Conventional Combustion Engine Research Articles

Hydrogen Fuel-cell Technology in Electric Vehicles: Current Usage, Materials and Future Applications

A conventional combustion engine results in high greenhouse gas emissions, so the world is transforming to clean energy and electric vehicles. Developments and applications of hydrogen fuel cells in electric vehicles (EVs) lead the world toward a sustainable future. Hydrogen fuel applies to fuel cells and generates electricity through electrochemical reactions. It is exceptionally clean because the by-products are water and heat, so there has no visual pollution from vehicles. HFC technology is not commonly used for now but will take place in many EVs. Some countries planned to apply it to electric power systems, railways and spacecraft fields. Currently, HFC uses platinum as the main catalyst material because of its stability, high efficiency, and good performance that boosts the hydrogen and oxygen reactions. It is the most reliable source and a perfect catalyst that is widely applied. Other catalysts such as carbon-coated nickel, nitrogen-carbon mixtures (MNCs) and transition metal nitrides (TMNs) all show good performance and have similar efficiency with Pt. These materials could replace platinum in the future because Pt has limited sources and higher costs. Also, the study has found that scientists use ruthenium graphene as a catalyst in hydrogen fuel cells. However, its effectiveness needs long-term monitoring. Although HFC is a clean technology, it has disadvantages, for example, hard for hydrogen extraction and storage, lacking refueling systems etc. Current technology limits development, and barriers exist, such as overwhelming H2 storage and delivery and some safety issues. Even so, hydrogen energy and HFC application are the future for EVs and others.

Cool flame wave propagation in high-pressure spray flames

Cool flame has an important impact on the performance and emission of advanced low-temperature combustion (LTC) internal combustion engines (ICEs) in which the liquid fuel is injected earlier at a lower ambient temperature (Tam) than that in the conventional diesel combustion engines. However, the cool flame characteristics of spray combustion under ICEs conditions are not fully understood, e.g., the effect of cool flame on the spray ignition and flame stabilization is not well studied. In this paper, the so-called cool flame wave propagation (CFWP) in the Engine Combustion Networks Spray A flames at three ambient temperatures Tam (800 K, 900 K and 1000 K) is analyzed using the data from large eddy simulation with an improved Eulerian based transported probability density function sub-grid combustion model. A good agreement between the LES results and experimental data is obtained for the spray liquid penetration length, vapor fuel penetration length, mean pressure rise profile, and flame liftoff length. It is shown that CFWP in the spray ignition process promotes the ignition of the fuel-rich and cold reactant mixture, leading to the most reactive mixture shifting toward fuel-richer locations due to the spatial stratification of temperature and concentration, and turbulent mixing. As a result, the high temperature ignition (HTI) can be shortened compared to the ignition in the homogeneous mixture. At Tam = 800 K, the HTI kernels are consistently formed following the CFWP propagating toward the spray head region. However, as Tam increases, the spatial correlation between HTI kernels and CFWP fronts is weakened. On the other hand, the turbulent mixing (quantified using local scalar dissipation rate) contributes more to the formation of HTI kernels at higher Tam. The present results indicate that CFWP is more profound at lower Tam in the spray ignition process. Finally, it is found that cool flame propagates mainly into pre-reacted fuel-rich mixture in an ignition wave propagation mode from the spray upstream region toward downstream region, whereas the ignition assisted flame mode is found in the spray upstream region where the combustion heat release is negligible.

Comparative life cycle assessment of conventional combustion engine vehicle, battery electric vehicle and fuel cell electric vehicle in Nepal

Battery electric vehicles (BEV) and Fuel cell electric vehicles (FCEV) are taking momentum as an alternative to conventional internal combustion engine vehicles (ICEV). Prospects of clean transportation and congruence with zero tailpipe emission are principal reasons for the adornment of these alternate technologies. This study aims to examine the collateral environmental impacts (GHG-100) that come alongside the production, use phase and end-life of ICEV, BEV and FCEV in the present context of Nepal. The current study uses a Cradle to Grave approach to compare the life cycle assessments (LCA) of Hyundai Tucson (2021), Hyundai Kona Electric 2021, and Hyundai Nexo Blue 2021 manufactured in South Korea (SK). Similarly, the LCA is performed under future scenarios of surplus electricity in Nepal and advancements in technologies. The results show that with the current import of 32% electricity from India, BEV and FCEV have 187- and 922-g total carbon dioxide equivalent (gCO2-eq) greenhouse gas (GHG) emission per kilometer respectively, which is 507 gCO2-eq/km for ICEV under the 200,000 km lifetime assumption of vehicles. The upstream emission for both the BEV and FCEV is poised to decrease by 88% with the surplus electricity scenario in Nepal, reducing 82% of the total emission of FCEV and 50% of BEV contributing to a cleaner local and global environment. Electricity sources significantly affect GHG emissions in both the production and use phases. Use of renewable electricity sources, and improvement in battery and fuel cell technologies reducing vehicle production supply chain impact with sharpened guidelines and policies regarding e-mobility, BEV and FCEV present themselves as promising alternative transportation technologies.

System analysis and requirements derivation of a hydrogen-electric aircraft powertrain

In contrast to sustainable aviation fuels for use in conventional combustion engines, hydrogen-electric powertrains constitute a fundamentally novel approach that requires extensive effort from various engineering disciplines. A transient system analysis has been applied to a 500 kW shaft-power-class powertrain. The model was fed with high-level system requirements to gain a fundamental understanding of the interaction between sub-systems and components. Transient effects, such as delays in pressure build up, heat transfer and valve operation, substantially impact the safe and continuous operation of the propulsion system throughout a typical mission profile, which is based on the Daher TBM850. The lumped-parameters network solver provides results quickly, which are used to derive requirements for subsystems and components, which support their in-depth future development. E.g. heat exchanger transfer rates and pressure drop of the motor's novel hydrogen cooling system are established. Furthermore, improvements to the system architecture, such as a compartmentalization of the tank, are identified.

Computational study of the multi-injector isobaric combustion concept in a heavy-duty compression ignition engine

• A multi-injector concept on an isobaric combustion engine was studied. • Two side injectors led to less flame-piston interactions. • Good fuel flexibility was achieved using multi-injection strategies. • Larger nozzle number and wider inner piston yielded higher efficiencies. • A lower intake temperature was effective in reducing the heat transfer loss. Compared to the conventional diesel combustion engine that is equipped with a single centrally installed injector, the multi-injector spray-combustion concept has the potential to achieve higher thermal efficiency. In this work, a numerical study to explore the combustion characteristics of the multi-injector concept on an isobaric combustion compression ignition engine was conducted. The simulation results reveal that, compared to the single-injector case, a significantly lower heat transfer loss was induced using two side injectors owing to the less intense flame-piston interaction. In addition, good fuel flexibility was achieved using multiple injections, which was attributed to the initially generated hot regions downstream of the injection trajectory. To further optimize the engine combustion performance, the effects of several major design parameters such as the injector location and rotation angle, hole number and gap angle, spray angle, and piston geometry were investigated. The results showed that the spray/flame-wall interaction had a significant effect on the development of combustion heat release. Various design parameters showed a significant impact on the combustion heat release during the late combustion period when an intense flame-wall interaction was occurring. To attain a better engine performance, the injector location and nozzle design should be adequately adjusted according to the inner piston radius and depth. The reduction of intake temperature and introduction of an appropriate amount of isochoric combustion process were found to further promote the engine work, making it possible to achieve a thermal efficiency of over 50%.

Detailed analysis of particulate emissions of a multi-cylinder dual-mode dual-fuel engine operating with diesel and gasoline

Internal combustion engines are still within the future of highway transport. Low-temperature combustion modes are prone to substitute conventional diesel combustion engines, seeking better performance and improved emissions control. The dual-mode dual-fuel combustion approach has been confirmed as a feasible combustion mode for achieving ultra-low NOx and soot emissions simultaneously. The aim of this work is to experimentally measure the particle emissions of the dual-mode dual-fuel concept while maintaining good thermal efficiency and EURO VI engine-out NOx levels. A detailed analysis of the most relevant characteristics of the particle size distribution is carried out to depict the requirements of a potential filtering system considering the effects of an upstream diesel oxidation catalyst. The results show that total particle numbering is within the typical values of the current most popular technologies: around 2·1013 #/kWh for RCCI and around 1014 #/kWh for DMDF. RCCI combustion tends to produce more particles sized below 35 nm in diameter, while DMDF shows a clear dominance of sizes above 40 nm. In terms of total particulate matter, RCCI results in total mass concentrations around 4 mg/kWh thanks to the highly premixed combustion, but diffusive combustion mode results in total mass emissions over 50 mg/kWh.

Application of ORC to reduce the energy penalty of carbon capture in non-stationary ICE

The electrification of productive activities cannot be considered the only strategy for a low-carbon economy, and sectors such as road freight and passenger transport will have to continue using technologies based on combustion in the medium and long term. It is expected that sustainable synthetic fuels and CO2 capture and storage technologies (CCS) can help to reduce greenhouse emissions. However, the occupation of spaces and the energy penalty of the capture are handicapped in smaller facilities, such as conventional combustion engine vehicles, and determine its technical and economic viability. In this paper, AVL boost and Aspen + softwares simulations are performed to analyze the feasibility of using an Organic Rankine Cycle (ORC) to supply the power consumption of an on-board CCS system coupled to an internal combustion engine (ICE) operating at partial engine loads and over the whole rpm range. Two spark-ignition engines of different sizes, fueled with CH4, have been modelled, and temperature swing adsorption is selected as a viable method for the CCS system, assuming a carbon capture rate of 90 %. Results show that the ORC reduces between 3.9 and 13.9 % the penalization of the CCS system over the engine power, keeping it under 8.84 % in the small engine and 5.71 % in the large engine. It can be concluded that an ORC-CCS hybridized system is energy feasible for the operation of an ICE working at partial loads in the entire rpm.

Evaluation of electric vehicle power technologies: Integration of technological performance and market preference

The evolution in vehicle power technologies from the combustion engine to hybrid or pure electric vehicles requires automakers to mobilize organizational capability and change operational patterns. Aside from the incumbent conventional combustion engines, hybrids, plug-in hybrids, and pure electric vehicles of various engineering designs are currently competing as future technological alternatives. This research develops a technology evaluation model which incorporates technological factors and market criteria to facilitate decision making for allocating resources to various renewable power technologies for passenger vehicles. Using the Analytical Hierarchy Process (AHP), the technology evaluation model was quantified by experts and consumers by ranking the relative performance of Lithium-Ion batteries, Fuel Cells, and Hybrid technologies. Expert quantification ranks these technological alternatives in order of technological performance, while consumer evaluation prioritizes user preferences. Demographic factors were used to classify consumer groups and variations in technological preferences between consumer groups were examined. The results show that Li-Ion technology has advantages in terms of purchasing cost, operating cost, and refuel facilities, while Fuel Cells outperform Li-Ion in terms of driving range, battery life, and refuel time. The environmental concern criterion is ranked first in the consumer evaluation result and is specifically preferred by high-income respondents and luxury car owners. The research bridges the characteristics of technological alternatives with market preferences, and its results facilitate the management decision in choosing the promising future technology.

The multi-field coupling effect of fuel injection duration on gas exchange stability for a free piston engine generator

• The detailed process of fuel injection duration affected the gas exchange stability through multi-field coupling effect was revealed. • Increasing the fuel injection duration is beneficial to improve scavenging efficiency, and the maximum scavenging efficiency is 97.9%. • Shortening the fuel injection duration is beneficial to improve the trapping efficiency, and the maximum trapping efficiency is 41.3%. • The afterburning effect and the backflow phenomenon were found. • The EGR mass fraction is inversely proportional to the fuel injection duration. Free piston engine generator (FPEG) is a new energy conversion plant to substitute for conventional combustion engine. However, the fluctuation of gas exchange is a key problem to induce the FPEG to run unsteadily and restrict its engineering application. This paper presents a study to explore the multi-field coupling effect of fuel injection duration on the gas exchange stability of a diesel compression-ignition, direct-injection, looped scavenging FPEG. A full-cycle gas exchange model of the FPEG is carried out by coupling the zero-dimensional dynamics, multi-dimensional combustion model and scavenging model, and an iterative calculation method is proposed for numerical simulation of the model. Meanwhile, the effect of injection duration schedule lasting from 0.50 ms to 0.80 ms on the scavenging and gas exchange is analyzed. The results show that the shorter injection duration brings about higher fresh trapping efficiency due to its faster reciprocating frequency which reduces the available time for fresh gas to flow out of the cylinder during gas exchange process, and the trapping efficiency is 41.3 % and the operating frequency achieves 36.6 Hz in the injection duration of 0.5 ms condition. However, the influence of injection duration on exhaust gas cleaning is opposite, and the scavenging efficiency varies in positive correlation with the injection duration, because the long injection leads to low motion velocity and causes the exhaust port to be opened and closed slowly, which provides long exhaust time of the residual burned gas in the cylinder. The maximum scavenging efficiency occurs in the injection duration of 0.8 ms condition and features with 97.9%. Suggesting, relatively high scavenging efficiency and trapping efficiency can be obtained at the same time under appropriate injection duration condition.

A review of internal combustion engines powered by renewable energy based on ethanol fuel and HCCI technology

<abstract> <p>In general, as compared to conventional combustion engines, the homogeneous charge compression ignition (HCCI) engine offers better fuel efficiency, NOx, and particulate matter emissions. The HCCI engine, on the other hand, is not connected to the spark plugs or the fuel injection system. This implies that the auto-ignition time and following combustion phase of the HCCI engine are not controlled directly. The HCCI engine will be confined to a short working range due to the cold start, high-pressure rate, combustion noise, and even knocking combustion. Biofuel innovation, such as ethanol-powered HCCI engines, has a lot of promise in today's car industry. As a result, efforts must be made to improve the distinctive characteristics of the engine by turning the engine settings to different ethanol mixtures. This study examines the aspects of ethanol-fueled HCCI engines utilizing homogenous charge preparation procedures. In addition, comparing HCCI engines to other advanced combustion engines revealed their increased importance and prospective consequences. Furthermore, the challenges of transitioning from conventional to HCCI engines are examined, along with potential answers for future upgrade approaches and control tactics.</p> </abstract>

A review of internal combustion engines powered by renewable energy based on ethanol fuel and HCCI technology

<abstract> <p>In general, as compared to conventional combustion engines, the homogeneous charge compression ignition (HCCI) engine offers better fuel efficiency, NOx, and particulate matter emissions. The HCCI engine, on the other hand, is not connected to the spark plugs or the fuel injection system. This implies that the auto-ignition time and following combustion phase of the HCCI engine are not controlled directly. The HCCI engine will be confined to a short working range due to the cold start, high-pressure rate, combustion noise, and even knocking combustion. Biofuel innovation, such as ethanol-powered HCCI engines, has a lot of promise in today's car industry. As a result, efforts must be made to improve the distinctive characteristics of the engine by turning the engine settings to different ethanol mixtures. This study examines the aspects of ethanol-fueled HCCI engines utilizing homogenous charge preparation procedures. In addition, comparing HCCI engines to other advanced combustion engines revealed their increased importance and prospective consequences. Furthermore, the challenges of transitioning from conventional to HCCI engines are examined, along with potential answers for future upgrade approaches and control tactics.</p> </abstract>

Computational comparison of the conventional diesel and hydrogen direct-injection compression-ignition combustion engines

Most research and development on hydrogen (H2) internal combustion engines focus on premixed-charge spark ignition (SI) or diesel-hydrogen dual-fuel technologies. Premixed charge limits the engine efficiency, power density, and safety, while diesel injections give rise to CO2 and particulate emissions. This paper demonstrates a non-premixed compression-ignition (CI) neat H2 engine concept that uses H2 pilots for ignition. It compares the CI H2 engine to an equivalent diesel engine to draw fundamental insights about the mixing and combustion processes. The Converge computational fluid dynamics solver is used for all simulations. The results show that the brake thermal efficiency of the CI H2 engine is comparable or higher than diesel, and the molar expansion with H2 injections at TDC constitutes 5–10 % of the total useful work. Fuel-air mixing in the free-jet phase of combustion is substantially higher with H2 due to hydrogen’s gaseous state, low density, high injection velocity, and transient vortices, which contribute to the 3 times higher air entrainment into the quasi-steady-state jet regions. However, the H2 jet momentum is up to 4 times lower than for diesel, which leads to not only ineffective momentum-driven global mixing but also reduced heat transfer losses with H2. The short H2 flame quenching distance may also be inconsequential for heat transfer in CI engines. Finally, this research enables future improvements in CI H2 engine efficiency by hypothesizing a new optimization path, which maximizes the free-jet phase of combustion, hence is totally different from that for conventional diesel engines.

A Numerical Study of a Compressed Air Engine with Rotating Cylinders

This article explores the possibility that, during the elimination of conventional combustion engines, the connecting rod becomes deflected. A larger connecting rod angle creates higher lateral pressure on the piston, also leading to greater loads on other engine components. This fact inspired us to develop an applied mechanism design that reduces the disadvantages of conventional combustion engines. The presented mathematical model that describes the designed engine working principle was created utilizing Lagrange’s equations of motion of the second kind and solved in MATLAB. This paper also includes a multibody simulation model of the engine mechanism created using the Simpack software. Based on a comparison of the two methods, the obtained waveforms of the selected kinematic quantities were found to yield minimal deviations. A real prototype was subsequently developed based on the mathematical model outputs. In this manner, we practically verified that the proposed theoretical solution for a non-conventional engine is fully functional.

Gas Containment Systems for Stationary and Mobile Applications

While green hydrogen production should remain the main target toward Zero Emissions Society, it would be prudent to maximize the utilization of easily accessible energy carries available already today in abundance.Compressed Natural Gas (CNG) represents a widely available energy carrier. Approximately 4.000 CNG/LNG car filling stations are available, thus enabling CNG to be used as fuel for commercial and personal vehicles based on the SOFC technology. Employing SOFC up to 30% higher efficiency can be achieved in comparison with conventional combustion engines. The SOFC based vehicles fueled by CNG can thus represent a perfect intermediate solution toward CO2 reduction and elimination of NOx emissions. Decentral power and heat generation via SOFC in combination with CNG offers yet another pathway to reach CO2 targets set by the European Union. Conditions for continued, more rapid growth of SOFC technology are favorable as global demand seeks different clean emissions heat and power generation solutions. Worthington as a center of excellence is focused on the design and production of high-pressure cylinders and onboard fueling systems for mobile applications, like vehicle integration, gas transport containers and stationary storage solutions. Ensuring easier fuel storage and transport, application and commercialization of SOFC based systems for mobile application can be accelerated.Worthington Industries is a global value-added steel processing company with headquarters in Columbus, Ohio, USA and production sites in Austria, Poland, and Portugal dedicated to pressure cylinder solutions for sustainable mobility. In addition to an overview of our approach to advancement of SOFC utilization, we intend to cover, as well, the availability of gas street components, system integration, safety, maintenance and product lifetime of proposed onboard fueling systems.

Free Stream Behavior of Hydrogen Released from a Fluidic Oscillating Nozzle

The H2 internal combustion engine (ICE) is a key technology for complete decarbonization of the transport sector. To match or exceed the power density of conventional combustion engines, H2 direct injection (DI) is essential. Therefore, new injector concepts that meet the requirements of a H2 operation have to be developed. The macroscopic free stream behavior of H2 released from an innovative fluidic oscillating nozzle is investigated and compared with that of a conventional multi-hole nozzle. This work consists of H2 flow measurements and injection tests in a constant volume chamber using the Schlieren method and is accompanied by a LES simulation. The results show that an oscillating H2 free stream has a higher penetration velocity than the individual jets of a multi-hole nozzle. This behavior can be used to inject H2 far into the combustion chamber in the vertical direction while the piston is still near bottom dead center. As soon as the oscillation of the H2 free stream starts, the spray angle increases and therefore H2 is also distributed in the horizontal direction. In this phase of the injection process, spray angles comparable to those of a multi-hole nozzle are achieved. This behavior has a positive effect on H2 homogenization, which is desirable for the combustion process.

Evaluation of reactivity controlled compression ignition mode combustion engine using mineral diesel/gasoline fuel pair

Stricter emission norms, scarce availability of conventional fuel resources, and moderate engine efficiency are primary concerns for both spark ignition (SI) and compression ignition (CI) engines. The use of advanced low-temperature combustion technologies can resolve these issues, amongst which reactivity-controlled compression ignition (RCCI) mode combustion has emerged as an important one. RCCI mode combustion exhibits significantly lower exhaust emissions (oxides of nitrogen [NOx] and particulate matter [PM]) compared to CI mode combustion and delivers higher BTE compared to SI mode combustion. In this study, RCCI mode combustion has been investigated in a single-cylinder research engine using gasoline and mineral diesel as low reactivity fuel (LRF) and high reactivity fuel (HRF), respectively. Experiments have been performed at different premixed ratios of LRF (premixed ratio [rp] = 0, 0.25, 0.50, and 0.75) and four-engine loads (1 bar to 4 bar BMEP) at a constant engine speed of 1500 rpm. The use of gasoline in RCCI mode combustion resulted in relatively smoother RCCI mode combustion compared to baseline CI mode combustion. The presence of low reactivity gasoline led to a slightly retarded start of combustion (SoC) and combustion phasing (CP), which improved the performance of the RCCI mode combustion engine. RCCI mode combustion produced relatively lower NOx emissions compared to baseline CI mode combustion. However, hydrocarbon (HC) and carbon monoxide (CO) emissions from RCCI mode combustion were significantly higher than the CI mode combustion. Lower PM emissions from RCCI mode combustion was an important observation of this investigation. Qualitative correlations between different parameters such as PM number and mass-size distributions, total particulate mass (TPM)-NOx, etc., revealed that RCCI mode combustion was capable of simultaneous reduction of NOx and PM, which is otherwise difficult in conventional CI mode combustion engines

Electric and plug-in hybrid vehicles and their infrastructure in a particular European region

As vehicles powered by conventional combustion engines must be refueled with fossil fuels, so electric vehicles need to supply their own source of energy needed to power them. In case of electric vehicles, electric energy is the main commodity, which is stored in batteries. Electric energy for electric vehicle (or some kinds of hybrid vehicles) is most often supplied by home electric charging station or public charging station. If we want to discuss advantages of operation of electric vehicles, we have to analyze the way of production of electric energy. If the vast majority of electricity produced in less ecological ways, which burden and pollute the environment, electric vehicles cannot be claimed as an environmentally friendly alternative and a substitute for internal combustion vehicles. There are also issues with charging options, building infrastructure, recycling used batteries and many others factors effecting future modes of transport. The article analyses the current overview of possibilities of charging electric or plug-in hybrid vehicles, current infrastructure aimed mainly on region of Central and Eastern.

Potential applications of additive manufacturing technologies in the vehicle industry

One of the most competitive fields on the planet is the automotive industry. Newmarket and innovative designs regularly arise, necessitating the development of new manufacturing methods to keep up with the automotive industry. Additive manufacturing offers a significant competitive advantage in this industry, serving as a disruptive strategy by increasing production flexibility, reducing product development time, and providing optimal automotive components and bespoke vehicle products on demand. Additive manufacturing on soft assembly tools or specialised tools to make automotive components enhances automotive production. Additive Manufacturing’s freeform capability allows for the design and direct fabrication of optimised automotive components aimed at improving vehicle performance, as well as tailored assembly tools to boost productivity. Another related technological advantage of additive manufacturing is the ability to create lightweight components with the help of generative design algorithms. Furthermore, the time to market for Additive Manufacturing parts has fallen dramatically, allowing mass customisation to become a reality. The strong downward trend in fuel consumption offers new automobile design, performance, and compliance with regulations. Considering the actual example switch from the conventional combustion engine to other motion systems, Additive Manufacturing is a critical enabler technology for modern automobiles. This paper provides an overview of Additive Manufacturing applications in the automobile sector, focusing on the technical and economic benefits of this manufacturing technology.

Effect of Global Fuel Starvation on Reversal Tolerant Anode Materials – Pulsed Versus Continuous Cell Reversal Events

A broad scientific consensus exists that anthropogenic emissions are major factors fueling global warming and its potential impacts on the earth’s ecosystem. On the way to a sustainable and decarbonized energy supply, "green" hydrogen is an emission-free alternative to conventional energy carriers. In this context, proton exchange membrane fuel cells (PEMFCs) offer promising properties for the electromobility by a simple scalability of the performance through the modular design of fuel cell stacks, a refueling time and range comparable with conventional combustion engines and zero emissions if "green" hydrogen is used. Despite all scientific work on this field – performance, cost and durability issues still hamper the wide commercialization of PEMFCs.Concerning the durability, global fuel starvation causes destructive and irreversible degradation at the anode catalyst. A lack of fuel supply leads to the anode potential being raised to levels where the oxygen evolution reaction (OER) and carbon oxidation reaction (COR) take place instead of the hydrogen oxidation reaction (HOR). Thus, the overall cell voltage reverses compared to normal operation. In consequence, the widely employed carbon-supported anode catalyst corrodes and the overall cell performance is reduced if appropriate mitigation strategies are absent [1]. Among other remedies, incorporating a second catalyst component with an enhanced OER activity, such as IrO2 [2], is a promising material-specific strategy. Within this study we present a technical approach on single cell level (50 cm2 geo) to investigate and evaluate the impact of short-pulsed versus long-lasting fuel starvation events on the degradation of a reversal-tolerant anode catalyst layer comprising Pt/C and IrO2 [3]. By utilizing an on-line mass spectrometer, the anode exhaust gas stream is examined in terms of O2- and CO2-amounts to reveal the origin of the degrading effect.

Monitoring Carbon Corrosion in Anode of a PEM Fuel Cells Under Fuel Starvation Using a Hydrogen Reference Electrode and on-Line Mass Spectrometry

Polymer electrolyte membrane fuel cells (PEMFCs) has attracted great attention in transportation and stationary applications with zero emissions and high efficiency compared to conventional combustion engines. However, various factors limit the lifespan of PEMFCs, which remain a major obstacle to large-scale commercialization. In particular, corrosion of the carbon support is one of the main causes of fatal and irreversible deterioration of PEMFCs performance.If the hydrogen fuel supply is insufficient to maintain current demand due to poor water management or fuel depletion at the anode, carbon corrosion may occur on the anode side. In this fuel starvation condition, reactions that take place in place of hydrogen oxidation, such as water electrolysis and oxidation of the carbon support, compensate for the current shortage.The exact deterioration mechanism of PEMFCs in fuel starvation is investigated by simultaneously monitoring the potential behavior from the anode and the exhaust gas using hydrogen reference electrodes and in situ online mass spectrometry. Interestingly, water electrolysis starts at a lower potential range and carbon oxidation occurs at a higher range as an alternative reaction to hydrogen oxidation. Thus, carbon corrosion, which is detrimental to cell performance, can be reduced by extending the duration of the water electrolysis reaction. In this regard, the introductions of the graphitized carbon support and water electrolysis catalyst to the anode are effective in alleviating damage due to fuel starvation by making a dominant alternative reaction to continue electrolysis of water. And this alternative reaction is Monitored with a hydrogen reference electrode and using on-site online mass spectrometry.