Lateral Stability Analysis for Car-Trailer Combinations

This paper presents a parametric study of linear lateral stability of a car-trailer (CT) combination in order to examine the fidelity, complexity, and applicability for control algorithm development for CT systems. Using MATLAB software, a linear yaw-roll model with 5 degrees of freedom (DOF) is developed to represent the CT combination. In the case of linear stability analysis, a parametric study was carried out using eigenvalue analysis based on a linear yaw-roll CT model with varying parameters. Built upon the linear stability analysis, an active trailer differential braking (ATDB) controller was designed for the CT system using the linear quadratic regulator (LQR) technique. The simulation study presented in this paper shows the effectiveness of the proposed LQR control design and the influence of different trailer parameters.

Design of an Efficient Catalytic Converter Using CFD Techniques

This study presents the design of an efficient catalytic converter with increased flow rate and minimum pressure drop using Computational Fluid Dynamics (CFD) techniques. Automobile engines produce undesirable emissions during the combustion process, such as NOx, CO, and unburned hydrocarbons. In addition to these harmful gases, particulate matter, such as lead and soot, is created. As a countermeasure, automobiles are equipped with catalytic converters, which are designed to play a vital role in eradicating emissions. However, due to the catalyst and filler materials found inside the converters, an increase in backpressure develops which leads to an increase in fuel consumption. The gas must pass through a low-porosity substrate to increase the reaction rate, which was simulated using parametric geometry. In this study, parametric simulations of the fluid flow were conducted, utilizing CFD techniques, to determine the optimum parameters that would create a minimal pressure drop while maintaining a high chemical reaction rate.

Investigation of Heavy Truck Restraint System Effectiveness Through Finite Element Computer Simulations in Frontal Crashes

Computer finite element simulations play an important role in reducing the cost and time taken for prediction of a crash scenario. While interior crash protection has received adequate attention for automobiles, very little is known for commercial vehicle such as heavy trucks. The understanding of injury types for heavy trucks occupants in relation to different crash scenarios would help mitigation of the injury severity. Finite element computer models of the heavy truck cabin structure, interior cabin components, anthropomorphic test device (ATD) (also called dummy) and passive restraint systems were developed and assembled to simulate head-on crash of a heavy truck into a rigid barrier. The researchers developed a computer simulation parametric evaluation with respect to specific seat belt restraint system parameters for a speed impact of 56.3 km/h (35 mph). Restraint parameter variations within this research study are seat belt load limiting characteristics, inclusion of seat belt pretensioner, and variation of seat belt D-ring location. Additionally an airbag was included to investigate another restraint system. For each simulated impact characteristic and restraint system variation, the occupant kinematics were observed and occupant risks were assessed. Within the approximations and assumptions included in this study, the results presented in this paper should be considered as preliminary guidance on the effectiveness of the use of seat belt as occupant injury mitigation system.

A Pneumatic Multi-Dome Active Energy Harvesting System

When traveling through heavy traffic, vehicles lose a large amount of their kinetic energy. These losses can be attributed to various sources such as the roll friction of the tires against the road pavement. According to the Federal Highway Administration, there are an average of 304,000 cars a day travelling on the US-75 near the Dallas Fort Worth Arlington area in Texas. With so much available energy being wasted, it is essential to find a different way to harness losses so that they can be recycled. The purpose of this research project is to design a system that will harvest some of this lost energy using a set of pneumatic cylinders built into the road. The cylinders will have a dome shape that extends slightly above the surface of the road. As cars pass over this dome the cylinder will retract and compressed air will be sent through a pneumatic system, to an air tank where it is stored. The energy generated by the air stored in the cylinder can be used to drive a pneumatic motor that can turn a generator. The generator could then be used for multiple purposes such as: charge a battery, power a toll booth or other near highway structures. The compressed air stored in the tank may be used for other applications. This is useful due to the fact that almost every industry from the medical industry to the food industry use compressed air to power their pneumatic tools. The pneumatic cylinder will be used in areas of high traffic such as when a car approaches a toll booth, or entrances and exits of multi-level parking garages. The pneumatic cylinder and the associated air flow system using a CAD and a pneumatic software. The behavior of the system could then be tested and be better understood. After the initial simulation testing, a physical prototype has been built in order to gather practical data that can be compared to the simulations. Based on the gathered data on the prototype an assembly of numerous road rumbles can be built and tested on real streets. It is expected that a high pressure will be built in the tank using the prototype. Once pressure is built in the system data will be generated using various instruments, which will show pressure versus time, and pressure versus number of strokes so that the system can be better understood during the testing period. This data will then be used to determine the efficiency, and viability of the proposed system in generating compressed air as a form energy.

A Virtual Modelling of a Hybrid Road Tractor for Freight Delivery

The market of the hybrid electric vehicles has been increasing for several years. Different commercial EV and PHEV solutions are available for passenger cars and light vehicles for freight deliveries. However, the market of heavy trucks still regards traditional ICE vehicles powered by diesel oil fuel. The recent interest for electric solutions have been pushing the development of the hybrid solutions, but only micro-hybrid systems are considered feasible for heavy truck applications. The proposed research aims to define a methodological approach with a virtual model in order to simulate the behavior of a hybrid heavy truck. The scope of this research is the feasibility analysis of a retrofit hybrid heavy truck. A real driving cycle has been used in order to obtain reliable results in terms of cost, energy consumption and gas emission. The layout of the hybrid system has been proposed as well as the sizing of battery and electric motor. A commercial tool has been used for the vehicle modelling and simulation. As a test case, an 18-ton truck has been analyzed with a 10-liter diesel engine. Firstly, the simulation of the diesel truck has been reproduced considering the real driving cycle data. Secondly, the simulation activity has been focused on the evaluation of the hybrid system behavior by investigating different battery sizes with the same boundary conditions related to the real driving cycle.

Analysis of Vehicle Lateral Response During Regenerative Braking in a Turn

Regenerative braking is applied only at the driven wheels in electric and hybrid vehicles. The presence of brake force only at the driven wheels reduces the lateral traction limit of the corresponding tires. This impacts the vehicle lateral response, particularly while applying the regenerative brake in a turn. In this paper, a detailed study was made on the impact of regenerative brake on the vehicle lateral response in front wheel drive and rear wheel drive configurations on dry and wet asphalt road surfaces. Simulations were done considering a typical set of vehicle parameters with the IPG CarMaker® software for different drive conditions and braking configurations along the same reference track. The steering wheel angle, yaw rate, lateral acceleration, vehicle slip angle, and tire forces were obtained. Further, they were compared against the conventional all wheel friction brake configuration. The regenerative braking configuration that had the most impact on vehicle lateral response was analyzed and response variations were quantified.

Optimized Modular Design for Energy Efficiency: The Case of an Innovative Electric Hybrid Vehicle Design

Modular Design has made an important contribution to the industrial evolution, increase of quality of products and goods and to economic development. It has produced an important evolution in design (technical modularity), in the organization of production and of companies. It allowed going beyond vertical integration, by fostering vertical specialization in both manufacturing and innovation. Several authors are appointing important question on the modular approach. They move observations of different nature concluding that the enthusiasm for modularity has gone too far. One of the critical positions sustains that modular design has imposed technical choices that conflicts with energy efficiency in vehicle design such as a gradual increase of weight over time and the consequent reduction of potential gains in terms of energy consumption and environmental footprint of vehicles. This paper agrees with some arguments of the revisionist literature in cautioning against errors that can be produced by a pervasive modularity. But it moves from an energetic analysis and has not the objective of defining an alternative theory. More modestly, it aims to present a possible way for coupling modular design with energy optimization in the case of an electric vehicle. The initial inspiration can be of this case study is Bejan’s preliminary modular definition of constructal optimization, which can fit perfectly with industrial modular design. Even if this modular optimization does not have the ambition of defining the best possible solution to a complex design problem, such as Multidisciplinary Design Optimization has, it allows defining configuration that can simply evolve over time by mean of a step by step optimization of the critical components that influences the behavior of a complex industrial system. It reveals then to be applicable to the concept of vehicle platform that is today widely in use. The specific test case is the design of an electric city vehicle which has been optimized by a step applying this modular optimization approach. This paper has also a romantic value because it ha taken the move from the emotion that has been caused by the stop to the production of an extraordinary myth, such as Land Rover Defender. 70 years of production without important changes means that Defender has been not only the most successful British vehicle, but also that it has been a fundamental part of our way of living. This extraordinary longevity is an extraordinary technical and cultural heritage to our time. This decision forces the authors to try to analyze the conceptual modular design of a vehicle that can compete with Defender in terms of use and performances. Results have been surprising demonstrating that the use of industrial grade components and their accurate choice will allow defining new vehicle platforms that can radically improve energy efficiency of vehicles.

A Base Study to Investigate MASH Conservativeness of Occupant Risk Evaluation

The Manual for Assessing Safety Hardware (MASH) defines crash tests to assess the impact performance of highway safety features in frontal and oblique impact events. Within MASH, the risk of injury to the occupant is assessed based on a “flail-space” model that estimates the average deceleration that an unrestrained occupant would experience when contacting the vehicle interior in a MASH crash test and uses the parameter as a surrogate for injury risk. MASH occupant risk criteria, however, are considered conservative in their nature, due to the fact that they are based on unrestrained occupant accelerations. Therefore, there is potential for increasing the maximum limits dictated in MASH for occupant risk evaluation. A frontal full-scale vehicle impact was performed with inclusion of an instrumented anthropomorphic test device (ATD). The scope of this study was to investigate the performance of the Flail Space Model in a full scale crash test compared to the instrumented ATD recorded forces which can more accurately predict the occupant response during a collision event. Results obtained through this research will be considered for better correlation between vehicle accelerations and occupant injury. This becomes extremely important for designing and evaluating barrier systems that must fit within geometrical site constraints, which do not provide adequate length to redirect test vehicles according to MASH conservative evaluation criteria.

Performance Summary of Continuous Mining Machine Proximity Detection Systems

Since 1984, remote controlled continuous mining machines (CMM) have caused 40 crushing and pinning fatalities in the United States. Due to limited space in the underground environment and visibility needs, CMM operators typically work close to the machine which exposes them to the danger of being struck or pinned by it. Because of these fatalities, the Mine Safety and Health Administration (MSHA) has published a rule requiring proximity detection systems (PDSs) on all CMMs except for full-face machines. To test PDS performance, researchers at the National Institute for Occupational Safety and Health (NIOSH) conducted a series of field tests in underground coal mines throughout the United States on CMMs equipped with PDSs. The field tests collected data under a variety of conditions to evaluate the warning and shutdown zone performance of these systems. A baseline test condition was measured when the machine was operating in non-mining mode. Three additional conditions discussed in this paper include testing of the PDS while the machine was operating in mining mode, examining the possibility of parasitic coupling to the trailing cable, and examining the effects of the presence of a shuttle car. The results of this study indicate that the average warning and stop zones vary minimally between non-mining mode and trailing cable influence measurements, as well as between the mining mode and shuttle car presence tests. A majority of the measurements for warning and stop zones showed repeatability within +/− 5 inches (12.7 cm). Additionally, parasitic coupling to the trailing cable was not experienced during this field testing. However, these results show that the range of stop zone measurements varied by 4.7 ft on average and as much as 11.7 ft in different field sites. This is most likely due to individual preferences by operators during installation when the warning and stop zone distances are set. While a PDS should effectively stop a CMM when an operator gets too close to the machine, the large variations between field test measurements indicate that there is a wide variation of performance established during system installation.

Energy Absorption Optimization of GFRP Laminate by Considering Inner-Lamina Damage Model With Parameter Identification

In order to improve the simulation accuracy of composite tube crush by finite element method, a nonlinear progressive damage model predicting the progressive inner-lamina damage of laminates is implemented. Each element of FEM is defined by the model. All parameters in this model were identified according to the published test data. The longitudinal crush was simulated by the solver of ABAQUS /explicit using the nonlinear progressive model. The result shows that the failure form pattern, peak force and energy absorption fit well with the published experimental ones. The robust optimization based on Six sigma technology and probability distribution of design variables is carried out to obtain an improved energy absorption property instead of deterministic optimization. This method can obtain an optimal composite tube with stable high energy absorption capability in a practical manufacture process.