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Abstract Driving schedule of every vehicle involves transient operation in the form of changing engine speed and load conditions, which are relatively unchanged during steady-state conditions. As well, the results from transient conditions are more likely to reflect the reality. So, the current research article is focused on analyzing the biofuel-like lemon peel oil (LPO) behavior under real-world transient conditions with fuel injection parameter MAP developed from steady-state experiments. At first, engine parameters and response MAPs are developed by using a response surface methodology (RSM)-based multi-objective optimization technique. Then, the vehicle model has been developed by incorporating real-world transient operating conditions. Finally, the developed injection parameters and response MAPs are embedded in the vehicle model to analyze the biofuel behavior under transient operating conditions.

Abstract The use of appropriate loads and regulations is of great importance in weld fatigue assessment of rail on-track maintenance equipment and similar vehicles for optimized design. The regulations and available loads, however, are often generalized for several categories, which proves to be overly conservative for some specific categories of machines. EN (European Norm) and AAR (Association of American Railroads) regulations play a pivotal role in determining the applicable loads and acceptance criteria within this study. The availability of track-induced fatigue load data for the cumulative damage approach in track maintenance machines is often limited. Consequently, the FEA-based validation of rail track maintenance equipment often resorts to the infinite life approach rather than cumulative damage approach for track-induced travel loads, resulting in overly conservative designs.

Abstract The two-branch exhaust of an asymmetric twin-scroll turbocharged engine are asymmetrically and periodically complicated, which has great impact on turbine matching. In this article, a matching effect of turbine speed parameter on asymmetric twin-scroll turbines based on the exhaust pulse energy weight distribution of a heavy-duty diesel engine was introduced. First, it was built as an asymmetric twin-scroll turbine matching based on exhaust pulse energy distribution. Then, by comparing the average matching point and energy matching points on the corresponding turbine performance map, it is revealed that the turbine speed parameter of energy matching points was a significant deviation from the turbine speed parameter under peak efficiency, which leads to the actual turbine operating efficiency lower than the optimal state.

Abstract Asymmetric twin-scroll turbocharging technology, as one of the effective technologies for balancing fuel economy and nitrogen oxide emissions, has been widely studied in the past decade. In response to the ever-increasing demands for improved fuel efficiency and reduced exhaust emissions, extensive research efforts have been dedicated to investigating various aspects of this technology. Researchers have conducted both experimental and simulation studies to delve into the intricate flow mechanism of asymmetric twin-scroll turbines. Furthermore, considerable attention has been given to exploring the optimal matching between asymmetric twin-scroll turbines and engines, as well as devising innovative flow control methods for these turbines. Additionally, researchers have sought to comprehend the impact of exhaust pulse flow on the performance of asymmetric twin-scroll turbines.

Abstract Heavy-duty on-road engines are expected to conform to an ultralow NOx (ULNOx) standard of 0.027 g/kWh over the composite US heavy-duty transient federal test procedure (HD-FTP) cycle by 2031, a 90% reduction compared to 2010 emissions standards. Additionally, these engines are expected to conform to Phase 2 greenhouse gas regulations, which require tailpipe CO2 emissions under 579 g/kWh. This study experimentally demonstrates the ability of high fuel stratification gasoline compression ignition (HFS-GCI) to satisfy these emissions standards. Steady-state and transient tests are conducted on a prototype multi-cylinder heavy-duty GCI engine based on a 2010-compliant Cummins ISX15 diesel engine with a urea-SCR aftertreatment system (ATS). Steady-state calibration exercises are undertaken to develop highly fuel-efficient GCI calibration maps at both cold-start and warmed up conditions.

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Abstract In urban roads the engine speed and the load vary suddenly and frequently, resulting in increased exhaust emissions. In such operations, the effect of air injection technique to access the transient response of the engine is of great interest. The effectiveness of air injection technique in improving the transient response under speed transient is investigated in detail [1]; however, it is not evaluated for the load transients. Load step demand of the engine is another important event that limits the transient response of the turbocharger. In the present study, response of a heavy-duty turbocharged diesel engine is investigated for different load conditions. Three cases of load transients are considered: constant load, load magnitude variation, and load scheduling. Air injection technique is simulated and after optimization of injection pressure based on orifice diameter, its effect on the transient response is presented.

Abstract A modelling tool has been developed for the prediction of fuel effects on the performance and exhaust emissions of a heavy-duty diesel engine. Recurrent neural network models with duty-cycle, engine control, and fuel property parameters as inputs were trained with transient test data from a 15-liter heavy-duty diesel engine equipped with a common-rail fuel injection system and a variable geometry turbocharger. The test fuels were formulated by blending market diesel fuels, refinery components, and biodiesel to provide variations in preselected fuel properties, namely, hydrogen-to-carbon (H/C) ratio, oxygen-to-carbon (O/C) ratio, derived cetane number (CN), viscosity, and mid- and end-point distillation parameters. Care was taken to ensure that the correlation between these fuel properties in the test fuel matrix was minimized to avoid confounding model input variables.

Abstract Commercial vehicles require advanced engine and aftertreatment (AT) systems to meet upcoming nitrogen oxides (NOx) and carbon dioxide (CO2) regulations. This article focuses on the development and calibration of a model-based controller (MBC) for an advanced diesel AT system. The MBC was first applied to a standard AT system including a diesel particulate filter (DPF) and selective catalytic reduction (SCR) catalyst. Next, a light-off SCR (LO-SCR) was added upstream of the standard AT system. The MBC was optimized for both catalysts for a production engine where the diesel exhaust fluid (DEF) was unheated for both SCRs. This research shows that the tailpipe (TP) NOx could be reduced by using MBC on both catalysts. The net result was increased NOx conversion efficiency by one percentage point on both the LO-SCR and the primary SCR. The CO2 emissions were slightly reduced, but this effect was not significant.

Abstract Heavy-duty (HD) engines for sale in the United States must be demonstrated to emit below allowable criteria and particulate emission limits over the operational load and speed cycle specified by the Federal Test Procedure (FTP) Heavy-Duty certification test. The inherently nonlinear load response of internal combustion engines tends to increase torque variability during the most dynamic portions of the test cycle. This clouds assessment of engine developments intended to improve transient performance and leads to frequent invalidation of certification tests. This work sought to develop and evaluate test torque control strategies that reduce this variability. Several load-control algorithms were evaluated for this purpose using a Cummins ISX15 HD diesel engine loaded with a transient alternating current (AC) dynamometer.

Abstract In the recent period, lean-burn gas operation has been gaining large attention both in the marine sector and for power generation since it allows to achieve very low Nitrogen Oxides (NOx) emissions and to reduce carbon footprint compared to conventional diesel engines. However, to ensure a stable and efficient combustion process, innovative ignition systems able to deliver high energy content have to be considered. The employment of an active Pre-Combustion Chamber (PCC) ignition system is nowadays considered one of the most effective solutions for large-bore gas engines. In active PCC engines, the lean gas mixture in the Main Chamber (MC) is ignited by hot jets flowing from the PCC, resulting from a near-stoichiometric gas spark-assisted combustion in the PCC.

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Abstract Due to their high strength and good flexibility, wire ropes are widely used in various intense applications. A wire rope will present complex wave mechanics, especially under impact conditions. In this article, wire ropes (steel core rope and hemp core rope alternately twisted) were used to study the wave dynamic response of steel wire ropes with preload shock. The transmission law of wire rope shock waves was obtained through actual measurements. The results showed that the compression wave and shear wave were generated and propagated along the rope after impact. The conduction of shear waves had significant reflection characteristics, and the reflected waves overlapped with each other. The conduction velocity of the impact shear wave of the steel core wire rope increased with increasing pretension. The peak tension caused by impact decayed exponentially.

Abstract HVAC systems of passenger cars and especially their air purification performance got more and more in focus during the last years. One reason is the overall increased attention to air quality and its effect on human health. Recently, the WHO further tightened the recommended values for many pollutants. This will likely intensify the trend to more complex systems for improving the air purification functionalities. But, up to now there is no standard method for air purification performance testing. Existing standards cover the vehicle cabin air quality only regarding material emissions. Several studies address assessing the performance of air purification functionalities in most cases by real driving tests typically performed in urban areas. This approach results in proper values for the basic efficiency of single systems.

Abstract Vehicle interior air quality is usually determined by the levels of in-cabin air pollutants, such as particulate matter (PM), gaseous air pollution (volatile organic compounds [VOCs], oxides of nitrogen [NOx], and carbon monoxide [CO]), and carbon dioxide [CO2], which reflect the freshness of indoor air. Nowadays, cabin air filters play a key role in preventing outdoor air pollutants transporting inside vehicles; hence, in-cabin air quality can be strongly associated with the filtration performance of cabin air cleaning solutions. However, challenges are existing in a standard method for assessing the performance of a cabin air filter in real-life driving conditions. This study is to develop a low-cost mobile test method for monitoring in-vehicle PM and CO2 and evaluating the performances of cabin air filters while driving the vehicles. The results reveal that certain boundary conditions are important to have a proper method for evaluating the particle removal efficiency.

Abstract Compressed natural gas (CNG) is a promising alternative fuel for compression ignition (CI) engines under dual-fuel (DF) mode operation. Its application on commercial heavy-duty multicylinder diesel engines is scarcely reported, and its potential usage is investigated through a research study. The focus of this research was to study the in-cylinder combustion and its effect on emissions with an increasing energy fraction of CNG at different speeds (1000 rpm-2500 rpm) and load conditions (Speed-Torque mode), inducted through the intake manifold at different mass flow rates ranging from 0.67 kg/h to 4.0 kg/h corresponding to an energy substitution rate (ESR) of 1.9%-60.2% while using diesel as pilot fuel. In-cylinder pressure, heat release rate (HRR), and pressure rise rate (PRR) increased with the increase in CNG mass flow rate (CMFR). Combustion duration is prolonged under diesel-CNG DF (DDF) mode while ignition delay (ID) is reduced with an increase in CNG flow rate.

Abstract Numerical simulation represents a fundamental tool to support the development process of new propulsion systems. In the field of large-bore dual-fuel (DF) engines, the engine simulation by means of fast running numerical models is nowadays essential to reduce the huge effort for testing activities and speed up the development of more efficient and low-emissions propulsion systems. However, the simulation of the DF combustion by means of a zero-dimensional/one-dimensional (0D/1D) approach is particularly challenging due to the combustion process evolution from spray autoignition to turbulent flame propagation and the complex interaction between the two fuels. In this regard, in this activity a 0D/1D multi-zone DF combustion model was developed for the simulation of the combustion process in large-bore DF engines.

Abstract Compressed Natural Gas (CNG) is a promising alternative fuel for application in diesel engines operating on dual-fuel mode. However, its application for a commercial heavy-duty engine has been limited due to difficulty in modification and in altering the engine control unit (ECU) settings. In this investigation, an attempt has been made to optimize the CNG flow rate for different speed and load conditions for operating a commercial heavy-duty turbocharged intercooled engine under diesel-CNG dual fuel based on engine performance and emission parameters on an eddy current engine dynamometer. CNG was inducted through the intake manifold at varying mass flow rates of 0.65-4.0 kg/hr for different speed and load conditions while operating the engine at the Speed/Torque (NT) mode of the dynamometer-engine control.

Abstract The application of compressed natural gas (CNG) as fuel for compression ignition (CI) engines under dual-fuel (DF) mode operation is not attempted in countries like India for commercial purposes. A commercial heavy-duty turbocharged six-cylinder common-rail direct-injected diesel engine has been converted into a DF mode of operation using CNG and diesel for its potential usage and study on its performance along with Selective Catalytic Reduction (SCR). CNG is inducted through the intake manifold at varying energy substitution rates (ESR) with a flow rate of 0.67-1.54 kg/h while diesel fuel is controlled through the engine electronic control unit (ECU). For a maximum ESR of 10.2% with CNG, an increase in power by 8.9% and a 5.8% increase in torque were observed. While there was an increase in brake thermal efficiency (BTE), volumetric efficiency marginally decreased, therefore, to have higher brake power with a DF engine, a dedicated turbocharging system is necessary.