Search Results

Current-production hybrid electric vehicles (HEVs) have shown a measurable improvement in fuel economy, in comparison with conventional vehicles, by using the internal combustion engine in a more efficient operating region, which therefore reduces petroleum consumption. These HEVs operate with a charge-sustaining control strategy. Plug-in HEVs (PHEVs) show the potential to further decrease petroleum consumption by operating in a charge-depletion control strategy, in which the energy stored in the battery pack in used during normal driving and recharged through stationary, off-board vehicle charging. This charge-depletion strategy uses more electrical energy to propel the vehicle, which displaces more petroleum. This paper discusses the testing and analysis of a Hymotion Prius PHEV, an Energy CS Prius PHEV, and a Renault Kangoo PHEV.

Hybrid electric vehicles (HEVs) may have key fuel economy and emissions advantages over current conventional vehicles, but they have drawbacks such as frequent engine starts that can slow down market penetration of HEVs. First, the hydrocarbon emissions due to the numerous engine starts would make newly developed HEV powertrains even more demanding on the emission control system. Second, frequent starts may make the engine deteriorate quickly. This study is an attempt to gain a better understanding of the engine start characteristics of two limited-production HEVs (Toyota Prius and Honda Insight). Using fast-response (5 ms) hydrocarbon and NO (nitric oxide) analyzers, the transient emissions were measured in the engine exhaust ports during cold and hot engine starts. On the basis of the experimental findings, several recommendations were made to improve performance and emissions of future HEVs.