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Sector mesh modeling is the dominant computational approach for combustion system design optimization. The aim of this work is to quantify the errors descending from the sector mesh approach through three geometric modeling approaches to an optical diesel engine. A full engine geometry mesh is created, including valves and intake and exhaust ports and runners, and a full-cycle flow simulation is performed until fired TDC. Next, an axisymmetric sector cylinder mesh is initialized with homogeneous bulk in-cylinder initial conditions initialized from the full-cycle simulation. Finally, a 360-degree azimuthal mesh of the cylinder is initialized with flow and thermodynamics fields at IVC mapped from the full engine geometry using a conservative interpolation approach. A study of the in-cylinder flow features until TDC showed that the geometric features on the cylinder head (valve tilt and protrusion into the combustion chamber, valve recesses) have a large impact on flow complexity.

In the thermal expansion valve (TXV) refrigerant system, transient high-pitched whistle around 6.18 kHz is often perceived following air-conditioning (A/C) compressor engagements when driving at higher vehicle speed or during vehicle acceleration, especially when system equipped with the high-efficiency compressor or variable displacement compressor. The objectives of this paper are to conduct the noise source identification, investigate the key factors affecting the whistle excitation, and understand the mechanism of the whistle generation. The mechanism is hypothesized that the whistle is generated from the flow/acoustic excitation of the turbulent flow past the shallow cavity, reinforced by the acoustic/structural coupling between the tube structural and the transverse acoustic modes, and then transmitted to evaporator. To verify the mechanism, the transverse acoustic mode frequency is calculated and it is coincided to the one from measurement.

Due to magnesium alloy's poor weldability, other joining techniques such as laser assisted self-piercing rivet (LSPR) are used for joining magnesium alloys. This research investigates the fatigue performance of LSPR for magnesium alloys including AZ31 and AM60. Tensile-shear and coach peel specimens for AZ31 and AM60 were fabricated and tested for understanding joint fatigue performance. A structural stress - life (S-N) method was used to develop the fatigue parameters from load-life test results. In order to validate this approach, test results from multijoint specimens were compared with the predicted fatigue results of these specimens using the structural stress method. The fatigue results predicted using the structural stress method correlate well with the test results.

A deeper understanding of the complex phenomenology associated with the multiphase flow-induced noise and vibration in a dynamic valve is of critical importance to the automotive industry. To this purpose, a two-dimensional axisymmetric numerical model has been developed to simulate the complex processes that are responsible for the noise and vibration in a poppet valve. More specifically, an Eulerian multiphase flow model, a dynamic mesh and a user-defined function are utilized to facilitate the modeling of this complicated two-phase fluid-structure interaction problem. For a two-phase flow through the valve, our simulations showed that the deformation and breakup of gas bubbles in the gap between the poppet and the valve seat generates a vibration that arises primarily from the force imbalance between the spring and the two-phase fluid flow induced forces on the poppet.

The aluminum alloy 7075-T6 has the potential to be used for structural automotive body components as an alternative to boron steel. Although this alloy shows poor formability at room temperature, it has been demonstrated that hot stamping is a feasible sheet metal process that can be used to overcome the forming issues. Hot stamping is an elevated temperature forming operation in which a hot blank is formed and quenched within a stamping die. Attaining a high quench rate is a critical step of the hot stamping process and corresponds to maximum strength and corrosion resistance. This work looks at measuring the quench rate of AA7075-T6 by way of three different approaches: water, a water-cooled plate, and a bead die. The water-cooled plate and the bead die are laboratory-scale experimental setups designed to replicate the hot stamping/die quenching process.

No two battery cells can be identical. Charging/discharging a battery pack without monitoring cell voltages or SoC (State-of-Charge) will cause cell voltages to deviate over time and the packs useable capacity to decrease quickly. To redistribute charge uniformly among cells, various cell balancing methods have been proposed in the literature. In this paper, a cell balancing method based on a single switched-capacitor is presented from a brand new perspective. Unlike the traditional balancing methods that rely on the voltage divergence criterion, this paper uses the SoC divergence criterion to shuttle charge from a highly charged cell to a poorly charged cell. Moreover, an equivalent resistance of the single-switched capacitor topology is derived in steady state. For fast cell balancing, design guidelines are provided for selecting a proper switching-time period and the capacitor parameters. Ultracapacitors are recommended to achieve this goal.

The Reverse Braking Assist (RBA) feature is designed to automatically activate full braking in a backing vehicle. When this feature activates, a backing vehicle is suddenly stopped or may slide to a stop. During this process, an understanding of the driver's behavior may be useful in the design of an appropriate human-machine-interface (HMI) for the RBA. Several experimental studies were done to examine driver behavior in response to an unexpected and automatic braking event while backing [1]. Two of these studies are reported in this paper. A 7-passenger Crossover Utility Vehicle was fitted with a rear-view camera, a center-stack mounted LCD screen, and ancillary recording devices. In the first study, an object was suddenly placed in the path of a backing vehicle. The backing vehicle came to a sudden and complete stop. The visual image of the backing path on the LCD prominently showed that an obstacle was present in the backing path of the vehicle.

The pneumatic air brake system for heavy commercial trucks is composed by a large number of components, aiming its proper work and compliance with rigorous criteria of vehicular safety. One of those components, present along the whole vehicle, is the air brake tube, ducts which feed valves and reservoirs with compressed air, carrying signals for acting or releasing the brake system. In 2011, due to a lack of butadiene in a global scale, the manufacturing of these tubes was compromised; as this is an important raw material present on the polymer used so far, PA12. This article introduces the methodology of selecting, developing and validating in vehicle an alternative polymer for this application. For this purpose, acceptance criteria have been established through global material specifications, as well as bench tests and vehicular validation requirements.

Two combustion systems were developed and optimized for an engine for a power cylinder of 0.8-0.9L/cylinder. The first design was a re-entrant bowl concept which was based on the combustion system of a smaller engine with roughly 0.5L/cylinder. The second design was a chamfered bowl concept, a variant of a reentrant bowl that deliberately splits fuel between the bowl and the squish region. For each combustion system concept, nozzle tip protrusion, swirl, and nozzle configuration (number of holes, nozzle flow, and spray angle) were optimized. Several similarities between combustion system concepts were noted, including the optimal swirl and number of holes. The resulting optimums for each concept were compared. The chamfered combustion system was found to have better part-load emissions and fuel consumption tradeoffs. Full load performance was similar at low speed between the two combustion systems, but the reentrant combustion system had advantages at high engine speed and load.

The ISO TC22/SWG2 - Brake Lining Committee established a task force to determine and analyze root causes for variability during dynamometer brake performance testing. SAE paper 2010-01-1697 “Brake Dynamometer Test Variability - Analysis of Root Causes” [1] presents the findings from the phases 1 and 2 of the “Test Variability Project.” The task force was created to address the issue of test variability and to establish possible ways to improve test-to-test and lab-to-lab correlation. This paper presents the findings from phase 3 of this effort-description of factors influencing test variability based on DOE study. This phase concentrated on both qualitative and quantitative description of the factors influencing friction coefficient measurements during dynamometer testing.

Turbocharged gasoline engines are typically equipped with a compressor anti-surge valve or CBV (compressor by-pass valve). The purpose of this valve is to release pressurized air between the throttle and the compressor outlet during tip-out maneuvers. At normal operating conditions, the CBV is closed. There are two major CBV mounting configurations. One is to mount the CBV on the AIS system. The other is to mount the CBV directly on the compressor housing, which is called an integrated CBV. For an integrated CBV, at normal operating conditions, it is closed and the enclosed passageway between high pressure side and low pressure side forms a “side-branch” in the compressor inlet side (Figure 12). The cavity modes associated with this “side-branch” could be excited by shear layer flow and result in narrow band flow noises.

Recent advances in morphing, simulation, and optimization technologies have enabled analytically driven aerodynamic shape optimization to become a reality. This paper will discuss the integration of these technologies into a single process which enables the aerodynamicist to optimize vehicle shape as well as gain a much deeper understanding of the design space around a given exterior theme.

A new, 1-D analytical engine thermal management tool was developed to model piston, oil and coolant temperatures in the Ford 3.5L engine family. The model includes: a detailed lubrication system, including piston oil-squirters, which accurately represents oil flow rates, pressure drops and component heat transfer rates under non-isothermal conditions; a detailed coolant system, which accurately represents coolant flow rates, pressure drops and component heat transfer rates; a turbocharger model, which includes thermal interactions with coolant, oil, intake air and exhaust gases (modeled as air), and heat transfer to the surroundings; and lumped thermal models for engine components such as block, heads, pistons, turbochargers, oil cooler and cooling tower. The model was preliminarily calibrated for the 3.5L EcoBoost™ engine, across the speed range from 1500 to 5500 rpm, using wide-open-throttle data taken from an early heat rejection study.

Emerging markets and South America in particular, have quickly become the cornerstone of major automotive companies in recent years. Currently, all major players are located in the region, and this has created an excellent environment for developing market-tailored products. The trend in the design and technology community is one which allows the final customer to improve his own safety and reduce overall power consumption. Throughout the entire automotive industry, the lighting system has always had a very important role to play during its long history. In the past 50 years, vehicular lighting has achieved an important status due to its close relationship by enhancing passenger and vehicle security. In addition, there is still room for improvement in the halogen front lighting system. Particularly, it is of utmost importance to highlight the implementation of NEO (new efficient optics).

Effects of fuel cell material properties on water management were numerically investigated using Volume of Fluid (VOF) method in the FLUENT. The results show that the channel surface wettability is an important design variable for both serpentine and interdigitated flow channel configurations. In a serpentine air flow channel, hydrophilic surfaces could benefit the reactant transport to reaction sites by facilitating water transport along channel edges or on channel surfaces; however, the hydrophilic surfaces would also introduce significantly pressure drop as a penalty. For interdigitated air flow channel design, it is observable that liquid water exists only in the outlet channel; it is also observable that water distribution inside GDL is uneven due to the pressure distribution caused by interdigitated structure. An in-situ water measurement method, neutron imaging technique, was used to investigate the water behavior in a PEM fuel cell.

A test cell was developed for evaluating a 6-speed automatic transmission. The target vehicle had an internal combustion 5.4L gasoline V8 engine. An electric dynamometer was used to closely simulate the engine characteristics. This included generating mean torque from the ECU engine map, with a transient capability of 10,000 rpm/second. Engine inertia was simulated with a transient capability of 20,000 rpm/second, and torque pulsation was simulated individually for each piston, with a transient capability of 50,000 rpm/second. Quantitative results are presented for the correlation between the engine driven and the dynamometer driven transmission performance over more than 60 test cycles. Concerns about using the virtual engine in validation testing are discussed, and related to the high frequency transient performance required from the electric dynamometer. Qualitative differences between the fueled engine and electric driven testing are presented.

Nowadays is a common sense the importance of the CAE usage in the modern automotive industry. The ability to predict the design behavior of a project represents a competitive advantage. However, some CAE models have become so complex and detailed that, in some cases, one just can not build up the model without a considerable amount of information. In that case simplified models play an important role in the design phase, especially in pre-program stages. This work intends to build an archetypal vehicle dynamics model able to predict the rollover resistance of a vehicle design. Through the study of a more complex model, carried out in Adams environment, it was possible to identify the key degrees of freedom to be considered in the simplified model along with important elements of the suspension which are also important design factors.

Exhaust gas temperature is often measured with a device such as thermocouple or RTD (Resistance Temperature Detector). An alternative method to determine the gas temperature would be to use an existing gas sensor heating mechanism to perform as a temperature sensor. A planar type FLOH (Fast Light Off HEGO-Heated Exhausted Gas Oxygen) sensor under transient vehicle speed/load conditions is suited to this function and was modeled to predict the exhaust gas temperature. The numerical input to the model includes exhaust flow rate, heater voltage, and heater current. Laboratory experiments have been performed to produce an equation relating the resistance of the heater and the temperature of the sensor (heater), which provides a method to indirectly determine HEGO sensor temperature.

Phosphorus contamination from engine oil additives has been associated with reduced performance of vehicle-aged exhaust gas catalysts. Identifying phosphorus species on aged catalysts is important for understanding the reasons for catalytic performance degradation. However, phosphorus is present only in small quantities, which makes its detection with bulk analytical techniques difficult. Raman microscopy probes small regions (a few microns in diameter) of a sample, and can detect both crystalline and amorphous materials. It is thus ideal for characterizing phosphates that may have limited distribution in a catalyst. However, suitable Raman spectra for mixed-metal phosphates that might be expected to be present in contaminated catalysts are not generally available.

A co-operative program initiated by the Automotive Aluminum Alliance and supported by USAMP continues to pursue the goal of establishing an in-laboratory cosmetic corrosion test for finished aluminum auto body panels that provides a good correlation with in-service performance. The program is organized as a task group within the SAE Automotive Corrosion and Protection (ACAP) Committee. Initially a large reservoir of test materials was established to provide a well-defined and consistent specimen supply for comparing test results. A series of laboratory procedures have been conducted on triplicate samples at separate labs in order to evaluate the reproducibility of the various lab tests. Exposures at OEM test tracks have also been conducted and results of the proving ground tests have been compared to the results in the laboratory tests. Outdoor tests and on-vehicle tests are also in progress. An optical imaging technique is being utilized for evaluation of the corrosion.