This class will provide the student with the skills, knowledge, and abilities to interpret, analyze and apply Heavy Vehicle Event Data Recorder (HVEDR) data in real world applications. This course has been designed to build on the concepts presented in the SAE course Accessing and Interpreting Heavy Vehicle Event Data Recorders (ID# C1022).
Baja SAE is an intercollegiate competition where teams design and build a single-seat off-road vehicle that is powered by a small 10 HP Briggs & Stratton engine. Due to this power constraint, it is crucial to optimize the vehicle's weight and performance. The purpose of this paper is to demonstrate the process of simulating, designing, manufacturing, and testing the gearbox of the vehicle. The design process began by creating a vehicle dynamics simulation, which included engine performance, CVT Shifting, tire slipping, vehicle mass, rotational inertia, air drag, rolling resistance, weight shift, and drivetrain efficiency. These calculations predicted acceleration times, top speed, and optimal gear ratio. An often-neglected parameter that was analyzed was the rotational inertia in the drivetrain system. The results showed the effective mass of the vehicle increased 12% above the weight of the vehicle, primarily due to the weight and size of the CVT primary pulley.
Knowledge of the forces on the vehicle is necessary for designing most of the vehicle subsystems, however little knowledge of the dynamic forces on small off-road vehicles is available. To measure the vertical and longitudinal forces on the tires of an off-road vehicle, a custom strain gauge system was designed and combined with Quarq tire pressure sensors while running in off-road conditions. The strain gauge system consisted of a carefully calibrated half-bridge Wheatstone bridge of 350 Ohm resistors in bending, feeding the change in voltages into the 20-bit ADC of a Cypress Semiconductor PSoC 5LP microcontroller for data interpretation and then recorded onto an SD card for later analysis. The Quarq Tyrewiz tire pressure sensors were placed on both the front and rear tires and the recorded pressures were converted to forces on the tire through calibration and helped remove the uncertainty of certain strain gauge values. Experimental data was found to agree with suspension models.
On account of the traditional friction brake for heavy-duty truck, the massive quantity of heat accumulating constantly because of frequent using of friction brake system in the long and steep downhill road leads to brake temperature rising rapidly. Affected by structure frictional couple installed in the closed environment of the brake drum, it is difficult to dissipate the heat in time via heat conduction, heat radiation and heat convection, and the heat fade phenomenon of the brake emerges easily. The heavy-duty truck would be in danger because of braking efficiency descending. This paper proposes an active water-cooled drum brake system to solve the problem. According to the principle of engineering thermodynamics, the structure and size of the back-stretching water jacket of brake shoe and the inner riveted the friction plate of brake drum are designed with restrained of GB 12672-2014 "Technical requirements and testing methods for commercial vehicle and trailer braking systems".
This report summarizes initial results and findings of a model developed to determine the braking performance of commercial motor vehicles in motion regardless of brake type or gross weight. Real-world data collected by Oak Ridge National Laboratory for a U.S. Department of Energy study was used to validate the model. Expanding on previous proof-of-concept research showing the linear relationship of brake application pressure and deceleration additional parameters such as elevation were added to the model. Outputs from the model consist of coefficients calculated for every constant pressure braking event from a vehicle that can be used to calculate a deceleration and thus compute a stopping distance for a given scenario. Using brake application pressure profiles derived from the dataset, stopping distances for light and heavy loads of the same vehicle were compared for various speed and road grades.
One of the major discomforts while driving any medium to heavy commercial vehicle is brake judder. Brake juddering can be defined as vibrations felt on steering wheel or brake pedal or cabin floor, when brakes are applied at certain speeds and pressures. The frequencies of this judder lie as high as 500 Hz to as low as 10Hz. The brake juddering can be caused by a number of factors because of which providing universal solution only from brakes point of view is difficult. Some of the causes are related to part fitment, part quality, material selection, manufacturing process, Design consideration, environmental factors, peripheral aggregates etc. This paper gives us a brief idea about resolution of juddering problem in intermediate commercial vehicle by DOE method, and this methodology can be applied in heavy commercial vehicles also.
The braking systems for modern day commercial vehicles with GVWs ranging above 7.5 metric tons use the typical s-cam drum brake system, where pressurised air is the actuating medium. The s-cam drum brake systems are popular today even after the advent and penetration of air disc brake systems, the main reasons being, cost-effectiveness, robustness, satisfactory performance and good component life. However, the brake systems of commercial vehicles (both M and N category) are frequently grappled with NVH issues particularly in the form of brake squeal noise (low frequency and high frequency). The noise with frequency more than 500 Hz can be generally defined as brake squeal. There has been a lot of work done and is being continued, at theoretical level, analytical level and experimental level to tackle with this issue.
S-cam air brake system is provided in almost all commercial vehicles having tonnage above 7.5-ton. In S-Cam brake system, drum to liner gap (henceforth referred to as 'liner gap' or simply 'gap' for convenience) range is an important factor which can impact braking behavior during brake application. Different OEMs (Original Equipment Manufacturers) define different liner gap ranges between S-cam brake lining and brake drum. This range depends majorly on the internal mechanism deployed in ASA (Auto Slack Adjuster). When these liner gaps start lowering i.e. when they fall in the range of 0 to 0.4 mm, or they become unstable (checked by feeler gauge at inspection window provided on dust cover of S-cam) then it starts impacting brake behavior in the subject vehicles.
This SAE EDGE Research Report identifies key unsettled definitions of the role of smart assembly tools in the Industry 4.0 world. “Smart” refers to tools that are “specific, measurable, achievable, reasonable/realistic, and time bound.” Smart assembly tools are used in all industries, including automotive, aerospace, and space. These tools are employed for measuring, inspecting, gauging, drilling, and installing all existing fastening systems. The role of an assembly tool inside the Industry 4.0 environment is quite important as the smart, intelligent assembly tools have an enablement function. Smart assembly tools have a huge influence on Information and Communication Technology (ICT), assembly cost reduction, process control, and even the product and process quality. These four four domains—and their undefined nature—are the focus of this SAE EDGE Research Report.
Increased efficiency and emission reduction have, in recent years, introduced several changes in the architecture of agricultural tractors transmissions. As one of the leading rolling bearing manufacturers for this industry, Schaeffler has explored energy saving potentials related to rolling bearings friction reduction. Starting point of the activity is the actual status of the design of tractor transmission manufactured by one of the key players in the sector.
The recent commercial vehicle research emphasis to control noise, vibration, and harshness (NVH). The present study analyzes the performance of a hybrid suspension system for light commercial passenger vehicles under different road conditions. The full car model mathematical model and the experimental investigations were carried out under periodic and discrete road inputs. The parameters like the driver seat acceleration, body acceleration, suspension travel, tire displacement, pitching, and rolling motions were observed. The influence of hybrid suspension system related to driver seat acceleration as compared with the passive model, also simulation model and experimental model. Finally the proposed system improves the comfort level in terms of driver acceleration and keeping the handling performance within the acceptable range with small degradation.
In this work, Improved design and structural calculations of connecting rod of IC engine has been performed. From the functionality point of view, connecting rod must have the higher inertia at the lowest weight. The forces acting on connecting rod are: - Peak combustion pressure force, inertia force of reciprocating masses, Weight of Reciprocating parts and frictional forces due to cylinder wall thrust. It experiences complex loading of compression and tensile under cyclic process. Design calculations are analysed for the axial compressive/ tensile loads and considering the fatigue life of connecting rod. Calculations are based on Actual Endurance limit of connecting rod. To find out Actual Endurance limit, its working temperature factor, surface finish factor, Size factor, stress concentration & reliability factor are derived and considered for calculations. To develop failure criteria, stress patterns of fluctuating loads are properly identified.