Method, computing unit, and computer program for determining an amount of hydrocarbons in an exhaust gas of a lean-operation internal-combustion engine

A computing unit (140) configured to:

• execute a first catalyst heating mode of the internal-combustion engine (110) at a first catalyst temperature, wherein a predefinable amount of fuel having a predominantly non-combusting portion is introduced into a combustion chamber of the internal-combustion engine (110),
• receive, from an exhaust temperature sensor (125), an actual temperature change downstream of an oxidation catalyst (120) downstream of the internal-combustion engine (110) during the first catalyst heating mode,
• determine the amount of hydrocarbons (cHC) in the exhaust gas (10) upstream of the oxidation catalyst (120) based on the actual temperature change,
• calculate an expected temperature change (TExo_Mdl) downstream of the oxidation catalyst (120), taking into account the predefinable amount of fuel, and
• correct (rHC_Adapt) the calculation of the expected temperature change based on a difference (TExo_Dvt) between the actual temperature change and the expected temperature change (TExo_Mdl).

A non-transitory computer-readable medium including instructions executable by an electronic processor to perform a set of functions, the set of functions comprising:

• executing a first catalyst heating mode of an internal-combustion engine (110) at a first catalyst temperature, wherein a predefinable amount of fuel having a predominantly non-combusting portion is introduced into a combustion chamber of the internal-combustion engine (110),
• receiving, from an exhaust temperature sensor (125), an actual temperature change downstream of an oxidation catalyst (120) downstream of the internal-combustion engine (110) during the first catalyst heating mode,
• determining the amount of hydrocarbons (cHC) in the exhaust gas (10) upstream of the oxidation catalyst (120) based on the actual temperature change,
• calculating an expected temperature change (TExo_Mdl) downstream of the oxidation catalyst (120), taking into account the predefinable amount of fuel, and
• correcting (rHC_Adapt) the calculation of the expected temperature change based on a difference (TExo_Dvt) between the actual temperature change and the expected temperature change (TExo_Mdl).