World Electr. Veh. J., Volume 6, Issue 2 (June 2013) – 26 articles , Pages 245-483

The powertrain control strategy and component sizing can significantly influence the vehicle performance, cost and fuel economy. This paper presents an evaluation study of the current and future Fuel Cell Hybrid Vehicles (FCHEVs) powertrains from the point of view of the fuel economy, volume, mass and cost. In this research, different FCHEV powertrains (such as Fuel Cell/Supercapacitor (FC/SC), Fuel Cell/Battery (FC/B), and FC/SC/B) and different control strategies are designed and simulated by using Matlab/Simulink. In this paper, two standard driving cycles (NEDC and FTP75) are used to evaluate the fuel consumption. Within this study, two control strategies based on the knowledge of the fuel cell efficiency map are implemented to minimize the hydrogen consumption of the FCHEV powertrains. These control strategies are control strategy based on Efficiency Map (CSEM) and control strategy based on Particle Swarm Optimization (CSPSO). Furthermore, a comparative study of different FCHEV powertrains is provided for adequately selecting of the proper FCHEV powertrain, which could be used in industrial applications. Full article

The aim of this paper is to assess the safety performance of a lightweight hydrogen fuel cell city concept vehicle entitled Microcab [1]. The Microcab is a lightweight 4 seat hydrogen fuel cell concept vehicle with a combined mass (excluding passengers) of less than 800kg. The Microcab has a range of 180 miles; it includes a hydrogen fuel tank pressurised to 350 bar. The research focuses on urban accident scenarios; including frontal, lateral and compatibility loadcases. All loadcases utilise urban speeds, i.e. speeds ranging up to 40km/h for frontal impacts. The crashworthiness of the Microcab has been analysed using explicit non-linear Finite Element Analysis (FEA). The study concludes that within the limitations of the material parameter definitions and mass distributions; the crashworthiness in connection with urban accident scenarios is good. This includes aspects such as vehicle compatibility loadcases and protection of the hydrogen fuel tank e.g. for intrusion. The outcome of the study also suggests structural refinements for the future Microcab final production model; with an aim of further improving the vehicles’ crashworthiness. These refinements include raising the primary front crash structure to better align it with that of a Sports Utility Vehicle (SUV) as well as bracing the fuel cell area in case of a rear impact in order to better protect this vital component. It is also suggested that adhesive joints were suitable for structural crash integrity in all the loadcases studied within this paper, including low speed impact for repairability. A structural optimisation study has also been undertaken utilising Design Of Experiments (DOE), shape- size- and topology optimisation. DOE was employed to further improve the stiffness of the chassis with respect to safety, whilst minimising the mass increase. Topology optimisation models based on the maximum crash force magnitudes computed in the initial part of the study were also setup; the results of these suggested future changes to the Microcabs’ floor layout could be utilised to further enhance the vehicles crashworthiness. Full article

Hydrogen-powered vehicles have long shown great potential to displace fuel. However, due to the lack of infrastructure and the high cost of the components, the technology has not yet been introduced in the market. On the other hand, current battery electric vehicles (BEVs) also hold great promise, but their market penetration is limited due to their range. This study seeks to address the limitations of both technologies with regard to the medium-duty vehicle market by assessing the fuel displacement and cost–benefit potential of adding fuel cell systems to double the current range of BEVs. The addition of a fuel cell system will address drivers’ anxiety over the range of BEVs while minimizing the powertrain cost through optimized component sizing. Full article

EcoCAR 2 is a collegiate level Advanced Vehicle Technology Competition which challenges students to re-engineer a General Motors (GM) donated 2013 Malibu Eco as a plug-in hybrid electric vehicle over the course of three years. The competition is organized by Argonne National Laboratory with the U.S. Department of Energy and GM as the headline sponsors. As part of this competition, Mississippi State University (MSU) has designed a pre-transmission parallel PHEV which utilizes a 145 kW permanent magnet brushless DC motor, a 18.9 kWh Li-ion battery, and a GM 1.4 L turbocharged engine which has been tuned for E85 fuel. A supervisory control system has been utilized to interface the hybrid components to the production vehicle, and implements a control strategy enabling charge depleting (CD) and charge sustaining (CS) modes of operation. In order to develop this control strategy and evaluate the vehicle, a simulation model has been constructed in Matlab Simulink for software-in-the-loop (SIL) and hardware-in-the-loop (HIL) simulation. This vehicle model has been constructed using a combination of dSPACE Automotive Simulation Models and MSU developed component models. Each of these component models has been parameterized from manufacturer provided data in order to ensure the accuracy of the vehicle evaluations. An analysis of the vehicle’s fuel economy has been performed using SIL and HIL simulation over four drive cycles for CD and CS modes of operation. A combined fuel economy has been calculated according to SAE Standard J1711 for both E85 and gasoline fuels. Full article

In this study, component design of x-EVs was performed using virtual integrated development environment (VIDE). First, component library was developed for various components such as the engine, motor, battery and transmission. Vehicle performance simulator of x-EVs was developed using MATALB SimDriveline, which consists of the powertrain system and control system. Experiment and commercial software were used for the validation. A virtual environment was developed using the 3D rendering tool to simulate the road, buildings, traffic, signal system and weather. Using the VIDE, EV range and acceleration performance for various x-EVs were evaluated to design the battery and motor specifications. In addition, an electric heater was selected as an example and its performance at the vehicle level was investigated using the VIDE. It is expected that the VIDE can be used in component design for x-EVs. Full article

For the Dutch Ministry for Infrastructure and the Environment data of plug-in vehicles was collected. Data concerning fueling and charging of plug-in vehicles is collected from lease companies, a fuel-pass company, and the charging infrastruture organisation. More than 10% of the total Dutch plug-in fleet is covered. The electricity data is insufficient to derive a real-world electricity use, e.g., kWh/100km. However, the amount of electric kilometers are determined and verified to be about 24%. A substantial group of users charge the vehicle once or twice a day. However, among the business users, there seems to be a substantial group who do not use the charging capabilities of the plug-in vehicles. The Dutch report is sent by the minister to the Dutch Parliament in June 2013. [3] Full article

The free piston linear generator is a new range-extender technology. It converts chemical energy into electrical energy by means of a combustion process and linear generator. Thereby the technology aims to have better properties than other range extenders. Therefore this publication deals with the explanation of the concept and the characteristics of a free piston linear generator and a comparison to other technologies. In order to compare the range extender systems, fuel cells, micro gas turbine and otto/wankel combustion, will briefly be presented, before being compared to the free piston linear generator. Full article

In recent years, the usage of various alternative energies is considered from a viewpoint of CO2 emission reduction. Toyota Motor Corporation considers that Plug-in Hybrid Electric Vehicles (PHEVs) is the best practical solution, and has launched Prius Plug-in Hybrid in January 2012. Prior to this, in December 2009, Toyota sold 650 PHEVs through lease programs for validation testing in Europe, the U.S. and Japan. As a result, not only the fuel reduction effect in case of real market usage was confirmed, but also the relationship between frequency of charging and fuel reduction effect. This paper discusses the analysis of the validation test results. Full article

New emission standards implemented in EU has resulted in an increasing use of passenger hybrid vehicles as well as hybrid heavy-duty transport vehicles. Manufacturers have been offering a wide range of efficient and lower emission vehicles to fulfil these Regulations. Besides commercial vehicles, it it’s also important to consider the use and implementation of hybrid urban buses because it is a massive way of transportation that is used every day in the bigger cities. The use of hybrid urban buses is significant to achieve the goal for lower emissions and better energy efficiency, due to the city utilization involves several stops and accelerations. This paper considers the comparison between the results obtained from software simulation of a complete in-series hybrid urban bus platform (develop under AVL Cruise® software) and the data obtained from real on-board measurements made in the city of Madrid. The model involves an in-series hybrid electric bus, meaning that the propulsion system is supplied by an electric motor which receives energy from a stored source (battery). The analysis of the results shows a very accuracy approach and lower emission vehicle, with an error below 5% in fuel consumption modelling a real driving cycle up to 8km. Full article

The purpose of the study is to analyze the configurations of Plug-in Hybrid Electric Vehicles (PHEV) with respect to fuel economy. Existing studies mostly focus on hybrid systems or few PHEV systems by only considering power split ratio and component efficiency. This paper adds original contribution to these literatures. First of all, this study compares and analyzes “series + α” PHEV – Input split, Series-output split and Series-parallel, which is consisted of a single Planetary gear or spur gear and clutches. Those are currently applied to mass-production vehicles such as Toyota Prius PHEV, Chevrolet Volt and Honda Accord PHEV. On top of that, it examines the impact of the transmission mechanical losses on Dynamic programming (DP) results and especially the planetary gear loss is modelled using power split ratio analysis. Lastly, the effect of Series mode for each PHEV system is examined by analysis of the theoretical system efficiency and DP in a certain driving profile. From this study the strength and weakness of PHEV systems are revealed depending on a driving condition and battery status, e.g. charging depleting (CD) or charging sustaining (CS). The PHEV system analysis in this study can help select proper system for a certain purpose. Full article

This paper presents an energy and environmental characterization of the two most relevant Plug-in Hybrid Electric Vehicles available in the market (Opel Ampera and Toyota Prius Plug-in), in order to provide an estimate of fuel and electricity consumption, tailpipe emissions and charge depleting mode mileage for any drive cycle studied, based on vehicle specific power methodology. These vehicles were monitored under real-world operation with a portable laboratory that collects data from vehicle sensors (via on-board diagnosis port), exhaust gas composition and GPS in a second-by-second basis. An indirect method to measure battery energy fluxes and consequently estimating electric range was developed, providing maximum errors for the Charge Depleting driving range of 4.2% for the Toyota Prius Plug-in and -0.2% for the Opel, when comparing with measured data. Regarding fuel consumption, the maximum error verified was of -4.1%. Using two driving profiles measured in Portugal and the USA, the performance of the two vehicles under charge depleting (CD) and charge sustaining (CS) conditions was compared. Major findings indicate that Opel Ampera is more efficient in CD mode, while the Prius Plug-In is more efficient under CS conditions, but highly dependent on driving behavior when in CD mode. Full article

The ability to regenerate energy when braking is a valuable advantage of hybrid and fully electric vehicles. How much energy that can be regenerated depends mainly on the car driving and the capacity of the driveline. Detailed studies of possibilities for brake energy regeneration in real world driving are needed to better understand the potential gains of car-electrification since test cycles do not take individual driving or elevation into account. This study has analysed the potential for regeneration in Swedish car driving by applying a model for a normalized vehicle to a highly detailed and representative data set of individual car movements for privately driven cars in Sweden. The share of energy at the wheels used for braking was found to range from 12% to 63%, with an average of 30%. Engine braking could however reduce the amount of recoverable energy to about 16%. On average 42% and 89% of the potentially regenerable energy is available below 10 and 40 kW, respectively. Drivers with lower average speed have in general a higher share of the energy at the wheels potentially available for regeneration. This is however not an important factor to determine the total yearly energy/cost savings. Instead the yearly mileage is shown to be a more relevant indicator on total energy savings from regeneration. The results are compared to the NEDC and WLTP test cycles. Full article

This paper introduces the development and calibration process of a vehicle drivetrain observer used in hybrid and electric vehicles for active damping control (ADC) and for the improvement of the electric machine’s rotor angle signal quality. This approach starts with creating an overall vehicle model that includes the electric machine, the transmission, side shafts, the tires and the vehicle body. For control engineering purposes, that multi-order-model is then reduced into a two-mass-oscillator which can be easily described in state-space form. Using this reduced drivetrain model and applying a Luenberger observer approach, not only the signal quality of both the instrumented rotor angle and the speed of the electric machine can be improved considerably but also the oscillation dynamics of this vehicle drivetrain can be estimated. If not compensated during vehicle operation, drivetrain oscillations might lead to increased drivetrain wear, NVH issues and limited ride comfort; therefore, the oscillation speed is very important in computing an active damping torque that is to compensate drivetrain oscillations. Calibration of the vehicle drivetrain observer is done using specific vehicle test data that are fed into a standalone calibration tool identifying the parameters of the vehicle drivetrain as well as the Luenberger feedback vector. Based on these data, a proper active damping control application is set-up and verified in various vehicle tests and to lead to the calibration finally to the application in several hybrid and electric vehicle series projects (e.g. Peugeot 3008 HYbrid4). Full article

Clutch-brake system is important element in advanced Compact Hybrid Planetary Transmission Drive (CHPTD). The proper designed clutch/brake system equipped with planetary transmission and additional gears could save energy and improve performance of hybrid powertrain, especially during frequent vehicle starting and regenerative braking. This paper dedicate to design of clutch engaging control strategy in ICE starting procedure. The control of each element in CHPTD during ICE starting is described. Different clutch engaging control strategies are proposed and validated on laboratory stand for various conditions. Optimized control strategy for clutch engaging is selected by analysing the simulation and experimental test results. Full article

Power split driveline ensures a hybrid vehicle good performance in fuel economy and emissions, but might bring about serious torsional vibrations at city traffic operation. A power split driveline is addressed in this paper to understand the mechanism behind the failure of its transmission shaft. Lumped-parameter models were established for the system at various engine and motor configurations corresponding to typical working conditions. Natural frequencies and mode shapes were calculated for each configuration. Sensitivity analysis reveals the variation of the natural frequencies with respect to the inertia or stiffness of the system. It is revealed that there exists unavoidable resonance with the system during vehicle operation, which should be the main reason of the shaft failure. Full article

The Netherlands Organisation for Applied Scientific Research (TNO) is engaged in research, development and testing of a range of technologies relating to hybrid and electric vehicle energy management and performance. The impact of driver behaviour on vehicle energy consumption is a significant factor, and one which can often be reduced with eco-driving, typically 5-10% or higher in some cases. Eco-driving can be extended not only to take into account information sources, improved user acceptance, and integration with powertrain control. In this paper, TNO illustrates the possible applications of model-based control for (hybrid) electric vehicles and shows preliminary results of the developed system. Full article

A new two-motor hybrid system is developed to maximize powertrain efficiency. Efficiency of the system is drastically enhanced without any driving performance sacrifices by switching driving modes from "Hybrid Drive" to "EV (Electric vehicle) Drive" or "Engine Drive" according to the driving condition, along with the application of a series hybrid based system to make full use of high flexibility of engine operating points. Basic concepts of the maximization of powertrain efficiency including an applied system configuration and control technologies are discussed in this paper. Along with this system, a high capacity Li-ion battery and an on-board charger are installed in 2014 Honda Accord Plug-In to add practical plug-in HEV capabilities. Superior fuel economy is achieved with values of 46 MPG (Miles Per Gallon) in CS (Charge Sustaining) mode, 115 MPGe (Miles Per Gallon equivalent) in CD (Charge Depleting) mode and 13miles of AER (All Electric Range). MPGe is a unit of fuel economy for the alternate fuel vehicles such as plug-in hybrid electric vehicles or electric vehicles. The ratings are calculated by converting used electric energy into equivalent amount of gasoline. Full article

Increasing demands of eco-friendly vehicles, various types of hybrid electric vehicle (HEV) have been researched and released. Recently, some research has interest in not only the efficiency of the vehicle but also the durability of battery because the life of battery has influence on the cost of maintenance, stability and performance of the vehicle. In this study, backward simulation based on dynamic programming depending on the type of HEV which is consists of engine and battery or engine, battery and ultra-capacitor was conducted. The developed backward simulation algorithm can calculate the optimal fuel economy according to the driving cycle and other vehicle and components conditions. For the analysis of battery life, a battery capacity fade model was applied to the result of backward simulation. Battery life was estimated with an assumption that the vehicle drives repeatedly to follow the result of backward simulation derived to find the optimal fuel economy. From the simulation results, it is shown that HEV with ultra-capacitor has better fuel economy though it is almost similar with HEV without ultra-capacitor. However, the battery life of HEV with ultra-capacitor was estimated better because of the difference of battery power usage. Consequently, applying the ultra-capacitor to the typical parallel HEV has no large advantage in terms of fuel economy but has significant benefit in terms of battery life. Full article

In this work a novel series hybrid powertrain concept is presented. The concept removes the requirement for a power electronic converter to manage the state of charge of the accumulators by controlling the power flow between the generator and accumulator. Instead, the engine and generator are directly coupled and the state of charge of the accumulators is maintained by controlling the speed and power output of the engine to control the power flow to the accumulators. Results are presented from a proof-of-concept system that was built for a vehicle with a target peak power of 60kW with supercapacitors. Models are also presented comparing and contrasting a battery version with the supercapacitor version for a Formula Student vehicle. The powertrain is particularly suited for applications which have very high torque requirements, and hence the use of a mechanical gearbox introduces significant cost & weight, and is also ideally suited for applications where power needs to be distributed throughout an application to multiple locations, and hence multiple mechanical linkages would normally be required. The supercapacitor version is most suited to applications with high peak to average load ratios and noisy load cycles, and the battery version could be seen as a low cost route to range extend a battery electric vehicle. Full article

The parallel hybrid configuration in which a clutch is installed between an engine and a motor can shift its operation mode between pure electric and hybrid vehicle mode by engaging or disengaging the clutch. To enhance drivability of the system in shifting its operation mode, it is required to prepare appropriate measures to control the clutch in response to driving conditions. This paper introduces the hydraulic clutch control strategy which is composed of a synchronized engaging and a launch slip engaging maneuver. The strategy also covers the criteria to decide the proper engaging method between above two candidates for current circumstance. This study also deals with the learning algorithm to compensate the variations of the clutch hardware and to realize consistent drivability across all units. The learning algorithm utilizes the traction motor and a pressure sensor to identify the all the variation terms of the clutch with the required level of accuracy Full article

This paper presents the design and validation of a novel multi-mode transmission (MMT) for a hybrid electric vehicle (HEV) using a single electric machine (EM), which implies compact and low cost. The topology of the MMT planetary gearset is the same as that of conventional four speed automatic transmissions. The MMT uses two planetary gearsets and four clutches to combine an engine and an EM with the vehicle, and the EM is operated as a motor or a generator. The MMT realizes five power flow modes, which are developed into sixteen operating modes, including one motor-only mode, four engine-only modes, four compound driving modes, six braking modes, and one charging while parking mode. The single EM HEV solution avoids losses from another EM and extra power electronics which are employed in many existing HEVs. The properly arranged clutches transmit power flow more flexibly, allow direct mechanical power transmission from the engine to the drive shaft, and avoid spin loss for the engine and energy conversion loss for the electric components. The fuel consumption of the proposed hybrid vehicle system is compared with a benchmark vehicle which uses a planetary gearset, two EMs and no clutch. Simulation results under New European Driving Cycle show that the fuel consumption of the proposed HEV is comparable to the benchmark vehicle. Reasons for comparable results are explored, which indicates the fuel economy potential of the new concept. Full article

This paper represents the latest results of the FP7 European Project SuperLIB: Advanced Dual-Cell Battery Concept for Battery Electric Vehicles. The electrical characteristics of the proposed hybrid topology based on high power and high-energy cells are presented. In the framework of project, dedicated research work has been carried out in the field of characterization and modeling. From these characterization results advanced simulation models have been developed for investigation and prediction of the proposed hybrid concept in detail based on innovative simulation tool for evaluation and optimization of the power flow in the driveline. From the simulation results have been concluded that the performances of the vehicle can be enhanced in terms of power capabilities and range extension. Then, the results also show that the abilities of the highenergy battery can be improved in terms of energy efficiency, voltage drop and heat development inside the battery. Finally the comparative analysis illustrates that the SuperLIB hybrid architecture has several merits against the hybrid topology based on high-energy batteries and electrical double-layer capacitors in terms of weight and volume. Full article

In this paper, a motor-generator (MG) control algorithm was proposed to improve the shift quality for a dual mode power split transmission (PST) hybrid electric vehicle (HEV). In order to analyze the shift characteristics during the mode shift, Bondgraph models for transient-state were constructed and state equations were derived. From the state equations, it was found that inertia torque of MG2 causes a transient torque during the mode shift. Based on the transient torque, a MG torque control algorithm which compensates the transient torque was developed to reduce the driveshaft torque variation. To evaluate the performance of the MG2 control algorithm, dynamic models of the dual mode PST HEV were obtained and an AMESim-MATLAB/Simulink based mode shift performance simulator was developed. It was found from the simulation results that the driveshaft torque variation was reduced by the proposed control algorithm which provides improved shift quality Full article

As a selected participant in the EcoCAR2: Plugging In to the Future competition, headline sponsored by General Motors and the US Department of Energy, the Rose-Hulman team has completed the second year of a three year design cycle. This paper focuses on the supervisory control system design completed during year one of the competition including plant model development, control system hardware architecture, control system software architecture, vehicle operational modes, automated testing, and fault detection and mitigation. Full article

This research proposes a regenerative braking co-operative control system for the automatic transmission (AT)-based hybrid electric vehicle (HEV). The brake system of the subject HEV consists of the regenerative braking and the electronic wedge brake (EWB) friction braking for the front wheel, and the hydraulic friction braking for the rear wheel. A regenerative braking co-operative control algorithm is suggested for the regenerative braking and friction braking, which distributes the braking torque according to the driver’s demand. A vehicle test was performed to evaluate the proposed braking system and cooperative control algorithm. Full article

A Continuous Variable Transmission (CVT) is introduced in the simulation model of a Hybrid Electric Vehicle (HEV). The CVT-based vehicle simulation and its control are deduced from the Energetic Macroscopic Representation (EMR). Simulations are provided to show the interest of the CVT in term of fuel consumption Full article