Although plug-in Hybrid Electric Vehicles (pHEVs) can be considered a powerful technology to promote the change from conventional mobility to e-mobility, their real benefits, in terms of CO2 emissions, depend to a great extent on the average efficiency of their Internal Combustion Engine and on the energy source mix which is used to supply the electrical demand of pHEV.Furthermore the operating cost of the vehicle should also be taken into account in the design process, since it represents the main driver in the customer’s choice.This article has the purpose of assessing, through numerical simulations, the effects of different technology mixes used to produce electrical energy for the battery recharging, of different Internal Combustion Engines on the pHEV performance, and highlighting the main differences with respect to the regulatory test procedure

Several knock-detection methods, based both on cylinder pressure analysis and on engine block vibration analysis, have been carefully scrutinized through a critical review of the knock-detection techniques available in literature. Issues have been discussed regarding the physical meaning of knock intensity measurement indexes, mechanical noise sensitivity, transducer type and location, filtering-frequency bands and crank-angle window selection. An experimental investigation has been carried out on a typical European mass-produced engine, and this has provided criteria for the selection of the most suitable and reliable techniques, and has allowed a comparison between experimental results obtained by means of different knock-detection methods.

High pressure common-rail injection systems nowadays allow a very high degree of flexibility in the timing and quantity control of multiple injections, which can be used to obtain significant reductions in engine noise and emissions. The aim of this study is to develop a better understanding of the relationship between injection strategies and the combustion and emission formation process. Some multiple injection strategies (pilot-pilot-main and pilot-main-after) have therefore been analyzed to highlight their influence on soot, NOx, combustion noise and bsfc (brake specific fuel consumption) on a passenger car DI Diesel engine prototype. One operating point (2000×2 rpm/bar) was analyzed for the pilot-pilot-main injection strategy while two operating points (1500×5 and 2500×8 rpm/bar) were tested for the pilot-main-after injection strategy. Finally the main combustion characteristics were determined, for each operating condition, on the basis of the heat release and a correlation was attempted between the combustion parameters and emissions, noise and bsfc.