Abstracts Category : Other

Fuel optimizing cruise controller with driveability

by Linnea Hllerstam Jonsson

This thesis work is based on a dynamic programming solution of a fuel optimizing cruise controller that was developed at Scania CV AB last year. Known data of the road ahead, mainly the slope, is used to continuously calculate the optimal torque and gear choices of a given moving vehicle for a certain horizon. The optimization calculations are based on fuel consumption and the vehicle's arrival time to the final destination. This report has been focused on achieving better "driveability" of the cruise controller while still maintaining the good fuel saving qualities that is already there. Simulation is used to evaluate the cruise controller on roads where the wanted data is known. The result is smaller speed variations on at road segments, which will improve a driver's impression of the cruise controller. The great fuel benefits of using roll-techniques in hilly areas is maintained from the previous implementation. The key to the optimal balance between these two behaviors is found using a method that limits the torque usage of the truck to a certain speed interval and then finds exception areas where the torque usage should be unlimited. Detta examensarbete r baserad p en dynamisk programmeringslsning av en brnsleoptimerande farthllare som utvecklades p Scania CV AB frra ret. Knd data om den framfrvarande vgen, s som lutningen, anvnds fr att berkna optimalt drivmoment och vxelval fr ett givet fordon fr en viss horizont. Optimeringsberkningarna baseras p brnslefrbrukning och fordonets ankomsttid till mlet. Denna rapport focuserar p att uppn bttre "krbarhet" fr farthllaren och samtidigt behlla de goda brnslebesparande egenskaper som farthllaren redan har. Simulering nyttjas fr att analysera farthllaren p vgar dr nskad data r knd. Resultatet r mindre hastighetsvariationer p platta vgar, vilket br frbttra frarens uppfattning av farthllaren. De stora frdelar som kommer med anvndning av rull-tekniker p kuperade vgstrckor bevaras frn den tidigare implementeringen. Nyckeln till optimal balans mellan dessa tv krbeteenden r en metod som gr ut p att begrnsa fordonets momentanvndning till ett visst hastighetsinterval och sedan hitta undantagsomrden dr momentanvndning borde vara obegrnsad.