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In recent years, improvements in the fuel economy and exhaust emission performance of internal combustion engines have been increasingly required by regulatory agencies. One of the salient concerns regarding general purpose engines is the larger amount of CO emissions with which they are associated, compared with CO emissions from automobile engines. To reduce CO and other exhaust emissions while maintaining high fuel efficiency, the optimization of total engine system, including various design parameters, is essential. In the engine system optimization process, cycle simulation using 0-D and 1-D engine models are highly useful. To define an optimum design, the model used for the cycle simulation must be capable of predicting the effects of various parameters on the engine performance. In this study, a model for predicting the performance of a general purpose SI (Spark Ignited) engine is developed based on the commercially available engine simulation software, GT-POWER.

Using a holistic 1D engine simulation approach for the modelling of full-transient engine operation, allows analyzing future engine concepts, including its exhaust gas aftertreatment technology, early in the development process. Thus, this approach enables the investigation of both important fields - the thermodynamic engine process and the aftertreatment system, together with their interaction in a single simulation environment. Regarding the aftertreatment system, the kinetic reaction behavior of state-of-the-art and advanced components, such as Diesel Oxidation Catalysts (DOC) or Selective Catalytic Reduction Soot Filters (SCRF), is being modelled. Furthermore, the authors present the use of the 1D engine and exhaust gas aftertreatment model on use cases of variable valve train (VVT) applications on passenger car (PC) diesel engines.

Renewable fuels, such as bio- and e-fuels, are of great interest for the defossilization of the transport sector. Among these fuels, methanol represents a promising candidate for emission reduction and efficiency increase due to its very high knock resistance and its production pathway as e-fuel. In general, reliable simulation tools are mandatory for evaluating a specific fuel potential and optimizing combustion systems. In this work, a previously presented methodology (Esposito et al., Energies, 2020) has been refined and applied to a different engine and different fuels. Experimental data measured with a single cylinder engine (SCE) are used to validate RANS 3D-CFD simulations of gaseous engine-out emissions. The RANS 3D-CFD model has been used for operation with a toluene reference fuel (TRF) gasoline surrogate and methanol. Varying operating conditions with exhaust gas recirculation (EGR) and air dilution are considered for the two fuels.

Crankshafts of motorcycles require high strength, high reliability and low manufacturing cost. Recently, a reduction of Pb content in the free-cutting steel, which is harmful substance, is required. In order to satisfy such requirements, we started the development of Pb-free free-cutting steel which simultaneously enabled the omission of the normalizing process. For the omission of normalizing process, we adjusted the content of Carbon, Manganese and Nitrogen of the steel. This developed steel can obtain adequate hardness and fine microstructure by air-cooling after forging. Pb-free free-cutting steel was developed based on Calcium-sulfur free-cutting steel. Pb free-cutting steel is excellent in cutting chips frangibility in lathe process. We thought that it was necessary that cutting chips frangibility of developed steel was equal to Pb free-cutting steel. It was found that cutting chips frangibility depend on a non-metallic inclusion's composition, shape and dispersion.

There is a movement to apply emission control in a marine engine as well due to high public awareness of environmental concern in the United States. We started at the development of 3-seater Personal Watercraft (PWC) equipped with 4-stroke engines in taking environment conformity and potential into account. The PWC employed series 4-cylinder 1100cc displacement engine that has been used for mass production motorcycles. The engine was modified to satisfy requirements for PWC, as a marine engine, such as performance function and corrosion. In order to achieve greater or equal power/weight ratio as against two-stroke PWCs, a four-stroke engine for PWC with an exhaust turbo charger was developed. As a result, we succeeded in developing an engine that attained top-level running performance and durability superior to competitors' 2-stroke engines.

A numerical calculation method, which enables the analysis of gear train behavior including non-linear elements in a motorcycle engine, was established. During the modeling process, it was confirmed that factors such as bearing distortion, radial bearing clearance and elastic deformation of a tooth flank could not be neglected because they effect the rotation behavior. To keep a high accuracy, those factors were included in the simulation model, after they were converted into the rigidity elements along the rotational direction of each gear model. In addition, the model was combined with a crankshaft behavior calculation model for a driving and excitation source. A time domain numerical integration method was used to perform the transient response simulation across a wide range of engine speeds. A jump phenomenon of response behavior of the driven gear was predicted that is a characteristic of non-linear response. The phenomenon was also observed in a physical test.

Modeling plume interaction and collapse for direct-injection gasoline sprays is important because of its impact on fuel-air mixing and engine performance. Nevertheless, the aerodynamic interaction between plumes and the complicated two-phase coupling of the evaporating spray has shown to be notoriously difficult to predict. With the availability of high-speed (100 kHz) Particle Image Velocimetry (PIV) experimental data, we compare velocity field predictions between plumes to observe the full temporal evolution leading up to plume merging and complete spray collapse. The target “Spray G” operating conditions of the Engine Combustion Network (ECN) is the focus of the work, including parametric variations in ambient gas temperature. We apply both LES and RANS spray models in different CFD platforms, outlining features of the spray that are most critical to model in order to predict the correct aerodynamics and fuel-air mixing.

Subject of this work is a simulation model for PCCI combustion that can be used in closed-loop control development. A detailed multi-zone chemistry model for the high-pressure part of the engine cycle is extended by a mean value model accounting for the gas exchange losses. The resulting model is capable of describing PCCI combustion with stationary excactness. It is at the same time very economic with respect to computational costs. The model is further extended by identified system dynamics influencing the stationary inputs. For this, a Wiener model is set up that uses the stationary model as a nonlinear system representation. In this way, a dynamic nonlinear model for the representation of the controlled plant Diesel engine is created.

The European Commission is going to publish the new Euro7 standard shortly, with the target of reducing the impact on pollutant emissions due to transportation systems. Besides forcing internal combustion engines to operate cleaner in a wider range of operating conditions, the incoming regulation will point out the role of On-Board Monitoring (OBM) as a key enabler to ensure limited emissions over the whole vehicle lifetime, necessarily taking into account the natural aging of involved systems and possible electronic/mechanical faults and malfunctions. In this scenario, this work aims to study the potential of data-driven approaches in detecting emission-relevant engine faults, supporting standard On-Board Diagnostics (OBD) in pinpointing faulty components, which is part of the main challenges introduced by Euro7 OBM requirements.

This paper introduces a new type of aluminum radiator that has been developed with the objective of high performance and light weight. Aluminum radiators have recently been replacing copper radiators because of their light weight, but the heat rejection of such conventional alminum radiators does not exceed that of copper radiators. Authors established the aluminum radiator not only being light weight but also having high performance through the following approaches. (1) Optimization of radiator core module. (2) Thickness reduction of tube and fin. (3) Development of aluminum alloys with improved corrosion resistance for tubes and fins. As a result, a new type single-row aluminum radiator has achieved 7% higher rejection at 50% lighter weight than those of copper double-row radiator.

A variable valving system was developed. This system has two cam profiles, one for low speed and one for high speed. A 1.2-litre DOHC experimental engine using this system was made and mounted in the body of a 2-1itre class passenger car. Test results of this car were compared to those of the same car with its original engine. The test car showed better results in every area of driving performance, in mode-fuel-econorny and in noise tests. This paper presents the mechanism, operation and test results of this variable valving system, the 1.2-litre experimental engine and this passenger car. THE PERFORMANCE AND EFFICIENCY of the passenger car gasoline engine have been greatly improved: primarily as a response to exhaust-gas emission regulations and the oil crises. These improvements have been achieved mainly through the development of control technologies to optimize many parameters such as ignition timing and air fuel ratio precisely according to driving conditions.

Striving for sustainable transportation solutions, hydrogen is often identified as a promising energy carrier and internal combustion engines are seen as a cost effective consumer of hydrogen to facilitate the development of a large-scale hydrogen infrastructure. Driven by efficiency and emissions targets defined by the U.S. Department of Energy, a research team at Argonne National Laboratory has worked on optimizing a spark-ignited direct injection engine for hydrogen. Using direct injection improves volumetric efficiency and provides the opportunity to properly stratify the fuel-air mixture in-cylinder. Collaborative 3D-CFD and experimental efforts have focused on optimizing the mixture stratification and have demonstrated the potential for high engine efficiency with low NOx emissions. Performance of the hydrogen engine is evaluated in this paper over a speed range from 1000 to 3000 RPM and a load range from 1.7 to 14.3 bar BMEP.

The present work discusses the potential benefits of using computational fluid dynamics (CFD) simulation and artificial intelligence (AI) in the design and optimization of hydrogen internal combustion engines (H2ICEs). A Machine Learning (ML) model is developed and applied to the CFD simulation data to identify optimal injection system parameters on the Sandia H2ICE Engine to improve the mixing. This approach can aid in developing predictive ML models to guide the design of future H2ICEs. For the current engine configuration, it is observed that hydrogen (H2) gas injection contributes mixing of H2 with air. If the injector parameters are optimized, mixture preparation is better and eventually combustion. A base CFD model is validated from the Sandia H2ICE engine data against Particle Image Velocimetry (PIV) data for velocity and Planar Laser Induced Fluorescence (PLIF) data for H2 mass fraction.

Simultaneous reduction of engine pollutants (e.g., CO, THC, NOx, and soot) is one of the main challenges in the development of new combustion systems. Low-temperature combustion (LTC) concepts in compression ignition (CI) engines like premixed charged compression ignition (PCCI) make use of pre-injections to create a partly homogenous mixture. In the PCCI combustion regime, a direct correlation between injection and pollutant formation is no longer present because of long ignition delay times. In LTC combustion systems, the in-cylinder pressure sensor is normally used to help the combustion control. However, to allow the control of PCCI engines, new sensor concepts are investigated to obtain additional information about the PCCI combustion for advanced controller structures. In LTC combustion systems like gasoline-controlled autoignition (GCAI) concepts, the application of ion current sensors enables additional monitoring of the combustion process with real-time capability.

Traditional Lagrangian spray modeling approaches for internal combustion engines are highly grid-dependent due to insufficient resolution in the near nozzle region. This is primarily because of inherent restrictions of volume fraction with the Lagrangian assumption together with high computational costs associated with small grid sizes. A state-of-the-art grid-convergent spray modeling approach was recently developed and implemented by Senecal et al., (ASME-ICEF2012-92043) in the CONVERGE software. The key features of the methodology include Adaptive Mesh Refinement (AMR), advanced liquid-gas momentum coupling, and improved distribution of the liquid phase, which enables use of cell sizes smaller than the nozzle diameter. This modeling approach was rigorously validated against non-evaporating, evaporating, and reacting data from the literature.

Road vehicles can expend a significant amount of energy in undesirable vertical motions that are induced by road bumps, and much of that is dissipated in conventional shock absorbers as they dampen the vertical motions. Presented in this paper are some of the results of a study aimed at determining the effectiveness of efficiently transforming that energy into electrical power by using optimally designed regenerative electromagnetic shock absorbers. In turn, the electrical power can be used to recharge batteries or other efficient energy storage devices (e.g., flywheels) rather than be dissipated. The results of the study are encouraging - they suggest that a significant amount of the vertical motion energy can be recovered and stored.

The 4th Workshop of the Engine Combustion Network (ECN) was held September 5-6, 2015 in Kyoto, Japan. This manuscript presents a summary of the progress in experiments and modeling among ECN contributors leading to a better understanding of soot formation under the ECN “Spray A” configuration and some parametric variants. Relevant published and unpublished work from prior ECN workshops is reviewed. Experiments measuring soot particle size and morphology, soot volume fraction (fv), and transient soot mass have been conducted at various international institutions providing target data for improvements to computational models. Multiple modeling contributions using both the Reynolds Averaged Navier-Stokes (RANS) Equations approach and the Large-Eddy Simulation (LES) approach have been submitted. Among these, various chemical mechanisms, soot models, and turbulence-chemistry interaction (TCI) methodologies have been considered.

Early activation of catalyst by quickly raising the temperature of the catalyst is effective in reducing exhaust gas during cold starts. One such technique of early activation of the catalyst by raising the exhaust temperature through substantial retardation of the ignition timing is well known. The present research focuses on the realization of quick warm-up of the catalyst by using a method in which the engine is fed with a large volume of air by feedforward control and the engine speed is controlled by retarding the ignition timing. In addition, an intake air flow control method that comprises a flow rate correction using an adaptive sliding mode controller and learning of flow rate correction coefficient has been devised to prevent control degradation because of variation in the flow rate or aging of the air device. The paper describes the methods and techniques involed in the implementation of a quick warm-up system with improved adaptability.

A reduced kinetic reaction mechanism for the autoignition of dimethyl ether is presented in this paper. Dimethyl ether has proven to be one of the most attractive alternatives to traditional fossil fuels for compression ignition engines. It can either be produced from biomass or from fossil oil. For dimethyl ether, Fischer et al. (Int. J.Chem. Kinet. 32 ( 12 ) (2000) 713-740) proposed a detailed reaction mechanism consisting of 79 species and 351 elementary reactions. In the present work, this detailed mechanism is systematically reduced to 31 species and 49 reactions. The reduced mechanism is discussed in detail with special emphasis on the high temperature thermal decomposition of dimethyl ether and on the fuel specific depleting reactions, which produce the methoxymethyl radical. In addition, a reaction pathway analysis for low temperature combustion is applied, where hydroperoxy-methylformate is found to be the dominating parameter for the low temperature regime.

This work presents a simple fan model that is based on the actuator disk approximation, and the blade element and vortex theory of a propeller. A set of equations are derived that require as input the rotational speed of the fan, geometric fan data, and the lift and drag coefficients of the blades. These equations are solved iteratively to obtain the body forces generated by the fan in the axial and circumferential directions. These forces are used as momentum sources in a CFD code to simulate the effect of the fan in an underhood thermal management simulation. To validate this fan model, a fan experiment was simulated. The model was incorporated into the CFD code STAR-CD and predictions were generated for axial and circumferential air velocities at different radial positions and at different planes downstream of the fan. The agreement between experimental measurements and predictions is good.