Cycle Beating - An Analysis of the Boundaries During Vehicle Testing

Abstract

Todays vehicle industry is strictly controlled by environmental legislations. The vehicle industry is spending much money on reducing the fuel consumption and fulfilling the emission requirements to make sales possible in different regions in the world. Before introducing a vehicle on the market, it is tested according to standardized driving cycles to specify the vehicle pollutant emissions and fuel consumption. These cycles allow some deviation from the reference vehicle speed during tests, e.g. NEDC allows deviations of ±2 km/h and ±1 s. This paper uses dynamic programming to find fuel optimal velocity profiles, given the allowed deviations of ±2 km/h and ±1 s from reference speed during drive cycle test. By taking advantage of the allowed deviation, the fuel consumption can be reduced by up to 16.56 % according to model results, running NEDC if gear selections are unrestricted (i.e. using automatic gearbox), and up to 5.90 % if changing gears according to the specifications in the drive cycle. Two different optimization goals are investigated, minimum amount of mass fuel consumed and best mileage.