Urban and extra-urban hybrid vehicles: a technological review

Pollution derived from transportation systems is a worldwide, timelier issue than ever. The abatement actions of harmful substances in the air are on the agenda and they are necessary today to safeguard our welfare and that of the planet. Environmental pollution in large cities is approximately 20% due to the transportation system. In addition, private traffic contributes greatly to city pollution. Further, “vehicle operating life” is most often exceeded and vehicle emissions do not comply with European antipollution standards. It becomes mandatory to find a solution that respects the environment and, realize an appropriate transportation service to the customers. New technologies related to hybrid –electric engines are making great strides in reducing emissions, and the funds allocated by public authorities should be addressed. In addition, the use (implementation) of new technologies is also convenient from an economic point of view. In fact, by implementing the use of hybrid vehicles, fuel consumption can be reduced. The different hybrid configurations presented refer to such a series architecture, developed by the researchers and Research and Development groups. Regarding energy flows, different strategy logic or vehicle management units have been illustrated. Various configurations and vehicles were studied by simulating different driving cycles, both European approval and homologation and customer ones (typically municipal and university). The simulations have provided guidance on the optimal proposed configuration and information on the component to be used

Study of the Potential of Electrified Powertrains with Dual-Fuel Combustion to Achieve the 2025 Emissions Targets in Heavy-Duty Applications

[ES] El transporte de personas, así como de carga ha evolucionado y crecido tremendamente en los últimos años. El desarrollo tecnológico debió ser adaptado a las diferentes medidas gubernamentales en términos de control de emisiones contaminantes. Desde el acuerdo de Paris en 2015 para mantener el crecimiento de la temperatura global por debajo de 1.5oC, se han impuesto también límites para las emisiones de CO2 por parte de vehículos de carretera. Para el sector del transporte pesado, se han impuesto límites de flota de 15% para 2025 y 30% para 2030 de reducción del CO2 con respecto a 2019. Por lo tanto, esta doble restricción de muy bajos niveles de emisiones contaminantes, así como de gases de efecto invernadero hacen que el sector del transporte este ante un gran desafío tecnológico. En 2022, el transporte de carga tiene un 99% de vehículos propulsados a motor de combustión interna con Diesel como combustible y sin ningún tipo de ayuda eléctrica en el sistema de propulsión. Los límites de emisiones contaminantes como Euro 6 son alcanzados con complejos sistemas de postratamiento que además agregan el consumo de Urea. Trabajos previos en la bibliografía, así como sistemas prototipo han demostrado que es posible alcanzar los objetivos de emisiones contaminantes con métodos avanzados de control de la combustión y así disminuyendo la complejidad del post tratamiento en la salida de gases. Con mayor éxito, el concepto de Reactivity Controlled Combustion Ignition puede alcanzar valores por debajo de Euro 6 con eficiencia similar a la combustión de Diesel. Sin embargo, no soluciona los problemas de emisiones de CO2. Por otro lado, en vehículos de pasajeros fue demostrado con suceso la aplicación de motores eléctricos en el sistema de propulsión para mejorar la eficiencia global del vehículo. El caso extremo son los vehículos puramente electicos donde se alcanza eficiencias por arriba del 70% contra 35% de los vehículos no electrificados. Sin embargo, limitaciones de autonomía, tiempo de carga y la no clara reducción global de la contaminación debido a las emisiones de la energía de la red eléctrica y la contaminación de las baterías de ion-litio hacen que este sistema de propulsión este bajo discusión. Para los vehículos con algún grado de electrificación, las emisiones de gases contaminantes siguen siendo un problema como para el caso no electrificado. Por lo tanto, esta tesis doctoral aborda el problema de emisiones contaminantes, así como de CO2 combinado modos avanzados de combustión con sistemas de propulsión electrificado. La aplicación de estas tecnologías se centra en el sector del transporte de carretera pesado. En particular, un camión de 18 toneladas de carga máxima que originalmente en 2022 equipa un motor seis cilindros de 8 litros con combustión convencional Diesel. El presente trabajo utiliza herramientas experimentales como son medidas en banco motor, así como en carretera para alimentar y validar modelos numéricos de motor, sistema de postratamiento, así como de vehículo. Este último es el punto central del trabajo ya que permite abordar sistemas como el mild hybrid, full hybrid y plug-in hybrid. Calibración de motor experimental dedicada a sistemas de propulsión hibrido es presentada con combustibles sintéticos y/o para llegar a los límites de Euro 7.[CA] El transport de persones, així com de càrrega ha evolucionat i crescut tremendament en els últims anys. El desenvolupament tecnològic degué ser adaptat a les diferents mesures governamentals en termes de control d'emissions contaminants. Des de l'acord de Paris en 2015 per a mantindre el creixement de la temperatura global per davall de 1.5oC, s'han imposat també límits per a les emissions de CO¿ per part de vehicles de carretera. Per al sector del transport pesat, s'han imposat limites de flota de 15% per a 2025 i 30% per a 2030 de reducció del CO¿ respecte a 2019. Per tant, aquesta doble restricció de molt baixos nivells d'emissions contaminants, així com de gasos d'efecte d'hivernacle fan que el sector del transport aquest davant un gran desafiament tecnològic. En 2022, el transport de càrrega té un 99% de vehicles propulsats a motor de combustió interna amb Dièsel com a combustible i sense cap mena d'ajuda elèctrica en el sistema de propulsió. Els limites d'emissions contaminants com a Euro 6 són aconseguits amb complexos sistemes de posttractament que a més agreguen el consum d'Urea. Treballs previs en la bibliografia, així com sistemes prototip han demostrat que és possible aconseguir els objectius d'emissions contaminants amb mètodes avançats de control de la combustió i així disminuint la complexitat del post tractament en l'eixida de gasos. Amb major èxit, el concepte de Reactivity Controlled Combustion Ignition pot aconseguir valors per davall d'Euro 6 amb eficiència similar a la combustió de Dièsel. No obstant això, no soluciona els problemes d'emissions de CO¿. D'altra banda, en vehicles de passatgers va ser demostrat amb succés l'aplicació de motors elèctrics en el sistema de propulsió per a millorar l'eficiència global del vehicle. El cas extrem són els vehicles purament electicos on s'aconsegueix eficiències per dalt del 70% contra 35% dels vehicles no electrificats. No obstant això, limitacions d'autonomia, temps de càrrega i la no clara reducció global de la contaminació a causa de les emissions de l'energia de la xarxa elèctrica i la contaminació de les bateries d'ió-liti fan que aquest sistema de propulsió aquest baix discussió. Per als vehicles amb algun grau d'electrificació, les emissions de gasos contaminants continuen sent un problema com per al cas no electrificat. Per tant, aquesta tesi doctoral aborda el problema d'emissions contaminants, així com de CO¿ combinat maneres avançades de combustió amb sistemes de propulsió electrificat. L'aplicació d'aquestes tecnologies se centra en el sector del transport de carretera pesat. En particular, un camió de 18 tones de càrrega màxima que originalment en 2022 equipa un motor sis cilindres de 8 litres amb combustió convencional Dièsel. El present treball utilitza eines experimentals com són mesures en banc motor, així com en carretera per a alimentar i validar models numèrics de motor, sistema de posttractament, així com de vehicle. Est ultime és el punt central del treball ja que permet abordar sistemes com el mild hybrid, full *hybrid i plug-in hybrid. Calibratge de motor experimental dedicada a sistemes de propulsió hibride és presentada amb combustibles sintètics i/o per a arribar als límits d'Euro 7.[EN] The transport of people, as well as cargo, has evolved and grown tremendously over the recent years. Technological development had to be adapted to the different government measures for controlling polluting emissions. Since the Paris agreement in 2015 limits have also been imposed on the CO2 emissions from road vehicles to keep global temperature growth below 1.5oC. For the heavy transport sector, fleet limits of 15% for 2025 and 30% for 2030 CO2 reduction have been introduced with respect to the limits of 2019. Therefore, the current restriction of very low levels of polluting emissions, as well as greenhouse gases, makes the transport sector face a great technological challenge. In 2021, 99% of freight transport was powered by an internal combustion engine with Diesel as fuel and without any type of electrical assistance in the propulsion system. Moreover, polluting emission limits such as the Euro 6 are achieved with complex post-treatment systems that also add to the consumption of Urea. Previous research and prototype systems have shown that it is possible to achieve polluting emission targets with advanced combustion control methods, thus reducing the complexity of post-treatment in the exhaust gas. With greater success, the concept of Reactivity Controlled Combustion Ignition can reach values below the Euro 6 with similar efficiency to Diesel combustion. Unfortunately, it does not solve the CO2 emission problems. On the other hand, in passenger vehicles, the application of electric motors in the propulsion system has been shown to successfully improve the overall efficiency of the vehicle. The extreme case is the purely electric vehicles, where efficiencies above 70% are achieved against 35% of the non-electrified vehicles. However, limitations of vehicle range, charging time, payload reduction and an unclear overall reduction in greenhouse emissions bring this propulsion system under discussion. For vehicles with some degree of electrification, polluting gas emissions continue to be a problem as for the non-electrified case. Therefore, this doctoral Thesis addresses the problem of polluting emissions and CO2 combined with advanced modes of combustion with electrified propulsion systems. The application of these technologies focuses on the heavy road transport sector. In particular, an 18-ton maximum load truck that originally was equipped with an 8-liter six-cylinder engine with conventional Diesel combustion. The present work uses experimental tools such as measurements on the engine bench as well as on the road to feed and validate numerical models of the engine, after-treatment system, and the vehicle. The latter is the central point of the work since it allows addressing systems such as mild hybrid, full hybrid, and plug-in hybrid. Experimental engine calibration dedicated to hybrid propulsion systems is presented with synthetic fuels in order to reach the limits of the Euro 7.This Doctoral Thesis has been partially supported by the Universitat Politècnica de València through the predoctoral contract of the author (Subprograma 2), which is included within the framework of Programa de Apoyo para la Investigación y Desarrollo (PAID)Martínez Boggio, SD. (2022). Study of the Potential of Electrified Powertrains with Dual-Fuel Combustion to Achieve the 2025 Emissions Targets in Heavy-Duty Applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/18883

Concept modeling of energy efficiency for heavy-duty trucks with E-axle equipped trailer

Abstract. The purpose of this master’s thesis is to study potential of E-axle on a trailer to provide better maneuverability for heavy trucks, and the possibility of fuel savings and thus lower tailpipe emissions and operating costs of the vehicle. Three different truck combination types were studied, timber, tipper, and long-haul trucks. Real-life driving data and other information of the selected truck types are collected, and simulation model of the trucks are created with MATLAB. Models are validated by comparing the simulation results with the collected real life driving data. After validation, E-axle is added to the model and the potential of the E-axle is tested in the abovementioned use cases. The results indicate that even a relatively small battery of 20 kWh could yield substantial fuel savings in the range of 5–15 %, depending on the drive cycle. If battery has to be charged by driving operations, the net fuel saving ranges between -1–9 %. However, the used control logic for the E-axle in this study was very simple and better overall results can be expected with optimized system. Substantially increased hill climbing ability in highway speeds with E-axle was also demonstrated, even with downgraded engines. Findings provide good general information about the potential of E-axle in timber, tipper, and long-haul trucks.E-akselilla varustettujen raskaiden kuorma-autojen energiatehokkuuden konseptimallinnus. Tiivistelmä. Tämän diplomityön tarkoituksena on tutkia peräkärryyn asennettavan sähköisen akselin, eli E-akselin hyödyntämistä raskaiden ajoneuvojen liikkuvuuden parantamisessa, sekä kulutuksen ja siten päästöjen ja käyttökulujen pienentämisessä. Työn kohteena on kolme erilaista raskasta ajoneuvoyhdistelmää, puuauto, sora-auto, sekä kaukoliikenneauto, joista kerätään ajomittausdataa reaaliympäristössä. Kirjallisuudesta ja tutkimuksista hankittujen ajoneuvon tietojen, sekä kerätyn ajodatan perusteella luodaan ajoneuvoista simulointimallit MATLAB-ohjelmistolla, jossa mallin toimivuus validoidaan vertaamalla simuloinnissa saatuja tuloksia mitattuihin tuloksiin. Kun mallin toimivuus on varmistettu, lisätään malliin E-akseli ja verrataan ja arvioidaan E-akseli potentiaalia yllä mainituissa tapauksissa suhteessa tavalliseen autoon. Tulokset antavat olettaa, että jo suhteellisen pienellä akkukoolla kuten 20 kWh, voi olla mahdollista saavuttaa ajosyklistä riippuen 5–15 % polttoainesäästöjä. Mikäli akku joudutaan kuitenkin lataamaan ajamalla täyteen, niin nettopotentiaali voi vaihdella -1–9 % välillä. Täytyy kuitenkin muistaa, että tässä työssä käytetty ohjauslogiikka E-akselille on hyvin yksinkertainen ja siten voidaankin olettaa, että kunnollisella optimoidulla ohjauslogiikalla on mahdollista saavuttaa yleisesti ottaen parempia tuloksia. Myös mäennousukyvyssä huomattiin huomattava parannus Eakselilla varustetuissa ajoneuvoissa, myös tapauksissa, joissa moottorin kokoa oli pienennetty alkuperäisestä. Tulokset antavat yleispätevää tietoa E-akselin potentiaalista puuautossa, sora-autossa ja kaukoliikenne käytössä

Preliminary design of a fuel cell/battery hybrid powertrain for a heavy-duty yard truck for port logistics

Abstract The maritime transport and the port-logistic industry are key drivers of economic growth, although, they represent major contributors to climate change. In particular, maritime port facilities are typically located near cities or residential areas, thus having a significant direct environmental impact, in terms of air and water quality, as well as noise. The majority of the pollutant emissions in ports comes from cargo ships, and from all the related ports activities carried out by road vehicles. Therefore, a progressive reduction of the use of fossil fuels as a primary energy source for these vehicles and the promotion of cleaner powertrain alternatives is in order. The present study deals with the design of a new propulsion system for a heavy-duty vehicle for port applications. Specifically, this work aims at laying the foundations for the development of a benchmark industrial cargo–handling hydrogen-fueled vehicle to be used in real port operations. To this purpose, an on-field measurement campaign has been conducted to analyze the duty cycle of a commercial Diesel-engine yard truck currently used for terminal ports operations. The vehicle dynamics has been numerically modeled and validated against the acquired data, and the energy and power requirements for a plug-in fuel cell/battery hybrid powertrain replacing the Diesel powertrain on the same vehicle have been evaluated. Finally, a preliminary design of the new powertrain and a rule-based energy management strategy have been proposed, and the electric energy and hydrogen consumptions required to achieve the target driving range for roll-on and roll-off operations have been estimated. The results are promising, showing that the hybrid electric vehicle is capable of achieving excellent energy performances, by means of an efficient use of the fuel cell. An overall amount of roughly 12 kg of hydrogen is estimated to be required to accomplish the most demanding port operation, and meet the target of 6 h of continuous operation. Also, the vehicle powertrain ensures an adequate all-electric range, which is between approximately 1 and 2 h depending on the specific port operation. Potentially, the hydrogen-fueled yard truck is expected to lead to several benefits, such as local zero emissions, powertrain noise elimination, reduction of the vehicle maintenance costs, improving of the energy management, and increasing of operational efficiency

Impact of Intelligent Transportation Systems on Parallel Hybrid Electric Heavy Duty Vehicles

A hybrid electric vehicle uses multiple sources of energy that can be independently or all together used to propel the wheels. In the presented work, the vehicle propulsion controller (VPC) for a parallel heavy duty hybrid electric vehicle (HEV) model has been modified to manage the alternative power source in advance based on the forthcoming traffic information. The goal is to prepare the powertrain for the next power event by making more energy storage capacity to capture free energy via regenerative braking or store more energy for expected need. The method of preparation will be by managing the battery state of charge (SOC), which is a metal hydride battery for this study, to take advantage of opportunistic regeneration. Autonomie software was used to simulate parallel HEV models.;The results revealed that the proposed looking-ahead control strategy for a class 8 parallel hybrid heavy duty vehicle with an engine power of 410 kW had a substantial contribution in preparing the system for forthcoming power demand. The looking-ahead strategy employed in this study improved fuel economy from 0.5% on flat terrain to about 3% on mountain terrain. Moreover, a looking-ahead strategy can contribute significantly to maintaining adequate power for the vehicle on different terrain types. The engine power can be downsized (with looking-ahead strategy) therefore improving fuel economy up to 13% while maintaining adequate power over different terrain types. The battery energy capacity can be downsized (with looking-ahead strategy) by half while maintaining nearly the same benefits (i.e. fuel economy and adequate power) compared to the hybridization system without looking-ahead strategy. Since different routes types (i.e. flat, hilly and mountain terrains) were used to investigate the impact of the looking-ahead strategy on heavy duty parallel HEV, these results can generally be applied to many terrain and traffic situations

Toward Holistic Energy Management Strategies for Fuel Cell Hybrid Electric Vehicles in Heavy-Duty Applications

The increasing need to slow down climate change for environmental protection demands further advancements toward regenerative energy and sustainable mobility. While individual mobility applications are assumed to be satisfied with improving battery electric vehicles (BEVs), the growing sector of freight transport and heavy-duty applications requires alternative solutions to meet the requirements of long ranges and high payloads. Fuel cell hybrid electric vehicles (FCHEVs) emerge as a capable technology for high-energy applications. This technology comprises a fuel cell system (FCS) for energy supply combined with buffering energy storages, such as batteries or ultracapacitors. In this article, recent successful developments regarding FCHEVs in various heavy-duty applications are presented. Subsequently, an overview of the FCHEV drivetrain, its main components, and different topologies with an emphasis on heavy-duty trucks is given. In order to enable system layout optimization and energy management strategy (EMS) design, functionality and modeling approaches for the FCS, battery, ultracapacitor, and further relevant subsystems are briefly described. Afterward, common methodologies for EMS are structured, presenting a new taxonomy for dynamic optimization-based EMS from a control engineering perspective. Finally, the findings lead to a guideline toward holistic EMS, encouraging the co-optimization of system design, and EMS development for FCHEVs. For the EMS, we propose a layered model predictive control (MPC) approach, which takes velocity planning, the mitigation of degradation effects, and the auxiliaries into account simultaneously

CONCEPT EVALUATION AND DEVELOPMENT OF A NOVEL APPROACH FOR INTEGRATION OF TURBOGENERATION, ELECTRIFICATION AND SUPERCHARGING ON HEAVY DUTY ENGINES

While many technologies such as electrically assisted turbocharging, exhaust energy recovery and mild hybridization have already proven to significantly increase heavy-duty engine efficiency, the key challenge to their widespread adoption has been their cost effectiveness and packaging. This research specifically addresses these challenges through evaluation and development of a novel technology concept termed as the Integrated Turbogeneration, Electrification and Supercharging (ITES) system. The concept integrates a secondary compressor, a turbocompound/expander turbine and an electric motor through a planetary gearset into the engine cranktrain. The approach enables a reduced system cost and space-claim, while maximizing the efficiency benefits of independent technologies. First, an assessment of design alternatives for integration of the identified key engine technologies on a heavy-duty engine was conducted. Once the ITES concept was down selected, the research then focused on model-based optimization and evaluation of the ITES system for a downsized medium heavy-duty diesel engine applied in Class 6-7 urban vocational application. As an outcome of the evaluation, a 1D simulation based sizing methodology of ITES system components was proposed. Furthermore, a novel control strategy for the ITES system was developed that combines equivalent consumption based steady-state offline optimization with functional controls for transient operation and smooth mode switching. The offline optimization method was also extended to evaluate the potential of ITES system in increasing aftertreatment temperature, which is critical for meeting future ultra-low NOx emission standards. Lastly, using 1D simulation of validated models, the efficiency benefit of ITES system on engine certification and vehicle drive cycles was predicted for the Class 6-7 urban vocational application. In comparison to baseline engine, the downsized engine with ITES system predicted an 8.5% reduction in engine fuel consumption on HDFTP cycle, 19.3% increase in fuel economy on ARB Transient cycle and 23.7% increase in fuel economy on a real-world drive cycle

Energy assessment of an electrically heated catalyst in a hybrid RCCI truck

[EN] Reactivity controlled compression ignition (RCCI) combustion showed great advantages in terms of engine-out NOx and soot emissions reduction. However, HC and CO emissions are larger than with conventional diesel combustion. Commercial oxidation catalysts can deal with the amount of HC and CO generated during the RCCI combustion only at warm conditions, thus limiting the implementation of this concept in conventional vehicles and in RCCI hybrid applications due to the large engine stop periods. This work aims to study the behaviour of an electrically heated catalyst used in a hybrid medium-duty truck operating with diesel-gasoline RCCI combustion. A parallel P2 full hybrid medium-duty truck is studied in transient conditions by means of numerical simulations validated with experimental data. The results are compared to those from the commercial diesel non-hybrid truck and the RCCI non-hybrid concept with a commercial oxidation catalyst. The results show that the fuel consumption increases about 2 % in combined cycles and 5 % in urban cases with respect to the non-hybrid RCCI case with a commercial oxidation catalyst. Finally, it was found that the RCCI hybrid concept with the electrically heated catalyst allows to achieve the EUVI targets for all the pollutant emissions with CO2 levels of 15 %. (C) 2021 The Authors. Published by Elsevier Ltd.The authors thanks ARAMCO Overseas Company and VOLVO Group Trucks Technology for supporting this research. The authors also acknowledge the Conselleria de Innovacion, Universidades, Ciencia y Sociedad Digital de la Generalitat Valenciana for partially supporting this research through grant number GV/2020/017.García Martínez, A.; Monsalve-Serrano, J.; Lago Sari, R.; Martínez-Boggio, SD. (2022). Energy assessment of an electrically heated catalyst in a hybrid RCCI truck. Energy. 238:1-19. https://doi.org/10.1016/j.energy.2021.12168111923