Exhaust gas after-treatment device and propulsion system including the device

A propulsion system comprising a diesel engine and an exhaust gas after-treatment device operatively associated with an exhaust manifold of the diesel engine, the after-treatment device comprising in succession a barium-loaded three-way catalyst, an anti-particulate filter and a selective reducing catalyst equipped with the relative doser of urea-based reducing agent, wherein the barium-loaded three-way catalyst is arranged upstream of the exhaust gas filter-after treatment device and the antiparticle filter and the selective reducing catalyst-equipped with the relative doser of urea-based reducing agent are arranged downstream of the exhaust gas filter after-treatment device.

A method for controlling a fuel supply of a propulsion system comprising a diesel engine and an exhaust gas after-treatment device operatively associated with an exhaust manifold of the diesel engine, the post-treatment comprising in succession a catalyst and three-way loaded with barium, an anti-particulate filter and a selective reducing catalyst equipped with a relative dispenser of reducing agent based on urea, the method comprising:

• (i) stoichiometric fuel supplying the engine in cold starting conditions, while a first temperature threshold is reached, measured by means of a first temperature sensor,
• (ii) generally lean engine fuel supplying with cyclic enrichments of the mixture so as to induce regenerations of the barium-loaded three-way catalyst while reaching a second temperature threshold measured by means of a second temperature sensor, and
• (iii) stably lean feeding the engine and activation of the urea-based reducing agent doser, wherein the barium-loaded three-way catalyst is arranged upstream of the exhaust gas filter-after treatment device and the antiparticle filter and the selective reducing catalyst-equipped with the relative doser of urea-based reducing agent are arranged downstream of the exhaust gas filter after-treatment device.