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Acoustic standing waves are excited in internal combustion chambers by both normal combustion and autoignition. The energy in these acoustic modes can be transmitted through the engine block and radiated as high-frequency engine noise. Using finite-element models of two different (four-valve and two-valve) production engine combustion chambers, the mode shapes and relative frequencies of the in-cylinder volume acoustic modes are calculated as a function of crank angle. The model is validated by comparison to spectrograms of experimental time-sampled waveforms (from flush-mounted cylinder pressure sensors and accelerometers) from these two typical production spark-ignited engines.

Until a proper fueling infrastructure is established, vehicles powered by natural gas must have bi-fuel capability in order to avoid a limited vehicle range. Although bi-fuel conversions of existing gasoline engines have existed for a number of years, these engines do not fully exploit the combustion and knock properties of both fuels. Much of the power loss resulting from operation of an existing gasoline engine on compressed natural gas (CNG) can be recovered by increasing the compression ratio, thereby exploiting the high knock resistance of natural gas. However, gasoline operation at elevated compression ratios results in severe engine knock. The use of variable intake valve timing in conjunction with ignition timing modulation and electronically controlled exhaust gas recirculation (EGR) was investigated as a means of controlling knock when operating a bi-fuel engine on gasoline at elevated compression ratios.

The objective of this study is to improve fuel economy and reduce carbon dioxide emissions in diesel-electric hybrid automotive powertrains by developing an exhaust gas turbine generator system which utilizes exhaust gas energy from the turbocharger waste gate. The design of the exhaust gas turbine generator was based on a conventional turbocharger for a direct-injection diesel engine. Data from steady-state bench tests using air indicates about 50% of the turbine input energy can be converted to electric energy. Turbine generator output averaged 3 kW, while a maximum of about 6 kW was observed. Based on this data, we estimate that energy consumption in a vehicle could be reduced between 5% and 10%. Engine tests were conducted under both steady-state and transient conditions. These tests revealed that optimal performance occurred under high-speed, high-load conditions, typical of highway or uphill driving, and that performance at low-speed, low-loads was relatively poor.

THE INFLUENCE OF INLET MANIFOLD DESIGN on knock in a naturally aspirated single-cylinder S-I engine under wide-open-throttle operating conditions has been investigated by carrying out computer simulations and engine tests. The different inlet manifold configurations were compared at engine speeds where they had equal volumetric efficiency. COMPUTER SIMULATIONS showed that when the mass flow into the cylinder is enhanced during the early part of the intake stroke, there is less tumble and lower in-cylinder temperature after compression. The reason for the lower temperature is that the heat transfer from the cylinder walls to the charge is reduced when tumble is decreased. The lower temperature of the charge should have a positive effect in reducing knock. ENGINE TESTS were carried out on a single-cylinder research engine. Different inlet manifold lengths and diameters were tested. All other parameters were kept constant.

The experimental emissions testing of a turbocharged six cylinder Caterpillar 3116 diesel engine converted to the Miller cycle operation was conducted. Delayed intake valve closing times were also investigated. Effects of intake valve closing time, injection time, and insulation of piston, head, and liner on the emission characteristics of the Miller cycle engine were experimentally verified. Superior performance and emission characteristic was achieved with a LHR insulated engine. Therefore, all emission and performance comparisons are made with LHR insulated standard engine with LHR insulated Miller cycle engine. Particularly, NOx, CO2, HC, smoke and BSFC data are obtained for comparison. Effect of increasing the intake boost pressure on emission was also studied. Poor emission characteristics of the Miller cycle engine are shown to improve with increased boost pressure. Performance of the insulated Miller cycle engine shows improvement in BSFC when compared to the base engine.

An algorithm for a fuel efficient hybrid drivetrain control system that can attain fewer exhaust emissions and higher fuel economy was investigated. The system integrates a lean burn engine with high supercharging, an exhaust gas recycle system, an electric machine for power assist, and an electronically controlled gear transmission. Smooth switching of the power source, the air-fuel ratio,pressure ratio, exhaust gas ratio as a function of the target torque were analyzed. The estimation of air mass in cylinder by using an air flow meter was investegated to control the air-fuel ratio precisely during transients.

A naturally-aspirated, Miller cycle, Spark-Ignition (SI) engine that controls output with variable intake valve closure is compared to a conventionally-throttled engine using computer simulation. Based on First and Second Law analyses, the two load control strategies are compared in detail through one thermodynamic cycle at light load conditions and over a wide range of loads at 2000 rpm. The Miller Cycle engine can use late intake valve closure (LIVC) to control indicated output down to 35% of the maximum, but requires supplemental throttling at lighter loads. The First Law analysis shows that the Miller cycle increases indicated thermal efficiency at light loads by as much as 6.3%, primarily due to reductions in pumping and compression work while heat transfer losses are comparable.

The manufacturing of modern engines requires an optimization down to component level. Near net shape connecting rods with high fatigue strength are opening a range to reduce costs and improve the engine's performance. In the last years the development of production technology for steel-forged rough parts was continued aiming at a reduction of the required machining steps. Simultaneously the benefit of high fatigue strength for the forged steel compared to alternative powder metal material can be maintained.

Presented in this paper is a description of an automobile that is partially retrofitted with a hybrid HID/fiber focus-less optic system. Tail lights are constructed that provide stops, turns, CHMSL, and backups. Lenses are used to meet the most demanding beam patterns. Focus-less optics (FLO) are used with waveguides to collect the rest of the light off the HID and to distribute to the rest of the car. Preliminary measurements indicate that the tail light beam patterns are legal according to SAE and DOT specifications. Different features discussed include electro mechanical modulators (EMM), liquid crystal device modulators (LCD).

This paper describes a recently developed sensor, the High-Performance Flowmeter (HPF), which measures flow rates in raw, undiluted exhaust. The HPF is based on the principle of acceleration or deceleration of an ultrasonic pulse due to a flow of gas. It allows a two-directional detection of flow with high accuracy and high sampling rates. Formerly, all flow sensors were limited to low temperatures and low sampling rates when measuring the flow rates directly in raw exhaust. An entirely new principle has been developed for this generation of ultrasonic pulses which improves the performance of ultrasonic flow sensors dramatically. Using this principle, such flow sensors can be used for the first time to measure dynamic flow rates in raw exhaust at high temperatures with sampling rates up to several hundred hertz.

This work attempts a systematic investigation of the effects of flow maldistribution on the light-off behavior of a monolithic catalytic converter. To achieve this goal, a combined chemical reaction model and three-dimensional computational fluid dynamic modeling technique has been developed. The computational results reveal that the influence of area ratio was significant during high flow transient conditions. The cross-sectional area ratio with the smaller value increases the thermal gradient due to flow maldistribution in the monolith, which degrades performance of catalytic converter. Due to locally concentrated high velocities, large portions of the monolith remain cold and CO,HC are unconverted during warm up period. Therefore, flow maldistribution can cause a significant retardation of the light-off and can eventually worsen the conversion efficiency.

A technique has been developed for producing Light Fibers with Precision Lighting Elements, which emit side light in carefully controlled patterns for exterior lighting applications. Target specifications can now be satisfied with light delivered from a very small, robust package. Conventional lenses and reflectors are not required. Three exterior applications have been targeted: the Center High Mounted Stop Lamp (CHMSL), a Side Marker, and an Emergency Flasher. An optical model of each application has been built, for which basic input parameters are target distribution, fiber diameter, and fiber length. Fiber cores are manufactured with the desired optical elements; cladding and a reflective coating over the notches complete the Precision Lighting Element. Measured intensity distributions from prototypes meet the modeled performance expectations.

The critical particle size for a high-pressure injection system was determined. Various double-cut test dusts ranging from 0 to 5 μm to 10 to 20 μm were evaluated to determine which test dust caused the high-pressure system to fail. With the exception of the 0- to 5-μm test dust, all test dust ranges caused failure in the high-pressure injection system. Analysis of these evaluations revealed that the critical particle size, in initiating significant abrasive wear, is 6 to 7 μm. Wear curve formulas were generated for each evaluation. A formula was derived that allows the user to determine if the fuel filter effluent will cause harmful damage to the fuel system based on the number of 5-, 10-, and 15-μm particles per milliliter present. A methodology was developed to evaluate fuel filter performance as related to engine operating conditions. The abrasive methodology can evaluate online filter efficiency and associated wear in a high-pressure injection system.

The measure of a successful air filter seal is its ability to seal at installation, and reseal after routine inspection, without exerting excessive force on the air cleaner housing. Filter seal evaluation requires selection of a test sample to measure, a property to measure, and a measuring method. Test samples include complete filter seals, portions of a filter seal, slab samples of various shapes, and free-rise cup samples. Properties include compression set and resistance to compression. Measuring methods include clamping samples between plates, durometer readings, and in-housing compression tests. The merits of each test sample, property, and measuring method will be discussed with regard to microcellular polyurethane foam seals.

This paper presents results from a series of tests that address safety related issues concerning vehicle glazing. These issues include occupant containment, head impact injury, neck injuries, fracture modes, and laceration. Component-level and full vehicle crash tests of standard and polycarbonate non-windshield glazing were conducted. The tests were conducted as part of a study to demonstrate that there is no decrease in the safety benefits offered by polycarbonate glazing when compared to current glazing. Readers of this paper will gain a broader understanding of the tests that are typically conducted for glazing evaluation from a safety perspective, as well as gain insight into the meaning of the results.

A model is presented in which distinction is made between the contributions of the different mechanisms of heat transfer to an air bag fabric during deployment. An experimental setup, designed for simulation and recording of the thermal response of permeable and coated (impermeable) air bag fabrics, is described. Comparisons between the experimental results and numerical predictions show fair agreement. The preliminary results show that the model provides a framework in which the interplay between the three convective heat transfer coefficients (two surface and one volumetric) that affect the fabric temperature (and the heat loss from the upstream bag gas) can be examined. Currently the magnitude of these surface convective heat fluxes are being examined experimentally.

Conventional panel air filter performance is limited by packaging size constraints. The purpose of this paper is to introduce the stacked panel air filter design concept for use in automotive air intake systems. This unique filter utilizes conventional panel air filter design concepts to provide dual filtration and increased filtration performance. Filter design and performance test results are presented, discussed and compared.

Emission of carbon dioxide from mobile sources is receiving interest as part of a coordinated approach to limit greenhouse gases. Coupled with the relatively high price of gasoline in some countries this has resulted in the development of lean burn and direct injection gasoline engines. These engines will require conversion of nitrogen oxides (NOx) in excess of 70% in a net oxygen rich exhaust stream to meet future emission limits. This paper describes recent advances in the performance of NOx trap technology in terms of adsorption capacity, temperature of operation and thermal durability. The application of a new NOx trap together with a newly developed starter catalyst, to a direct injection gasoline vehicle shows that European stage IV limits can be reached for NOx and CO with a fresh system.

NOx storage-reduction catalysts have shown serious deactivation in the presence of SOx. This is because, under lean conditions, SOx adsorbs more strongly on NO2 adsorption sites than NO2, and the adsorbed SOx does not desorb altogether even under rich conditions. We have solved the problem by configuring, in front of the NOx storage-reduction catalysts, SOx adsorbents that can adsorb only SOx among SOx and NOx in exhaust gases under the lean conditions and desorb the adsorbed SOx easily under the rich conditions. The catalysts can reduce NOx, CO and hydrocarbons at a high rate for a prolonged period.

Powertrain simulation is becoming an increasingly valuable tool to evaluate new technologies proposed for future military vehicles. The powertrain of the M1A1 Abrams tank is currently being modeled in the Powertrain Control Research Laboratory (PCRL) at the University of Wisconsin-Madison. This powertrain model is to be integrated with other component models in an effort to produce a high fidelity simulation of the entire vehicle.