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Technical Paper

Study of Structural Noise of a Multi-Cylinder Diesel Engine

2024-09-19
2024-28-0074
The world over has resulted in severe pollution problems.They are classified as air and noise pollution.Air pollution is caused by to dispersion of emittents from engine exhaust to the atmosphere at different concentration levels. Similarly,the emission of unwanted sound from engine structure, intake and exhaust is the principal source of noise pollution.
Technical Paper

Dual Injection Concept and Lean Burn Characteristics with Methanol on a SI-Engine

2024-09-18
2024-24-0030
To further unlock the potential of methanol, this paper focuses on a dual injection concept in a spark ignition (SI) combustion engine. The combination of port fuel injection (PFI) and direct injection (DI) for different fuel types, as well as single and dual fuel applications, such as gasoline for PFI and methanol for DI, has been discussed in the literature. The consideration of a single-fuel dual injection concept with pure methanol is intended to provide information on the characteristics of each injection method and, by combining these, eliminate the disadvantages of one type with the advantages of the other. The research for sustainable alternative fuels for combustion engines was driven by the urgency to meet future emission regulation norms and mitigate climate change and dependency on fossil fuels.
Technical Paper

Optimization of a virtual H2 engine using a 1D simulation tool targeting high engine performance along with near-zero emission levels.

2024-09-18
2024-24-0015
Hydrogen engines are currently considered as a viable solution to preserve the internal combustion engine (ICE) as a power unit for vehicle propulsion. In particular, lean-burn gasoline Spark-Ignition (SI) engines have been a major subject of investigation, due to their reduced emission levels and high thermodynamic efficiency. Lean charge is suitable for passenger car applications, where the demand of mid/low power output does not require an excessive amount of air to be delivered by the turbocharging unit, but can difficulty be tailored in the field of high-performance engine, where the air mass delivered would require oversized turbocharging systems or more complex charging solutions. For this reason, the range of feeding conditions near the stochiometric is explored in the field of high-performance engines, leading to the consequent issue of abatement of pollutant emissions.
Technical Paper

A homogenization-based technique for a simplified numerical Finite Element approach to describe the structural behaviour of cylindrical cells battery pack

2024-09-18
2024-24-0021
The continuously increasing demand for Battery Electric Vehicle, together with the customer requirement for higher ranges poses new challenges on the battery pack design. Drawing inspiration from aerospace design principles, wherein fuel tanks are integrated structurally into airframes to save weight and increase efficiency, similar approaches exist for battery packs. When a structural battery pack is considered, significant weight savings can be achieved, potentially extending the vehicle range. Additionally, this weight saving could be further exploited to increase the battery pack size without adding extra weight with respect to a non-structural battery pack, further enhancing the vehicle range. Finite Element simulations are typically adopted to assess the integrity of a battery pack and estimate its contribution to the structural behaviour of the overall vehicle.
Journal Article

Cavitation Phenomenon and Spray Atomization in Different Types of Diesel Engine Nozzles: A Systematic Review

2024-07-13
Abstract The high-pressure common rail fuel injection system for diesel engines is one of the core technologies that need to be addressed in the automobile industry. The control of the internal flow in multi-hole injector nozzles is the key to achieve accurate control of the fuel injection and spray process. There are various types of research on cavitation phenomena currently conducted on various types of test benches, but there is no conclusive discussion. Therefore, it is to summarize these studies in order to identify the highlights of existing studies and point out their shortcomings. This article compares and analyzes the developing patterns of cavitation phenomena on four test benches through literature review and has obtained rich research data on these four types of nozzles, but they still have their own shortcomings at the same time, even with numerical simulation.
Technical Paper

Harmonic Injection Method for NVH Optimization of Permanent Magnet Synchronous Motors Considering the Structural Characteristics of the Machine

2024-07-02
2024-01-3015
Noise, vibration and harshness (NVH) is one of the most important performance evaluation aspects of electric motors. Among the different causes of the NVH issues of electrical drives, the spatial and temporal harmonics of the electrical drive system are of great importance. To reduce the tonal noise of the electric motors induced by these harmonics, harmonic injection methods are applied in many applications. However, a lot of existing researches focus more either on improving the optimization process of the harmonic injection parameter settings, or on the controller design of the harmonic injection process, while the structural dynamic characteristics of the motor are seldom considered.
Technical Paper

A Computational Study of Hydrogen Direct Injection Using a Pre-Chamber in an Opposed-Piston Engine

2024-07-02
2024-01-3010
Combustion characteristics of a hydrogen (H2) direct-injected (DI) pre-chamber (PC)-assisted opposed piston two-stroke (OP2S) engine are investigated by 3D computational fluid dynamics (CFD) simulations. The architecture of the OP2S engine has potential features for reducing wall heat losses, as the DI H2 jets are not directed towards the piston face. To overcome the high resistance to autoignition of H2, a PC technology was implemented in order to enhance the ignition of the mixture by the multiple hot reactive jets. To further investigate the interaction between the H2 plume and the chamber walls, three different piston bowl designs were evaluated and ranked based on a merit function. For the cases under study, the flat piston design was found to be most favorable (compared to the narrow and wide pistons) due to its reduced surface area for lower wall heat losses.
Technical Paper

Numerical Investigation of Injection and Mixture Formation in Hydrogen Combustion Engines by Means of Different 3D-CFD Simulation Approaches

2024-07-02
2024-01-3007
For the purpose of achieving carbon-neutrality in the mobility sector by 2050, hydrogen can play a crucial role as an alternative energy carrier, not only for direct usage in fuel cell-powered vehicles, but also for fueling internal combustion engines. This paper focuses on the numerical investigation of high-pressure hydrogen injection and the mixture formation inside a high-tumble engine with a conventional liquid fuel injector for passenger cars. Since the traditional 3D-CFD approach of simulating the inner flow of an injector requires a very high spatial and temporal resolution, the enormous computational effort, especially for full engine simulations, is a big challenge for an effective virtual development of modern engines. An alternative and more pragmatic lagrangian 3D-CFD approach offers opportunities for a significant reduction in computational effort without sacrificing reliability.
Technical Paper

Experimental and Numerical Investigations of a Dual-Fuel Hydrogen–Kerosene Engine for Sustainable General Aviation

2024-06-17
2024-01-6001
Reducing CO2 emissions is an increasingly important issue. In aviation, approaches such as e-propulsion only represent a solution for special applications due to the low energy density of batteries. Because of the low-cost and robust design of combustion engines, this concept is still the most suitable for general aviation. For defossilization, besides e-fuels and bio-fuels, which represent the so-called sustainable aviation fuels (SAF), hydrogen can serve as a promising energy carrier for CO2 reduction. For this purpose, the combustion process of a dual-fuel hydrogen–kerosene (Jet A-1) engine was developed and investigated for use in small aircrafts. This study explores the influence of hydrogen addition on combustion parameters, emissions, and efficiency.
Journal Article

Engine Behavior Analysis on a Conventional Diesel Engine Powered with Blends of Lemon Grass Oil Biodiesel–Diesel Blends

2024-06-14
Abstract Fossil fuel usage causes environmental pollution, and fuel depletion, further affecting a country’s economy. Biofuels and diesel-blended fuels are practical alternatives to sustain fossil fuels. This experimental study analyses lemongrass oil’s performance, emissions, and combustion characteristics after blending with diesel. Lemongrass oil is mixed with diesel at 10 (B10), 15 (B15), and 25% (B25) and evaluated using a 5.20 kW direct injection diesel engine. B10 brake thermal efficiency is 36.47%, which is higher than other blends. The B10 displays an 8.73% decrease in brake-specific fuel consumption compared to diesel. An increase in exhaust gas temperature for B10 than diesel is 4.5%. It indicates that higher lemongrass oil blends decrease exhaust gas temperature. The decrease in average carbon monoxide emissions in B10 to diesel is 22.19%. The decrease in hydrocarbon emissions for B10 to diesel is 7.14%.
Technical Paper

Acoustic Quality Assurance during End of Line Engine Test Approval

2024-06-12
2024-01-2922
Liebherr Machines Bulle SA (LMB) designs and produces High-quality diesel engines, injection systems as well as hydraulic components. Liebherr has an Acoustic End of Line (AEOL) system on serial test benches. All engines are measured, and noises are evaluated by operators. This subjective evaluation leads to dispersion on the evaluations, particularly for whining noise. To ensure customer satisfaction, Liebherr wishes to define a new methodology to find a quantitative and objective criterion to set a robust engine noise compliance standard. This new methodology is based on near field microphone measurement of an engine run-down. First, whining noise signatures are extracted from the raw signal. Secondly, psychoacoustic indicators are calculated on the extracted signatures. Thresholds are then established to validate engine deliveries. Finally, this process combining advanced signal processing and psychoacoustics is automated using the Ansys Sound Python library in mass production.
Technical Paper

The Potential of Hydrogen High Pressure Direct Injection toward Future Emissions Compliance: Optimizing Engine-Out NOx and Thermal Efficiency

2024-06-12
2024-37-0005
By building on mature internal combustion engine (ICE) hardware combined with dedicated hydrogen (H2) technology, the H2-ICE has excellent potential to accelerate CO2 reduction. H2-ICE concepts can therefore contribute to realizing the climate targets in an acceptable timeframe. In the landscape of H2-ICE concepts, pilot-ignited High Pressure Direct Injection (HPDI™) is an attractive option considering its high thermal efficiency, wide load range and its applicability to on-road as well as off-road heavy-duty equipment. Still, H2-HPDI is characterized by diffusion combustion, giving rise to significant NOx emissions. In this paper, the potential of H2-HPDI toward compliance with future emissions legislation is explored on a 1.8L single-cylinder research engine. With tests on multiple load-speed points, Exhaust Gas Recirculation (EGR) was shown to be an effective measure for reducing engine-out NOx, although at the cost of a few efficiency points.
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