Sport Utility Vehicle Research Articles

The GTU: A New Realistic Generic Pickup Truck and SUV Model

<div class="section abstract"><div class="htmlview paragraph">Traditionally, ground vehicle aerodynamics has been researched with highly simplified models such as the Ahmed body and the SAE model. These models established and advanced the fundamental understanding of bluff body aerodynamics and have generated a large body of published data, however, their application to the development of passenger vehicles is limited by the highly idealized nature of their geometries. To date, limited data has been openly published on aerodynamic investigations of production vehicles, most likely due to the proprietary nature of production vehicle geometry. In 2012, Heft et al. introduced the realistic generic car model ‘DrivAer’ that better represents the flow physics associated with a typical production vehicle. The introduction of the DrivAer model has led to a broad set of published data for both experimental and computational investigations and has proven itself invaluable as a correlation and calibration tool of wind tunnels, the validation of computational fluid dynamics (CFD) codes and increasing the understanding of the fundamental flow physics around passenger vehicles.</div><div class="htmlview paragraph">Automotive sales trends in the United States, published by the Bureau of Economic Analysis in 2018, indicate that sales of Pickup Trucks (PUs) and Sports Utility Vehicles (SUVs) have increased over the past 10 years and are outselling sedans at a rate just over two to one. Compared to sedans, PU and SUV body styles pose additional aerodynamic challenges due to their complex wake structures. The introduction of a realistic generic PU and SUV model as an open access tool is expected to yield benefits to the wider community, equivalent to those of the DrivAer passenger vehicle. This paper introduces the Generic Truck Utility (GTU) as a realistic, generic PU truck and interchangeable SUV model. The paper will focus on the design and development of the GTU and will present a summary of preliminary experimental results of the GTU complemented by numerical simulations using iconCFD®, an open source based CFD solver.</div></div>

Modelling and control of vehicle integrated thermal management system of PEM fuel cell vehicle

An effective vehicle integrated thermal management (VITM) system is critical for the safe and efficient operation of proton exchange membrane fuel cell (PEMFC) vehicles. The objectives of this paper are to model the VITM system and develop control strategies for the VITM system of fuel cell vehicles (FCVs). To do that, the VITM system model, based on the heating principle of each key component and heat transfer theory, was developed in KULI. The VITM system includes 5 loops for a prototype of range extender sport utility vehicle (SUV), which is powered by a 36 kW PEMFC stack and an 11 kW h Li-ion battery. Then, three steady-state and two transient working conditions of FCVs were selected to simulate. The results showed that the temperatures of all components were controlled within the required ranges, indicating that the VITM system achieves relatively positive cooling capacity and satisfies the requirements of thermal management control effect. It showed that the developed VITM system could analyse the impact on one loop and the integrated impact on the whole vehicle when the thermal state of one or several components changes, which is useful to guide the VITM system design of the PEMFC vehicles.

Environmental and traffic assessment of adjusting Triple Highway Capacity Manual (HCM) factors at signalized intersections

Kuwait traffic networks has started to develop in the early 60’s. Since it is crucial to determine the parameters that present the local conditions in Kuwait, this study was developed to modify the passenger car equivalent (PCE) values at different signalized intersections in Kuwait and obtain the heavy-vehicle adjustment factor. The headway ratio method was utilized to determine the PCE values for different kinds of vehicles. 1. The PCE values were 1.14, 1.11, 1.26, 1.68 and 1.48 for sport utility vehicles (SUV), pickups, minibuses, trucks, and buses respectively. 2.The heavy vehicle adjustment factor was 0.891. Synchro simulation software was utilized to build different scenarios for improving an existing intersection and compare the network performance for each scenario. Two scenarios were chosen to be the best which are having five lanes with 2.4 m width for the first scenario and 2.7 m width for the second one. 3. Based on Synchro results, fuel consumption and pollutant emissions parameters were used to estimate the cost difference in the two best scenarios, and it was 10.71 and 13.23 Kuwaiti dinar (KD), respectively. Also, the percentage reduction of the emissions were 15.5% and 19.19%, respectively. The impact of adding an extra lane was noticed to be better compared with increasing the lane widths in a significant way. Additionally, it is a must to localize the parameters to represent the local conditions in Kuwait. The heavy-vehicle adjustment factor has an essential effect on the network performance which indicates that the PCE values should be determined accurately.

Fade and recovery characteristics of commercial disc brake friction materials: a case study

Friction materials are usually evaluated according to their friction performance at high temperatures, i.e. fade performance. In the present study, the vehicle under consideration is a sport utility vehicle. An experimental investigation is carried out to find out fade and recovery characteristics of four commercial disc brake friction materials using a four-wheeler inertia brake dynamometer. For these four grades naming is given i.e. FC1, FC2, FC3, and FC4. The Grade FC1 is without steel content. FC2 is with low steel content, FC3 is low steel content with organic brake friction material, and FC4 is non-asbestos organic friction material. SEM-EDX analysis is carried out for finding different elements and microstructural characterisation of brake friction material. Grade FC2 attained the highest temperature, and FC4 attained the lowest temperature during the fade test. Grades FC1 and FC4 show better recovery characteristics as compared to other grades.

The Influence of Road Geometry on Vehicle Rollover and Skidding.

This paper analyzes the influence of single and combined unfavorable road geometry on rollover and skidding risks of D-class mid-sized sport utility vehicles (SUVs) with front-wheel drive for roads with design speeds at 80 km/h. A closed-loop simulation model of human-vehicle-road interactions is established to examine the systematic influence of road geometry on vehicle rollover and skidding. The effects of different road geometry on rollover and skidding on SUVs are studied for pavement surface with good and poor friction when vehicles are in the action of steady state cornering. The rollover and skidding risks of the most unfavorable road segments are assessed. The critical wheel is defined by the threshold of skidding during curve negotiation. The results found that SUVs are not easy to rollover on the most unfavorable roads, regardless of good or poor friction of pavement surface. The safety margin of rollover is greater than that of skidding. The safety margin of skidding is minimal on poor friction roads. Therefore, for the sake of driving safety, it is not recommended to design the roads with these unfavorable road geometry combinations

Trends in life cycle greenhouse gas emissions of future light duty electric vehicles

The majority of previous studies examining life cycle greenhouse gas (LCGHG) emissions of battery electric vehicles (BEVs) have focused on efficiency-oriented vehicle designs with limited battery capacities. However, two dominant trends in the US BEV market make these studies increasingly obsolete: sales show significant increases in battery capacity and attendant range and are increasingly dominated by large luxury or high-performance vehicles. In addition, an era of new use and ownership models may mean significant changes to vehicle utilization, and the carbon intensity of electricity is expected to decrease. Thus, the question is whether these trends significantly alter our expectations of future BEV LCGHG emissions.To answer this question, three archetypal vehicle designs for the year 2025 along with scenarios for increased range and different use models are simulated in an LCGHG model: an efficiency-oriented compact vehicle; a high performance luxury sedan; and a luxury sport utility vehicle. While production emissions are less than 10% of LCGHG emissions for today’s gasoline vehicles, they account for about 40% for a BEV, and as much as two-thirds of a future BEV operated on a primarily renewable grid. Larger battery systems and low utilization do not outweigh expected reductions in emissions from electricity used for vehicle charging. These trends could be exacerbated by increasing BEV market shares for larger vehicles. However, larger battery systems could reduce per-mile emissions of BEVs in high mileage applications, like on-demand ride sharing or shared vehicle fleets, meaning that trends in use patterns may countervail those in BEV design.

Design and Testing of Fuzzy Logic Based Controller for Active Suspension System of a Quarter Car Model

In today’s scenario, due to increase in sales of Sports Utility Vehicles (SUV’s) more and more people are opting for off road drive. The main challenge is to improve the performance based on handling and comfort. Hence the conventional static spring and damper system are being modified to accommodate semi-active and active systems. In this paper to study the effectiveness of active suspension system, a quarter car model is developed and Fuzzy control strategy is proposed to reduce displacement of chassis. Hydraulic actuator is used to provide active control in the suspension system of the quarter car model. The fuzzy logic controller is interfaced with the hardware system by LabVIEW software. For connecting the hardware with LabVIEW software Arduino is used. The comparison of active and passive suspension system shows that the chassis displacement is decreased by 30% in case of active suspension system whereas the settling time decreases by 69%.

Hardware-in-the-Loop Test of an Open-Loop Fuzzy Control Method for Decoupled Electrohydraulic Antilock Braking System

To verify the functionality of an intelligent open-loop fuzzy-logic-based antilock braking system control method for four on-board motor drive electric sport utility vehicle, a hardware-in-the-loop experiment is conducted in this article. The experimental facility includes a novel decoupled electrohydraulic brake test bed characterized by highly nonlinear dynamics and time-varying behavior. It reproduces real pressure dynamics of the brake circuit allowing for simulation of various tire–road adhesions conditions and brake blending scenarios. To cope with degradation of antilock braking system performance induced by unexpected changing environmental conditions, such as road surface, the developed fuzzy control features a very simple yet effective and robust road surface recognition tool with estimation of the peak braking demands. Thus, the fuzzy logic serves as a controller and road surface estimator simultaneously allowing for complex mathematical modeling and feedback control avoidance not sacrificing safety system's performance. The results indicate that the control method manages highly nonlinear and time-variant dynamics of the brake system and offers significant feasibility for optimal slip control at regenerative braking, ensuring fuzzy control's potentiality for real-time application.

Plug-in electric vehicles in China and the USA: a technology and market comparison

As the top two plug-in electric vehicle (PEV) markets in the world, China and the United States of America (USA) have developed different market structures that are influenced by government policies, test procedures, customer acceptance, and vehicle performance. There are differences in PEV test procedures and vehicle class definitions as well. This paper quantifies such differences and compares PEV characteristics and markets in the two countries using actual data collected over several years. First, although China surpasses the USA in annual PEV production because of generous PEV policies and higher charging infrastructure availability, the USA has a higher PEV adoption rate per capita (2.3 versus 0.81 per 1000 people at the end of 2017). Second, the most popular vehicle classes are A00 battery electric vehicles (BEVs) in China but long-range mid-size BEVs in the USA. Moreover, China’s electric and plug-in hybrid sport utility vehicle market is growing quickly. Third, the electricity consumption rated under Chinese test procedures is 20%–40% lower than that rated under US procedures. The sales-weighted electricity consumption of an average BEV in China is 23% lower than that in the USA because of larger proportions of small and micro BEVs in China. Fourth, PEV battery cost in the two countries is currently close to $210–$220 kWh. Finally, China has higher numbers of charging infrastructure, and the ratio of PEVs to public chargers is 9.0 in China versus 17.9 in the USA at the end of 2018.

Vehicle dynamics: experimental analysis of sedan and sport utility vehicle

Sport utility vehicles (SUVs) have off-road features, including superior ground clearance, high driving position and towing capability. These features have increased SUV sales mainly in emerging markets. However, their high centres of gravity (CGs) can reduce the handling capability, safety, and comfort of this type of vehicle. Despite this consideration, the comfort and handling of SUVs have not been explored in the literature. Hence, in this study, an SUV and a sedan platform are quantitatively compared concerning static construction parameters such as mass, CG, and suspension characteristics. Measuring their vertical accelerations and rotation movements performs a second evaluation. Based on the results, it is verified that the roll behaviour of the SUV is similar to the medium sedan, but it is necessary to highlight the differences in their CG heights and damping ratios. The lower damping ratio available in the SUV suspension brings greater vertical acceleration and pitch movement.

Modelling traumatic brain injury in pedestrian involved in backover collisions

Backover collisions causing Traumatic Brain Injuries (TBIs) are underreported, and its severity may have been overlooked and underestimated. We conducted a series of pedestrian impact simulations involving backover collisions with a reversing vehicle, at a low speed of 10 km/h, to determine the risk of sustaining severe TBIs. Our modelling studies revealed a significant risk despite the 'moderate' impact configuration applied. By systematically performing injury analyses based on selected mechanical parameters, we found that TBI risk involved in primary head strike with a striking vehicle was almost negligible because of the low-speed collision, but significant injuries result from ground impact. Our study also demonstrated that pedestrians are potentially at a greater risk for TBI when struck by a Sport Utility Vehicle (SUV) than a conventional sedan, because the impact energy would be effectively transmitted from the SUV via its flat rear surface with a steep angle.

Vehicle dynamics: experimental analysis of sedan and sport utility vehicle

Vehicle dynamics: experimental analysis of sedan and sport utility vehicle

Method for evaluating vehicular design concepts transference

Product design concepts are the heart and soul of product design. During the design process, designers often face the challenge of how to most effectively transfer their design concepts during product modelling. If users are unable to clearly perceive the meaning of a product's design, then the product is less desirable. Therefore, the 'resonance' between product design concepts and the product's user is an important indicator of the ultimate success (or lack thereof) of a product. That is, success relies on whether users can understand and accept the concept of the design. In this paper, we performed two experiments to explore whether the explicit and implicit attitudes of users towards vehicular design concepts were consistent. A case study was conducted to investigate this issue using a sports utility vehicle. We can conclude that a method utilising combined perception matching, eye tracking, and explicit/implicit attitude testing can help designers evaluate the effect of design concept transference.

Multi-criteria selection methods (MCDM) for lower bumper stiffener material change in a Sports Utility Vehicle with CAE simulation

This article describes the steps to replace the lower bumper stiffener material of a sport utility vehicle. It was taken as the main characteristics to obtain the behaviour principles as the lower bumper stiffener. A static structural simulation was developed according to the regulation of physical trials of the EuroNCAP. Three multi-criteria selection methods called TOPSIS, VIKOR and ENTROPY were applied. Polylactic acid was determined as the optimal material. A dynamic simulation between of the contact of the leg form impactor and pedestrian protection system, at a speed of 40 km/h was performed. The simulation evaluates the acceleration of the tibia, equivalent strain of Von Misses and deformation in the three nodes of the lower bumper stiffener. It was determined that the optimal material is the PLA, where it is appreciated that the main factors to consider for the decision making is the acceleration and the nodal deformation of the dynamic simulation.

Research on a Novel Vehicle Rollover Risk Warning Algorithm Based on Support Vector Machine Model

A novel vehicle rollover warning algorithm based on support vector machine (SVM) empirical model is proposed to improve the real-time of un-tripped rollover warning algorithm and accuracy of dynamic rollover warning. Considering the nonlinear characteristic of driver-vehicle-road interaction and the uncertainty of modeling, the traditional deterministic methods cannot meet the requirements of accurate vehicle rollover warning modeling. The probability method considering issues of uncertainty is applied to design vehicle dynamic rollover warning algorithm. The SVM empirical model considers the uncertainties of the driver-vehicle-road system and the real variability of the parameters, provides an explicit function of vehicle rollover safety limit and its gradient, and utilizes the hypersurface visualization boundary to define the rollover safety area and the unsafe area. Targeting on sport utility vehicle under the condition of high-speed emergency obstacle avoidance, simulations are carried out to verify the proposed vehicle rollover warning algorithm based on SVM empirical model and of the simulation results show that the proposed algorithm has accurate warning and good real-time performance. It can effectively improve the warning accuracy of vehicle dynamic rollover, reduce the interference of nonlinear and uncertainty, and significantly improve the active safety performance with vehicle rollover prevention.

Connection between rear-end extensions and yaw response of a passenger vehicle

This paper aims to investigate the sensitivity of the rear-end design to the yaw response of a passenger vehicle. To accomplish this, rear-end extensions are attached to the base perimeter of a sport utility vehicle (SUV). The intention of the extensions is to improve and to smooth out the pressure recovery such that a more stable wake is created. The extensions facilitate the implementation of configuration changes with respect to design, inclination angle and length. To control the separation conditions of the flow entering the near-wake, two different designs are studied. The yaw response is analysed through the global forces and flow field measurements presented as surface pressure distributions and wake plane measurements of local drag. The results show that the rear-end can be designed as to control the yaw response so the aerodynamic drag is minimised and passenger vehicle stability is maintained.

Connection between rear-end extensions and yaw response of a passenger vehicle

This paper aims to investigate the sensitivity of the rear-end design to the yaw response of a passenger vehicle. To accomplish this, rear-end extensions are attached to the base perimeter of a sport utility vehicle (SUV). The intention of the extensions is to improve and to smooth out the pressure recovery such that a more stable wake is created. The extensions facilitate the implementation of configuration changes with respect to design, inclination angle and length. To control the separation conditions of the flow entering the near-wake, two different designs are studied. The yaw response is analysed through the global forces and flow field measurements presented as surface pressure distributions and wake plane measurements of local drag. The results show that the rear-end can be designed as to control the yaw response so the aerodynamic drag is minimised and passenger vehicle stability is maintained.

Customer Analysis of Mid-Range Sport Utility Vehicle in India

Customer Analysis of Mid-Range Sport Utility Vehicle in India

Longitudinal Vehicle Dynamics: A Comparison of Physical and Data-Driven Models Under Large-Scale Real-World Driving Conditions

Mathematical models of vehicle dynamics will form essential components of future autonomous vehicles. They may be used within inverse or forward control loops, or within predictive learning systems. Often, nonlinear physical models are used in this context, which, though conceptually simple (especially for decoupled, longitudinal dynamics), may be computationally costly to parameterise and also inaccurate if they omit vehicle-specific dynamics. In this study we sought to determine the relative merits of a commonly used nonlinear physical model of vehicle dynamics versus data-driven models in large-scale real-world driving conditions. To this end, we compared the performance of a standard nonlinear physical model with a linear state-space model and a neural network model. The large-scale experimental data was obtained from two vehicles; a Lancia Delta car and a Jeep Renegade sport utility vehicle. The vehicles were driven on regular, public roads, during normal human driving, across a range of road gradients. Both data-driven models outperformed the physical model. The neural network model performed best for both vehicles; the state-space model performed almost as well as the neural network for the Lancia Delta, but fell short for the Jeep Renegade whose dynamics were more strongly nonlinear. Our results suggest that the linear data-driven model gives a good trade-off in accuracy and simplicity, whilst the neural network model is most accurate and is extensible to more nonlinear operating conditions, and finally that the widely used physical model may not be the best choice for control design.

Non-Contact vehicle Weigh-in-Motion using computer vision

Heavy vehicles must be closely monitored to prevent fatigue-induced deterioration and critical fractures to transportation infrastructure. This paper introduces an innovative computer vision-based non-contact vehicle weigh-in-motion method and presents a proof-of-concept study. The method is based on simple physics that tire-roadway contact force equals the contact pressure multiplied by the contact area. The area can be estimated by measuring tire deformation parameters such as tire-roadway contact length and tire vertical deflection using computer vision, while tire pressure can be streamed from on-board sensors. To demonstrate the feasibility of this method, a computer vision system was developed and experiments were conducted involving empty and fully loaded concrete trucks and a sport utility vehicle. Results show high accuracy of vehicle weight estimation, demonstrating the potential of this computer vision-based method as a non-contact means for weighing vehicles in motion.