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The article titled "Design of a test bench for internal combustion engines for the School of Mechanical Engineering" presents the design of a test bench with a bench dynamometer and testing protocols for the School of Mechanical Engineering at the University of Costa Rica. The objective is to provide a tool that allows for cutting-edge studies on internal combustion engines and contribute to the development of alternative fuels and naturally sourced lubricants with a lower environmental impact. The design includes the construction plans for the test bench, as well as complementary systems such as the exhaust gas system, ventilation system, engine cooling system, and sound insulation. Although the design has not been completed, schematics are presented that describe the progress of the project to date. [Extracted from the article]

Scale-resolving simulations (SRS) are becoming more and more important for internal combustion (IC) engine simulations and are gradually replacing first-generation unsteady Reynolds-averaged Navier-Stokes (URANS) based approaches. In addition to the substantial improvement in the prediction of the local flow and mixing processes and their interaction with the spray and the turbulent flame, SRS are essential for the quantification of cycle-to-cycle variation (CCV) of coherent structures and sporadically occurring phenomena such as misfire and knock. However, the choice of a suitable scale-resolving turbulence model for specific applications such as IC engine flows is still an unresolved issue even in the scientific community. Typically, turbulence models are developed and validated for well-defined test cases and it is not clear whether these findings are also valid for flows in complex geometries with moving boundaries, where local flow structures might be significantly different. The flow in IC engines is characterized by strongly varying Reynolds numbers and exhibits several flow phenomena such as wall boundary layers, stagnation points, free-stream shear layers and edge-induced flow separations. The current paper is a systematic comparative study of selected and well-established scale-resolving turbulence models in the context of an IC engine flow focussing especially on the intake stroke. Different classical LES models (Smagorinsky, WALE, Sigma), a hybrid model (DES-SST) and a second-generation URANS model with scale-resolving capabilities (SAS-SST) are compared against each other. The models’ accuracy and capability to capture fluctuations, local flow structures and CCV during the tumble formation in the intake phase are investigated for a well-established IC engine benchmark case with a single non-moving valve. Though this is a simplified setup, it provides the unique possibility to compare the results to reference data obtained from experiment and direct numerical simulations (DNS). In a first step, the predicted averaged velocity and the resolved fluctuations obtained with the different models are compared to each other and to the reference data. Afterwards, the local structure of the resolved fluctuations is investigated in terms of an invariant analysis of the anisotropy tensor. Finally, the capability to resolve CCV is investigated based on the averaged and instantaneous tumble center, a large-scale flow structure specifically important for engine flows. [ABSTRACT FROM AUTHOR]

Computational methodology of large eddy simulation (LES) is tested in a real internal combustion engine geometry. Premixed turbulent combustion and the behavior of flame propagation are studied and compared with different LES and combustion process models. KIVA-3V, an open source Fortran code, is modified to implement large-eddy simulation technique based on one-equation sub-grid scale (SGS) turbulent kinetic energy and Smagorinsky models. For combustion process, improved turbulent-mixing combustion models based on eddy-dissipation model (EDM) and modified eddy-dissipation concept (EDC) are implemented and studied in case of using LES. The models with modified combustion processes of EDM and EDC are validated using experimental data of premixed combustion of laboratory burner with application of converging optimum and desired combustion model constants. Also experimental in-cylinder pressure data are used to validate the numerical CFD results of engine geometry. The physics of flow structure, flame propagation, heat energy released and fuel mass consumption during combustion are studied and compared by LES models. It is observed that large-scale of unsteady turbulent flow motions are developed before spark ignition that makes different behavior of flame front shape in combustion process with different turbulent models. Also numerical simulations indicate that different LES turbulence models may not capture the same flame propagation structure, whereas LES dynamic SGS viscosity models in comparison with standard constant models, almost capture the same flame front shape and propagation structure in the combustion chamber. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a procedure for studying dynamical behaviors of a simplified engine-propeller dynamical system consisting of a number of bodies of plane motions. The equation of motion of the complex system is obtained using the Lagrange equation and solved numerically using the 4th order Runge–Kutta method. Various simulations were performed to investigate the transient and steady state behaviors of the multiple body system while taking into consideration the engine pressure pulsations, nonlinear inertia of moving bodies, and nonlinear aerodynamic load. Sub-harmonics and super harmonics in the steady state responses for different power and propeller pitch settings are obtained using the fast Fourier transform. Numerical simulations indicate that the 1.5 order is the dominant order of harmonics in the steady state oscillatory motion of the crankshaft. The findings and procedure presented in the paper are useful to the aerospace industry in certifying reciprocating engines and propellers. The crankshaft oscillatory velocities obtained from the simplified rigid body model are in good agreement with the experimental data for a SAITO-450 engine and a SOLO propeller at a 6″ pitch setting. [Copyright &y& Elsevier]

The article discusses the study of Matthew McNenly, engineer at Lawrence Livermore National Laboratory, using an innovative computational method that leverages modeling of chemical systems behavior for internal combustion engine. Topics include the interaction of chemical components within conventional hydrocarbon fuels, the complex chemical reaction networks, and the use of matrix preconditioners to develop sparse approximations to the reaction network.

General Motors (GM) plans to transition its entire light-duty vehicle fleet to electric vehicles (EVs) by 2035, bringing an end to its production of gasoline- and diesel-powered vehicles. The automaker aims to go carbon neutral by 2040. [ABSTRACT FROM AUTHOR]

The British government has brought forward a ban on the sale of internal combustion engine cars in a move which will boost demand for battery materials, including lithium. [ABSTRACT FROM AUTHOR]