A system for determining properties of fuel supplied to an internal combustion (IC) engine and for adjusting operations of the IC engine based on the determined properties. The system includes an air-flow throttle configured to control the air supplied to the IC engine; a fuel-flow throttle configured to control the fuel supplied to the IC engine; and an engine control module (ECM) configured to receive readings from and control operation of the throttles. The ECM is configured to perform a fuel-air determination program where the ECM determines a percent-error air-to-fuel ratio (AF) based on a true AF ratio compared to an ideal AF ratio. The ECM is configured to perform a fuel property determination and adjustment program in which the ECM is configured to adjust operations of the IC engine based on a fuel property value determined using the percent-error AF ratio.

A method for operating a motor vehicle with an internal combustion engine, comprising a combustion engine and an exhaust line with an exhaust aftertreatment system. At least one environmental emission of an exhaust component or multiple exhaust components, contained in the exhaust gas generated by the combustion engine, is determined. If a limitation threshold value for the environmental emission of the exhaust component or at least one of the exhaust components is exceeded, the operation of the combustion engine is limited with respect to the deliverable power. If a warning threshold value for the environmental emission of the exhaust component or at least one of the exhaust components, which is lower than the limitation threshold value, is exceeded, a warning message is triggered and/or the operation of the internal combustion engine is adapted in a power-neutral manner such that the environmental emission of the exhaust component is reduced.