578 research outputs found
Next Generation HEV Powertrain Design Tools: Roadmap and Challenges
Hybrid electric vehicles (HEVs) represent a fundamental step in the global evolution towards transportation electrification. Nevertheless, they exhibit a remarkably complex design environment with respect to both traditional internal combustion engine vehicles and battery electric vehicles. Innovative and advanced design tools are therefore crucially required to effectively handle the increased complexity of HEV development processes. This paper aims at providing a comprehensive overview of past and current advancements in HEV powertrain design methodologies. Subsequently, major simplifications and limits of current HEV design methodologies are detailed. The final part of this paper defines research challenges that need accomplishment to develop the next generation HEV architecture design tools. These particularly include the application of multi-fidelity modeling approaches, the embedded design of powertrain architecture and on-board control logic and the endorsement of multi-disciplinary optimization procedures. Resolving these issues may indeed remarkably foster the widespread adoption of HEVs in the global vehicle market
Hybrid and Electric Vehicles Optimal Design and Real-time Control based on Artificial Intelligence
L'abstract è presente nell'allegato / the abstract is in the attachmen
Overview of Sensitivity Analysis Methods Capabilities for Traction AC Machines in Electrified Vehicles
© 2021 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/.A robust design in electrified powertrains substantially helps to enhance the vehicle's overall efficiency. Robustness analyses come with complexity and computational costs at the vehicle level. The use of sensitivity analysis (SA) methods in the design phase has gained popularity in recent years to improve the performance of road vehicles while optimizing the resources, reducing the costs, and shortening the development time. Designers have started to utilize the SA methods to explore: i) how the component and vehicle level design options affect the main outputs i.e. energy efficiency and energy consumption; ii) observing sub-dependent parameters, which might be influenced by the variation of the targeted controllable (i.e. magnet thickness) and uncontrollable (i.e. magnet temperature) variables, in nonlinear dynamic systems; and iii) evaluating the interactions, of both dependent, and sub-dependent controllable/uncontrollable variables, under transient conditions. Hence the aim of this study is to succinctly review recent utilization of SA methods in the design of AC electric machines (EM)s used in vehicle powertrains, to evaluate and discuss the findings presented in recent research papers while summarizing the current state of knowledge. By systematically reviewing the literature on applied SAs in electrified powertrains, we offer a bibliometric analysis of the trends of application-oriented SA studies in the last and next decades. Finally, a numerical-based case study on a third-generation TOYOTA Prius EM will be given, to verify the SA-related findings of this article, alongside future works recommendations.Peer reviewe
Hydraulic Brake Systems for Electrified Road Vehicles: A Down-sizing Approach
Down-sizing hydraulic brake systems can is made possible in electrified road vehicles thanks to the braking torque contribution provided by electric machines. Benefits in terms of weight and cost of the system can be ensured in this way. Nevertheless, appropriate care should be taken not to excessively deteriorate the overall electrical energy recovery capability of the electrified vehicle during braking maneuvers. For this reason, a multi-target optimization framework is developed in this paper to down-size hydraulic brake systems for electrified road vehicles while simultaneously maximizing the braking energy recovery capability of the electrified powertrain. Firstly, hydraulic brake system, electrified powertrain and vehicle chassis are modeled in a dedicated simulation platform. Subsequently, particle-swarm optimization is employed as search algorithm to identify optimal sizing parameters for the hydraulic brake system. Sizing variables particularly include diameter and stroke of the master cylinder, electrically assisted booster diameter, front brake piston diameter and rear brake piston diameter. The simulation of homologation tests for safety standards ensures that retained combinations of sizing parameters complies with regulatory requirements. A case study proves that the developed methodology is flexible and effective at rapidly producing several sub-optimal sizing options for both front-wheel drive and rear-wheel drive layouts for a retained battery electric vehicle
Electromobility Studies Based on Convex Optimization DESIGN AND CONTROL ISSUES REGARDING VEHICLE ELECTRIFICATION
This article presents a framework to study design tradeoffs
in the search for electromobility solutions based on approximate
modeling of the power flows in the powertrain as a
function of component sizes. An important consequence of
the modeling assumptions is that the optimal energy management
and component sizes can be computed simultaneously
in a convex program, which means that competing
designs can be evaluated in an objective way, avoiding the
influence of a separate control system design. The fact that
the optimization problem is convex allows large problems
to be solved with moderate computational resources, which
can be exploited by, for example, running optimizations
over very long driving cycles. The problem formulation
also admits design decisions for the charging infrastructure
to be included in the optimization
MODEL-BASED CONTROL OF HYBRID ELECTRIC POWERTRAINS INTEGRATED WITH LOW TEMPERATURE COMBUSTION ENGINES
Powertrain electrification including hybridizing advanced combustion engines is a viable cost-effective solution to improve fuel economy of vehicles. This will provide opportunity for narrow-range high-efficiency combustion regimes to be able to operate and consequently improve vehicle’s fuel conversion efficiency, compared to conventional hybrid electric vehicles (HEV)s. Low temperature combustion (LTC) engines offer the highest peak brake thermal efficiency reported in literature, but these engines have narrow operating range. In addition, LTC engines have ultra-low soot and nitrogen oxides (NOx) emissions, compared to conventional compression ignition and spark ignition (SI) engines. This dissertation concentrates on integrating the LTC engines (i) in series HEV and extended range electric vehicle (E-REV) architectures which decouple the engine from the drivetrain and allow the ICE to operate fully in a dedicated LTC mode, and (ii) a parallel HEV architecture to investigate optimum performance for fuel saving by utilizing electric torque assist level offered by e-motor. An electrified LTC-SI powertrain test setup is built at Michigan Technological University to develop the powertrain efficiency maps to be used in energy management control (EMC) framework.
Three different types of Energy Management Control (EMC) strategies are developed. The EMC strategies encompass thermostatic rule-based control (RBC), offline (i.e., dynamic programing (DP) and pontryagin’s minimum principal (PMP)), and online optimization (i.e., model predictive control (MPC)). The developed EMC strategies are then implemented on experimentally validated HEV powertrain model to investigate the powertrain fuel economy. A dedicated single-mode homogeneous charge compression ignition (HCCI) and reactivity controlled compression ignition (RCCI) engines are integrated with series HEV powertrain. The results show up to 17.7% and 14.2% fuel economy saving of using HCCI and RCCI, respectively in series HEV compared to modern SI engine in the similar architecture. In addition, the MPC results show that sub-optimal fuel economy is achieved by predicting the vehicle speed profile for a time horizon of 70 sec.
Furthermore, a multi-mode LTC-SI engine is integrated in both series and parallel HEVs. The developed multi-mode LTC-SI engine enables flexibility in combustion mode-switching over the driving cycle, which helps to improve the overall fuel economy. The engine operation modes include HCCI, RCCI, and SI modes. The powertrain controller is designed to enable switching among different modes, with minimum fuel penalty for transient engine operations. In the parallel HEV architecture, the results for the UDDS driving cycle show the maximum benefit of the multi-mode LTCSI engine is realized in the mild electrification level, where the LTC mode operating time increases dramatically from 5.0% in Plug-in Hybrid Electric Vehicle (PHEV) to 20.5% in mild HEV
CO2 reduction through low cost electrification of the diesel powertrain at 48V
In order to achieve fleet average CO2 targets, mass market adoption of low CO2 technologies is required. Application of low cost technologies across a large number of vehicles is more cost-effective in reducing fleet CO2 than deploying high-impact, costly technology to a few. Therefore, to meet the CO2 reduction challenge, commercially viable, low cost technologies are of significant interest. This paper presents results from the ‘ADEPT’ collaborative research program which focuses on CO2 reduction through the application of intelligent 48V electrification to diesel engines for passenger car applications. Results were demonstrated on a C-segment vehicle with a class-leading 4-cylinder 1.5 litre Euro 6 diesel engine. Electrification was applied through a high power, high efficiency, switched reluctance belt integrated starter generator (B-ISG) capable of both generation and motoring, and an Advanced Lead Carbon Battery for energy storage. The conventional alternator was replaced with a highly efficient DC-DC converter to supply energy to the 12V system. These technologies enabled powertrain efficiency improvement through the recovery of kinetic energy with regenerative braking and reapplication of the recovered energy through motoring to offset fuel usage. Efficiency was further optimised through application of engine downspeeding and advanced auto-stop strategies to extended engine-off time. Additional electrification was investigated through 48V ancillaries, including water-pump and air-conditioning compressor, and a turbo-compound generator for waste heat recovery from exhaust gas. These technologies have demonstrated a combined CO2 reduction of 10–11% against the conventional vehicle baseline. Additional studies of advanced thermal systems for improved warm-up, and lubrication control for FMEP reduction have also been conducted on this program. These indicate that by applying intelligent electrification to ancillaries a further 3–4% reduction in CO2 is achievable. Overall, this program shows that 48V technologies can achieve CO2 savings with a lower cost per gram CO2 than full hybrid solutions
- …