Browse Topic: Fuel economy

Items (7,953)
Series hybrid electric vehicles (HEVs) employ an electric motor for propulsion, while the internal combustion engine operates solely as a generator under energy-efficient speed and load conditions. Owing to this architecture, series HEVs can achieve high fuel efficiency with a relatively simple control structure. However, conventional energy management systems (EMSs) often prioritize battery state-of-charge (SOC) stabilization, which can lead to frequent engine start–stop operations and unnecessary fuel consumption, particularly in short-trip driving. This study aims to enhance energy management performance in series HEVs by optimizing engine power generation timing based on predicted short-trip duration. A computationally efficient, rule-based prediction model is developed using real-world driving data, in which short-trip duration is estimated from vehicle speed and acceleration. Due to its low computational load, the proposed model is suitable for implementation in an onboard electronic control unit (ECU). The proposed control strategy initiates engine power generation when the battery SOC is low and the predicted trip duration is long, and suppresses generation when the SOC is sufficiently high or the predicted trip is short. A detailed vehicle model incorporating an engine, generator, electric motor, inverter, and battery is developed in Modelica to evaluate the proposed strategy. Simulation results demonstrate that the proposed EMS significantly reduces the frequency of engine start–stop events, leading to fuel economy improvements of 3.6% under the WLTC (excluding the extra-high phase) and 13.4% in a real-world urban–rural driving cycle, compared with a commercialized baseline vehicle. These results confirm the effectiveness and practical applicability of the proposed EMS for passenger vehicle applications.
Mizushima, NorifumiSato, AkiraKuboyama, TatsuyaMoriyoshi, Yasuo
Hybrid electric vehicles rely heavily on battery pack power capability, which is often compromised by non-uniform aging and thermal gradients. Conventional battery models typically use bulk state-of-health metrics, failing to capture localized degradation that leads to current imbalances and reduced pack utility. This paper presents a multi-scale modelling framework that integrates Electrochemical Impedance Spectroscopy data into a fractional-order equivalent circuit model to simulate localized degradation in Lithium Iron Phosphate cells. Results show that the terminal voltage of LFP cells can be accurately modelled using the proposed fractional-order equivalent circuit with a discrete transfer-function implementation, maintaining root-mean-square errors below 20 mV across most state-of-health and state-of-charge conditions. The validated cell model is then extended to a degradation-aware battery pack representation. The battery pack in this work utilizes a 200-kWh, 800 V architecture consisting of five modules connected in parallel, each module composed of 13 parallel strings of 250 series cells, evaluated under multiple degradation scenarios. By integrating this pack model into a Class-8 series hybrid powertrain simulation, this study quantifies how cell-to-cell heterogeneity impacts vehicle performance under the VECTO regional delivery drive cycle. At the vehicle level, these battery constraints influence engine duty cycles and battery pack stress metrics. When localized degradation reaches up to 40% in one module while the remaining modules degrade up to 20% to 30%, such inhomogeneous degradation reduces the minimum pack terminal voltage by approximately 27% and increases peak discharge current by more than 30%, resulting in more rapid degradation. These battery-level limitations translate into higher fuel consumption by up to 6% in a charge-sustaining scenario.
Safavi, Seyed RezaHomayouni, HoomanShoa, TinaWang, JasonMcTaggart-Cowan, Gordon
The ongoing efforts for reduction of the traffic-related greenhouse gas emissions and, at the same time, the mitigation of harmful pollutant emissions from vehicle exhaust emissions are important development tasks for the entire automotive industry worldwide according to demand to provide clean and efficient products. Further tightened fleet average FE standards and ultra-low limits for exhaust emissions require the continuous development of new propulsion system types. Due to the given reluctance of the end customer and corresponding low acceptance of fully electrified vehicles, especially in the commercial vehicle segment, new and innovative topologies are needed to meet regulatory requirements and maintain the high versatility of today’s dominating solutions. For further optimization of operating conditions with enhanced fuel efficiency, the technical strategy is also determined by uplifting the attractiveness of electric driving incl. the avoidance of areas with poor ICE efficiency and as well as the coverage of emission-critical operations by electric propulsion. In this context, the support provided by an electric drive on board the vehicle in a combined drive system is becoming increasingly important. This article discusses accordingly various platform strategies for hybridized Diesel powertrains in different sectors of commercial vehicle applications and delivers a comprehensive comparative analysis of different hybrid drive concepts. Specifically, several hybrid powertrain configurations that extend an electric drive platform (hybridized BEVs), such as series and parallel-series topologies, are compared with traditional parallel hybrid powertrain topologies based on internal combustion engines (ICE). The study focuses mainly on two different cornerstone applications: a large light commercial vehicle, ranging from 3,5 to 6,5 to. and a heavy-duty long-haul truck with 40…44 to. gross vehicle weight. It evaluates the advantages in terms of CO2 emissions and Diesel fuel savings and investigates the effects on emission controls aspects. In addition to technical comparisons, the paper addresses also regulatory demands and end customer merits, assessing the integrational effort and commonalities in components with pure ICE and battery electric topologies. Furthermore, it explores the additional impact of advanced operational strategies for Hybrid Diesel powertrains, incorporating insights from innovative observations from executed hybrid technology demonstrator vehicles.
Koerfer, Thomas
The reduction of Greenhouse Gas (GHG) emissions represents a key challenge for the transportation sector, requiring the adoption of renewable fuels capable of ensuring both environmental benefits and compatibility with existing internal combustion engine technologies. In this context, bioethanol emerges as a viable solution for Spark Ignition (SI) engines, offering a low life-cycle CO₂ footprint and favorable combustion characteristics. Nevertheless, despite its well-known advantages under steady-state operation, the widespread use of high-ethanol-content fuels is still limited by critical issues during engine cold start. The aim of this work is to experimentally investigate the influence of ethanol content on cold-start behavior and idle warm-up transient operation of a Naturally Aspirated (NA), Port Fuel Injected (PFI) SI engine. The experimental campaign was carried out under idle conditions using four fuels with increasing ethanol content, namely commercial gasoline (E5), E30, E60, and neat ethanol (E100). Cold-start and full warm-up tests were performed starting from ambient temperature, while additional dedicated experiments were conducted on E100 to evaluate startability under different initial engine wall temperatures. The results show that increasing ethanol content has a limited impact on the overall warm-up duration, while slightly reducing engine wall and exhaust gas temperatures. Conversely, E100 exhibits pronounced startability issues at low initial wall temperatures, requiring multiple cranking attempts to achieve stable idle operation. A minimum wall temperature threshold in the range of 25-30 °C was identified as necessary to ensure reliable cold start with E100. The outcomes of this study provide experimental evidence of the key role played by engine thermal conditions in enabling stable operation of ethanol fueled SI engines during cold start.
Falbo, LuigiFalbo, BiagioPerrone, DiegoCastiglione, Teresa
Heavy-duty vehicles significantly contribute to greenhouse gas emissions and urban air pollution, especially during cold-starts and transients when engine and aftertreatment efficiencies drop. Waste heat recovery (WHR) via Organic Rankine Cycle (ORC) systems offers a practical solution to improve fuel efficiency and cut CO₂ in real-world heavy-duty operations. This study examines ORC-based WHR integration into conventional and hybrid powertrains of an Isuzu FTR850 truck, analyzing four configurations: Shell-and-Tube or Plate heat exchangers with simple or regenerative ORC layouts. For hybrids, it compares two engine sizes and energy management strategies: an optimized fuzzy logic approach versus constant-power operation to enhance exhaust heat recovery. A validated quasi-static simulation framework is used to predict fuel consumption and exhaust properties over representative duty cycles. 2D performance maps using exhaust temperature and mass flow as inputs are used to model the WHR under off-design conditions. Results show that the recovery of waste heat WHR depends on the hybridization level and strategy. Conventional powertrains benefit most from Shell-and-Tube exchangers, recovering ~2 kWh of electrical energy per 8-hour cycle and reducing fuel consumption by 0.5%. Hybrid setups recover up to 3.9 kWh from exhaust gases with a simple layout coupled with a Shell-and-Tube heat exchanger under constant-power control. Electricity is used to support onboard auxiliaries and battery charging, further lowering fuel demand (-44%) and emissions. Finally, a multi-objective optimization was performed to exploit the synergy between hybridization and WHR while maintaining acceptable payload and battery operating conditions.
Donateo, TeresaMorrone, Pietropaolo
ZF foresees hybrid powertrain technology becoming more popular for commercial transport in the coming years, and it's working earnestly to be a major player in that realm. The supplier unveiled the TraXon 2 Hybrid transmission to the North American commercial vehicle market at last year's ACT Expo and is now evaluating the technology in real-world conditions. The next-gen automated manual transmission (AMT) is optimized to improve fuel efficiency for plug-in and full hybrid heavy-duty trucks and coaches, as well as special applications such as medium- to heavy-duty mobile cranes.
Gehm, Ryan
Volvo Trucks' revised VNR brings updated safety tech, improved fuel economy and driver comfort features to the regional haul segment. Volvo Trucks has continued its rollout of new models for every sector of the commercial truck market. The redesigned VNR is the latest model to see the spotlight. The new VNR naturally carries all of Volvo's latest safety tech, but also prioritizes maneuverability, fuel efficiency and configurability for a wide variety of fleet uses. “The VNR is an incredibly versatile truck,” said Maddie Sullivan, product marketing manager. “There are so many different configurations to meet our customer's needs. We offer four different cab sizes, three different axle configurations and two different chassis configurations.”
Wolfe, Matt
Sustainability needs to be practical. That was a point Peter Voorhoeve, president of Volvo Trucks North America, made clear at CONEXPO 2026 in Las Vegas. “We're running a business, so we are focusing a lot on efficiency and uptime,” he said, referencing the up-to-10% improvement in fuel efficiency with the new VNL. “That helps our customers to run their operations at a better pace and a lower cost, but at the same time we have a very positive impact on the climate.” Voorhoeve also teased the launch of a new vocational truck. “We are strong in long haul. We are a leading sleeper manufacturer, very strong in regional haul, and we now have renewed focus on vocational,” he said. “In August we will launch a new truck specifically for the vocational segment that's built on the same platform as the VNL and VNR.” (See page 22 for our feature story on the new VNR.)
Gehm, Ryan
Against the backdrop of growing global demands for energy sustainability and stricter emission regulations for diesel engines, this study investigates the performance implications of incorporating cyclohexanol—a renewable oxygenated fuel—into diesel fuel blends. Using a marine medium-speed diesel engine as the experimental platform, the research systematically evaluates engine performance and emission characteristics across a range of cyclohexanol-diesel blend ratios under low, medium, and high load conditions. Experimental findings reveal multifaceted effects of cyclohexanol blending on engine operation. Combustion of the blended fuels enhances the engine’s dynamic performance, particularly under medium and high loads, where the maximum in-cylinder burst pressure exhibits a noticeable increase. This improvement is attributed to cyclohexanol’s oxygen-carrying capacity, which promotes more vigorous and sustained combustion reactions. In terms of emissions, increasing the proportion of cyclohexanol in the fuel blend leads to significant reductions in soot and carbon monoxide (CO) emissions, reflecting the cleaner-burning properties of the oxygenated component. However, this is accompanied by an uptick in nitrogen oxide (NOx) emissions, likely due to the elevated combustion temperatures generated by the more efficient fuel oxidation process. From an economic perspective, cyclohexanol blending at consistent load levels induces a postponement in the crank angle at which peak heat release occurs during combustion. This temporal shift prolongs the effective combustion duration, enabling more complete fuel utilization within the cylinder. Consequently, fuel consumption rates decrease, and overall engine efficiency improves, highlighting the potential of cyclohexanol blends to enhance operational economy in marine propulsion systems. In summary, this study underscores the complex trade-offs associated with cyclohexanol-diesel blends: while they offer tangible benefits in power output, fuel efficiency, and reduced particulate emissions, managing the increase in NOx emissions remains a critical challenge. The results provide a foundational framework for advancing biofuel applications in marine engines, emphasizing the need for integrated emission control strategies to optimize the balance between performance and environmental sustainability.
Chen, KeYang, ChenxiWang, YibinFan, JinyuLiu, YuchenYe, ZixiaoHuang, Jialiang
To reduce high NOx emissions from diesel-cyclohexanol blends, this study employed a marine medium-speed diesel engine as the experimental platform. An in-cylinder combustion model was developed and meshed using AVL - FIRE software, with model validity validated against experimental data. Tests were conducted at four load conditions (25%, 50%, 75%, and 100% load) with a 30% cyclohexanol blend (C30) and four EGR rates (0%, 7.5%, 10%, and 12.5%) to analyze combustion characteristics, emissions, and fuel economy. The results showed that the introduction of EGR had a striking inhibitory effect on NOx emissions. At 100% load with 12.5% EGR rate, NOx emissions were substantially reduced compared to baseline operation without EGR. However, EGR implementation led to delayed ignition timing, reduced in-cylinder pressure, and worsened fuel economy. Therefore, an appropriately calibrated EGR strategy can effectively reduce NOx emissions, though it requires optimization to mitigate adverse effects on combustion performance and efficiency.
Liu, YuchenYang, ChenxiFan, JinyuChen, KeYe, ZixiaoHuang, Jialiang
Aerodynamic simulations are crucial in vehicle design and performance evaluation. Traditionally, these simulations utilize Computational Fluid Dynamics (CFD) techniques to compute flow quantities such as velocity, pressure, and wall-shear stresses. Accurate prediction of these quantities is vital for estimating drag and lift forces, which directly impact fuel efficiency, stability, and acoustics. This study focuses on developing an AI surrogate for aerodynamic design of production mideo-size SUVs using NVIDIA’s PhysicsNeMo framework. Firstly, high-fidelity 3D CFD data are generated using first-principles solvers on 102 different geometry variants at a uniform inlet velocity of 38.89 m/s and a fixed set of boundary conditions. The DoMINO (Decomposable Multiscale Iterative Neural Operator) AI model, part of the PhysicsNeMo framework, is then used to train on this dataset, accurately predicting surface pressure and flow fields around vehicles for rapid estimation of critical aerodynamic metrics such as drag and lift. DoMINO is a neural operator that learns local geometry representations from point cloud data and predicts PDE solutions on discrete points using dynamically constructed computational stencils in local regions. By leveraging both short- and long-range geometric features, the DoMINO model predicts solution fields on the vehicle’s surface and in the surrounding flow domain—capabilities essential for informed design and engineering decisions in industrial applications. In this study, the DoMINO model is evaluated on a realistic production mid-size SUV vehicle designed by General Motors. Comprehensive hyperparameter tuning is conducted to optimize model performance, along with an analysis of input grid sensitivity. The findings highlight DoMINO's effectiveness as a robust and accurate tool for aerodynamic analysis in the automotive sector, enabling accelerated design cycles and enhanced vehicle performance.
Keum, SeunghwanRaul, VishalGrover, RonaldParrish, ScottRanade, RishikeshGhasemi, AbouzarKamenev, AlexeyTadepalli, Srinivas
MSIL (Maruti Suzuki India Limited), India’s leading automotive manufacturer, offers a diverse range of SUVs (Sports Utility Vehicles) in its portfolio. Traditionally, SUVs are associated with an assertive stance and a commanding road presence; however, this bold design language often compromises aerodynamic drag performance. Over the past decade, demand for this segment has surged, while CAFE (Corporate Average Fuel Economy) regulations have become increasingly stringent. To address this growing market need, MSIL conceptualized a new SUV - Victoris - targeted to deliver best-in-class aerodynamic efficiency in MSIL SUV portfolio. This paper details the aerodynamic development process using CFD (Computational Fluid Dynamics) and full-scale WTT (Wind Tunnel Testing). Initially, the aggressive styling of Victoris negatively impacted drag performance. Strategic exterior surface refinements and integration of aero components enabled recovery of aerodynamic efficiency. Key interventions included redesigned front and rear bumpers, roof-end treatment, quarter spoiler profiling, bumper corner vents, and aero-cut alloy wheels. Victoris successfully retained its bold styling while meeting ambitious aerodynamic targets. The optimized aerodynamic silhouette comprising hood-to-windshield transition, roof contouring, backdoor spoiler, and side body profiling - along with underbody elements such as covers, strakes, and air curtains improved drag performance by 14% compared to the initial design. Achieving this improvement required significant shape modifications and aero part additions without compromising SUV identity. This paper explains how these measures were implemented and the resulting airflow characteristics.
Dey, SukantaSingh, ShekharKumar, ChandanAlphonse, Felix Regin
Vehicle testing for fuel economy and emissions is typically performed indoors over standard dynamometer drive schedules to minimize variability and maximize repeatability of the results. In contrast, during on-road operation, operational parameters such as vehicle speed and acceleration and environmental factors such as temperature and wind will change unpredictably. These factors influence vehicle fuel economy and emissions, making on-road operation much more variable than dynamometer results. However, even though on-road conditions may be unpredictable, the on-road operational data can still be used to characterize vehicle performance. This paper describes the development of an on-road vehicle test methodology, with a focus on accounting for on-road factors with a high degree of accuracy while requiring only an achievable and reasonable amount of data. To develop this methodology, a 2016 Honda Civic was instrumented and driven multiple times over a route covering urban, rural, and freeway segments. Vehicle operational data, environmental conditions, fuel consumption, and emissions were recorded. The route was divided into segments and drive cycle parameters were calculated for each segment. Simple empirical equations were developed for this vehicle correlating fuel consumption with drive cycle parameters and the environmental conditions. The empirical models were compared to fuel consumption data from dynamometer tests with good results. Criteria pollutants (CO, NOx, and THC) were also measured and compared to dynamometer data. Finally, the amount of testing and data required to adequately characterize vehicle performance is discussed.
Moskalik, AndrewBarba, Daniel
There is an increasing adoption of Direct-Injection Spark-Ignition (DISI) engines in the market, which per 2024 US Environmental Protection Agency (EPA) Automotive Trends Report represents 73% of new vehicles sold in the US. And while it is well accepted that DISI offers advantages over Port Fuel Injection (PFI) technology in meeting stringent CO2 emissions and fuel economy requirements set by the EPA, DISI engines are also associated with increased formation of injector deposits. These deposits may foul injectors and accumulate on the injector tip causing distorted spray patterns and diffusive combustion. Ultimately, this leads to engine performance deterioration and increased harmful emissions. To control deposit formation, detergent-type chemistries are added to the fuel in small amounts. Deposit Control Additives (DCAs) function by preventing the formation of deleterious injector deposits as well as removing existing ones. This study used standardized protocols describing the assessment of DCA in controlling injector deposits that have been developed by industry in both the US and Europe. When used at standard concentrations, DCA showed some engine performance and emission benefits over untreated base fuel. This investigation also demonstrated that engine performance can be recovered, in an engine with fouled injectors, with the use of higher DCA concentrations, accompanied by improved fuel economy and reduced particulate and total hydrocarbon emissions. This further confirms previous findings that, although DCA increases gum levels in the fuel, higher concentrations of DCAs improve injector cleanliness enough to outweigh any negative impacts from the increased gum content.
Soriano, NestorWilliams, RodCracknell, RogerLang, WendyChahal, Jasprit
Effective thermal management in internal combustion engines is essential for meeting increasingly stringent emissions regulations and achieving fuel efficiency improvements. This study introduces a novel and comprehensive approach to optimize engine thermal management by addressing key system components, including coolant circuit design, Integrated Thermal Management Module (ITM) control strategies, port-specific flow management, zero-flow operation techniques, and HVAC (Heating, Ventilation, and Air Conditioning) settings standardization. Unlike previously published works, this study focuses on reducing coolant circuit thermal mass to accelerate engine and component warm-up, refining ITM control logic through linear mapping and advanced signal filtering for precision, and enhancing zero-flow operation for minimizing lubricant oil dilution during start-up and reducing heat loss under low ambient conditions. Additional optimizations include port-specific adjustments and radiator flow distribution strategies to improve system responsiveness and fuel economy. Standardized HVAC configurations were implemented to ensure reproducibility across WLTP vehicle and bench testing scenarios. The methodology validated key improvements through rigorous testing on a newly developed engine platform and demonstrated scalability by successfully integrating these measures into vehicles designed to comply with EU7 regulations. Results indicate substantial gains in warm-up performance, coolant temperature control stability, energy efficiency, and regulatory compliance. Furthermore, these advancements underscore their practical application for automakers seeking novel solutions to meet evolving environmental standards and enhance market competitiveness. Overall, this study presents a set of scalable and widely applicable strategies for modern spark-ignition engines, supporting both new engine development and optimization of existing engines, while addressing global fuel-efficiency and emissions challenges effectively.
Lee, ChangjooLee, KyuminKim, SeonyeongNam, ChoonhoYoo, Jihun
This study estimates the impact on driving energy of differences in aerodynamic characteristics for yaw angle from natural wind during North American Highway mode driving. A previous study [1] clarified the potential to estimate the fuel consumption impact of natural wind by integrating the drag coefficient yaw characteristics and yaw angle occurrence probability. The natural wind was measured on a vehicle while driving a representative North American Highway test course [2]. Driving energy is predicted from the obtained yaw probability and the drag coefficient yaw sweep data in a wind tunnel. Measurements were conducted every weekday for 8 hours in 2023, covering 70% of the traffic volume. The validity of the measurement period was evaluated by the deviation from the annual average of wind direction and speed. Since yaw probability varies depending on the road environment, it is necessary to weigh the road environment type probability when calculating the driving energy. The probability was calculated using machine learning from more than 490,000 images of North American Highways. Based on the obtained natural wind data, a yaw probability model was created for each vehicle speed in the US Highway driving mode. An evaluation method for the driving energy was constructed from data before and after the improvement of the drag coefficient yaw characteristics. This evaluation method is based on verification results from actual driving data. By using the yaw probability distribution that considers the road environment and traffic volume of the North American highway, the impact of the yaw angle due to natural wind on driving energy can be numerically estimated. According to this method, for a specific the drag coefficient yaw sweep characteristic with a 13 ct improvement in the drag coefficient at a 6-degree yaw angle, this would result in an improvement in drive energy of approximately 1% on real US highways. This is an important indicator for optimizing aerodynamic characteristics, and suggests a development direction that can improve fuel efficiency in the real world by optimizing the vehicle shape while taking into account the yaw angle caused by natural wind.
Onishi, YasuyukiNucera, FortunatoNichols, LarryMetka, Matt
Since air drag is proportional to the square of the speed, it is expected that reducing air drag will significantly improve fuel efficiency for on-highway trucks and buses, which are often driven at high speeds. Therefore, the purpose of this study is to propose an optimization method for vehicle shape to drastically reduce aerodynamic drag in heavy-duty vehicles. Using NSGA-II, one of a genetic algorithm, the overall vehicle shape was optimized with drag coefficient (CD) and lift coefficient (CL) values as objective functions and design variables as parameters in a total of 13 locations. Among the Pareto solutions, an 86% reduction in CD was achieved compared to the base shape when the CD value was the lowest. Since the CL value remains low with this shape, it can be seen that driving stability does not deteriorate. Among the design variables in optimization, it was confirmed that the corner radius of the vehicle side was particularly effective in reducing the CD value. In addition, when optimizing only the cab shape, the optimal value for the front virtual angle was 30 deg., but in relation to the corner radius, the value for this optimized shape was around 40 deg. The CD value of a 1/20 model of the optimized shape was measured in a wind tunnel test and compared with the optimization results from the aforementioned numerical analysis. As a result, the CD value reduction effect of the optimization shape was confirmed in the wind tunnel test as well, demonstrating the validity of the optimization results described above. In addition, an investigation into the yaw angle dependency of the optimized shape revealed that adding a yaw angle provided a sailing effect that reduces CD. A program for calculating fuel consumption rates for heavy-duty vehicles was used to compare fuel efficiency when using the base shape and the optimization shape. The weighted average fuel economy in urban driving (JE05) and interurban driving (highway) modes was improved by approximately 21% using the optimization shape.
Kawano, Daisuke
Building upon previous work that successfully employed a Reinforcement Learning (RL) agent for the autonomous optimization of transmission shift programs to enhance fuel efficiency, this paper addresses a critical limitation of that approach: the neglect of human-centric factors. While the prior methodology achieved substantial fuel consumption reductions by training an RL agent in a Software-in-the-Loop (SiL) environment, it did not explicitly account for aspects such as driver comfort and preferences, which are paramount for real-world user acceptance and drivability. This work presents a multi-objective optimization framework extending the artificial calibrator to simultaneously maximize fuel efficiency and enhance driver comfort. The method introduces a modified RL reward function that penalizes undesirable shift behavior to ensure a smooth driving experience (drivability). This new methodology also incorporates a mechanism to capture and integrate driver preferences, moving beyond a purely quantitative fuel-economy-driven objective to a holistic, user-focused calibration. Experimental evaluation demonstrates that the extended framework successfully generates a shift strategy that achieves a favorable trade-off between fuel efficiency and drivability, resulting in a more balanced and practical calibration. The ability to integrate these qualitative factors into an automated, data-driven process represents a significant step forward, promising to accelerate the development of powertrain control systems that are both highly efficient and aligned with the expectations of human drivers. This work lays the foundation for future RL-based calibration tools that are capable of addressing the full spectrum of development objectives, from fuel economy to the subtleties of vehicle drivability.
Kengne Dzegou, Thierry JuniorSchober, FlorianRebesberger, RonHenze, RomanSturm, Axel
Hybrid mining trucks, as core equipment for mine transportation, face high energy consumption and significant fluctuations in power demand during cyclic operations due to prolonged exposure to demanding operating conditions characterized by heavy loads and variable working conditions. To address the issues of high energy consumption and significant fluctuations in power demand during the cyclic operation of mining trucks, this paper proposes a hybrid mining truck energy management strategy based on global SOC (State of Charge) planning and neural network optimization control. First, a powertrain model was developed for a typical operating cycle of a hybrid mining truck, and its accuracy was validated by comparing it with experimental data. Using dynamic programming algorithms to plan the SOC for single-cycle operations provides a rational reference for energy allocation across different operational phases of mining trucks during a single cycle. Next, using the powerful nonlinear mapping and self-learning capabilities of neural networks, the system learns the optimal power output sequence of the range extender during offline computation. This enables rapid decision-making and adaptive adjustment of power allocation between the range extender and battery in real-time applications, thereby effectively reducing energy consumption under cyclic operating conditions. Design a SOC tracking controller to adjust the output of the neural network optimization controller, thereby achieving tracking of the planned global SOC. Finally, validated through simulations and real vehicle tests, the proposed energy management strategy can improve fuel economy, achieving a 1.27% fuel saving compared to traditional rule-based strategies in real vehicle tests. This study provides a feasible energy management scheme for the green and efficient operation of heavy mining vehicles.
Yang, JianyuZhao, ZhiguoChen, HuiyongLi, TaoZhuang, WenyuShen, PeihongTang, Peng
Hybrid-electric vehicle (HEV) fuel economy test procedures require that the net energy change (NEC) of the battery not interfere with measuring accurate fuel consumption results. SAE J1711-2010 required the NEC to stay within 1% of fuel energy consumption, assuming that residual changes in state of charge (SOC) would have negligible impact. In practice, however, the asymmetry between fuel and electricity conversion efficiencies means that an imbalance of one unit of battery energy can translate into a likely fuel consumption error of roughly three units. A standard S-Factor, a dimensionless ratio of marginal fuel change to marginal NEC change, was introduced in J1711-2023 to improve SOC correction procedures. The method improves upon the previous J1711 (2010) accuracy by correcting all results for NEC changes and expands the NEC-to-fuel ratio (NECFR) window, enabling HEVs to use electric propulsion more aggressively and potentially achieve higher fuel economy in testing and real-world usage. Using a standardized value (instead of requiring additional testing to determine the vehicle-specific value) provides a simple, low-burden approach across HEV designs. Empirical data, supported by simulations of HEV powertrains, indicate that there exists a practical range of S-Factors common to efficient HEV designs. The standard value represents a defensible best estimate within this range, close enough to provide corrected results with minimal error. The method also allows the NECFR window to be doubled (e.g., from ±1% to ±2%) while improving the fidelity of final fuel consumption results compared with the legacy procedure. This paper reviews the data and simulation work used to identify practical S-Factor values, evaluates the resulting correction accuracy across vehicle types and test cycles, and demonstrates that a single standardized S-Factor provides consistent results within an expanded NECFR window.
Duoba, Michael
Compared to regular fuels, biofuels can play a key role as low-carbon transitional energy sources for ICE vehicles as the fleet moves towards increasing electrification. Blending of ethanol plays a key role in enhancing the anti-knock properties of the fuel and also allows renewable hydrocarbons (such as bio-naphtha) to be incorporated into the blend whilst maintaining an acceptable overall fuel quality. Super lean burn ICE technology with λ between 2 and 3 can lead to enhanced fuel economy and reduced NOx emissions. The Toyota prototype engine used to generate data for this project injects most of the fuel in PFI mode to generate a homogeneous super-lean charge in the cylinder, but just before spark ignition the DI injector sprays a small amount of fuel towards the spark plug to create a richer charge near the spark plug to promote flame kernel development. Various fuel formulations with high biofuel content were tested in both conventional and super lean burn engines. Certain fuel compositions were formulated with faster burning components such as ethyl benzene. The super lean burn engine showed a clear link between faster combustion and minimization of unburned fuel losses, thereby resulting in a further efficiency benefit. The effect of fuel composition on particulate emissions was more complex: although the conventional engine emitted higher particulate numbers (PN) when operating on fuels with a higher content of heavier aromatics (as might be predicted from standard particulate index approaches), the super lean burn engine suggests that additional factors are at play which are discussed in the paper.
Aradi, AllenKrueger-Venus, JensJain, Sandeep KumarCracknell, RogerKolbeck, AndreasShibuya, MasahikoYamada, RyotaMatsubara, NaoyoshiKitano, Koji
Lightweighting of components has become a key challenge in the development of modern transportation systems. In the automotive and aerospace industries, the overall mass of a vehicle has a significant impact on its fuel efficiency and manufacturing cost. Therefore, the lightweight design of vehicle components is crucial in the industrial field. Topology optimization (TO) is a computational design approach aimed at achieving lightweight designs. However, most existing studies focus on simplified academic models, with limited demonstration in real-world applications. This paper presents a revised TO workflow to obtain production-ready design and a practical implementation of TO in the design of three structural components in the aerospace industry: seatback frame, seat fuselage mount, and seat spreader. The revised TO workflow incorporates the practical demands of industry, including enhanced manufacturability and cost efficiency through TO design. The resulting designs are evaluated to ensure all regulatory requirements are satisfied. Comparative results show that the designs produced by the presented TO-based design method achieve a significant weight reduction of 50% for the seatback frame. For the seat fuselage mount and seat spreader, the proposed method produced designs with a weight comparable to the baseline while satisfying stricter crashworthiness requirements. These components also ensure manufacturability, efficient fabrication cost, and compatibility with family parts. These findings demonstrate that TO can deliver production-ready solutions without compromising structural performance. The study highlights the potential of integrating TO into a revised design workflow to support performance-driven development of complex, production-ready industrial components.
Lee, Hanbok JakeShi, YifanGray, SavannahOrr, MathewPark, TaeilWotten, ErikLeFrancois, RichardHuang, YuhaoPatel, AnujKim, HansuJalayer, ShayanBurns, NicholasHansen, EricGrant, RobertKok, LeoKim, Il Yong
The damper system in a hybrid TMED system reduces engine-induced vibration and damps the rapid torsional torque applied by the motor through spring stiffness. Furthermore, the built-in damper system of the P1+P2 TMED-II hybrid system offers improved fuel efficiency compared to the external damper system of the existing P0+P2 TMED-I. Although the internal layout of the transmission is limited, the built-in damper system was redesigned to accommodate installation between the P1 and P1 motor. However, CAE analysis techniques for damper systems are currently not clearly defined, and research data on their strength under rotational torque loads are lacking. To reduce development costs and provide direction, CAE analysis technology development and validation are necessary. In this study, a finite element model of the damper system was developed and compared with experimental results to ensure CAE reliability. Furthermore, based on the validated model, structural and fatigue durability analyses were performed, attempting to replace test-driven R&D methods with CAE. Additionally, we used Design of Experiments (DOE) to determine the impact of structural analysis stresses on the design parameters of the embedded damper system. Through this process, we selected an optimal model that minimized stresses, and verified the improvement effects through analysis of this model.
Sun, Hyang SunGanesan, Karthikeyan
This paper presents research and digital twin modeling results to support work on a methodology to properly account for the energy consumed by the thermal system of a BEV, for use within both existing Petroleum-Equivalent Fuel Economy (PEFE) calculations, and the proposed addition of hot and cold weather range values to the consumer-facing Monroney label [1]. Properly accounting for thermal system impacts would incentivize minimizing energy consumption of these systems, since 1) BEV PEFE is a direct input to an OEMs overall CAFE performance, and 2) the values on the Monroney label has some impact on consumer vehicle choice. The impetus for this work was Final Rules issued by the EPA and NHTSA in early 2024 eliminating A/C Efficiency Credits for BEVs from the 2027 MY, thus eliminating regulatory incentives to minimize energy consumption of these systems. Higher energy consumption will produce a number of negative secondary effects, including higher real-world greenhouse gas emissions, reduced vehicle range, greater strain on the nation’s electrical grid, and higher vehicle mass leading to reduced vehicle safety - should OEMs opt to merely install larger batteries to address cold and hot weather range impacts instead of implementing lower energy-consuming technology. The results from the analysis, which ideally would be confirmed with follow-up vehicle tests, show that for a baseline, PTC-heat based system, thermal system energy consumption represents 19.2% of the total energy consumed by a BEV on an annual basis, using an ambient-VMT weighted approach. It seems to be the technical equivalent of “straining at a gnat while swallowing a camel” to focus so much time and energy on identifying incremental improvements in energy consumption from the propulsion-portion of a BEV, while by comparison ignoring the system that according to this analysis can account for nearly 20% of the total on an annual basis.
Taylor, Dwayne
The application of multiple materials in vehicle bodies is accelerating as the adoption of lightweight aluminum alloys and composite materials advances rapidly. These materials play a crucial role in reducing overall vehicle weight, enhancing fuel efficiency, and complying with increasingly strict environmental regulations. As the automotive industry continues to evolve toward electrification and sustainability, the integration of lightweight and high-performance materials has become a key design strategy. However, the use of multiple materials creates new challenges in manufacturing, particularly for joining technologies. Since different materials have varying mechanical properties, thermal behavior, and surface characteristics, the selection of appropriate joining methods is essential for ensuring structural integrity and durability. Depending on material types, thicknesses, production processes, and cost constraints, various joining techniques—such as mechanical fastening, welding, and adhesive bonding—are selectively applied. This study focuses on fatigue life prediction for point-based joints commonly used in automotive structures, including flow drilling screws (FDS), blind rivets, and blind nuts. Fatigue fractures in these joints typically propagate in multiple directions: through the sheet thickness and along the in-plane direction. Accurate fatigue life prediction requires numerical simulations that account for both crack propagation paths and the interaction of these paths with joint geometry and loading conditions. Traditional fatigue models often assume a single fracture mode, limiting the ability of these models to evaluate multiple failure mechanisms simultaneously. To address this issue, this study proposes a simplified modeling approach that enables the simultaneous consideration of multiple fracture modes. This paper introduces a numerical analysis-based method capable of predicting the fatigue strength of point joints, and describes the fatigue tests that were conducted to validate the proposed approach. This research contributes to the development of more reliable and efficient design strategies for multi-material automotive structures.
Takuno, SougoIsono, ToshiyukiUrakawa, KazushiGoto, SuguruKawamura, HiroakiNiisato, EitaIshigami, Yuta
Towing imposes substantial efficiency penalties on both battery-electric vehicles (BEVs) and internal combustion engine (ICE) vehicles, reducing range by 30-50%. This paper presents a proof-of-concept embedded control architecture for distributed trailer propulsion that actively regulates drawbar force to reduce towing loads. Unlike proprietary e-trailer systems requiring specialized hardware, the proposed implementation demonstrates feasibility using commercial off-the-shelf (COTS) components and open-source software. The distributed architecture employs dual Raspberry Pi 4B single-board computers communicating via ROS 2 at 20 Hz. The trailer-mounted controller executes a Simulink-generated control node coordinating load cell acquisition (HX711 ADC), motor CAN bus telemetry, and throttle commands to a 5 kW BLDC traction motor powered by a 5 kWh LiFePO4 battery pack. A vehicle-mounted controller logs OBD-II/CAN validation data. The control pipeline implements cascaded EWMA/Hampel digital filtering with intentional phase lag for hitch-force regulation. The system was validated through on-road testing with an ICE towing vehicle pulling a 1,000-lb trailer over standardized 2.1 km segments following SAE J1321 Type II procedures. Preliminary trials demonstrated stable control performance with drawbar force regulation with no oscillatory behavior. Fuel consumption measurements showed promising improvements (9.4% lower fuel consumption in assisted vs. baseline conditions), though limited sample size precludes definitive causal claims. The primary contribution is establishing technical feasibility of cost-effective COTS implementation (USD 5,000 hardware cost) for trailer propulsion control, providing a foundation for expanded validation studies and commercial deployment pathways.
Joshi, GauravAdelman, IanLiu, JunDonnaway, Ruthie
This article investigates the optimization problem of fuel economy for heavy-duty commercial vehicles. A Dynamic Programming–Based Fuel-Saving Predictive Cruise Control (DP-FSPCC) method is proposed, which is based on the Bellman optimality principle and uses the cost function to evaluate the optimal feedback control gain, thereby improving the fuel economy of heavy-duty commercial vehicles on complex roads with varying slopes. To address the issues of low accuracy in road feature representation and poor adaptability to different driving conditions in existing slope reconstruction algorithms, the road ahead is dynamically segmented for high-precision processing by integrating ADASIS (Advanced Driver Assistance Systems Interface Specifications) map information with significant turning point detection and dynamic sensitivity analysis. An engine fuel consumption mapping model based on local gradient information is established to provide an accurate cost function for dynamic programming. Furthermore, a feedforward optimization mechanism based on slope classification is proposed. This mechanism adopts a differentiated cost function weight design strategy for different road conditions, making the control strategy more in line with actual driving experience, effectively reducing the computational complexity of dynamic programming and improving the real-time performance and optimization efficiency of the algorithm. Finally, through numerical simulations and real-vehicle tests on highways, the effectiveness and superiority of the proposed method are verified.
Jin, DapengShuai, YueWu, XinJia, TongQiao, ZhiyuanChang, ShiweiMu, Tong
Gasoline direct injection (GDI) engines are the most common technology on American roadways in 2025, and soon, an industrywide gasoline quality standard will better reflect their unique operational needs. Here's why that's important. It's no secret that fuel economy has been one of the greatest driving forces of automotive evolution over the past several decades. As corporate average fuel economy (CAFE) standards have grown increasingly lofty, OEMs eke out new efficiencies from every area of the vehicle. One of those areas, of course, is the engine, and many OEMs have deployed gasoline direct injection (GDI) technology, which is becoming the most common engine technology on American roadways. But while GDI engines proliferate, varying fuel additization throughout North America has not necessarily kept pace with their unique needs and can, in fact, hinder those engines from meeting and sustaining their full fuel economy potential.
Blackburn, Brett
The U.S. auto industry might be getting “more than what they asked for” when it comes to slashing federal fuel economy regulations. That's a quote from Cox Automotive's director of industry insights, Stephanie Valdez Streaty, and reported by multiple outlets. This is a topic you'll find addressed in this month's Supplier Eye (page 6), but it's worth mentioning here just as one more marker in the sand of where things look like they are headed. On February 12th, the U.S. EPA rescinded the scientific finding that greenhouse gas emissions pose a threat to public health. As vehicles are a main source of GHGs, this finding allowed regulators to, well, regulate. The current White House discounts scientific findings it finds inconvenient, and has now weakened the EPA's power to regulate fuel economy standards. News reports say the administration is likely to reduce the current, agreed-to rules requiring 50.4 mpg (4.67 L/100km) new-vehicle fleet average by model year 2031 to just 34.5 mpg (6.82 L/100km).
Blanco, Sebastian
In recent years, the rapid growth of hybrid vehicles has driven the development of dedicated hybrid engines (DHEs) as a key powertrain technology for achieving high thermal efficiency and low emissions. Driven by stringent emissions regulations and demand for improved fuel economy, enhancing thermal efficiency in gasoline engines remains a critical industry challenge. Exhaust gas recirculation (EGR) technology dilutes oxygen in the intake charge, suppresses knock, and optimizes combustion phasing. However, excessive EGR rates compromise combustion stability by inducing elevated cyclic variability and potential misfire, posing challenges in maintaining stable combustion and improving fuel efficiency at high EGR levels. Thus, combustion stability and fuel efficiency optimization in Geely’s DHEs under high EGR conditions was investigated in this article. In this study, a high tumble combustion system was designed to enhance charge motion and promote stable flame propagation. Furthermore, exhaust gases were drawn from the upstream side of the three-way catalyst to realize high EGR rate. Additionally, high-energy ignition system was applied to ensure stable combustion under high EGR dilution conditions. Compared with the 1.5T engine with a similar technical route, the optimized DHE achieved a 5.4% increase in EGR rate and a 7.2 g/kWh reduction in brake specific fuel consumption (BSFC). These results demonstrate the feasibility of high EGR operation in gasoline engines through synergistic combustion system design and ignition enhancement, offering a scalable solution for meeting future fuel efficiency and emissions targets.
Li, QiangDeng, XiaorongRen, SimingZhang, PeiyiZhu, YunfengLi, HongzhouYan, PingtaoGu, Xiangsheng
The transportation system is one major catalyst to urban ecological imbalance. In developing countries, two-wheelers are considered a major mode of urban personal transportation because of their compactness, easy maneuver in heavy traffic and good fuel efficiency. In India, middle and lower middle-class people prefer to choose two wheelers, and these vehicles are dominantly fuelled by gasoline. Although, the energy consumption by a two-wheeler is comparatively less than that of a four-wheeler, they use about 60% of the nation’s petroleum for on-road vehicles and the impact on urban air quality and climatic change is significantly high. This high proportion of gasoline utilization and emission contribution by two wheelers in cities demand greater attention to improve urban air quality and near-term energy sustainability. Electrification of two-wheelers through the application of a plug-in hybrid idea is a promising solution. A plug-in hybrid motorbike was developed by putting forth a novel drive technique, which demonstrated the advantages of reducing greenhouse gas emissions and using less fuel. The experimental investigation reveals noticeable petroleum fuel savings and greenhouse emission reduction. Through the installation of a hub motor in the rear wheel, the dynamic behaviour of the prototype was examined and observed marginal changes in ride parameters. A cost-benefit analysis was also performed to estimate the payback period for the additional cost incurred.
Kannan, PrashanthShaik, AmjadTalluri, Srinivasa Rao
In commercial vehicles, conventional engine-driven hydraulic steering systems result in continuous energy consumption, contributing to parasitic losses and reduced overall powertrain efficiency. This study introduces an Electric Powered Hydraulic Steering (EPHS) system that decouples steering actuation from the engine and operates only on demand, thereby optimizing energy usage. Field trials conducted under loaded conditions demonstrated a 3–6% improvement in fuel economy, confirming the system’s effectiveness in real-world applications. A MATLAB-based simulation model was developed to replicate dynamic steering loads and vehicle operating conditions, with results closely aligning with field data, thereby validating the model’s predictive accuracy. The reduction in fuel consumption directly translates to lower CO₂ emissions, supporting regulatory compliance and sustainability goals, particularly in the context of tightening emission norms for commercial fleets. These findings position EPHS as a cost-effective and scalable solution for improving vehicle efficiency and environmental performance. Furthermore, the study highlights the future potential of transitioning to fully electric power steering systems (Full EPS), which not only promise additional efficiency gains but also enable seamless integration with Advanced Driver Assistance Systems (ADAS), laying the foundation for enhanced safety, automation, and intelligent vehicle control in next-generation commercial vehicles.
T, Aravind Muthu SuthanMani, KishoreAyyappan, RakshnaD, Senthil KumarS, Mathankumar
Carbon fiber-reinforced polymers (CFRPs) have become essential in modern aerospace structures, from fuselage skins and wing components to nacelles, interior structures, and a growing range of primary load-bearing parts. Their high strength-to-weight ratio delivers major benefits in fuel efficiency, payload capacity, and fatigue performance. Yet achieving reliable adhesive bonds on CFRP surfaces remains a persistent engineering challenge. The low intrinsic surface energy of composites - particularly under thermal cycling, vibration, and moisture exposure - limits bond durability unless surfaces are properly prepared. Plasma surface treatment has emerged as a pivotal solution, offering a fast, controllable, and non-destructive way to increase surface energy, improve wettability, and enhance adhesion across complex geometries. This is especially important as the aerospace industry transitions from thermoset to thermoplastic composites (TPCs), which enable faster processing, lower production costs, and better recyclability.
Composite materials have become widely adopted in commercial aviation, as aerospace manufacturers look to use them to drive weight reduction and improved fuel efficiency in new aircraft designs. In the case of aircraft rotary blades, the poor wear properties of these materials have necessitated the development of metal leading edge guards that can provide critical protection against erosion and impact damage during flight. Electroforming has been a leading process for the manufacture of these protective guards, with nickel parts providing excellent wear resistance that significantly extends the service life of the rotary blade assembly. Currently there has not been a focus on utilizing direct electrodeposition of metal on to carbon filled epoxy composite structures, as traditional plating-on-plastics approaches require considerable effort in surface preparation and normally do not provide adequate adhesion to the underlying structure. Alpha Metalcraft Group has been working in cooperation with aerospace suppliers in the design of an electroplating ready composite structure that would allow for direct nickel deposition, provide excellent adhesion, and significantly reduce both the time and cost for the manufacture of ready-to-assembly rotary blade structures. Test panels were constructed of commercially available prepreg materials or by resin infusion of dry fabrics that incorporated different metal containing conductive layers to allow for the direct deposition through a nickel sulfamate electrodeposition process. Different surface modification strategies were investigated to expose the metal conducting layer and thereby provide the metal-to-metal bonding surfaces required for successful electrodeposition.
Cazzaniga, Luigi
The automotive regulatory landscape in India is evolving rapidly, driven by a dynamic policy intervention by GOI, striking push for sustainable mobility, safety, technological advancements, dEnvironmentally soundeeper localization, energy self-reliance, product quality control and simplified registration process. Key regulations cover areas like vehicle safety norms, emission norms, fuel economy norms, BIS QCO, the promotion of EVs and alternative fuel vehicles, R & D roadmaps, ELVs, incentive policies and vehicle registration reforms. India has been keeping a close eye on the automotive regulatory progress in the Europe as well as other developed countries as a cornerstone for technical harmonization, cross learning, gauge benefits and economic implications. India is progressively aligning its automotive regulations with global standards, particularly with UN Regulations and GTRs, while also considering unique Indian driving and environmental conditions. This alignment is crucial for integrating into global value chains and enhancing India's competitiveness in the automotive sector. At the same time, GIO also has been taking the cognizance of ground realities regarding technological readiness, skilled workforce, supply chain resilience, infrastructure and cost competitiveness. Therefore, GOI always has been striking a balanced approach between harmonization of regulations and business implications (TCO, business sustenance and growth). This balancing act aims to foster a globally competitive automotive industry ensuring safety and environmental responsibility while nurturing the domestic market. This paper explores the various initiatives and policy reforms undertaken by GOI time to time in shaping India’s transition to a safe and sustainable mobility. This paper also upholds the commendable and remarkable actions accomplished collectively by GOI Ministries/Departments, Test agencies, OEMs for the stride towards the destination of safe and clean mobility. The regulatory information presented in the paper focuses on four and above wheeled vehicles and excludes 2/3-wheeled vehicles.
Patil, Dharmarayagouda
In the pursuit of environmental sustainability and cleaner transportation, the global automotive industry is expediting transformation. This paper utilized multi-decade data spanning from 1975 to 2024, for the development of predictive models for fuel economy and CO₂ emissions across a wide range of vehicle technologies from 2026 - 2050. This is done with the help of advanced machine learning algorithms like Linear and Random Forest Regression in Python and integrating insights through Power BI visualizations, the project identifies key correlations between vehicle attributes such as weight, powertrain, and footprint and their environmental performance. Results highlight the increasing impact of electric vehicle adoption, hybridization, and light weighting on overall emissions reduction. These insights help forecast the direction of fuel economy standards, emission patterns, and technology shifts across manufacturers and vehicle types. Beyond technical predictions, the study offers a decision-support framework for global policymakers, automotive designers, and sustainability advocates. The findings provide the importance of data-driven approaches that can increase regulatory compliance, influence the innovation process, and support sustainable mobility solutions on a global scale.
Hazra, SandipTangadpalliwar, SonaliHazra, Sanjana
Rising environmental concerns and stringent emissions norms are pushing automakers to adopt more sustainable technologies. There is no single perfect solution for any market and there are solutions ranging from biofuels, green hydrogen to electric vehicles. For Indian market, especially in the passenger car segment, hybrid vehicles are favoured when it comes to manufacturers as well as with consumer because of multiple reasons such as reliability, performance, fuel efficiency and lower long-term cost of ownership. For automakers planning to upgrade their fleets in the context of upcoming CAFE III (91.7 g CO2 / km) & CAFE IV (70 g CO2/km) norms, hybridization emerges as the next natural step for passenger cars. Lately, various state governments have also promoted hybrid vehicle sales by offering certain targeted tax breaks which were previously reserved for EVs exclusively. Current study focuses on various parallel hybrid topologies for an Indian compact SUV, which is the highest selling and fastest growing segment in India. The selected SUV with curb weight ~1255 kg has a 1.2 L turbocharged gasoline engine with peak power and peak torque of 88 kW and 170 Nm respectively. Simulations of various low voltage (LV) and high voltage (HV) hybrid topologies like P0 LV (base scenario for 2030), P0P2 LV, P0P2 HV and P0P4 HV are performed as per Worldwide Harmonized light vehicle Test Procedure (WLTP) in line with upcoming CAFE norms. Results are analysed to gauge performance (acceleration, gradeability) and fuel consumption. Regeneration and torque boosting capabilities of various hybrid topologies are also compared analytically based on simulation results. Gaussian optimization methodology is employed to systematically optimize powertrain configurations and control strategies to maximize fuel efficiency.
Warkhede, PawanKeizer, RubenSandhu, RoubleEmran, Ashraf
The globe is looking headlong to set up new benchmarks for the reduction of GHG (Green House Gases) considering short-term and long-term strategies. Efforts in the Internal Combustion Engines (ICE) domain have been accelerating to find an alternative way to reduce harmful emissions. Hydrogen is considered as a promising fuel to leapfrog this transition. Hydrogen fuel can be categorized into vast mobility areas viz. ICE and Fuel Cell Electric Vehicle (FCEV). Hydrogen fuel has attracted global attention from engine researchers due to the crude oil crisis and its rise in prices in recent years. This will serve the nation's goal towards carbon neutrality. Hydrogen has a few advantages such as less fueling time, higher heating value and more efficiency making it an eye-touching fuel for the automotive industry. In the contemporary FCEV segment, many fuel cell technologies have evolved, wherein the development of Proton Exchange Membrane (PEM) fuel cell technology has taken a new height for heavy-duty commercial vehicle applications due to its significant interest in the non-existent tailpipe CO2 emissions. Since electric vehicles are also being combined with hydrogen fuel and the opportunity persists to convert it into a hybrid system or FCEV. There is always a keen curiosity of the end user to know the mileage of a vehicle as a distinguishing measure of fuel economy. Thus, it is pertinent to determine the hydrogen fuel economy of the FCEV vehicle. This paper provides an insight into fuel cell fundamentals, the working principle of hydrogen fuel cell vehicles, vehicle operation modes and testing methodology to determine the fuel economy of FCEV based on the electric current method and pressure method. The vehicle (e-Bus) has been validated on a chassis dynamometer based on the prescribed DBDC Cycle in the AIS 049 standard to calculate the hydrogen fuel economy of the FCEV Bus. The multiple stacks of PEM fuel cells connected in series has been used along with the electric powertrain vehicle and estimation of its fuel economy are the focus of this paper.
Joshi, Ashish RajendraKandalgaonkar, SiddheshSontakke, Rushikesh
The automotive industry has been expediting progress toward electrification since climate change driven by global warming represents a significant environmental challenge with far-reaching implications. While electric vehicles offer considerable potential for mitigating CO₂ emissions, their elevated upfront costs pose a notable challenge to large-scale market penetration. Hybrid electric vehicles can serve as an effective intermediary solution, bridging the gap between conventional internal combustion engine vehicles and fully electric vehicles, owing to their comparatively lower initial costs. Hybrid electric vehicle component selection is a complex process that must fulfill multiple requirements: fuel economy, performance, drivability, packaging, total cost of ownership and comfort. Additionally, the selection of hybrid configuration also plays a vital role in determining the cost of the hybrid electric vehicle. Hence, it is a great challenge to select the right powertrain configuration, including architecture selection (P1, P2, P3 and P4), motor and overall gear ratio to achieve better overall performance compared to conventional vehicle constraints and targets. The present study investigates the principles guiding the selection of an electric drive system for hybrid electric vehicles in the heavy commercial vehicle segment. The analysis encompasses motor sizing, transmission configuration, and overall gear ratio optimization to meet defined vehicle-level performance targets. The automotive market in India is analyzed and the Heavy commercial vehicle segment selected to specify hybrid powertrain configuration. The principle is based on vehicle performance, design, cost and efficiency requirements. The simulation is done to estimate motor torque/power requirements & overall gear ratio meeting the vehicle target and constraints. Based on the analysis, a comparative matrix consisting of various parameters for heavy commercial vehicle (HCV) application is established. The analyzed results and comparative assessment indicate that
Shendge, RamanJadhav, VaibhavWani, KalpeshWarule, Prasad
More efficient drivetrain technologies are in greater demand in the two-wheeler market as a result of the introduction of BS6.2 emission standards. In order to satisfy these performance and regulatory requirements, Continuously Variable Transmission (CVT) systems, which are renowned for their stepless gear shifting and increased fuel efficiency, are being given more and more consideration. However, because CVT is nonlinear and multibody dynamic, accurately predicting its behavior is still a difficult task. With an emphasis on variables like belt slip, pulley misalignment, and transmission efficiency, this study provides a thorough multibody dynamic analysis of a belt-type CVT system used in two-wheelers. High-fidelity analysis of the belt-pulley interaction under various load and speed conditions is now possible thanks to the development of a novel modeling methodology The method makes early design validation easier, minimizes iterations of physical prototyping and helps to maximize system performance. This study supports the automotive industry's drive for affordable and emission-compliant vehicle development by offering a strong framework for virtual validation of CVT systems under actual operating conditions.
Shah, SwapnilMane, PrashantVoncken, AntoniusEmran, Ashraf
Modern automotive powertrains are increasingly adopting engine downsizing and down speeding to meet stringent emission regulations and improving fuel efficiency However, these changes result in higher torsional vibrations excitation amplitudes and NVH (Noise, Vibration, and Harshness) refinement more challenging. With growing customer expectations for premium driving experiences conventional clutch is no longer sufficient. To meet the NVH performance targets of the vehicle Dual Mass Flywheels (DMFs) are used In DMF due to lower stiffness and inertia separation there is a greater advantage on torsional filtration in normal drive and idle condition. But the torsional resonance frequency of the connected DMF is lower than the idle RPM. Engine startup is a key drawback with DMF equipped vehicles. The proper tuning of starter motor performance & DMF stiffness is required to cross the resonance zone faster otherwise it will lead to DMF to stay in the resonance zone for a longer time leading to structural failure over the period. In this paper we focus on DMF resonance crossing during engine startup condition in the 3 Cylinder Gasoline application. Test measurement is done to capture the startability behavior of DMF. AMESIM 1D simulation model is developed to reproduce the DMF resonance behavior and relative displacement between Primary and secondary flywheel is simulated. Optimization of DMF Spring stiffness between stages are proposed based on correlated simulation model. With the new design of DMF, the startability of the vehicle has improved & also the DMF displacement is reduced within the design limit. This evaluation method gives quick assessment on startability improvement in DMF equipped vehicles.
Jayachandran, Suresh KumarVijayaragavan, ThirupathiM, DevamanalanKanagaraj, PothirajAhire, ManojVellandi, Vikraman
Engine braking is a deceleration technique that leverages the internal friction and pumping losses within the engine. By closing the throttle and potentially selecting a lower gear, the engine creates a retarding force that slows the vehicle. This practice contributes to better fuel economy, decreased brake system load, and improved vehicle handling in specific driving scenarios, such as steep declines or slippery road surfaces. To alleviate stress on their primary braking systems and prevent overheating, heavy vehicles frequently incorporate engine-based braking. While older trucks relied on simple exhaust brakes with a butterfly valve to restrict exhaust flow, these had limited impact. Hence contemporary heavy vehicles almost exclusively use more advanced engine braking technologies. Traditionally, our heavy-duty vehicles use Exhaust brake system to elevate the braking performance on hilly terrains. Hence an improved sample of Engine brake was developed for enhanced braking performance. A study to map the performance of Engine braking at different field conditions was conducted at Chassis Dynamometer Lab on M&HCV Tipper Vehicle model. Conditions are: a) Different speeds/gears. b) Different gradients. Vehicle fitted with improved sample of Exhaust brake is tested on Chassis dyno for its performance. Braking power derived & plotted at various Engine speeds and compared with the performance results of existing Engine brake sample. Iterations carried out using various gears at different levels of gradient to simulate real world performance of Engine braking and tested the capabilities of the brake sample to the extreme levels of over speeding engine revolutions. The results obtained from this exercise fortified in evaluating and optimizing the improved sample of exhaust brake and it in turn aided in better performance of the vehicle on road.
M, Vipin PrakashRajappan, Dinesh KumarR, SureshN, Gopi Kannan
The CPCB-IV+ emission compliance for genset application is applicable with effect from 1st July 2023 as per as per GSR 804(E). The CPCB-II to CPCB-IV+ changeover in very stringent in emission front by almost 90 % emission reduction. It’s a significant advancement in environmentally sustainable powertrain technology. To meet the CPCB-IV+ Emission, combustion development & ATS technology plays an important role. First is the base engine need to optimize enough with combustion & associated parts. Second is the after treatment system which will carry the battle further to the engine emission with minimum margin of 10 % engineering target. This paper present the systematic approach followed to meet CPCB-IV+ emission norms for upgradation of 21 litre TCIC engine for the power range (56 < P ≤ 560). Here the challenge to avoid major changes in the existing CPCB-II FIE recipe & meet the CPCB-IV+ emission with ECU calibration & ATS system calibration with its potential. Here interesting parts unique communication architecture built with genset controller in leading role due to time line constraints. The engine integrates with advanced combustion strategies, improved fuel injections systems, and robust after treatment technology including DOC, DPF & SCR system to significantly reduce NOX, PM, HC & CO Emission. Phase-I (Base engine Calibration): - Baseline engine optimization with existing CPCB-II recipe & ECU calibration feature. Here we have used the 1600 bar rail pressure potential along with optimized fuel timing. The pilot & post injection strategy plays vital role to meet the targeted base engine emission. Phase-II (ATS system selection & its calibration): - To meet the CPCB-IV+ emission norms, stringent limits of NOX, PM introduces in India for genset application. For achieving this a highly optimized after treatment system (ATS) comprising DOC, DPF, SCR, and ASC is essential however our strict target is to avoid the DPF. These strategies collectively help to meet the CPCB-IV+ emission targets with optimum engine performance & fuel economy with potential of ATS architecture and a structured calibration methodology. The DOC enables rapid HC/CO oxidation, while the SCR system, controlled via open-loop urea dosing, achieves >95% NOx conversion. The ASC prevents ammonia slip beyond 10 ppm, ensuring exhaust pipe compliance. This project completed within very low stipulated time month effectively. Phase-III (OBD): - The OBD part of CPCB-IV+ contains the following Check on Torque Reduction & Shutdown Strategy Components wise diagnostic calibration on first proto Report on final diagnostic calibration Phase-IV (Engine Consistency & TA Certification):- Emission consistency trial.
Rane, VikasJagtap, ShaileshGothekar, SanjeevPawar, Narendra VKhedkar, PrasadKagade, SamadhanKendre, MahadevG Bhat, PrasannaThipse, S
The purpose of this research is to examine the fundamental principles of a circular economy (CE) in relation to the automotive industry in India, which plays a vital role in the country's economy. As a result, energy consumption and environmental impacts also pose significant challenges. CE provide a transformative approach through the life cycle of a vehicle, guiding the automotive industry toward a more sustainable transportation system. In order to decarbonize this industry, the global automotive commission recommends that recycled plastic content in vehicles be increased to 20-25% by 2030. This target necessitates the recovery of plastics from end-of-life vehicles, though these materials are rarely integrated into compounds today. The automotive industry's reliance on plastics has grown substantially due to their lightweight properties, which enhance fuel efficiency, reduce CO₂ emissions, and improve versatility and mechanical performance. polypropylene polymer and several other polyolefins are used for components like bumpers. The most prevalent recycling method for polypropylene bumpers is mechanical recycling, yet it presents notable challenges. It is important to note that paint, in particular, affects both the aesthetic quality and the structural integrity of recycled materials. This review work also explores the primary recycling methods documented in literature, particularly those that have minimal environmental impact. Further, the study provides a comprehensive analysis of India's transition toward sustainability in the automotive sector, including procedures for waste disposal and reuse. The report emphasizes the industry's growing pressure to adopt circular and sustainable approaches in production, vehicle design, and waste management while emphasizing the principles of reducing, reusing, and recycling plastic waste.
Kumar, Vijay Bhooshan
Overloading in vehicles, particularly trucks and city buses, poses a critical challenge in India, contributing to increased traffic accidents, economic losses, and infrastructural damage. This issue stems from excessive loads that compromise vehicle stability, reduce braking efficiency, accelerate tire wear, and heighten the risk of catastrophic failures. To address this, we propose an intelligent overloading control and warning system that integrates load-sensing technology with real-time corrective measures. The system employs precision load sensors (e.g., air below deflection monitoring via pressure sensors) to measure vehicle weight dynamically. When the load exceeds predefined thresholds, the system triggers a multi-stage response: 1 Visual/Audio Warning – Alerts the driver to take corrective action. 2 Braking Intervention – If ignored, the braking applied, immobilizing the vehicle until the load is reduced. Experimental validation involved ten iterative tests to map deflection-to-voltage relationships, confirming linearity in load detection. System modelling in MATLAB demonstrated consistent linear responses in load-deflection-voltage interactions, proving theoretical efficacy. A Proteus-based simulation further validated the system’s operational logic. Key Contributions Preventive Safety Mechanism – Proactively restricts vehicle operation under unsafe loads. Regulatory Compliance – Ensures adherence to legal weight limits. Economic & Infrastructural Benefits – Reduces maintenance costs and road wear.
Raj, AmriteshPujari, SachinLondhe, MaheshShirke, SumeetShinde, Akshay
The present work demonstrates a transient Fluid-Structure-Interaction (FSI) based numerical methodology for estimation of aerodynamic-induced flutter of the rear bumper of a Sports Utility Vehicle (SUV). Finite Volume Method (FVM) based High-fidelity transient full vehicle aerodynamic simulations were conducted for the estimation of the transient aerodynamic load. Subsequently, by mapping this transient aero load onto the surface of the rear bumper, Finite Element Method (FEM) based dynamic structural simulations were performed to predict its response. The results obtained through simulations were then compared against experimental wind tunnel test data of a prototype car with modified bumper for the specific test-case. The pressure and the time series data of rear bumper deflection were captured at multiple probe locations from wind tunnel experiments at 140 and 200 kmph. The distribution of pressure on the rear surfaces of the car was well captured by the aerodynamic simulation at both speeds. The deflection amplitude and patterns across multiple probe locations and across the two speeds were reproduced with reasonable accuracy by the methodology.
Choudhury, SatyajitYenugu, SrinivasaWalia, RajatZander, DanielGullapalli, AtchyutBalan, ArunAstik, Pritesh
In line with global peers (EU, Japan, etc.), the Automotive Industry Standard (AIS) Committee in India has decided to adopt “World harmonized Light vehicle Test Procedure (WLTP)” for M2 and N1 category vehicles not exceeding 3500 kg and for all M1 category vehicles. As a result, “World harmonized Light-duty vehicles Test Cycle (WLTC)” is set to replace currently applicable “Modified Indian Drive Cycle (MIDC)” in the next couple of years. The draft Corporate Average Fuel Economy (CAFE) III & CAFE IV norms for CO2 emission limits, which are set to be implemented in year 2027 and 2032 respectively refer to a shift to WLTP from MIDC. The latest draft of Central Motor Vehicle Rules (CMVR) for BS-VI emissions is also being revised to use WLTC as test cycle. This migration to WLTC is in sync with the demand for test procedures to replicate real driving conditions more appropriately. Further, the move to WLTC along with stricter emission norms is a major step towards realizing India’s COP26 pledge to achieve net zero emissions by 2070. WLTC being much more dynamic with higher average speeds and acceleration compared to MIDC, has a major impact on the vehicle CO2 emission. Other gaseous pollutants like NOx also increase significantly with WLTC. This study takes into consideration the impact of change in test procedure on a conventional small commercial vehicle. Using the well validated models from FEV, simulations are performed to quantify the differences in various gaseous emissions under both MIDC and WLTC as well as under a typical Indian Real Driving Emissions (RDE) cycle with base calibration. Further, a step wise approach is detailed to have vehicles compliant with upcoming norms. The methodology lists both basic measures like calibration and hardware upgrades (e.g., change in injection pressure) as well as advanced measures including deploying additional technologies like advanced aftertreatment systems and hybridization etc. to improve fuel efficiency as well as reduce tail pipe emissions.
Pawar, BhushanEhrly, MarkusSandhu, RoubleEmran, AshrafBerry, Sushil
With introduction of Corporate Average Fuel Efficiency norms (hereafter referred as CAFÉ norms) in India, the manufacturers of all M1 Category vehicles (not exceeding 3,500kg GVW) must ensure that they comply with Annual Corporate average CO2 target as defined in regulation. Moreover, this target will become stricter at various stages in the coming years. Hence CO2 emissions are becoming one of the major focus parameters during vehicle development. There are several factors that can impact CO2 emissions during measurement in laboratory-based test cycles such as MIDC or WLTC. One such major factor is driving variations. Although speed and time tolerances are provided during the test (as part of AIS 137/AIS 175) to limit the variation, even within these tolerances, drive-related effects make significant contribution to test results variability. Monitoring and control of such variations is important to understand the true fuel economy potential of the vehicle. Drive Trace indices are standardized metrics that can be used to evaluate the driving variations. The aim of this study is to understand the different driving behaviors on drive indices and consequently on CO2. Drive indices such as Energy Rating (ER), Distance Rating (DR), Energy Economy Rating (EER), IWR (Inertial Work Rating), RMSSE (Root Mean Square Speed Error) defined in SAE J2951 document have been referred for this study. Multiple MIDC & WLTC emission test data have been used for evaluation of driving behavior. An attempt has been made to establish a correlation between the drive trace indices and CO2 (and fuel economy) in MIDC by using mathematical techniques similar to study done by JRC for WLTC.
ER, ShivramRawat, VijaypalKhandelwal, VineetKumar, ArunMalhotra, Jitendra
In alignment with its carbon reduction commitments, India is transitioning towards higher ethanol-blended fuels, with E20 set for nationwide implementation by 2025. Ethanol is a renewable, domestically produced biofuel produced through fermentation of biomass such as sugarcane, corn. It possesses a higher octane rating and oxygen content compared to conventional gasoline, making it a favorable additive for improving engine performance and reducing emissions. This study investigates the impact of E20 fuel on performance parameters of a 694 cc MPFI , water-cooled, twin-cylinder gasoline engine. For deriving maximum benefits of increased Octane rating of E20, compression ratio was increased to 12.5:1. Experimental analysis was conducted to assess the changes in combustion behavior, brake specific fuel consumption (BSFC), torque output, engine out emissions and thermal efficiency when operating on E20 compared to baseline gasoline (E10). Base results indicate that E20 promotes more efficient combustion, owing to its higher laminar flame speed and elevated oxygen content, leading to a 3–4% improvement in low-end torque across real-world operating speed ranges. Conversely, on-road evaluations reveal a 3–4% fuel economy penalty with E20 relative to E10. Recovering E10-comparable fuel efficiency with E20 necessitates comprehensive engine calibration optimization, supported by targeted hardware modifications. Additionally, the high octane rating of ethanol reduces knock propensity, enabling the adoption of more aggressive ignition timing and higher compression ratios without compromising engine durability. Thermal benefits are also taken into consideration, with a reduction in peak mid-catalyst temperatures by approximately 30–40°C, this enables stoichiometric operation throughout operating range without any enrichment. These improvements suggest that engines calibrated specifically for E20 can be benefited through fuel’s inherent properties to achieve higher thermal efficiency and lower tailpipe emissions. In conclusion, the incorporation of E20 fuel in internal combustion engines shows notable advancements in engine performance and efficiency.
Kulkarni, DeepakMalekar, Hemant AThonge, RavindraKanchan, Shubham
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