Search Results

A program was developed that provides a user friendly interface for developing and testing shift tables in a powershift transmission. This program is Windows based and runs on an IBM compatible P.C. When coupled with a suitable controller, transmission designers have a useful tool for the development of transmission shift timing. The system is designed to be used in an engine test cell or for actual vehicle tests. This allows the vehicle operator to call up and edit shifts on a P.C. screen and then drive the vehicle using the new shifts. This allows the operator to evaluate results of real time shifts immediately.

ZF uses innovative motor cooling, winding technology and its transmission heritage to produce a more efficient and powerful drivetrain for electric vehicles.

A new line of on-highway transmissions has been designed and developed by Allison Transmission Division. This new product line, identified as the World Transmission Series (WT), has been designed with emphasis on cost-effectiveness, greater integration with vehicle systems and advanced technology to meet market demands into the 21st century. New design concepts both in power train component arrangement and electronic controls have been coupled utilizing concurrent engineering and systems engineering principles. The result is a customer-driven product line which, when produced by Allison, will exceed world class standards of quality, performance and value.

This SAE Recommended Practice establishes uniform test procedures and performance requirements for the defrosting system of enclosed cab trucks, buses, and multipurpose vehicles. It is limited to a test that can be conducted on uniform test equipment in commercially available laboratory facilities. Current engineering practice prescribes that for laboratory evaluation of defroster systems, an ice coating of known thickness be applied to the windshield and left- and right-hand side windows to provide more uniform and repeatable test results, even though under actual conditions such a coating would necessarily be scraped off before driving. The test condition, therefore, represents a more severe condition than the actual condition, where the defroster system must merely be capable of maintaining a cleared viewing area.

Cast iron is generally thought of as a weak, dirty, cheap, brittle material that does not have a place in applications requiring high strength and defined engineering properties. While gray cast iron is relatively brittle by comparison with steel, ductile iron is not. In fact, ductile iron has strengths and toughness very similar to steel and the machinability advantages make an attractive opportunity for significant cost reductions. Gray and ductile iron bar stock is commercially available and can be used as a direct replacement in applications that are currently being made from carbon steel bar. Ductile iron bar stock conversions are very prevalent in many fluid power applications including glands and rod guides, cylinders, hydrostatic transmission barrels and in high-pressure manifolds. Automotive gears are being converted to ductile iron for its damping capacity and cost reductions.

Bus drivers are daily exposed to whole-body vibrations (WBV) submitted to risks for develop health problems related to these conditions. Numerous studies focused to quantify and identify the risks that drivers are exposed have been developed in recent years. Many factors influence the transmission of vibration to the body. Road type may be an important factor in determining the WBV exposure a bus driver receives. In urban areas, common types of routes include several road surfaces like: smooth highway, older rough freeway, pavement, bumpy, speed humps, and others. The purpose of this study was to determine whether different kinds of road surfaces, found in urban routes, cause different WBV responses, and determine the influence for each road type in daily exposure to WBV according the standard ISO 2631-1 (1997).

The wheel motor is a combination of hydro-motor and planetary transmission. Industrial, agricultural, construction and various types of public utility vehicles, which due to their design cannot use axle drives, make increasing use of the individual wheel drive. Speed, torque transmission, wheel bearings, valves for hydraulic operation and hydraulic engagement/disengagement are some of the requirements for wheel motor drives.

Formulas are derived to show that moving elements of a drive train can contribute to the energy seen by the clutch plates. Oscillograph traces, sample calculations and photographs of failed plates show actual energy at failure of test plates. The formula is presented for calculating instantaneous energy when coefficient of friction, apply pressure and slip speed are known or can be estimated.

Shift quality of a manual transmission is a critical characteristic that is requires utmost care by the designers while structuring the transmission. Shift quality is affected by many factors viz. synchronizer design, shift fork design, shifter design, gear design, transmission oil selection etc. Designers have realized that shift fork is critical element for improving shift feel of a transmission. This paper focuses upon the reduction in weight of the overall transmission shift system by using steel inserts in aluminum shifter forks. No compromise on the stiffness and strength of the shift fork of a manual transmission is done. Stiffness and strength of shifter fork is optimized using contact pattern analysis and stiffness analysis on MSC Nastran. All the subsystem (i.e. synchronizer and the shift system component) are constrained to optimize the shift fork stiffness. A 5-speed manual transmission is used as an example to illustrate the same.

This SAE Standard specifies minimum performance and test criteria for brake systems to enable uniform assessment of the braking capability of walk-along self-propelled work machines with a mass greater than 115 kg. Service and parking brake systems are covered by this document.

This SAE Standard specifies minimum performance and test criteria for brake systems to enable uniform assessment of the braking capability of walk-along self-propelled work machines with a mass greater than 115 kg. Service and parking brake systems are covered by this document.

The test code establishes wheel slip brake control system capabilities with regard to:

Light and Medium Duty Trucks (N.A. Classes 2–7) make up of a wide variety of vehicle configurations. These vehicles, in addition to providing the basic hauling needs of the industry, also provide distinct operational features dictated by the vocation they serve. This results in additional auxiliary equipment and control features being employed. The control system for Allison Transmission's new 1000/2000/2400 Series™ transmission was designed to satisfy the many requirements of this complex market. This paper will describe these features and how they interact with various control aspects of the vehicle. Also, future control features will be discussed.

After many years of successful Visco fan drive applications, Behr has now transferred the Visco technology to the coolant pump drive. The continuously variable Visco drive allows the coolant pump to deliver the optimum flow dependent upon the requirements, therefore reducing the drive power to the minimum possible. Up to now coolant pumps, world wide, have almost always been powered by direct, uncontrolled drives. Consequently, the delivery and the power consumption have been directly related to the engine speed, which, in many conditions, results in an unnecessarily high flow rate. The potential to reduce the flow rate is inherent within the Visco coolant pump. As a concept with continuous control of the impeller speed it has been found to be more fuel efficient than incremental impeller speed control or concepts which only restrict or divert the flow rate. The torque transmission via the shear forces of a silicone oil results in a robust and wear-free drive unit.

The dynamics of hypoid or spiral bevel gears like most high-speed precision gears employed in the powertrains of automobiles, commercial trucks, and off highway vehicles are significantly influenced by the design of the shafts. The finite element modeling approach is one of the useful methodologies applied to perform gear dynamic analysis. One of the major advantages of the finite element modeling approach is that it can account for the gear-shaft-bearing assembly design more accurately than other modeling approaches, for example, the lumped parameter modeling approach. In this paper, the finite element formulation, which can generally represent more complete characteristics of the gear-shaft-bearing assembly design, is employed to investigate how the temperature change, shaft material type and shaft size influence the dynamics of spiral bevel gear system.

This paper proposes a technology to reduce vehicle surge during towing that utilizes motors and shifting to help ensure comfort in a parallel HEV pickup truck. Hybridization is one way to reduce fuel consumption and help realize carbon neutrality. Parallel HEVs have advantages in the towing, hauling, and high-load operations often carried out by pickup trucks, compared to other HEV systems. Since the engine, motor, torque converter, and transmission are connected in series in a parallel HEV, vehicle surge may occur when the lockup clutch is engaged to enhance fuel efficiency, similar to conventional powertrains. Vehicle surge is a low-frequency vibration phenomenon. In general, the source is torque fluctuation caused by the engine and tires, with amplification provided by first-order torsional driveline resonance, power plant resonance, suspension resonance, and cabin resonance. This vibration is amplified more during towing.

Vehicle drawbar testing was conducted in order to establish the relative performance of all wheel drive electric and viscous clutch transfer case systems. The drawbar tests of a Ford Aerostar system with an electric clutch transfer case are compared to viscous clutch systems in a GM Astro and a Chrysler Grand Cherokee. The empirical test results and theoretical comparison show that the electric clutch transfer case system has a greater amount of torque transfer and its reaction time is faster.

The need for expert systems in the Heavy Truck and Bus Industry is rapidly approaching a critical point in time. This time reference is the revised emission standards and requirements for heavy duty diesels. This need is related to the influx of electronically controlled engines and their companion the electronically controlled transmission as well as the present shortage of skilled mechanics. This paper discusses the conceptual approach and reasons that expert systems are well suited as a diagnostic aid for vehicular repair. This paper also discusses the implementation of a commercially available expert system for the diagnosis of class 7 and 8 vehicles. The body of this paper will be divided into four discussions. First, applicability of AI/KB programs used for vehicle diagnostics. Second, the use of expert systems to diagnose electronically controlled power modules and their related interactivities with the vehicle.

The transition towards electrification in commercial vehicles has received more attention in recent years. This paper details the conversion of a production Medium-Duty class-5 commercial truck, originally equipped with a gasoline engine and 10-speed automatic transmission, into a battery electric vehicle (BEV). The conversion process involved the removal of the internal combustion engine, transmission, and differential unit, followed by the integration of an ePropulsion system, including a newly developed dual-motor beam axle that propels the rear wheels. Other systems added include an 800V/99 kWh battery pack, advanced silicon carbide (SiC) inverters, an upgraded thermal management system, and a DC fast charging system. A key part of the work was the development of the propulsion system controls, which prioritized drivability, NVH suppression, and energy optimization.