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Training / Education

ADAS Application Automatic Emergency Braking

2022-09-29
Active Safety, Advanced Driver Assistance Systems (ADAS) are now being introduced to the marketplace as they serve as key enablers for anticipated autonomous driving systems. Automatic Emergency Braking (AEB) is one ADAS application which is either in the marketplace presently or under development as nearly all automakers have pledged to offer this technology by the year 2022. This one-day course is designed to provide an overview of the typical ADAS AEB system from multiple perspectives.
Training / Education

Vehicle Crash Reconstruction Principles and Technology

2022-05-10
Crash reconstruction is a scientific process that utilizes principles of physics and empirical data to analyze the physical, electronic, video, audio, and testimonial evidence from a crash to determine how and why the crash occurred. This course will introduce this reconstruction process as it gets applied to various crash types - in-line and intersection collisions, pedestrian collisions, motorcycle crashes, rollover crashes, and heavy truck crashes. Methods of evidence documentation will be covered. Analysis methods will also be presented for electronic data from event data recorders and for video.
Technical Paper

Comparing stress gradient and other concepts for fatigue analysis of notched components

2022-03-29
2022-01-0252
Nowadays simulation of the fatigue life is an essential part of the development of components in the automotive and machinery industry. Weak points can be identified fast and reliable with respect to stiffness, strength and lightweight. A pure virtual optimization of the design can be performed without the need of prototypes. Only for the production release a final test is necessary. A lot of parameters influence the fatigue life as the local stress, material, surface roughness, size of the component, temperature etc. Notches have the strongest impact on fatigue life, depending on radius and shape. Stresses at the notch base are increased because the load flow is forced through a reduced cross section, or changes its direction around an inwardly curved edge. But notches cause not only an increase of the local stress. Also, the local fatigue strength is increased because of a support effect from the neighboring areas, where the stress is already reduced.
Technical Paper

The investigation of a contact and element-based approach for Cohesive zone modelling in the simulation of Delamination propagation

2022-03-29
2022-01-0259
The CAE industry always moves towards new ways to improve the productivity, efficiency and to reduce the solution times. Conventional method of Cohesive Zone Modelling has drawback of higher computation and modelling time. Due to this problem, sometimes Engineers need to avoid simulations and rely only on some sort of approximation of crack from previous designs. This approximation can lead to either product failure or overdesign of the product. A new approach is discussed in this paper to simulate crack initiation and propagation with Cohesive Zone Modelling. Conventional method uses Cohesive zone modelling with Hex or Penta elements by assigning material with cohesive properties, which increases computation and modelling time. The new approach models Cohesive zone as contact between two bodies, thus eliminating the need to use cohesive elements which will essentially reduce the computation time as well as modelling time.
Technical Paper

Active brake wheel cylinder pressure control based on integrated electro-hydraulic brake system

2022-03-29
2022-01-0293
With the development of automobile industry, the requirements of quick response, high performance are put forward for the braking system. Since the traditional braking system cannot achieve these, the international brake parts manufacturers put forward an integrated electronic braking system -the 1-Box. It can realize active braking through the servo motor. In addition, by controlling the pressure of servo cylinder and working with solenoid valves, the wheel cylinder pressure can be controlled. However, it has some problems, such as hydraulic hysteresis disturbance and complex friction obstruction, which cause obstacles to the accurate control of wheel cylinder pressure. In this paper, the active brake pressure control strategy of wheel cylinders is designed based on 1-Box. First, introduce the configuration and the working principle of wheel cylinder pressure control; Next, design the servo cylinder active brake pressure control strategy composed of servo ring and pressure ring.
Technical Paper

Hierarchical Vehicle Stability Control Strategy Based on Unscented Kalman Filter Estimation

2022-03-29
2022-01-0294
High-speed vehicle is prone to instability under bad road conditions, causing many safety accidents such as tail-flicking and overturning. Stability control could assist vehicle to drive safely and stably by adjusting the additional yaw moment. However, most of the existing stability control strategies directly invoke the information of the sideslip angle of the centroid that is difficult to obtain on the vehicle, and carry out complex controller design, which deviates from the actual application. In order to achieve a complete set of stability control architecture oriented to practical applications, this paper designs a hierarchical vehicle stability control strategy based on differential braking and state estimation technology.
Technical Paper

A Review of Current Understanding of the Underlying Physics Governing the Interaction, Ignition and Combustion Dynamics of Multiple-injections in Diesel Engines

2022-03-29
2022-01-0445
This work is intended to be a comprehensive technical review of existing literature and a synthesis of current understanding of the governing physics behind the interaction of multiple fuel injectio ns, ignition and combustion behavior of multiple-injections in diesel engines. Multiple-injection is a widely adopted operating strategy applied in modern compression-ignition engines, which involves various combinations of small pre-injections and post-injections of fuel before and after the main injection and splitting the main injection into multiple smaller injections. This strategy has been conclusively shown to improve fuel economy in diesel engines while achieving simultaneous NOx, soot, and combustion noise reduction in addition to a reduction in the emissions of unburned hydrocarbons and CO by preventing fuel wetting and flame quenching at the piston wall.
Technical Paper

Modeling the Effects of Drop Impingement Frequency on Heated Walls at Engine Conditions

2022-03-29
2022-01-0508
Understanding the fundamental details of drop/wall interactions is important to improving engine performance. Most of the drop-wall interactions studies are based on the impact of a single drop on the wall. To accurately mimic and model the real engine conditions, it is necessary to characterize spray/wall interactions with different impingement frequencies at a wide range of wall temperatures. In this study, a numerical method, based on Smoothed Particle Hydrodynamics (SPH), is used to simulate consecutive droplet impacts on a heated wall both below and above Leidenfrost temperature. Impact regimes are identified for various impact conditions by analyzing the time evolution of the post-impingement process of n-heptane drops at different impingement frequencies and wall surface temperatures. At low temperature, crown propagation and merging are dominant at low K-number whereas at high K-number there is significant splashing with the traces of liquid film on the surface.
Technical Paper

Managing Trust along the CAN Bus

2022-03-29
2022-01-0119
Multiple approaches have been created to enhance intra-vehicle communications security over the past three decades since the introduction of CAN. The twin pair differential-mode communications bus is tremendously robust in the face of interference, yet physical access to the bus offers a variety of potential attack vectors whereby false messages and/or denial of service are easy to achieve. This paper seeks to evaluate extensions of a common-mode watermark-based authentication technique recently developed to improve authentication on the CAN bus by considering the watermark as a side-channel communications means for high value information. We also describe a variety of higher layer algorithms, with benefits and pitfalls, for employing the watermark as a physical-layer firewall. All of these results are backed by a software-defined radio (SDR) based hardware testbed.
Technical Paper

Visualization of Frequency Response Using Nyquist Plots

2022-03-29
2022-01-0753
Nyquist plots are a classical means to visualize a complex vibration frequency response function. By graphing the real and imaginary parts of the response, the dynamic behavior in the vicinity of resonances is emphasized. This allows insight into how modes are coupling, and also provides a means to separate the modes. Mathematical models such as Nyquist analysis are often embedded in frequency analysis hardware. While this speeds data collection, it also removes this visually intuitive tool from the engineer’s consciousness. The purpose of this paper is to review the fundamentals of Nyquist plots and their application to structural vibration. The behavior of a single degree of freedom system will be shown to be well described by a circle on its Nyquist plot. This observation allows simple visual examination of the response of a continuous system, and the determination of quantities such as uncoupled natural frequencies, modal damping factors, and uncoupled modes shapes.
Technical Paper

Rule-based Power Management Strategy of Electric-Hydraulic Hybrid Vehicles: Case Study of A Class 8 Heavy-Duty Truck

2022-03-29
2022-01-0736
Mobility in the automotive and transportation sector has been experiencing a period of unprecedented evolution. A growing need for efficient, clean and safe mobility has made a strong momentum toward sustainable technologies in this sector. Toward this end, battery electric vehicles have drawn keen interest and the market share is expected to grow significantly in the coming years, especially in light-duty applications such as passenger cars. Although battery electric vehicles feature high performance and zero emissions characteristics, economic and technical issues such as high battery cost, a short driving range, and limited infrastructure should be tackled. In particular, the low power density of battery electric vehicles limits their broad adoption in heavy-duty applications such as class 8 long haul trucks due to a size and weight of battery.
Technical Paper

How to Get Work From A Variable-inertia Flywheel

2022-03-29
2022-01-0640
HOW TO GET WORK FROM A VARIABLE-INERTIA FLYWHEEL By: James T. Gramling A variable-inertia flywheel (VIF) uses a spinning mass (flyweight-FW) that is movable perpendicular to the axis of rotation (AR). This VIF can produce a torque as the flyweight is shifted – a positive torque if shifted towards the AR and a negative torque if shifted away from the AR. This is because of the conservation of momentum law. The work required to shift the FW is exactly equal to work produced by the VIF. The work produced (+ or-) will accelerate or decelerate the VIF and any inertial load connected to it depending on the movement of the FW. This phenomenon has not found many vehicular applications, however, if two counter-rotating VIF’s are connected to a differential and the output is connected to the drive-line of a vehicle, the inertia of both VIF’s can be used to accelerate and decelerate a vehicle, thus providing regenerative braking.
Technical Paper

Development of a Generalized Model to Predict Efficiency of Electrified Power Transmission Considering Optimal Driving Efficiency

2022-03-29
2022-01-0641
The expansion of electrified powertrain over the past decade due to strict fuel efficiency regulations has led to the development of various powertrain systems. While operating the engine at high efficiency using a multi-speed gearbox is a feature of existing powertrain system development, recent trends are being developed to improve system operation efficiency based on a multi-power source configured by mixing an engine and a motor in a simple gearbox. This situation makes it necessary to analyze the overall system efficiency to compare the competitiveness of each system from the early stages of powertrain system development. The prediction of powertrain system efficiency is a process to understand how the system is composed and what strategy can be used for the system in driving cycle.
Technical Paper

A Work in Synthesizing Planetary Gear Trains for Plug-in Hybrid Electrical Powertrain Systems for Automotive Vehicles

2022-03-29
2022-01-0654
Planetary gear trains (PGT) are widely used in automatic transmissions (AT), hybrid electric powertrains (HEP) and plug-in hybrid electrical powertrains (PHEP) for automotive vehicles. Plenty PGTs have been developed by the industry throughout the history of automotive vehicles. To name few which includes 6, 7, 8, 9 or 10 speeds automatic transmissions (AT) for internal combustion engine (ICE) power train systems; PGTs with two electrical machines (EM) and an ICE for single mode or multi-mode HEP systems; PGTs with single EM and an ICE for PHEP systems. Facing the new competitive challenges in motor vehicle electrification, synthesizing the simplest PGTs for PHEP become an important task. The work reported in this article is a such effort which results in much simpler, if not simplest, PGT designs for PHEPs as well as for ATs. The methodology of the synthesis works, and the details of the results will be reported.
Technical Paper

Mobility Boundaries for the Wheel Normal Reaction

2022-03-29
2022-01-0360
When a vehicle moves over uneven ground, motion of the sprung and unsprung masses causes dynamic shifting in the load transmitted to the ground, making the normal reaction in the tire-soil patch a continuously changing wheel parameter that may affect vehicle performance. At high loads, sinkage of the wheel can become high as the wheel digs into the soil. At low loads, the wheel can have difficulty acquiring sufficient traction. Additionally, steerability of the wheel can be diminished at very low loads. Controlling the damping forces in the suspension that is usually used to improve ride quality and stabilize motion of the sprung mass can result in an increase in the dynamic variation of the wheel normal reaction and cause vehicle performance deterioration. In this paper, a method is developed to establish boundary constraints on the dynamic normal reaction to maintain reasonable tire-terrain mobility characteristics.
Technical Paper

Adaptive Cycle Engines: Results with 2nd Generation Combustion Model

2022-03-29
2022-01-0421
A more accurate combustion model, based on Fluent simulations including the effect of flame stretching and extinction, has been added to cycle and road simulations of an Adaptive Cycle Engine (ACE), where compressions and expansions do not follow a predefined sequence. Also, engine speed data from the Argonne Downloadable Dynamometer Database is used in the road simulations in lieu of the original constant-speed model. Results show a drop in predicted steady-state brake efficiency around 5% relative to the model using a standard Wiebe function for heat release rate, but peak bmep rises over 20%. Performance on road cycles is not greatly affected by the delayed combustion since the relationship between expansion mass and work is largely unchanged. Even with the refined model, ACE-equipped vehicles remain competitive with electric powertrains in pre-tax cost and overall emissions.
Technical Paper

Research on Brake Comfort Based on Brake-by-Wire System Control

2022-03-29
2022-01-0912
The vehicle will produce certain shock and vibration during the braking process, which will affect the driving experience of the driver. Aiming at the problems of pitch vibration, longitudinal vibration and shock during the braking process, this paper proposes a planning and following control method for target longitudinal acceleration in post-braking phase, and designs control trigger strategies. Target longitudinal acceleration planning takes minimizing longitudinal shock as the design goal. The following control takes the brake pressure as the control object, and adopts the "feedforward +PID feedback" method to follow the target longitudinal acceleration. Besides, considering the safety of braking process, the trigger condition of control is designed which utilizes BP neural network method to judge whether the control has to be triggered. Based on Simulink software, the simulation model of straight-line braking is established.
Technical Paper

Approaches for Simulation Model Reuse in Systems Design — A Review

2022-03-29
2022-01-0355
In this paper, we review the literature related to the reuse of computer-based simulation models in the context of systems design. Models are used to capture aspects of existing or envisioned systems and are simulated to predict the behavior of these systems. However, developing such models from scratch requires significant time and effort. Researchers have recognized that the time and effort can be reduced if existing models or model components are reused, leading to the study of model reusability. In this paper, we review the tasks necessary to retrieve and reuse model components from repositories, and to prepare new models and model components such that they are more amenable for future reuse. Model reuse can be significantly enhanced by carefully characterizing the model, and capturing its meaning and intent so that potential users can determine whether the model meets their needs.
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