Heater diagnostics in heavy-duty motor vehicle engines

A method, comprising:

• operating a heavy-duty diesel engine at steady state at a first set of operating conditions such that the heavy-duty engine generates a first exhaust gas flow;
• calculating a first rate at which heat energy is provided to the first exhaust gas flow from the heavy-duty engine and storing the calculated first rate at which heat energy is provided to the first exhaust gas flow from the heavy-duty engine as a first independent variable of a first entry in a lookup table;
• calculating a first rate at which heat energy is provided to the first exhaust gas flow from a heater and storing the calculated first rate at which heat energy is provided to the first exhaust gas flow from the heater as a second independent variable of the first entry in the lookup table;
• storing a first measured temperature of the first exhaust gas flow at a selective catalytic reduction system of the exhaust after-treatment system as an output of the first entry in the lookup table;
• operating the heavy-duty diesel engine at steady state at a second set of operating conditions that is different than the first set of operating conditions such that the heavy-duty engine generates a second exhaust gas flow;
• calculating a second rate at which heat energy is provided to the second exhaust gas flow from the heavy-duty engine and storing the calculated second rate at which heat energy is provided to the second exhaust gas flow from the heavy-duty engine as a first independent variable of a second entry in the lookup table;
• calculating a second rate at which heat energy is provided to the second exhaust gas flow from the heater and storing the calculated second rate at which heat energy is provided to the second exhaust gas flow from the heater as a second independent variable of the second entry in the lookup table;
• and
• storing a second measured temperature of the second exhaust gas flow at the selective catalytic reduction system of the exhaust after-treatment system as an output of the second entry in the lookup table.

A heavy-duty truck, comprising:

• a diesel engine;
• an exhaust after-treatment system having an upstream end and a downstream end opposite the upstream end, the upstream end coupled to the diesel engine, the exhaust after-treatment system including:
• a first temperature sensor;
• a heater downstream of the first temperature sensor;
• a second temperature sensor downstream of the heater;
• and
• a selective catalytic reduction system downstream of the second temperature sensor.