating oil, fuel and/or additive for oil or fuel is modified with a predetermined quantity of a radiotracer. The quantity of radiotracer accumulated in the post- treatment system (7) is measured using a detector (10) sensitive to radiation emitted by the retained radiotracer. The measurements are converted by a computer to give the degree of degradation of the post-treatment system. The radiotracer contains Zn, Ca, S, P and/or Mg, or a radioactive element with a short half-life, in particular Bromium-82 or Technetium 99-m. Technetium 99-m can be incorporated into the oil or fuel in the form of an aqueous solution of sodium pertechnetate NaTc04. The radiotracer is activated by neutron gun and/or by a proton beam before incorporation into the oil. The radiotracer replaces an additive in the oil Adh with an activatable additive EAdh with identical composition in identical quantity, or similarly a fuel additive Aci with an activatable additive EAci. An Independent claim is included for a device for continuously determining the degradation of at least one post-treatment system for exhaust gases, incorporating a detector sensitive to the radioactive tracer and a computer to convert the measurements into a degree of degradation. The post-treatment system is a oxidizing catalyst, a system for reducing or eliminating carbon oxides or a particle filter. The detector is an ionizing radiation detector. The device includes a filter (9) in the exhaust pipe between the post-treatment system and the point of ejecting the exhaust gases into the atmosphere.