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Time-averaged temperatures at critical locations on the piston of a direct-fuel injected, two-stroke, 388 cm3, research engine were measured using an infrared telemetry device. The piston temperatures were compared to data [7] of a carbureted version of the two-stroke engine, that was operated at comparable conditions. All temperatures were obtained at wide open throttle, and varying engine speeds (2000-4500 rpm, at 500 rpm intervals). The temperatures were measured in a configuration that allowed for axial heat flux to be determined through the piston. The heat flux was compared to carbureted data [8] obtained using measured piston temperatures as boundary conditions for a computer model, and solving for the heat flux. The direct-fuel-injected piston temperatures and heat fluxes were significantly higher than the carbureted piston. On the exhaust side of the piston, the direct-fuel injected piston temperatures ranged from 33-73 °C higher than the conventional carbureted piston.

The need for accurate virtual prototyping prediction is well documented in the literature. For welded body structures one notable shortcoming has been the ability for finite element analysis (FEA) to accurately predict the failure of welded joints due to cyclic loading. A new approach to representing spot-welds for durability evaluation in automotive sheet metal structures is presented here. Excellent correlation with spot-weld failures in actual tests have been observed through this modeling approach. We present a method of representing spot-welds using the finite element method. This method has shown to be able of predicting the behavior of spot-welds prior to the build of any prototypes or testing. Further, for spot-weld failures we present evidence that reveals which radial quadrant of the spot-weld will contain the failure. This method also allows engineers to determine the mechanism of failure. This paper describes in detail the spot-weld modeling method.

ECU designers are seeking more flexibility from HIL test systems. Often their needs are met by the development of custom hardware, either internally or by HIL test system vendors. Many systems also rely heavily on the use of multiple expensive microprocessors to achieve the required timing and synchronization performance. This paper discusses an alternative based on PC technology and reconfigurable I/O hardware. The HIL test system designer uses a graphical programming interface to reconfigure not only the real-time software portion of the system, but also the FPGA-based I/O hardware. This increases flexibility and lowers cost by providing capabilities such as generating simulated outputs synchronized to crank angle and implementing multiple serial communication protocols.

As automotive OEMs (Original Equipment Manufacturer) struggle to reach a balance between Design and Performance, environmental legislations continues to demand more rapid gains in vehicle efficiency. As a result, more attention is being given to the contributions of both tire and wheels. Not only tire rolling resistance, but also tire and wheel aerodynamics are being shown to be contributors to overall efficiency. To date, many studies have been done to correlate CFD simulations of rotating wheels both in open and closed wheeled environments to windtunnel results. Whereas this ensures proper predictive capabilities, little focus has been given to thoroughly explaining the physics that govern this complex environment. This study seeks to exhaustively investigate the complex interactions between the ground, body, and a rotating tire/wheel.

About 10 years ago in the US, an automotive OEM consortium formed the Oxygenated Fuels Task Force which in turn created the SAE Cooperative Research Project Group 2 to develop a simple rational method for qualifying materials. At that time the focus was Methanol/Gasoline blends. This work resulted in SAE J1681, Gasoline/Methanol Mixtures for Materials Testing. Recently this document was rewritten to make it the single, worldwide, generic source for fuel system test fluids. The paper will describe the rationale for selecting the fuel surrogate fluids and why this new SAE standard should replace all existing test fuel or test fluid standards for fuel system materials testing.

An interactive tool for predicting the performance of vehicle designs in the pedestrian leg impact test has been developed. This tool allows users to modify the design of a vehicle front structure through the use of a graphical interface, and then evaluates the performance of the design with a response surface. This performance is displayed in the graphical interface, providing the user with nearly instantaneous feedback to his design changes. An example is shown that demonstrates how the tool can be used to help guide the user towards vehicle designs that are likely to improve performance. As part of the development of this tool, a simplified, parametric finite element model of the front structure of the vehicle was created. This vehicle model included eleven parameters that could be adjusted to change the structural dimensions and structural behavior of the model.

In this work, an experimental and analysis methodology was developed to evaluate the preignition propensity of fuels and engine operating conditions in an SI engine. A heated glow plug was introduced into the combustion chamber to induce early propagating flames. As the temperature of the glowplug varied, both the fraction of cycles experiencing these early flames and the phasing of this combustion in the engine cycle varied. A statistical methodology for assigning a single-value to this complex behavior was developed and found to have very good repeatability. The effects of engine operating conditions and fuels were evaluated using this methodology. While this study is not directly studying the so-called stochastic preignition or low-speed preignition problem, it studies one aspect of that problem in a very controlled manner.

Fast-running metamodels (surrogates or response surfaces) that approximate multivariate input/output relationships of time-consuming CAE simulations facilitate effective design trade-offs and optimizations in the vehicle development process. While the cross-validated nonparametric metamodeling methods are capable of capturing the highly nonlinear input/output relationships, it is crucial to ensure the adequacy of the metamodel error estimates. Moreover, in order to circumvent the so-called curse-of-dimensionality in constructing any nonlinear multivariate metamodels from a realistic number of expensive simulations, it is necessary to reliably eliminate insignificant inputs and consequently reduce the metamodel prediction error by focusing on major contributors. This paper presents a robust data-adaptive nonparametric metamodeling procedure that combines a convergent variable screening process with a robust 2-level error assessment strategy to achieve better metamodel accuracy.

Deionized (DI) water is being used for humidification and cooling on some fuel cell designs. This highly purified water is corrosive, yet the high purity is required to maintain the function and durability of the fuel cell. A study of the deionized water system was undertaken to determine the effect of various materials on water quality, and also to determine the effect of deionized water on each material. The test setup was designed to circulate fluid from a reservoir, similar to an actual application. The fluid temperature, pressure, and flow rate were controlled. The resistivity of the water was observed and recorded. Pre- and post-testing of the water and the materials was performed. The goal is to achieve system cleanliness and durability similar to a stainless steel system using lighter, less expensive materials. This paper describes the test setup, test procedures, and the overall results for the eight materials tested.

48V mild hybrid engine is one of major eco-friendly technology for global CO2 reduction policy. The 48V mild hybrid engine enables to operate torque boost, recuperation and ISG status by MHSG(Mild Hybrid Starter and Generator). The FEAD(Front End Auxiliary Drive) system is a very important role to transfer MHSG power to crankshaft at the mild hybrid engine. The conventional FEAD configuration is relatively simple because it transfers power from crankshaft to auxiliary drive components in one direction. But the FEAD configuration of 48V mild hybrid engine is not simple due to bidirectional power transmission between crankshaft and MHSG. For instance, in case of torque boost mode, the tight side of auxiliary belt is entry span of MHSG. On the contrary, the tight side of auxiliary belt is exit span of MHSG at recuperation mode.

The present work aims to characterize the microstructure of valvetrain camshaft lobes that are currently applied in the automotive industry, obtained by different processing routes. The cam lobe microstructure has been assessed by microscopy, whereas the mechanical properties by hardness profile measurements on the surface region. Microconstituents type and form, composing the final microstructure at the cam lobe work region, are defined by the casting route and/or post-heat treatment process other than alloy chemical composition, so that knowledge and control of processing route is vital to assure suitable valvetrain system assembly performance and durability. Most of the mechanical solicitations on the part occur at the interface between cam and follower; the actual contact area is significantly smaller than the apparent area. As a result, the microstructure at and near the surface performs a direct role on the performance of the valvetrain, cam lobe and its counterpart.

In the North American automotive market, cylinder deactivation by means of engine valve deactivation is becoming a significant enabler in reducing the Brake Specific Fuel Consumption (BSFC) of large displacement engines. This allows for the continued market competitiveness of large displacement spark ignition (SI) engines that provide exceptional performance with reduced fuel consumption. As an alternative to a major engine redesign, the Active Fuel Management™ (AFM™) system is a lower cost and effective technology that provides improved fuel economy during part-load conditions. Cylinder deactivation is made possible by utilizing innovative new base engine hardware in conjunction with an advanced control system. In the GM 3.9L V-6 Over Head Valve (OHV) engine, the standard hydraulic roller lifters on the engine's right bank are replaced with deactivating hydraulic roller lifters and a manifold assembly of oil control solenoids.

The increase in the number of electronic control units (ECUs) in the modern vehicle, combined with increased software complexity and more distributed controls has led to an extreme testing challenge when it comes to the verification and validation of body-control ECUs. In general test engineers have to deal with more software configurations, more closed-loop interaction between ECUs, and more fault conditions than ever before. By adding Unified Diagnostic Services (UDS) over CAN to a Hardware-In-The-Loop (HIL) test system, Lear was able to increase test automation and provide wider test coverage by automating the ECU flashing process, adding diagnostic identifiers and trouble codes to their test scripts, and providing a quick and easy way to exercise ECU I/O. Lear chose to implement their HIL testers on the open PXI[1] hardware platform, utilizing National Instruments' VeriStand software framework.

Engine ECU testing requires sophisticated sensor simulation and event capture equipment. FPGAs are the ideal devices to address these requirements. Their high performance and high flexibility are perfectly suited to the rapidly changing test needs of today's advanced ECUs. FPGAs offer significant advantages such as parallel processing, design scalability, ultra-fast pin-to-pin response time, design portability, and lifetime upgradability. All of these benefits are highly valuable when validating constantly bigger embedded software in shorter duration. This paper discusses the collaboration between Valeo and NI to define, implement, and deploy a graphical, open-source, FPGA-based engine simulation library for ECU verification.

Several advanced signal processing algorithms beyond the FFT such as time-frequency analysis, quefrency, cestrum, wavelet analysis, and AR modeling uses are outlined. These advanced algorithms can solve some sound and vibration challenges that FFT-based algorithms cannot solve. Looking at signal characteristics of a unit under test in the time-frequency plane, it is possible to get a better understanding of signal characteristics. This is an overview of these algorithms and some application examples, such as speaker testing, bearing fault detection, dashboard motor testing, and engine knock detection where they can be applied to NVH applications.

This paper presents an overview of the aerodynamic development of the 2019 Chevrolet Corvette C7 ZR1. Extensive wind tunnel testing and computational fluid dynamics simulations were completed to engineer the ZR1’s aerodynamics to improve lift-to-drag efficiency and track capability over previous Corvette offerings. The ZR1 architecture changes posed many aerodynamic challenges including increased vehicle cooling, strict packaging demands, wider front track width, and aggressive exterior styling. Through motorsports-inspired aerodynamic development, the ZR1 was engineered to overcome these challenges through the creation of new devices such as a raised rear wing and front underwing. The resulting Standard ZR1 achieved a top speed of 212 mph making it the fastest Corvette ever [1]. Optionally, the ZR1 with the ZTK Performance Package provides the highest downforce of any Corvette, generating approximately 950 pounds at the ZTK’s top speed [1].

Historically, power steering shudder, a vibration which occurs while steering a vehicle at low speeds, has been approached with systematic component-swapping experiments. This approach was time consuming and did not necessarily yield satisfactory results. In this paper it is shown that steering shudder can be analytically approached as a control system with a closed-loop limit cycle caused by the interaction of the chassis and the steering system. This approach provides a metric for determining a vehicle's propensity to shudder and allows quick predictions of the results of changing components. The approach is model-based, and incorporates chassis and hydraulic system components. Results obtained from the control systems analysis have been validated by a vehicle study, which showed a strong correlation between subjective evaluations and the stability metric provided by the analysis.

The increasing demand for energy savings in cars of high production volume, especially those classified as emerging market vehicles, has led the automotive industry to focus on several strategies to achieve higher efficiency levels from their systems and components. One of the most diffuse initiatives is reducing weight through the application of the so-called light alloys. An engine cylinder block can contribute nearly two percent of the vehicle's total mass. Special attention and soon repercussion are given when someone decides to apply a light alloy such as the aluminum to this component. Nonetheless, it is known that peculiarities in terms of physical, chemical and mechanical properties, due to the material nature, associated with regional market characteristics make the initial feasibility analysis study definitely one of the most important stages for the material choice decision.

An integrated stochastic design framework that facilitates practical applications involving time-consuming CAE simulations is described. The probabilistic performance measure that addresses stochastic uncertainties in CAE modeling and simulations is used to support design decision-making. Two enabling metamodeling methods using cross-validated radial basis functions (CVRBF) and a corresponding uniform sampling method are introduced to approximate highly nonlinear CAE model input/output relationships. A vehicle restraint system example is used to demonstrate the effectiveness of the proposed framework and enabling techniques.

As one of many pack-level battery simulation approaches developed within the General Motors-led Computer-Aided Engineering of Automotive Batteries (CAEBAT) Phase 1 project, the system approach treats the entire battery pack as a dynamic system which includes multiple engineering disciplines for simulation. It is the most efficient approach of all the CAEBAT battery pack-level approaches in terms of computational time and resources. This paper reports the application of the system approach for a 24-cell liquid-cooled prototype battery pack. It also summarizes the verification of the approach by comparing the simulation results with the measurement data. The results using the system approach are found to have a very good agreement with the measurements.