Refine Your Search

Topic

Search Results

Viewing 1 to 13 of 13
Technical Paper

Research Results and Progress in LeaNOx II -A Co-operation for Lean NOx Abatement

2000-10-16
2000-01-2909
In a consortium of European industrial partners and research institutes, a combination of industrial development and scientific research was organised. The objective was to improve the catalytic NOx conversion for lean burn cars and heavy-duty trucks, taking into account boundary conditions for the fuel consumption. The project lasted for three years. During this period parallel research was conducted in research areas ranging from basic research based on a theoretical approach to full scale emission system development. NOx storage catalysts became a central part of the project. Catalysts were evaluated with respect to resistance towards sulphur poisoning. It was concluded that very low sulphur fuel is a necessity for efficient use of NOx trap technology. Additionally, attempts were made to develop methods for reactivating poisoned catalysts. Methods for short distance mixing were developed for the addition of reducing agent.
Technical Paper

The Magnesium Hatchback of the 3-Liter Car: Processing and Corrosion Protection

2000-03-06
2000-01-1123
The hatchback of Volkswagen's 3 liter car (3 l fuel consumption per 100 km) consists of an inner component of die casting magnesium (AM50) covered with an aluminum panel from the outside. This hybrid design requires a new manufacturing process: The pre-coated magnesium part will be bonded and folded with the bare aluminum part. Corrosion protection is provided by an organic coating system which both protects against general corrosion and galvanic corrosion. The corrosion of the Al / Mg sandwich has been examined with hybrid samples which are similar to the hatchback. Several powder coatings (epoxy resin, polyester resin, hybrid resin), wet paints and cathodic electro-coating paints of different thicknesses and compositions have been applied to the magnesium part. They show that only powder coating provides adequate protection. Galvanic corrosion at the points of attachment of the hatchback might be possible (for example the bolted joint of the hinge).
Technical Paper

Measurement of Wall Film Thickness in the Intake Manifold of a Standard Production SI Engine by a Spectroscopic Technique

1997-10-01
972832
This paper reports on a non-intrusive method for measuring the liquid fuel film thickness in the intake manifold of a series production SI engine with multi-point fuel injection. The technique is based on laser-induced fluorescence. The optical set-up uses a bifurcated optical fibre bundle for transmission of the laser light for excitation of the fluid and for detecting of the fluorescence light. Due to the special design of the optical probe head it is highly sensitive for thin film measurements and it allows the accurate determination of the fuel film thickness even between a few and 100 μm. Special emphasis is placed on the selection of an adequate tracer added to the iso-octane fuel to achieve the correct film thickness even under vaporizing conditions, and on a detailed study of the parameters influencing the evaluated film thickness.
Technical Paper

Validating Prototype Connected Vehicle-to-Infrastructure Safety Applications in Real- World Settings

2018-04-03
2018-01-0025
This paper summarizes the validation of prototype vehicle-to-infrastructure (V2I) safety applications based on Dedicated Short Range Communications (DSRC) in the United States under a cooperative agreement between the Crash Avoidance Metrics Partners LLC (CAMP) and the Federal Highway Administration (FHWA). After consideration of a number of V2I safety applications, Red Light Violation Warning (RLVW), Curve Speed Warning (CSW) and Reduced Speed Zone Warning with Lane Closure Warning (RSZW/LC) were developed, validated and demonstrated using seven different vehicles (six passenger vehicles and one Class 8 truck) leveraging DSRC-based messages from a Road Side Unit (RSU). The developed V2I safety applications were validated for more than 20 distinct scenarios and over 100 test runs using both light- and heavy-duty vehicles over a period of seven months. Subsequently, additional on-road testing of CSW on public roads and RSZW/LC in live work zones were conducted in Southeast Michigan.
Technical Paper

Crank-Angle Resolved Temperature in SI Engines Measured by Emission-Absorption Spectroscopy

1999-10-25
1999-01-3542
Crank-angle resolved, gas temperatures are determined in the combustion chamber of a Volkswagen (VW) standard-production, port-injected SI engine. During idle, two different methods are applied: (1) a direct spectroscopic emission-absorption technique at a resonance line of potassium, seeded to the air stream to generate sufficient spectral absorptance (‘colouring’ technique), and (2) a more standard, indirect method in which temperatures are derived from pressure recordings using a two-zone thermodynamic model. Combustion temperatures obtained during idle with both the spectroscopic (1) and ‘two-zone’ (2) methods are in good agreement. In addition, the spectroscopic technique is extended to transient operating conditions where the ‘two-zone’ method is not applicable. Combustion temperatures measured during cold-start and abrupt load alteration are in good agreement with former investigations.
Journal Article

Analysis of Cycle-to-Cycle Variations of the Mixing Process in a Direct Injection Spark Ignition Engine Using Scale-Resolving Simulations

2016-11-16
2016-01-9048
Since the mechanisms leading to cyclic combustion variabilities in direct injection gasoline engines are still poorly understood, advanced computational studies are necessary to be able to predict, analyze and optimize the complete engine process from aerodynamics to mixing, ignition, combustion and heat transfer. In this work the Scale-Adaptive Simulation (SAS) turbulence model is used in combination with a parameterized lagrangian spray model for the purpose of predicting transient in-cylinder cold flow, injection and mixture formation in a gasoline engine. An existing CFD model based on FLUENT v15.0 [1] has been extended with a spray description using the FLUENT Discrete Phase Model (DPM). This article will first discuss the validation of the in-cylinder cold flow model using experimental data measured within an optically accessible engine by High Speed Particle Image Velocimetry (HS-PIV).
Technical Paper

Feasible Steps towards Improved Crash Compatibility

2004-03-08
2004-01-1167
Compatibility has been a research issue for many years now. It has gained more importance recently due to significant improvements in primary and secondary safety. Using a rigorous approach, combining accident research and theoretical scientific considerations, measures to improve vehicle-vehicle compatibility, with an emphasis on feasibility, were discussed. German accident research statistics showed that frontal impacts are of higher statistical significance than side impacts. Based on this and the high potential for improvement due high available deformation energy, the frontal impact configuration was identified as the most appropriate collision mode for addressing the compatibility issue. In side impacts, accident avoidance was identified as the most feasible and sensible measure. For frontal vehicle-vehicle impacts, both trucks and passenger cars were identified as opponents of high statistical significance.
Journal Article

Impact of a Diesel High Pressure Common Rail Fuel System and Onboard Vehicle Storage on B20 Biodiesel Blend Stability

2016-04-05
2016-01-0885
Adoption of high-pressure common-rail (HPCR) fuel systems, which subject diesel fuels to higher temperatures and pressures, has brought into question the veracity of ASTM International specifications for biodiesel and biodiesel blend oxidation stability, as well as the lack of any stability parameter for diesel fuel. A controlled experiment was developed to investigate the impact of a light-duty diesel HPCR fuel system on the stability of 20% biodiesel (B20) blends under conditions of intermittent use and long-term storage in a relatively hot and dry climate. B20 samples with Rancimat induction periods (IPs) near the current 6.0-hour minimum specification (6.5 hr) and roughly double the ASTM specification (13.5 hr) were prepared from a conventional diesel and a highly unsaturated biodiesel. Four 2011 model year Volkswagen Passats equipped with HPCR fuel injection systems were utilized: one on B0, two on B20-6.5 hr, and one on B20-13.5 hr.
Technical Paper

Catalytic NOx Reduction in Net Oxidizing Exhaust Gas

1990-02-01
900496
Several different possibilities will be described and discussed on the processes of reducing NOx in lean-burn gasoline and diesel engines. In-company studies were conducted on zeolitic catalysts. With lean-burn spark-ignition engines, hydrocarbons in the exhaust gas act as a reducing agent. In stationary conditions at λ = 1.2, NOx conversion rates of approx. 45 % were achieved. With diesel engines, the only promising variant is SCR technology using urea as a reducing agent. The remaining problems are still the low space velocity and the narrow temperature window of the catalyst. The production of reaction products and secondary reactions of urea with other components in the diesel exhaust gas are still unclarified.
Technical Paper

In-Cylinder Measurements and Analysis on Fundamental Cold Start and Warm-up Phenomena of SI Engines

1995-10-01
952394
A recently developed Laser Raman Scattering system was applied to measure the in-cylinder air-fuel ratio and the residual gas content (via the water content) of the charge simultaneously in a firing spark-ignition engine during cold start and warm-up. It is the main objective of this work to elucidate the origin of misfires and the necessity to over-fuel at cool ambient temperatures. It turns out that the overall air-fuel ratio and residual gas content (in particular the residual water content) of the charge appear to be the most important parameters for the occurrence of misfires (without appropriate fuel enrichment), i.e., the engine behaviour from cycle to cycle becomes rather predictable on the basis of these data. An alternative explanation for the necessity to over-fuel is given.
Technical Paper

Quantitative In-Cylinder NO LIF Measurements with a KrF Excimer Laser Applied to a Mass-Production SI Engine Fueled with Isooctane and Regular Gasoline

1997-02-24
970824
Quantitative 1-D spatially-resolved NO LIF measurements in the combustion chamber of a mass-production SI engine with port-fuel injection using a tunable KrF excimer laser are presented. One of the main advantages of this approach is that KrF laser radiation at 248 nm is only slightly absorbed by the in-cylinder gases during engine combustion and therefore it allows measurements at all crank angles. Multispecies detection turned out to be crucial for this approach since it is possible to calculate the in-cylinder temperature from the detected Rayleigh scattering and the simultaneously acquired pressure traces. Additionally, it allows the monitoring of interfering emissions and spectroscopic effects like fluorescence trapping which turned out to take place. Excitation with 248 nm yields LIF emissions at shorter wavelengths than the laser wavelength (at 237 and 226 nm).
Technical Paper

In-Cylinder Mixture Formation Analysis with Spontaneous Raman Scattering Applied to a Mass-Production SI Engine

1997-02-24
970827
Mixture formation analysis in the combustion chamber of a slightly modified mass-production SI engine with port-fuel injection using nonintrusive laser measurement techniques is presented. Laser Raman scattering and planar laser-induced tracer fluorescence are employed to measure air-fuel ratio and residual gas content of the charge with and without spatial resolution. Single-cycle measurements as well as cycle-averaged measurements are performed. Engine operation parameters like load, speed, injection timing, spark timing, coolant temperature, and mean air-fuel ratio are changed to study whether the effects on mixture formation and engine performance can be resolved by the applied laser spectroscopic techniques. Mixture formation is also analyzed by measurement of the charge composition as a function of crank angle. Clear correlations of the charge composition data and engine operating conditions are seen.
Technical Paper

Vapor/Liquid Visualization with Laser-Induced Exciplex Fluorescence in an SI-Engine for Different Fuel Injection Timings

1996-05-01
961122
Laser-induced exciplex fluorescence has been applied to the mixture formation process in the combustion chamber of an optically-accessible four-cylinder in-line spark-ignition engine in order to distinguish between liquid and vapor fuel distribution during the intake and compression stroke for different injection timings. The naphthalene/N,N,N′N′-tetramethyl p-phenylene diamine (TMPD) exciplex system excited at 308nm with a broadband XeCl excimer laser is used to obtain spectrally-separated, single-shot fluorescence images of the liquid or vapor phase of the fuel. For different timings of the fuel injector this technique is applied to obtain crank-angle-resolved images of the resulting mixture in the combustion chamber. The fluorescence light is detected with an intensified slow-scan CCD-camera equipped with appropriate filters.
X