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Technical Paper

Investigation of the Transient In-Cylinder Flow Inside a Two Stroke Engine with Particle-Image-Velocimetry

2000-03-06
2000-01-0902
In order to meet future emission standards of small two-stroke engines (CARB 2), detailed knowledge of in-cylinder charge motion and mixture distribution is essential to be able to provide new ways of reducing exhaust emissions. The aim is to minimize fuel short circuiting accompanying the scavenging flow, which in turn leads to high HC emissions. Therefore, an experimental investigation was carried out to investigate the in-cylinder flow structure during the gas exchange process inside a small two-stroke engine. An optically accessible cylinder was fitted to a 64 cm3 two-stroke engine and the transient gas motion examined with Particle-Image-Velocimetry (PIV) under a variety of operating conditions and speeds up to 6000 rpm. The flow was investigated in two vertical cross- sectional planes through the cylinder and in a horizontal plane. The flow was observed through endoscopic optics to overcome the limitations associated with the design of an optical aperture in the small engine.
Technical Paper

Investigation of the Transient Oil Consumption of Engine by the Newly Developed Oil Consumption Meter

1986-02-01
860544
A new method of continuous measurement of engine oil consumption using sulfur as the tracer has been developed. The modified non-dispersive-infrared (NDIR) analyzer with the SO2 absorbent and a permeable plastic type dryer enable to measure very low concentration of SO2 in the exhaust gas. By the use of this method, the engine oil consumption under the transient engine operating condition has been analyzed. The experimental result show that the measured value of the transient oil consumption is larger than the estimated value by the quasisteady method using the experimental data of steady-state operations. The difference between these value is explained by the simple model developed here. This model also show that the total oil consumption under the transient engine operating condition depends mainly on the amount of oil drawn into the combustion chamber by the high vacuum during engine-brake conditions.
Technical Paper

Investigation of the Turbulence Modeling Effects on the CFD Predictions of Passenger Vehicle Underhood Airflow

2018-04-03
2018-01-0476
Computational Fluid Dynamics (CFD) tools play an important role in the early stages of vehicle aerothermal development. Arguably, the RANS (Reynolds Averaged Navier-Stokes) approaches are most widely used in industry due to their acceptable accuracy with affordable computational cost and faster turnaround time. In many automotive flows, RANS models cannot very accurately capture the absolute flow features or even the integral force coefficients. In spite of this, the RANS based CFD prediction results can conveniently be used to assess the magnitude and direction of a trend. However, even for such purposes, notable disagreements often exist between the flow features predicted by different RANS turbulence models. Whilst comparisons of different RANS models for various applications are abundant in literature, such evaluations on full-car models are limited, especially the evaluations of the cooling airflow inside the underhood compartment.
Technical Paper

Investigation of the Under-Hood Aero-Thermal Flow Features Using 3D CFD Simulation

2017-03-28
2017-01-0142
The demand for better fuel economy pushed by both consumer and Environmental Protection Agency (EPA), made OEMs to put more effort on other areas beside vehicle external aerodynamics. As one of these areas, under-hood aero-thermal management has taken an important role in the new road vehicle design process, due to the combination of growing engine power demands, utilization of sophisticated under-hood and underbody devices, and emission regulations. The challenge of the under-hood aerothermal management is not only due to the complexity of under-hood compartment, but also as a result of the complex heat transfer phenomena involving conduction, convention and thermal radiation. In this study, 3D CFD simulations were used to investigate the under-hood aerothermal flow features. The full vehicle model with detailed under-hood components used in this study is a Hyundai Veloster. A commercial CDF code Star-CCM+ version 11.04 from CD-adapco was used to run all the simulations.
Technical Paper

Investigation of the Urea Evaporation and Mixing with Various Temperatures and Injector and Injection Angles in the Catalytic Muffler

2013-04-08
2013-01-1078
Diesel engine is being used widely in many industrial fields, as it provides merits in the aspects of higher thermal efficiency and less CO₂ emission. However, NOx regulations for diesel engines are being strengthened and it is impossible to meet the emission standard without aftertreatment systems such as SCR (Selective catalytic reduction), LNC (Lean NOx catalyst), and LNT (Lean NOx trap). Among the NOx reduction aftertreatments, Urea-SCR system is known as the most stable and efficient method to solve the problem of NOx emission. But this device has some issues associated with the ammonia slip phenomenon which is occurred by shortage of evaporation and thermolysis time, and that makes it difficult to achieve uniform distribution of the injected urea.
Technical Paper

Investigation of the Vehicle Ride Vibration Effect on the Driveline Fluctuations

2002-11-18
2002-01-3065
One of the main causes of the torsional and bending fluctuations of the driveline is the angularity of the driveshaft and its universal joints. Most of the previous studies of the driveline vibrations have considered constant and equal angularities of these joints. However, the exact equality of the angularity is very difficult to maintain for ground vehicles under different ride vibration modes. This paper is concerned with the coupling between the driveline fluctuations and the ride vibrations of the rear drive vehicles. The coupled motions, which are; drive axle suspension deformation and vehicle body pitch angle and their derivatives, have been used to study the driveshaft and output shaft bending and torsional fluctuations. The results have showed that the fluctuations of the driveshaft due to the base angularity of the joints are superimposed by another fluctuation due to the bounce and pitch of the vehicle body.
Technical Paper

Investigation of the intake tumble flow in a prototype GDI engine using a steady-state test rig

2001-09-23
2001-24-0022
An experimental and numerical investigation, using the Laser Doppler Anemometry (LDA) technique and a 3D fluid-dynamic code (KIVA 3V), was carried out in a prototype engine under steady-state conditions. The aim of the present activity was the flow field characterization and the effect of the intake geometry on the in-cylinder tumble flow. A new steady flow test rig designed for capturing the tumble motion within a test cylinder, made by a blower and an engine head, was assembled to simulate the intake flow. The engine head was mounted on an aluminum cylinder, having the same bore as the real engine. The cylinder was provided with optical accesses on the periphery and a flat optical window located at the bottom to a depth equal to the stroke of the engine. The cylinder was also equipped with two cylindrical ducts, used as air outflow ports.
Technical Paper

Investigation of the perceived sound quality of an automotive HVAC system

2006-11-21
2006-01-2652
The noise emitted by the heating, ventilation and air conditioning system (HVAC) has a great influence on the car acoustical comfort and quality perception. To improve its sound quality, physical properties which determine the subjective perception have to be identified. The HVAC-noise of twelve cars in different arrangements of fan speed and direction of air flow was recorded for later objective and subjective analysis. All cars were of the same model, but with three different types of HVAC-systems, and had just been manufactured. Objective analysis with sound quality software and subjective evaluations was carried out. Using multiple linear regressions on the subjective data, relations between subjective results and psychoacoustic metrics were determined and models to predict subjective response to HVAC sounds are proposed. It is shown that the annoyance caused by the HVAC-noise can be satisfactorily described by Zwicker's stationary loudness model.
Technical Paper

Investigation of thermally induced die cracking for H13 High Pressure Casting dies using simulation methods

2007-10-30
2007-32-0100
Die cracking is one of the most important life-limiting tool failure mechanisms in high pressure die casting (HPDC). Cracking is caused by thermal shock from sudden heating and then cooling of the die surface. Injection of molten aluminium, transfers heat to the die which results in compressive stresses on the die surface. After the casting has been extracted, the die is sprayed with releasing agent which generates tensile stresses on the surface of the die. These stress fluctuations result in heat check cracking or gross cracking forming on the surface of the die. Casting simulation software was used to simulate the casting process; metal filling the die cavity, solidification and thermal stresses in the die. For this paper a comparison was made between a simulation analysis and a cracked die slide. When the die cracks due to thermal fatigue, aluminium penetrates into the cracks which results in visual defects being formed in the casting and will further reduce the die-life.
Technical Paper

Investigation of vanadium sublimation from SCR catalysts

2015-09-06
2015-24-2503
The aim of the study is to evaluate the possible vanadium emissions from different commercially available vanadium-based SCR monoliths. The vanadium sublimation was studied at laboratory scale using a monolith sample (16 mm diameter × 19 mm long). Vanadia vapors were disposed on an alumina bed placed downstream the catalyst sample, in the hot zone of a furnace. Experiments were carried out with a space velocity of 42 000 h−1. The reactive gas flow was composed of 5%O2, 5%H2O, 500ppm NO and 500ppm NH3. Catalyst samples and alumina bed were exposed to this reactive gas flow during 10 hours at 500°C, 600°C, 650°C, 675°C, 700°C and 750°C, successively. After each test, alumina samples were mineralized from HNO3, HF and HCl mixture. The digests were then diluted with high purity water prior, to ICP-MS analysis. The results revealed that, for full body type catalysts, sublimation of vanadium increases in a significant way from an exposure to the reactive gas flow at 675°C.
Technical Paper

Investigation of ‘Sweep’ Mapping Approach on Engine Testbed

2002-03-04
2002-01-0615
Steady state mapping is fundamental to optimizing IC engine operation. Engine variables are set, a predefined settling time elapses, and then engine data are logged. This is an accurate but time consuming approach to engine testing. In contrast the sweep method seeks to speed up data capture by continuously moving the engine through its operating envelope without dwelling. This is facilitated by the enhanced capability of modern test rig control systems. The purpose of this work is to compare the accuracy and repeatability of the sweep approach under experimental conditions, with that of steady state testing. Limiting factors for the accuracy of the sweep approach fall into two categories. Firstly on the instrumentation side - transducers have a characteristic settling time. Secondly on the engine side - thermal and mechanical inertias will mean that instantaneous measurements of engine parameters differ from the steady state values.
Technical Paper

Investigation of “Thick Grid” Plasma Switches for Thermionic System Output Voltage

1992-08-03
929301
Plasma switches ( Cs and Cs-Ba tacitrons PS ) with thick grid have grid with thickness more than mesh aperture size. These grids have some advantages as compared with small-scale /1.2/ ones, for instance, much more electrical strength. This paper contains the “thick-grid” investigation results; the grid controle efficiency, the plasma parameteres, probe researches of these parameteres at conductive state and their variety during the process of quenching. The results showed the “thick-grid” PS plasma differed from the “thin - grid” PS signyficantly at the stationary state as well as by quenching dynamic features.
Technical Paper

Investigation on Brake Disc Deformation Under Asymmetric Mechanical Loads

2021-10-11
2021-01-1291
The mechanism of automobile brake hot spots is unclear, which is a problem in the brake industry. Complex coupling between friction, heat, contact, and structure is the main difficulty in revealing the mechanism of brake hot spots. This paper proposes a new way to study the mechanism of hot spots by analyzing the deformation behavior of brake discs under asymmetric mechanical loading. The actual brake is simplified into a brake disc and friction lining system, and a transient dynamic finite element model under asymmetric mechanical loads is established to analyze the deformation characteristics of the brake disc. The normal deformation of the brake disc under asymmetric mechanical loads consists of two parts: low-frequency bending deformation and high-frequency waviness deformation, which are caused by the squeezing effect of the asymmetric brake pressure on the brake disc and the constraint modal vibration of the brake disc.
Technical Paper

Investigation on Characteristics of Lean Limit Flame in a Closed Bomb

2001-11-01
2001-28-0011
Form the viewpoint of low air pollution and energy saving in the internal combustion engines, experiments have been carried out to examine the characteristics of flame propagation near the lean limit mixtures in a closed bomb by using the microgravity techinique. The true flame characteristics is examined by realizing the spherical flame propagation in a closed bomb under microgravity. Furthermore, the effect of hydrogen added in lean limit mixtures and improvement of the reflectivity of the internal surface wall of the combustion bomb are studied to enhance the flame propagation speed of lean limit mixtures.
Technical Paper

Investigation on Cold Start for Proton Exchange Membrane Fuel Cell Stack

2021-04-06
2021-01-0738
Cold start remains a major obstacle to the commercialization of proton exchange membrane fuel cell (PEMFC), however, there are few studies on the cold start characteristics, especially at a complicated stack level. In this study, a novel layer-lumped numerical model with higher computational efficiency is proposed to investigate the cold start behavior of PEMFC stack, in which phase transition, heat transfer and electrochemical reaction are comprehensively considered. Besides, phase transition mechanisms are reconstructed based on the assumption that super-cooled water exists within the cell. With this model, the inconsistency of the stack temperature distribution and output performance is presented, some constant loading voltage strategies are investigated, and a linear variable controlling voltage strategy is developed.
Technical Paper

Investigation on Cold Starting and Warming up of Gasoline Engines with EFI

2007-10-30
2007-32-0070
The cold starting and cold-state running cycle (i.e. engine warming up) of gasoline engines are the key points of exhaust emissions formation of modern engines, and also one of the very important targets for the increasingly stringent emissions regulations. The combustion stability in gasoline engine cold starting and warming up will impact the formation of its exhaust emissions. This paper introduces the improvement in cold starting and warming up combustion process for the motorcycle gasoline engine by high-energy, dual-spark plug based rapid burning system. Test results showed that the high-energy, dual-spark plug based rapid burning system was very helpful to rapid ignition under the engine cold starting condition. Meanwhile, because of increasing the burning velocity of the engine mixture, this solution can realize the larger ignition retard and stable combustion process under the engine warming-up condition.
Technical Paper

Investigation on Combustion Stability, Unregulated and Particle Emissions in RCCI Engine

2024-04-09
2024-01-2088
This study experimentally investigates the combustion stability in RCCI engines along with the gaseous (regulated and unregulated) and particle emissions. Multifractal analysis is used to characterize the cyclic combustion variations in the combustion parameters (such as IMEP, CA50, and THR). This analysis aims to investigate the multifractal characteristics of the RCCI combustion mode near the misfiring limit. The investigation is carried out on a modified single-cylinder diesel engine to operate in RCCI combustion mode.The RCCI combustion mode is tested for different diesel injection timing (SOI) at fixed engine speed (1500rpm) and load (1.5 bar BMEP). The particle number characteristics and gaseous emissions are measured using a differential mobility spectrometer (DMS500) and Fourier Transform Infrared Spectroscopy (FTIR) along with Flame Ionizing Detector (FID), respectively.
Journal Article

Investigation on Combustion, Performance and Emissions of Automotive Engine Fueled with Ethanol Blended Gasoline

2016-04-05
2016-01-0886
To tackle the problems associated with the volatility of crude oil prices and ever stringent emission norms, oil industries and automobiles manufacturers are experimenting with various alternative fuels to increase its percentage share in the energy mix and to reduce the vehicular emissions. Alcohols are preferred choice of alternative fuels for the gasoline engines as it does not require any major engine modification and new infrastructure for the fuel distribution network. Ethanol as sole fuel or blending component for gasoline for use in spark ignition engines has been investigated many decades. Currently, 10% ethanol is blended in motor gasoline in India and the ethanol concentration may be further increased in future. In order to study the effect of higher blends of ethanol (upto 20%) on engine in-cylinder combustion, performance and emission, investigations were carried out on a latest generation passenger car engine in a climatic controlled test cell.
Technical Paper

Investigation on Contralateral Lower Extremity Injuries of Pedestrian and E-Bike Rider Based on C-NCAP

2018-04-03
2018-01-1045
Lower extremities are easily injured in traffic accidents. During pedestrian-vehicle crashes, pedestrian lower extremities are subjected to the influence of combined shear force and bending force, which could bring about ligament tear and bone fracture. According to 2018 China New Car Assessment Program (C-NCAP) pedestrian testing protocol, where the flexible pedestrian legform impactor (FLEX-PLI) is struck from the right lateral by vehicle, the injuries of the ipsilateral side leg are taken into account for assessing the performance of lower extremities. However, the contralateral leg injuries and deformation are neglected in the current testing protocol and the pedestrian walking gaits and the e-bike riding scenario have been little consideration. The purpose of this study is to investigate the injury characteristics of the contralateral lower extremities in pedestrian-vehicle and bicyclist-vehicle crashes.
Technical Paper

Investigation on Correlation Between Groan Noise and Coefficient of Friction With Friction Material's Difference

2004-03-08
2004-01-0827
This paper reports the findings of the effect that different friction materials have on the amount of groan noise in the automotive braking system. In order to investigate the pad material's influence on groan noise, a comparison analysis was carried between pads for which a groan noise did occur and pads for which a groan noise did not occur. The comparison analysis results showed that the groan noise was affected by the pad's raw material particle size. It was found that the pad's raw material particle size affected the change in the pad's surface condition. Changed pad surface conditions are related to groan noise. In addition, the friction coefficient (or friction force) for different pad materials was investigated to ascertain the relationship between groan noise and the friction coefficient (or friction force).
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