Submitted by Prof. D. Cebon on Sat, 25/05/2013 - 21:54
Will Midgley's PhD dissertation 'Regenerative Braking of Urban Delivery Heavy Goods Vehicles has been approved by the University.
The thesis investigated technologies for regenerative braking of heavy goods vehicles, and specifically the application of hydraulic hybrid technology to semitrailers with steered axles. The work was performed in collaboration with Poclain Hydraulics and other members of the Cambridge Vehicle Dynamics Consortium www.cvdc.org.
Summary
Regenerative braking has been shown to reduce the fuel consumption for vehicles by recovering energy during braking, and using this stored energy to accelerate the vehicle. This dissertation discusses the application of regenerative braking to an urban delivery heavy goods vehicle (HGV).
In Chapter 2, data are compiled on different energy storage methods—batteries, flywheels, hydraulic accumulators and compressed air—and methods for utilising this stored energy. These technologies are then ‘power-matched’ and compared, and hydraulic energy storage/actuation is found to be 16% lighter and 33% smaller than the nearest competing technologies.
Chapter 3 introduces a computer model of the vehicle constructed in MATLAB/Simulink. This model includes experimentally derived maps for the engine and pump/motor efficiency, and is used to specify a hydraulic regenerative braking system for an HGV tri-axle trailer. The specified system shows a reduction in fuel usage of 5-11% on legislative drive cycles and 5% on realistic hilly cycles.
Different control methods are discussed in Chapter 4, including both ‘greedy’ and ‘heuristic’ algorithms. The greedy algorithm is found to be the only algorithm capable of real-time operation. Model predictive control is implemented, but is seen as too unwieldy for this regenerative braking system, and a global optimisation technique—pattern search—is used to place a lower bound on the vehicle’s fuel usage.
Chapter 5 discusses the design and build of a practical hydraulic regenerative braking system for an urban delivery HGV.
Chapter 6 draws conclusions from the dissertation and suggests directions for future work.