System and method for determination of EGR flow rate

1. Field of the Invention A system and method for determining EGR flow in a multi-cylinder internal combustion engine include determining specific heat of the exhaust gas based on current engine operating conditions and determining EGR flow rate based on the determined specific heat and a signal provided by a sensor. In one embodiment, a species tracking model is used to determine the amount of various species within the exhaust gas which may include oxygen, nitrogen, carbon dioxide, and water, for example, to determine the current specific heat, which is compared to a reference specific heat for the sensor, the difference being used to adjust the sensor value and determine the EGR mass flow rate. The species tracking model uses a simplified combustion model to estimate the amount of each specie in the exhaust gas based on various engine operating parameters, such as fuel, air/fuel ratio, and turbo boost, for example.