Hybrid Propulsion Research Articles

Bridging the Technology Gap: Strategies for Hybrid Rocket Engines

Hybrid rocket propulsion, first demonstrated by the Russian GIRD-09 rocket in 1933, combines liquid oxidizer and solid fuel for thrust generation. Despite numerous advantages, such as enhanced safety, controllability, and potential environmental benefits, hybrid propulsion has yet to achieve its full potential in space applications. In recent years, the research on hybrid propulsion has gained enormous momentum in both academia and industry. Recent accomplishments such as the altitude record for student rockets (64 km), the launch of the first electric pump-fed hybrid rocket, and a successful 25 s hovering test highlight the potential of hybrid rockets. However, although the hybrid community is growing constantly, industrial utilizations and in-space validations do not yet exist. In this work, we reassess the possibilities of hybrid rocket engines by presenting potential fields of applications from the literature. Most importantly, we identify the technical challenges that hinder the breakthrough of hybrid propulsion in the space sector and evaluate the technologies and approaches necessary to bridge the gaps in hybrid rocket development.

Synergies and Trade-Offs in Hybrid Propulsion Systems Through Physics-Based Electrical Component Modeling

Abstract Hybrid-electric propulsion is recognized as an enabling technology for reducing aviation's environmental impact. In this work, a serial/parallel hybrid configuration of a 19-passenger commuter aircraft is investigated. Two underwing-mounted turboprop engines are connected to electrical branches via generators. One rear fuselage-mounted electrically driven ducted fan is coupled with an electric motor and respective electrical branch. A battery system completes the selected architecture. Consistency in modeling accuracy of propulsion systems is aimed for by development of an integrated framework. A multipoint synthesis scheme for the gas turbine and electric fan is combined with physics-based analytical modeling for electrical components. Influence of turbomachinery and electrical power system design points on the integrated power system is examined. An opposing trend between electrical and conventional powertrain mass is driven by electric fan design power. Power system efficiency improvements in the order of 2% favor high-power electric fan designs. A trade-off in electrical power system mass and performance arises from oversizing of electrical components for load manipulation. Branch efficiency improvements of up to 3% imply potential to achieve battery mass reduction due to fewer transmission losses. A threshold system voltage of 1 kV, yielding 32% mass reduction of electrical branches and performance improvements of 1–2%, is identified. This work sets the foundation for interpreting mission-level electrification outcomes that are driven by interactions on the integrated power system. Areas of conflicting interests and synergistic opportunities are highlighted for optimal conceptual design of hybrid powertrains.

A power-speed hierarchical optimization framework of diesel/battery/supercapacitor vehicular hybrid propulsion systems

Ships' fuel consumption has emerged as the primary contributor to energy use and pollution in maritime transportation. This paper presents a novel marine vehicular hybrid propulsion system (VHPS) comprising a diesel generator and a hybrid energy storage device (HESD) that integrates batteries and supercapacitors (SCs). However, variations in the power and energy characteristics of the three sources result in heightened intricacies in energy management and system control. Therefore, a power-speed hierarchical optimization framework is proposed to optimize the fuel consumption and stability of the system. Within this framework, an AECMS-GRNN energy management strategy (EMS) is proposed to reduce the fuel consumption of VHPS. Based on the AECMS-GRNN strategy's power distribution results, a multi-zone target speed power hysteresis control strategy is proposed to ensure that the speed of the diesel generator is stable, so as to improve the stability of the system. Finally, an experimental hardware-in-the-loop (HIL) platform is employed to validate the proposed framework's performance. From experimental results, the AECMS-GRNN strategy demonstrates precise load prediction with a minimal predictive ARMSE value of 1.5886 kW. Compared with a conventional rule-based (RB) strategy, AECMS-GRNN strategy can reduce the fuel consumption by 0.077 kg, about 7.7%. Additionally, the proposed speed control strategy ensures a stable speed for the DG, contributing to the system's consistent power supply.

Techno–economic analysis of fuel cell powered urban air mobility system

This study verified the technological and economic feasibility of converting urban air mobility (UAM) to a fuel cell–battery hybrid propulsion system from an existing battery–only propulsion system. The battery–fuel cell hybrid propulsion UAM was conceptually designed through reverse engineering and redesigned of the existing battery–only propulsion UAM. Under various design conditions, the economic feasibility of the hybrid propulsion system was verified through life cycle cost (LCC) analysis. Hybrid propulsion UAMs designed with appropriate hybridization ratios had 10% lower life cycle costs than battery-only propulsion UAMs. In particular, this cost–saving effect was more noticeable when UAM's flight distance became longer. The life cycle cost increased proportionally as the number of UAM passengers increased, but was relatively unrelated to energy storage technology improvements. Considering the current electricity and hydrogen price changes, the economic feasibility of fuel cell–battery hybrid UAM is expected to continue to improve in the future compared to batteries alone.

A digital twin approach for maritime carbon intensity evaluation accounting for operational and environmental uncertainty

Maritime industry has set ambitious goals to drastically reduce its greenhouse gas emissions through stipulating and enforcing a number of energy assessment measures. Unfortunately, measures like the EEDI, EEXI, SEEMP and CII do not account for the operational and environmental uncertainty of operations at sea, even though they do provide a first means of evaluating the carbon footprint of ships. The increasing availability of high-frequency operational data offers the opportunity to quantify and account for this uncertainty in energy performance predictions. Current methods to evaluate and predict energy performance at a whole energy system level do not sufficiently account for operational and environmental uncertainty. In this work, we propose a digital twin that accurately predicts the fuel consumption and carbon footprint of the hybrid propulsion system of an Ocean-going Patrol Vessel (OPV) of the Royal Netherlands Navy under the aggregate effect of operational and environmental uncertainty. It combines first-principle steady-state models with machine learning algorithms to reach an accuracy of less than 5% MAPE on both mechanical and electrical propulsion, while bringing a 40% to 50% improvement over a model that does not utilise machine learning algorithms. Results over actual voyage intervals indicate a prediction accuracy of consumed fuel and carbon intensity within 2.5% accounting for a confidence interval of 95%. Finally, the direct comparison between mechanical and electrical propulsion showed no clear energy-saving benefits and a strong dependency of the results on each voyage’s specific operational and environmental conditions.

THE CONCEPT OF ELECTRONIC CONTROL UNIT FOR COMBUSTION ENGINE IN HYBRID TANDEM

The article presents the concept of a hybrid propulsion unit for ultralight aircraft. A combustion unit and an electric motor/generator were presented. As part of the research, a dedicated combustion engine controller and a two-way converter for energy conversion were built. The prototype drive unit was installed on a test stand and its initial characteristics were determined. The results of research and conclusions related to the construction of a hybrid drive unit are presented.

Sustainable operation? Measuring the actual consumption of a hybrid car and determining its consumption curve

Sustainability is one of the most commonly used terms concerning renewable energy, environmental protection and energy management. Without a doubt, understanding its full meaning, it is clear that sustainability is paramount for the quality of life of future generations and for the Earth as a living space. The presented work aims to give an overview of the importance of on-board management in hybrid vehicles as an important tool to increase their contribution to sustainable mobility. Real-world condition measurements were carried out based on the available cognitive features of an average vehicle. Several main consumers were also tested to present their role within cognitive and sustainable mobility. Results show that there is a function between the battery load level and the hybrid vehicle electric power use likeliness. Among the primary but under-addressed concerns today are the uninhibited exploitation of non-renewable energy sources and the avoidance of pollution.

A review of methods to improve power transmission for energy efficiency of both electric and hybrid vehicle

In recent years, many optimization methods have been raised to deal with the fuel and cost efficiency problems of the new generation cars. This study reviews two primary optimization methods, one for pure electric cars and one for hybrid vehicles, with detailed explanations. For electric vehicles, methods for designing electric powertrains that are energy efficient while sustaining vehicle dynamics and ride quality are discussed. The three characteristics of energy consumption, dynamic performance, and ride comfort are optimized using modeling, and the final optimization method is determined, which can achieve a 93.5% improvement in lightweight and a 92% improvement in power transmission. Four standard powertrain transmissions are mentioned for hybrid vehicles with advantages and limitations. The most promising multimode information is selected to work with a single EM instead of the dual EMs that conventional hybrid cars contain. The simulation results of the single-EM HEV with the MMT model and its comparison test with the "THS II-LIke'' vehicle, holding the same parameters except having dual EMs, show the well-performance of this method in energy loss. In the end, a more efficient engine, the Atkinson engine, for hybrid vehicles is illustrated to substitute the traditional otto cycle engine.

The perspective of hybrid electric hydrogen propulsion systems

Electric cars are becoming increasingly popular, with the European Union and the United States administrations committed to making their share overwhelming by the end of this decade. In analogy, electric powerboats and aircraft are also being proposed. Here we show as hybrid electric vehicles (HEVs) have advantages vs. battery-only electric vehicles (BEVs) for all these applications. Adopting a hybrid propulsion system based on storing most of the energy in hydrogen, and producing electricity on board through a fuel cell (FC) stack, or an internal combustion engine (ICE) plus a generator, gives a much better techno-economic perspective, and reduced life cycle analysis CO2 emissions, than the use of huge lithium-ion batteries. An HEV having plug-in capability and a relatively small battery permits pure electric operation on short travel, without the burden of huge batteries to deliver range. The battery of the HEV buffers the upstream hybrid generation system, which may recharge the battery and/or power directly the electric motor, and store the braking energy in ground vehicles. HEVs fuel energy storage and onboard electricity generation on demand permit reduced total mass of the propulsion system for the same design range as huge batteries. HEVs with ICE working on hydrogen offers the minimum total mass of the propulsion system, then HEVs with FC. This assessment is correct for the current liquid electrolyte batteries and the near-future solid-state electrolyte batteries, based on their energy density per unit mass, and the indirect emissions of batteries.

Optical signatures of Förster-induced energy transfer in organic/TMD heterostructures

Hybrid van der Waals heterostructures of organic semiconductors and transition metal dichalcogenides (TMDs) are promising candidates for various optoelectronic devices, such as solar cells and biosensors. Energy-transfer processes in these materials are crucial for the efficiency of such devices, yet they are poorly understood. In this work, we develop a fully microscopic theory describing the effect of the Förster interaction on exciton dynamics and optics in a WSe2/tetracene heterostack. We demonstrate that the differential absorption and time-resolved photoluminescence can be used to track the real-time evolution of excitons. We predict a strongly unidirectional energy transfer from the organic to the TMD layer. Furthermore, we explore the role temperature has in activating the Förster transfer and find a good agreement to previous experiments. Our results provide a blueprint to tune the light-harvesting efficiency through temperature, molecular orientation and interlayer separation in TMD/organic heterostructures.

Enhancing photocatalytic degradation efficiency via the construction of organic/inorganic S-scheme supramolecular hybrid heterostructures

This study demonstrates the successful construction of a hybrid van der Waals heterostructure (vdWH) consisting of 3D supramolecular networks and 2D semiconductor Ag3PO4, using hydrogen-bonded 3D networks H12SubPcB-OPh2OH self-assembled onto Ag3PO4. The resulting organic/inorganic vdWH exhibits significantly enhanced photocatalytic degradation efficiency for oxytetracycline (OTC) and tetracycline (TC) under visible light irradiation, with apparent rate constants 1.8 and 1.5 times higher than those of pristine Ag3PO4, respectively. Moreover, after five photocatalytic cycles, the photocatalytic activity of vdWH was still much higher than that of pristine Ag3PO4. Molecular dynamics simulations indicate that the SubPc-3 supramolecular assembly is more prone to forming a 3D hydrogen bonding network rather than a 1D columnar stacking. In-situ irradiated X-ray photoelectron spectroscopy analyses and theoretical calculations confirm that the charge transfers between H12SubPcB-OPh2OH and Ag3PO4 are consistent with the S-scheme mechanism. This work provides a promising strategy for designing and fabricating efficient and stable supramolecular self-assembled semiconductor-based photocatalysts.

Investigation on energy management strategy of gas-electric marine hybrid propulsion system with improved dynamic programing algorithm

An energy management strategy (EMS) is important in marine hybrid propulsion systems while the global optimal solutions are more significant for the EMS to improve the fuel economy of system. Aiming at finding the more accurate global optimal solutions for EMS, an improved dynamic programing (DP) algorithm was proposed to overcome the basic DP algorithms’ weaknesses and improve the fuel economy. Then the model of gas-electric hybrid propulsion system was also established to verify the strategies. What’s more, the improved DP algorithm was applied to the minimum natural gas consumption and charge-sustaining strategy. And a bi-level optimization scheme that decoupled the interaction between the EMS and components matching was also studied. The results showed that the improved DP algorithm not only avoided the shortcomings in the basic DP algorithm such as the weak effect of penalty functions and curse of dimensionality but also gave more accurate solutions. Compared to the basic DP, the improved DP algorithm can reduce the gas fuel consumption by 3.67% and the computational complexity decreases 100 times.

A death due to faulty airbag system-case report.

Injuries due to automobile safety devices have been reported and we report a rare fatality due to a defective airbag system. A compact hybrid car driven by a 37-year-old male at moderate speed had crashed through an unprotected manhole. The car had moved around 200m before it came to a halt. The passers-by had noticed that the driver was unconscious, partly leaning forward with an inflated airbag. He was pronounced dead on admission. The car had sustained minor indentation on front bumper. Autopsy revealed a circular perforated laceration on the neck associated with completely transected right carotid artery and partially transected jugular vein. There was a 2 × 2-cm cylindrical metal object lodged at C4-C5 vertebrae level, and the remaining part of this was retrieved during scene investigation and identified as a part of a metal canister in the inflator component of the airbag system. There was a perforation in the airbag which was similar in size to the retrieved foreign body. The cause of death was ascertained as hemorrhagic shock due to bleeding from ruptured neck vessels caused by primary shrapnel projected from the faulty airbag system. Following the incident, the manufacturers replaced faulty airbag systems in similar models. If abnormally fatal injuries are observed, a scene visit along with automotive expert opinion would provide valuable insight into the incident. Such information would alert the general public on regular screening of safety measures and prompt manufacturers to recall faulty products.

A multi-objective optimization energy management strategy for marine hybrid propulsion with waste heat recovery system

To improve the efficiency of marine hybrid propulsion systems (HPS) and make full of the potential of the waste heat recovery system, this paper presents a powerplant scheme which includes marine HPS with thermoelectric generator (TEG) and organic rankine cycle (ORC) system. The original energy management strategy (EMS) based on the multi-objective optimization algorithm is proposed, which considers the objectives of minimum total energy consumption, maximum output energy of TEG and ORC, and the optimal engine efficiency. The EMS is validated with different initial states of charge of the battery, and the influence of weight factors in the EMS on the system performance is also investigated. Additionally, the interactions between various ship driving cycles and performance of TEG and ORC system are analyzed. Compared with the traditional engine propulsion, the maximum energy saving of the HPS is 13.74%, while the efficiency of the engine and ORC system has been improved by 1.53% and 1.17%, respectively. This paper provides a new algorithm of waste heat recovery system regulation and gives a valuable reference for EMS optimization in marine HPS.

A GRNN informed ECMS-ALPF operational management strategy for reducing fuel consumption of diesel/battery/supercapacitor hybrid vehicles

The fuel consumption and pollution emission of ships have become the main focuses in ocean environment management. This paper proposes a new marine vehicular hybrid propulsion system (VHPS), which is composed of a diesel generator and a hybrid energy storage system consisted of batteries and supercapacitors. However, the distinct power and energy characteristics of the three power sources result in complex operational management and a negative impact on energy conservation and emission reduction. Therefore, a general regression neural network informed equivalent consumption minimization strategy and adaptive low pass filter (GRNN informed ECMS-ALPF) operational management strategy (OMS) is proposed to optimize the fuel consumption and energy loss. Finally, a hardware in the loop experimental platform is utilized to verify the performance of proposed OMS. From experimental results, the GRNN informed ECMS-ALPF strategy has accurate load predictive capability, the predictive average root mean square error value is only 2.1633 kW, whose fuel consumption is 14.9% lower compared with a conventional rule-based strategy. And the energy loss of the given hybrid energy storage system can reduce 0.0178 kWh (about 14.55%) compared with a conventional low pass filter strategy. The proposed VHPS and OMS offer insights for the study of ocean and coastal management.

FIRE HAZARD OF HYBRID AND ELECTRICAND VEHICLES

In the following time, we received information from many countries of the world about accidents related to fires and explosions of motor vehicles with electric and hybrid vehicles. The popularity of such news is caused by the fact that accidents and fires of cars with internal combustion engines have long become commonplace, which do not attract the attention of the general public. However, many numerous and conducted scientific studies say about the danger of electric and hybrid vehicle models with lithium-ion batteries that they are greatly exaggerated, i.e., damage to the traction battery (battery) can cause a self-destructive chain reaction, but the degree the danger of electrolyte is less than that of gasoline or diesel fuel and much less than that of hydrogen fuel in hybrid modifications. The article examines the causes of the fire hazard of electric and hybrid cars and their consequences. Scientific reasons and innovations regarding the prevention and immediate elimination of short circuits, fires and explosions in the closed space of lithium-ion batteries during the operation of electric hybrid cars are provided. Electric vehicles and hybrids tend to suffer from traction battery technical and other issues. Although a battery flash is dangerous and more difficult to extinguish than a gas flash, the cause of the fire is usually different and these results are found in a defect in the battery pack: "ruptured anode" and "complex separator". The Hyundai Kona and Chevrolet Bolt EV had the most electric vehicle recalls related to fires this year, totaling 152,000 vehicles, while the top two hybrid recalls totaled more than 32,000 vehicles. A lithium-ion type of car catches fire usually not immediately, but after some time. This determines the driver and passengers to immediately leave the interior of the vehicle. When extinguishing a fire, there is a risk of damage to passengers, eyewitnesses and others who are near it by the electric current of high-voltage systems. It is recommended to get out of the interior of the car engulfed in fire and smoke in a timely manner and call the rescuers of the Ministry of Emergency Situations by calling the emergency service. The main task of the firefighters who arrived in the city at the first stage of the event was to disconnect the high-voltage cable using an emergency disconnector or mechanically and to disconnect the high-voltage traction battery. Although the risk of flash in EVs and hybrids exists, it may be receiving a disproportionate amount of attention. It is important for car manufacturers to eliminate the risk of ignition in their vehicles as much as possible, but obviously no form of driving is completely safe. Keywords: hybrid and electricand car, fire, explosion, lithium-ion battery.

Differential Analysis of GPX Traces on Historical and Recent Satellite Imagery

High Power rocketry had observed great achievement in past few decades. It has a large tailing of propulsion technologies which are not only effective but also sustainable. Among all the propulsion types, like the most widely used in earlier era, chemical propulsion, Electric propulsion had gained there roots in the field due to its advantages in performance and durability in space missions. In this paper we will be dealing with the types of electric propulsion arrangement and network with its potentiality applications. The paper starts from giving an insight of traditional propulsion ways, like chemical propulsion, which were commonly used in rockets. With which the key features of electric propulsion including electrostatic, electrothermal, electromagnetic and electrodynamic thrusters have been discussed. With witch the main working principles, features and applications are discussed. Also the limitations of earlier propulsion system like efficiency of fuel and thrust have been discussed. In addition to which the the challenges faced during the era of the change in electric propulsion have been discussed which will help us to get an intuition of the phase change. In this paper we can come across at the result which demonstrates the advantage of electric propulsion over the old methods of propulsion. The advantages of electric Propulsion like extended mission duration, which increase the efficiency of mission, and the expanded payload capacity which gives a wide range to mission portrait. To sumup with which we will find the advantages of electric propulsion over other types of propulsion, with the advantage of electric propulsion and its wide features which gives a lead to our missions. Keywords: propulsion systems, electric propulsion, high-powered rockets, Hall Effect thrusters, ion thrusters, Specific Impulse, hybrid propulsion, experimental validation, cost-benefit analysis, space applications.

Economic Analysis and the EEXI Reduction Potential of Parallel Hybrid Dual-Fuel Engine‒Fuel Cell Propulsion Systems for LNG Carriers

Abstract One potential solution for reducing carbon dioxide emissions from ships and meeting the Energy Efficiency Existing Ship Index (EEXI) requirements is to use a hybrid propulsion system that combines liquid hydrogen and liquefied natural gas fuels. To improve energy efficiency for diesel-electric dual-fuel ship propulsion systems, an engine power limitation system can also be used. This paper examines the potential use of these systems with regard to several factors, including compliance with EEXI standards set by the International Maritime Organization, fuel ratio optimisation, installation requirements, and economic feasibility. As a case study, an LNG carrier is analysed, with dual-fuel diesel-electric and two hybrid systems adjusted to meet IMO-EEXI requirements with engine power limitation percentages of 25%, 0% (hybrid option 1), and 15% (hybrid option 2), respectively. From an economic standpoint, the liquid hydrogen-based system has competitive costs compared to the dual-fuel diesel-electric system, with costs of 2.1 and 2.5 dollars per kilogram for hybrid system options 1 and 2, respectively.

Off-Design Performance Analysis of a Parallel Hybrid Electric Regional Turboprop Aircraft

Hybrid electric propulsion is one of the alternative solutions for reducing fuel burn and lower emissions while keeping a reasonable battery mass for regional turboprop aircraft operating on short routes. Most studies reporting fuel burn reductions evaluate the aircraft on the design mission, although regional transport aircraft rarely operate under these conditions. Therefore, considering its off-design performance is essential for providing a more complete understanding of aircraft capabilities under various operating conditions. Under these flight conditions, the multi-energy management aspect of hybrid propulsion and the fixed size of the batteries could have a significant impact on the system robustness in off-design operation. In this study, the off-design performance of an existing regional turboprop aircraft retrofitted with a parallel hybrid electric powertrain is assessed. Fuel burn benefits are evaluated on the payload–range diagram for an initial hybrid design and compared to the baseline aircraft. Then, using a novel sizing approach, considering a typical mission operation, this study shows an average improvement of percentage point on fuel burn benefits relative to the initial hybrid aircraft, creating a more robust design.

Assessment of Na-Ion Battery Performance Using Machine Learning

In the last couple of decades, the smart design of battery electroactive materials and cells to satisfy the demand for efficient energy storage has attracted significant research interest. Li-ion batteries have been widely employed in hybrid cars, power plants, and electronic devices. However, sodium-ion batteries are getting increasing attention as sodium is much more earth-abundant and inexpensive than lithium. In this work, we studied the impact of critical materials and cell design factors, electrode preparation methods, and operational descriptors on the discharge capacity and the cycle life of the Na-ion batteries using machine learning. The dataset was created from 355 experimental papers published in 2015-2020 and contained 1227 different experiments: 747 and 380 cases had only the anode and the cathode studies, respectively, whereas 100 cases were for the full cells. In the analysis, 38 descriptors were used on the electrode materials, electrolyte, and electrode structure, in addition to material synthesis and electrode preparation methods. On the other hand, peak discharge capacity and cycle life (the highest cycle number at which 80% of the peak capacity is retained) were selected as the target (output) variables. Random forest, gradient boosting, support vector machines (for regression), and decision tree (for classification) methods were used for the analysis. In the analyses, the dataset was randomly divided into two subsets: 75% to build the models (training and validation) and 25% to test the performance of the models in predicting the unseen data. Five-fold cross-validation was applied for hyperparameter optimization. Root mean square error (RMSE) was calculated as the performance indicator.The pre-analysis of the dataset presented that the highest average discharge capacity is obtained with the alloy-based anodes, followed by metal sulfides. However, their average cycle life is relatively low. In contrast, carbon-based anodes present prolonged cycle life even though they have low discharge capacities. Moreover, full-cell applications that couple the alloy-based anodes with the metal oxide cathodes show the highest average discharge capacity. Lastly, for anode or cathode half-cell studies, using a single solvent leads to higher discharge capacities and cycle life. In contrast, mixed solvents perform better in full cells.Random forest models successfully predicted the discharge capacity and demonstrated the relative significance of descriptors (Figure 1). Boruta analysis, performed for feature importance, showed that the anode and cathode types are highly effective. At the same time, the synthesis method and crystal structure were also found to be influential. On the other hand, we used classification models, which can be considered as range prediction instead of point prediction, instead of regression models to analyze the cycle life data. Decision tree classification of cycle life was quite effective, leading to heuristic rules for selecting the anode and cathode materials or methods for synthesis and electrode preparation. Material synthesis conditions are essential for high cycle life for the anode, while solvent selection is also critical for the cathode studies. Figure 1. Random Forest Regression model for the prediction of the peak discharge capacity for a) anode training, b) anode testing, c) cathode training, and d) cathode testing sets