A computer program was created to calculate fuel consumption and emissions of cars in real-time. It models how the engine and chassis interact, allowing for studying quick changes that steady-state models miss. The program can quickly assess how changes in vehicle parts affect fuel economy and emissions. It also includes a driver simulator to study human factors. The program accurately predicts fuel usage during different driving conditions, analyzes power train dynamics, and tracks energy usage throughout a drive. It provides valuable data on engine performance under different conditions.