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Technical Paper

The Use of Radioactive Tracer Technology to Measure Real-Time Wear in Engines and Other Mechanical Systems

2007-04-16
2007-01-1437
Radioactive tracer technology (RATT™) is an important tool for measuring real-time wear in operating engines and other mechanical systems. The use of this technology provides important wear information that is not available by other, more conventional wear measurement methods. The technology has advanced to the point where several components can be interrogated simultaneously, and new methods have extended the method to materials that are normally not amenable to radioactive tracer evaluation. In addition, sensitivity has increased so that the onset of wear can be detected long before practical with non-tracer methods. This improves the ability to measure and determine cause and effect relationships, thus providing a better understanding of wear responses to specific operating conditions and to changes in operating conditions. This paper reviews the radioactive tracer process and recent improvements that have extended its reach in both automotive and non-automotive applications.
Technical Paper

Investigation of Alternative Combustion Crossing Stoichiometric Air Fuel Ratio for Clean Diesels

2007-07-23
2007-01-1840
Alternative combustion crossing stoichiometric air fuel ratio was investigated to utilize a 4-way catalyst system with LNT (lean NOx trap). The chemical mechanism of restricting soot formation reactions with low combustion temperature was combined with the physical mechanism of reducing smoke by lowering local equivalence ratio to enable low smoke rich and near rich combustion. A new combustion chamber for spatially and timely mixture formation phasing was developed to combine the two mechanisms and allow smooth EGR changing over a wide load range. Through this investigation, rich and near rich combustion to effectively utilize a 4-way catalyst system was realized. In addition, conditions suitable for LNT sulfur regeneration were realized from light to medium load.
Technical Paper

Engine Crankshaft Position Tracking Algorithms Applicable for Given Arbitrary Cam- and Crank-Shaft Position Signal Patterns

2007-04-16
2007-01-1597
This paper describes algorithms that can recognize and track the engine crankshaft position for arbitrary cam- and crank-shaft tooth wheel patterns in both steady-state and transient operating conditions. Crankshaft position tracking resolution is adjustable to accommodate different application requirements. The instantaneous crankshaft position information provided by the position tracking module form the basis for crankshaft angle domain (CAD) engine control and measurement functions such as precise injection / ignition controls and on-line cylinder pressure CAD analyses. The algorithms described make reconfiguration of the tracking module for different and arbitrary cam- and crank-shaft tooth wheel patterns very easy, which is valuable especially for prototyping engine control systems. The effectiveness of the algorithms is shown using test engines with different cam and crank signal patterns.
Technical Paper

US 2010 Emissions Capable Camless Heavy-Duty On-Highway Natural Gas Engine

2007-07-23
2007-01-1930
The goal of this project was to demonstrate a low emissions, high efficiency heavy-duty on-highway natural gas engine. The emissions targets for this project are to demonstrate US 2010 emissions standards on the 13-mode steady state test. To meet this goal, a chemically correct combustion (stoichiometric) natural gas engine with exhaust gas recirculation (EGR) and a three way catalyst (TWC) was developed. In addition, a Sturman Industries, Inc. camless Hydraulic Valve Actuation (HVA) system was used to improve efficiency. A Volvo 11 liter diesel engine was converted to operate as a stoichiometric natural gas engine. Operating a natural gas engine with stoichiometric combustion allows for the effective use of a TWC, which can simultaneously oxidize hydrocarbons and carbon monoxide and reduce NOx. High conversion efficiencies are possible through proper control of air-fuel ratio.
Technical Paper

Advanced Performance of Metallic Converter Systems Demonstrated on a Production V8 Engine

2002-03-04
2002-01-0347
It has been shown within the catalyst industry that the emission performance with higher cell density technology and therefore with higher specific geometric area is improved. The focus of this study was to compare the overall performance of high cell density catalysts, up to 1600cpsi, using a MY 2001 production vehicle with a 4.7ltr.V8 engine. The substrates were configured to be on the edge of the design capability. The goal was to develop cost optimized systems with similar emission and back pressure performance, which meet physical and production requirements. This paper will present the results of a preliminary computer simulation study and the final emission testing of a production vehicle. For the pre-evaluation a numerical simulation model was used to compare the light-off performance of different substrate designs in the cold start portion of the FTP test cycle.
Technical Paper

A New Approach to Improving Fuel Economy and Performance Prediction through Coupled Thermal Systems Simulation

2002-03-04
2002-01-1208
Vehicle designers make use of vehicle performance programs such as RAPTOR™ to predict the performance of concept vehicles over ranges of industry standard drive cycles. However, the accuracy of such predictions may be greatly influenced by factors requiring more specialist simulation capabilities. For example, fuel economy prediction will be heavily influenced by the performance of the engine cooling system and its impact on the vehicle's aerodynamic drag, and the load from the air-conditioning system. To improve the predictions, specialist simulation capabilities need to be applied to these aspects, and brought together with the vehicle performance calculations through co-simulation. This paper describes the approach used to enable this cosimulation and the benefits achieved by the vehicle designer.
Technical Paper

Effects of High Temperature and Pressure on Fuel Lubricated Wear

2001-09-24
2001-01-3523
While standardized laboratory-scale wear tests are available to predict the lubricity of liquid fuels under ambient conditions, the reality is that many injection systems operate at elevated temperatures where fuel vaporization is too excessive to perform the measure satisfactorily. The present paper describes a High Pressure High Frequency Reciprocating Rig (HPHFRR) purposely designed to evaluate fuel lubricity in a pressurized environment at temperatures of up to 300°C. The remaining test parameters are identical to those of the widely standardized High Frequency Reciprocating Rig (HFRR). Results obtained using the HPHFRR indicate that wear rate with poor lubricity fuels is strongly sensitive to both temperature and oxygen partial pressure and may be orders of magnitude higher than at ambient conditions. Surprisingly however, wear rate was found to decrease dramatically at temperatures above 100°C, possibly due to evaporation of dissolved moisture.
Technical Paper

Development of the Sequence IVA Valve Train Wear Lubricant Test: Part 1

2000-06-19
2000-01-1820
The ASTM Sequence VE test evaluates lubricant performance for controlling sludge deposits and minimizing overhead camshaft lobe wear. ILSAC asked JAMA to develop a new valve train wear replacement test since the Sequence VE test engine hardware will become obsolete in the year 2000. JAMA submitted the JASO specification M 328-951) KA24E valve train wear test. This first report presents the results of technical studies conducted when JASO M 328-95 was reviewed and the ASTM standardized version of the KA24E test (the Sequence IVA) was proposed. The cam wear mechanism was studied with the goal of improving reproducibility and repeatability. Engine torque was specified to stabilize the NOx concentration in blow-by, which improved test precision. Additionally, the specifications for induction air humidity and temperature, oil temperature control, and test fuel composition were modified when the ASTM version of the KA24E test was proposed.
Technical Paper

Study of Modern Application Strategies for Catalytic Aftertreatment Demonstrated on a Production V6 Engine

2001-03-05
2001-01-0925
A study was performed to develop optimum design strategies for a production V6 engine to maximize catalyst performance at minimum pressure loss and at minimum cost. Test results for an advanced system, designed to meet future emission limits on a production V6 vehicle, are presented based on FTP testing. The on-line pressure loss and temperature data serves to explain the functioning of the catalyst.
Technical Paper

Characterization of Particle Size Distribution of a Heavy-Duty Diesel Engine During FTP Transient Cycle Using ELPI

2000-06-19
2000-01-2001
Particle number concentrations and size distributions were measured for the diluted exhaust of a 1991 diesel engine during the US FTP transient cycle for heavy-duty diesel engines. The engine was operated on US 2-D on-highway diesel fuel. The particle measurement system consisted of a full flow dilution tunnel as the primary dilution stage, an air ejector pump as the secondary dilution stage, and an electrical low pressure impactor (ELPI) for particle size distribution measurements. Particle number emission rate was the highest during the Los Angeles Non Freeway (LANF) and the Los Angeles Freeway (LAF) segments of the transient cycle. However, on brake specific number basis the LAF had the lowest emission level. The particle size distribution was monomodal in shape with a mode between 0.084 μm and 0.14 μm. The shape of the size distribution suggested no presence of nanoparticles below the lower detection limit of the instrument (0.032 μm), except during engine idle.
Technical Paper

Intentional Failure of a 5000 psig Hydrogen Cylinder Installed in an SUV Without Standard Required Safety Devices

2007-04-16
2007-01-0431
A vehicle's gasoline fuel tank was removed and replaced with a 5,000-psig, Type-III, aluminum-lined hydrogen cylinder. High-pressure cylinders are typically installed with a thermally-activated pressure relief device (PRD) designed to safely vent the contents of the cylinder in the event of accidental exposure to fire. The objective of this research was to assess the results of a catastrophic failure in the event that a PRD were ineffective. Therefore, no PRD was installed on the vehicle to ensure cylinder failure would occur. The cylinder was pressurized and exposed to a propane bonfire in order to simulate the occurrence of a gasoline pool fire on the underside of the vehicle. Measurements included temperature and carbon monoxide concentration inside the passenger compartment of the vehicle to evaluate tenability. Measurements on the exterior of the vehicle included blast wave pressures. Documentation included standard, infrared, and high-speed video.
Technical Paper

On-Board Fuel Property Classifier for Fuel Property Adaptive Engine Control System

2006-04-03
2006-01-0054
This paper explores the possibility of on-board fuel classification for fuel property adaptive compression-ignition engine control system. The fuel classifier is designed to on-board classify the fuel that a diesel engine is running, including alternative and renewable fuels such as bio-diesel. Based on this classification, the key fuel properties are provided to the engine control system for optimal control of in-cylinder combustion and exhaust treatment system management with respect to the fuel. The fuel classifier employs engine input-output response characteristics measured from standard engine sensors to classify the fuel. For proof-of-concept purposes, engine input-output responses were measured for three different fuels at three different engine operating conditions. Two neural-network-based fuel classifiers were developed for different classification scenarios. Of the three engine operating conditions tested, two conditions were selected for the fuel classifier to be active.
Technical Paper

The Use of Radioactive Tracer Technology to Evaluate Engine Wear Under the Influences of Advanced Combustion System Operation and Lubricant Performance

2005-10-24
2005-01-3689
Radioactive tracer technology is an important tool for measuring component wear on a real-time basis and is especially useful in measuring engine wear as it is affected by combustion system operation and lubricant performance. Combustion system operation including the use of early and/or late fuel injection and EGR for emissions control can have a profound effect on aftertreatment contamination and engine reliability due to wear. Liner wear caused by localized fuel impingement can lead to excessive oil consumption and fuel dilution can cause excessive wear of rings and bearings. To facilitate typical wear measurement, the engine's compression rings and connecting rod bearings are initially exposed to thermal neutrons in a nuclear reactor to produce artificial radioisotopes that are separately characteristic of the ring and bearing wear surfaces.
Technical Paper

Ignition of Underbody and Engine Compartment Hydrogen Releases

2006-04-03
2006-01-0127
Various fire scenarios involving a hydrogen fuel system were simulated to evaluate their associated safety hazards. Scenarios included finite releases of hydrogen with delayed ignition as well as small hydrogen jet-fire releases. The scenarios tested resulted in minimal damage to the vehicle, minimal hazards to the vehicle's surroundings, and no observable damage or hazards within the passenger compartment.
Technical Paper

A History of Mack Engine Lubricant Tests from 1985-2005: Mack T-7 through Mack T-12

2005-10-24
2005-01-3713
As on-highway, heavy-duty diesel engine designs have evolved to meet tighter emissions specifications and greater customer requirements, the crankcase environment for heavy-duty engine lubricants has changed. Engine lubricant quality is very important to help ensure engine durability, engine performance, and reduce maintenance downtime. Beginning in the late 1980's, a new Mack genuine oil specification and a new American Petroleum Institute (API) heavy-duty engine lubricant category have been introduced with each new U.S. heavy-duty, on-highway emissions specification. This paper documents the history and development of the Mack T-7, T-8, T-8A, T-8E, T-9, T-10, T-11, and T-12 engine lubricant tests.
Technical Paper

Laser Ignition in a Pre-Mixed Engine: The Effect of Focal Volume and Energy Density on Stability and the Lean Operating Limit

2005-10-24
2005-01-3752
A series of tests using an open beam laser ignition system in an engine run on pre-mixed, gaseous fuels were performed. The ignition system for the engine was a 1064 nm Nd:YAG laser. A single cylinder research engine was run on pre-mixed iso-butane and propane to determine the lean limit of the engine using laser ignition. In addition, the effect of varying the energy density of the ignition kernel was investigated by changing the focal volume and by varying laser energy. The results indicate that for a fixed focal volume, there is a threshold beyond which increasing the energy density [kJ/m3] yields little or no benefit. In contrast, increasing the energy density by reducing the focal volume size decreases lean performance once the focal volume is reduced past a certain point. The effect of ignition location relative to different surfaces in the engine was also investigated. The results show a slight bias in favor of igniting closer to a surface with low thermal conductivity.
Technical Paper

Electrification and Integration of Accessories on a Class-8 Tractor

2005-04-11
2005-01-0016
This paper describes installation and testing of electrified engine accessories and fuel cell auxiliary power units for a Class-8 tractor. A 2.4 kW fuel cell APU (Auxiliary Power Unit) has been added to supply a 42 V power supply for electrification of air conditioning and water pump systems. A 42/12 V dual alternator was used to replace the OEM alternator to provide safety back-up in case of fuel cell failure. A QNX Real Time Operating System-based (RTOS) Rapid Prototype Electronic Control System (RPECS™), developed by Southwest Research Institute (SwRI™), is used for supervisory control and coordination between accessories and engine. A Controller Area Network (CAN) interface, from the engine Electronic Control Unit (ECU), and the RS232 interface, from the fuel cell controllers, provide system data and control for RPECS. Custom wiring to the hydrogen, water pump, and air conditioning systems also provide data to RPECS. The water pump system controller is autonomous.
Technical Paper

Virtual Cylinder Pressure Sensor (VCPS) with Individual Variable-Oriented Independent Estimators

2005-04-11
2005-01-0059
Tremendous amount of useful information can be extracted from the cylinder pressure signal for engine combustion control. However, the physical cylinder pressure sensors are undesirably expensive and their health need to be monitored for fault diagnostic purpose as well. This paper presents the results of the development of a virtual cylinder pressure sensor (VCPS) with individual variable-oriented independent estimators. Two neural network-based independent cylinder pressure related variable estimators were developed and verified at steady state. The results show that these models can predict the variables correctly compared with the extracted variables from the measured physical cylinder pressure sensor signal. Good generalization capabilities of the developed models are observed in the sense that the models work well not only for the training data set but also for the new inputs that they have never been exposed to before.
Technical Paper

Experimental Investigation of the Scavenging Performance of a Two-Stroke Opposed-Piston Diesel Tank Engine

2004-03-08
2004-01-1591
The Tank-Automotive RD&E Center periodically conducts foreign materiel evaluations to assess the current state of the art for ground vehicle technologies. The Propulsion Laboratory is conducting performance evaluations of an opposed-piston two-stroke diesel tank engine produced by the Kharkov Design Bureau in Ukraine. A key factor in the performance of all two-stroke engines is the scavenging process, which determines how well the cylinders are emptied of exhaust and filled with fresh air. The overall air flow rate is not sufficient to determine this, as a significant amount of air may be lost through the exhaust ports during the scavenging process. The inlet tracer gas method was employed to provide the additional data required. With methane as the tracer, it produced reasonable and consistent data over a wide range of engine speeds and loads. The inlet tracer gas method was found to be an effective tool for measuring the scavenging performance of a running two-stroke diesel engine.
Technical Paper

Parasitic Loss Reduction for 21st Century Trucks

2000-12-04
2000-01-3423
To reach its objective of reducing vehicle fuel consumption by 50 percent, the development of the 21st Century Truck (21T) will address all the aspects of truck design contributing to the achievement of that goal. [1] This paper will address one of these aspects, specifically vehicle parasitic loss reduction with special emphasis on drive train losses, concentrating on the potential benefits of replacing mechanical coolant (water) and oil pumps with electrically powered pumps.
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