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This paper presents the characterization of the random noise in driveline output shaft torque measurements that is commonly induced by road disturbances. To investigate the interaction between the shaft torque and road side excitation, torque signals are measured using a magnetoelastic torque sensor, as well as a conventional strain gauge sensor, under various types of road surfaces and conditions such as unevenness. A generalized de-trending method for producing a stationary random signal is first conducted. Statistical methods, in particular the probability density function and transform technique, are utilized to provide an evident signature for identifying the road excitation effect on the vehicle output shaft torque. Analysis results show how the road surface can act as a disturbance input to the vehicle shaft torque.

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.

Closed-form stress intensity factor solutions at the critical locations of spot welds in four types of commonly used specimens are obtained based on elasticity theories and fracture mechanics. The loading conditions for spot welds in the central parts of four types of specimens are first examined. The resultant loads on the weld nugget and the self-balanced resultant loads on the lateral surface of the central parts of the specimens are then decomposed into various types of symmetric and anti-symmetric parts. Closed-form structural stress and stress intensity factor solutions for spot welds under various types of loading conditions are then adopted from a recent work of Lin and Pan to derive new closed-form stress intensity factor solutions at the critical locations of spot welds in the four types of specimens.

Fatigue behaviors of aluminum 5754-O spot friction welds made by a concave tool in lap-shear specimens are investigated based on experimental observations and a fatigue life estimation model. Optical micrographs of the welds before and after failure under quasi-static and cyclic loading conditions are examined. The micrographs indicate that the failure modes of the 5754 spot friction welds under quasi-static and cyclic loading conditions are quite different. The dominant kinked fatigue cracks for the final failures of the welds under cyclic loading conditions are identified. Based on the experimental observations of the paths of the dominant kinked fatigue cracks, a fatigue life estimation model based on the stress intensity factor solutions for finite kinked cracks is adopted to estimate the fatigue lives of the welds.

In this investigation, dissimilar 5754/7075 and 7075/5754 spot friction welds were first made under different processing conditions. The spot friction welds in lap-shear specimens were tested under quasi-static loading conditions. The optimal processing times to maximize the failure loads of the 5754/7075 and 7075/5754 welds under lap-shear loading conditions are identified. The maximum failure load of the 7075/5754 welds is about 40% larger than that of the 5754/7075 welds. Optical micrographs of both types of spot friction welds made at different processing times before and after failure are examined. The micrographs show different weld geometries and different failure modes of spot friction welds made at different processing times. The failure modes of the 5754/7075 and 7075/5754 spot friction welds appear to be quite complex and strongly depend on the geometry and the strength of the interfacial surface between the two deformed sheet materials.

The greatest demand facing the automotive industry has been to provide safer vehicles with high fuel efficiency at minimum cost. Current automotive vehicle structures have one fundamental handicap: a short crumple zone for crash energy absorption. This leaves limited room for further safety improvement, especially for high-speed crashes. Breakthrough technologies are needed. One potential breakthrough is to use active devices instead of conventional passive devices. An innovative inflatable bumper concept [1], called the “I-bumper,” is being developed by the authors for crashworthiness and safety of military and commercial vehicles. The proposed I-bumper has several active structural components, including a morphing mechanism, a movable bumper, two explosive airbags, and a morphing lattice structure with a locking mechanism that provides desired rigidity and energy absorption capability during a vehicular crash.

Near-term energy policy for ground transportation is likely to have a strong focus on both gains in efficiency as well as the use of alternate fuels; as both can reduce crude oil dependence and carbon loading on the environment. Stratified-charge spark-ignition direct-injection (SIDI) engines are capable of achieving significant gains in efficiency. In addition, these engines are likely to be run on alternative fuels. Specifically, lower alcohols such as ethanol and iso-butanol, which can be produced from renewable sources. SIDI engines, particularly the spray-guided variant, tend to be very sensitive to mixture preparation since fuel injection and ignition occur within a short time of each other. This close spacing is necessary to form a flammable mixture near the spark plug while maintaining an overall lean state in the combustion chamber. As a result, the physical properties of the fuel have a large effect on this process.

The hybrid Finite Element Analysis (hybrid FEA) has been developed for performing structure-borne computations in automotive vehicle structures [1, 2 and 3]. The hybrid FEA method combines conventional FEA with Energy FEA (EFEA). Conventional FEA models are employed for modeling the behavior of the stiff members in a system. Appropriate damping and spring or mass elements are introduced in the connections between stiff and flexible members in order to capture the presence of the flexible members during the analyses of the stiff ones. The component mode synthesis method is combined with analytical solutions for determining the driving point conductance at joints between stiff and flexible members and for defining the properties of the concentrated elements which represent the flexible members when analyzing the stiff components.

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.

The spark process has previously been shown to heavily influence ignition stability, particularly in direct-injected gasoline engines. Despite this influence, few studies have addressed spark behavior in direct-injected engines. This study examines the role of environmental factors on the behavior of the spark. Through measurement of the spark duration, by way of the ignition current trace, several observations are made on the influence of external factors on the behavior of the spark. Changing the level of nitrogen in the cylinder (to simulate EGR), the level of wetting and velocity imparted by the spray, the ignition dwell time and the orientation of the ground strap, observations are made as to which conditions are likely to produce unfavorable (shorter) spark durations. Through collection of a statistically significant number of sample spark lengths under each condition, histograms have been assembled and compared under each case.

A new development in the area of the hybrid Finite Element Analysis (hybrid FEA) is presented. The hybrid FEA method combines the conventional FEA method with energy FEA (EFEA) for analysis of systems that contain both flexible and stiff members, and is suitable for mid-frequency computations. A formulation for analyzing flexible plates spot-welded to stiff beams when the excitation is applied on the stiff members is developed. Conventional FEA models are employed for modeling the behavior of the stiff members in a system. Appropriate damping elements are introduced in the connections between stiff and flexible members in order to capture the presence of the flexible members during the analyses of the stiff ones.

Cam-phasing is increasingly considered as a feasible Variable Valve Timing (VVT) technology for production engines. Additional independent control variables in a dual-independent VVT engine increase the complexity of the system, and achieving its full benefit depends critically on devising an optimum control strategy. A traditional approach relying on hardware experiments to generate set-point maps for all independent control variables leads to an exponential increase in the number of required tests and prohibitive cost. Instead, this work formulates the task of defining actuator set-points as an optimization problem. In our previous study, an optimization framework was developed and demonstrated with the objective of maximizing torque at full load. This study extends the technique and uses the optimization framework to minimize fuel consumption of a VVT engine at part load.

Variable Valve Actuation (VVA) technology provides high potential in achieving high performance, low fuel consumption and pollutant reduction. However, more degrees of freedom impose a big challenge for engine characterization and calibration. In this study, a simulation based approach and optimization framework is proposed to optimize the setpoints of multiple independent control variables. Since solving an optimization problem typically requires hundreds of function evaluations, a direct use of the high-fidelity simulation tool leads to the unbearably long computational time. Hence, the Artificial Neural Networks (ANN) are trained with high-fidelity simulation results and used as surrogate models, representing engine's response to different control variable combinations with greatly reduced computational time. To demonstrate the proposed methodology, the cam-phasing strategy at Wide Open Throttle (WOT) is optimized for a dual-independent Variable Valve Timing (VVT) engine.

A combination of imaging techniques for investigations of highly transient processes and cyclic variations in internal combustion engines is presented. The single high-speed camera setup uses a CMOS camera combined with a two-stage image-intensifier and two excimer lasers. Fuel mixing, ignition and combustion were monitored via planar laser induced fluorescence imaging of toluene as a tracer that was added to iso-octane in combination with the simultaneous recording of light emission from the spark plasma and OH* chemiluminescence of the developing flame. Image frame rates of 12 kHz for hundreds of cycles were achieved. Application to misfire events in a spray-guided gasoline direct-injection engine is described to illustrate the merits of the technique.

A hybrid finite element formulation for analyzing flexible plates connected to stiff frame was developed. The excitation was considered to be applied on the stiff members. Conventional FEA models were employed for modeling the behavior of the stiff members in a system. Appropriate damping elements were introduced in the connections between stiff and flexible members in order to capture the presence of the flexible members during the analyses of the stiff ones. Once the vibration of the stiff members and the amount of power dissipated at the damping elements was identified, an EFEA analysis was performed in order to determine the amount of vibrational energy in the flexible members. The hybrid FEA is applied to a Body-In-White (BIW). The results of the hybrid FEA are compared with results from very dense conventional finite element analyses.

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.

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.

The transient cone angle of pressure swirl sprays from injectors intended for use in gasoline direct injection engines was measured from 2D Mie scattering images. A variety of injectors with varying nominal cone angle and flow rate were investigated. The general cone angle behavior was found to correlate well qualitatively with the measured fuel line pressure and was affected by the different injector specifications. Experimentally measured modulations in cone angle and injection pressure were forced on a comprehensive spray simulation to understand the sensitivity of pulsating injector boundary conditions on general spray structure. Ignoring the nozzle fluctuations led to a computed spray shape that inadequately replicated the experimental images; hence, demonstrating the importance of quantifying the injector boundary conditions when characterizing a spray using high-fidelity simulation tools.

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.

In this paper, the fatigue failure of the primary roller used in a crankshaft fillet rolling process is investigated by a failure analysis and a two-dimensional finite element analysis. The fillet rolling process is first discussed to introduce the important parameters that influence the fatigue life of the primary roller. The cross sections of failed primary rollers are then examined by an optical microscope and a Scanning Electron Microscope (SEM) to understand the microscopic characteristics of the fatigue failure process. A two-dimensional plane strain finite element analysis is employed to qualitatively investigate the influences of the contact geometry on the contact pressure distribution and the Mises stress distribution near the contact area. Fatigue parameters of the primary rollers are then estimated based on the Findley fatigue theory.