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Exhaust Emission Control: DPF Systems. Presenter Shingo Iwasaki, NGK Insulators, Ltd.

This technical paper collection covers the Power Cylinder: piston, piston rings, piston pins, and connecting rods. The papers include information on reducing friction and increasing fuel economy, improving durability by understanding wear, and decreasing oil consumption and blow-by.

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 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 The preliminary gas turbine combustor design process uses a huge amount of empirical correlations to achieve more optimized designs. Combustion efficiency, in relation to the basic dimensions of the combustor, is one of the most critical performance parameters. In this study, semi-empirical correlations for combustion efficiencies are examined and correlation coefficients have been revised using an experimental air-blasted tubular combustor that uses JP8 kerosene aviation fuel. Besides, droplet diameter and effective evaporation constant parameters have been investigated for different operating conditions. In the study, it is observed that increased air velocity significantly improves the atomization process and decreases droplet diameters, while increasing the mass flow rate has a positive effect on the atomization—the relative air velocity in the air-blast atomizer increases and the fuel droplets become finer.

The purpose of this SAE Standard is to provide a standardized test procedure for measuring the fuel consumption of spark ignited engines in the range of 225-999cc used in the consumer and commercial turf industry. The load points and associated fuel consumption rates will be measured as the engine operates on the engine speed governor, reflecting how the user will operate the equipment. The fuel consumption calculated in gallons of useage per hour will be derived from a specified engine speed and load map to be communicated universally to end users.

Premixed Charge Compression Ignition (PCCI), a Low Temperature Combustion (LTC) strategy for diesel engines is of increasing interest due to its potential to simultaneously reduce soot and NOx emissions. However, the influence of mixture preparation on combustion phasing and heat release rate in LTC is not fully understood. In the present study, the influence of injection timing on mixture preparation, combustion and emissions in PCCI mode is investigated by experimental and computational methods. A sequential coupling approach of 3D CFD with a Stochastic Reactor Model (SRM) is used to simulate the PCCI engine. The SRM accounts for detailed chemical kinetics, convective heat transfer and turbulent micro-mixing. In this integrated approach, the temperature-equivalence ratio statistics obtained using KIVA 3V are mapped onto the stochastic particle ensemble used in the SRM.

Sources of unburned hydrocarbon (UHC) emissions are examined for a highly dilute (10% oxygen concentration), moderately boosted (1.5 bar), low load (3.0 bar IMEP) operating condition in a single-cylinder, light-duty, optically accessible diesel engine undergoing partially-premixed low-temperature combustion (LTC). The evolution of the in-cylinder spatial distribution of UHC is observed throughout the combustion event through measurement of liquid fuel distributions via elastic light scattering, vapor and liquid fuel distributions via laser-induced fluorescence, and velocity fields via particle image velocimetry (PIV). The measurements are complemented by and contrasted with the predictions of multi-dimensional simulations employing a realistic, though reduced, chemical mechanism to describe the combustion process.

The mixing and combustion processes of short double Diesel injections are investigated by optical diagnostics. A single hole Common Rail Diesel injector allowing high injection pressure up to 120MPa is used. The spray is observed in a high pressure, high temperature cell that reproduces the thermodynamic conditions which exist in the combustion chamber of a Diesel engine during injection. Three configurations are studied: a single short injection serving as a reference case and two double short injections with short and long dwell time (time between the injections). Several optical diagnostics were performed successively. The mixing process is studied by normalized Laser Induced Exciplex Fluorescence giving access to the vapor fuel concentration fields. In addition, the flow fields both inside and outside the jets are characterized by Particle Imaging Velocimetry.

A dual piston Variable Compression Ratio (VCR) engine has been newly developed. This compact VCR system uses the inertia force and hydraulic pressure accompanying the reciprocating motion of the piston to raise and lower the outer piston and switches the compression ratio in two stages. For the torque characteristic enhancement and the knocking prevention when the compression ratio is being switched, it is necessary to carry out engine controls based on accurate compression ratio judgment. In order to accurately judge compression ratio switching timing, a control system employing the Hidden Markov Model (HMM) was used to analyze vibration generated during the compression ratio switching. Also, in order to realize smooth torque characteristics, an ignition timing control system that separately controls each cylinder and simultaneously performs knocking control was constructed.

The objective of this research is a detailed investigation of multiple injections in a highly-dilute diesel low temperature combustion (LTC) regime. This research concentrates on understanding the performance and emissions benefits of multiple injections via experiments and simulations in a 0.48L signal cylinder light-duty engine operating at 2000 r/min and 5.5 bar IMEP. Controlled experiments in the single-cylinder engine are then combined with three computational tools, namely heat release analysis of measured cylinder pressure, a phenomenological spray model using in-cylinder thermodynamics [1], and KIVA-3V Chemkin CFD computations recently tested at LTC conditions [2]. This study examines the effects of fuel split distribution, injection event timing, rail pressure, and boost pressure which are each explored within a defined operation range in LTC.

The objective of this research is a detailed investigation of unburned hydrocarbon (UHC) in a highly-dilute diesel low temperature combustion (LTC) regime. This research concentrates on understanding the mechanisms that control the formation of UHC via experiments and simulations in a 0.48L signal-cylinder light duty engine operating at 2000 r/min and 5.5 bar IMEP with multiple injections. A multi-gas FTIR along with other gas and smoke emissions instruments are used to measure exhaust UHC species and other emissions. Controlled experiments in the single-cylinder engine are then combined with three computational tools, namely heat release analysis of measured cylinder pressure, analysis of spray trajectory with a phenomenological spray model using in-cylinder thermodynamics [1], and KIVA-3V Chemkin CFD computations recently tested at LTC conditions [2].

In this work, a quasi-dimensional, multi-zone combustion model is analytically presented, for the prediction of performance and nitric oxide (NO) emissions of a homogeneous charge spark ignition (SI) engine, fueled with biogas-H2 blends of variable composition. The combustion model is incorporated into a closed cycle simulation code, which is also fully described. Combustion is modeled on the basis of turbulent entrainment theory and flame stretch concepts. In this context, the entrainment speed, by which unburned gas enters the flame region, is simulated by the turbulent burning velocity of a flamelet model. A flame stretch submodel is also included, in order to assess the flame response on the combined effects of curvature, turbulent strain and nonunity Lewis number mixture. As far as the burned gas is concerned, this is treated using a multi-zone thermodynamic formulation, to account for the spatial distribution of temperature and NO concentration inside the burned volume.

This specification and its supplementary detail specifications cover para-aramid materials in the form of thread.

The startability of SI engines, especially of DISI engines, is the greatest challenge when using ethanol blended fuels. The development of a suitable injection strategy is therefore the main engineering target when developing an ethanol engine with direct injection. In order to limit the test efforts of such a program, a vaporization model has been created that provides the quantity of vaporized fuel depending on pressure and on start and end, respectively number and split relation of injections. This model takes account of the most relevant fuel properties such as density, surface tension and viscosity. It also considers the interaction of the spray with cylinder liner, cylinder head and piston. A comparison with test results shows the current status and the need for action of this simulation model.

A multi-zone, direct-injection (DI) diesel combustion model, the so-called RK-model, has been developed and implemented in a full cycle simulation of a turbocharged engine. The combustion model takes into account: transient evolution of fuel sprays, interaction of sprays with swirl and walls, evolution of near-wall flow formed after spray-wall impingement depending on impingement angle and local swirl velocity, interaction of Near-Wall Flows (NWF) formed by adjacent sprays, influence of temperatures of gas and walls in the zones on evaporation rate. In the model the fuel spray is split into a number of specific zones with different evaporation conditions including zone on the cylinder liner and on the cylinder head. The piston bowl is assumed to be a body of revolution with arbitrary shape. The combustion model supports central and non-central injector as well as the side injection system. NOx formation model uses Detail Kinetic Mechanism (199 reactions with 33 species).

Single cylinder optical engines are used for internal combustion (IC) engine research as they allow for the application of qualitative and quantitative non-intrusive, diagnostic techniques to study in-cylinder flow, mixing, combustion and emissions phenomena. Such experimental data is not only important for the validation of computational models but can also provide a detailed insight into the physical processes occurring in-cylinder which is useful for the further development of new combustion strategies such as gasoline homogeneous charge compression ignition (HCCI) and Diesel low temperature combustion (LTC). In this context, it is therefore important to ensure that the performance of optical engines is comparable to standard all-metal engines. A comparison of optical and all-metal engine combustion and emissions performance was performed within the present study.

Two different types of mesh used for diesel combustion with the KIVA-4 code are compared. One is a well established conventional KIVA-3 type polar mesh. The other is a non-polar mesh with uniform size throughout the piston bowl so as to reduce the number of cells and to improve the quality of the cell shapes around the cylinder axis which can contain many fuel droplets that affect prediction accuracy and the computational time. This mesh is specialized for the KIVA-4 code which employs an unstructured mesh. To prevent dramatic changes in spray penetration caused by the difference in cell size between the two types of mesh, a recently developed spray model which reduces mesh dependency of the droplet behavior has been implemented. For the ignition and combustion models, the Shell model and characteristic time combustion (CTC) model are employed.

In the port injected Spark Ignition (SI) engine, the single greatest part load efficiency reducing factor are energy losses over the throttle valve. The need for this throttle valve arises from the fact that engine power is controlled by the amount of air in the cylinders, since combustion occurs stoichiometrically in this type of engine. In WEDACS (Waste Energy Driven Air Conditioning System), a technology patented by the Eindhoven University of Technology, the throttle valve is replaced by a turbine-generator combination. The turbine is used to control engine power. Throttling losses are recovered by the turbine and converted to electrical energy. Additionally, when air expands in the turbine, its temperature decreases and it can be used to cool air conditioning fluid. As a result, load of the alternator and air conditioning compressor on the engine is decreased or even eliminated, which increases overall engine efficiency.

Unburned hydrocarbon (UHC) and carbon monoxide (CO) emission sources are examined in an optical, light-duty diesel engine operating under low load and engine speed, while employing a highly dilute, partially premixed low-temperature combustion (LTC) strategy. The impact of engine load and charge dilution on the UHC and CO sources is also evaluated. The progression of in-cylinder mixing and combustion processes is studied using ultraviolet planar laser-induced fluorescence (UV PLIF) to measure the spatial distributions of liquid- and vapor-phase hydrocarbon. A separate, deep-UV LIF technique is used to examine the clearance volume spatial distribution and composition of late-cycle UHC and CO. Homogeneous reactor simulations, utilizing detailed chemical kinetics and constrained by the measured cylinder pressure, are used to examine the impact of charge dilution and initial stoichiometry on oxidation behavior.