Search Results

“Today, wearing parts are regularly subjected to abnormal loading conditions. They must be able to accept these conditions without failure. In continuous operations, unscheduled downtime greatly increases maintenance costs, not to mention the cost of lost production. White iron castings offer premium abrasion resistance for many of these applications, but are often not used due to the possibility of brittle failure and the difficulty of mechanical attachment. This paper discusses the properties and applications of a composite of martensitic white iron and mild steel. This laminate will accept medium to high impact without loss of service failure, and can be installed by mechanical means or with welded attachment.”

The objective of this paper is to delineate the importance of pictures, i.e., graphical models, in documenting and communicating the high level functionality of a complex system, primarily for embedded software requirements and specifications. An overview is given of various graphical techniques and methodologies for modeling complex systems. The aspects (advantages and disadvantages) relating to different categories of modeling are outlined. Discussion of complex systems extends beyond the functional/software aspects of product design to both process and project modeling. The author shares personal observations and experiences with modeling, and tools used.

Effective requirements elicitation and management is a common need in supplier-OEM relationships, and continues to play a vital role in all aspects of the product development lifecycle. While traditional methods address the business goals for requirements and provide guidance in ensuring the accuracy of the “Descriptive-Prescriptive-Explanatory” outputs for requirements gathering and documentation, engineering organizations continue to encounter challenges with respect to capturing and communicating change, accommodating the addition of relevant design details and efficient propagation to inform development. These challenges become more difficult to overcome in mechatronic systems, which combine mechanical systems with integrated software. As software development can produce an overwhelming volume of information that requires accurate tracking and proliferation, it cannot be effectively managed using traditional hardware-centric systems.

Maintaining the fuel temperature and fuel system components below certain values is an important design objective. Predicting these temperatures is therefore one of the key parts of the vehicle’s thermal management process. One of the physical processes affecting fuel tank temperature is fuel vaporization, which is controlled by the vapor pressure in the tank, fuel composition and fuel temperature. Models are developed to enable the computation of the fuel temperature, fuel vaporization rate in the tank, fuel temperatures along the fuel supply lines, and follow its path to the charcoal canister and into the engine intake. For diesel fuel systems where a fuel return line is used to return excess fluid back to the fuel tank, an energy balance will be considered to calculate the heat added from the high-pressure pump and vehicle under-hood and underbody.

A new Artificial Intelligence (AI) “Expert System” software technology has been developed which shows real promise as the core platform of the Decision Support System for Truck Repair. The “Expert system” consists of a Model Based reasoning mechanism, and a Rule Based shell along with an on-line documentation and graphics capability. This technology combines the development speed and accuracy of Model Based technology, the precision of Rule Based expert systems along with the ease-of-use associated with a “Hypertext” information system.

Low crew productivity and extension of service intervals past design limits are the two major reasons so many heavy equipment PM programs are ineffectual. ALPM, or Assembly Line Preventive Maintenance is an innovative system for equipment servicing, providing management scheduling tools and the necessary controls. The system has a successful track record in a number of severe applications.

This SAE Standard includes complete general and dimensional specifications for those types of pipe, filler, and drain plugs (shown in Figures 1 to 6 and Tables 1 to 4) commonly used in automotive and related industrial applications.

This standard includes complete general and dimensional specifications for those types of pipe, filler, and drain plugs (shown in Figs. 1-6 and Tables 2-4) commonly used in automotive and related industrial applications.

This SAE Standard includes complete general and dimensional specifications for those types of pipe, filler, and drain plugs (shown in Figures 1 to 6 and Tables 1 to 4) commonly used in automotive and related industrial applications.

Determining pre-impact acceleration and braking performance values is an important aspect of reconstructing collisions. Collision analysts may have to rely upon performance testing of an exemplar vehicle for reliable data to use in traffic collision reconstruction cases. These performance characteristics are well documented for many vehicle classes, but are limited when discussing urban transit style buses. The constant stop and go urban driving conditions in which they operate constantly challenge the vehicle components. Because of the heavy weights and operating conditions, auxiliary braking systems are often installed to prolong the life of the service brakes. A series of idle acceleration, maximum acceleration, and maximum braking tests were conducted using urban transit style buses that are currently in-service in a large metropolitan area. The initial braking target speed for these braking tests was 64 kph (40 mph).

Apple’s mobile phone LiDAR capabilities were previously evaluated to obtain geometry from multiple exemplar vehicles, but results were inconsistent and less accurate than traditional ground-based LiDAR (SAE Technical Paper 2022-01-0832. Miller, Hashemian, Gillihan, Helms). This paper builds upon existing research by utilizing the newest version of the mobile LiDAR hardware and software previously studied, as well as evaluating additional objects of varying sizes and a newly released software not yet studied. To better explore the accuracy achievable with Apple mobile phone LiDAR, multiple objects with varied surface textures, colors, and sizes were scanned. These objects included exemplar passenger vehicles (including a motorcycle), a fuel tank, and a spare tire mounted on a chrome wheel. To test the repeatability of the presented methodologies, four participants scanned each object multiple times and created three individual data sets per software.

The incidence of fire in heavy trucks has been shown to be about ten times higher under crash conditions than occurs in passenger vehicles. Fuel tank protection testing defined in SAE standard J703 was originally issued in 1954 and presently echoes federal regulations codified in 49 CFR 393. These tests do not reflect dynamic impact conditions representative of those that can be expected by heavy trucks on the road today. Advanced virtual testing of current and alternative fuel tank designs and locations under example impact conditions is reported. Virtual testing methods can model vehicle to vehicle and vehicle to fixed object impacts. These results can then be utilized to evaluate and refine fuel tank protection system design approaches.

This SAE Recommended Practice establishes minimum performance requirements for new pneumatic valves when tested in accordance with the test procedure outlined in SAE J1409. The performance requirements will include: a Input-output performance b Leakage characteristics c Low temperature performance d Elevated temperature performance e Corrosion resistance performance f Endurance testing g Structural integrity

This SAE Recommended Practice establishes minimum performance requirements for new pneumatic valves when tested in accordance with the test procedure outlined in SAE J1409. The performance requirements will include: a Input-output performance b Leakage characteristics c Low temperature performance d Elevated temperature performance e Corrosion resistance performance f Endurance testing g Structural integrity

This SAE Recommended Practice establishes minimum tolerance requirements for pilot operated and mechanically actuated modulating type valves, and through type valves used in the service brake control system when tested in accordance with the test procedure outlined in SAE J1859. This document applies to the nominal input-output characteristics as specified by vehicle original equipment manufacturer and labeled by the valve manufacturer as outlined in SAE J1860. The tolerance requirements will include: a Crack (opening) pressure or force. Crack pressure may be measured at the initial output pressure or as the pressure differential before output pressure exceeds 14 kPa (2 psi). Crack force may be measured at initial output pressure or before output pressure exceeds 14 kPa (2 psi). b Pressure differential (input-output)

This SAE Recommended Practice establishes minimum tolerance requirements for pilot operated and mechanically actuated modulating type valves, and through type valves used in the service brake control system when tested in accordance with the test procedure outlined in SAE J1859. This document applies to the nominal input-output characteristics as specified by vehicle original equipment manufacturer and labeled by the valve manufacturer as outlined in SAE J1860. The tolerance requirements will include: a Crack (opening) pressure or force. Crack pressure may be measured at the initial output pressure or as the pressure differential before output pressure exceeds 14 kPa (2 psi). Crack force may be measured at initial output pressure or before output pressure exceeds 14 kPa (2 psi). b Pressure differential (input-output)

This SAE Recommended Practice establishes performance guidelines of the air reservoir systems used on trucks, towing trucks, truck-tractors, trailers, and converter dollies with GVWRs over 10 000 lb designed to be used on the highway. NOTE: Compliance with this document does not guarantee compliance with the air reservoir requirements of FMVSS 121.

This book provides property and performance data for all types of aluminum alloy castings and reviews and describes the factors that contribute to and affect those properties, including composition, microstructure, casting process, heat treatment, and quality assurance. The electronic publication features extensive collections of property and performance data, including previously unpublished aging response curves, growth curves, and fatigue curves, presented in consistent formats to enable easy comparisons among different alloys and tempers. The authors have endeavored to address all of the casting process technologies available for aluminum alloys. Engineering information is included for expendable mold, permanent mold, and pressure die casting processes and their variations. The focus of the process coverage is to review the effects of process selection and process variables on casting properties and performance.

To compete with the current market trends there is always a need to arrive at a cost effective and light weight designs. For Commercial Vehicles, an attempt is made to replace existing Gear Shift Fork from FC Iron (Ferro Cast Iron) to ADC (Aluminum Die Casting) without compromising its strength & stiffness, considering/bearing all the worst road load cases and severe environmental conditions. ADC has good mechanical and thermal properties compared to FC Iron. Feasible design has been Optimized within the given design space with an extra supporting pad for load distribution. Optimization, Stiffness, Contact pattern has been done using OptiStruct, Nastran & Ansys for CAE evaluation. A 6-speed manual transmission is used as an example to illustrate the simulation and validation of the optimized design. Advanced linear topology optimization methods have been addressed as the most promising techniques for light weighting and performance design of Powertrain structures.

The turbulent wake behind a truck is responsible for a considerable proportion of the total aerodynamic drag. There is evidence to suggest that the underbody flow affects the wake topology, although this interaction is not well understood. Typical truck trailer underbodies are geometrically very complex and have a range of bluff bodies - such as the wheel and axle assembly, structural beams or the secondary fuel tank for refrigerated trucks - attached. These components block the underbody flow and erode its momentum. However, most of the previous studies of the wake flow have used models with clean underbodies. It is thus uncertain whether the wake shapes found by these studies accurately represent the wake topology behind a real truck with a detailed underbody.