ABSTRACT
Internal combustion (IC) engines are energy conversion devices that extract storedenergyinafuelthroughthecombustionprocessanddelivermechanicalpower.Thedevicesarealsoknownasheatenginesinthebroader sense.Reciprocating-typeICengineistheprimarychoiceofpowerplantin today’sproductionhybridvehicles.TheICengineisassistedbyanelectric motor of similar or lower power capability in these vehicles. IC engines for conventionalvehiclesaredesignedtooperateoverawiderange,andcompromiseisoftennecessarytodeliveracceptableef‹ciencyandperformance throughoutitsoperationregime.Ontheotherhand,ICenginesinhybrid vehiclesrequireoperationwithinanarrowbandoftorque-speedcharacteristics, especially in those with series-type hybrid architectures. However, ICenginesareyettobedesignedspeci‹callyforhybridvehicles;signi‹- cantopportunityexiststoexploreimprovedICenginedesignsforhybrid vehicles.
