Impacts of AMT Gear-Shifting on Fuel Optimal Look Ahead Control
2009 (English)Report (Other academic)
A fuel optimal gear shift control has been studied, when look ahead information is available, and the impact of the automated manual transmission (AMT) gear-shifting process is analayzed. For a standard discrete heavy truck transmission, answers are found on when to shift gears, prior to or when in an uphill slope. The gear-shifting process of a standard AMT is modeled, not considering the comfort details, in order to capture the fuel and time aspects of the gear shift. A numerical optimization is performed by dynamic programming, minimizing fuel consumption and time by controlling fuel injection and gear. Since a standard AMT does not have look ahead information, it sometimes gears down unnecessarily and thus gives a significantly higher fuel consumption compared to the optimal control. However, if gearing down is inevitable, the AMT gear-shifting strategy, based on engine thresholds, is a well-functioning gear control so that the optimal control only gives marginal additional savings. To attain the possible fuel reductions it is shown that the reduced propulsion of an AMT gear-shifting process, and the resulting vehicle retardation, must be considered. The point of shifting gears must be chosen to ensure an adequate engine speed in order to get a sufficient engine power after the gear shift, even as the truck is decelerated during gear shift.
Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press , 2009. , 14 p.
LiTH-ISY-R, ISSN 1400-3902 ; 2883
National CategoryEngineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-18189ISRN: LITH-ISY-R-2883DOI: 10.4271/2010-01-0370OAI: oai:DiVA.org:liu-18189DiVA: diva2:216643