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The race towards zero carbon emissions is ongoing with the need to reduce the consumption of fossil energy resources. This demands immediate and reliable developments regarding technical environmentally friendly solutions for the power and transportation sectors. An alternative way to achieve a carbon-free powertrain is the use of green hydrogen for internal combustion engines. Operating a hydrogen-fuelled engine offers many opportunities as well as challenges that need to be addressed. In this work the self-designed Fraunhofer single cylinder engine with a displacement volume of 500 cm³ derived for extreme lean combustion and passive pre-chamber ignition was adapted for hydrogen engine operation. With hydrogen combustion, the customized cooling system resulting in low metal temperatures is simulated and optimized to avoid hot spots in the combustion chamber.

The use of hydrogen as an alternative fuel to power cogeneration gas engines has been a research topic over the last few decades and has currently gained importance, even more due to current circumstances related to decarbonisation efforts for the energy supply. A significant part of the research done is focused on the topic of combustion diagnostics, which can be fulfilled through different methods. This work investigates the feasibility of the ion current sensing for a pure hydrogen fueled series natural gas cogeneration engine. For this purpose, a variation of the fuel composition (100% natural gas to 100% hydrogen) was carried out while maintaining the indicated mean effective pressure (IMEP) and the combustion phasing (CA50). This demonstrated that the efficiency increased monotonically as the hydrogen concentration rose. Simultaneously, the ion current signal gradually dropped but was still detectable at 100% hydrogen combustion.

Author and Co-authors: M.Sc. Aristidis Dafis (IMS), Prof. Dr.-Ing. Hermann Rottengruber (IMS), Dr.-Ing. Paul Jochmann (Robert Bosch GmbH), Dr.-Ing. Erik Schünemann (Robert Bosch GmbH) Abstract: In the context of the energy transition, CO2-neutral solutions are of enormous importance for all sectors, but especially for the mobility sector. Hydrogen as an energy carrier has therefore been the focus of research and development for some time. However, the development of hydrogen combustion engines is in many respects still in the conception phase. Automotive system providers and engineering companies in the field of software development and simulation are showing great interest in the topic. In a joint project with the industrial partners Robert Bosch GmbH and AVL Germany, combustion in a H2-DI-engine for use in light-duty vehicles was methodically investigated using the CFD tool AVL FIRE®.

SI engines fueled with hydrogen represent a promising powertrain solution to meet the ambitious target of carbon-free emissions at the tailpipe. Therefore, fast and reliable numerical tools can significantly support the automotive industry in the optimization of such technology. In this work, a 1D-3D methodology is presented to simulate in detail the combustion process with minimal computational effort. First, a 1D analysis of the complete engine cycle is carried out on the user-defined powertrain configuration. The purpose is to achieve reliable boundary conditions for the combustion chamber, based on realistic engine parameters. Then, a 3D simulation of the power-cycle is performed to mimic the combustion process. The flow velocity and turbulence distributions are initialized without the need of simulating the gas exchange process, according to a validated technique.

Cogeneration represents a key element within the energy transition by enabling a balancing of the long-term fluctuations of regeneratives. Regarding the expected increase of hydrogen share in natural gas pipelines in Germany, this work deals with investigations of hydrogen-associated advantages for the lean and stoichiometric operations of natural gas cogeneration engines, in relation to numerous challenges, such as the efficiency-NOx trade-off. Charge dilution is commonly regarded as one of the most effective ways for improving thermal efficiency of spark-ignition gas engines. While excess air serves as a diluent in the lean combustion process, stoichiometric combustion dilution may be obtained by exhaust gas recirculation (EGR). Combining hydrogen addition with mixture dilution is an appealing approach for a better handling of the efficiency-emissions trade-off.

Given its ability to be combined with the three-way catalyst, the stoichiometric operation is significantly more attractive than the lean-burn process, when considering the increasingly severe NOx limit for cogeneration gas engines. However, the high temperature of the stoichiometric combustion results in increased wall heat losses, restricted combustion phasings (owing to knock tendency) and thus efficiency penalties. To lower the temperature of the stoichiometric combustion and thus improve the engine efficiency, exhaust gas recirculation (EGR) is one of the most effective means. Nevertheless, the dilution with EGR has much lower tolerance level than with excess air, which leads to a consequent drop in the thermal efficiency. In this regard, reducing the water vapor concentration in the recirculated exhaust gas and increasing the EGR reactivity are two potential measures that may extend the mixture dilution limit and result in engine efficiency benefits.

In the course of the Horizon 2020 project ICE GENESIS of the European Union, an experimental database was developed to host documentation of icing experiments. The database serves as a source of information for numerical code development and validation as well as future test matrix design, IPS layout and development and wing design. Several legacy data icing cases have been included into the database, which are partly publicly available. Furthermore, the database will serve as the main platform for dissemination of public results of icing cases after and during the project ICE GENESIS. The database itself provides detailed information about the test configurations and the icing wind tunnel operator. More specifically, CAD data, ice protection system characteristics if applicable, installation in the test facility, instrumentation, test matrix, generated aero-icing conditions and test results.

The National Research Council Altitude Icing Wind Tunnel liquid water content calibrations have historically relied on a 2.4 mm diameter rotating cylinder for droplet sizes up to 50 µm and a 6.2 mm diameter rotating cylinder for droplet sizes up to 200 µm. This study compares the AIWT calibration, extrapolated from rotating cylinder measurements, to water content measurements from the Science Engineer Associates Multi-Element Probe and the NRC Compact Iso-Kinetic Probe over a range of airspeeds and droplet sizes. The goals of this work are to characterize the different measurement instrument responses under small droplet conditions where there is good confidence in the AIWT rotating cylinder-based calibration, as well as to better understand the limitations of the rotating cylinder measurements at large droplet sizes where there may be splashing and droplet re-entrainment into the flow.

The in-flight ice accretion simulations are typically performed using a multi-step approach. As the ice grows, the geometry changes, and an adaptation of the fluid volume used by the airflow and droplet-trajectory solver is required. Re-meshing or mesh deformation are generally employed to do that. Consequently, difficulties are encountered when trying to automate the process. Contrary to the usual body-fitted mesh approach, the use of immersed boundary methods (IBMs) allows solving, or greatly reducing, this problem by removing the mesh update, facilitating the global automation of the simulation. In the following paper, a new approach to perform the airflow and droplet trajectory calculations for three-dimensional simulations is presented. This framework utilizes only immersed boundary methods. In particular, two methods are presented. On the one hand, a ghost-cell method has been developed to solve the Euler flow.

The usage of forging a preformed, near net shape, compacted and sintered metal powder has been widely accepted since the eighties and is now one of the mainstays for producing Connecting rods in North America. However, its use in Indian subcontinent is limited as its counterpart i.e. conventional steel forging is still the most dominant. Powder metallurgy route has many advantages like good dimensional accuracy; minimum scattering of weight etc. Despite these advantages, the Powder metallurgy process is still not preferred predominantly due to technical (endurance) and infrastructural limitations. This work envisages combining the benefits of powder metallurgy process with the required mechanical properties viz. tensile and fatigue strength alongside design modifications to meet the requirements of a connecting rod for a 2-cylinder diesel engine. The connecting rods met the fatigue life at the required FOS equaling the performance of a conventionally forged connecting rod.

The oil is picked up from the oil sump and transferred to the pump housing via a suction tube at the desired rate. A strainer is fitted to the end of the suction tube to filter out any dust or debris that may be present. Steel tubes and wire mesh strainers are used to make the current suction tube. Suction tube design shouldn't have an excessively long inlet suction that would make the suction tube's pressure insufficient to suck the oil from sump. Additionally, the pump's suction side air leak or low temperature-induced low oil viscosity prevents the pump from priming. This paper will examine suction tube design analysis and compared the development of steel and polymer suction tube concepts. The lightweight polymer suction tube with respect to fluid dynamics aspects is compared with conventional wire mesh.

Over the last decade, Climate change due to fossil fuel burning has taken centre stage in all discussions. Automotive sector has come under some flak for being one of the contributors to this Climate Change. Active steps have been taken by Vehicle Manufacturers and their Suppliers to address this issue. This sector has been facing below challenges to reduce pollutant in the air by A. Reducing Emissions, B. Increasing Energy Efficiency C. Use of Renewable Energy. One of the many alternatives by the Automotive Industry was to have a phased introduction to Electric Vehicles (EV), Hybrids, Fuel cells and other variants. As various emission norms and safety requirements takes Centre stage, it invariably, increases the weight of the vehicle. Now a days, Vehicles are having challenges to make it lightweight to achieve Range for an EV and improve fuel efficiency without sacrificing safety.

The automotive industry is facing a challenge as efficiency improvements are required to address the strict emission norms which in turn requires high performance downsized, lightweight IC engines. The increasing demand for lightweight engine needs high strength to weight ratio materials. To meet high strength to weight ratio, castings are preferable. However due to strength limitations for critical crankshaft applications, it forces to use costly forgings such as micro alloyed forging steel and Martensitic (after heat treatment) forging steel. To reduce the cost impact, high strength Austempered Ductile iron (ADI) casting is developed for crankshaft applications to substitute steel forgings. Austempered Ductile Iron is having an excellent mechanical properties due to aus-ferritic structure. The improved properties of developed ADI Crankshaft over steel forged crankshaft offers additional weight advantage.

With the introduction of CAFÉ norms (Corporate Average Fuel Economy or Efficiency) in automobile industries, gasoline engines must improve their fuel economy by reducing overall CO2 footprints. To fulfil this demand many OEMs have adopted the use of exhaust gas circulation coolers (EGR) Most of the gasoline engines are having exhaust gas temperatures ranging from 650-850°C, these gases could also be highly corrosive in nature. It’s very important to select the right grade of stainless steel which should have high corrosion resistance and oxidation properties. It should also withstand high temperatures and should have low sensitization at high temperatures. Most of grades stainless steel offers high resistance against corrosion, high temperature properties. But good sensitization at high temperature is not always associated with all grades of steel. To compare corrosion resistivity, PREN number (Pitting Resistance Equivalent Number) plays important role.

Due to the emerging technologies and globalization, expectations of the customers on commercial vehicles are getting increased over the period. It is an important duty of an OEM to deliver a perfectly configured product to suit the customer requirements. When it comes to configuration of a vehicle, engine power is one of the key factors which indicate the performance of that vehicle. There is a tough competition between every OEM to increase the engine power for enhancing the overall operational performance. One method to increase power is to improve its volumetric efficiency. This is achieved with help of turbocharger and Charge Air Cooler (CAC). CAC improves volumetric efficiency by increasing intake air-charge density. Any failure on CAC leads to lower the volumetric efficiency and increase in turbocharger loading. This paper deals with the validation of CAC assembly using different test conditions by analyzing potential failure modes against the field issues.

The design and development of a hydrogen powered spark-ignition engine, aimed for installation on a vehicle for on-road application. The experiment was conducted at WOT (Wide Open Throttle) condition at a speed of 4000 rpm with an excess air-fuel ratio of 1.3, 1.5, 2.2, 2.5, 3, 3.75, and 4.0. The ignition timing was optimized for maximum torque at each value of the excess air ratio. The various parameters analyzed such as in-cylinder pressure, Pressure and Volume, Logarithm of Pressure and Volume, Mass fraction burned, Cummulative heat release, Net heat release, Rate of pressure rise, and Mean gas temperature. The results show that there is a profound effect of excess air-fuel ratio on the engine’s mean effective pressure, output power, Brake thermal efficiency, Volumetric efficiency, Brake specific fuel consumption, and NOx emissions. The peak cylinder pressure decreases with an increase in excess air-fuel ratio and NOx emissions are reduced due to reduced mean gas temperature.

Interdiffusion analysis in multicomponent alloy systems plays a pivotal role in controlling various processes and in designing materials. Interdiffusion of elements also leads to changes in microstructure and properties during service, especially for the materials operating at elevated temperatures. The urge of increasing efficiency of gas turbine engines has led to the demand of higher service temperatures and longer life, which is achieved by the application of thermal barrier coatings (TBC) on Ni based superalloys. To prevent oxidation damage to the superalloy substrate, bond coats are used in which diffusion acts as a key factor influencing the stability and durability of the engine components. Over the last few decades, β-(Ni,Pt)Al coatings have been widely employed as bond coat materials because the presence of Pt enhances oxidation resistance by accelerating diffusion of Al to generate a continuously growing TGO (Thermally grown oxide) layer.

The prediction of accurate evaporation rates for aviation fuels, which are complex mixtures of hundreds of hydrocarbon components with varying evaporation characteristics, remains a challenge. Multi-component vaporization models, such as distillation curve (DC) and diffusion limit (DL), are capable of predicting evaporation rates well but require the construction of surrogate fuels, which is difficult. Mono-component models, on the other hand, can be used for rapid evaporation conditions similar to those in a heat engine combustion chamber, with acceptable uncertainties. However, the accuracy of these models under engine-relevant operating conditions is unclear. This study aims to address this research gap by experimentally measuring the evaporation rates of two aviation fuels (TS-1 and Jet-A1) at different temperature conditions and evaluating the feasibility of current theoretical models for predicting evaporation rates under engine-relevant conditions.

This paper describes lightning fuel ignition source test data on cracked aluminum and hydraulic tubes. The tube test articles included several different types of cracks and establish ignition source threshold current densities that exceed what is expected in traditional aluminum fuel tanks for midsize business jets, which notably are higher than typical current densities in larger Part 25 airplanes. Additionally, the fuel tube test data compared to ignition source current thresholds associated with tube couplers and fittings show consideration of cracks in the tubing will not typically be a critical factor in showing compliance or determining design constraints.

This paper describes a simulation methodology developed for gear rattle severity evaluation and drivetrain architecture optimization. The noise generated by gear rattle is one of the main contributors towards customer’s overall NVH perception. This study adopts a model-based design approach to simulate the tendency of gear rattle in neutral and drive conditions. Gear rattle simulation model for Tractor driveline developed in 1-D environment and correlated with test data acquired on tractor drivelines for multiple field applications. This analytical physics-based model includes engine torsional signature, clutch damper torsional characteristic and dynamics of traction and PTO driveline. This dynamic simulation model helps to understand and predict the gear rattle severity of various drivetrain architecture early in the product development cycle and assess & Optimize driveline NVH performance.