Internal Combustion Engine Generator Research Articles

Integrated simulation and performance analysis of Confined Piston Linear Generator (CPLG)

In this study, an energy conversion device referred to Confined Piston Linear Generator (CPLG) is proposed. Moreover, a modeling approach which takes the time-varying and non-linear factors into account is presented to build a real-time integrated model of the CPLG system. The Internal Combustion Engine (ICE) and Permanent Magnet Synchronous Linear Generator (PMSLG) model were built by GT-Power and Maxwell respectively, as well as the date transformation between them was realized by Simulink. The results indicated that, the shutdown areas of the PMSLG are located in the region of low load, low speed or low external load resistance. As the rise of external load resistance, the shutdown area A exists in the conditions of low load, and gradually moves to the high-speed region and reduces or even disappears, while the shutdown area B appears in the low-speed region and expands to the high-speed region. Within the operating area of the PMSLG, the energy conversion efficiency of the CPLG system is improved by 2.32% compared with the prototype ICE. In respect of parameter analysis, the influence of intake pressure on output power is much greater than those of ignition timing, air-fuel ratio and compression ratio.

Design Exploration for Sustainable Regional Hybrid-Electric Aircraft: A Study Based on Technology Forecasts

The environmental impact of aviation in terms of noise and pollutant emissions has gained public attention in the last few years. In addition, the foreseen financial benefits of an increased energy efficiency have motivated the transport industry to invest in propulsion alternatives. This work is collocated within the Clean Sky 2 project GENESIS, focused on the environmental sustainability of 50-passenger hybrid-electric aircraft from a life-cycle-based perspective to support the development of a technology roadmap for transitioning towards sustainable and competitive electric aircraft systems. While several studies have already focused on the definition of possible aircraft designs combining several propulsion systems, the novelty of the present work is to consider technology forecasts and more comprehensive indicators in the design phase. These include the performance and emissions on a 200 nmi typical mission, which reflects the most economically attractive range for aircraft in the regional class. The work proposes a complete exploration of three major technology streams for energy storage: batteries, fuel cells, and turbine internal combustion engine generators, also including possible combinations of those technologies. The exploration was carried out through the execution of several designs of experiments aiming at the identification of the most promising solutions in terms of aircraft configuration for three different time horizons: short-term, 2025–2035; medium-term, 2035–2045; and long-term, 2045–2050+. As a result, in the short-term scenario, fuel energy consumption is estimated to be reduced by around 24% with respect to conventional aircraft with the same entry-into-service year thanks to the use of hybrid propulsive systems with lithium batteries. Fuel saving increases to 45% in the medium-term horizon due to the improvement in the energy density of storage systems. By the year 2050, when hydrogen fuel cells are estimated to be mature enough to completely replace kerosene-based engines, the forthcoming hybrid-electric aircraft promise no NOx and CO2 direct emissions, while being approximately 50% heavier than conventional ones.

Comparing the profitability of waste heat electricity generation of internal combustion engines: An exergoeconomic analysis through optimization of two different organic Rankine cycle scenarios

• Two heat recovery scenarios from ICE with the aim of using in ORC cycle is studied. • The scenarios were designed based on heat recovery from exhaust and jacket water. • A comprehensive program based on energy and exergoeconomic analysis is developed. • The effects of refrigerant type and thermodynamic conditions for each scenario is studied. • The optimum scenario based on higher electricity generation or efficiency is introduced. The increasing consumption of fossil fuels has caused the emission of an enormous amount of greenhouse gases it has led to the problem of global warming and other damages to the environment. Therefore, heat recovery has become very important in recent years. In this paper, two different scenarios of the Organic Rankine cycle (ORC) are proposed to heat recovery of an internal combustion engine with two heat loss levels (stack and jacket water). The novelty of this paper is the comparison of the application of two different scenarios for the use of two available heat sources that have not been studied in previous research. Three different types of organic fluids including dry (n-butane and R245fa), wet (R134a) and isentropic (R123) were studied by energy, exergy and economic analysis. In addition, the parameters of pressure and the inlet temperature of the turbine and the superheat temperature value of the inlet flow to the turbine were optimized by the multi-objective optimization. The optimization results showed that the parameter influencing the thermodynamic and economic indicators most is the ORC pressure ratio. The optimized results of the two scenarios were compared according to thermodynamic and economic analysis and the best results were obtained for scenario 2 and fluid R123. For this case, the levelized cost of electricity (LCOE), Total Investment Cost (TIC) and electricity generation are 0.05776 $/kWh, 317,528 $ and 202.5 kW, respectively. Moreover, studying 20 countries in all the five continents, showed that developed countries were the ones with the minimum and maximum payback periods.

Simulation about the Effect of the Height-to-Stroke Ratios of Ports on Power and Emissions in an OP2S Engine Using Diesel/Methanol Blends

Zero carbon emissions will dominate the future of internal combustion engines (ICEs). Existing technology has pushed the performance of ICEs operating on traditional working principles to almost reach their limit. The new generation of ICEs needs to explore new efficient combustion modes. For new combustion modes to simplify the emission after treatment, the opposed-piston, two-stroke (OP2S) diesel engine is a powertrain with great potential value. Combined with dual-fuel technology, the OP2S diesel engine can effectively reduce carbon emissions to achieve clean combustion. Hence, methanol/diesel dual fuel was burnt in the OP2S engine to create a clean combustion mode for future demands. In the present work, a 1D simulation model of an OP2S diesel engine was established and verified. We investigated the influence of port height to stroke ratio (HSR) on power and emission performances of the OP2S diesel engine under different methanol ratios. The results show that the methanol ratio extremely influences the indicated power (IP) with the HSR of intake ports increasing. The IP decreases by about 1.8–2.0% for every 5% increase in methanol. Correspondingly, the methanol ratio extremely influences the indicated thermal efficiency (ITE), with the HSR of exhaust ports increasing. The ITE increases by about 2.1–3.1% for every 5% increase in methanol. The increasing methanol ratio reduces the HSR of ports for the optimal IP and ITE. To balance power performance and emission performance, the methanol ratio should be kept to 10–15%.

Software strategy for internal combustion engine and electric motor control on a hybrid electric vehicle equipped with belt starter generator and automated manual transmission

In order to fulfil the latest EU emission standards, the average amount of CO2 emissions for each vehicle sold has to be reduced to avoid fines for manufacturers. One of the simplest and cheapest ways of hybridization is the belt starter generator (BSG), which makes it suitable for an entry-level range of vehicles. This paper presents a software strategy developed for internal combustion engine (ICE) and belt starter generator (BSG) control on a vehicle equipped with automated manual transmission and also the drivability, comfort and emission performances improvements expected by using this strategy.

Effects of Backpressure on the Performance of Internal Combustion Engine and Automobile Exhaust Thermoelectric Generator

Abstract The maximum generated power of automobile exhaust thermoelectric generator (AETEG) can be enhanced by applying inserted fins to its heat exchanger, because the temperature difference of thermoelectric modules (TEMs) is increased. However, the added heat exchanger will result in undesired backpressure, which may deteriorate the performance of the internal combustion engine (ICE). To evaluate the backpressure on the performance of both the ICE and the AETEG, the model of ICE integrated with AETEG was established with the GT-power software and validated with the AETEG test bench. The heat exchangers with chaos shape and fishbone shape were proposed, their pressure drop with different engine speeds was studied, and their effects on the performance of both the AETEG and the ICE were analyzed. The results show that compared with the fishbone-shaped structure, the pressure drop of chaos-shaped heat exchanger is larger at the same engine speed, which contributes to the increased maximum power and hot side temperature of the AETEG. Moreover, compared with the ICE without heat exchanger, the brake torque, brake power, volumetric efficiency, pumping mean effective pressure, CO emission, and CO2 emission of the ICE assembled with chaos-shaped and fishbone-shaped heat exchanger reduce, and the corresponding brake-specific fuel consumption increase because of the raised backpressure caused by the heat exchanger.

Model predictive control of a dual fuel engine integrated with waste heat recovery used for electric power in buildings

AbstractWaste heat recovery (WHR) system uses the thermal energy from the exhaust gases of an internal combustion engine (ICE) to assist in the electricity generated by the ICE generator in buildings. This paper presents a model predictive control (MPC) framework to minimize the fuel consumption of an ICE by integrating it with a WHR system. To this end, a control oriented model of a WHR system is developed and then integrated to a control oriented model of a turbocharged dual fuel diesel‐natural gas ICE. The ICE model is derived based on experimental data collected from a 6.7 L Cummins ISB engine modified for dual fuel operation. The designed MPC framework optimizes the ICE combustion, turbocharger, and organic Rankine cycle (ORC) system in the WHR to minimize fuel consumption of the ICE. The designed control framework also allows to meet time‐varying exhaust gas temperature requirements of the ICE to meet exhaust emission constraints. The results show that the optimal operation of the WHR and the ICE reduces the fuel consumption of the ICE by 6.7%.

An intelligent energy management strategy for an off‐road plug‐in hybrid electric tractor based on farm operation recognition

Due to the growing emergence of vehicle electrification, agricultural tractor developers are launching hybrid powertrains in which energy management strategy (EMS) assumes a prominent role. This work mainly aims at developing an EMS for a plug-in hybrid electric tractor (PHET) to minimise fuel consumption and increase the operating range. The developed off-road PHET power sources are composed of a biogas-fuelled Internal Combustion Engine Generator (Bio-Gen), a photovoltaic system, and a battery pack. To control the power flow among different sources, a two-layer EMS is formulated. In this regard, initially, the farm operating mode is recognised by means of classification of a working cycle's features. Then, a control strategy based on a multi-mode fuzzy logic controller (MFLC) is employed to manage the power flow. At each sequence, the classifier identifies the farm operation condition and accordingly activates the relative mode of the MFLC to meet the requested power from the Bio-Gen. The performance of the proposed EMS has been evaluated based on three real-world typical agricultural working cycles. The results demonstrate the successful performance of the proposed intelligent EMS under farm conditions by maintaining the energy sources' operation in a high-efficiency zone which can lead to the extension of the working range and decrease fuel consumption.

1D energy, exergy, and performance assessment of turbocharged diesel/hydrogen RCCI engine at different levels of diesel, hydrogen, compressor pressure ratio, and combustion duration

There is a growing concern about the feasibility of a new generation of internal combustion engines in a low-temperature and efficient way that can meet the emission regulations while maintaining the desirable power performance. This requires the controllability and flexibility over the ignition and reactivity within the cylinder by handling two fuels with different chemical reaction intensity. In this research, the reactivity controlled compression ignition (RCCI) turbocharger-assisted engine is proposed that operates with diesel-hydrogen fuels. After calibration and model validation, the effect of pressure ratio of compressor in turbocharger, hydrogen energy share, diesel mass per cycle, and combustion duration on temperature rise, entropy, pressure, heat release, and engine performance is evaluated. The design variables effects on the exergy share of work, heat, exhaust loss, irreversibility, and exergetic performance coefficient (EPC) are assessed and analyzed. Increasing the compressor pressure ratio can significantly increase the engine power and reduce fuel consumption. It is proved that turbocharging can reduce the entropy generation and thereby reduce irreversibility. The lower diesel injection is favored in terms of the work exergy and the EPC.

The Effects of Ultra-Low Viscosity Engine Oil on Mechanical Efficiency and Fuel Economy

The development of a sustainable powertrain requires improved thermal efficiency. Reducing frictional power losses through the use of ultra-low viscosity oil is one of the most effective and economical ways. To assess the potential for efficiency enhancement in a new generation of future engines using low-viscosity oils, a technical analysis was conducted based on numerical simulation and theoretical analysis. This study proposes a numerical method coupling the whole multi-dynamics model and lubrication model under mixed lubrication regimes. Then, load distribution was calculated numerically and verified experimentally. Finally, this paper compares the bearing load and frictional energy loss of the main bearings when using The Society of Automotive Engineers (SAE) 15W40 and SAE 0W20 oil. The results indicate that the application of ultralow-viscosity lubricant can reduce the hydraulic friction loss up to 24%, but the asperity friction loss would increase due to the reduction in load capacity. As a result, the design of a new generation of high efficiency internal combustion engines requires careful calculation and design to balance the trade-off relations between hydraulic friction and asperity friction.

Validation of a LES Spark-Ignition Model (GLIM) for Highly-Diluted Mixtures in a Closed Volume Combustion Vessel

<div class="section abstract"><div class="htmlview paragraph">The establishment of highly-diluted combustion strategies is one of the major challenges that the next generation of sustainable internal combustion engines must face. The desirable use of high EGR rates and of lean mixtures clashes with the tolerable combustion stability. To this aim, the development of numerical models able to reproduce the degree of combustion variability is crucial to allow the virtual exploration and optimization of a wide number of innovative combustion strategies.</div><div class="htmlview paragraph">In this study ignition experiments using a conventional coil system are carried out in a closed volume combustion vessel with side-oriented flow generated by a speed-controlled fan. Acquisitions for four combinations of premixed propane/air mixture quality (Φ=0.9,1.2), dilution rate (20%-30%) and lateral flow velocity (1-5 m/s) are used to assess the modelling capabilities of a newly developed spark-ignition model for large-eddy simulation (GLIM, GruMo-UniMORE LES Ignition Model). The model accounts for all the main physical phenomena governing flame kernel growth, including electric circuit and over-adiabatic thermal expansion, which are included in the LES formalism of ECFM-LES combustion model. In the first part of the study the agreement of the simulation results against measurements is carried out to assess a validated non-reacting condition and converged flow statistics. Then, combustion simulations are carried out, and ignition events are repeated at random timings to replicate flow variability at ignition. Finally, optical comparison is carried out for simulated enflamed volume against high-frequency Schlieren images for all the cases, and measurements of flame radius growth are presented. The agreement of the quantitative flame measurements, as well as the qualitative resemblance of flame development, indicate the use of the presented GLIM ignition model as a valuable model for multi-cycle engine simulations, with particular relevance on unstable and CCV-affected conditions</div></div>

Thermo-economic analysis and optimization of ICE-ORC systems based on a splitter regulation

The traditional Organic Rankine Cycle (ORC) system recovering waste heat from Internal Combustion Engine (ICE) ignores the low-grade thermal energy of jacket cooling water. In this paper, a new ICE-ORC configuration is proposed to maximize the ORC net power output for different ICE rated power outputs. The comparative analysis between the ICE-ORC system based on a splitter regulation and two traditional ICE-ORCs is presented with ten different working fluids. The computational results demonstrate whether it is necessary to recover jacket cooling water waste heat with different working fluids, and cascade utilization of exhaust gas and jacket water waste heat by splitter regulation is validated with different Caterpillar series of ICE. Moreover, using pentane as working fluid has the best performance which ORC power output is 556 kW for all the three different ICE-ORC bottoming cycles and ten working fluids, and the ICE-ORC bottoming cycle efficiency is increased by 17% compared with single ICE generator set. This research provides information to increase the efficiency and power output of ICE-ORC configuration modification and determines the direction of further improvement.

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Life cycle assessment and comparative exergoenvironmental evaluation of a micro-trigeneration system

The cascading use of energy distinguishes trigeneration systems from simple heat recovery strategies and conventional separate electric and thermal energy systems. Small-scale trigeneration is referred to as micro-trigeneration, and is a potentially sustainable energy solution. Despite the demonstrated benefits from economic, energy, and environmental perspectives, the adoption of micro-trigeneration systems has been undoubtedly underexplored in the tertiary sector. This study presents a detailed Life Cycle Assessment for a natural gas-fueled micro-trigeneration system, encompassing the equipment and energy flows. Two endpoint environmental assessment methods were employed, the Eco-indicator 99 and ReCiPe. The environmental data was utilized to develop exergoenvironmental assessments. The specific environmental impact for both methods, despite presenting different absolute values, show the same behavior. The highest environmental impacts are found at the internal combustion engine and steam generator. Regarding the evaluation of exergoenvironmental parameters, the absorber heat exchanger and steam generator should be the focus of improvement efforts. This study contributes to improving the understanding of which processes within a micro-trigeneration system contribute the most to exergy destruction and generation of environmental impacts.

Measuring Automotive Exhaust Particles Down to 10 nm

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;The latest generation of internal combustion engines may emit significant levels of sub-23 nm particles. The main objective of the Horizon 2020 “DownToTen” project was to develop a robust methodology and provide policy recommendations towards the particle number (PN) emissions measurements in the sub-23 nm region. In order to achieve this target, a new portable exhaust particle sampling system (PEPS) was developed, being capable of measuring exhaust particles down to at least 10 nm under real-world conditions. The main design target was to build a system that is compatible with current PMP requirements and is characterized by minimized losses in the sub-23 nm region, high robustness against artefacts and high flexibility in terms of different PN modes investigation, i.e. non-volatile, volatile and secondary particles. This measurement setup was used for the evaluation of particle emissions from the latest technology engine and powertrain technologies (including vehicles from other Horizon 2020 projects), different fuel types, and a wide range of exhaust aftertreatment systems. Results revealed that in most cases (non-volatile), PN emissions down to 10 nm (SPN&lt;sub&gt;10&lt;/sub&gt;) do not exceed the current SPN&lt;sub&gt;23&lt;/sub&gt; limit of 6×10&lt;sup&gt;11&lt;/sup&gt; p/km. However, there are some cases where SPN&lt;sub&gt;10&lt;/sub&gt; emissions exceeded the limit, although SPN&lt;sub&gt;23&lt;/sub&gt; were below that. An interesting finding was that even in the latter cases, the installation of a particle filter could significantly reduce PN emissions across a wide particle size range, fuels, and combustion technology. DownToTen results are being used to scientifically underpin the Euro 7/VII emission standard development in the EU. The method developed and the results obtained may be used to bring in the market clean and efficient vehicle technologies, improve engine and emission control performance with different fuels, and characterize size-fractionated particle chemistry to identify the formation mechanisms and control those in a targeted, cost-effective fashion.&lt;/div&gt;&lt;/div&gt;

Development of a Eulerian Multi-Fluid Solver for Dense Spray Applications in OpenFOAM

The new generation of internal combustion engines is facing various research challenges which often include modern fuels and different operating modes. A robust modeling framework is essential for predicting the dynamic behavior of such complex phenomena. In this article, the implementation, verification, and validation of a Eulerian multi-fluid model for spray applications within the OpenFOAM toolbox are presented. Due to its open-source nature and broad-spectrum of available libraries and solvers, OpenFOAM is an ideal platform for academic research. The proposed work utilizes advanced interfacial momentum transfer models to capture the behavior of deforming droplets at a high phase fraction. Furthermore, the WAVE breakup model is employed for the transfer of mass from larger to smaller droplet classes. The work gives detailed instructions regarding the numerical implementation, with a dedicated section dealing with the implementation of the breakup model within the Eulerian multi-fluid formulation. During the verification analysis, the model proved to give stable and consistent results in terms of the selected number of droplet classes and the selected spatial and temporal resolution. In the validation section, the capability of the developed model to predict the dynamic behavior of non-evaporating sprays is presented. It was confirmed that the developed framework could be used as a stable foundation for future fuel spray modeling.

Prospects, progress, challenges and policies for clean power generation from biomass resources

Worldwide primary energy needs are satisfied basically from non-renewable sources that are limited in supply and innately hazardous to the environment. Biomass-based power systems are very much potent to address the environmental issues fostering sustainable development, while being able to provide a secured and uninterrupted power supply at the same time. Biomass-based power generation systems not only reduce the GHG emissions but also have enormous opportunities of job creation and promote biomass re-growth through sustainable land management practices. This paper overviews the biomass scenario in Southeast Asian and EU countries to give an overview of the potential and scalable energy harnessed from biomass resources. Economic analyses presented on biomass gasification-based power generation have been evaluated with three specific cost estimations, namely low, average and high. Key economic performance metrics of biomass gasification-based dual-fuel internal combustion engine generator with low investment estimates are as follows: a positive net present value of USD 7.5 million; internal rate of return 14.45%; and a payback period of 5.45 years. A review of the technologies can provide a base for strategic energy policy for the next generation of sustainable energy policies and helps policymakers to frame strategies aiming for clean technology and sustainable development. Biomass integrated gasification combined cycle-based systems are found to be most suitable for power generation or biofuel synthesis.

Review of recent advances of free-piston internal combustion engine linear generator

Free piston internal combustion engine linear generator (FPELG) is a novel energy conversion device. Compared with traditional rotary internal combustion engines, FPELG shows many potential advantages due to the elimination of crank-connecting rod mechanism, such as structure simply, the high thermal efficiency, the low emission, the multi-fuel and the multi combustion mode feasibility. Therefore, the FPELG has become a research hot-point in recent years and has achieved a lot of research results. This paper mainly discusses and summarizes the recent technical advances of the FPELG from the research groups worldwide. After a brief introduction on the early research of the free-piston internal combustion engines, its working principle and different configurations are introduced respectively. Then, this paper mainly focuses on the recent research progress of the FPELG from the aspects of modeling and simulation method, experimental approach, and control strategies development. In the end of the paper, the research trend and future development of the FPELG will be prospected. It is concluded that matching and optimizing performances of free-piston internal combustion engine and linear generator are the key research points, and the controlled piston trajectory of the FPELG is the key technology.

Experimental Investigation of Bioenergy Production from Small-Scale Gasification of Landfill-Diverted Wood Wastes

Small-scale biomass gasification systems integrated with internal combustion engines can be a solution to the dual challenges of reducing greenhouse gas emissions from electricity production and reducing waste sent to landfills; however, these systems are typically designed for high-value, virgin wood chip feedstocks. This investigation aims to improve the feasibility of this technology by exploring the use of landfill diverted wood wastes (construction and demolition waste, used pallets and oriented strand board) in place of costly wood chips for the production of bioenergy in a pilot scale gasifier combined with an internal combustion engine generator operating at 10 kWe. The effect of feedstock bulk properties on gasifier operational stability and process parameters, including magnitude and variability of temperature and pressure drop, are investigated. Low bulk density ( 55°) increased system instability through the formation and collapse of bridges and channels in the gasifier. Tar and particulate matter in the producer gas are quantified, as well as removal efficiencies of the gas clean-up for different feedstocks. Tar concentration in the syngas was in the range of 1.2 to 5.2 g/m3 downstream of gas clean-up, and was found to increase with system instability parameters and feedstock moisture. Finally, over the range of feedstocks examined in this study, a novel empirical correlation was developed to describe tar production from the gasifier as a function of feedstock bulk properties. The relationship between feedstock bulk properties and tar production is a unique finding and can enable to development of reliable waste-to-energy gasification systems.

Energetic macroscopic representation and inversion based control of fuel cell in a series hybrid race vehicle system

This paper studies the replacement of engine and generator as range extender in a hybrid racing car with a fuel cell system. A model of the original system of the car using range extender consisting of an internal combustion engine and electric generator has been developed respecting the action-reaction principle used by energetic macroscopic representation (EMR) and its inversion based control (IBC) to organise its subsystems interconnection according to the physical causality. Results from drive tests of the real car on racing circuit are used to validate the model. The objective of this paper is to study the parameterisation and the integration of fuel cell stack components based on this model. First diagnosis on applicability of a control strategy as well as the improvements that can be effected by implementing a fuel cell system can be obtained using this model.