Abstract

The advent of plug-in hybrid electric vehicles (PHEVs) introduces a new vehicle paradigm that consumes both gasoline and electricity. The new concept presents new questions. In particular, (1) what modifications need to be made for test procedures in terms of the emissions and fuel economy measurements for individual vehicles, and (2) what methodology needs to be established to evaluate the energy and emission impacts of a PHEV fleet? For the test procedure, the emission testing has been done by using the continuous sampling method for continuous diluents, the smooth approach orifice (SAO) measurement for ambient air flow, and fuel flow meter (FFM) measurement for fuel consumption in addition to the industry standard constant volume sampler (CVS) system, which faces challenges for PHEVs. Results show that the current CVS dilution factor (DF) exhibits an error resulting in higher emission mass calculation; an alternative procedure can be proposed for the charge depleting cycle to eliminate the overdilution; the CVS system has an error resulting from exhaust left in the tailpipe and CVS sampling line. For the evaluation of the energy impact of PHEVs, the South Coast Air Basin of California (SoCAB) was selected as an example by considering different charging scenarios consisting of different charging powers, locations and time. Results show that petroleum reduction is significant; the all-electric ability is crucial to cold start emission reduction; the benefit of higher power charging is small; delayed and average charging are better than immediate charging for home; and non-home charging increases peak grid load.