Improvement of Citybus Fuel Economy Using a Hydraulic Hybrid Propulsion System - A Theoretical and Experimental Study

Buchwald, Paweł; Christensen, Georg Kronborg; Larsen, Helge V.; Pedersen, Peter Sunn

doi:10.4271/790305

Cited by 29 publications

(16 citation statements)

References 2 publications

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“…Consequently, power flows through the hybrid sub system can be very high. This makes hydraulic propulsion and storage components very attractive for truck applications, since they are characterized by much higher power density compared to their electric counterparts [1]. As the energy storage device, hydraulic accumulator has the ability to accept high rates and high frequencies of charging/discharging, both of which are not favor able for batteries.…”

Section: Introductionmentioning

confidence: 99%

“…Early studies attempted to use engineering intuition to devise control strategies. Buchwald and others [ 1] evaluated three different strategies on city buses considering simple vehicle acceleration -deceleration profiles. Wu et al [2] proposed a strategy for passenger cars based on dividing the accumulator volume into two parts, one for regeneration and the other for road-decoupling.…”

Section: Introductionmentioning

confidence: 99%

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Optimal Power Management for a Hydraulic Hybrid Delivery Truck

Lin

Filipi³

et al. 2004

Vehicle System Dynamics

190

132

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SUMMARYHydraulic hybrid propulsion and energy storage components demonstrate characteristics that are very different from their electric counterparts, thus requiring unique control strategies. This paper presents a methodology for developing a power management strategy tailored specifically to a parallel Hydraulic Hybrid Vehicle (HHV) configured for a medium-size delivery truck.The Hydraulic H ybrid Vehicle is modelled in the MATLAB/SIMULINK environment to facilitate system integration and control studies . A Dynamic Programming (DP) algorithm is used to obtain optimal control actions for gear shifting and power splitting bet ween the engine and the hydraulic motor over a representative urban driving schedule . Features of optimal trajectories are then studied to derive i mplementable rules . System behaviour demonstrates that the new control strategy takes advantage of high power density and efficiency characteristics of hydraulic components, and minimizes disadvantages of low energy density, to achieve enhanced overall efficiency . Simulation results indicate that the potential for fuel economy improvement of medium trucks with hydraulic hybrid propulsion can be as high as 48 %.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimal Power Management for a Hydraulic Hybrid Delivery Truck

Lin

Filipi³

et al. 2004

Vehicle System Dynamics

190

132

View full text Add to dashboard Cite

show abstract

“…As computing power increased, researchers began developing simulations and trying different control strategies for city buses to improve fuel economy [2]. Research has also been done using models of hydraulic hybrid military vehicles, optimal control theory, and numerical algorithms to determine drive train parameters to minimize fuel consumption [3].…”

Section: Introductionmentioning

confidence: 99%

Optimization of a Passenger Hydraulic Hybrid Vehicle to Improve Fuel Economy

Stelson

Meyer

Alleyne

et al. 2008

Proceedings of the JFPS International Symposium on Fluid Power

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This paper investigates power management strategies for hydraulic hybrid passenger vehicles. Parallel, series, and power-split architectures are modeled and explored in the Matlab environment using variable efficiency hydraulic pump/motor models. Results are presented using a rule-based strategy with ad hoc selection of engine on/off setpoints for the accumulator and transmission gear shifting. The dynamic programming algorithm is then used to determine the optimal trajectories for engine/hydraulics power splitting for each of the architectures over urban and highway drive cycles. Results are then compared to baseline simulation for improvement. Using the given vehicle parameters, the parallel architecture for both the urban and highway drive cycles was shown to be best. By decreasing the volumetric displacement of the hydraulic pump/motors for the power-split configuration, fuel economy can be improved with a corresponding decrease in acceleration.KEY WORDS

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“…Indeed, early research and development, at least partially motivated by the 1970s oil crises, was focused on city buses, such as for example the MAN Hydro-Bus [17], the Cumulo Brake Energy Drive developed and tested for buses and its hydrostatic successor [18,19], studies at the Technical University of Denmark (cf. [20] with further reporting in [21]), and Mitsubishi's buses with brake energy recuperation [22]. Passenger vehicles have nonetheless been subject to research activity (cf.…”

Section: Applicationsmentioning

confidence: 99%

“…e.g. [20,47,24,22]). Nowadays, increased computational power both online and offline has led to a multitude of control approaches, which can be classified (for example) based on the optimality of the control approach and the control and prediction horizon [48,49].…”

Section: Control Of Hydraulic Hybrid Transmissionsmentioning

confidence: 99%

Simulation-Based Optimization of a Series Hydraulic Hybrid Vehicle

Bær¹

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"The brick walls are there for a reason. (...) [They] are there to give us a chance to show how badly we want something. Randy Pausch AbstractHybrid transmissions are characterized by their utilization of more than one form of energy storage. They have the potential to help reduce overall fuel consumption and vehicle emissions by providing the possibility of brake energy recuperation and prime mover operation management. Electric hybrids and electric vehicle drives are nowadays ubiquitous, and mechanical energy storage in flywheel has been investigated in the past. The use of fluid power technology with a combustion engine has also been investigated since the late 1970s, and is frequently revisited.Hydraulic hybridization is especially attractive for heavy vehicles with frequent braking and acceleration which benefit most from fluid power components' high power density, typically busses, delivery or refuse vehicles, and vehicles with existing hydraulic circuits and transmissions, such as forest and construction machinery, but have been considered for smaller vehicles as well.Due to the characteristic discharge profile of hydraulic energy storage, special attention needs to be paid to control aspects in the design process to guarantee drivability of the vehicle. In this respect, simulation models can be of use in early design process stages for cheaper and faster evaluation of concepts and designs than physical experiments and prototyping, and to generate better understanding of the system studied. Engineering optimization aids in the systematic exploration of a given design space, to determine limits and potentials, evaluate trade-offs and potentially find unexpected solutions. In the optimization of a hydraulic hybrid transmission, the integration of component and controller design is of importance, and different strategies (sequential, iterative, bi-level and simultaneous approaches) are conceivable, with varying consequences for the implementation.This thesis establishes a simulation-based optimization framework for a hydraulic hybrid transmission with series architecture. Component and control parameter optimization are addressed simultaneously, using a rule-based supervisory control strategy. The forward-facing dynamic simulation model at the centre of the framework is built in Hopsan, a multi-disciplinary open-source tool developed at Linköping University. The optimization is set up and conducted for an example application of an on-road light-duty truck over standard drive i cycles. Both results from these experiments as well as the framework itself are studied and evaluated. Relevant design aspects, such as explicit design relations to be considered and performance requirements for more robust design, are identified and addressed, and the optimization problem is analysed with regard to algorithm performance and problem formulation. The final result is an optimization framework that can be adjusted for further in-depth studies, for example through the inclusion of additional components or optimization obj...

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Improvement of Citybus Fuel Economy Using a Hydraulic Hybrid Propulsion System - A Theoretical and Experimental Study

Cited by 29 publications

References 2 publications

Optimal Power Management for a Hydraulic Hybrid Delivery Truck

Optimal Power Management for a Hydraulic Hybrid Delivery Truck

Optimization of a Passenger Hydraulic Hybrid Vehicle to Improve Fuel Economy

Simulation-Based Optimization of a Series Hydraulic Hybrid Vehicle

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