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Suspension systems
Published in M.J. Nunney, Light and Heavy Vehicle Technology, 2007
As mentioned earlier, variable-mass air suspension systems for modern cars utilize electronic control systems as a basis for their operation (Figure 23.51). Such systems may then be extended to recognize an increased number of operating variables and, in some applications, include control over adaptive shock dampers (Section 23.6). Sensors may therefore be installed that not only detect and, if necessary, restore correct standing height of the car by signalling an increase or a decrease in air pressure for the springs, but also can take into account dynamic considerations. For example, an input from a road speed sensor can signal the trim height of the car to be varied automatically according to its speed. This feature is sometimes known as ‘speed levelling’ and confers the following advantages: On rough road surfaces the car can be raised to provide increased ground clearance.With increasing speed on normal road surfaces the car can be lowered. This enhances stability by reducing the height of its centre of gravity.From consideration of (2) the aerodynamic drag or Cd value of the car is reduced to improve fuel consumption (Section 30.7).
The Power of Shape
Published in Patrick Hossay, Automotive Innovation, 2019
The effect on lift can be complicated. Potentially, reducing the ground clearance can slow the air under the car, increasing the pressure difference between the top and bottom of the car, and so increase the overall lift of the car. With increasing ground clearance, the speed under the car is closer to the speed over the car, reducing overall lift effect, though Newtonian lift on the front of the underbody can increase, and certainly overall handling is impacted by the raised center of gravity. A diffuser at the rear of the car can help manage and shape these dynamics and control lift. But before we get to that, we need to discuss a prerequisite for the underbody diffuser: cleaner underbody airflow.
Suspension System
Published in G. K. Awari, V. S. Kumbhar, R. B. Tirpude, Automotive Systems, 2021
G. K. Awari, V. S. Kumbhar, R. B. Tirpude
Road clearance is essential when the vehicle travels on a rough road; the rigid axle suspension supports to maintain constant ground clearance in both the loading and unloading conditions and also when the body rolls or goes over a bump or pothole.
Numerical analysis of an automatic deployment to enhance the downforce of the vehicle
Published in International Journal of Ambient Energy, 2022
P. Gunasekar, S. Manigandan, K. Vijayaraja, A. Anderson, S. Venkatesh, Rakesh Vimal, R. Gokulnath
From the conceptual understanding of the above works, we designed a system which is operated to increase the downforce aerodynamics alone. Our concept was to increase the downforce without affecting the performance of the vehicle. The model is made of composite material for its unique feature and properties (Manigandan et al. 2019c; Manigandan et al. 2017b; Gunasekar et al. 2017). In recent days, composite fibres gained huge attention owing to its weight to strength ratio (Gunasekar and Manigandan 2017; Manigandan et al. 2019b). We use an automatically operated add-on device which is fixed at the bottom of the car. Whenever the driver decelerates the vehicle, the add-on device gets activated and it projects forward to increase the downforce of the vehicle. This leads to the enhancement of downforce of the vehicle. These add on devices are classified as primary add-on devices and secondary add-on devices. The primary add-on device is a main device to deviate the flow to increase the downforce of the vehicle. This is always in a fully deployed position. The secondary add-on device is made of two parts: one located at right side and the other at left side, based on the direction of the turn the secondary device is operated. If vehicle turns right, the left add-on device is deployed and vice versa. The major advantage of this design it can be used only on high ground clearance vehicle. Mostly all race cars are employed with less ground clearance to decrease the formation of drag; however, we can’t deploy sports car in off-road tracks and normal tracks with slopes. The ultimate aim of this design to increase the downforce and to make the ride in high speed even at the turning.
High downforce race car vertical dynamics: aerodynamic index
Published in Vehicle System Dynamics, 2018
Felipe Pereira Marchesin, Roberto Spinola Barbosa, Marco Gadola, Daniel Chindamo
Race cars must adjust the suspension system to maximise performance on track. This implies that the car ground clearance must be as low as possible. Due to aerodynamics, as speed increases, the suspension is subjected to higher loads and ground clearance decreases. At first glance, the key point is to set the race car to avoid touching the ground and because of that the suspension stiffness must be high. Nonlinear springs are not as common on race cars as on road cars, and normally a bump stop is used to help the spring to set the proper ground clearance against speed.
Developing an aluminum honeycomb barrier to represent a striking SUV in a side impact crash test
Published in Traffic Injury Prevention, 2021
Becky C. Mueller, Raul A. Arbelaez
Reevaluating current SUV geometries was a logical first step in redesigning the IIHS side impact barrier, as the vehicles upon which the original IIHS barrier were based are now over 20 years old (Arbelaez et al. 2002). Pickup shapes have remained largely similar over the past 20 years, but SUVs have become subtly more carlike, with sloping hoods and lower ground clearance, likely because of a combination of factors including fuel economy/aerodynamics, platform sharing with car models, and front-crash compatibility efforts. The largest difference for the updated barrier design was a lower overall height and ground clearance compared to the original barrier to better capture those SUV shape characteristics. A lower overall height was justifiable, since the upper sections of SUVs are typically comprised of relatively softer structures like headlights and grilles, which do not contribute significantly to loading in high-severity side crashes. Additionally, load cell wall data from the NHTSA full-width frontal tests show that despite having taller front-end structures, the overwhelming majority of loading for SUVs occurs at the height of the vehicle frame rails. These are characteristics shared by conventional engine vehicles and electric vehicles. Although electric vehicles were not included in this study, they are expected to increase representation in the future fleet. In the development of the original IIHS barrier, the higher front-end face (or hood) was intended to help drive the implementation of head-protecting side airbags; when vehicles were not equipped with them, the striking barrier face contacted the unrestrained dummy’s head. Current research indicates that this scenario is less applicable to tackling remaining injuries, since virtually all new vehicles are equipped with head-protecting side airbags, and current U.S. crashworthiness regulations will ensure their presence into the future. Additionally, real-world data indicate that the updated side impact test should focus on chest and pelvic injuries, not head injuries, to address the majority of remaining injuries.