Hybrid Solar Vehicles Research Articles

Heavy-duty vehicles with solar panels as a regenerative power source

Abstract Road transportation represents more than a third of all CO2-producing sources on Earth, being the main producer of greenhouse gas (GHG) emissions. Nowadays, continuous development of technology has reduced fossil-fuel consumption by integrating clean energy sources as a range extender. Solar energy has the largest potential of all renewable energy sources worldwide. The photovoltaic and energy storage research fields have grown exponentially during the last decade and, forced by the current energy crisis, had a great contribution to the hybrid solar vehicles (HSV) industry. Vehicle Integrated Photovoltaics (VIPV) comply with requirements on vehicles aesthetics, and they convert solar energy into electric energy to supply the low-voltage and high-voltage battery packs onboard HSV. Heavy-load road transportation by commercial vehicles equipped with PV-integrated modules or retrofit installation will contribute to global decarbonization. A study is done on a configuration of a heavy-duty vehicle with its cuboid cargo body covered with solar panels and a regulated driving route during different weather conditions [3]. The energy management system is designed to maximize solar energy conversion in order to reduce fuel consumption and extend the vehicle’s total driving distance.

Energy Management System in Series-Parallel Hybrid Solar Vehicle

In this paper, the study on energy management in a hybrid solar vehicle is presented. The proposed system consisted of five main energy conversion components i.e. internal combustion engine, electric motor, electric generator, battery, and photovoltaic. The energy management system in hybrid solar vehicles aims to select the best mode of operation corresponding to the driving conditions and the state of charge of the battery. In this study, the proposed energy management system applied a specific energy balance equation for each mode of operation of the vehicle as the basis of the decision-making algorithms. The algorithms are then simulated on a model of series-parallel hybrid solar vehicle system to investigate the power supplied by each component, the fuel consumption of the vehicle, and the efficiency of each component. The results show that the fuel consumption of an internal combustion engine on a hybrid solar vehicle is about 30% less than the conventional vehicle, in which up to 0.6 % contributed by the photovoltaic cells.

Fuzzy Logic-Based Novel Hybrid Fuel Framework for Modern Vehicles

The transport sector has proven to be the largest contributor to global CO 2 emissions. To reduce CO 2 emissions and improve mileage, the existing research has proposed different fuel models for vehicles such as Plug-in Hybrid Electric Vehicles (PHEVs), Electric Vehicles (EVs), solar and hydrogen Vehicles. However, these vehicles suffer from a range of issues and solutions are required to increase range, and improve charging. In this context, we propose A Novel Hybrid Fuel Framework for Modern Vehicles, to reduce CO 2 emissions and increase vehicle mileage, by managing energy resources efficiently through the application of Fuzzy Logic. It considers three different energy sources i.e., gasoline, solar and electric power, to charge a vehicle, and suggest a modification in the architecture of EVs is made for the availability of all these energy resources. We use Visual Studio to implement fuzzy logic based algorithm designed to simulate the proposed system and added a small gasoline engine to the existing architecture of EVs to provide energy resources that overcome charging issues during long-range travel. We use the Statistical Package for Social Sciences (SPSS) tool to evaluate the performance of the proposed framework for CO 2 emissions and fuel efficiency. The proposed framework achieves the best mileage of 57.6 Kilometers per liter (Km/l) with a 660 Cubic Centimeter (CC) gasoline engine which is 111.11% more efficient than existing frameworks. Moreover, CO 2 emissions through our proposed framework are 41.52 Grams per Kilometer (G/Km) which are 53% lower than current frameworks. The proposed framework also improves the charging duration of batteries i.e., a 10 Kilowatt-Hour (KwH) battery can be charged in 1 hour and 15 minutes.

Converting a Conventional Car into a Hybrid Solar Vehicle: a LCA Approach

The growth of world energy consumption and the increase of passenger vehicles areis setting new challenges to environmental protection. Large diffusion of electric vehicles and hybrid electric vehicles seems to be the most feasible solution. However, the need of fast charging infrastructure, the still low penetration of renewable electricity production and the massive reconversion of fleets limit the feasibility of this solution.A life-cycle assessment study of several mobility options is presented in the paper. The analyses, performed by the use of the GREET model software, show that a suitable solution to reduction of total energy consumption and greenhouse gases emissions in the short to medium term could be the conversion of conventional vehicles into hybrid solar vehicles, as in the system developed at the University of Salerno.

Impacts of Adding Photovoltaic Solar System On-Board to Internal Combustion Engine Vehicles Towards Meeting 2025 Fuel Economy CAFE Standards

The challenge of meeting the Corporate Average Fuel Economy (CAFE) standards of 2025 has led to major developments in thetransportation sector, among which is the attempt to utilize clean energy sources. To date, use of solar energy as an auxiliary source ofon-board fuel has not been extensively investigated. This paper is the first study at undertaking a comprehensive analysis of using solarenergy on-board by means of photovoltaic (PV) technologies to enhance automotive fuel economies, extend driving ranges, reducegreenhouse gas (GHG) emissions, and ensure better economic value of internal combustion engine (ICE) -based vehicles to meet CAFEstandards though 2025. This paper details and compares various aspects of hybrid solar electric vehicles with conventional ICE vehicles.Different driving locations, vehicle sizes, various driving patterns and different cost scenarios are used in order to enhance the currentunderstanding of the applicability and effectiveness of using on-board PV modules in individual automobiles and ensure an accuraterepresentation of driving conditions in all U.S states at any time. These times and location-dependent results obtained over a year show anincrease in the combined mile per gallon (MPG) at noon in the range of 2.9-9.5% for a vehicle similar to a Tesla S, and a significantincrease in the range of 10.7-42.2% for lightweight and aerodynamic efficient vehicles. In addition, by adding on-board PVs to cover lessthan 50% of the projected horizontal surface area of a typical mid-size vehicle (e.g., Toyota Camry or Nissan Leaf), up to 50% of totaldaily miles traveled by an average U.S. person could be driven by solar energy. Also, the return on investment (ROI) of adding PVson-board with ICE vehicle over its lifetime shows only negative values when the price of gasoline remains below $4.0 per gallon and thevehicle is driven in low-solar energy area (e.g., Boston, MA). The same ROI is more than 250% if the vehicle is driven in high-solarenergy area (e.g., Arizona), even if the gasoline price remains low. For future price scenarios, this ROI is much higher - nearly 10 times theinvestment cost under some scenarios, with the assumption of an eventual decline in battery costs. With regard to environmental impacts,significant gasoline gallons savings (~500-3400) and CO2 emission reduction (~5.0 to 34.0 short tons) are achieved.

Development of a regenerative braking control strategy for hybridized solar vehicle

This paper focuses on the development of a braking control strategy that allows the best tradeoff between mechanical and regenerative braking on a hybridized vehicle. The research work is part of a project for the development of an automotive hybridization kit aimed at converting conventional cars into Through The Road hybrid solar vehicles. The main aspect of the project is the integration of state-of-the-art components (i.e. in-wheel motors, photovoltaic panels, batteries) with the development of an optimal controller for power management. A mild parallel hybrid structure is obtained by substituting/integrating the rear wheels with in-wheel motors and adding photovoltaic panels and a lithium-ion battery. A hybridizing equipment prototype, patented by the University of Salerno, is installed on a FIAT Grande Punto. A model useful for real-time braking control has been developed, starting from vehicle longitudinal model and considering dynamic weight distribution in front and rear axles and related wheel slipping effects. Different braking strategies have then been investigated, in order to maximize the benefits of regenerative braking.

A Prototype Mild-solar-Hybridization Kit: Design and Challenges

This paper deals with the development of an automotive hybridization kit (equipment, along with associated techniques and methodologies), aimed at converting conventional cars into hybrid solar vehicles (Mild-Solar-Hybrid). The main aspect of the projects consists into the integration of state-of-the-art components (in-wheel motors, photovoltaic panels, batteries), and into the development of an optimal controller for the power management.A prototype of the hybridizing equipment – patented by the University of Salerno (Italy)- is installed on a FIAT Grande Punto. A mild parallel hybrid structure is obtained by substituting/integrating the rear wheels with 7kW in-wheel motors and adding a lithium battery to manage on-board energy. Thus, the vehicle can operate in electric mode (when ICE is switched off or disconnected by the front wheels) or in hybrid mode (when the ICE drives the front wheels and the rear in-wheel motors operate in traction mode or in generation mode, corresponding to a positive or negative torque). The battery can be recharged both by rear wheels, when operating in generation mode, and by photovoltaic panels.The vehicle is also equipped with an EOBD gate (On Board Diagnostics protocol), which allows accessing data such as pedal position, vehicle speed, engine speed, manifold pressure and other variables. The Vehicle Management Unit (VMU), which is part of the invention and implements control logics compatible with typical drive styles of conventional-car users, receives the data from OBD gate, from battery (SOC estimation) and drives in-wheel motors by properly acting on the electric node.The paper, focused on the main aspects of prototype design and realization, also provides insights on control issues related to the integration of the above-mentioned components, drivability and safety.

Converting Conventional Cars in Mild Hybrid Solar Vehicles

AbstractHybrid electric vehicles (HEV) represent a good and feasible solution to reduce fuel consumption and related emissions. Furthermore, there is an increasing interest toward the integration of HEV's with photovoltaic (PV) panels, in order to enhance their benefits. But, despite the recent commercial success of HEVs, their market share is still insufficient to produce a significant impact on global energy consumption. Moreover, due to the present crisis, a substantial substitution of conventional vehicles with HEVs is unlikely, at least in short time. Consequently, a realistic strategy could consist in developing solutions able to achieve part of the benefits of hybrid and solar vehicles on conventional vehicles. A method for the mild solar hybridization of conventional vehicles is presented in this paper, based on use of in-wheel motors on rear wheels, of a PV panels, of an additional battery and of control system not interfering with the original ECU. A preliminary assessment of the benefits obtainable in terms of fuel consumption as a function of the degree of mild hybridization is performed by simulation analysis.

Automotive Applications of Solar Energy

There is an increasing awareness about the need to achieve a more sustainable mobility, both among specialists and in public opinion, and about the opportunities given by renewable sources. In last years, increasing efforts are being spent towards the application of solar energy to electric and hybrid cars, also thanks to the advances in photovoltaic technology and to their growing diffusion for stationary plants. Anyway, the possibility to apply solar energy to cars is still considered as a questionable issue in the automotive community. In this paper, a survey study on the past, present and future applications of solar energy to cars is presented and the main issues are discussed, also on the base of the research performed by the author on Hybrid Solar Vehicles.

Introducing Sunshine Forecast to Improve On-Board Energy Management of Hybrid Solar Vehicles

Management strategies of Hybrid Solar Vehicles differ from Hybrid Electric Vehicles, which usually adopt charge sustaining strategies, because the battery can be recharged also during parking time by solar energy. Therefore, at the end of driving the final state of charge (SOC) is required to be low enough to allow full storage of solar energy captured in the next parking phase, whereas the adoption of an unnecessary constantly-low value of final SOC would give additional energy losses and compromise battery lifetime. The effects of different strategies of selection of final SOC are studied by simulation over hourly solar data at different months, and the benefits achievable by estimating the energy expected in next parking phase are assessed.

Effects of engine thermal transients on the energy management of series hybrid solar vehicles

The paper focuses on investigating thermal-transients effects, associated to intermittent use of internal combustion engine (ICE), on fuel economy and hydrocarbon (HC) emissions of series hybrid solar vehicles (HSVs). An offline, non-linear constrained optimization is set-up to individuate the ICE power trajectory that simultaneously minimizes fuel consumption, suitably operates the battery and fully exploits daily solar contribution. The results highlight the importance of including thermal transients in HSV energy management. The combined effects of engine, generator and battery losses, along with cranking energy and thermal transients, produce non-trivial solutions for the engine/generator group, which should not necessarily operate at its maximum efficiency.

On the Use of Genetic Algorithm to Optimize the On-board Energy Management of a Hybrid Solar Vehicle

This paper deals with the development of a prototype of Hybrid Solar Vehicle (HSV) with series structure. This activity has been also conducted in the framework of the European Union funded Leonardo project “Energy Conversion Systems and Their Environmental Impact”, a project with research and educational objectives. A study on supervisory control for hybrid solar vehicles and some preliminary tests performed on the road are presented. Previous results obtained by a model for HSV optimal design have confirmed the relevant benefits of such vehicles with respect to conventional cars in case of intermittent use in urban driving (city-car), and that economical feasibility could be achieved in a near future. Due to the series-powertrain adopted for the HSV prototype, an intermittent use of the ICE (Internal Combustion Engine) powering the electric generator is possible, thus avoiding part-load low-efficient engine operations. The best ICE power trajectory is determined via genetic algorithm optimization accounting for fuel mileage as well as battery state of charge, also considering solar contribution during parking mode. The experimental set up used for data logging, real-time monitoring and control of the prototype is also presented, and the results obtained with different road tests discussed.

Rule-Based Optimization of Intermittent ICE Scheduling on a Hybrid Solar Vehicle

ABSTRACT In the paper, a rule-based (RB) control strategy is proposed to optimize on-board energy management on a Hybrid Solar Vehicle (HSV) with series structure. Previous studies have shown the promising benefits of such vehicles in urban driving in terms of fuel economy and carbon dioxide reduction, and that economic feasibility could be achieved in a near future. The control architecture consists of two main loops: one external, which determines final battery state of charge (SOC) as function of expected solar contribution during next parking phase, and the second internal, whose aim is to define optimal ICE-EG power trajectory and SOC oscillation around the final value, as addressed by the first loop. In order to maximize the fuel savings achievable by a series architecture, an intermittent ICE scheduling is adopted for HSV. Therefore, the second loop yields the average power at which the ICE is operated as function of the average values of traction power demand and solar power. Expected solar contribution can be estimated starting from widely available solar databases and by processing past solar energy data measured on the vehicle. Neural Networks predictors, previously stored data and/or GPS derived information are suitable to estimate average power requested for vehicle traction. Extensive simulation analyses were carried out to test the performance of the RB algorithm, also comparing it to Genetic Algorithms-based optimization strategies previously developed by the authors. The results confirm the high potentialities offered by the proposed RB control strategy to perform real-time energy management on hybrid solar vehicles. The proposed rule-based optimization is currently under-implementation in an NI® cRIO control unit, thus allowing to perform experimental tests on a real HSV prototype developed at University of Salerno.

Analysis of a Rule-Based Control Strategy for On-Board Energy Management of Hybrid Solar Vehicles

In the paper, the performances of a rule-based (RB) control strategy for a series Hybrid Solar Vehicle (HSV) are assessed via comparison with a batch genetic algorithm-based (GA) optimization. The RB strategy relies on heuristic rules defined by optimizing ICE start&stop strategy as function of average traction power and current solar irradiation. The comparison with the reference GA benchmark confirms the suitability of the proposed RB strategy for HSV on-board energy management. Extensive simulations were performed to test the influence of driving cycle features, power-prediction time-horizon and solar irradiation on HSV fuel economy. Such simulation analysis, beyond providing useful indications about correct implementation of the RB strategy, also demonstrates the potentialities offered by HSV powertrains in both urban and highway driving conditions.