Comparison of energy consumption and costs of different HEVs and PHEVs in European and American context

This paper will analyse on the one hand the potential of Plug in Hybrid electric Vehicles to significantly reduce fuel consumption and displace it torward various primary energies thanks to the electricity sector. On the other hand the total cost of ownership of two different PHEV architectures will be compared to a conventional cehicle and a HEV without external charging

Development and Validation of a Control Strategy for a Parallel Hybrid (Diesel-Electric) Powertrain

The rise in overall powertrain complexity and the stringent performance requirements of a hybrid electric vehicle (HEV) have elevated the role of its powertrain control strategy to considerable importance. Iterative modeling and simulation form an integral part of the control strategy design process and industry engineers rely on proprietary ?legacy? models to rapidly develop and implement control strategies. However, others must initiate new algorithms and models in order to develop production-capable control systems. This thesis demonstrates the development and validation of a charge-sustaining control algorithm for a through-the-road (TTR) parallel hybrid (diesel-electric) powertrain. Some unique approaches used in powertrain-level control of other commercial and prototype vehicles have been adopted to incrementally develop this control strategy. The real-time performance of the control strategy has been analyzed through on-road and chassis dynamometer tests over several standard drive cycles. Substantial quantitative improvements in the overall HEV performance over the stock configuration, including better acceleration and fuel-economy have been achieved

Development of a Variable Roller Pump and Evaluation of its Power Saving Potential as a Charge Pump in Hydrostatic Drivetrains

Predložená doktorandská dizertačná práca (ďalej len práca) sa zaoberá rozsiahlou analýzou valčekového hydrogenerátora s premenlivým geometrickým objemom a predikciou výkonových úspor dosiahnutých aplikáciou navrhnutého valčekového hydrogenerátora s premenlivým geometrickým objemom v hydrostatickom pohone vybraných mobilných pracovných strojov. Teoretický rozbor princípov fungovania valčekového hydrogenerátora a teória jednorozmerného simulačného modelu sú popísané v prvej časti práce. Na základe odvodenej teórie je vytvorený simulačný model, ktorý je vhodný na predikciu priebehu tlaku v komorách valčekového hydrogenerátora, síl pôsobiacich na valček a na predikciu vnútorných únikov vzniknutých skratovaním rozvodovej dosky, ktoré majú priamy vplyv na objemovú účinnosť valčekového hydrogenerátora. Simulačný model bol úspešne použitý pre optimalizáciu rozvodových dosiek valčekového hydrogenerátora a vhodnosť simulačného modelu potvrdili následné merania Práca obsahuje aj analýzu síl pôsobiacich na vodiaci prstenec, ktorej výsledky boli taktiež potvrdené meraním. Analýza týchto síl môže vylepšiť v konečnom dôsledku parametre budúcich tlakových regulácii. Práca ďalej obsahuje základné porovnanie použitých tlakových regulácii. Všetky uskutočnené merania potvrdili, že valčekový hydrogenerátor s premenlivým geometrickým objemom s testovanými tlakovými reguláciami je schopný úspešne pracovať v hydrostatickej prevodovke. Druhá časť práce analyzuje potenciál výkonových úspor valčekového hydrogenerátora s premenlivým geometrickým objemom pre dve mobilné aplikácie - teleskopický nakladač s hmotnosťou 9 ton a kombajn s hmotnosťou 20 ton. Analýza vyžaduje jednorozmerný simulačný model hydrostatického pohonu s teplotnou predikciou hydrostatickej prevodovky. Dva rozdielne koncepty variabilného doplňovacieho systému hydrostatickej prevodovky sú porovnané so štandardným doplňovacím systémom pre pracovný a transportný režim oboch vybraných typov vozidiel. Simulácia pohonu vozidla s valčekovým hydrogenerátorom s premenlivým geometrickým objemom vo funkcii doplňovacieho hydrogenerátora a obtokovou clonou potvrdili vyššie úspory iba v prípadoch, kedy rýchlosť doplňovacieho hydrogenerátora bola výrazne vyššia a prietok cez obtokovú clonu do skrine hlavného hydrogenerátora zabezpečil dostatočné chladenie. Najvyššie výkonové úspory boli dosiahnuté s premenlivým preplachovacím systémom, ktorého prietok sa menil podľa požiadaviek hydrostatickej prevodovky. Záver druhej časti práce sa zaoberá metodikou dimenzovania veľkosti doplňovacieho hydrogenerátora.Presented doctoral thesis deals with an extensive hydraulic variable roller pump analysis and the power saving prediction of hydrostatic drivetrains in the mobile machines achieved with a variable roller charge pump implementation. At the first part of the work, the roller pump functionality was described and the theory of a 1-D simulation model was developed. Based on this developed simulation model is suitable for pressure profile prediction, roller force prediction and cross port leakage prediction which has a direct impact on the total volumetric efficiency. The simulation model was successfully used as a tool for optimization of the port plates, which was confirmed by measurements. The first part of the work includes the pump control force analysis validated by measurements and also the basic pressure compensator controls comparison. Developed control force prediction could help to improve the control performance. The measurements confirmed that the variable roller charge pump is able to successfully work in transmissions with measured types of the control. The second part of the work analyzed the power saving potential of a variable charge pump for two selected typical mobile applications: telehandler (9 ton) and combine harvester (20 ton). This part required a 1-D drivetrain simulation model together with thermal behaviour of the hydrostatic transmission. Two different modifications of the charging systems were compared with the conventional charging system in simulations performed for the working and transporting mode. The drivetrain simulation of the variable roller charge pump with a bypass orifice confirms higher power savings only in cases when the pump speed was significantly higher than normal speeds and a relatively constant flushing flow through the bypass orifice to the pump case still ensures suitable cooling. The highest power savings were achieved with variable flushing flows, where the demand for charging flow was adjusted according to the hydrostatic transmission cooling requirements. At the end of the second part, this thesis deals with a variable charge pump sizing.

Energy Efficient Longitudinal Control

Vehicles are contributing to global and local environmental problems as a result of fossil fuels. A majority of the combustion engine population is driven by fossil fuels and electrified vehicles are also to a large extent dependent on electricity production from fossil fuels. Emission legislation and standardized test methods have lead the development of technology for the automotive industry. Increased efficiency, improved combustion control and aftertreatment systems have created cleaner and more fuel efficient drivetrains. Authorities and publications have highlighted an increased gap between in-use and certified vehicle consumption and emissions because of the test-cycles current design. In order to address these differences authorities have conducted changes within the test methods from 2017 and forward and a new test-cycle WLTP is introduced including real-driving-emission test procedures. Decreasing the gap of real driving emissions and consumption can also be improved outside the legislative test-cycles using forward looking sensors, map data and statistical models.The work considers controlling the drivetrain actuators more efficiently in a vehicle with predictive information. For this, dynamic programming is used to optimize engine speed trajectories during depletion mode for a series hybrid drivetrain. The result shows that choice of state and control signals has a direct impact on the engine speed trajectory and thereby the fuel consumption. Up to 21 % lower fuel consumption could be achieved for a series hybrid drivetrain compared to a rule based engine speed demand controller (along the best efficiency line) for the drivecycle analyzed. For a parallel hybrid drivetrain a DP method was compared to a heuristic strategy in order to determine the optimal discharge rate of the battery. In the simulation study done the DP method provided the best fuel consumption results. During evaluation of the physical tests the pre-optimized DP parameter set performed worse than the heuristic strategy. In the rig tests a fuel consumption reduction of 8 % was measured with the heuristic method, compared to a non predictive controller strategy. The DP algorithm provided 4 % reduction of fuel compared to a non predictive controller.The work has also considered different modeling methods of a high voltage battery from recorded fleet data. One individual vehicle recorded battery pack current and voltage for one year. The recorded data was used to identify battery parameters for electric equivalent circuits. The measured current was used to calculate a reference voltage from the circuit equivalent parameters that was compared to the measured voltage. The best result was obtained for a single RC circuit model which obtained the highest average goodness of fit in voltage for the entire training data set

Optimal power management of hybrid electric vehicles through drivetrain analysis

The inefficient performance of gasoline-engine based vehicles along with high emissions and fuel consumption can be improved through utilization of hybrid electric vehicles (HEVs). The multiple power and energy sources in the hybrid drivetrain can be well managed through an appropriate control strategy that supervises the power distribution. While doing so, the control strategy needs to operate every component optimally in addition to overseeing controlled charge-discharge of battery to obtain efficient energy usage. In this thesis an algorithm has been developed for efficient power division among the various components of a series-parallel (S-P) drivetrain. It has been designed to manage the power flow with the least possible losses while keeping fuel economy at an optimum level and maintaining battery state-of-charge (SOC) in a pre-defined range. The importance of optimizing both engine and motor has been discussed. Analysis has also been presented to show possible benefit of using diesel instead of gasoline engine for hybrid vehicles

The novel application of optimization and charge blended energy management control for component downsizing within a plug-in hybrid electric vehicle

The adoption of Plug-in Hybrid Electric Vehicles (PHEVs) is widely seen as an interim solution for the decarbonization of the transport sector. Within a PHEV, determining the required energy storage capacity of the battery remains one of the primary concerns for vehicle manufacturers and system integrators. This fact is particularly pertinent since the battery constitutes the largest contributor to vehicle mass. Furthermore, the financial cost associated with the procurement, design and integration of battery systems is often cited as one of the main barriers to vehicle commercialization. The ability to integrate the optimization of the energy management control system with the sizing of key PHEV powertrain components presents a significant area of research. Contained within this paper is an optimization study in which a charge blended strategy is used to facilitate the downsizing of the electrical machine, the internal combustion engine and the high voltage battery. An improved Equivalent Consumption Method has been used to manage the optimal power split within the powertrain as the PHEV traverses a range of different drivecycles. For a target CO2 value and drivecycle, results show that this approach can yield significant downsizing opportunities, with cost reductions on the order of 2%–9% being realizable

Wind turbine drivetrains:State-of-the-art technologies and future development trends

This paper presents the state-of-the-art technologies and development trends of wind turbine drivetrains – the system that converts kinetic energy of the wind to electrical energy – in different stages of their life cycle: design, manufacturing, installation, operation, lifetime extension, decommissioning and recycling. Offshore development and digitalization are also a focal point in this study. Drivetrain in this context includes the whole power conversion system: main bearing, shafts, gearbox, generator and power converter. The main aim of this article is to review the drivetrain technology development as well as to identify future challenges and research gaps. The main challenges in drivetrain research identified in this paper include drivetrain dynamic responses in large or floating turbines, aerodynamic and farm control effects, use of rare-earth material in generators, improving reliability through prognostics, and use of advances in digitalization. These challenges illustrate the multidisciplinary aspect of wind turbine drivetrains, which emphasizes the need for more interdisciplinary research and collaboration

Design and Control of a Multiphase Interleaving DC-DC Converter with Loss Optimizing Operating Strategies for Electric Vehicle

The drivetrain components of commercial electric vehicles include the battery pack, inverter, and electric machine. However, in such a drivetrain configuration, the inverter input voltage (DC-Link voltage) is equal to the battery voltage, which presents some drawbacks. Firstly, different values are required to achieve the optimum voltage level during the battery stack and electric machine design process. Secondly, the battery state of charge negatively impacts the electric machine operating area. Additionally, as it will be demonstrated in this work, reducing the DC-Link voltage lowers inverter power losses. In operating points where the necessary machine voltage is lower than the battery voltage rated value, a fixed DC-Link voltage equal to the battery voltage results in additional inverter losses. The focus of this work is on the design and analysis of a battery electric vehicle drivetrain using an additional DC-DC converter extension in it. Accordingly, the main objective is to investigate the energy efficiency benefits of shifting the operating points of the drivetrain components by placing a DC-DC converter between the battery and the inverter-fed machine. For this purpose, a multiphase interleaving converter is selected, and through comprehensive modeling of the drivetrain, the appropriate control system is designed and evaluated on the one hand, and loss optimizing operating strategies are developed on the other hand to take the most advantage of the integration of a DC-DC converter into the drivetrain