EXHAUST GAS TREATMENT FOR A TWO STROKE ENGINE

摘要

A two-stroke spark ignited engine (10) with direct fuel injection (14) and an exhaust gas treatment catalyst. A separate catalyst unit (23) is provided for each combustion chamber (11) and is located at or adjacent each exhaust port (15) from that chamber and that during a cycle of each combustion chamber (11) the catalyst unit (23) of that combustion chamber (11) is exposed only to exhaust gases which change from chemically reducing to chemically oxidising during the cycle. An engine which has exhaust gases which are overall chemically oxidising can thus nevertheless have the NOx constituents of the gases reduced.