Method for operating an internal combustion engine using exhaust gas purification system, and internal combustion engine

An internal combustion engine having an exhaust gas purification system, comprising:

• a first catalytic converter unit configured to generate ammonia with a rich exhaust gas composition from corresponding exhaust gas constituents;
• a second catalytic converter unit arranged downstream of the first catalytic converter unit and configured to temporarily store ammonia generated by the first catalytic converter unit with a rich exhaust gas composition and to subject nitrogen oxides present in exhaust gas to a reduction reaction using the temporarily stored ammonia as a reagent with a lean exhaust gas composition;
• and
• an injection system including:
• an arrangement configured to introduce a quantity of fuel in accordance with at least one preinjection, at least one main injection and at least one afterinjection;
• an arrangement configured to set an excess of oxygen in rich mode during combustion of the at least one preinjection and at least one main injection in a combustion chamber;
• and
• an arrangement configured to alter a time, a quantity and a duration of the at least one afterinjection to set one of the rich exhaust gas composition and the lean exhaust gas composition;
• wherein the at least one preinjection and the at least one main injection are burned under the excess oxygen to generate a quantity of nitrogen oxides sufficient for ammonia synthesis.

An internal combustion engine having an exhaust gas purification system, comprising:

• a first catalytic converter unit configured to generate ammonia with a rich exhaust gas composition from corresponding exhaust gas constituents;
• a second catalytic converter unit arranged downstream of the first catalytic converter unit and configured to temporarily store ammonia generated by the first catalytic converter unit with a rich exhaust gas composition and to subject nitrogen oxides present in exhaust gas to a reduction reaction using the temporarily stored ammonia as a reagent with a lean exhaust gas composition;
• and
• an injection system including:
• means for introducing a quantity of fuel in accordance with at least one preinjection, at least one main injection and at least one afterinjection;
• means for setting an excess of oxygen in rich mode during combustion of the at least one preinjection and at least one main injection in a combustion chamber;
• and
• means for altering a time, a quantity and a duration of the at least one afterinjection to set one of the rich exhaust gas composition and the lean exhaust gas composition;
• wherein the at least one preinjection and the at least one main injection are burned under the excess oxygen to generate a quantity of nitrogen oxides sufficient for ammonia synthesis.