1,720,963 research outputs found
DEVELOPMENT OF A STOP & START SAILING STRATEGY FOR NEXT GENERATION POWERTRAINS
No full textNowadays OEMs (Original Equipment Manufacturer) are facing the challenge of producing vehicles that meet future fuel economy and emissions requirements at an affordable price to satisfy the desired customer value. Stop & Start (S&S) system has been favourably accepted by OEMs lately, as it offers significant fuel economy improvements at minimal cost. S&S system removes the engine’s drag torque, when no traction is required, preventing from burning extra fuel. According to upcoming homologation cycles and due to more stringent CAFE (Corporate Average Fuel Economy) targets, S&S should be further improved, by operating it even with vehicle in motion. This new operating mode is known as Sailing: it decouples the engine from the driveline during coasting, extending the distance covered by the vehicle, and shutting the engine off. The automation of transmissions paves the way to the introduction of this feature. Consequently, the aim of this work is the definition of the main characteristics of this new feature and its evaluation: in order to assess the benefits of the sailing feature over real-driving conditions, an innovative control strategy has been developed and implemented into a simulation tool for the preliminary quantification of the benefits. Starting from the lesson learned numerically a prototype vehicle has been built and implemented with a proper logic for the autonomous management of the clutch during the activation of the feature.
Then, through an experimental test campaign on a C-segment vehicle powered by mid-sized EU6 diesel engine, the fuel economy potential and the impact on diesel emissions of S&S Sailing over real-world driving cycles, has been quantified. Finally a clinic survey was performed in order to study the phenomenon with normal drivers and investigate the level of acceptance of the actual prototype vehicle
Development of an optimal strategy for the energy management of a rangeextended electric vehicle with additional noise, vibration and harshness constraints
No full textNowadays, electric vehicles represent a promising solution for reducing the fuel consumption (and thus the carbon dioxide emission) and the pollutant emissions of road vehicles, especially in highly congested urban areas, although their driving range and usability still limit the customer acceptance even for a city car application. Extended-range electric vehicles may partly overcome these limitations, having an auxiliary power unit which can provide electrical energy to the powertrain once the battery has been depleted. On the other hand, the operations of such an auxiliary power unit should be almost completely unnoticeable in order to avoid any impacts on the electric driving experience, resulting in considerably reduced drive-related noise. Therefore the aim of this work is the design, through numerical simulation, of a powertrain controller capable of minimizing the carbon dioxide emission of a range-extended electric vehicle and, at the same time, avoiding any discomfort for the passenger related to the auxiliary power unit operations. Starting from the development of a powertrain controller focused on minimization of the carbon dioxide emission of the vehicle, the main noise targets will be defined and their effects on the energy management system will be analyse
Optimizing the design of a plug-in hybrid electric vehicle from the early phase: an advanced sizing methodology
Full text linkDevelopment of a new hybrid bus for urban public transportation
Full text linkNowadays the increasing demand for sustainable mobility has fostered the introduction of innovativepropulsion systems also in the public transport sector in order to achieve a significant reduction of pol-lutant emissions in highly congested urban areas. This paper describes both the design and the optimiza-tion of an environmentally friendly hybrid bus (hereafter referred to as ‘‘HYBUS’’) for urban publictransportation.After a preliminary description of the main features of the hybrid architecture, this paper assessed,through numerical simulations, the fuel economy potential of the hybridization in real world driving con-ditions. The promising results of this first part of the study led to the development of a first prototype.The first prototype of the bus was built by integrating an innovative hybrid propulsion system featuringa plug-in series architecture into the chassis of an old IVECO 490 TURBOCITY. The bus is 12 m long andcapable to host up to 116 passengers in the original layout. The project relied on a modular approachwhere the powertrain could be easily customized for size and power, depending on the specific applica-tion.The prototype was then extensively tested in the city of Genoa, Italy, an urban context extremelychallenging for a hybrid powertrain due to its frequent uphill routes and significant road grades. The out-comes of the test campaign confirmed the simulations forecasts, and fostered additional analysis aimedto optimize the energy management strategy of the hybrid powertrain.Numerical simulations were then used in order to identify more refined energy management strategiescapable of further enhancing the fuel economy potential of the hybrid architecture. Consequently, a novelenergy management was developed, and virtually tested, to manage the HYBUS in a more effective way.The results demonstrated the interesting potential of such hybrid architectur
Development of a Stop & Start Sailing Activation Strategy for a Real-World Driving
No full textStop and Start (S&S) systems have been favorably accepted by OEMs lately as they offer significant fuel economy improvements at minimal cost. According to upcoming homologation cycles and due to more stringent Corporate Aggregate Fuel Economy (CAFE) targets, S&S should be further improved by operating it also at vehicle in motion. This feature is known as Sailing: it decouples the engine from the driveline during coasting, extending the distance covered by the vehicle, and shuts the engine off. The automation of transmissions paves the way for the introduction of this feature.
In order to evaluate the opportunity for a sailing event over real-driving conditions, an innovative control strategy has been developed and assessed. This paper assesses, through numerical simulations and experimental testing on a C-segment vehicle powered by mid-sized EU6 diesel engine, the fuel economy potential of S&S Sailing over several schedules, i.e. FTP-75, US06, WLTP, Real Driving Emission (RDE). The simulation and experimental data over the new WLTP cycle highlight significant fuel economy benefits without significant engine emission drawbacks
Real CO2 emissions benefits and end user's operating costs of a plug-in Hybrid Electric Vehicle
Full text linkAlthough plug-in Hybrid Electric Vehicles (pHEVs) can be considered a powerful technology to promote the change from conventional mobility to e-mobility, their real benefits, in terms of CO2 emissions, depend to a great extent on the average efficiency of their Internal Combustion Engine and on the energy source mix which is used to supply the electrical demand of pHEV. Furthermore the operating cost of the vehicle should also be taken into account in the design process, since it represents the main driver in the customer's choice. This article has the purpose of assessing, through numerical simulations, the effects of different technology mixes used to produce electrical energy for the battery recharging, of different Internal Combustion Engines on the pHEV performance, and highlighting the main differences with respect to the regulatory test procedur
Analysis of Different Energy Management Strategies for Complex Hybrid Electric Vehicles
No full textThe performance of Hybrid Electric Vehicles (HEVs) is strongly affected by their powertrain control strategies, in particular when complex architectures are concerned. Therefore the purpose of this paper is to analyze, through numerical simulation, different methodologies to develop an energy management strategy aiming to minimize the overall CO2 emissions of the vehicle. In order to perform a comprehensive comparison, different optimization algorithms were selected among the available solutions in the control theory. Foremost a global optimization strategy, the Dynamic Programming (DP), was used to benchmark the performance of the energy management systems. Then a local optimization strategy, the Equivalent Consumption Minimization Strategy (ECMS), was evaluated, to prove its suboptimal performance and to evaluate the possibility to be implemented on a real Engine Control Unit (ECU). Finally, the potential of heuristic control techniques was evaluated due to their low computational requirements and since they represent the most common solution in real applications.
The analysis focused on the case study architecture of the Chevrolet Volt, for which a Simulink model was built and tested on both regulatory driving cycles and real world driving conditions, emphasizing pro and cons of each method
HYBUS: A New Hybrid Bus for Urban Public Transportation
No full textNowadays the increasing demand for sustainable mobility has fostered the introduction of innovative propulsion systems also in the public transport sector in order to achieve a significant reduction of pollutant emissions in highly congested urban areas. Within this context this paper describes the development of the HYBUS, an environmental friendly hybrid bus for on-road urban transportation, which was jointly carried out by Pininfarina and Politecnico di Torino in the framework of the AMPERE project. The first prototype of the bus was built by integrating an innovative hybrid propulsion system featuring a plug-in series architecture into the chassis of an old IVECO 490 TURBOCITY. The bus is 12 meters long and has a capacity of up to 116 passengers in the original layout. The project relied on a modular approach where the powertrain could be easily customized for size and power depending on the specific application. Furthermore this flexibility could pave the way to a significant reduction of investment costs since it could allow the revamping of obsolete vehicles in the fleet of public transportation companies, extending their end of life. After a preliminary description of the main features of the hybrid architecture, the paper assesses, through numerical simulations, the fuel economy potential of the vehicle in real world driving conditions. The promising results of this study led to the development of the abovementioned prototype which was extensively tested in the city of Genoa, Italy, an urban context which is extremely demanding because of its routes featuring a continuously variable altitude and significant grades. The experimental data collected during the test campaign confirmed the simulations forecasts, highlighting significant fuel economy benefits
Real World Operation of a Complex Plug-in Hybrid Electric Vehicle: Analysis of Its CO2 Emissions and Operating Costs
Full text linkPlug-in hybrid electric vehicles (pHEVs) could represent the stepping stone to move towards a more sustainable mobility and combine the benefits of electric powertrains with the high range capability of conventional vehicles. Nevertheless, despite the huge potential in terms of CO2 emissions reduction, the performance of such vehicles has to be deeply investigated in real world driving conditions considering also the CO2 production related to battery recharge which, on the contrary, is currently only partially considered by the European regulation to foster the diffusion of pHEVs. Therefore, this paper aims to assess, through numerical simulation, the real performance of a test case pHEV, the energy management system (EMS) of which is targeted to the minimization of its overall CO2 emissions. The paper highlights, at the same time, the relevance of the CO2 production related to the battery recharge from the power grid. Different technologies mixes used to produce the electricity required for the battery recharge are also taken into account in order to assess the influence of this parameter on the vehicle CO2 emissions. Finally, since the operating cost still represents the main driver in orienting the customer’s choice, an alternative approach for the EMS, targeted to the minimization of this variable, is also analyzed
Experimental Validation of Stop & Start Sailing Strategy for Real-world Driving Cycles
No full textNowadays OEMs are facing the challenge of producing vehicles that meet future fuel economy and emissions requirements at an affordable price to satisfy the desired customer value. Stop and start system has been favourably accepted by OEMs lately, as it offers significant fuel economy improvements at minimal cost.
S&S system removes the engine’s drag torque, when no traction is required, preventing from burning extra fuel. According to upcoming homologation cycles and due to more stringent CAFE targets, S&S should be further improved, by operating it even with vehicle in motion. This new operating mode is known as Sailing: it decouples the engine from the driveline during coasting, extending the distance covered by the vehicle, and shutting the engine off. The automation of transmissions paves the way to the introduction of this feature.
In order to assess the benefits of the sailing feature over real-driving conditions, an innovative control strategy has been developed and assessed. The paper evaluates, through an experimental test campaign on a C-segment vehicle powered by mid-sized EU6 diesel engine, the fuel economy potential and the impact on diesel emissions of S&S Sailing over real-world driving cycles, i.e. WLTP and Real Drive Emission. A “Design for Six Sigma” approach has been used to identify the optimal trade-off between frequency and duration of sailing events. The data collected over the new WLTP cycle highlight significant fuel economy benefits without any significant engine emission drawbacks
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