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Abstract The water droplet erosion (WDE) on high-speed rotating wheels appears in several engineering fields such as wind turbines, stationary steam turbines, fuel cell turbines, and turbochargers. The main reasons for this phenomenon are the high relative velocity difference between the colliding particles and the rotor, as well as the presence of inadequate material structure and surface parameters. One of the latest challenges in this area is the compressor wheels used in turbochargers, which has a speed up to 300,000 rpm and have typically been made of aluminum alloy for decades, to achieve the lowest possible rotor inertia. However, while in the past this component was only encountered with filtered air, nowadays, due to developments in compliance with tightening emission standards, various fluids also collide with the spinning blades, which can cause mechanical damage.

Abstract This study underscores the benefits of refining the intralogistics process for small- to medium-sized manufacturing businesses (SMEs) in the engineer-to-order (ETO) sector, which relies heavily on manual tasks. Based on industrial visits and primary data from six SMEs, a new intralogistics concept and process was formulated. This approach enhances the value-added time of manufacturing workers while also facilitating complete digital integration as well as improving transparency and traceability. A practical application of this method in a company lead to cutting its lead time by roughly 11.3%. Additionally, improved oversight pinpointed excess inventory, resulting in advantages such as reduced capital needs and storage requirements. Anticipated future enhancements include better efficiency from more experienced warehouse staff and streamlined picking methods. Further, digital advancements hold promise for cost reductions in administrative and supportive roles.

Abstract Pre-chamber jet ignition technologies have been garnering significant interest in the internal combustion engine field, given their potential to deliver shorter burn durations, increased combustion stability, and improved dilution tolerance. However, a clear understanding of the relationship between pre-chamber geometry, operating condition, jet formation, and engine performance in light-duty gasoline injection engines remains under-explored. Moreover, research specifically focusing on high dilution levels and passive pre-chambers with optical accessibility is notably scarce. This study serves to bridge these knowledge gaps by examining the influence of passive pre-chamber nozzle diameter and dilution level on jet formation and engine performance.

Abstract The use of data-driven algorithms for the integration or substitution of current production sensors is becoming a consolidated trend in research and development in the automotive field. Due to the large number of variables and scenarios to consider; however, it is of paramount importance to define a consistent methodology accounting for uncertainty evaluations and preprocessing steps, that are often overlooked in naïve implementations. Among the potential applications, the use of virtual sensors for the analysis of solid emissions in transient cycles is particularly appealing for industrial applications, considering the new legislations scenario and the fact that, to our best knowledge, no robust models have been previously developed.

Abstract Exhaust emission standards for road vehicles require on-board diagnostics (OBD) of all comprehensive powertrain components (CCMs) impacting pollutant emissions. The legislation defines the generic malfunction criteria and pollutant threshold limits to trigger the component functional degradation. The electric drivetrain in xEV (more than one propulsion energy converter) applications substitutes or supports the internal combustion engine (ICE) operation with electric machine (EM) power. Malfunctions in the electric drivetrain will lead to an increase in ICE power demand. Hence, the electric drive system is classified as a comprehensive component in the OBD legislation. The regulation defines monitoring of the EM performance. The malfunctions that could prevent the EM(s) from properly operating emission control strategies, including any ICE control activation or electric drivetrain performance degradation, should be monitored by the OBD system.

Abstract In this study, a numerical investigation of different premixed gaseous injection strategies was performed to understand their impact on the scavenging and mixture formation of an air-fuel premixed pre-chamber with high exhaust gas recirculation (EGR) operations. EGR dilution is effective for reducing coolant heat loss, pumping work at throttled conditions, and mitigates knock at high-load conditions, thus increasing engine efficiency. To further extend the EGR limit of an air-fuel premixed pre-chamber engine, the effects of different injection strategies (including timing, duration, pressure, pre-chamber volume, and hardware) on the EGR level, trap efficiency, and parasitic loss were determined. Regardless of injection duration and upstream pressure, injecting too early not only increased the amount of the injected premixed gas leaking into the main chamber but also was inefficient in reducing the EGR level in the pre-chamber.

Abstract Letter from the Special Issue Editors

Abstract Reactivity controlled compression ignition (RCCI) is a potential low-temperature combustion (LTC) technique for running intrinsically efficient compression ignition engines while reducing the oxides of nitrogen (NOx) and particulate matter (PM) emissions. However, poor low-load combustion efficiency is a major challenge in the RCCI strategy. In this work, a combination of injection strategy and cold and hot exhaust gas recirculation (EGR) strategies were investigated to improve the low-load combustion efficiency of a production light-duty compression ignition engine operating in the gasoline-diesel dual-fuel RCCI mode. The engine was operated at a low load of 3 bar gross indicated mean effective pressure and at an engine speed of 1500 rpm with wide ranges of single and multiple fuel injection strategies. Significant improvement in combustion efficiency was achieved by targeting the directly injected diesel fuel in the piston lip region.

Abstract Using a compression engine with dual fuel is the most promising technology to control emissions and for fuel economy, to meet the upcoming legislative norms. This experimental study was conducted to understand the effect of fuel reactivity on engine performance and emission in a compression ignition (CI) engine. The effect of injection timing, gasoline ratio, and exhaust gas recirculation (EGR) rate on emission is compared to the conventional diesel engine. In this study, high-octane fuel (gasoline) is injected manifold the intake of a diesel engine (high-reactivity fuel) to primarily investigate the effects of balance between fuels having low and high reactivity. Fuel reactivity is optimized on different load and speed conditions by varying the diesel and gasoline quantity. Experimental results indicate that dual fuel helps to avoid nitrogen oxides (NOx) and soot trade-off, mitigating both to near-zero values.

Abstract The control of the engine airpath is a constrained multi-objective tracking problem. Multiple control variables including Exhaust Gas Recirculation (EGR) and Variable Nozzle Turbocharger (VNT) valve positions are simultaneously adjusted to accommodate fast, slow, and coupled nonlinear airpath dynamics. This work proposes a Nonlinear Model Predictive Controller (NMPC) that exploits a convex and multi-rate prediction model for the real-time airpath control of a Compression Ignition engine equipped with dual-loop EGR and VNT. The benefits of the approach are verified using a simulation study against a EURO 6 production-line controller and Hardware-in-the-Loop (HiL) implementation using a 480 MHz processor that is comparable to nominal Engine Control Units.

Abstract The current work experimentally and theoretically studied the effect of water injection on improving the performance of three different types of single-cylinder internal combustion engines. The first engine is a four-stroke diesel, the second is a four-stroke gasoline, and the third is a two-stroke gasoline engine. Different amounts of water were injected relative to fuel consumption for the three engines to find how it affected the performance, exhaust gas temperatures, and emissions. Comparing the experimental and theoretical results was done to determine the effect of spraying water on lowering the temperatures of the exhaust gases, increasing the thermal efficiency, and lowering specific fuel consumption. The experimental results for the various tested engines show that, in general, the exhaust gas temperature and gas emission decreases by increasing the mass of water injection; these differences vary based on the engine and the operating conditions.

Abstract A major reduction of greenhouse gas emissions, as well as other toxic emissions, is required to reduce the environmental impact of transportation systems. Renewable fuels, in combination with new internal combustion processes, such as reactivity controlled compression ignition (RCCI), are promising measures to enable this reduction. By combining two fuels with different reactivity, RCCI offers high efficiency and low emissions through homogeneous low-temperature combustion. However, a two-fuel RCCI approach leads to an increased number of adjustable operation parameters, such as injection timing. Optimizing these operation parameters to ensure homogenous combustion is challenging. To that end, optical methods provide temporally and spatially resolved information on mixture formation and combustion to analyze the homogeneity of the process. However, established methods, such as OH* imaging, cannot differentiate between multiple fuels.

Abstract A diesel premixed-charge compression ignition (PCCI) technique was used at low loads at which exhaust temperature makes urea-selective catalytic reduction (SCR) use for nitrogen oxides (NOx) reduction challenging. A fuels matrix to examine the effects of increasing fuel volatility, bio-blendstocks, and cetane number on PCCI was formulated using a near-constant 15% aromatic content. The results showed that PCCI could provide greater than 67% NOx emissions reductions at 1,200 RPM, 3.1 bar indicated mean effective pressure (IMEP), and 2.0 bar IMEP. The filter smoke number (FSN) could also be reduced relative to a conventional diesel combustion (CDC) baseline. The reductions in FSN were more moderate in the order of 40-50%, depending upon the fuel used, IMEP, and combustion phasing (CA50) timing.

Abstract Emissions development work for gasoline aftertreatment systems is often conducted in a laboratory on a chassis dynamometer. In this situation, extractive sample lines are frequently connected to the aftertreatment system before and after various components, such as a three-way catalyst, selective catalytic reduction substrate, and the like. This is done to measure the conversion efficiency of the aftertreatment system components as a function of time. The time series exhaust component concentration data, also referred to as continuous data, are combined with a measure of exhaust volumetric flowrate and used to calculate mass-based emissions. As gasoline powertrains become cleaner and produce lower levels of criteria emissions, the proximity (i.e., colocated or not colocated) of the volumetric flowrate and concentration measurements may affect the accuracy of the overall mass emission calculation.

Abstract Future automotive emission regulations are becoming increasingly dependent on off-cycle (acquired on road and referred to as “real-world”) driving and testing. This was driven in part by the often-observed fact that laboratory emission drive cycles (developed to evaluate a vehicle’s emissions on a chassis dynamometer) may not fully capture the nature of real-world driving. As a result, portable emission measurement systems were developed that could be fit in the trunk of a vehicle, but were relatively large, expensive, and complex to operate. It would be advantageous to have low-cost and simple to operate on-board sensors that could be used in a gasoline powertrain to monitor important criteria emission species, such as NOx. The electrochemical NOx sensor is often used for emissions control systems in diesel powertrains and a proven technology for application to the relatively harsh environment of automotive exhaust.

Abstract To reduce CO2 and pollutant emissions from internal combustion engines worldwide, both electrification and efficiency improvement of internal combustion engines are necessary. Pre-chamber (PC) combustion is one of the promising technologies for realizing the above objectives. This article investigates the ignition specification for the PC system with the swirled orifice layout to extend the stability limit of the lean burn. The computational fluid dynamics (CFD) simulation results showed that the discharge channel would be exposed to the direction-fluctuating velocity, where the discharge channel moves around on the electrode surface of the spark plug (SP) and stays at the electrode gap area without channel stretching. To keep a stable discharge channel against the flow in the PC and promote the initial flame propagation in a short time, the high current coil with a short discharge duration was proposed.

Abstract Demand-Driven Material Requirements Planning (DDMRP) is regarded as a potential method of material management to provide planning and execution performance improvements in variable environments. However, Industry 4.0 refers to the fourth industrial revolution that allows creating a smart manufacturing system by using the new technologies of communication, automation, and digitalization. DDMRP and Industry 4.0 are crucial as new technologies are introduced to companies to improve their performance. Nevertheless, there is an absence of reviews showing the relationships between DDMRP and Industry 4.0. A literature review is used to identify the key constructs of DDMRP and Industry 4.0, and the relationships postulated between them are presented. The main objective of this study is to investigate the relationship between DDMRP and Industry 4.0. The result of this article was a model for integrating the DDMPRP and Industry 4.0 proposed upon a robust theoretical method.

Abstract An integrated electrically heated catalyst (EHC) in the three-way catalyst (TWC) of a gasoline internal combustion engine (ICE) is a promising technology to reduce engine cold-start pollutant emissions. Pre-heating the TWC ensures earlier catalyst light-off of a significant portion of the TWC. In such a case, the engine could readily be operated in a fuel-optimal manner since the engine cold-start emission is efficiently treated by the warmed-up EHC-equipped TWC. Pre-heating the EHC is an effective way to reduce cold-start emissions, among other possible EHC strategies. However, it might not always be possible to use pre-heating if the engine-start time is uncertain. In such a case, pre-heating can be started when the engine start is known with greater confidence and post-heating the catalyst could be followed. It would then be natural to turn off the EHC when the payoff for the electrical energy spent is no longer effective in engine cold-start emission reduction.

Abstract Realizing the potential of the gasoline direct injection (GDI) concept lies in effectively stratifying the charge at different engine operating conditions. This is generally obtained by properly directing the air and fuel through carefully oriented intake port(s) and fuel spray and appropriately changing injection parameters. However, robust methods of charge stratification are essential to extend the lean operating range, particularly in small GDI engines. In this work, a novel piston shape was developed for a 200 cm3, single-cylinder, four-stroke gasoline engine to attain charge stratification. Stratification of charge is achieved even when the fuel was injected early in the intake stroke by a specially shaped wedge on the piston crown that produced twin vortices during compression and physically separated the charge into two sides in the combustion chamber.

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