Catalytic heater for an exhaust gas system of an internal combustion engine, exhaust gas system and method of operating an exhaust gas system

A method of operating an exhaust gas system including:

• at least one exhaust gas treatment assembly;
• a catalytic heater arranged downstream of said at least one exhaust gas treatment assembly with regard to an exhaust gas flow direction;
• said catalytic heater including:
• at least one electrically excitable heating element;
• a hydrocarbon release arrangement for releasing liquid hydrocarbon toward said at least one electrically excitable heating element;
• and, an oxidation catalyst arrangement for oxidizing the hydrocarbon heated at said at least one electrically excitable heating element;
• the method comprising the step of:
• operating the at least one electrically excitable heating element of the catalytic heater such that liquid hydrocarbon meets a surface of the at least one electrically excitable heating element and is heated and is oxidized over the oxidation catalyst arrangement to generate heat,
• wherein the excitation of the at least one electrically excitable heating element is started before startup of an internal combustion engine,
• wherein the injection of hydrocarbon onto the at least one electrically excitable heating element is commenced before startup of the internal combustion engine, wherein:
• a) before startup of the internal combustion engine, in a preinjection operation, hydrocarbon is injected in at least one of the following ways:
• i) in a predetermined amount;
• and, ii) for a predetermined period of time;
• b) after the preinjection operation has ended, the internal combustion engine is driven to rotate without ignition;
• and,
• c) before startup of the internal combustion engine, in a last preinjection operation, hydrocarbon is injected in at least one of a following ways:
• i) in a predetermined amount;
• and, ii) for a predetermined period of time.

A method of operating an exhaust gas system including:

• at least one exhaust gas treatment assembly;
• a catalytic heater arranged downstream of said at least one exhaust gas treatment assembly with regard to an exhaust gas flow direction;
• said catalytic heater including:
• at least one electrically excitable heating element;
• a hydrocarbon release arrangement for releasing liquid hydrocarbon toward said at least one electrically excitable heating element;
• and, an oxidation catalyst arrangement for oxidizing the hydrocarbon heated at said at least one electrically excitable heating element;
• the method comprising the step of:
• operating the at least one electrically excitable heating element of the catalytic heater such that liquid hydrocarbon meets a surface of the at least one electrically excitable heating element and is heated and is oxidized over the oxidation catalyst arrangement to generate heat,
• wherein, after the internal combustion engine has been started up, the hydrocarbon injection rate is determined depending on at least one of the following:
• i) a temperature of the oxidation catalyst arrangement;
• and, ii) an exhaust gas volume flow rate in the exhaust gas system,
• wherein at least one of the following applies:
• i) the hydrocarbon injection rate increases with increasing temperature of the oxidation catalyst arrangement;
• and,
• ii) the hydrocarbon injection rate decreases with increasing exhaust gas volume flow rate.