Method and system for use when correcting supply of an additive to an exhaust gas stream

A computer program product comprising computer program code stored on a non-transitory computer-readable medium, said computer program product for determining when to correct supply of additive to an exhaust gas stream resulting from combustion in at least one combustion chamber, wherein the additive is arranged for reduction of at least one substance resulting from said combustion by supplying the additive to an exhaust gas stream resulting from said combustion, wherein the quantity of additive being supplied is subjectable to correction, and wherein a sensor is subjected to the exhaust gas stream and arranged to measure occurrence of said at least one substance, said computer program product comprising computer instructions to cause one or more computer processors to perform the following operations:

• by means of sensor signals from said sensor, determining a level of emission of said first substance in said exhaust gas stream;
• and
• determining a length of at least one interval between corrections to said supply of additive to the exhaust gas stream, where the length of the at least one interval is based on said level of emission of said first substance in said exhaust gas stream.

A system for determining when to correct supply of additive to an exhaust gas stream resulting from combustion in at least one combustion chamber, wherein the additive is arranged for reduction of at least one substance resulting from said combustion by supplying the additive to an exhaust gas stream resulting from said combustion, wherein the quantity of additive being supplied is subjectable to correction, and wherein a sensor is subjected to the exhaust gas stream and arranged to measure occurrence of said at least one substance, the system comprising:

• means for, by means of sensor signals from said sensor, determining a level of occurrence of said first substance in said exhaust gas stream;
• and
• means for determining a length of at least one interval between corrections to said supply of additive to the exhaust gas stream, where the length of the at least one interval is based on said level of emission of said first substance in said exhaust gas stream.

A vehicle comprising a system for determining when to correct supply of additive to an exhaust gas stream resulting from combustion in at least one combustion chamber, wherein the additive is arranged for reduction of at least one substance resulting from said combustion by supplying the additive to an exhaust gas stream resulting from said combustion, wherein the quantity of additive being supplied is subjectable to correction, and wherein a sensor is subjected to the exhaust gas stream and arranged to measure occurrence of said at least one substance, the system comprising:

• means for, by means of sensor signals from said sensor, determining a level of occurrence of said first substance in said exhaust gas stream;
• and
• means for determining a length of at least one interval between corrections to said supply of additive to the exhaust gas stream, where the length of the at least one interval is based on said level of emission of said first substance in said exhaust gas stream.