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In-cabin Noise at low frequency (due to engine or road excitation) is a major issue for NVH engineers. Usually, noise transfer function (NTF) analysis is carried out, due to absence of accurate actual loads for sound pressure level (SPL) analysis. But NTF analysis comes with the challenge of having too many paths (~20 trimmed body attachment locations: engine and suspension mounts, along with 3 directions for each) to work on, which is cumbersome. Physical test transfer path analysis (TPA) is a process of root cause analysis, by which critical contributing paths can be obtained for a problem peak frequency. In addition to that, loads at the attachment points of trimmed body of test vehicle can be derived. Both these outputs are conventionally used in CAE analysis to work on either NTF or SPL. The drawback of this conventional approach is that the critical bands and paths suggested are based on the problem peak frequency of test vehicle which may be different in CAE.

In motorcycle market, there is demand for technology that makes it possible to drive fast safely. One such technology has already been commercialized; control that prevents front lift while enabling maximum acceleration performance. We have developed a more accurate version of this control. In order to maximize acceleration performance, it is necessary to keep front lift angle as close to zero as possible. Reducing output driving force helps to keep the front lift angle low, but if output driving force is reduced too much, it will degrade acceleration performance. Feedback control that reduces output driving force when front lift is detected is effective for optimizing this trade off, but increasing feedback gain too much to reduce front lift angle will cause output driving force to change suddenly, making for a less comfortable ride.

Recent years, ANC (Active Noise Control) technology has been paying attention. However, rather than the noise measures, the noise gives us the impression even running sound for motorcycles. That is, the control method of the engine sound is shifted from the noise reduction to sound design in each manufactures. Therefore, we proposed a method to design the engine sound using Active Sound Quality Control (ASQC) based on the ANC. Specifically, we proposed the algorithm amplifying and reducing the engine specific order components. From the simulation results, the engine specific order components can be amplified and reduced like an equalizer with the proposed algorithm. And, auditory impressions of engine sound controlled by ASQC were investigated using psychoacoustic measurements. 13 stimuli were obtained by applying ASQC for several order components to amplify or reduce their levels.

The number of people experiencing psychological discomfort due to the increasing amount of noise emanating from motor vehicles has been on the rise. Legal regulations define the permissible level of vehicle noise in a given area. Active noise control (ANC) is a noise cancellation method that reduces low-frequency sounds, such as engine noise, effectively. Furthermore, this method is suitable for controlling engine noise because the equipment necessary to perform it is small and does not require a large space for installation. Advances in digital processing technology have increased the scope of ANC’s applications, and it is no longer restricted to use in motor vehicles. The purpose of this study is to demonstrate the effectiveness of the proposed method in reducing the motor vehicle engine noise produced during acceleration. In this study, we attempt to control the engine sounds from a vehicle with a four-cylinder four-stroke engine.

Brake pad to rotor adhesion following exposure to corrosive environments, commonly referred to as “stiction”, continues to present braking engineers with challenges in predicting issues in early phases of development and in resolution once the condition has been identified. The goal of this study took on two parts - first to explore trends in field stiction data and how testing methods can be adapted to better replicate the vehicle issue at the component level, and second to explore the impacts of various brake pad physical properties variation on stiction propensity via a controlled design of experiments. Part one will involve comparison of various production hardware configurations on component level stiction tests with different levels of prior braking experience to evaluate conditioning effects on stiction breakaway force.

The strong focus on reducing brake drag, driven by a historic ramp-up in global fuel economy and carbon emissions standards, has led to renewed research on brake caliper drag behaviors and how to measure them. However, with the increased knowledge of the range of drag behaviors that a caliper can exhibit comes a particularly vexing problem - how should this complex range of behaviors be represented in the overall road load of the vehicle? What conditions are encountered during coastdown and fuel economy testing, and how should brake drag be measured and represented in these conditions? With the Environmental Protection Agency (amongst other regulating agencies around the world) conducting audit testing, and the requirement that published road load values be repeatable within a specified range during these audits, the importance of answering these questions accurately is elevated. This paper studies these questions, and even offers methodology for addressing them.

Due to environmental problems, number of small vehicles with fuel efficiency increases. Since the small vehicles have small deformation space, it is difficult for them to achieve good crashworthiness at a frontal impact accident. Small deformation space usually yields high vehicle deceleration to absorb kinetic energy of the vehicle. The high vehicle deceleration may produce high occupant deceleration and lead to high occupant injury value. For example, North America, Japan and Europe specify head and chest injury value at vehicle's frontal collision. Those injury values tend to be improved if vehicle deceleration decreases. Deceleration of small vehicle with a little deformation space must be adjusted in order to prevent increase of the occupant injury value. A vehicle deceleration is expressed by 9, 18 or 36 discrete variables. A vehicle, an occupant and restraint systems such as seat belts are modeled by masses and a spring to simulate a frontal collision.

Recently, further weight reduction of the car components are demanded for the purpose of fuel-efficient. In particular, the weight reduction of moving parts such as the connecting rod is indispensable for the weight reduction of neighboring parts. The lightweight connecting rod can be accomplished by decrease in cross section of rod part by using high strength steel. However, conventional high strength steel has bad machinability. Therefore, we developed a new high strength steel for connecting rod. The developed steel is based on middle carbon microalloyed steel, and vanadium content is increased to obtain the high yield ratio. As a result, strength of developed steel is 10% higher than the conventional steel. And a weight of new connecting rod can be reduced 8% by using developed steel. This connecting rod had been mass-produced for automobile engine from 2013.

The Chevrolet Volt is an electric vehicle with extended-range that is capable of operation on battery power alone, and on engine power after depletion of the battery charge. First generation Chevrolet Volts were driven over half a billion miles in North America from October 2013 through September 2014, 74% of which were all-electric [1, 12]. For 2016, GM has developed the second-generation of the Volt vehicle and “Voltec” propulsion system. By significantly re-engineering the traction power inverter module (TPIM) for the second-generation Chevrolet Volt extended-range electric vehicle (EREV), we were able to meet all performance targets while maintaining extremely high reliability and environmental robustness. The power switch was re-designed to achieve efficiency targets and meet thermal challenges. A novel cooling approach enables high power density while maintaining a very high overall conversion efficiency.

The main purposes of the KB variant engine development were not only to reduce fuel consumption or to enhance reliability & quality but also to make better productivity for global manufacture. This paper introduces technical approaches of KB, higher thermal efficiency, better performance and emissions, and well balanced product design with such high energy efficiency, and low-cost and global application. Maximum brake torque per displacement is 7% higher and overall engine weight is lighter by 24kg than an existing 1.3L engine. Design feature includes compactness, low noise characteristics and universal production design considered with globally purchasable materials and simple manufacturing requirement. These contribute short production preparation period and short production task time at Suzuki's key overseas local factories e.g., Maruti Suzuki India Limited.

This study involves an application of Principal Component Analysis (PCA) conducted in support of a Design for Six Sigma (DFSS) project. Primary focus of the project is to optimize seat parameters that influence Low Speed Rear Impact (LSRI) whiplash performance. During the DFSS study, the project team identified a need to rank order critical design factors statistically and establish their contribution to LSRI performance. It is also required to develop a transfer function for the LSRI rating in terms of test response parameters that can be used for optimization. This statistical approach resulted in a reliable transfer function that can applied across all seat designs and enabled us to separate vital few parameters from several many.

By adapting vehicle control systems to the skill level of the driver, the overall vehicle active safety provided to the driver can be further enhanced for the existing active vehicle controls, such as ABS, Traction Control, Vehicle Stability Enhancement Systems. As a follow-up to the feasibility study in [1], this paper provides some recent results on data-driven driving skill characterization. In particular, the paper presents an enhancement of discriminant features, the comparison of three different learning algorithms for recognizer design, and the performance enhancement with decision fusion. The paper concludes with the discussions of the experimental results and some of the future work.

Model-based design is a collection of practices in which a system model is at the center of the development process, from requirements definition and system design to implementation and testing. This approach provides a number of benefits such as reducing development time and cost, improving product quality, and generating a more reliable final product through the use of computer models for system verification and testing. Model-based design is particularly useful in automotive control applications where ease of calibration and reliability are critical parameters. A novel application of the model-based design approach is demonstrated by The Ohio State University (OSU) student team as part of the Challenge X advanced vehicle development competition. In 2008, the team participated in the final year of the competition with a highly refined hybrid-electric vehicle (HEV) that uses a through-the-road parallel architecture.

This paper demonstrates the benefit of using simulation and robust optimization for the problem of balancing vehicle noise, vibration, and ride performance over road impacts. The psychophysics associated with perception of vehicle performance on an impact is complex because the occupants encounter both tactile and audible stimuli. Tactile impact vibration has multiple dimensions, such as impact hardness and memory shake. Audible impact sound also affects occupant perception of the vehicle quality. This paper uses multiple approaches to produce the similar, robust, optimized tuning strategies for impact performance. A Design for Six Sigma (DFSS) project was established to help identify a balanced, optimized solution. The CAE simulations were combined with software tools such as iSIGHT and internally developed Kriging software to identify response surfaces and find optimal tuning.

In this article, the authors illustrate the benefits of axiomatic design (AD) for robust optimization and how to integrate axiomatic design into a total robust design process. Similar to traditional robust design, the purpose of axiomatic design is to improve the probability of a design in meeting its functional targets at early concept generation stage. However, axiomatic design is not a standalone method or tool and it needs to be integrated with other tools to be effective in a total robust development process. A total robust development process includes: system design, parameter design, tolerance design, and tolerance specifications [1]. The authors developed a step-by-step procedure for axiomatic design practices in industrial applications for consistent and efficient deliverables. The authors also integrated axiomatic design with the CAD/CAE/statistical/visualization tools and methods to enhance the efficiency of a total robust development process.

A DFSS study identified a new mechanism for clamp load loss in aluminum threads due to thermal cycling. In bolted joints tightened to yield, the difference in thermal expansion between the aluminum and steel threads can result in a loss of clamp load with each thermal cycle. This clamp load loss is significantly greater than the loss that can be explained by creep alone. A math model was created and used to conduct a robust analysis. This analysis led to an understanding of the design factors necessary to reduce the cyclic clamp load loss in the aluminum threads. This understanding was then used to create optimized design solutions that satisfy constraints common to powertrain applications. Estimations of clamp load loss due to thermal cycling from the math model will be presented. The estimates of the model will be compared to observed physical test data. A robust analysis, including S/N and mean effect summary will be presented.

In racetrack conditions, brake systems are subjected to extreme energy loads and energy load distributions. This can lead to very high friction surface temperatures, especially on the brake corner that operates, for a given track, with the most available traction and the highest energy loading. Individual brake corners can be stressed to the point of extreme fade and lining wear, and the resultant degradation in brake corner performance can affect the performance of the entire brake system, causing significant changes in pedal feel, brake balance, and brake lining life. It is therefore important in high performance brake system design to ensure favorable operating conditions for the selected brake corner components under the full range of conditions that the intended vehicle application will place them under. To address this task in an early design stage, it is helpful to use brake system modeling tools to analyze system performance.

At the early design stage it is easier to achieve impacts on the brake noise. However most noise analyses are applied later in the development stage when the design space is limited and changes are costly. Early noise analysis is seldom applied due to lack of credible inputs for the finite element modeling, the sensitive nature of the noise, and reservations on the noise event screening of the analysis. A high quality brake finite element model of good components’ and system representation is the necessary basis for credible early noise analysis. That usually requires the inputs from existing production hardware. On the other hand in vehicle braking the frequency contents and propensity of many noise cases are sensitive to minor component design modifications, environmental factors and hardware variations in mass production. Screening the noisy modes and their sensitivity levels helps confirm the major noisy event at the early design stage.

This paper presents the development of a transmission closed loop pressure control system. The objective of this system is to improve transmission pressure control accuracy by employing closed-loop technology. The control system design includes both feed forward and feedback control. The feed forward control algorithm continuously learns solenoid P-I characteristics. The closed loop feedback control has a conventional PID control with multi-level gain selections for each control channel, as well as different operating points. To further improve the system performance, Robust Optimization is carried out to determine the optimal set of control parameters and controller hardware design factors. The optimized design is verified via an L18 experiment on spin dynamometer. The design is also tested on vehicle.

The work presented in this paper outlines the development of a simulation model to aid in the design and development of a compliant sprocket for balancer drives. A design with dual-mass flywheel and a crank-mounted compliant chain sprocket greatly reduces interior noise levels due to chain meshing. However, experimental observations showed the compliant sprocket can enter into resonance and generate excessive vibration energy during startup. Special features are incorporated into the compliant sprocket design to absorb and dissipate this energy. Additional damper spring rate, high hysteresis and large motion angle that overlap the driving range may solve the problem during engine start-up period. This work develops a simulation model to help interpret the measured data and rank the effectiveness of the design alternatives. A Multibody dynamics system (MBS) model of the balancer chain drive has been developed, validated, and used to investigate the chain noise.