Exhaust-gas heater

An exhaust-gas heating system for an exhaust system for an internal combustion engine, the exhaust-gas heating system comprising:

• at least one exhaust-gas heater for accommodating a flow of exhaust gas (A) therethrough;
• said exhaust-gas heater including:
• a heating conductor having a first supply-voltage terminal and a second supply-voltage terminal;
• said heating conductor defining a heating region extending between said first and said second supply-voltage terminals;
• a voltage-measuring section exhibiting a resistance characteristic different from a resistance characteristic of said heating region and being integrated into said heating region;
• said voltage-measuring section including:
• a measuring resistor;
• said heating region defining first and second heating-region portions;
• said measuring resistor having first and second terminal regions connected to said first and second heating-region portions, respectively, leading to corresponding . . . ones of said first and second supply-voltage terminals;
• said measuring resistor being electrically connected in series with said first heating-region portion and with said second heating-region portion;
• said measuring resistor further including a first voltage-measuring terminal formed thereon in a region of said first terminal region and a second voltage-measuring terminal formed thereon in a region of said second terminal region;
• said exhaust-gas heating system further including:
• a control arrangement for registering a measuring voltage between said first and second voltage-measuring terminals and for applying a supply voltage between said first and second supply-voltage terminals as a function of the registered measuring voltage;
• wherein at least one of the following applies:
• said voltage-measuring section exhibits an electrical resistance changing with greater intensity in a temperature-dependent manner than said heating region within an operating temperature range;
• and,
• said voltage-measuring section exhibits a lower electrical resistance than said heating region within said operating temperature range.

An exhaust system for an internal combustion engine, the exhaust system comprising:

• an exhaust-gas heating system including:
• at least one exhaust-gas heater for accommodating a flow of exhaust gas (A) therethrough;
• said exhaust-gas heater including:
• a heating conductor having a first supply-voltage terminal and a second supply-voltage terminal;
• said heating conductor defining a heating region extending between said first and said second supply-voltage terminals;
• a voltage-measuring section exhibiting a resistance characteristic different from a resistance characteristic of said heating region and being integrated into said heating region;
• said voltage-measuring section including:
• a measuring resistor;
• said heating region defining first and second heating-region portions;
• said measuring resistor having first and second terminal regions connected to said first and second heating-region portions, respectively, leading to corresponding ones of said first and second supply-voltage terminals;
• said measuring resistor being electrically connected in series with said first heating-region portion and with said second heating-region portion;
• said measuring resistor further including a first voltage-measuring terminal formed thereon in a region of said first terminal region and a second voltage-measuring terminal formed thereon in a region of said second terminal region;
• said exhaust-gas heating system further including:
• a control arrangement for registering a measuring voltage between said first and second voltage-measuring terminals and for applying a supply voltage between said first and second supply-voltage terminals as a function of the registered measuring voltage;
• wherein at least one of the following applies:
• said voltage-measuring section exhibits an electrical resistance changing with greater intensity in a temperature-dependent manner than said heating region within an operating temperature range;
• and,
• said voltage-measuring section exhibits a lower electrical resistance than said heating region within said operating temperature range.

A method for operating an exhaust-gas heater including:

• a heating conductor having a first supply-voltage terminal and a second supply-voltage terminal;
• said heating conductor defining a heating region extending between said first and said second supply-voltage terminals;
• a voltage-measuring section exhibiting a resistance characteristic different from a resistance characteristic of said heating region and being integrated into said heating region;
• said voltage-measuring section including:
• a measuring resistor, said heating region defining first and second heating-region portions, said measuring resistor having first and second terminal regions connected to said first and second heating-region portions, respectively, leading to corresponding ones of said first and second supply-voltage terminals, said measuring resistor being electrically connected in series with said first heating-region portion and with said second heating-region portion, and, said measuring resistor further including a first voltage-measuring terminal formed thereon in a region of said first terminal region and a second voltage-measuring terminal formed thereon in a region of said second terminal region;
• wherein at least one of the following applies:
• said voltage-measuring section exhibits an electrical resistance changing with greater intensity in a temperature-dependent manner than said heating region within an operating temperature range;
• and,
• said voltage-measuring section exhibits a lower electrical resistance than said heating region within said operating temperature range;
• the method comprising:
• a) applying a supply voltage between the first supply-voltage terminal and the second supply-voltage terminal;
• b) registering a measuring voltage between said first voltage-measuring terminal of said voltage-measuring section and said second voltage-measuring terminal of said voltage-measuring section;
• and,
• c) carrying out one of the following steps:
• c1) comparing the measuring voltage registered in the course of step b) with a set measuring voltage to ascertain a voltage deviation between the registered measuring voltage and the set measuring voltage, and setting the supply voltage as a function of the voltage deviation in such a manner that the registered measuring voltage lies within the range of the set measuring voltage,
• or
• c2) comparing a temperature ascertained on the basis of the measuring voltage registered in the course of step b) with a set temperature for the purpose of ascertaining a temperature deviation between the ascertained temperature and the set temperature, and setting the supply voltage as a function of the temperature deviation in such a manner that the ascertained temperature lies within the range of the set temperature.