APPARATUS AND METHOD FOR DIAGNOSING AN ENGINE USING AN EXHAUST TEMPERATURE MODEL

An apparatus and method for diagnosing an engine including at least two cylinder banks using an exhaust temperature model is disclosed. The apparatus and method are operable for: (a) determining an actual exhaust temperature value for the first cylinder bank, an actual exhaust temperature value for the second cylinder bank, and an average exhaust temperature value for the first and second cylinder banks; (b) determining a plurality of parameters; (c) determining a modeled exhaust temperature value for the first cylinder bank, a modeled exhaust temperature value for the second cylinder bank, and a modeled average exhaust temperature value for the first and second cylinder banks, as a function of the plurality of parameters; (d) comparing the modeled and actual exhaust temperature values for the first cylinder bank, comparing the modeled and actual exhaust temperature values for the second cylinder bank, and comparing the modeled and actual average temperature values, and responsively determining a difference value for the first cylinder bank, a difference value for the second cylinder bank, and an average difference value, respectively; and (e) diagnosing the engine as a function of at least one of the difference value for the first cylinder bank, the difference value for the second cylinder bank, and the average difference value.