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Abstract Exhaust manifolds are one of the most important components on the engine assembly, which is mounted on engine cylinder head. Exhaust manifolds connect exhaust ports of cylinders to the turbine for turbocharged diesel engine therefore they play a significant role in the performance of engine system. Exhaust manifolds are subjected to very harsh thermal loads; extreme heating under very high temperatures and cooling under low temperatures. Therefore designing a durable exhaust manifold is a challenging task. Computer aided engineering (CAE) is an effective tool to drive an exhaust manifold design at the early stage of engine development. Thus advanced CAE methodologies are required for the accurate prediction of temperature distribution. However, at the end of the development process, for the design verification purposes, various tests have to be carried out in engine dynamometer cells under severe operating conditions.

Abstract Gasoline particulate filters (GPFs) are important aftertreatment components that enable gasoline direct injection (GDI) engines to meet European Union (EU) 6 and China 6 particulate number emissions regulations for nonvolatile particles greater than 23 nm in diameter. GPFs are rapidly becoming an integral part of the modern GDI aftertreatment system. The Active Exhaust Tuning (EXTUN) Valve is a butterfly valve placed in the tailpipe of an exhaust system that can be electronically positioned to control exhaust noise levels (decibels) under various vehicle operating conditions. This device is positioned downstream of the GPF, and variations in the tuning valve position can impact exhaust backpressures, making it difficult to monitor soot/ash accumulation or detect damage/removal of the GPF substrate. The purpose of this work is to present a unique example of subsystem control and diagnostic architecture for an exhaust system combining GPF and EXTUN.

Abstract The effects of exhaust emissions on public welfare have prompted the US Environmental Protection Agency to take various actions toward understanding, modeling, and reducing air pollution from vehicles. This study was performed to better understand exhaust emissions of heavy-duty diesel-powered tractor-trailer trucks that operate in drayage service, which involves the moving of shipping containers to or from port terminals. The study involved the use of portable emissions measurement systems (PEMS) to measure both gaseous and particulate matter (PM) mass emission rates and record various vehicle and engine parameters from the test trucks as they performed their normal drayage service. These measurements were supplemented with port terminal gate entry/exit logs for all drayage trucks entering the two Port of Houston Authority container terminals.

Abstract Although ground grading is one of the most common tasks that hydraulic excavators perform in typical work sites, proper grading is not easy for less-skilled operators as it requires coordinated manipulation of multiple hydraulic cylinders. In order to help alleviate this difficulty, automated grading systems are considered as an effective alternative to manual operations of hydraulic excavators. In this article, a sliding mode controller design is presented for automated grading control of a hydraulic excavator. First, an excavator manipulator model is developed in Simulink by using SimMechanics and SimHydraulics toolboxes. Then, a sliding mode controller is designed to control the manipulator to trace a predefined trajectory for a grading task. For a comparison study, a PI controller is used to control the manipulator to perform a grading task following the same desired trajectory and the performance is compared with those obtained by the sliding mode controller.

Abstract Particulates are a major source of emission from diesel engine. They consist of particles of carbon, sulfates, oil, fuel, and water. These constituents are measured by filtering a sample diluted in a partial- or full-flow tunnel and weighing them. It is a general trend for measuring particulate matter (PM) on cycle basis. But 1-D simulation needs complete PM 3-D contour map considering all engine operating region. It is very tedious work for generating PM on each steady-state point on engine test bed. Hence, Filter smoke meter or opacimeter measurements can be used for estimating PM. Filter smoke meters measured the light reflected from a filter paper through which a known volume of exhaust gas was passed. Opacity meters measure light absorbed by a standard column of exhaust. Both equipments measure visible black smoke comparatively at lower expenditure cost. They are designed to control measurement noise, resolution and repeatability with acceptable accuracy level.

Abstract Reactivity-controlled compression ignition (RCCI) is a dual fuel low temperature combustion (LTC) strategy which results in a wider operating load range, near-zero oxides of nitrogen (NOx) and particulate matter (PM) emissions, and higher thermal efficiency. One of the major shortcomings in RCCI is a higher unburned hydrocarbon (HC) and carbon monoxide (CO) emissions. Unlike conventional combustion, aftertreatment control of HC and CO emissions is difficult to achieve in RCCI owing to lower exhaust gas temperatures. In conventional RCCI, an early direct injection (DI) of low volatile diesel fuel into the premixed gasoline-air mixture in the combustion chamber results in charge stratification and fuel spray wall wetting leading to higher HC and CO emissions. To address this limitation, a homogeneous charge reactivity-controlled compression ignition (HCRCCI) strategy is proposed in the present work, wherein the DI of diesel fuel is eliminated.

Abstract Addition of hydrogen to hydrocarbons in premixed turbulent combustion is of technological interest due to their increased reactivity, flame stability and extended lean extinction limits. However, such flames are a challenge to reaction modelling, especially as the strong preferential diffusion effects modify the physical processes, which are of importance even for highly turbulent high-pressure conditions. In the present work, Reynolds-averaged Navier-Stokes (RANS) modelling is carried out to investigate pressure and hydrogen content on methane/hydrogen/air flames.

Abstract The wide application of Gasoline Direct Injection (GDI) engines and the increasingly stringent Particulate Matter (PM) and Particulate Number (PN) regulations make Gasoline Particulate Filters (GPFs) with high filtration efficiency and low pressure drop highly desirable. However, due to the specifics of GDI operation and GDI PM, the design of these filters is even more challenging as compared to their diesel counterparts. Computational Fluid Dynamics (CFD) studies have been shown to be an effective way to investigate filter performance. In particular, our previous two-dimensional (2D) CFD study explicated the pore size and pore-size distribution effects on GPF filtration efficiency and pressure drop. The “throat unit collector” model developed in this study furthers this work in order to characterize the GPF wall microstructure more precisely.

Abstract This study shows the development of low-temperature and high-temperature reactions in a gasoline-fuelled compression ignition (GCI) engine realizing partially premixed combustion for high efficiency and low emissions. The focus is how the ignition occurs during the low- to high-temperature reaction transition and how it varies due to single- and double-injection strategies. In an optically accessible, single-cylinder small-bore diesel engine equipped with a common-rail fuel injection system, planar laser-induced fluorescence (PLIF) imaging of formaldehyde (HCHO-PLIF), hydroxyl (OH-PLIF), and fuel (fuel-PLIF) has been performed. This was complemented with high-speed imaging of combustion luminosity and chemiluminescence imaging of cool flame and OH*.

Abstract In order to meet the worldwide increasingly stringent particulate matter (PM) and particulate number (PN) emission limits, the diesel particulate filter (DPF) is widely used today and has been considered to be an indispensable feature of modern diesel engines. To estimate the soot loading amount in the DPF accurately and in real-time is a key function of realizing systematic and efficient applications of diesel engines, as starting the thermal regeneration of DPF too early or too late will lead to either fuel economy penalty or system reliability issues. In this work, an open-loop and on-line approach to estimating the DPF soot loading on the basis of soot mass balance is developed and experimentally investigated, through establishing and combining prediction models of the NOx and soot emissions out of the engine and a model of the catalytic soot oxidation characteristics of passive regeneration in the DPF.

Abstract One of the key factors for accurate mass burn fraction and energy conversion point calculations is the accuracy of the compression ratio. The method presented in this article suggests a workflow that can be applied to determine or correct the compression ratio estimated geometrically or measured using liquid displacement. It is derived using the observation that, in a motored engine, the heat losses are symmetrical about a certain crank angle, which allows for the derivation of an expression for the clearance volume [1]. In this article, a workflow is implemented in real time, in a current production engine indicating system. The goal is to improve measurement data quality and stability for the energy conversion points calculated during measurement procedures. Experimental and simulation data is presented to highlight the benefits and improvement that can be achieved, especially at the start of combustion.

Abstract An in-cylinder combustion analysis and a computational fluid dynamics (CFD) coolant flow analysis were performed using AVL FIRE software, which provided the heat transfer boundary conditions (HTBCs) to the temperature field calculation of the cylinder head. Based on the measured material performance parameters such as stress-strain curve under different temperatures and E-N curve, creep, and oxidation data material performance, the cylinder head-gasket-cylinder block finite element analysis (FEA) was performed. According to the temperature field calculation results, the maximum temperature of the cylinder head is 200°C that is within the limit of ALU material. The temperature of the water is more than 21.1°C below the critical burnout point temperature. The high-cycle fatigue (HCF) and thermal-mechanical fatigue (TMF) analysis of the cylinder head were performed by FEMFAT software.

Abstract Direct dual fuel stratification (DDFS) strategy benefits the advantages of the RCCI and PPC strategies simultaneously. DDFS has improved control over the heat release rate, by injecting a considerable amount of fuel near TDC, compared to RCCI. In addition, the third injection (near TDC) is diffusion-limited. Consequently, piston bowl geometry directly affects the formation of emissions. The modified piston geometry was developed and optimized for RCCI by previous scholars. Since all DDFS experimental tests were performed with the modified piston profile, the other piston profiles need to be investigated for this strategy. In this article, first, a comparative study between the three conventional piston profiles, including the modified, stock, and scaled pistons, was performed. Afterward, the gasoline injector position was shifted to the head cylinder center for the stock piston. NOX emissions were improved; however, soot was increased slightly.

Abstract Particulate Matter (PM) is one of the most sought-after exhaust emissions from Heavy-Duty Diesel Engines (HDDEs) to reduce. Several regulations in Europe and North America have led the way in drastically reducing PM of both on-road and off-road engines through stringent adoption of Diesel Particulate Filters (DPFs) and advanced combustion techniques. The effects of these advanced aftertreatment systems were studied using standardized testing procedures and equipment. While PM is defined as a “single” criteria pollutant, its complex structure entails several chemical compounds and molecules, displaying a whole spectrum of particle sizes. In addition, the morphology of some volatile compounds is shown to be affected by the interaction with background air during exhaust dilution and cooling.

Abstract Diesel engines are an important technology for transportation of both people and goods. However, historically they have suffered a significant downside of high soot and nitrogen oxides (NOx) emissions. Recently, ducted fuel injection (DFI) has been demonstrated to attenuate soot formation in compression-ignition engines and combustion vessels by 50% to 100%. This allows for diesel engines to be run at low-NOx emissions that would have otherwise produced significantly more soot due to the soot/NOx tradeoff. Currently the root causes of this soot attenuation are not well understood. To be able to better optimize DFI for use across a variety of engines and conditions, it is important to understand clearly how it works. This study expands on the current understanding of DFI by using numerical modeling under nonreacting conditions to provide insights about the roles of entrainment and mixing that would have been much more challenging to obtain experimentally.

Abstract Diesel engines include systems for cooling, lubrication, and fuel injection and contain a variety of components. A malfunction in any of the engine systems or the presence of any faulty element influences engine performance and deteriorates its components. This research is concerned with the untimely appearance of vital cracks in the liners of a turbocharged heavy-duty Diesel engine. To find the root causes for premature failure, rigorous examinations through visual observations, material characterization, and metallographic investigations are performed. These include Scanning Electron Microscope (SEM) and Energy-Dispersive Spectroscopy (EDS), fracture mechanics analysis, and performance examination, which are also followed by Finite Element Moldings. To find the proper remedy to resolve the problem, drawing a precise and reliable picture of the engine’s operating conditions is required.

Abstract Cavitation erosion caused by high-frequency vibrating walls can appear in the cooling circuit of internal combustion engines along the liners. The vibrations caused by the mechanical forces acting on the crank drive can lead to temporary regions of low pressure in the coolant with local vapor formation, and vapor collapse close to the liner walls leads to erosion damage, which can strongly reduce the lifetime of the entire engine. The experimental investigation of this phenomenon is so time consuming and expensive, which it is usually not feasible during the design phase. Therefore, numerical tools for erosion damage prediction should be preferred. This study presents a numerical workflow for the prediction of cavitation erosion damages by coupling a three-dimensional (3D) Multi-Body-Dynamic (MBD) simulation tool with a 3D Computational Fluid Dynamics (CFD) solver.

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 This work presents a numerical study of the performance and nitrogen oxides (NOx) emissions of a conventional ethanol engine converted to work as a flex-fuel nonconventional architecture: the Split-Cycle Engine (SCE). For this study, the conventional engine fueled with hydrous ethanol was modeled and validated with data from experimental tests. Then the model was converted to operate as an SCE with two compressors and two expanders and simulated with a progressive downsizing of the compressors of the SCE. When the swept volume of the compressors was reduced to 87% of that of the expanders, the thermal conversion efficiency increased by 3.3%. Because of this, the downsized SCE was submitted to simulation runs using two different fuels: hydrous ethanol (H100) and an indolene-ethanol blend (H85). The results of the simulations were compared to the experimental results of the conventional engine.