Refine Your Search




Search Results

Technical Paper

1D Model for Correcting the Rate of Injection Signal Based on Geometry and Temperature Influence

The fuel consumption and emissions of diesel engines is strongly influenced by the injection rate pattern, which influences the in-cylinder mixing and combustion process. Knowing the exact injection rate is mandatory for an optimal diesel combustion development. The short injection time of no more than some milliseconds prevents a direct flow rate measurement. However, the injection rate is deduced from the pressure change caused by injecting into a fuel reservoir or pipe. In an ideal case, the pressure increase in a fuel pipe correlates with the flow rate. Unfortunately, real measurement devices show measurement inaccuracies and errors, caused by non-ideal geometrical shapes as well as variable fuel temperature and fuel properties along the measurement pipe. To analyze the thermal effect onto the measurement results, an available rate measurement device is extended with a flexible heating system as well as multiple pressure and temperature sensors.
Technical Paper

1D Thermo-Fluid Dynamic Simulation of a High Performance Lamborghini V12 S.I. Engine

This paper describes the development and application of the 1D thermo-fluid dynamic research code GASDYN to the simulation of a Lamborghini 12 cylinder, V 60°, 6.2 L automotive S.I. engine. The model has been adopted to carry out an integrated simulation (thermodynamic, fluid dynamic and chemical) of the engine coupled to its intake and exhaust manifolds, in order to predict not only the wave motion in the ducts and its influence on the cylinder gas exchange process, but also the in-cylinder combustion process and the pollutant emission concentration along the exhaust system. The gas composition in the exhaust pipe system is dictated by the cylinder discharge process, after the calculation of the combustion via a thermodynamic multi-zone model, based on a “fractal geometry” approach.
Technical Paper

2-Butanone Laminar Burning Velocities - Experimental and Kinetic Modelling Study

2-Butanone (C4H8O) is a promising alternative fuel candidate as a pure as well as a blend component for substitution in standard gasoline fuels. It can be produced by the dehydrogenation of 2-butanol. To describe 2-butanone's basic combustion behaviour, it is important to investigate key physical properties such as the laminar burning velocity. The laminar burning velocity serves on the one hand side as a parameter to validate detailed chemical kinetic models. On the other hand, especially for engine simulations, various combustion models have been introduced, which rely on the laminar burning velocity as the physical quantity describing the progress of chemical reactions, diffusion, and heat conduction. Hence, well validated models for the prediction of laminar burning velocities are needed. New experimental laminar burning velocity data, acquired in a high pressure spherical combustion vessel, are presented for 1 atm and 5 bar at temperatures of 373 K and 423 K.
Technical Paper

2-D Imaging of Fuel Vapor Concentration in a Diesel Spray via Exciplex-Based Fluorescence Technique

To measure the fuel vapor concentration in an unsteady evaporating spray injected into nitrogen atmosphere, the exciplex-forming method, which produces spectrally separated fluorescence from the liquid and vapor phase, was applied in this study. Two experiments were conducted to investigate the qualitative and quantitative applicability of the technique in a high temperature and high pressure atmosphere during the fuel injection period. One is to examine the thermal decomposition of TMPD dopant at a high temperature and a high pressure nitrogen atmosphere during a short period of time. The other is to calibrate the relationship between fluorescence intensity and vapor concentration of TMPD at different vapor temperatures. And then, the qualitative measurement of fuel vapor concentration distributions in diesel sprays was made by applying the technique.
Technical Paper

2-D Soot Visualization in Unsteady Spray Flame by means of Laser Sheet Scattering Technique

The two-dimensional distribution of a soot cloud in an unsteady spray flame in a rapid compression machine(RCM) was visualized using the laser sheet scattering technique. A 40 mm x 50 mm cross section on the flame axis was illuminated by a thin laser sheet from a single pulsed Nd:YAG laser(wavelength 532 nm). Scattered light from soot particles was taken by a CCD camera via a high speed gated image intensifier. The temporal variation of the scattered light images were presented with the injection pressure as a parameter. The results showed that scattered light was intense near the periphery of the flame tip and that the scattered light becomes weaker significantly and disappears fast after the end of injection as injection pressure is increased. This technique was also applied to the visualization of the two-dimensional distribution of liquid droplets in the non-evaporating spray to correlate it with the soot concentration distribution.
Technical Paper

3-D Numerical Analysis Investigating Distribution of Contact Pressures for a Number of Cylindrical Bearing Axial Profiles When Placed Under Radial Load Conditions

Increased torque values passing from engine to transmission have, increasingly become a problem regarding shaft misalignment. Engineers are restricted with regard to applying ISO standards when investigating bearing life cycles as they tend only to cover normal [radial thrust] load conditions. Depending on the application, the need has arisen for numerical models to determine reduction in normal life cycles due to abnormal running conditions. The Simulia Finite Element package Abaqus v6.7 provides trends in the deformations, contact pressures and their respective distribution. It was found the most efficient profile, with regards to a uniform contact pressure, under both radial and misaligned conditions is the toroidal profile.
Technical Paper

3-D Numerical Study of Flow Mixing in Front of SCR for Different Injection Systems

The urea Selective Catalytic Reduction (SCR) exhaust system has been proved to be the reliable aftertreatment device with the capability of reducing tail pipe NOx emission by 75% to 90%, HC by 50% and Particulate Matter (PM) by 30%. Constrained by increasingly stringent packaging envelope, flow mixing in front of substrate is becoming one of the major concerns to achieve ideal performance of higher NOx conversion and lower ammonia (NH3) slip. Three dimensional CFD simulations are performed in current study to investigate flow mixing phenomenon in a SCR system. First, for a traditional tube injector with single or multiple nozzles, the effects of mass flow rates of injected NH3 and exhaust gas on flow mixing and pressure loss are investigated. Then, a concept of ring shape injector with multiple nozzles are initiated and built for 3-D CFD simulations. The comparisons of flow mixing index and injection pressure are made between two type injectors.
Technical Paper

3-D Numerical Study of Fluid Flow and Pressure Loss Characteristics through a DPF with Asymmetrical Channel size

The main objective of the current paper was to investigate the fluid flow and pressure loss characteristics of DPF substrates with asymmetric channels utilizing 3-D Computational Fluid Dynamics (CFD) methods. The ratio of inlet to outlet channel width is 1.2. First, CFD results of velocity and static pressure distributions inside the inlet and outlet channels are discussed for the baseline case with both forward and reversed exhaust flow. Results were also compared with the regular DPF of same cell structure and wall material properties. It was found that asymmetrical channel design has higher pressure loss. The lowest pressure loss was found for the asymmetrical channel design with smaller inlet channels. Then, the effects of DPF length and filter wall permeability on pressure loss, flow and pressure distributions were investigated.
Technical Paper

3-D PIV Analysis of Structural Behavior of D.I. Gasoline Spray

Three-dimensional behaviors of direct injection (D.I.) gasoline sprays were investigated using 2-D and 3-D particle image velocimetry (PIV) techniques. The fuel was injected with a swirl type injector for D.I. gasoline engines into a constant volume chamber in which ambient pressure was varied from 0.1 to 0.4 MPa at room temperature. The spray was illuminated by a laser light sheet generated by a double-pulsed Nd:YAG laser (wave length: 532 nm) and the succeeding two tomograms of the spray were taken by a high-resolution CCD camera. The 2-D and 3-D velocity distributions of the droplet cloud in the spray were calculated from these tomograms by using the PIV technique. The effects of the swirl groove flows in the injector and the ambient pressure on the structural behavior of the droplet cloud in the spray were also examined.
Technical Paper

3D Beam Forming Measurements Using 3D-Microphone Arrays

Traditional acoustic measurements inside any cavity have historically been conducted with a small number of microphones. By this means it is possible to gain information about parameters like frequencies, orders and sound pressures. However, a space-selective analysis is nearly impossible and it is not feasible to find the position of the sound sources in space in a practical way. While traditional beam forming systems with planar microphone arrays have enlarged the possibilities of acoustic measurements, they do not give comprehensive information about the sound sources in the entire vehicle interior. Therefore, the components of the Acoustic Camera of the GFal were extended by a spherical, acoustically transparent and omni-directional array. A new option is to map onto a common 3D-CAD-model of the object of interest, for instance a vehicle interior. The advantages and disadvantages of 2D- and 3D-mappings will be discussed in the paper.
Technical Paper

3D CFD Model of DI Diesel Low Pressure Fuel Pump System

This paper discusses the holistic approach of simulating a low pressure pump (LPP) including test stand flow dynamics. The simulation includes all lines and valves of the test stand representing realistic test operating conditions in the simulation. The capability to capture all line dynamics enables a robust design against resonances and delivers high-quality performance data. Comparison with actual test data agrees very well giving us confidence in the prediction capability of proposed method and CFD package used in the study. Despite the large spatial extent of the simulation domain, Simerics-MP+ (aka PumpLinx) is able to generate a feasible mesh, together with fast running speed, resulting in acceptable turn-around times. The ability to still model small gaps and clearance of the LPP very efficiently enables inclusion of realistic tolerances as experienced on hardware.
Journal Article

3D Numerical Study of Pressure Loss Characteristics and Soot Leakage Through a Damaged DPF

Diesel Particulate Filters (DPF) are widely used to meet 2007 and beyond EPA Particulate Matter (PM) emissions requirements. During the soot loading process, soot is collected inside a porous wall and eventually forms a soot cake layer on the surface of the DPF inlet channel walls. A densely packaged soot layer and reduced pore size due to Particulate Matter (PM) deposition will reduce overall DPF wall permeability which results in increasing pressure drop across the DPF substrate. A regeneration process needs to be enacted to burn out all the soot collected inside the DPF. Soot mass is not always evenly distributed as the distribution is affected by the flow and temperature distribution at the DPF inlet. As a result, the heat release which is determined by the burn rate is locally dependent. High temperature gradients are often found inside DPF substrate as a result of these locally dependent burn rates.
Technical Paper

3D Simulations And Experimental Validation of High EGR - PHCCI Combustion

The present work addresses the possibility to correctly simulate Partial Homogeneous Charge Compression Ignition (PHCCI) combustion, obtained by the application of EGR up to 60% without using detailed kinetic models. In particular, the laminar and turbulent time characteristic model has been analyzed and improved. The study illustrates the prediction capabilities that can be achieved with such an approach. The paper reports the results obtained from the simulation of a single cylinder research engine and a four-cylinder diesel engine to verify the validity of the proposed method independently of engine geometry and configuration. All numerical results are compared with experimental pressure traces and rates of heat release, as well as with NOx and soot emissions over a wide range of operating conditions. With the modified characteristic time model, realistic simulations of engine combustion up to EGR values of about 60% have been obtained for both engines.
Technical Paper

3D analysis of vapor and liquid phase of GDI injectors using laser induced exciplex fluorescence tomography in a high pressure/high temperature spray chamber

The quality of mixture formation in gasoline direct injection (GDI) engines has a significant influence on combustion, emissions and mileage. A new measurement technique was set up at an optically accessible high pressure / high temperature spray chamber to investigate the spatial mass distribution of vapor and liquid phase in order to optimize the stratified engine operation mode. Therefore a laser light sheet is traversed through the spray, the exciplex fluorescence is detected and the tomography results are quantified by the global information of the injected mass, which allows detailed spray investigations with λ-charts. For spray homogeneity analysis a new method based on histogram calculation is presented allowing grid independent comparison of different injector types.
Technical Paper

3D-CFD Flow Structures in Journal Bearings

Hydrodynamic radial journal bearings under unsteady load, which are common for automotive applications, are exposed to cavitation, e.g. flow, suction, shock and exit cavitation. The fluid mechanic description of the flow in journal bearings takes advantage of the small bearing clearance, which allows the reduction of the Navier-Stokes equations and leads to the Reynolds equation. The Reynolds equation is two-dimensional, the radial pressure gradient and the radial velocity component are neglected. However, the equation includes the surface velocities, oil density and viscosity and describes the relation between hydrodynamic pressure and local clearance. With the introduction of a cavitation index or a mass flow coefficient a powerful method to carry out numerical studies can be created, which allows the calculation of flow properties and the prediction of regions where the lubrication film disintegrates.
Technical Paper

4300 F Thermocouples for Re-Entry Vehicle Applications Part II

This paper presents a discussion of the component evaluation and design development work performed in developing a 4300 F reentry vehicle nose cap temperature sensor. Material compatabilities, insulation resistance, and atmospheric pressure effects on bare wire calibration data are discussed in some detail. The final design is outlined and the application problems discussed. The probe utilizes: a sintered iridium high temperature sheath (4300 F) and platinum 20% rhodium as the low temperature sheath (3000 F); beryllia as insulation -- hard fired at 4300 F and compacted powder at 3000 F; tungsten versus tungsten 26% rhenium as the thermocouple pair.
Technical Paper

4th Generation Diesel Piezo Injector (Realizing Enhanced High Response Injector)

Diesel common rail injectors are required to utilize a higher injection pressure and to achieve higher injection accuracy in order to meet increasingly severe emissions, less fuel consumption, and higher engine performance demand. In addition to those requirements, in conjunction with optimized nozzle geometry, a more rectangular injection rate and stable multiple injections with shorter intervals are required for further emissions and engine performance improvement by optimizing the combustion efficiency.
Technical Paper

5/8 Yard All Hydraulic Hoe

The Harnischfeger hydraulic hoe circuits are designed for fast digging cycles. The circuits have separate pump sections, control valves, cylinders, and motors. There is complete independence of action of all circuits in volume and pressure. The maximum horsepower that can be applied to any circuit is determined by the maximum volume of the pump section and relief setting. Forces that are applied to the structure are controlled by the area of the cylinders, the fixed volume of the motors, and the relief settings. The machine can fill the dipper at full digging depth, hoist to spoil pile height, swing 90deg, dump the load, and return to full depth in 17–22sec. The H312 5/8 yard machine can dig 2cu yd per minute.
Technical Paper

50 Development of Measurement Method for Airborne Sound Emitted by Personal Watercraft

The personal watercrafts (PWC's) are operated in various ways; going around on certain course again and again, repeating acceleration and deceleration, or prolonged idling operation, for instance. The procedure of ISO 14509 has been applied in the traditional sound measurement for powered recreational craft. However, the standard is designed to measure the sound from the typical small crafts, on the assumption that they run straight in a constant speed. It is believed to be inappropriate to use this procedure for the measurement of PWC sound. In trying to establish the suitable procedure for PWC, evaluation by the auditory sense of 15 raters was carried out in parallel with the traditional sound pressure level measurement. As the candidate, four (4) measurement methods were employed in this test. 5 models of PWC's including modified crafts were used. Correlation between the results of traditional sound measurement and the auditory sense ratings was examined.