ANALYSIS OF ENERGY EFFICIENT SOLUTIONS FOR MODERN AGRICULTURAL MACHINES

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1020198
• Project Start Date: Oct 1, 2019
• Project End Date: Sep 30, 2024
• Program Code: [(N/A)]- (N/A)

Recipient Organization
PURDUE UNIVERSITY
(N/A)
WEST LAFAYETTE,IN 47907

Performing Department
Ag & Biological Engineering

Non Technical Summary
The goal of this research is to formulate and providing design criteria for a novel energy-efficient architecture for the actuation system of the next generation of agricultural machines which make use of electrification.The proposed system combines fluid power (FP) technology with electric technology, in a solution that allows reducing energy consumption of the traditional hydraulic actuation system up to 40% with respect to current state-of-art agricultural machines. The proposed solution will establish a modern design concept for the hydraulic actuation system of tractors that maximizes the advantages of FP technology while maintaining compatibility with current implements (planters, sprayers, tillage equipment, etc.).The concept idea is to change the current state-of-art design technology based on inefficient centralized hydraulic systems and make use of a distributed electro-hydraulic system design architecture. This allows reducing losses due to fluid throttling, internal energy storage through hydraulic accumulators and/or electric batteries, as well as a better matching with the hydraulic system of the common implements. The proposed technology has the potentials to result in a significant downsizing of the thermal engine - if not the entire elimination of it. The five-year plan of research includes both numerical modeling as well as experiments at the PD's lab (the Maha Fluid Power Research Center). Up to two different architectures for high energy efficiency solutions, original in the field of agricultural machines, will be simulated and tested.

Animal Health Component

40%

Research Effort Categories

Basic

60%

Applied

40%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
402	5310	2020	100%

Knowledge Area
402 - Engineering Systems and Equipment;

Subject Of Investigation
5310 - Machinery and equipment;

Field Of Science
2020 - Engineering;

Keywords

fluid power systems

agricultural tractors

high pressure hydraulic systems

fuel consumption

energy efficiency

electrification

Goals / Objectives
The proposed effort will formulate, design and demonstrate a novel energy efficient architecture for the actuation system of the future generation of electrified agricultural tractors using hydraulic functions. The focus will be on the actuation system for the tractor suspensions, steering, hitches and remotes, which is commonly based on energy-inefficient high pressure hydraulic technology, particularly when implements are powered through the hydraulic remotes.To accomplish this goal, the five-year research plan will include numerical modeling of the EH system, numerical optimization and experimental activities on a prototype machine (courtesy of Case New Holland Industrial, CNH).The plan can be structured according to following specific objectives:Objective 1 (O1). Architecture Formulation. In objective O1, the project will study basic layout solutions for the high-pressure hydraulic systems which can bring to a higher level of energy efficiency. Solutions suitable for the tractor electrification will also be considered. Among these solutions, also those suitable for electric hybridization will be considered, considering the possibility of storing energy in both the electric and the hydraulic forms. Within the activities of O1, the research will also develop parametric numerical models for each system architecture taken into consideration. These models will be capable of simulating the main energy flows within the system, in the mechanical, hydraulic and electric domains.Objective 2 (O2). System Design. The goal of O2 is to formulate an optimization procedure capable of determining the best size of each component for all the system architectures identified in O1. The definition of the optimization problem will require the formulation of measurable Objective Functions (OFs), representative of the energy consumption, but also of productivity and cost. In O2, duty cycles representative of the typical operation of an agricultural tractor will be determined, with the help of CNH. The optimization will also consider that the EH actuation system will need to meet certain function requirements, usually related to short actuations at extreme conditions. The main deliverable of O2 it to provide the best design for every candidate architecture, along with the expected performance parameters from simulation.Objective 3 (O3). Experimental tests. Objective O3 is to experimentally demonstrate the optimal architecture identified in O3 on a demo vehicle. The demo vehicle is a New Holland tractor available at Maha Labs (courtesy of CNH) and it will be used to gather the data for the model validation. If funding is available, Dr. Vacca's team will also implement a new EH hybrid architecture and test its functionality. The tests on the demo vehicle will support the modeling activity of O1, permitting the validation of the main model assumptions. More importantly, the tests will show the benefits of the proposed solution, mainly in terms of reduction of the energy consumption of the actuation system of the tractor.

Project Methods
The research objective of formulating and demonstrate a new energy efficient solutions for the hydraulic systems of agricultural tractors will be pursued with activities under three sub-objectives (O1, O2 and O3). The main deliverables of each objective will be accomplished through specific tasks, which are detailed in the Table 1 below. Milestones are shown in Table 2.All the research Tasks will be performed at the PD's lab at Purdue (Maha Fluid Power Research Center). The experimental activity will be performed with the help of an industry partner, CNH, which already made available to the Maha Fluid Power Research Center an agricultural tractor and the necessary data.Table 1 - List of task and main deliverable of the projectObjective 1 (O1): Architecture FormulationTaskBrief description - Deliverables1.1. Duty cycle definition- analysis of standard cycles present in literature: Nebraska tests, DLG Powermix, etc.- selection of an implement to consider as reference for the overall analysis tractor - implement. Possible choices: planter, sprayer.- identification of a reference utilization cycle for the high pressure hydraulic system on the basis of standard cycle but also on the conventional use of the tractor.1.2. Modeling of the state-of-the-art load sensing system- formulation of a simplified model for the standard load sensing system of the tractor. A lumped parameter model will be realized in Matlab-Simulink or Amesim for the supply pump, the EH remote valve, the steering priority valve, the rear hitch.- simulation of the system on the duty cycle identified in T1.1, inclusive of the implement actuation through the hydraulic remotes. Results in terms of internal energy flow and energy dissipation from the combustion engines to the end functions.1.3. energy efficient architecture 1: Electric Hybrid LS- formulation of the basic architecture based on advanced modifications of the standard hydraulic load sensing (LS) system. Modifications will include the use of variable margin strategies for varying the setting of the pump adjustment system. This will bring to a reduction of the throttling losses during the machine operation according to the duty cycle of T1.1.- formulation of a Matlab-Simulink or AMESim model for the system suitable for optimization purposes.- results from a preliminary sizing describing the energy flow within the system over the reference duty cycle of T1.1.1.4. energy efficient architecture 2: Electric-Hybrid systemThis activity will consider a solution that merges the hydraulic LS system with an electric system operating at high voltage connected to an electric generator-battery system. The generator will be connected to the thermal combustion engine. This activity will be performed in collaboration with Dr. Sudhoff's team at Purdue ECE.- formulation of the basic architecture: the thermal combustion engine is coupled with a high voltage electric generator-battery system which supplies individual and independent hydraulic actuators.- formulation of a Matlab-Simulink or AMESim model for the proposed system suitable for optimization purposes.- results from a preliminary sizing describing the energy flow within the system over the reference duty cycle of T1.1.Objective 2 (O2): System Design TaskDeliverables2.1. Optimization problem formulation- definition of measurable objective functions representative of: energy consumption from the energy entry point to the actuation system; system cost; reliability.- definition of the constrains: size limit of the EH components for the systems defined in T1.3 and T1.4.- definition of the operating requirements outside the reference drive cycle.2.2. Electric-Hybrid management- definition of the state-flow mode for both the hydraulic system and the electric system. Single actuator and simultaneous actuation (resistive and overrunning mode)- steady state and dynamic system analysis- energy management criteria and additional OF for best energy management.2.3. Design optimization- formulation of the optimization workflow. A multi-objective optimization problem based on T2.1 will be implemented in modeFrontier. The optimization problem including the OFs and the constrains of T2.1 will be implemented using the models developed in T1.3 and T1.4.- multi-objective optimization algorithm. A genetic algorithm coupled with response surface methodology will be used to perform this optimization.- optimization results will be generated for all the candidate architectures. The operating features of the candidate solutions will be compared in terms of the quantitative OFs definied in T2.1.- identification of the Pareto frontiers, and selection of the optimal solution for each candidate.Objective 3 (O3): Experiments TaskDeliverables3.1. Definition of the reference machines- the New Holland T380 tractor already available at Maha Labs and an implement will be used to support the experimental activity of the project. Component specifications, utilization cycles will be identified.In case the agricultural implement will not be available for unforeseen reasons, this research task will seek alternative solutions, either obtaining experimental data directly from an industry sponsor or from another implement available at Purdue.3.2. Instrumentation and tests- the reference system identified in 3.1 will be instrumented to permit a baseline measurement of the energy flow within the standard hydraulic technology system. These measurements will be performed by measuring the power at certain locations of the circuit, through the measurements of fluid pressure and flow rate.- stationary tests and dynamic tests on the duty cycles defined T1.1 will be reproduced to allow the validation of the lumped parameter model of T1.2 and T1.3.- an assessment of the model accuracy will be performed through a comparison between experimental data and simulation results.3.3 Proof of concept - set up- the solution identified in T2.3 will be implemented in the reference machine for experimentation. To reduce costs, the project will consider only a selected function, such as one hydraulic remote. In case of implementation of the electric hybrid system, the costs might be further reduced by not using an actual electric battery, but estimating the energy recuperations as energy dissipated though electric resistances.- the reference machine will be modified at Maha Labs, and properly equipped with a high voltage system to allow the implementation of the hydraulic or the electro-hydraulic solution considered for the testing.3.4. Proof of concept - tests- the prototype created in T3.3 will be used for a test campaign aimed at verifying the modeling approach used for this project.- the most important result of T3.4 is the energy consumption measurement on the reference drive cycles, which it is expected to be about 40% less than the consumption of the original machine tested in T3.1. This estimation comes from a preliminary study performed in 2019 that shows that the standard system can operate with low efficiency points below 15%.Table 1 - Project milestonesmilestoneDate of achievementDescription1Y1- month 12Identification of the reference off road set up and related specifications and significant duty-cycle2Y2- month 6Energy consumption of the baseline system. Execution of the baseline tests and assessment on model accuracy3Y2- month 12Energy efficient architecture 1: simulation model completion4Y3- month 6Energy efficient architecture 2: simulation model completion5Y3 - month 12Agricultural system equipped for testing an alternative solution on a simplified system (proof of concept tests)6Y4- month 12Design analysis for the optimal of energy efficient architectures7Y5- month 6Identification and sizing of the best architecture10Y5- month 12Completion of experimental tests. Final assessment on energy consumption vs baseline measurements

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:This research reaches the scientific community, with particular reference to industry OEMs, component manufacturers, and fluid power technical and academic community. The PD team is working onjournalpapers on presentations to conferences at both national and international level so that the results of the research are properly divulgated, thus increasing the awareness of the potentials of their proposed technology for agricultural tractors and off road vehicles. In future (not in the reporting period), publications to magazines such as Fluid Power, Diesel Progress, SAE magazine are also anticipated, with the aim of reaching a broader community of engineers and stakeholders and inform them about the possibility of utilizing more efficient systems that can lower fuel consumption and embrace electric technology. Lab tours and conference presentations were also given during the project period (before the start of the pandemic). The PD and co-PD haveengaged industry in their research: Case New Holland Industrial and Bosch Rexroth are actively supporting the research with in kind loan and component donation.Case New Holland is a major OEM in agricultural equipment while Bosch Rexroth a major supplier of hydraulic component and electro-hydraulic control systems.During the project periods lab tours were provided to additional companies including Trelleborg, Parker Hannifin, KYB, Ford, General Motors, Sumitomo). During the project period, Dr. Vacca gave invited talks to: IFPE2020, The International Fluid Power Exposition - Research Symposium, co-located with CONEXPO-CON/AGG2020, March 11, 2020, Las Vegas, NV, USA The 20th International Conference of Fluid Power and Mechatronic Control Engineering, November 8-10, 2019, Jiaxing, China Poclain Industries, December 13, 2019, Verberies, France. Center of Automotive Research (CAR), Ohio State University, February 4 2020 In all the above talks Dr. Vacca covered his vision for the future of the actuation technology for agricultural machines. Dr. Vacca teams also presented papers at professional society conferences and published research papers at international journals (see proper sections). Finally, Dr Vacca has reached the student audience during his classes in hydraulic control systems (ABE 435, ABE 591 and ME 597), where he educated the students towards more efficient hydraulic control technology. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?During the reporting period, training of professionals involved both graduate and undergraduate students at Purdue University. In particular, the PD exposed the students to the aspects of designing energy efficient hydraulic control systems suitable for off-road applications in his classes. These classes are ABE 435 (Hydraulic Control Systems) and ME 597 / ABE 591 (Design and Modeling of Fluid Power Systems). Several graduate students at the Maha Fluid Power Research Center (about 8) were exposed to the research tasks of this project, and involved in brainstorming activities, modeling effort and experimental tests. Two undergraduate students, one from Purdue ABE and one from Purdue ME were also involved. A post-doctoral person from ABE also assisted the supervising of the project actitvities. How have the results been disseminated to communities of interest?The results have been disseminated to the fluid power community through presentations at international conferences, invited talksas well as visits of component manufacturers to the Maha Fluid Power Research Center. While the list of technical papers is provided in a early section, the following list details the invited talks that Dr Vacca gave: - Invited Keynote Speech: "An Efficient Electro-Hydraulic Drive Technology for Off-Road Vehicles", The 20th International Conference of Fluid Power and Mechatronic Control Engineering, November 8-10, 2019, Jiaxing, China - Invited Seminar on "Approaches for improving hydraulic drive technologies", Poclain Industries, December 13, 2019, Verberies, France. - Invited Seminar on "Advancing Fluid Power Technology" at the Center of Automotive Research (CAR), Ohio State University, February 4 2020 - Invited Speaker at the IFPE2020, The International Fluid Power Exposition - Research Symposium, co-located with CONEXPO-CON/AGG. Presentation title "Individual Electro-Hydraulic Actuators for Off Road Machines", March 11, 2020, Las Vegas, NV, US In all these talks, Dr. Vacca included a part of the current USDA research project. Visitors to the lab included KYB, Case New Holland, Parker Hannifin, Bosch Rexroth, Poclain, Trelleborg. Unfortunately, this part of outreach, typically very successfull in the PD's lab (Maha Fluid Power Research Center), was heavily impacted by the pandemic. What do you plan to do during the next reporting period to accomplish the goals?The project will continue following the originally proposed timeline. Activities in the next project period will include all the project goals. For O1, the simulation model will be extended for the hydraulic system of the planter. Also, the proposed EH solution will be analyzed through simulation. For O2, an effort in creating an optimization workflow suitable to optimize the most promising solutions will be made, so that for each proposed solution, the best architecture will be found. The workflow will be implemented for the case of Multi Pressure Rail approach. For O3, baseline tests will be performed on the planter to validate the simulation model. First system modifications will be implemented in the tractor and in the planter to measure energy efficiency improvements.

Impacts
What was accomplished under these goals? During the first project period, accomplishments were made within all the three project objectives. The following paragraphs provide additional details: Objective 1 (O1). Architecture formulation. Accomplishments in O1 related to the tasks 1.1 (Duty cycle definition); 1.2 (Modeling of the state-of-the-art LS system); and 1.3 (EH hybrid architecture). The case of a reference tractor of power 380 hp was analyzed. Thanks to a New Holland tractor provided to Purdue by Case New Holland (CNH), it was possible to formulate a numerical model (implemented using the Amesim software) that reflects the nature of the high pressure system of a typical state-of-the-art tractor. The model was formulated with significant data provided by CNH and Bosch Rexroth, with the aim of achieving a good level of accuracy. The model validation was also performed based on the tests performed within O3, as it will be described later. A 16 row planter (Case Earlyriser) was selected as reference case for the hydraulic implement. This choice was made considering the power level of the implement (a planter is one of the most energy demand implements) and the US market (in US farmers make a wide use of large size planters). Objective 2 (O2). System Design. Progress in O2 involved tasks 2.1 (Definition of Objective Functions), 2.2 (Definition of contraints and energy requirements); 2.3 (Energy management system). In particular, somealternative architectures for both the tractor and the planter hydrualic control systems were formulated, These architectures aimed at minimizing the energy consumption of the overall hydraulic drive system, considering proper control strategies. Some of the architectures that have been formulated are based on minor modifications: in this group the most significant one is the advanced Electro-Hydraulic Load Sensing System. This architecture uses a electro-controlled supply pump with advanced control of the whole system according to a strategy derived from the theory of load sensing systems. Other architecture that were proposed are instead disruptive. A preliminary study on a system called Multi-Pressure Rail was performed within this research. Both systems accomplished the goal of increasing the energy efficiency during a simplified drive cycle that consider the planter in use. Objective 3 (O3). Experimental tests. During the reporting period, significant progress was made pertaining the tasks 3.1 (Reference machine definition); 3.2 (Reference machine intrumentation and tests) and 3.3 (Sub-system definition for proof of concept validation). As mentioned earlier in O1, two reference machines were selected as representative for this research: a New Holland Tractor (380 hp) and a 16 row planter. Units of similar size as the reference machines are very popular among US farms. The reference tractor was instrumented to perform baseline measurements on the consumption of the main hydraulic functions of the high pressure hydraulic system. A literature search permitted to define insufficient the current standards for testing the hydraulic systems for specific characterization of the energy losses. For this reason, Dr. Vacca's team, based also on feedback from CNH, formulated a specific test plan (this activity related also to task 1.1 of Objective O1).Measurements were performed to find the system efficiency of the fluid power transmission system. It was found that the efficiency on the hydraulic remotes, as significant users, can be as low as 25%, depending on the operating conditions. The model developed in O1 was also validated according to the measurements. A very good agreement was found. The model development and the validation activity allowed the team to publish already the results of their research (see publication section).

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Stump, P.M., Keller, N., Vacca, A., 2019, "Energy Management of Low-Pressure Systems Utilizing Pump-Unloading Valve and Accumulator," Energies, 12(23), 4423, DOI:10.3390/en12234423
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Tian, X., Vacca, A., Fiorati, S., Pintore, F., 2019, An Analysis of the Energy Consumption in the High-Pressure System of an Agricultural Tractor through Modeling and Experiment, 77th International Conference on Agricultural Engineering , Nov 8-9, 2019, Hannover, Germany, pp. 9-18.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Tian, X., Gomez, J.C., Vacca, A., Fiorati, S., Pintore, F., 2019, Analysis of Power Distribution in the Hydraulic Remote System of Agricultural Tractors Through Modelling and Simulations, ASME/Bath Symposium on Fluid Power and Motion Control, Oct. 7-9, 2019, Sarasota, FL, USA., DOI:10.1115/FPMC2019-1686
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Sciancalepore, A., Vacca, A., Pena, O., and Weber, S.T., 2019, Lumped Parameter Modeling of Counterbalance Valves Considering the Effect of Flow Forces., ASME/Bath Symposium on Fluid Power and Motion Control, Oct. 7-9, 2019, Sarasota, FL, USA., DOI:10.1115/FPMC2019-1650
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Manne, V.H.B., Vacca, A., Merrill, K., 2021, "A numerical method for evaluating the torque efficiency of hydraulic orbit motors considering deformation effects and frictional losses," Mechanical Systems and Signal Processing, 146, DOI:10.1016/j.ymssp.2020.107051