Simulation-Based Power Strategy Optimization in a Diesel Hybrid Vehicle

Hybridization of hydraulic drivetrains offers the potential of efficiency improvement for on- and off-road applications. To realize the advantages, a carefully designed system and corresponding control strategy are required, which are commonly obtained through a sequential design process.Addressing component selection and control parameterization simultaneously through simulation-based optimization allows for exploration of a large design space as well as design relations and trade-offs, and their evaluation in dynamic conditions which exist in real driving scenarios. In this paper, the optimization framework for a hydraulic hybrid vehicle is introduced, including the simulation model for a series hybrid architecture and component scaling considerations impacting the system’s performance.Anumber of optimization experiments for an on-road light-duty vehicle, focused on standard-drivecycle- performance, illustrate the impact of the problem formulation on the final design and thus the complexity of the design problem. The designs found demonstrate both the potential of energy storage in series hybrids, via an energy balance diagram, as well as some challenges. The framework presented here provides a base for systematic evaluation of design alternatives and problem formulation aspects.

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Hybridization of a vehicle’s drivetrain can in principle help to improve its energy efficiency by allowing for recuperation of kinetic energy and modulating the engine’s load. How well this can be realized depends on appropriate sizing and control of the additional components. The system is typically designed sequentially, with the hardware setup preceding the development and tuning of advanced controller architectures. Taking an alternative approach, component sizing and controller tuning can be addressed simultaneously through simulation-based optimization. The results of such optimizations, especially with standard algorithms with continuous design variable ranges, can however be difficult to realize, considering for example limitations in available components. Furthermore, drive-cycle based optimizations are prone to cycle-beating. This paper examines the results of such simulation-based optimization for a series hydraulic hybrid vehicle in terms of sensitivity to variations in design parameters, system parameters and drive cycle variations. Additional relevant aspects concerning the definition of the optimization problem are pointed out.

Hybridisation of hydraulic drivetrains offers the potential of efficiency improvement for on – and off-road applications. To realise the advantages, a carefully designed system and corresponding co ...

The object of this study is the field of patenting of technological advances registered in the world in the field of automotive power plants. The subject of the study is the dynamics of patenting in the automotive power plant industry, associated with the need to harmonize the trajectories of technological development with global trends in energy efficiency and manufacturability, in order to ensure sustainable economic growth. Patenting in the industry is considered in the following areas: gasoline engines, diesel engines, hybrid cars, electric cars, hydrogen cars. The relevance of this study is determined by the general desire of society to innovate through the latest tools and the introduction of systemic measures to comprehensively address the problem of increasing energy efficiency and reducing air pollution caused by road transport. The paper analyzes the statistics of patents registered in the world, examines patent activity and trends in the patenting of technological advances in the automotive industry from 2010 to 2022. In the industry of gasoline and diesel engines, hybrid vehicles, electric vehicles and hydrogen vehicles, the current work investigates through systematization and analysis of important aspects of patenting statistics and innovation dynamics. For the period of 2017–2022, the average increase in the number of registered patents per year compared to the previous period was found to be 1.37 times higher for the area of "hybrid vehicles", 1.3 times higher for the area of "electric vehicles", and 26 times higher for the area of "hydrogen vehicles". A comparative analysis of the number of registered patents by areas was carried out, further patenting rates were predicted, and priority areas of research and innovation were identified

This paper describes the development of a Volterra series model for predicting transient soot emissions from a diesel engine with fuel flow rate and engine speed as the two inputs to the model. These two signals are usually available as outputs of the power management controller in diesel hybrids. Therefore, an accurate offline estimation of the transient soot emissions using these signals is instrumental in optimizing the control strategy for both fuel economy and emissions. In order to develop the model, transient soot data are first collected by Engine-in-the-loop experiments of conventional and hybrid vehicles. The data are then used to construct a third-order multiple-input single-output (MISO) Volterra series to successfully model this system. Parametric complexity of the model is reduced using proper orthogonal decomposition (POD), and the model is validated on various datasets. It is shown that the prediction accuracy of transient soot, both qualitatively and quantitatively, significantly improves over the steady-state maps, while the model still remains computationally efficient for systems level work.

This paper presents results from gasoline- and diesel-powered hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) that account for the interaction of drive cycle transients and engine start–stop events with after-treatment devices and their associated fuel penalties. These simulations were conducted using the Powertrain Systems Analysis Toolkit software combined with after-treatment component models developed at Oak Ridge National Laboratory. The present authors employed a three-way catalyst model for gasoline emissions control and a lean nitrogen oxide (NO x) trap model to simulate diesel exhaust NO x reduction. A previously reported methodology based on experimentally calibrated corrections to steady state maps was used to simulate engine-out emissions and thermal variations. As expected, the simulations indicate a higher baseline fuel efficiency for diesel-powered hybrid vehicles, but this advantage is reduced by about a third for both HEVs and PHEVs when the fuel penalty for the lean NO x trap is included. These preliminary studies demonstrate that existing engine and exhaust systems models can capture important features of the highly transient engine operation in hybrid vehicles and can provide useful comparisons between advanced hybrid vehicle engine options.

Models of integrated vehicle systems are essential for designing hybrid vehicles by means of simulation-based optimization. Given the complexity of hybrid vehicle systems, designing is a time consuming process that requires the evaluation of a large number of different design configurations. Modelling and simulation can significantly reduce the design time through efficient design evaluations and reduced number of prototypes built. This work presents the development and reduction of an integrated hybrid vehicle model composed of an engine, drivetrain, hydraulics and vehicle dynamics subsystems. For model development the bond graph formulation is used because it facilitates the integration of component/subsystem models in different energy domains, supports hierarchical modelling and allows straightforward manipulation of the model. The model is configured for a medium size military truck, and implemented in the 20SIM modelling and simulation environment. After developing the model, an energy-based model reduction methodology is applied in order to generate a reduced vehicle model that provides more design insight. The generated reduced system model for the hybrid truck (compared to the full model) produces almost identical predictions, has almost half the size and calculates the system response 2.5 times faster. This computationally efficient reduced model can be used for vehicle design studies to further reduce the development time.

This research presents a bus fleet replacement optimization model to analyze vehicle replacement decisions when there are competing technologies. The focus of the paper is on sensitivity analysis. Model properties that are useful for sensitivity analysis are derived and applied utilizing real-world data from King County (Seattle) transit agency. Two distinct technologies, diesel hybrid and conventional diesel vehicles, are studied. Key variables affecting optimal bus type and replacement age are analyzed. Breakeven values and elasticity values are estimated. Results indicate that a government purchase cost subsidy has the highest impact on optimal replacement periods and total net cost. Maintenance costs affect the optimal replacement age but are unlikely to change the optimal vehicle type. Greenhouse gas emissions costs are not significant and affect neither bus type nor replacement age.

BackgroundAir pollution is a major health concern in worldwide. Non-methane volatile organic compounds (NMVOCs) are precursors of secondary air pollutants, with road transport being responsible of ~ 90% for the EU-27’s NMVOCs transport emissions in 2021. A series of VOC emissions from 17 modern gasoline, Diesel and Plug-in hybrid (PHEV) vehicles were investigated under various driving conditions and temperatures. All tested vehicles meet the latest European emission standard (Euro 6d and Euro 6d-TEMP). The different VOC species were measured with a Fourier-Transform Infrared Analyzer (FTIR).ResultsDiesel vehicles presented the lowest VOC emissions, while PHEVs operating in charge sustaining mode, with a depleted battery, exhibited very similar behavior to conventional gasoline. Among the VOCs, C5 compounds were the primary contributors to total NMVOCs over WLTC at 23 °C for gasoline and PHEV vehicles. A proportional increase in VOC emissions at colder temperatures, affecting all the studied species, was observed. Significant increases were observed for Aromatics, with an important contribution of < C5 as well. On the other hand, VOC emissions from Diesel vehicles were consistently low and little affected by temperature, except for Aldehydes in tests at − 7 °C. VOC emissions primarily occurred during cold starts, with urban cycle showing higher emission factors due to its shorter distance. VOC emissions remained consistently low during the highway cycle, highlighting a significant reduction in VOC emissions once the after-treatment system (ATS) was warmed up, even under demanding conditions. In Diesel vehicles, total VOCs measured with the FTIR exhibited a slight tendency to exceed Total Hydrocarbons (THC) measured with a Flame Ionization Detector (FID), while for gasoline vehicles and PHEVs, the trend was temperature-dependent.ConclusionsIn summary, the study shows that VOC emissions from Diesel vehicles are significantly lower compared to modern gasoline and PHEV vehicles. Moreover, gasoline and PHEV vehicles exhibit similar levels and emission profiles of VOC emissions. Additionally, ambient temperatures and driving conditions have a significant impact on VOC emissions for all the powertrain technologies investigated.

While improvement works for internal combustion engines intended for decreasing exhaust gases which cause on-road vehicles based climate change are going on, the use of alternative fuel and alternative energy resources is on the increase. But there are certain criteria to negotiate for this kind of vehicles to be approved. These are the constraints such as; high initial investment cost for vehicles, limited fuel storage capacities and limited range. In addition to these, the problems such as safety and liability, high fuel filling costs, limited fuel/charging stations, infrastructure (network improvement) investments, developments in current trends mustn’t be ignored. In addition to conventional petrol and diesel engines, hybrid and full electric vehicle practices are becoming widespread in today’s cars. Another issue is that cars are parked during 90-95% of the day and parking functions require a number of structural changes. In this context, charging units and safe parking conditions are required to be provided in the parking lots in order to perform the charging operations of full electric vehicles (BEV), and especially rechargeable hybrids (PHEV, ReEV, EREV and RXBEV). In this study, the safety and functional integrity of external rechargeable hybrid and electric vehicles and charging units as well as parking lots will be examined.

Electric hybridization is a very effective approach for reducing fuel consumption in light-duty vehicles. Lean combustion engines (including diesels) have also been shown to be significantly more fuel efficient than stoichiometric gasoline engines. Ideally, the combination of these two technologies would result in even more fuel efficient vehicles. However, one major barrier to achieving this goal is the implementation of lean-exhaust aftertreatment that can meet increasingly stringent emissions regulations without heavily penalizing fuel efficiency. We summarize results from comparative simulations of hybrid electric vehicles with either stoichiometric gasoline or diesel engines that include state-of-the-art aftertreatment emissions controls for both stoichiometric and lean exhaust. Fuel consumption and emissions for comparable gasoline and diesel light-duty hybrid electric vehicles were compared over a standard urban drive cycle and potential benefits for utilizing diesel hybrids were identified. Technical barriers and opportunities for improving the efficiency of diesel hybrids were identified.

Having originated in Japan and the US, a worldwide trend can be seen toward hybrid vehicles with gasoline engines. In Europe, by contrast, the diesel engine is increasingly gaining ground as a means of vehicle propulsion. In other markets, such as North America and the emerging markets, the diesel engine is also expected to grow. Both drive concepts are flexible and efficient, enjoy a favorable image among consumers and are attracting ever greater demand on the market despite their more expensive technology. This is because they combine very good performance with low consumption in the light of spiraling fuel prices. This article by IAV deals about the chances of diesel hybrid vehicles.

In contrast to road-based traffic, the track as well as the corresponding duty cycle for railways are known beforehand, which represents a great advantage during the development of operating strategies for hybrid vehicles. Hence the benefits of hybrid vehicles regarding the fuel consumption can be exploited by means of an off-line optimisation. In this article, the fuel-optimal operating strategy is calculated for one specified track using two hybrid railway vehicles with different kinds of energy storage systems: on the one hand, a lithium-ion battery (high-energy storage) and, on the other, a double layer capacitor (high-power storage). For this purpose, control-oriented simulation models are developed for each architecture addressing the main effects contributing to the longitudinal dynamics of the power train. Based on these simulation models, the fuel-optimal operating strategy is calculated by two different approaches: Bellman’s dynamic programming, a wellknown approach in this field, and an innovative sensitivity-based optimisation.

Hybrid electric vehicles are widely seen as potential solutions to the problems of exhaust emissions, fuel consumption and technical challenges to increase vehicle functionality. The present paper focuses on the design, development and performance evaluation of a parallel hybrid electric vehicle based on the concept of a new parallel hybrid transmission. A light pickup diesel vehicle is selected as a platform for hybridization because this category of vehicles consumes a lot of fuel. A prototype of the new transmission system comprised of a coupled planetary gear set, clutches and brakes is built. This transmission utilizes two planetary gear trains coupled for multispeed capability and, has the ability to operate two power sources and to control such power sources independently from one another. To demonstrate the practical applicability of the transmission and this hybrid configuration, one prototype vehicle is built integrating the new transmission system. Since lead acid batteries are available in Indian market, so these batteries are considered in the development. The prototype vehicle is tested on a chassis dynamometer and on test tracks. The acceleration performance of the hybrid vehicle is improved by about 25% over that of the baseline vehicle. An improvement of about 21% in the fuel economy of the hybrid vehicle is measured. The greenhouse gas emissions from the hybrid vehicle are reduced in proportion to fuel consumption. It is a fail-safe design. The new transmission system is proved to be a viable option for parallel hybrid electric vehicles in light duty applications.