Hydrogen Internal Combustion Engine Research Articles

Optimization of the flame characteristics of H2–O2 coaxial injection applied to hydrogen-fueled argon cycle engines

The argon power cycle is one of the most promising technologies for high efficiency and low emission hydrogen-fueled internal combustion engines. The application of coaxial injection technology in the hydrogen-fueled argon engine can improve the mixing process and the combustion performance of the H2/O2 mixture. In this study, an innovative H2–O2 coaxial injection combustion system was designed to investigate the jet flame characteristics of oxygen coaxially wrapped by hydrogen in a controllable argon thermal atmosphere. The findings of this study could provide a new perspective for designing hydrogen-fueled argon engines in the future. The influences of co-flow temperature, jet injection pressure, and excess oxygen coefficient were all determined. Observations of the flame showed a bright blue flame with a reddish glow in the far-burner region. Experimental results show that the flame length, cross-sectional area, and area/perimeter ratio first decrease with increasing jet injection pressure and subsequently increase, reaching maximum values at 0.4–0.6 MPa. When increasing the co-flow temperature from 1023 K to 1223 K, the cross-sectional area of the flame increases significantly by 61.1% at an excess oxygen coefficient of 0.4. Furthermore, the liftoff flame height shrinks when the co-flow temperature and the excess oxygen coefficient increase, while it rises along with an increasing jet injection pressure.

Selective Catalytic Reduction of NOx with H2 for Cleaning Exhausts of Hydrogen Engines: Impact of H2O, O2, and NO/H2 Ratio

A key concept for hydrogen-fueled internal combustion engines is reducing NOₓ emissions with direct H₂-SCR. Besides platinum as an active noble metal component, palladium-based catalysts are attractive for NO reduction with high selectivity. However, reliability of the catalytic activity in the presence of water with persistently low side product formation remains challenging. Therefore, a monolithic 1%Pd/5%V₂O₅/20%TiO₂-Al₂O₃ model catalyst is studied extensively under different conditions, showing that NOₓ conversion remains high even in the presence of 5% water, maintaining over 65% selectivity toward N₂. Additionally, the catalyst remained active in a long-term experiment over 12 h in the absence and presence of water with an NO conversion over 45%. Finally, steady-state measurements and a kinetic analysis reveal overall concentration dependencies alongside trends of the reduction reaction competing with the hydrogen combustion reaction.

3D CFD simulation of a gaseous fuel injection in a hydrogen-fueled internal combustion engine

Nowadays, one of the hottest topic in the automotive engineering community is the reduction of fossil fuels. Hydrogen is an alternative energy source that is already providing clean, renewable, and efficient power being used in fuel cells. Despite being developed since a few decades, fuel cells are affected by several hurdles, the most impacting one being their cost per unit power. While waiting for their cost reduction and mass-market penetration, hydrogen-fueled internal combustion engines (H2ICEs) can be a rapidly applicable solution to reduce pollution caused by the combustion of fossil fuels. Such engines benefit from the advanced technology of modern internal combustion engines (ICEs) and the advantages related to hydrogen combustion, although some modifications are needed for conventional liquid-fueled engines to run on hydrogen. The gaseous injection of hydrogen directly into the combustion chamber is a challenge both for the designers and for the injection system suppliers. To reduce uncertainties, time, and development cost, computational fluid dynamics (CFD) tools appear extremely useful, since they can accurately predict mixture formation and combustion before the expensive production/testing phase. The high-pressure gaseous injection which takes place in Direct-Injected H2ICEs promotes a super-sonic flow with very high gradients in the zone between the bulk of the injected hydrogen and the flow already inside the combustion chamber. To develop a methodology for an accurate simulation of these phenomena, the SoPHy Engine of the Engine Combustion Network group (ECN) is used and presented. This engine is fed through a single nozzle H2-injector; planar laser-induced fluorescence (PLIF) data are available for comparison with the CFD outcomes.

A Numerical Exploration of Engine Combustion Using Toluene Reference Fuel and Hydrogen Mixtures

Hydrogen-fueled internal combustion engines (H2ICEs) are capable of operating over a wide range of equivalence ratios: from ultra-lean mode to stoichiometric conditions. However, they provide maximum thermal efficiency and minimum NOx emissions if operated lean. Although NOx is produced, H2ICEs generate little or no CO, CO2, SO2, HC, or PM emissions. The main limitation to pure hydrogen fueling is power density. To overcome such an issue, mixtures of gasoline and hydrogen can be exploited, with small modifications to the engine feeding system. Due to the peculiar characteristics of hydrogen (in terms of thermophysical properties, molecular weight and propagating flame characteristics) care must be adopted when trying to address combustion using computational fluid dynamics (CFD) tools. In this work, we simulate the combustion of mixtures of toluene reference fuel (TRF) and hydrogen under largely different ratios. To simplify the problem, liquid and gaseous injections are neglected, and a premixed mixture at the inlet of the CFD domain is imposed. Due to the different laminar flame speeds of the mixture components, mass-fraction weighted in-house correlations based on chemical kinetics simulations are adopted. Outcomes are compared with those obtained using standard correlations and mixing rules available in most commercial CFD packages.

Introduction of HCCI for Hydrogen Fuel Engines

This paper is a brief review of the homogeneous charge compression ignition (HCCI) model for hydrogen-fueled internal combustion engines based on an analysis of the advantages and disadvantages of hydrogen internal combustion engines and HCCI combustion. It found that HCCI can be realized in a hydrogen-fueled internal combustion engine, meanwhile the HCCI can effectively reduce the emission of hydrogen internal combustion engine.

Effect of supercharger system on power enhancement of hydrogen-fueled spark-ignition engine under low-load condition

Hydrogen energy has received much attention in recent years due to its reliability and non-carbon products. However, it has been found that the backfire phenomenon plays a major part in limiting power and torque in the hydrogen internal combustion engine (H2ICE). Much research in recent years has considered turbocharger as a useful method to improve the power of H2ICE. Although the result of boosting a system with turbocharger became enhanced when compared to the natural aspiration system. Unfortunately, there were unsolved problems in exhaust backpressure and pumping losses that hindering the practical utilisation of H2ICE. This paper investigated the experiment of 2.4 L supercharged port fuel injection engine at 2000 rpm. Air excess ratio (lambda) was varied from stoichiometric to 2.8 by adjusting the boosting amount in supercharger, and throttling of the air. The hydrogen injection amount were maintained the same with turbocharger condition; spark advance timing was set at maximum brake torque. It was observed that by boosting engine with supercharger, the lower pumping loss and higher indicated mean pressure had been obtained when compared to turbocharger boosted engine under low-load condition. However, some additional power required for supercharging that lowers output of the engine.

A perspective on the use of ammonia as a clean fuel: Challenges and solutions

A perspective on the use of ammonia as a clean fuel: Challenges and solutions

Numerical study of hydrogen addition on the performance and emission characteristics of compressed natural gas spark-ignition engine using response surface methodology and multi-objective desirability approach

Today, the demand for higher output efficiencies, lower fuel consumption, and ever reduced emissions has been rising. Due to its availability, one promising alternative is the applying of hydrogen in internal combustion engines. In this study, the initial efforts concentrated on combine relationships of input and output parameters of hydrogen compressed natural gas spark-ignition engine. The quadratic regression models were conducted for all six responses: torque, carbon monoxide, brake-specific fuel consumption, methane, nitrogen oxides, and total hydrocarbon through response surface methodology and tested for adequacy by analysis of variance. The multi-objective desirability approach employed for the optimization of input variables, namely, the hydrogen compressed natural gas ratio, excess air ratio ( λ), and ignition timing ( θi). Also, two factors, that is, manifold absolute pressure and engine speed, were fixed at 105 kPa and 1600 r/min, respectively. Results indicate that the optimal independent input factors are equal to λ of 1.178, hydrogen compressed natural gas ratio of 25.98%, and θi of 18 °CA before top dead center. Also, the optimal combination of responses is as follows: brake-specific fuel consumption of 219.334 g/kWh, the torque of 395 N m, 30.189 g/kWh for nitrogen oxides, carbon monoxide equal to 5.093 g/kWh, total hydrocarbon of 0.633 g/kWh, and 0.572 g/kWh for methane. This study provided the significance of response surface methodology as an attractive technique for investigators for modeling. In this regard, the response surface methodology modeling and multi-objective desirability approach can be utilized to predict the emission and performance characteristics of the hydrogen compressed natural gas engines minutely.

Conceptual Approach on Feasible Hydrogen Contents for Retrofit of CNG to HCNG under Heavy-Duty Spark Ignition Engine at Low-to-Middle Speed Ranges

Hydrogen-based engines are progressively becoming more important with the increasing utilization of hydrogen and layouts (e.g., onboard reforming systems) in internal combustion engines. To investigate the possibility of HICE (hydrogen fueled internal combustion engine), such as an engine with an onboard reforming system, which is introduced as recent technologies, various operating areas and parameters should be considered to obtain feasible hydrogen contents itself. In this study, a virtual hydrogen-added compressed natural gas (HCNG) model is built from a modified 11-L CNG (Compressed Natural Gas) engine, and a response surface model is derived through a parametric study via the Latin hypercube sampling method. Based on the results, performance and emission trends relative to hydrogen in the HCNG engine system are suggested. The operating conditions are 1000, 1300, and 1500 rpm under full load. For the Latin hypercube sampling method, the dominant variables include spark timing, excess air ratio (i.e., λCH4+H2), and H2 addition. Under target operating conditions of 1000, 1300, and 1500 rpm, the addition of 6–10% hydrogen enables the virtual HCNG engine to reach similar levels of torque and BSFC (brake specific fuel consumption) compared to same lambda condition of λCH4. For the relatively low 1000 rpm speed under conditions similar to those of the base engine, NOx formation is greater than base engine condition, while a similar NOx level can be maintained under the middle speed range (1300 and 1500 rpm) despite hydrogen addition. Upon addition of 6–10% hydrogen under the middle speed operation range, the target engine achieves performance and emission similar to those of the base engine.

Short communication: The effects of not controlling the hydrogen supplied to an internal combustion engine

Recent research works have focused on analyzing the performance of the hydrogen-fueled internal combustion engines. In this short communication, we present the results of using hydrogen-enriched gasoline in an internal combustion engine without modifying the fuel control algorithm. For this purpose, two different analyses are presented and experimentally validated. In the first analysis, the internal combustion engine is fueled with hydrogen-enriched gasoline using the engine electronic control unit. On the other hand, the second analysis uses this fuel (gasoline + H2), and a control scheme based on model predictive control with constraints considering the hydrogen ratio. The experimental results showed that by using the engine electronic control unit, the gasoline consumption increases by 7.18%. And using the model predictive control, gasoline consumption can be reduced by 2.2%.

Electric Vehicles Batteries: Requirements and Challenges

Jie Deng is a research engineer in the Department of Electrification Subsystems and Power Supply at Ford Motor Company. He has extensive experience in computer-aided engineering analysis (structural, fluid, and thermal), battery simulations, and material characterization. He got his PhD in Mechanical Engineering from Florida State University and has published over 30 papers. His current research mainly focuses on battery array design and multi-physics modeling and testing of battery behaviors under various abuse conditions. Chulheung Bae is a high-voltage battery systems group supervisor at Ford Motor Company, where his research activities focus on lithium ion battery system development and validation for automotive applications. Dr. Bae has over 22 years of experience in advanced battery materials and various energy storage devices, including Lithium Ion, NiZn, Lead-Acid and redox flow batteries, and ultra-Capacitors. Dr. Bae has a Doctorate in Chemical Engineering from University of Manchester in the UK. Adam Denlinger is manager of high-voltage systems research and development at Ford Motor Company. Adam’s team is responsible for delivering high-voltage battery system innovations—including packaging, durability, thermal, management and controls, and EMC—as well as human-centered technologies targeting an enhanced electrified vehicle ownership experience. The team also leads multiple collaborations in this field with industry, university, and national lab partners. Adam has worked with Ford for 22 years, with experience delivering powertrain technologies, including Ford’s first Ecoboost engine application, industry-first hydrogen internal combustion engine vehicle fleet, and multiple high-voltage battery systems for battery electric (BEV) and plug-in electric (PHEV) vehicles. Ted Miller is manager of electrification subsystems and power supply research. His team is responsible for Ford global electrification subsystem and power supply research, delivering battery system design innovations in advanced cell technology, packaging, thermal, EDS, EMC, charging, power conversion, and energy management and modeling. They provide subject matter expertise from raw materials to end-of-life recycling. The team also leads collaboration with university, industrial, and National Lab partners. Mr. Miller is chairman of the United States Advanced Battery Consortium and a member of the Idaho National Laboratory Strategic Advisory Committee and the University of Michigan Energy Institute External Advisory Board.

Effect of excess hydrogen on hydrogen fueled internal combustion engine under full load

Detailed hydrogen-air chemical reaction mechanisms were coupled with three dimension grids of an experimental hydrogen fueled internal combustion engine (HICE) to establish a combustion model based on CONVERGE software. The influence of excess hydrogen coefficient on the combustion and emission characteristics of HICE under full load was studied based on the CFD model. Simulation results showed that excess hydrogen leaded to higher concentration of OH species in flame front, and quicker hydrogen-oxygen reaction and flame propagation speed, which in turn leaded to higher pressure and temperature in cylinder. The rise of pressure and temperature in turn contributed to the increase of indicate power but un-burned hydrogen leaded to decrease of efficiency. NOx, especially NO emissions decreased significantly with excess hydrogen under full load not only because increased of H concentration, and decreased of O and OH concentration, which leaded to reverse reaction of NO formation through thermal NO routes. Low excess hydrogen coefficient can achieve a good trade-off between power and emissions under full load.

Progress on the studies about NOx emission in PFI-H2ICE

Owing to its brilliant combustion performance and cleanest combustion products, hydrogen has been widely considered as one best alternative fuel for internal combustion engines. However, in the cylinder of hydrogen internal combustion engines, high combustion temperature and oxygen enrichment make NOx is still one but the only combustion pollutant. Therefore, it is particularly important to control NOx emission for hydrogen fuelled engines. Since PFI-H2ICE (port-fuel-injection hydrogen internal combustion engine) is the normal type of hydrogen fuelled engines, the present article will focus on the studies about NOx emission in PFI-H2ICE researches. First, the present article reviews the mechanism of NOx generation in PFI-H2ICE; upon chemical kinetics, the generation of NOx will be summarized and discussed into three major paths which including thermal NO path, NNH–NO path and N2O–NO path. Then, the researches on the control methods of NOx for PFI-H2ICE in recent years will be systematically reviewed, the influencing factors to reduce NOx emission will be summarized in some aspects which including combustion component control strategy, injection control strategy, ignition control strategy and engine compression ratio control strategy. To the PFI-H2ICE operated at lean fuel conditions (like equivalence ratio is less than 0.5) or rich fuel conditions (like equivalence ratio is higher than 1), the technologies and the strategies of EGR (exhaust gas re-circulation) will be reviewed and discussed. It is hoped this literature review would enable researchers to systematically understand the progress of NOx emissions research in PFI-H2ICE and explore further research directions.

Simulation and experimental study of the NOx reduction by unburned H2 in TWC for a hydrogen engine

The unburned H2 can be used to reduce NO emission in conventional TWC (three-way catalyst) for a hydrogen internal combustion engine when it works at equivalence ratio marginally higher than the stoichiometric ratio. To explore the effects and feasibility of this reaction, a Perfectly Stirred Reactor simulation model of TWC has been built with simplified mechanisms. Experiments on a 2.3 L turbocharged hydrogen engine are used to verify the conclusion. It shows that rising initial temperature accelerates the reduction of NO and the maximum reaction rate occurs at 400 °C temperature. The conversion efficiency of NO remains approximately 0 when temperatures below 300 °C. The efficiency reaches a peak value of approximately 98% with 400 °C and declines gradually. The unburned H2 to NO mixing ratio greater than 1.5 in TWC guarantees 100% NO conversion efficiency. The experiments indicate that the NOx concentration decreases from 2056 ppm to 41 ppm at the stoichiometric ratio after the treatment of TWC and NOx reaches 0 ppm with a rich ratio. Results also demonstrate that the suitable reaction temperatures for TWC locate in the range of 400 °C–500 °C. Therefore, if the temperature and the mixing ratio are appropriate, it can achieve zero emissions with NOx reduction by unburned H2 in conventional TWC for a hydrogen engine.

Sıvı hidrojenli taşıtlar için yardımcı bir klima sistemi

Current Vehicle Air Conditioning (VAC) systems, which are operated by compressors driven by Internal Combustion Engines (ICEs) or batteries, increase the fuel consumption and emissions depending on the thermal load of the vehicle passenger cabin. Since decreasing the thermal load of the vehicle will decrease the fuel consumption and emissions, studies in this area is very important from the economic and environmental aspects. In this study, an Auxiliary Air Conditioning (AAC) system for Internal Combustion Engine Vehicles (ICEVs) or Fuel Cell Vehicles (FCVs) that store Liquid Hydrogen (LH2) as a powering source has been proposed to make contribution to the works in this significant area. ICEVs were evaluated as Gasoline Equivalent Hydrogen Internal Combustion Engine Vehicles (GEHICEVs) and Diesel Equivalent Hydrogen Internal Combustion Engine Vehicles (DEHICEVs) considering their average fuel consumption rates according to the New European Driving Cycle (NEDC). According to the analyses, approximate hydrogen consumption values have been found that reach 0.7 g/s for GEHICEVs, 1.6 g/s for DEHICEVs, and 0.6 g/s for FCVs with maximum cooling rates of 326 W, 704 W, and 250 W, respectively.

Power Improvement and NOx Reduction Strategies for a Hydrogen-Fueled Multicylinder Internal Combustion Engine

Abstract The conventional operation of a hydrogen internal combustion engine (ICE) under lean conditions results in low NOx emissions, however, at the cost of power generated. In this study, the power output of a hydrogen-fueled ICE was increased while maintaining the NOx emissions at low levels. The power output was increased by turbocharging, relatively richer operation, and spark timing optimization, whereas a combination of exhaust gas recirculation (EGR) and H2-selective catalytic reduction (H2-SCR) aftertreatment was used to reduce NOx emissions. Turbocharging resulted in a maximum torque output of 168 N·m at 3200 rpm as compared to 70 N·m at 1600 rpm for the naturally aspirated operation. However, the turbocharger could not generate enough boost at low speeds and the equivalence ratio was increased to obtain a high power output which resulted in a substantial increase in the NOx emissions. The use of EGR resulted in an average reduction of 72% in the NOx emissions. Retarding of spark timing significantly reduced the NOx emissions too, but was limited by the adverse impact on the torque. Since hydrogen would be available onboard a hydrogen-fueled vehicle, we for the first time report external injection of H2 for use as a reductant in the selective catalytic reduction unit. Even under extremely oxidizing conditions, the efficiency of aftertreatment was found to be 35.4% averaged over various speeds. A maximum of 83.7% overall reduction in NOx emissions was achieved by using the combined EGR and H2-SCR strategies.

The effect of engine speed and cylinder-to-cylinder variations on backfire in a hydrogen-fueled internal combustion engine

The port-injection-type hydrogen engine is advantaged in that hydrogen gas is injected into the intake pipe through a low-pressure fuel injector, and the mixing period with air is sufficient to produce uniform mixing, improving the thermal efficiency. A drawback is that the flame backfires in the intake manifold, reducing the engine output because the amount of intake air is reduced, owing to the large volume of hydrogen. Here, the backfire mechanism as a part of the development of full-load output capability is investigated, and a 2.4-liter reciprocating gasoline engine is modified to a hydrogen engine with a hydrogen supply system. To secure the stability and output performance of the hydrogen engine, the excess air ratio was controlled with a universal engine control unit.The torque, excess air ratio, hydrogen fuel, and intake air flow rate changes in time were compared under low- and high-engine speed conditions with a wide-open throttle. The excess air ratio depends on the change in the fuel amount when the throttle is completely opened, and excess air ratio increase leads to fuel/air-mixture dilution by the surplus air in the cylinder. As the engine speed increases, the maximum torque decreases because the excess air ratio continues to increase due to the occurrence of the backfire. The exhaust gas temperature also increases, except at an engine speed of 6000 rpm. Furthermore, the increase in exhaust gas temperature affects the backfire occurrence. At 2000 rpm, under low-speed and wide-open throttle conditions, backfire first occurs in the No. 4 cylinder because the mixture is heated by the relatively high port temperature. In contrast, at 6000 rpm, under high-speed and wide-open throttle conditions, the backfire starts at the No. 2 cylinder first because of a higher exhaust gas temperature, resulting in a lower excess air ratio in cylinders 2 and 3, located at the center of the engine.

Effect of Valve Timing and Excess Air Ratio on Torque in Hydrogen-Fueled Internal Combustion Engine for UAV

In this study, in order to convert a 2.4 L reciprocating gasoline engine into a hydrogen engine an experimental device for supplying hydrogen fuel was installed. Additionally, an injector that is capable of supplying the hydrogen fuel was installed. The basic combustion characteristics, including torque, were investigated by driving the engine with a universal engine control unit. To achieve stable combustion and maximize output, the intake and exhaust valve opening times were changed and the excess air ratio of the mixture was controlled. The changes in the torque, excess air ratio, hydrogen fuel, and intake airflow rate, were compared under low engine speed and high load (wide open throttle) operating conditions without throttling. As the intake valve opening time advanced at a certain excess air ratio, the intake air amount and torque increased. When the opening time of the exhaust valve was retarded, the intake airflow rate and torque decreased. The torque and thermal efficiency decreased when the opening time of the intake and exhaust valve advanced excessively. The change of the mixture condition’s excess air ratio did not influence the tendency of the torque variation when the exhaust valve opening time and torque increased, and when the mixture became richer and the intake valve opening time was fixed. Under a condition that was more retarded than the 332 CAD condition, the torque decreased by about 2 Nm with the 5 CAD of intake valve opening time retards. The maximum torque of 138.1 Nm was obtained at an optimized intake and the exhaust valve opening time was 327 crank angle degree (CAD) and 161 CAD, respectively, when the excess air ratio was 1.14 and the backfire was suppressed. Backfire occurred because of the temperature increase in the combustion chamber rather than because of the change in the fuel distribution under the rich mixture condition, where the other combustion control factors were constantly fixed from a three-dimensional (3D) computational fluid dynamics (CFD) code simulation.

Development and Assessment of a Novel Integrated System Using an Ammonia Internal Combustion Engine and Fuel Cells for Cogeneration Purposes

In this study, a novel ammonia-based integrated system, incorporating both ammonia- and hydrogen-fueled internal combustion engine and ammonia fuel cell system, is developed for cogeneration of pow...

HİDROKSİ GAZ ÜRETİMİNDE YENİ BİR KONTROL TEKNOLOJİSİ

The main idea of this study is to design an optimum oxyhydrogen production algorithm for user-defined internal combustion engine volume. It is a scientifically proven fact that the use of hydrogen in internal combustion engines is beneficial to performance and emissions until a certain limit. Although improvements in performance and emissions have been reported by researchers; the designed control system offers an option to approach the highest achievable efficiency for hydroxy usage in compression ignition engines. The system allows improving efficiency with instantaneous calculations and feedback algorithm of HHO production rate and enrichment amount. Automated HHO system designed to operate between 0-30 amperes range and relatively less operating temperatures to prolong the service life of engine batteries and HHO generator.