Transportation: Vehicle Power andPerformanceTheparametersofvehicledesignthatleadtoincreasedfueleconomy include low values of vehicle mass m, drag areaproduct C,A, and rolling resistance coefficient CrRecovery of vehicle kinetic energy during deceleration forreuse during other portions of the driving cycle will alsoimprovevehiclefueleconomy
Transportation: Vehicle Power and Performance • The parameters of vehicle design that lead to increased fuel economy include low values of vehicle mass m, drag area product CDA, and rolling resistance coefficient CR • Recovery of vehicle kinetic energy during deceleration for reuse during other portions of the driving cycle will also improve vehicle fuel economy
Transportation: Vehicle Power andPerformanceThetransmissionis a deviceattachedto the enginethatprovides stepped speedsto the drive shaft that connectsit tothewheelsTherearetwoformsoftransmission:manualandautomaticIn amanualtransmission,thevehicle operator disengagesa clutch (脱开离合器)and manuallyshifts toa differentgear before engagingtheclutchagain一Inanautomatictransmission,afluidcoupling（液压耦合装置）replacesthe clutchandgearshifting(换档)is accomplishedbycomputer-controlledhydraulicactuators（液压执行器）Themoreoperator-friendlyautomatictransmissionislessefficient than the manual one by about 1o percentage points
Transportation: Vehicle Power and Performance • The transmission is a device attached to the engine that provides stepped speeds to the drive shaft that connects it to the wheels • There are two forms of transmission: manual and automatic – In a manual transmission, the vehicle operator disengages a clutch (脱 开离合器) and manually shifts to a different gear before engaging the clutch again – In an automatic transmission, a fluid coupling (液压耦合装置) replaces the clutch and gear shifting (换档) is accomplished by computer-controlled hydraulic actuators (液压执行器) • The more operator-friendly automatic transmission is less efficient than the manual one by about 10 percentage points
Transportation: Vehicle Power andPerformanceTransmissionwithafive-speed+reversegearbox
Transportation: Vehicle Power and Performance Transmission with a five-speed + reverse gearbox