Alternative Drivetrain Research Articles

The emission of off-road vehicles and their reduction options

Abstract The reduction of harmful emissions is a popular topic in both scientific and public circles. Contrary to popular belief, emissions from transport are only a small part of global emissions. As shown in the figure, the average of the EU 27 countries attributes only 15% of emissions from transport. From common perspective, vehicles with internal combustion, including diesel engines, will soon be replaced by alternative drivetrains. However at least at the commercial and off-road transportation, the diesel technology it is not so easy, and also the environmental reasons are questionable. Although the local emissions of electric vehicles are zero, their global emissions are, according to some research, more significant than their counterparts with internal combustion engines. The total electricity produced in the world in 2016 was about 25 PWh, two-thirds of which came from fossil energy carriers, which seriously damages the ecosystem, so it cannot be labelled as green energy.

Success Factors of Adopting Hydrogen Fuel Cars in Central Europe – An Analysis Regarding the Criteria of Purchasing Alternative Drivetrains

Current mobility is undergoing a transformation encompassing a multi-tude of elements, namely because of societal and governmental initia-tives to make car-based personal transportation more sustainable and less resource-intensive. Drivetrain technology, the main component in automotive vehicles, however, alters fuel supply, infrastructure, supply chains, and even convenience aspects, which were previously taken for granted, causing new challenges. On the basis of the literature around the subject of effective customer acceptance of battery-powered cars and the technological aspects of hydrogen fuel cell vehi-cles, a questionnaire consisting of eleven questions was developed. Items cover overall ecological, economic, and convenience-related concerns to evaluate current consumer expectations and knowledge level about hydrogen transportation. Results reveal, that in hydrogen mobility needs to fulfil the criteria of price stable hydrogen, made pos-sible by domestic and thereby resilient supply chains, actually allowing to provide an environmentally friendly individual transport in the first place. Additionally, existing benefits of current gen vehicles (combus-tion and battery electric vehicles), namely the aspect of safety and re-duced noise emissions are well appreciated by consumers. These re-sults outline what governmental institutions of all levels must prioritize in their adapted policymaking to further decarbonize transportation and openly promote hydrogen as an innovative fuel in Central Europe.

Flexible assembly layouts in smart manufacturing: An impact assessment for the automotive industry

Currently, automotive manufacturers take the concept of flexible manufacturing to an unprecedented level, considering the deployment of flexible assembly layouts (also known as matrix production systems) in which automated guided vehicles transport bodyworks on individual routes between assembly stations. To this end, a methodological framework that allows the assessment of the impact of technology choice decisions between traditional assembly lines and flexible assembly layouts as well as the impact of different flexibility levers and configurations is necessary for optimal decision support. We provide such a framework based on analytical insights and a chance-constrained problem formulation. We further show how this problem formulation can be solved optimally using a tailored branch-and-price algorithm. Our results quantify the impact of different flexibility configurations in flexible assembly layouts. We show that flexibility enables a simultaneous improvement in worker utilization and work in progress, resolving a classic trade-off in manufacturing systems. Moreover, we find that worker utilization and output are up to 30% higher in flexible assembly layouts compared with line assembly layouts. Further, flexible assembly layouts prove to be especially beneficial during the ramp-up of vehicles with alternative drivetrain technologies, such as the current transition to electric vehicles.

Domestic value added as an indicator for sustainability assessment: a case study on alternative drivetrains in the passenger car sector

To strengthen the economic pillar in sustainability assessment, the indicator ‘domestic value added’ is introduced. It aims at comparing established and less developed technologies regarding their prospective value added in a country. This is done by classifying a technology’s value added to the developed categories: domestic, potential domestic and non-domestic. Within this paper, two methods for assessing this indicator are introduced focussing on their applicability in a sustainability assessment context. Both methods are tested on a case study comparing two alternative drivetrain technologies for the passenger car sector (battery and fuel cell electric vehicle) to the conventionally used internal combustion engine. The first method is life cycle cost-based whereas the second is based on Input Output analysis. If a life cycle cost assessment is already available for the technology under assessment, the easier to implement life cycle cost-based approach is recommended, as the results are similar to the more complex Input Output-based approach. From the ‘domestic value added’ perspective, the battery electric vehicle is already more advantageous than the conventional internal combustion engine over the lifecycle. Fuel cell electric vehicles have the highest potential to increase their ‘domestic value added’ share in the future. This paper broadens the economic pillar in sustainability assessment by introducing a new indicator ‘domestic value added’ and giving practical information on how to prospectively assess it for existing and less developed technologies or innovations.Graphical abstract

How to integrate real-world user behavior into models of the market diffusion of alternative fuels in passenger cars - An in-depth comparison of three models for Germany

The future market diffusion of alternative fuels in the passenger car sector is of great interest to both carmakers and policymakers in order to decrease CO2 emissions. The decision to buy a car is not totally objective and only partly based on cost. For this reason, those modeling the future market evolution of cars powered by alternative fuels try to include behavioral and non-cost related aspects. This paper analyzes the integration of user behavior into market diffusion models and compares three models that include this aspect. The comparison comprises three parts: first, it compares the modeling approaches, then uses a harmonized data set to model the future market diffusion of alternative fuel vehicles, with and without behavioral aspects. The most important aspects of user behavior included in the models are the use of charging infrastructure, the limited model availability, the consideration of range anxiety as a hampering factor or the willingness-to-pay-more for alternative drivetrains as a supporting factor, as well as a distinction of users' driving distances. User behavior is considered in various ways, but always has a limiting effect on electric vehicle market diffusion. While a model that distinguishes individual users and driving distances stresses the high relevance of this aspect, it is considered less important in models with a more aggregated inclusion of user behavior based on logit functions.

Objective Rating of the Launch Behavior of Conventional, Hybrid and Electric Vehicles

The calibration of conventional, hybrid and electric drivetrains is an important process during the development phase of any vehicle. Therefore, to optimize the comfort and dynamic behavior (known as driveability), many test drives are performed by experienced drivers during different driving maneuvers, e.g., launch, re-launch or gear shift. However, the process can be kept more consistent and independent of human-based deviations by using objective ratings. This study first introduces an objective rating system developed for the launch behavior of conventional vehicles with automatic transmission, dual-clutch transmission, and alternative drivetrains. Then, the launch behavior, namely comfort and dynamic quality, is compared between two conventional vehicles, a plug-in hybrid electric vehicle and a battery electric vehicle. Results show the benefits of pure electric drivetrains due to the lack of launch and shifting elements, as well as the usage of a highly dynamic electric motor. While the plug-in hybrid achieves a 10% higher overall rating compared to the baseline conventional vehicle, the pure electric vehicle even achieves a 21% higher overall rating. The results also highlight the optimization potential of battery electric vehicles regarding their comfort and dynamic characteristics. The transitions and the gradient of the acceleration build-up have a major influence on the launch quality.

Transitioning to clean energy transportation services: Life-cycle cost analysis for vehicle fleets

Comprehensive global decarbonization requires that transportation services cease to rely on fossil fuels for power generation. This paper develops a generic, time-driven life-cycle cost model for mobility services to address two closely related questions central to the emergence of clean energy transportation services: (i) the utilization rates (hours of operation) that determine how alternative drivetrains rank in terms of their cost, and (ii) the cost-efficient share of clean energy drivetrains in a vehicle fleet composed of competing drivetrains. The model compares alternative drivetrains with different environmental and economic characteristics in terms of their life-cycle cost for any given duty cycle. The critical utilization rate that equates any two drivetrains in terms of their life-cycle cost is shown to also provide the optimization criterion for the efficient mix of vehicles in a fleet. This model framework is then calibrated in the context of urban transit buses, on the basis of actual cost- and operational data for an entire bus fleet. In particular, our analysis highlights how the economic comparison between diesel and battery-electric transit buses depends on the specifics of the duty cycle (route) to be served. While electric buses entail substantially higher upfront acquisition costs, the results show that they obtain lower life-cycle costs once utilization rates exceed only 20% of the annual hours, even for less favorable duty cycles. At the same time, the current economics of the service profile examined in our study still calls for the overall fleet to have a one-third share of diesel drivetrains.

Cost-Effcient Transition to Clean Energy Transportation Services

Comprehensive global decarbonization requires transportation services cease to rely on fossil fuels for power generation. This paper develops a generic, time-driven life-cycle cost model for mobility services to address two closely related questions central to the emergence of clean energy transportation services: (i) the utilization rates (hours of operation) that determine how alternative drivetrains can be ranked in terms of their cost, and (ii) the cost-efficient share of clean energy drivetrains in a vehicle fleet composed of competing drivetrains. The model ranks alternative drivetrains with different environmental and economic characteristics in terms of their life-cycle cost for any given duty cycle. The critical utilization rate that equates any two drivetrains in terms of their life-cycle cost is shown to also provide the optimization criterion for the efficient mix of vehicles in a fleet. This model framework is then calibrated in the context of urban transit buses, on the basis of actual cost- and operational data for an entire bus fleet. In particular, our analysis highlights how the economic comparison between diesel and battery-electric transit buses depends on the specifics of the duty cycle (route) to be served. While electric buses entail substantially higher upfront acquisition costs, the results show that they obtain lower life-cycle costs once utilization rates exceed only 20% of the annual hours, even for less favorable duty cycles. At the same time, the current economics of the service profile examined in our study still calls for the overall fleet to have a one-third share of diesel drivetrains.

Life cycle environmental and cost comparison of current and future passenger cars under different energy scenarios

In this analysis, life cycle environmental burdens and total costs of ownership (TCO) of current (2017) and future (2040) passenger cars with different powertrain configurations are compared. For all vehicle configurations, probability distributions are defined for all performance parameters. Using these, a Monte Carlo based global sensitivity analysis is performed to determine the input parameters that contribute most to overall variability of results. To capture the systematic effects of the energy transition, future electricity scenarios are deeply integrated into the ecoinvent life cycle assessment background database. With this integration, not only the way how future electric vehicles are charged is captured, but also how future vehicles and batteries are produced. If electricity has a life cycle carbon content similar to or better than a modern natural gas combined cycle powerplant, full powertrain electrification makes sense from a climate point of view, and in many cases also provides reductions in TCO. In general, vehicles with smaller batteries and longer lifetime distances have the best cost and climate performance. If a very large driving range is required or clean electricity is not available, hybrid powertrain and compressed natural gas vehicles are good options in terms of both costs and climate change impacts. Alternative powertrains containing large batteries or fuel cells are the most sensitive to changes in the future electricity system as their life cycles are more electricity intensive. The benefits of these alternative drivetrains are strongly linked to the success of the energy transition: the more the electricity sector is decarbonized, the greater the benefit of electrifying passenger vehicles.

A Review of Life Cycle Assessment Studies of Electric Vehicles with a Focus on Resource Use

Changes in the mobility patterns have evoked concerns about the future availability of certain raw materials necessary to produce alternative drivetrains and related batteries. The goal of this article is to determine if resource use aspects are adequately reflected within life cycle assessment (LCA) case studies of electric vehicles (EV). Overall, 103 LCA studies on electric vehicles from 2009 to 2018 are evaluated regarding their objective, scope, considered impact categories, and assessment methods—with a focus on resource depletion and criticality. The performed analysis shows that only 24 out of 76 EV LCA and 10 out of 27 battery LCA address the issue of resources. The majority of the studies apply one of these methods: CML-IA, ReCiPe, or Eco-Indicator 99. In most studies, EV show higher results for mineral and metal resource depletion than internal combustion engine vehicles (ICEV). The batteries analysis shows that lithium, manganese, copper, and nickel are responsible for the highest burdens. Only few publications approach resource criticality. Although this topic is a serious concern for future mobility, it is currently not comprehensively and consistently considered within LCA studies of electric vehicles. Criticality should be included in the analyses in order to derive results on the potential risks associated with certain resources.

A probabilistic fleet analysis for energy consumption, life cycle cost and greenhouse gas emissions modelling of bus technologies

Introducing alternative bus fleet technologies requires investigation into life cycle impacts, risks and benefits. Previous modelling approaches comparatively assess individual vehicle energy demands and life cycle impacts, assuming alternative technologies can fulfil identical life cycle functions to a diesel baseline. This assumption neglects the influence that service frequency, capacity and range limitations have on daily operations and fleet and infrastructure sizing. The goal of this study was to develop a framework to investigate bus fleet operation in terms of the risk and uncertainty of an alternative drivetrain technology’s ability to mitigate life cycle costs and greenhouse gas emissions. Probabilistic simulation enabled risk and uncertainty quantification of diesel, micro-hybrid, mild-hybrid and battery-electric fleet scenarios for a UK case study. The fleet analysis approach revealed decreased potential to reduce life cycle costs and greenhouse gas emissions from battery-electric buses. Compared to a baseline single-deck diesel fleet at low risk levels, the micro-hybrid double-deck fleet delivers the largest life cycle cost savings (18.7%). The largest life cycle greenhouse gas emissions savings come from the mild-hybrid lithium-titanate single-deck fleet (20.8%). Double-deck micro and mild hybrid fleets are the most effective at saving both life cycle costs and greenhouse gas emissions. The modelling approach adds a novel probabilistic capability for making comparative fleet-wide assertions, supporting the decision-making process for implementing new sustainable fleet technologies.

Cost-Efficient Transition to Clean Energy Transportation Services

Comprehensive global decarbonization will require that transportation services cease to rely on fossil fuels. Here we develop a generic life-cycle cost model to address two closely related questions central to the emergence of sustainable transportation: (i) the utilization rates (hours of operation) that rank-order alternative drivetrains in terms of their cost, and (ii) the cost-efficient share of clean energy drivetrains in a vehicle fleet of competing drivetrains. Calibrating our model framework in the context of urban transit buses, we examine how the comparison between diesel and battery-electric buses varies with the specifics of the duty cycle (route). We find that even for less favorable duty cycles, battery-electric buses will entail lower life-cycle costs once utilization rates exceed 20% of the annual hours. Yet, the current economics of that particular application still calls for a one-third share of diesel drivetrains in a cost-efficient fleet.

Perspectives of Powder Metallurgy in the 2020s

In the automotive industry there is a clear trend towards alternative drivetrain systems, away from the classical internal combustion – gasoline or diesel - engines. This poses a challenge to the traditional markets of powder metallurgy, the ferrous precision parts for automotive engines and transmissions which form the major tonnage of today’s powder metallurgy [1, 2], but also the hardmetal tools for machining automotive components from stock material or for finishing [3]. To counter these trends, powder metallurgy can rely on its high flexibility regarding materials, geometries, processing and properties and finally applications, which enables PM to adapt itself to changing requirements in a changing industrial environment [4]. In the present article, examples are given both for PM precision parts and hardmetals but also functional materials such as soft magnetic composites. It is shown that the potential of ferrous PM parts regarding mechanical performance is still higher than currently used, high and graded density being attractive ways [5]. Also the use of advanced alloying systems offers economical and technical advantages and should enable PM to enter non-automotive markets for precision parts. In the hardmetal branch, non-automotive applications, e.g. in construction and mining, should be considered while from the material viewpoint replacing tungsten and in particular Co as binder metal are intensely studied. PM functional materials such as Fe-Ni, Fe-Co and in particular soft magnetic composites will find markets in electrical drive systems [6], enabling new designs for electric motors. On the other end of the spectrum, superhard rare earth magnets are regularly produced by the powder route. Finally, the multitude of additive manufacturing techniques offers chances for powder metallurgy since most of these processes start from metal powders [7]. In addition to the well known laser and electron beam based “direct” AM systems, also indirect, binder-based, variants are attractive, avoiding many problems encountered with the direct systems and enabling transfer of knowhow accumulated in metal injection moulding. In general, future will show how many other technologies and products has to offer in addition to the classical press-and-sinter routes which however will remain for their specific product groups. when designing your figures and tables, etc

Comparison of advanced fuels—Which technology can win from the life cycle perspective?

Abstract Alternative drivetrains and advanced fuels are considered as promising methods for providing sustainable mobility. To understand the overall environmental impact of passenger vehicles on global warming potential (GWP) and primary energy demand (PED), a life cycle assessment (LCA) was conducted for currently popular sport utility vehicles (SUVs) and compared with that for compact cars. This LCA considered vehicle production as well as the use phase and fuel production; it is a well-to-wheel approach. To carry out this approach, different production processes of alternative vehicle types—plug-in hybrid (PHEV), hybrid (HEV), electric (EV), and fuel cell (FCEV) vehicles—were analyzed and compared with conventional internal combustion engine vehicles (ICEV). Furthermore, the emissions and PED due to the production and use of different advanced fuels, such as cellulosic bioethanol, biomass-to-liquid fuel, synthetic gases (methane and hydrogen) via power-to-X, and electricity from wind power, were compared with those of conventional gasoline, natural gas, steam-reforming hydrogen, and EU-28 electricity mix. It was found that alternative drivetrains, especially those for FCEV and EV, show a higher GWP during production of up to 50%. However, EVs have a 45% and FCEVs a 35% lower GWP than that of ICEVs, based on a lifetime of 200,000 pkm if operated with traditional fuels. Furthermore, the LCA shows that PHEVs, operated by electricity from wind and cellulosic bioethanol, exhibited the lowest GWP (33 gCO2, eq per pkm) of all analyzed SUV types. However, compact cars presented a different conclusion. For compact cars, EVs had the lowest GWP with 28 gCO2, eq per pkm. In terms of PED, a similar behavior to that of GWP was found.

What Will Be the Future of Powder Metallurgy?

Abstract Traditionally, powder metallurgy has been based on two major industrial sectors – ferrous precision parts and hardmetals. Both of them relied heavily on the automotive industry, with focus on internal combustion engines. Today, there is an increasing trend towards alternative drivetrain systems, and powder metallurgy faces the challenge to find new applications to replace those lost with the decrease of classical internal combustion drives. In this presentation it is shown that the main strength of powder metallurgy lies in its enormous flexibility regarding materials, geometries, processing and properties. This enables PM to adapt itself to changing requirements in a changing industrial environment. Examples given are PM parts in alternative drivetrain systems, new alloying concepts and processing routes offering distinct advantages. With hardmetals, innovative microstructures as well as sophisticated coatings offer increased lifetime, applications ranging from metalworking to rockdrilling and concrete cutting. A particularly wide area is found in functional materials which range from components for high power switches to such for fuel cells. Soft and hard magnets are accessible by PM with particularly good properties, PM having in part exclusivity in that respect, such as for NdFeB superhard magnets as well as soft magnetic composites (SMCs). Metal injection moulding (MIM) is gaining further ground, e.g. in the medical area which is a fast-growing field, due to demographic effects. Finally, most additive manufacturing techniques are powder based, and here, the knowledge in powder handling and processing available in the PM community is essential for obtaining stable processes and reliable products. Conclusively it can be stated that PM is on the way to fully exploit its potential far beyond its traditional areas of applications.

Model-based design validation for advanced energy management strategies for electrified hybrid power trains using innovative vehicle hardware in the loop (VHIL) approach

Hybridization of automotive powertrains by using more than one type of energy converter is considered as an important step towards reducing fuel consumption and air pollutants. Specifically, the development of energy efficient, highly complex, alternative drive-train systems, in which the interactions of different energy converters play an important role, requires new design methods and processes. This paper discusses the inclusion of an alternative hybrid power train into an existing vehicle platform for maximum energy efficiency. The new proposed integrated Vehicle Hardware In-the-loop (VHiL) and Model Based Design (MBD) approach is utilized to evaluate the energy efficiency of electrified powertrain. In VHiL, a complete chassis system becomes an integrated part of the vehicle test bed. A complete conventional Internal Combustion Engine (ICE) powered vehicle is tested in roller bench test for the integration of energy efficient hybrid electric power train modules in closed-loop, real-time, feedback configuration. A model that is a replica of the test vehicle is executed – in real-time- where all hybrid power train modules are included. While the VHiL platform is controlling the signal exchange between the test bed automation software and the vehicle on-board controller, the road load exerted on the driving wheels is manipulated in closed –loop real-time manner in order to reflect all hybrid driving modes including: All Electric Range (AER), Electric Power Assist (EPA) and blended Modes (BM). Upon successful implementation of VHiL, a comparative study between Rule Based (RB) energy management strategy (EMS) and Equivalent Consumption Minimization Strategy (ECMS) to Control Parallel Through-The-Road Hybrid Electric Vehicle (PTTR-HEV) is performed. The study shows that the actual fuel efficiency of the tested vehicle under both control strategies can be used in order to evaluate the effectiveness of energy conversion efficiency of the powertrain system. The fuel consumption of hybridized powertrain is compared with the conventional powertrain equipped in an actual vehicle to help comprehend the degree of efficiency attained by the hybridization. This process is developed in order to enable effective tuning/validation of advanced energy management strategies utilized in hybrid electric powertrain through an evaluation of a complete real chassis system subject to electric hybridization. The VHiL is considered as new evolution for the utilization of vehicle test bed as a predictive mechatronic platform for the development of energy efficient electrified propulsion systems and thus reduce cost and time.

Flywheel Hybrid Drives Compared to Conventional and Alternative Drivetrain Concepts

Flywheel Hybrid Drives Compared to Conventional and Alternative Drivetrain Concepts

On the relation between communication and innovation activities: A comparison of hybrid electric and fuel cell vehicles

The automotive industry has proposed and announced a number of technological innovations to reduce the environmental impact of transport. Whereas initially many of the proposed technologies were surrounded by very optimistic expectations, many technological innovations are not commercially available yet and expectations eventually turned into disappointment. The hypes concerning these alternative drivetrain technologies collapsed when optimistic announcements could not be met, within the proposed timeframe. This paper analyzes the relation between research and development activities (innovation activities) and communication activities in the automotive industry using patent statistics, press releases and interviews. The analysis reveals that the underlying characteristics of the specific technology have an influence on the relation between communication and innovation activities. When innovations depend on the build-up of a new infrastructure actors have a strong incentive to raise expectations. This suggests that the specific shape of the hype cycle is depending on the complexity of the technology.

A comparative analysis of well-to-wheel primary energy demand and greenhouse gas emissions for the operation of alternative and conventional vehicles in Switzerland, considering various energy carrier production pathways

This study provides a comprehensive analysis of well-to-wheel (WTW) primary energy demand and greenhouse gas (GHG) emissions for the operation of conventional and alternative passenger vehicle drivetrains. Results are determined based on a reference vehicle, drivetrain/production process efficiencies, and lifecycle inventory data specific to Switzerland. WTW performance is compared to a gasoline internal combustion engine vehicle (ICEV). Both industrialized and novel hydrogen and electricity production pathways are evaluated. A strong case is presented for pluggable electric vehicles (PEVs) due to their high drivetrain efficiency. However, WTW performance strongly depends on the electricity source. A critical electricity mix can be identified which divides optimal drivetrain performance between the EV, ICEV, and plug-in hybrid vehicle. Alternative drivetrain and energy carrier production pathways are also compared by natural resource. Fuel cell vehicle (FCV) performance proves to be on par with PEVs for energy carrier (EC) production via biomass and natural gas resources. However, PEVs outperform FCVs via solar energy EC production pathways. ICE drivetrains using alternative fuels, particularly biogas and CNG, yield remarkable WTW energy and emission reductions as well, indicating that alternative fuels, and not only alternative drivetrains, play an important role in the transition towards low-emission vehicles in Switzerland.

Noise emission assessment of a hybrid electric mid-size truck

In the attempt to improve urban environmental conditions, city or national incentives encourage the use of cleaner vehicles, including hybrid electric vehicles. This paper explores the actual noise impact of this alternative drivetrain technology on the noise emission of a mid-size delivery truck powered by a parallel hybrid powertrain, compared with an equivalent internal combustion engine truck on the basis of pass-by noise measurements. It investigates jointly the overall emission, the main noise sources and the vertical directivity of the vehicle. The essential benefit results from the existence of a full-electric mode below 50km/h, with a significant noise reduction which may exceed 8dB(A) at low constant speed. Even if smaller, this noise advantage is still valuable when the vehicle is accelerating or braking. Due to weaker noise emitted upwards, the benefit should be even greater for residents living on upper building floors. The rolling noise associated with the drive wheel/road contact is the main noise source in all driving situations in electric mode, and beyond 50km/h in the configurations with engine.