Real-world environmental performance of hybrid vehicles

With the further development and market introduction of hybrid vehicle technologies in recent years we are now at a stage where we can test whether the proclaimed advantages of hybrid propulsion in terms of fuel efficiency and emission reduction are actually realised. An important issue is that significant efficiency and emission improvements should not only be realised under homologation test conditions, but also in real-world driving. TNO Automotive has tested the parallel-hybrid Honda Insight on the European Driving Cycle as well as on a set of real-world driving cycles representing various traffic conditions (from heavy congestion stop-and-go to free-flow highway driving) and driving styles (ranging from ecological to sportive). These cycles have been derived from recorded driving data using a statistical method developed by TNO Automotive, which ensures that the cycles are representive in terms of speed/ acceleration patterns. In the test procedure applied to the Honda Insight, the hybrid nature of the vehicle is explicitly taken into account. In this paper the results for the Honda Insight are compared to the average fuel consumption and emissions of a set of European mid-size and compact vehicles on the same set of driving cycles. Except for the NOx-emissions on a range of real-world cycles, the emission performance of the Insight is found to be significantly better than that of the average conventional gasoline car. Also the fuel consumption improvement measured under homologation conditions is reproduced under most real-world driving conditions.