Influence of Hydraulic Accumulator Performance on the Hydraulic Hybrid Powertrain

2019 ◽  
Author(s):  
Qi Zhang ◽  
Feng Wang ◽  
Bing Xu ◽  
Kim A. Stelson
Keyword(s):  
Thermal Hysteresis ◽  
Hybrid Powertrain ◽  
Actual Performance ◽  
Wheel Loader ◽  
Accumulator Model ◽  
Hydraulic Hybrid ◽  
Dynamic Simulation Model ◽  
The Difference ◽  
Hydraulic Accumulator ◽  
Accumulator Models

Abstract Owing to its high power density, hydraulic hybrid is considered as an effective approach to reducing the fuel consumption of heavy duty vehicles. A gas-charged hydraulic accumulator serves as the power buffer, storing and releasing hydraulic power through gas. An accurate hydraulic accumulator model is crucial to predict its actual performance. There are two widely used accumulator models: isothermal and adiabatic models. Neither of these models are practical to reflect its real performance in the hydraulic hybrid system. Therefore, the influence of an accumulator model considering thermal hysteresis on a hydraulic hybrid wheel loader has been studied in this paper. The difference of three accumulator models (isothermal, adiabatic and energy balance) has been identified. A dynamic simulation model of the hydraulic hybrid wheel loader has been developed. The fuel consumptions of the hydraulic hybrid wheel loader with three accumulator models has been compared. The influence of heat transfer coefficient of the accumulator housing has also been studied.

Modeling and Design of a Series Hydraulic Hybrid Powertrain for Compact Wheel Loaders

2018 ◽  
Author(s):  
Qunya Wen ◽  
Feng Wang ◽  
Bing Xu
Keyword(s):  
Speed Control ◽  
Torque Control ◽  
Vehicle Speed ◽  
Energy Management Strategy ◽  
Hybrid Powertrain ◽  
Engine Torque ◽  
Wheel Loader ◽  
Hydraulic Hybrid ◽  
Wheel Loaders ◽  
Hydraulic Accumulator

As an effective approach to improving the fuel economy of modern heavy-duty vehicles, hydraulic hybrids have shown great advantages in off-road vehicles. Wheel loader is one of the representative vehicles in off-road applications as they are usually designed for single and repetitive task such as loading material. In a typical short loading cycle, there are many accelerations and decelerations, showing great hybridization potentials. Therefore in this paper a series hydraulic hybrid powertrain has been proposed for compact wheel loader since its hydrostatic powertrain can be easily transformed to a series hydraulic hybrid with an additional hydraulic accumulator. The modeling and system design of the series hydraulic hybrid wheel loader have been presented. Three controllers have been designed for vehicle speed control, engine torque control and engine speed control respectively. A dynamic simulation model has been developed in MATLAB/Simulink. A rule-based energy management strategy (EMS) has been proposed for the series hydraulic hybrid wheel loader. Two different EMS schemes were investigated and compared through simulation studies.

Power Optimization of Series Hydraulic Hybrid Powertrain for Compact Wheel Loader

2019 ◽  
Author(s):  
Qunya Wen ◽  
Feng Wang ◽  
Bing Xu ◽  
Zongxuan Sun
Keyword(s):  
Energy Management ◽  
Fuel Economy ◽  
Management Strategy ◽  
Power Optimization ◽  
Parameter Study ◽  
Energy Management Strategy ◽  
Hybrid Powertrain ◽  
Wheel Loader ◽  
Hydraulic Hybrid ◽  
Equivalent Consumption Minimization Strategy

Abstract As an effective approach to improving the fuel economy of heavy duty vehicles, hydraulic hybrid has shown great potentials in off-road applications. Although the fuel economy improvement is achieved through different hybrid architectures (parallel, series and power split), the energy management strategy is still the key to hydraulic hybrid powertrain. Different optimization methods provide powerful tools for energy management strategy of hybrid powertrain. In this paper a power optimization method based on equivalent consumption minimization strategy has been proposed for a series hydraulic hybrid wheel loader. To show the fuel saving potential of the proposed strategy, the fuel consumption of the hydraulic hybrid wheel loader with equivalent consumption minimization strategy was investigated and compared with the system with a rule-based strategy. The parameter study of the equivalent consumption minimization strategy has also been conducted.

scholarly journals Numerical analyses of a hydraulic hybrid powertrain system for a transit bus

2020 ◽  
Vol 24 (1 Part A) ◽  
pp. 159-170
Author(s):  
Marko Kitanovic ◽  
Slobodan Popovic ◽  
Nenad Miljic ◽  
Predrag Mrdja
Keyword(s):  
Dynamic Programming ◽  
Fuel Economy ◽  
Model Parameters ◽  
Hybrid Powertrain ◽  
Hydraulic Hybrid ◽  
Powertrain System ◽  
Improvement Potential ◽  
Fuel Economy Improvement ◽  
Hydraulic Accumulator ◽  
Transit Bus

A dynamic programming optimization algorithm has been applied on a transit bus model in MATLAB in order to assess the fuel economy improvement potential by implementing a hydraulic hybrid powertrain system. The numerical model parameters have been calibrated using experimental data obtained on a Belgrade?s public transport bus. This experiment also provided the representative driving cycle on which to conduct simulation analyses. Various functional parameters of a hydraulic hybrid system have been evaluated for obtaining the best possible fuel economy. Dynamic programming optimization runs have been completed for various hydraulic accumulator sizes, preload values and accumulator foam quantities. It has been shown that a fuel economy improvement of 28% can be achieved by implementing such a system.

Online optimization of Pontryagin’s minimum principle for a series hydraulic hybrid wheel loader

2021 ◽  
pp. 095440702110398
Author(s):  
Qi Zhang ◽  
Feng Wang ◽  
Bing Xu ◽  
Zongxuan Sun
Keyword(s):  
Dynamic Programming ◽  
Fuel Consumption ◽  
Minimum Principle ◽  
Pontryagin’S Minimum Principle ◽  
Energy Management Strategy ◽  
Hybrid Powertrain ◽  
Rule Based ◽  
Wheel Loader ◽  
Hydraulic Hybrid ◽  
Pontryagin's Minimum Principle

The hydraulic hybrid powertrain has great potential for reducing fuel consumption and emission of off-road vehicles. The energy management strategy is the key to hybrid powertrain and currently there are many well-developed strategies. Of which the Pontryagin’s minimum principle is of research interest since it is a global optimization method while less computational burden than dynamic programming. However, it requires full cycle information to calculate co-state value in the principle, making it not implementable. Therefore in this study an implementable Pontryagin’s minimum principle is proposed for a series hybrid wheel loader, where the optimal co-state value in the principle is trained through repetitive wheel loader duty cycle. The Pontryagin’s minimum principle formulations of hybrid wheel loader are developed. The online co-state training algorithm is presented. A dynamic simulation model of hybrid wheel loader is developed. The fuel consumption of hybrid wheel loader with proposed strategy is compared with dynamic programming strategy and rule-based strategy in wheel loader long and short loading cycles. Results show the fuel consumption with proposed strategy is close to dynamic programming result and is lower than rule-based strategy. Finally, the influence of pressure level of hybrid powertrain on vehicle fuel consumption is studied.

Modeling and Design of a Hydraulic Hybrid Powertrain for Passenger Vehicle

2017 ◽  
Author(s):  
Haoxiang Zhang ◽  
Feng Wang ◽  
Kim A. Stelson
Keyword(s):  
Energy Management ◽  
Management Strategy ◽  
Controller Design ◽  
Mechanical Transmission ◽  
Passenger Vehicle ◽  
Energy Management Strategy ◽  
Hybrid Powertrain ◽  
Hydraulic Hybrid ◽  
Hydraulic Accumulator ◽  
Pressure Controlled

A hydraulic hybrid powertrain for passenger vehicle is studied in this paper. The hydraulic hybrid powertrain consists of a hydro-mechanical transmission and a hydraulic accumulator. The key component of this hydro-mechanical transmission is a pressure-controlled hydraulic transmission. It combines pumping and motoring function in one unit and is potentially more competitive in terms of both energy efficiency and cost effectiveness than a conventional hydrostatic transmission. By feeding the output flow of the pressure-controlled hydraulic transmission to a variable displacement motor coupled to the transmission output shaft, a more compact and simpler hydro-mechanical transmission is constituted. In this paper the systematic approach of applying the hydraulic hybrid powertrain to a passenger vehicle is studied. A dynamic simulation model is developed in Simulink and the U.S. EPA’s urban cycle is used as the test driving cycle. A rule-based energy management strategy (EMS) for the hydraulic hybrid powertrain has also been developed. The system parameter design, controller design and the energy management strategy are evaluated through simulation.

Improving the Fuel Efficiency of Compact Wheel Loader With a Series Hydraulic Hybrid Powertrain

2020 ◽  
Vol 69 (10) ◽  
pp. 10700-10709
Author(s):  
Qunya Wen ◽  
Feng Wang ◽  
Bing Xu ◽  
Zongxuan Sun
Keyword(s):  
Fuel Efficiency ◽  
Hybrid Powertrain ◽  
Wheel Loader ◽  
Hydraulic Hybrid

Predictive Energy Management for Parallel Hydraulic Hybrid Passenger Vehicle

2010 ◽  
Author(s):  
Timothy O. Deppen ◽  
Andrew G. Alleyne ◽  
Kim A. Stelson ◽  
Jonathan J. Meyer
Keyword(s):  
Energy Management ◽  
Hybrid Vehicle ◽  
Management Problem ◽  
Transfer Energy ◽  
Hybrid Powertrain ◽  
Engine Torque ◽  
Engine Simulation ◽  
Hydraulic Hybrid ◽  
Displacement Pump ◽  
Hydraulic Hybrid Vehicle

In this paper, a model predictive control (MPC) approach is presented for solving the energy management problem in a parallel hydraulic hybrid vehicle. The hydraulic hybrid vehicle uses variable displacement pump/motors to transfer energy between the mechanical and hydraulic domains and a high pressure accumulator for energy storage. A model of the parallel hydraulic hybrid powertrain is presented which utilizes the Simscape/Simhydraulics toolboxes of Matlab. These toolboxes allow for a concise description of the relevant powertrain dynamics. The proposed MPC regulates the engine torque and pump/motor displacement in order to track a desired velocity profile while maintaining desired engine conditions. In addition, logic is applied to the MPC to prevent high frequency cycling of the engine. Simulation results demonstrate the capability of the proposed control strategy to track both a desired engine torque and vehicle velocity.

scholarly journals PSX-35 Late-Breaking Abstract: Use of total tract NDF and starch digestibility in beef cow and replacement heifer diet formulation

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 354-354
Author(s):  
Garland Dahlke ◽  
Devin Jakub ◽  
John Goeser ◽  
Erika L Lundy
Keyword(s):  
T Test ◽  
Neutral Detergent Fiber ◽  
Starch Digestibility ◽  
Energy Estimates ◽  
Actual Performance ◽  
Average Bias ◽  
Beef Cow ◽  
Commercial Laboratory ◽  
Diet Formulation ◽  
The Difference

Abstract The objective of this trial was to evaluate the effectiveness of using the total tract neutral detergent fiber (TTNDFd) and starch digestibility methodology in the formulation of beef cow and replacement heifer rations. This methodology ultimately applies to the estimation of energy availability to the animal and accompanied performance as outlined by the NASEM 2016 Nutrient Requirements of Beef Cattle publication. Multiparous, Angus cows during the last two months of gestation and yearling replacement, Shorthorn heifers comprised the study. Cows received one of four, dry ingredient diets while heifers received a corn silage-based diet. Feed nutrient evaluation along with intake were documented and applied to the NASEM model for these cattle. Results were compared to actual performance. Acid detergent fiber (ADF) derived energy estimates which generally accompany commercial laboratory feed analysis reports were compared as well. A T-test between actual and projected growth was used to describe the difference. The T-test between the TTNDFd/Starch derived results did not show any statistical difference between the actual and projected results for heifers P(T< =t) 0.15 with an average ADG bias of -0.06 Kg. The cow results over the four diets P(T< =t) ranged from 0.41 to 0.004 with an average bias of 0.04 to 0.27 Kg overestimating ADG. The T-test between the ADF derived results showed a difference between the actual and estimated values for heifers P(T< =t) 0.0004 with an average ADG bias of 0.2 Kg. The cow results over the four diets likewise over estimated available energy substantially. Here the test ranged from P(T< =t) 0.03 to 0.0001 with an average bias of 0.35 to 0.7 Kg. It appears that TTNDFd methodology should be strongly considered in the evaluation of forages and in the development of ration formulation software for beef offered high levels of fiber in their ration.

scholarly journals Identity or Prestige: The Chameleon Effect on EFL Pronunciation

2018 ◽  
Vol 8 (2) ◽  
pp. 82
Author(s):  
Hanan Taqi ◽  
Nada Algharabali ◽  
Dalal Almubayei
Keyword(s):  
Kuwait University ◽  
Actual Performance ◽  
Male And Female ◽  
Short Questionnaire ◽  
International Language ◽  
Chameleon Effect ◽  
Language Knowledge ◽  
The Difference ◽  
A Current

Although there is a current tendency to deal with English as an international language, EFL pronunciation seems to be motivated by conceptions on identity and prestige. In this respect, the following study investigates the effect of identity and/or prestige on EFL speakers' English speech (or usage) in two different settings. Male and female participants from Kuwait University (63 in total), were given debate topics to engage in. Both their meetings and actual debates were recorded. The participants also filled a short questionnaire. The recordings were analyzed using Praat, while the questionnaire results were obtained using SPSS. The results show that the EFL speakers use different accents and various realizations of English consonants as a reflection of what is known as the Chameleon Effect. This study aims at helping teachers understand the difference between the speakers’ language knowledge and their actual performance.

Sign in / Sign up

Export Citation Format

Share Document