Exhaust gas system with preconditioning

A method for operating an exhaust gas system for discharging and purifying combustion exhaust gases of an internal combustion engine, comprising:

• operating the exhaust gas system in a preconditioning mode by performing preconditioning steps with the internal combustion engine switched off, the preconditioning steps including,
• heating air by a heating element in the exhaust gas system,
• operating an electrically assisted exhaust gas turbocharger in the exhaust gas system to produce a hot air stream with the heated air,
• circulating the hot air stream to heat a first catalytic converter of the exhaust gas system to at least a minimum operating temperature by conducting the hot air stream in a circuit through the first catalytic converter via a bypass line having a bypass valve that is opened at least partially to conduct the hot air stream through the bypass line, the bypass valve being utilized as an external wastegate of the exhaust gas turbocharger;
• operating the exhaust gas system in a normal operation mode by performing normal operation steps after the preconditioning steps, the normal operation steps including switching off the heating element and the exhaust gas turbocharger and starting the internal combustion engine;
• and
• conducting combustion exhaust gases out of the internal combustion engine through the bypass line bypassing both the exhaust gas turbocharger and the first catalytic converter in the case of an open bypass valve, and a boost pressure produced by the exhaust gas turbocharger being regulated via a degree of opening the bypass valve.

An exhaust gas system for discharging and purifying combustion exhaust gases of an internal combustion engine, the exhaust gas system comprising:

• an exhaust gas manifold for receiving the combustion exhaust gases from the internal combustion engine;
• a fan;
• a first catalytic converter having a catalytic converter outlet;
• a heating element for heating air;
• a first line section;
• a second line section;
• a third line section;
• a bypass line;
• and
• a bypass valve arranged on the bypass line and operative for selectively opening and closing the bypass line by a specified amount, the bypass valve being a wastegate;
• wherein the exhaust gas manifold is connected to the first line section;
• the second line section, the fan, the first catalytic converter and the catalytic converter outlet are connected to form a first exhaust gas path between the first line section and the third line section;
• the bypass line is a second exhaust gas path between the first line section and the third line section;
• and
• the first exhaust gas path and the second exhaust gas path form a circuit.