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Technical Paper

Is Toluene a Suitable LIF Tracer for Fuel Film Measurements?

2004-03-08
2004-01-1355
Quantitative LIF measurements of liquid fuel films on the piston of direct-injected gasoline engines are difficult to achieve because generally these films are thin and the signal strength is low. Additionally, interference from scattered laser light or background signal can be substantial. The selection of a suitable fluorescence tracer and excitation wavelength plays an important role in the success of such measurements. We have investigated the possibility of using toluene as a tracer for fuel film measurements and compare it to the use of 3-pentanone. The fuel film dynamics in a motored engine at different engine speeds, temperatures and in-cylinder swirl levels is characterized and discussed.
Technical Paper

Friction Measurement in the Valve Train with a Roller Follower

1994-03-01
940589
The valve train was instrumented to record the instantaneous roller speed, roller pin friction torque, pushrod forces, and cam speed. Results are presented for one exhaust valve of a motored Cummins L-10 engine. The instantaneous cam/roller friction force was determined from the instantaneous roller speed and the pin friction torque. The pushrod force and displacement were also measured. Friction work loss was determined for both cam and roller interface as well as the upper valve train which includes the valve pushrod, rocker arm, valve guide, and valve. Roller follower slippage on the cam was also determined. A kinematic analysis with the measured data provided the normal force and contact stress at cam/roller interface.(1) Finally, the valve train friction was found to be in the mixed lubrication regime.(2) Further efforts will address the theoretical analysis of valve train friction to predict roller slippage.
Technical Paper

Investigation of Dummy Response and Restraint Configuration Factors Associated with Upper Spinal Cord Injury in a Forward-Facing Child Restraint

1993-11-01
933101
Dummy response and restraint configuration factors associated with a known child injury environment were investigated using a spinal-cord injury accident case, a full-scale reconstruction, and sled simulations. The work is one of several studies undertaken in association with the International Task Force on Child Restraining Systems to support the development of improved neck injury criteria and restraint systems for young children. A two-vehicle crash involving a restrained child occupant was investigated in detail and reconstructed in full-scale at the Transport Canada Motor Vehicle Test Centre using the CRABI 6-Month dummy. Vehicle damage and crush characteristics closely resembled that of the case vehicles. Dummy instrumentation included head and chest accelerometers and upper and lower neck transducers. The case occupant had been facing forward and had sustained a contusion of the spinal cord at T2 that resulted in paraplegia.
Technical Paper

Child Restraint and Airbag Interaction: Problem and Progress

1993-11-01
933094
The nature of the potentially hazardous interaction between a passenger-side airbag and a rear-facing child restraint is described, as well as the expectations regarding airbag interaction with other types of child restraint systems. Progress made in developing tools to study the problem and test criteria to evaluate possible solutions are summarized, efforts to inform the public are noted, and promising directions for dealing with the problem are addressed. Primary emphasis is placed on the work of the Society of Automotive Engineers (SAE) Child Restraint and Airbag Interaction (CRABI) Task Force and that of its members.
Technical Paper

A Survey of Alcohol as a Motor Fuel

1964-01-01
640648
Alcohol has been promoted and used as a motor fuel for more than 50 years. However, United States ethyl alcohol production is small compared with gasoline production. High latent heat of vaporization of alcohol makes possible some increase of power over gasoline. The heating value of alcohol is low and energy content of alcohol blends is less than that of gasoline; fuel consumption of blends is therefore increased. The ability of ethanol to improve the octane number of gasoline has diminished as the octane number of gasoline has improved. There is no published evidence that alcohols can appreciably reduce air pollution problems.
Technical Paper

A Survey of Automotive Occupant Restraint Systems: Where We’ve Been, Where We Are and Our Current Problems

1969-02-01
690243
In recent years, automotive occupant restraint system development has gained impetus, stimulated, in part, by new federal standards. But in the resolution of the basic question of whether automobiles should be equipped with restraints, many new problems have arisen, including, ironically, some brought on by regulation. While there is little doubt that restraint systems can provide the single most important contribution to occupant protection, such restraint systems remain useless unless adequately installed and properly worn. Current problems involve not only what concepts provide most promise for future restraint systems, but diverse and often conflicting industry and governmental opinion about what are the best interests of the motoring public. Restraints are still not provided in buses, trucks, and utility vehicles. In addition, the problems of child and infant restraints and restraints for retrofit in older vehicles remain unresolved.
Technical Paper

Modeling of Diesel Combustion and NO Emissions Based on a Modified Eddy Dissipation Concept

2004-03-08
2004-01-0107
This paper reports the development of a model of diesel combustion and NO emissions, based on a modified eddy dissipation concept (EDC), and its implementation into the KIVA-3V multidimensional simulation. The EDC model allows for more realistic representation of the thin sub-grid scale reaction zone as well as the small-scale molecular mixing processes. Realistic chemical kinetic mechanisms for n-heptane combustion and NOx formation processes are fully incorporated. A model based on the normalized fuel mass fraction is implemented to transition between ignition and combustion. The modeling approach has been validated by comparison with experimental data for a range of operating conditions. Predicted cylinder pressure and heat release rates agree well with measurements. The predictions for NO concentration show a consistent trend with experiments. Overall, the results demonstrate the improved capability of the model for predictions of the combustion process.
Technical Paper

Testing and Modeling of Frequency Drops in Resonant Bending Fatigue Tests of Notched Crankshaft Sections

2004-03-08
2004-01-1501
Resonant frequencies of a resonant bending system with notched crankshaft sections are obtained experimentally and numerically in order to investigate the effect of notch depth on the drop of the resonant frequency of the system. Notches with the depths ranging from 1 to 5 mm, machined by an EDM (Electrical-Discharging Machining) system, were introduced in crankshaft sections at the fillet between the main crank pin and crank cheek. The resonant frequencies of the resonant bending system with the crankshaft sections with various notch depths were first obtained from the experiments. Three-dimensional finite element models of the resonant bending system with the crankshafts sections with various notch depths are then generated. The resonant frequencies based on the finite element computations are in good agreement with those based on the experimental results.
Technical Paper

First Order Analysis for Automotive Body Structure Design - Part 3: Crashworthiness Analysis Using Beam Elements

2004-03-08
2004-01-1660
We have proposed First Order Analysis (FOA) as a method, which the engineering designers themselves can use easily in an initial design stage. In this paper, we focus on the crashworthiness, and present the method to predict the collapse behavior of the frame member. This method is divided into two parts. Those are (1) collapse analysis under loading conditions of combined axial force and bending moment to the cantilever, and (2) collapse analysis of structural member considering the previously obtained moment - rotation angle relationship using the beam element. In comparison with the results according to the detailed Finite Element Analysis (FEA) model, effectiveness and validity of this method are presented.
Technical Paper

Comparison of Diesel Oxidation Catalyst Performance on an Engine and a Gas Flow Reactor

2007-04-16
2007-01-0231
This paper analyzes and compares reactor and engine behavior of a diesel oxidation catalyst (DOC) in the presence of conventional diesel exhaust and low temperature premixed compression ignition (PCI) diesel exhaust. Surrogate exhaust mixtures of n-undecane (C11H24), ethene (C2H4), CO, O2, H2O, NO and N2 are defined for conventional and PCI combustion and used in the gas flow reactor tests. Both engine and reactor tests use a DOC containing platinum, palladium and a hydrocarbon storage component (zeolite). On both the engine and reactor, the composition of PCI exhaust increases light-off temperature relative to conventional combustion. However, while nominal conditions are similar, the catalyst behaves differently on the two experimental setups. The engine DOC shows higher initial apparent HC conversion efficiencies because the engine exhaust contains a higher fraction of trappable (i.e., high boiling point) HC.
Technical Paper

Numerical Modeling of Cross Flow Compact Heat Exchanger with Louvered Fins using Thermal Resistance Concept

2006-04-03
2006-01-0726
Compact heat exchangers have been widely used in various applications in thermal fluid systems including automotive thermal management systems. Radiators for engine cooling systems, evaporators and condensers for HVAC systems, oil coolers, and intercoolers are typical examples of the compact heat exchangers that can be found in ground vehicles. Among the different types of heat exchangers for engine cooling applications, cross flow compact heat exchangers with louvered fins are of special interest because of their higher heat rejection capability with the lower flow resistance. In this study, a predictive numerical model for the cross flow type heat exchanger with louvered fins has been developed based on the thermal resistance concept and the finite difference method in order to provide a design and development tool for the heat exchanger. The model was validated with the experimental data from an engine cooling radiator.
Technical Paper

A Multi-Variable High-Speed Imaging Study of Ignition Instabilities in a Spray-Guided Direct-Injected Spark-Ignition Engine

2006-04-03
2006-01-1264
Ignition stability was studied in an optical spray guided spark ignition direct injection engine. The impact of intake air dilution with nitrogen, spark plug orientation, ignition system dwell time, and fuel injector targeting was addressed. Crank angle resolved fuel distributions were measured with a high-speed planar laser-induced fluorescence technique for hundreds of consecutive cycles. IMEP, COV of IMEP, burn rates and spark energy delivered to the gas were examined and used in conjunction with the imaging data to identify potential reasons for misfires.
Technical Paper

Design and Development of a Turbocharged E85 Engine for Formula SAE Racing

2008-06-23
2008-01-1774
A summary of the design and development process for a Formula SAE engine is described. The focus is on three fundamental elements on which the entire engine package is based. The first is engine layout and displacement, second is the fuel type, and third is the air induction method. These decisions lead to a design around a 4-cylinder 600cc motorcycle engine, utilizing a turbocharger and ethanol E-85 fuel. Concerns and constraints involved with vehicle integration are also highlighted. The final design was then tested on an engine dynamometer, and finally in the 2007 M-Racing FSAE racecar.
Technical Paper

The Influence of Inlet Air Conditions on Carburetor Metering

1966-02-01
660119
This paper provides data concerning the enrichment of automotive carburetors with variation of inlet air pressure and temperature. These changes occur with weather and the seasons, with altitude, and because of underhood heating. The early opening of the conventional carburetor enrichment value at altitude can add greatly to the “ normal” carburetor enrichment. Means for compensating the mixture ratio for these changes in inlet air conditions are known, but will almost certainly add to the complexity and cost of the engine induction system. The cost of improved devices must be compromised with the possible reduction in exhaust emissions and improvement in fuel economy.
Technical Paper

Investigation of Airbag-Induced Skin Abrasions

1992-11-01
922510
Static deployments of driver-side airbags into the legs of human subjects were used to investigate the effects of inflator capacity, internal airbag tethering, airbag fabric, and the distance from the module on airbag-induced skin abrasion. Abrasion mechanisms were described by measurements of airbag fabric velocity and target surface pressure. Airbag fabric kinematics resulting in three distinct abrasion patterns were identified. For all cases, abrasions were found to be caused primarily by high-velocity fabric impactrather than scraping associated with lateral fabric motion. Use of higher-capacity inflators increased abrasion severity, and untethered airbags produced more severe abrasions than tethered airbags at distances greater than the length of the tether. Abrasion severity decreased as the distance increased from 225 to 450 mm. Use of a finer-weave airbag fabric in place of a coarser-weave fabric did not decrease the severity of abrasion.
Technical Paper

Characterization of Combustion and NO Formation in a Spray-Guided Gasoline Direct-Injection Engine using Chemiluminescence Imaging, NO-PLIF, and Fast NO Exhaust Gas Analysis

2005-05-11
2005-01-2089
The spatial and temporal formation of nitric oxide in an optical engine operated with iso-octane fuel under spray-guided direct-injection conditions was studied with a combination of laser-induced fluorescence imaging, UV-chemiluminescence, and cycle resolved NO exhaust gas analysis. NO formation during early and late (homogeneous vs. stratified) injection conditions were compared. Strong spatial preferences and cyclic variations in the NO formation were observed depending on engine operating conditions. While engine-out NO levels are substantially lower for stratified engine operation, cyclic variations of NO formation are substantially higher than for homogeneous, stoichiometric operation.
Technical Paper

Inhomogeneities in HCCI Combustion: An Imaging Study

2005-05-11
2005-01-2122
A four-valve-pentroof, direct-injection, optical engine fueled with n-heptane has been operated at four different steady-state HCCI operating conditions including 10% and 65% residuals, both at low and high swirl conditions. Both, planar toluene LIF and volume chemiluminescence show large scale inhomogeneity in the ensemble averaged images. The interpretation of the toluene-tracer LIF signals (when premixed with the fresh-air charge) as a marker for reaction homogeneity is discussed. A binarization scheme and a statistical analysis of the LIF images were applied to the per-cycle planar-LIF images revealing inhomogeneities both from cycle-to-cycle and within the regions of individual cycles that track with the average heat release rate. Comparison of these two homogeneity metrics between the four operating conditions reveals weak but discernable differences.
Technical Paper

Real Time Detection Filters for Onboard Diagnosis of Incipient Failures

1989-02-01
890763
This paper presents the real time implementation of detection filters for the diagnosis of incipient failures in electronically controlled internal combustion (IC) engines. The detection filters are implemented in a production vehicle. Recent results [1] have demonstrated the feasibility of a model-based failure detection and isolation (FDI) methodology for detecting partially failed components in electronically controlled vehicle subsystems. The present paper describes the real time application of the FDI concept to the detection of faults in sensors associated with the engine/controller In a detection filter, the performance of the engine/controller system is continuously compared to a prediction based on sensor measurements and an analytical model (typically a control model) of the system. Any discrepancy between actual and predicted performance is analyzed to identify the unique failure signatures related to specific system components.
Technical Paper

Model Analysis of a Diesel Engine Cylinder Block using HEXA8 Finite Elements - Analysis and Experiment

1988-10-01
881853
Analytical and experimental investigations of a diesel engine cylinder block are performed. An attempt is made to reduce modeling and analysis costs in the design process of an engine. Traditionally, the engine has been modeled using either 8-node or 20-node solid elements for stress and thermal analyses and modeled using 4-node plate and shell elements for the dynamic analysis. In this paper, a simpler finite element modeling technique using only 8 node solid elements for both dynamic and static analyses is presented. Based on this integrated modeling technique of finite elements, eigenvalues are calculated and compared with the experimental data obtained from modal testing of an actual engine cylinder block.
Technical Paper

Efficient Engine Models Using Recursive Formulation of Multibody Dynamics

2001-04-30
2001-01-1594
Engine models with fully coupled dynamic effects of the engine components can be constructed through the use of commercial multibody dynamics codes, such as ADAMS and DADS. These commercial codes provide a modeling platform for very general mechanical systems and the time and effort required to learn how to use them may preclude their use for some engine designers. In this paper, we review an alternative and specialized modeling platform that functions as a template for engine design. Relative to commercial codes, this engine design template employs a recursive formulation of multibody dynamics, and thus it leads directly to the minimum number of equations of motion describing the dynamic response of the engine by a priori satisfaction of kinematic constraints. This is achieved by employing relative coordinates in lieu of the absolute coordinates adopted in commercial multibody dynamics codes. This engine modeling tool requires only minimal information for the input data.
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