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The fierce competition and shifting consumer demands require automotive companies to be more efficient in all aspects of vehicle development and specifically in the area of embedded engine control system development. In order to reduce development cost, shorten time-to-market, and meet more stringent emission regulations without sacrificing quality, the increasingly complex control algorithms must be transportable and reusable. Within an efficient development process it is necessary that the algorithms can be seamlessly moved throughout different development stages and that they can be easily reused for different applications. In this paper, we propose a flexible engine control architecture that greatly boosts development efficiency.

Modeling tailpipe NOx emissions has always been difficult due to the complexity of the numerous factors involved in the catalytic conversion of the pollutant. Most emissions modeling has been based on steady state driving. A parameterized algebraic model for second-by-second tailpipe emissions of NOx for a composite Tier 1 car is presented employing data from the Federal Test Procedure Revision Project (FTPRP). Calculating fuel rate from measured engine out values, the catalytic converter is physically modeled based on the fuel rate history and a few fitted parameters. Under certain conditions, the changes in fuel rate are related to trends in the air to fuel ratio. The model accurately predicts the time dependence of hot stabilized tailpipe NOx emissions in the FTP bag 3 and US06 driving cycles. Modeling of low power driving, as in bag 2, is not as successful.

An aftertreatment system involving a LNT followed by a SCR catalyst is proposed for treating the NOx emissions from a diesel engine. NH3 (or urea) is injected between the LNT and the SCR. The SCR is used exclusively below 400°C due to its high NOx activity at low temperatures and due to its ability to store and release NH3 below 400°C, which helps to minimize NH3 and NOx slip. Above 400°C, where the NH3 storage capacity of the SCR falls to low levels, the LNT is used to store the NOx. A potassium-based LNT is utilized due to its high temperature NOx storage capability. Periodically, hydrocarbons are oxidized on the LNT under net lean conditions to promote the thermal release of the NOx. NH3 is injected simultaneously to reduce the released NOx over the SCR. The majority of the hydrocarbons are oxidized on the front portion of the LNT, resulting in the rapid release of stored NOx from that portion of the LNT.

This paper describes the design and functionality of an in-situ air entrainment measuring device for analysis of the air entrainment and air release properties of lubricating fluids. The apparatus allows for a variety of measurement techniques for the aeration and deaeration of the lubricating fluid at various temperatures, pressures, and agitation speeds. This test apparatus is patent pending because of its unique ability to allow for continuous, in-situ measurement of the fluid properties and the rates of change of these properties. Most other measurement techniques and apparatuses do not allow for uninterrupted measurement. This apparatus is also unique in that it is capable of detecting minor fluid density changes at a lower level and with more accuracy than all other current techniques or apparatuses.

Quantification of residual stresses is an important engineering problem impacting manufacturabilty and durability of metallic components. An area of particular concern is residual stresses that can develop during heat treatment of metallic components. Many heat treatments, especially in heat treatable cast aluminum alloys, involve a water-quenching step immediately after a solution-treatment cycle. This rapid water quench has the potential to induce high residual stresses in regions of the castings that experience large thermal gradients. These stresses may be partially relaxed during the aging portion of the heat treatment. The goal of this research was to develop a test sample and quench technique to quantify the stresses created by steep thermal gradients during rapid quenching of cast aluminum. The development and relaxation of residual stresses during the aging cycle was studied experimentally with the use of strain gauges.

The super-ultra-low-emission-vehicle (SULEV) non-methane organic gas (NMOG) hydrocarbon exhaust standard as legislated by the state of California LEV II regulations is 10 milligrams per mile. This requires that the associative instrumentation must be capable of accurately and precisely determining total hydrocarbons (THC) concentrations on the order of 10 parts per billion-carbon (ppbC) for vehicle tests run under optimum conditions on a bag mini-diluter (BMD) test site. The flame ionization detector (FID) is the standard instrument used in the measurement of THC. Currently, there are many instrument manufacturers that produce these types of analyzers. This paper studies the limit of detection and accuracy capabilities of one of these instruments, the Beckman 400A FID. In addition, the paper shows evidence that supports that this “state of technology” as described by this instrument, is sufficient to meet the demands of the today's most stringent, vehicle emission standards.

Sound absorption is one way to control noise in automotive passenger compartments. Fibrous or porous materials absorb sound in a cavity by dissipating energy associated with a propagating sound wave. The objective of this study was to evaluate the acoustic performance of a cotton fiber absorbing material in comparison to a new polypropylene fibrous material, called ECOSORB ®. The acoustical evaluation was done using measurements of material properties along with sound pressure level from road testing of a fully-assembled vehicle. The new polypropylene fibrous material showed significant advantages over the cotton fiber materials in material properties testing and also in-vehicle measurements. In addition to the performance benefits, the polypropylene absorber provided weight savings over the cotton fiber material.

Noise due to the flow over an automobile A-pillar rain gutter in isolation was computed using a two step procedure. Initially the flow solution was obtained by solving the Reynolds Averaged Navier Stokes (RANS) equations. Acoustical Sources were extracted from the flow solution and propagated to the far-field using the Lighthill-Curle equation. Experiments were conducted to evaluate the computations. Compared results include steady pressures, time dependent pressures, and sound intensity levels. Computed results and experimental data were reduced in a similar way to ensure a one to one comparison. Computed results are in good agreement with the experimental values. A-weighted noise levels are predicted reasonably well.

The Honda Particulate Matter Index (PMI) is a very helpful tool which provides an indication of a fuel’s sooting tendency. Currently, the index is being used by various laboratories and vehicle OEMs as a metric to understand a fuels impact on automotive engine sooting, in preparation for new global emissions regulations. The calculation of the index involves generating detailed hydrocarbon analysis (hydrocarbon molecular speciation) using gas chromatography laboratory equipment and the PMI calculation requires the exact list of compounds and correct naming conventions to work properly. The analytical methodology can be cumbersome, when the gas chromatography methodology has to be adjusted for new compounds that are not in the method, or if the compounds are not matching the list for quantification. Also, the method itself is relatively expensive, and not easily transferrable between labs.

Thermal effectiveness of Exhaust Gas Recirculation (EGR) coolers used in diesel engines can progressively decrease and stabilize over time due to inner fouling layer of the cooler tubes. Thermophoretic force has been identified as the major cause of diesel exhaust soot fouling, and models are proposed in the literature but improvements in simulation are needed especially for the long-term trend of soot deposition. To describe the fouling stabilization behavior, a removal mechanism is required to account for stabilization of the soot layer. Observations from previous experiments on surrogate circular tubes suggest there are three primary factors to determine removal mechanisms: surface temperature, thickness, and shear velocity. Based on this hypothesis, we developed a 1D CFD fouling model for predicting the thermal effectiveness reduction of real EGR coolers. The model includes the two competing mechanisms mentioned that results in fouling balance.

This work provides an effective engineering method of building a part-load engine simulation model from a wide-open throttle (WOT) engine model and available dynamometer data. It shows how to perform part-load engine simulation using optimizer for targeted manifold absolute air pressure (MAP) on a basic matrix of engine speed and MAP. Key combustion parameters were estimated to cover the entire part-load region based on affordable assumptions and limitations. Engine rubbing friction and pumping friction were combined to compare against the motoring torque. The emission data from GM dynamometer laboratory were used to compare against engine simulation results after attaching the RLT sensor to record emission data in the engine simulation model.

The evaluation of the performance of a particular inflator for the design of the entire airbag system is typically carried out by examining the pressure pattern in a standard tank test. This study assesses the adequacy of the tank test as a true measure of the likely performance of the actual inflator-airbag system. Theoretical arguments, numerical experiments, and physical experiments show that the time rate of pressure change may be an appropriate measure to evaluate performance of a specific type of inflator, particularly if variations in the inflator design maintain the same working gas components. However, when evaluating and comparing the dynamic behavior between different types of inflators, the time rate of pressure change provides useful but incomplete information.

Stringent fuel economy and emissions regulations have driven development of new mixture preparation technologies and increased spark-ignition engine complexity. Additional degrees of freedom, brought about by devices such as cam phasers and charge motion control valves, enable greater range and flexibility in engine control. This permits significant gains in fuel efficiency and emission control, but creates challenges related to proper engine control and calibration techniques. Accurate experimental characterization of high degree of freedom engines is essential for addressing the controls challenge. In particular, this paper focuses on the evaluation of three experimental residual gas fraction measurement techniques for use in a spark ignition engine equipped with dual-independent variable camshaft phasing (VVT).

An experimental heat release rate analysis was conducted on a six cylinder, 12.7 liter Detroit Diesel Series 60 turbocharged engine operating under steady state conditions. The overall chemical, or gross, rate of heat release and the net apparent rate of heat release were determined from experimental measurements. The gross, time averaged, heat release rate was determined by two separate concepts/methods using exhaust gas concentration measurements from the Nicolet Rega 7000 Real Time Exhaust Gas Analyzer and the measured exhaust gas flow rate. The net apparent rate of heat release was determined from the in-cylinder pressure measurements for each of the six cylinders, averaged over 80 cycles. These pressure measurements were obtained using a VXI based Tektronix data acquisition system and LabVIEW software. A computer algorithm then computed the net apparent rate of heat release from the averaged in-cylinder pressure measurements.

When unexpected integrated lubricant-related problems occur, for example, high-speed operating conditions, lubricants can be degraded and even fail to reach certain automatic transmission parts. Dryout of oil films means a serious lack of lubrication, which may damage the power transmission line and key parts. Dryout of ATF is analogous to that in forced convective boiling and condensation. It thus requires special efforts to determine the mechanics that induce such fluid transport phenomena. This paper presents an experimental investigation of lubricant activities in the main shaft. Dimensional analysis is applied, and flow maps of the air-oil flow and dryout regimes are constructed. Correlations closely agree with the data and reveal the possibility of dryout. Heat transfer effect is briefly discussed.

A series of inflator tank tests was carried out to determine the amount of transient heat losses to the tank wall during these tests. The time history data of tank wall temperature, and tank interior gas temperature and pressure, were measured. The tank wall temperature data were analyzed using an inverse heat conduction method to generate the transient heat loss fluxes from the tank gas to the tank wall. The validity of the results are discussed along with the physical reasoning and experimental observations. This is the first part of an effort in a research project to develop a comprehensive heat transfer model to predict the transient heat losses to the tank wall during the inflator tank test.

This paper proposes a method to make diagnostic/prognostic judgment about the health of a tire, in term of its wear, using existing on-board sensor signals. The approach focuses on using an estimate of the effective rolling radius (ERR) for individual tires as one of the main diagnostic/prognostic means and it determines if a tire has significant wear and how long it can be safely driven before tire rotation or tire replacement are required. The ERR is determined from the combination of wheel speed sensor (WSS), Global Positioning sensor (GPS), the other motion sensor signals, together with the radius kinematic model of a rolling tire. The ERR estimation fits the relevant signals to a linear model and utilizes the relationship revealed in the magic formula tire model. The ERR can then be related to multiple sources of uncertainties such as the tire inflation pressure, tire loading changes, and tire wear.

The equipment for collecting dilute exhaust samples involves the use of bag materials (i.e., Tedlar®) that emit hydrocarbons that contaminate samples. This study identifies a list of materials and treatments to produce bags that reduce contamination. Based on the average emission rates, baked Tedlar®, Capran® treated with alumina deposition, supercritical CO2 extracted Kynar® and supercritical CO2 extracted Teflon NXT are capable of achieving the target hydrocarbon emission rate of less than 15 ppbC per 30 minutes. CO2 permeation tests were also performed. Tedlar, Capran, Kynar and Teflon NXT showed comparable average permeation rates. Based on the criteria of HC emission performance, changes in measured CO2 concentration, ease of sealing, and ease of surface treatment, none of the four materials could be distinguished from one another.

We have developed a methodology for analysis of Premixed Charge Compression Ignition (PCCI) engines that applies to conditions in which there is some stratification in the air-fuel distribution inside the cylinder at the time of combustion. The analysis methodology consists of two stages: first, a fluid mechanics code is used to determine temperature and equivalence ratio distributions as a function of crank angle, assuming motored conditions. The distribution information is then used for grouping the mass in the cylinder into a two-dimensional (temperature-equivalence ratio) array of zones. The zone information is then handed on to a detailed chemical kinetics model that calculates combustion, emissions and engine efficiency information. The methodology applies to situations where chemistry and fluid mechanics are weakly linked.

Thermal distortions of friction disks caused by frictional heating modify pressure distribution on friction surfaces. Pressure distribution, in turn, determines distribution of generated frictional heat. These interdependencies create a complex thermoelastic system that, under some conditions, may become unstable and may lead to severe pressure concentrations with very high local temperature and stress. The phenomenon is responsible for many common thermal failure modes of friction elements and is known as frictionally excited thermoelastic instability (TEI). In the paper, one of the cases of TEI is investigated theoretically and experimentally. The study involves a two-disk structure with one fiction disk and one matching steel disk that have one friction interface. An unsteady heat conduction problem and an elastic contact problem are modeled as axisymmetric ones and are solved using the finite element method.