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Technical Paper

A Procedure for Evaluating Cycle Emissions from Raw Exhaust Gas Analyses

1988-03-01
871194
A procedure has been developed for evaluating equivalent drive cycle emission results from raw exhaust gas emissions data obtained from an engine under test on a computer controlled Vehicle Simulator Engine Dynamometer. The emitted species data is integrated with the air intake flow rate to determine the total mass of emissions, after correcting for the reduction in exhaust gas mass due to precipitation of the moisture of combustion. This procedure eliminates the need for the Constant Volume Sample (CVS) System attached to the vehicle exhaust while undergoing simulated drive testing on a chassis dynamometer to evaluate compliance of the test vehicle with the Australian Design Rules, ADR27 and ADR37. Sources of error with the procedure are examined by comparing the fuel consumption measured using a volumetric technique during the test with that evaluated by a carbon balance procedure as given in the Australian Design Rules.
Technical Paper

Contribution of Soot Contaminated Oils to Wear-Part II

1999-05-03
1999-01-1519
Diesel soot interacts with the engine oil and leads to wear of engine parts. Engine oil additives play a crucial role in preventing wear by forming the anti-wear film between the wearing surfaces. The current study was aimed at investigating the interactions between engine soot and oil properties in order to develop high performance oils for diesel engines equipped with exhaust gas re-circulation (EGR). The effect of soot contaminated oil on wear of engine components was examined using a statistically designed experiment. To quantitatively analyze and simulate the extent of wear a three-body wear machine was designed and developed. The qualitative wear analysis was performed by examining the wear scars on an AISI 52100 stainless steel ball worn in the presence of oil test samples on a ball-on-flat disc setup. The three oil properties studied were base stock, dispersant level and zinc dithiophosphate level.
Technical Paper

A Study on the Practicability of a Secondary Air Injection for Emission Reduction

1999-05-03
1999-01-1540
In this study, feasibility tests of secondary air injection technology and lean A/F control technology were performed for LEV program using the FTP75 test on a 2.0 DOHC A/T vehicle. Second-by-second emissions and temperatures were evaluated. The temperatures of exhaust gas were measured at exhaust manifold, front of warm up, and the center of warm up converter. At first, amount of secondary air injection was determined with a bench aged warm up converter and a fresh UCC. And then, the performances of secondary air injection and lean A/F control strategy were compared with 80,000km vehicle aged converters(warm up converter, UCC). Both secondary air injection and lean A/F control technologies satisfied the ULEV regulation. This study shows that the lean A/F control strategy can be one of the potential technologies to meet the LEV/ULEV regulations without an active system that need a cost up.
Technical Paper

A Method to Measure Air Conditioning Refrigerant Contributions to Vehicle Evaporative Emissions (SHED Test)

1999-05-03
1999-01-1539
Although the intent of the SHED test (Sealed Housing for Evaporative Determination) is to measure evaporative fuel losses, the SHED sampling methodology in fact measures hydrocarbons from all vehicle and test equipment sources. Leakage of air conditioning (AC) refrigerant is one possible non-fuel source contributing to the SHED hydrocarbon measurement. This report describes a quick and relatively simple method to identify the contribution of AC refrigerant to the SHED analyzer reading. R134A (CH2FCF3), the hydrofluorocarbon refrigerant used in all current automotive AC systems, as well as its predecessor, the chlorofluorocarbon R12, can be detected using the gas chromatography methods currently in place at many emissions labs for the speciation of exhaust and evaporative hydrocarbon emissions.
Technical Paper

Heating Aircraft Reciprocating Engines

1999-04-20
1999-01-1568
Aircraft engines need preheating to be able to start without damage in cold weather. It is possible to do this efficiently by placing a small amount of heat in the proper places. An installed electric system is very convenient and easy to use. A good design will be light weight and energy efficient. Corrosion in engines that operate in cold weather can be reduced or eliminated by the right preheater design and the proper operation of the engine. Some designs of preheater systems aggravate other problems. A certain amount of caution is needed in selecting the system. The unit should be specifically matched to the aircraft and engine.
Technical Paper

Basic Understanding of Activated Radical Combustion and Its Two-Stroke Engine Application and Benefits

2000-06-19
2000-01-1836
For a better understanding of the auto-ignition phenomenon in internal combustion engines, consideration is given from the in-cylinder gas temperature aspect. Experimental results demonstrate that the in-cylinder gas temperature at the end of compression, namely, the “auto-ignition temperature” is deeply involved in the onset of auto-ignition. The relation between the gas exchange state and the auto-ignition temperature explains the mechanism of timing controlled auto-ignition, namely, Activated Radical (AR) Combustion. The auto-ignition temperature is maintained constant during the AR combustion state, thanks to the exhaust valve controlling the hot residual gas amount. Finally, the utilization of auto-ignition in gasoline engines is discussed from the methodology aspect.
Technical Paper

A Compact and Robust Corona Discharge Device (CDD™) for Generating Non-Thermal Plasma in Automotive Exhaust

2000-06-19
2000-01-1845
We describe the details of a particular compact and robust Corona Discharge Device (CDD™) that generates non-thermal plasma in the harsh environment of a stoichiometric exhaust. This particular CDD™ can generate plasma power of up to 15W at exhaust gas temperatures to 850C. Optimizations of geometry, material selection, and thermal design were performed by a combination of simulation and experiment. This particular design considered tradeoffs of several factors, including plasma power, EMI shielding, thermal durability, high voltage interconnection, packaging size, and exhaust emissions reduction. This particular CDD™ was designed to meet most of the same durability and survivability specifications as an O2 sensor, since both are exposed to similar exhaust environments.
Technical Paper

The SMAC, Under Pressure Oil Aeration Measurement System in Running Engines

2000-06-19
2000-01-1818
Gas entrainment in engine oil circuit generates many problems. This is especially true for hydraulic tappets. A new oil gas content measurement apparatus, the SMAC, has been developed by IFP and D2T. It is able to measure the volumetric gas to oil ratio at any point of the engine oil circuit while running, without influencing the pressure or temperature of the oil. Some engine tests have been conducted with PSA. First results show that a steady gas content is achieved only slowly. Gas content is very sensitive to engine speed and oil temperature (i.e. running point effect). Gas content is very different from one location to another in the oil circuit (i.e. architecture effect). Oil formulation also influences gas content (i.e. oil effect) and the SMAC method does not rank the oils in the same way as the ASTM methods.
Technical Paper

Effect of Injection Parameters on Diesel Spray Characteristics

2000-04-02
2000-01-1600
This paper reports efforts to study the effect of various injection parameters on macro characteristics of diesel sprays generated by a state-of-the-art common-rail injection system. The main purpose is to validate and extend various correlations available in the literature to the case of sprays generated by common-rail injection systems which are characterized by high injection pressures and small orifice diameters. Experiments were conducted by spraying into a quiescent atmosphere at room temperature. Densities close to in-cylinder conditions at the start of injection were established using pressurized nitrogen. While the measured macro characteristics - spray penetration length and spray cone angle - agreed well with established correlations, distinct deviations could be observed. Possible explanations for such deviations are discussed.
Technical Paper

Non-Thermal Plasma System Development for CIDI Exhaust Aftertreatment

2000-04-02
2000-01-1601
There is a need for an efficient, durable technology to reduce NOx emissions from oxidative exhaust streams such as those produced by compression-ignition, direct-injection (CIDI) diesel or lean-burn gasoline engines. A partnership formed between the DOE Office of Advanced Automotive Technology, Pacific Northwest National Laboratory, Oak Ridge National Laboratory and the USCAR Low Emission Technologies Research and Development Partnership is evaluating the effectiveness of a non-thermal plasma in conjunction with catalytic materials to mediate NOx and particulate emissions from diesel fueled light duty (CIDI) engines. Preliminary studies showed that plasma-catalyst systems could reduce up to 70% of NOx emissions at an equivalent cost of 3.5% of the input fuel in simulated diesel exhaust. These studies also showed that the type and concentration of hydrocarbon play a key role in both the plasma gas phase chemistry and the catalyst surface chemistry.
Technical Paper

A Laboratory Study of NOX Reduction During the Rich Operating Period Over a NOX Storage Catalyst

1999-10-25
1999-01-3502
The behaviour of a NOx storage catalyst in powdered form and containing a storage component based on alkaline metal was investigated under rich conditions. Experiments were conducted in a fixed-bed flow reactor with the space velocity set at 45,000 h-1. From these experiments it was possible to extract the fractional NOx reduction and the efficiency of use of the reductant. With 0.9% CO as a reductant at 350°C, complete utilisation of CO was achieved up to 70% NOx conversion as treatment time was increased. To obtain 90% NOx conversion required longer times, and 23% of the CO did not participate in the reduction of NOX. A reductant balance shows that about 40% of the CO added is used to reduce the catalyst surface when the flow is switched from lean to rich. The ranking of efficiencies of different reductant gases at 350°C gave the following sequence: 0.9% H2 ≈ 0.9% CO > 1285 ppm toluene > 3000 ppm propene ≈ 1125 ppm i-octane > 3000 ppm propane.
Technical Paper

ATAC and GDI in a Small Two-Stroke Engine

1999-09-28
1999-01-3273
In two-stroke S.I. engines, direct fuel injection prevents fuel short-circuiting from the exhaust port, however it does not solve per se combustion problems at light loads due to excessive ratio of residual-to-fresh gas. These problems can be solved by ATAC (Active Thermo Atmosphere Combustion), since residual-gas thermal energy is used to prime the combustion of fresh gas. Experimental results of a small two-stroke S.I. engine with medium-pressure air-assisted fuel injection, operating on ATAC at light loads are shown and prove the possibility to combine the two solutions.
Technical Paper

Experimental and Theoretical Investigations of Removal of NOx from Diesel-Type Engine Exhaust Using Dielectric Barrier Discharges

1999-10-25
1999-01-3686
Removing toxic impurities from gaseous flows by electrical gas discharges has been investigated for almost two decades. Cold discharges, i.e. plasmas in which the electrons are not in thermal equilibrium with neutrals and ions, are a potential method for the conversion of NOx (NO, NO2) and hydrocarbons (HC) in exhaust gases of cars. In this work we present experimental results of removing nitric oxides in synthetic and real diesel exhaust and compare these results with modelling results using a spatially homogeneous, time-dependent model. We also compare results obtained by a two-dimensional, time-dependent model with experimental data measured with the LIF-method to test the accuracy of our numerical simulation results for the discharge behaviour.
Technical Paper

Recent Performance Testing of the TecoJet Post-Combustion DeNOx Technology for Diesel Engines

1999-10-25
1999-01-3684
Research in the application of nonthermal plasma technology to remove NOx from combustion flue gas is dominated by the oxidation of NO to NO2 and HNO3 (nitric acid), undesirable end products for mobile engine applications. An alternative approach is to react the NO with atomic nitrogen injected into the gas stream to reduce the NO into nitrogen and oxygen. The atomic nitrogen is generated by flowing nitrogen through multiple electrically excited, high-speed jet nozzles. The technology functions well in the sooty and wet conditions characteristic of diesel engines. A prototype system has been built and successfully demonstrated on a diesel engine exhaust slipstream at Caterpillar Inc.
Technical Paper

The Development of the Ceramic Gas Engine Co-Generation System

1999-10-25
1999-01-3667
The Japan Gas Association has been engaged in the development of a 200-kW-class ceramic natural gas engine system to be used as a co-generation power source, subsidized by Ministry of International Trade and Industry. The engine has several new concepts to achieve high efficiency and low emissions simultaneously and to enable to use natural gas as fuel supplied with low pressure in spite of diesel engine. The co-generation system needs de-NOx system. So, we developed a urea de-NOx catalyst system for high-temperature exhaust gas. This paper will describe the result in the fiscal year 1998.
Technical Paper

Comparison of Different Ways for Image Post-Processing: Detection of Flame Fronts

1999-10-25
1999-01-3651
A detailed understanding of the complex chemistry-turbulence interaction is gaining an increasing importance for further improvement of IC engine performance. Multidimensional optical diagnostic techniques have become a versatile tool for engine development. Sophisticated automatic data post-processing will achieve an increasing significance for efficient data reduction in such optical experiments. The focus of this paper is the detection of flame fronts using different image processing algorithms. In a further step of the data reduction, the extraction of the length of the flame front and the area of the burnt gases is presented. A strategy relying on a sensitivity analysis is discussed which allows an objective choice of parameters necessary for the application of the mathematical algorithms.
Technical Paper

Optical Studies in a DI Diesel Engine

1999-10-25
1999-01-3650
Fuel injection and combustion was studied with direct photography in a single cylinder DI diesel engine. Optical access was accomplished by using an endoscope-based measurement system. In the optical measurements the influence of several parameters were studied: start of injection, inlet air temperature and pressure, injected fuel amount (constant air mass), load level (varying air and fuel mass) and nozzle hole diameter. Liquid fuel spray penetration, flame lift-off and flame length were measured. The maximum spray penetration was 23 - 25 mm. As diffusion combustion started, the spray length decreased to about 15 mm. The flame lift-off was located 4 - 6 mm behind the liquid fuel spray tip. Using the two-color method the spatial temperature distribution in flames was calculated.
Technical Paper

Fouling Prevention Using Plasma Catalysis

1999-10-25
1999-01-3641
Atmospheric pressure nonthermal plasmas packed with a catalyst are applied to decomposition of toxic and hazardous materials in flowing gas streams for building heating, ventilation, and air conditioning (HVAC) systems. We have conducted several experiments wherein the gas phase corona reactor (GPCR) process avoids catalyst-poisoning problems. Cyanogen chloride was passed through a GPCR and a thermal reactor packed with the same three-way automobile catalyst operated at similar conditions including temperature, catalyst volume, and contaminant challenges. Within two hours, the typical breakthrough curve was observed. Large amounts of cyanogen chloride were soon found in the thermal catalyst reactor effluent revealing poisoning. In contrast, the GPCR was operated for over 100 hours without poisoning the catalyst. Other experiments are described.
Technical Paper

Electrical Characterization of a Dielectric Barrier Discharge Plasma Device

1999-10-25
1999-01-3635
A planar dielectric barrier discharge device has been tested for exhaust emission reduction in simulated engine exhaust. This device's electrical characteristics have been measured and are presented in this paper. The device consists of two dielectric barriers which act like series capacitors, with the gas gap between them. At low gap voltages, the gas gap also acts like a capacitance, with a much smaller capacitance than the barriers. At higher voltages, the gas gap breaks down and a blue–purple glow visually fills the gap. The partially ionized gas conducts charge across the gap, building electrical charge on the dielectric barrier inner surface. When the AC excitation voltage peaks and starts to go toward an opposite polarity, the discharge momentarily extinguishes, trapping charge in the dielectric barrier capacitance.
Technical Paper

Exhaust Emission Reduction of Combustion Engines by Barrier Discharge - A new Reactor/Generator System

1999-10-25
1999-01-3638
An improved plasma reactor has been designed, built and evaluated. It is characterized by a reduced power per area ratio, relative to previous designs, and includes several improvements to run the whole system safely in a car. The new reactor design includes a concentric inner high voltage electrode, a grounded outer electrode, a shielded high-voltage and high temperature resistant electrical connection. A generator controller has been developed for better control of operating conditions as required during the engine cold start phase. The new generator/reactor system was installed in the exhaust pipe of a gasoline direct injection engine. HC emissions could be reduced up to 30 % in the first 40 seconds of a cold start test. In addition to HC treatment the dielectric barrier discharge has also been investigated as a method for regenerating a diesel particulate trap.
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