Method and apparatus for electrically heating a catalytic converter

An apparatus for heating a catalytic converter arranged in an exhaust-gas tract of an internal combustion engine, the apparatus comprising:

• an electric heating device;
• and
• a temperature sensor arranged in a region of the catalytic converter adjacent to the heating device;
• an air conveying device supplying a secondary air mass flow into the exhaust-gas tract at a point upstream of the catalytic converter;
• and
• an electronic control unit programmed to:
• activate the electric heating device with a specified heating power at a time before the internal combustion engine is started;
• monitor the catalyst temperature in a region of the catalytic converter adjacent the heating device;
• before the catalyst temperature has reached a predetermined first threshold value, suppler a secondary air mass flow with a first flow rate is supplied into the exhaust-gas tract upstream of the catalytic converter;
• and
• after the catalyst temperature has reached the predetermined first threshold value, increase the secondary air mass flow to a second flow rate greater than the first flow rate.