Additive delivery system and method for controlling said system

1. An additive delivery system comprising:

a tank for storing an additive;

an active component; and

a controller connected to the active component,

wherein the controller is adapted to determine a temperature of the additive in the system based on an electrical characteristic of a part inside the active component or inside said controller,

wherein said part has a further function in addition to a temperature estimation function in normal operation of the additive delivery system, and

wherein the active component comprises a pump for pumping additive, said pump having an electrical motor with a coil wire, wherein said part is formed by the coil wire.

2. The additive delivery system of claim 1 ,

wherein said part is an electrical wire, and

wherein the controller is adapted to apply a determined voltage across said wire and to measure a current through said wire, said measured current being a value representative for the temperature of the additive; or adapted to send a determined current through said wire and to measure a voltage across said wire, said measured voltage being the value representative for the temperature of the additive.

3. The additive delivery system of claim 2 ,

wherein said controller comprises a DC voltage source for applying the voltage across said wire and a current measuring device for measuring the current through said wire; or

wherein said controller comprises a DC current source for sending a current through said wire and a voltage measuring device for measuring the voltage across said wire.

4. The additive delivery system of claim 1 , wherein said additive delivery system is an SCR system.

5. A method for controlling an additive delivery system comprising:

determining by means of a controller, a temperature of an additive in the additive delivery system based on at least one electrical characteristic of at least one part inside at least one of an active component and the controller of the additive delivery system;

performing other controlling operations involving said part,

wherein the active component comprises a pump for pumping additive, said pump having an electrical motor with a coil wire, wherein said part is formed by the coil wire.

6. The method of claim 5 , wherein said at least one electrical characteristic is a value representative of a resistance of the part and is measured inside the controller.

7. The method of claim 5 , wherein one or more electrical characteristics are received from the active component, and wherein said one or more electrical characteristics are used for other controlling functions different from the determining by the controller of a value representative for the temperature of the additive in the system.