Development of a Fuel Consumption Test Procedure for Representative Urban Duty Cycles 2011-01-2291

This project's objective was the development of an on-road vehicle fuel consumption test procedure for representative stop-and-go urban duty cycles. The scope of the project included a review of existing stop-and-go urban duty cycles, the development of a track testing methodology for measuring the fuel consumption on stop-and-go urban duty cycles, and testing with a view to the validation of the methodology.

Literature review analyzed several transport activities to determine specific stop-and-go urban duty cycles, such as pick-up and delivery operations, refuse collection, bus transport, and utility and service operation. It was found that driving cycles should be easy enough to recreate and replicate on the test track and should be representative of application driving patterns. The cycles should be adapted for fuel economy testing, and geometric cycles are easier to follow than the cycles based on actual drive traces. Based on these findings, duty cycles' characteristics, such as driving cycle (defined as speed versus distance traces), vehicles specifications, and representative loads, were determined.

The proposed test methodology has two sections: fuel consumption measurement tests, and comparative tests for evaluating the modification in fuel efficiency. Validation tests were conducted on the test track for the measurement methodology with both pick-up and delivery and refuse collection cycles, while the comparative testing methodology was evaluated with the pick-up and delivery cycle only. The tests showed that it is feasible to conduct stop-and-go fuel consumption tests on the test track. The repeatability can be assured, but driver fatigue could be an important factor that impedes on the constancy: automatic or automated transmissions are highly recommended for all the test vehicles. Whilst the duration of a run was sufficient and helps to minimize the influence of driver fatigue, the corresponding length and consumed fuel were low, and it is recommended to double the number of cycles for a test run.