Development of processing methodologies used to form complete driving-cycle dynamometer tests based on urban on-road driving and road gradient data

Abstract

This work involves the development of ‘real-world’ driving cycles using on-road data from the greater area of Athens, Greece. Two different methodologies of driving-cycle development are presented here, based on the MATLAB code. Driving patterns from various test vehicles were processed to form driving cycles consisting of a specific number of driving periods. The main criterion for the design and acceptance of each method was the correlation of the resulting driving cycles with the corresponding characteristics of the processed road data. Time is an important issue when processing data. Applying the same set of data to both methods, method A needed 5 h to complete the processing compared with 9 s for method B. The corresponding average accuracies were 99.9% and 97.2% respectively. The road gradient was taken into account for the development of the driving cycles. For method A, the road gradient was included in the final result by intervening in the mean positive accelerations and the mean negative accelerations. Those were increased by 11.99% and 16.06% respectively for the Greek Urban Driving Cycle for Motorcycles. For method B, the road gradient was assimilated by a ‘load cycle’ expressed in kilowatts and used in combination with the developed driving cycle, thus forming a complete chassis dynamometer test. The load cycle was produced by calculating the power related to the vehicle’s mass that holds or assists it when driving uphill or downhill. The Greek Urban Driving Cycle for Motorcycles was developed using method A. Its characteristics include the follwoing: a duration of 822 s, an average speed of 28.86 km/h, a stop-time percentage of 12.04 and a positive acceleration of 0.6065 m/s2. Method B was used for the Greek Urban Driving Cycle for passenger cars. Some of its characteristics include the following: a duration of 1175 s, an average speed of 18.67 km/h, a stop-time percentage of 31.66 and a positive acceleration of 0.692 m/s2.