Search Results

The 4M5 series of four-cylinder, in-line, direct-injection diesel engines has been released by Mitsubishi Motors Corporation for light and medium-duty trucks and buses. Featuring an updated structure and reflecting the employment of state-of-the-art technology in the design of every component, the new engine series offers high reliability and compact dimensions. Moreover, the new series well meets contemporary demands for high performance, low noise, and clean combustion.

It is well known that up-front FEA (finite element analysis) in product development will significantly reduce cycle time and improve product quality. The merit of using FEA in product design is evidenced by the mandate of its practice in the auto industry's QS9000 quality standard. Today, the usefulness of FEA in engineering product design is no longer an issue. Rather, the availability and cost for its extensive usage for product development is of concern. This is because until recently most FEA needed to be conducted by highly trained specialist. Recently, an alternative FEA implementation became feasible owing to the emergence of commercial software which takes advantage of several technological improvements such as P-element formulation and automatic mesh generation. As a result, some FEA jobs can now be conducted by less specialized engineers, offering the potential for fresh opportunities and challenges.

Getting the information on the inlet airflow and volume through the radiator was the important factor for the estimation of engine cooling performance. Now we developed an improved method of calculation by using STAR-CD, with improved fan modeling and a more precisely shaped vehicle model which includes the cab, front grill, radiator and engine, etc.. In this model, we can calculate more simultaneous airflow in the engine compartment and finally estimate more precisely the cooling performance by using a heat transfer calculation program, KULI. In this paper, we report on the newly developed CFD modeling method and calculated results.

The present state of knowledge on the handling behavior of articulated combination trucks is based on parametric studies made through truck model simulations. A detailed yaw-lurch planar mathematical model for articulated log-hauling combination doglogger trucks is developed in this study. Further, a thorough kinematic and dynamic analyses of log-hauling combination trucks, incorporating a sliding drawbar is carried out and the governing equations for the lateral and yaw planar motions are derived. Using a computer simulation model, the directional performance and the yaw and lateral stability of these articulated vehicles are fully investigated through a transient and harmonic response analyses. Finally, a parameter sensitivity analysis was carried out for different variables involved in the simulation model, to study the sensitivity of the steady-state response to various parameters.

This paper reports experimental results of engine starting trials conducted by the Army on common military vehicles using capacitor power sources. Improved starting performance can be obtained with the use of a capacitor, particularly at low temperatures. Power delivered by battery-capacitor systems are presented and compared to battery-only systems. Weight, volume, life, and cost comparisons for the two systems are given. A preliminary life-of-system cost analysis is presented and shows the potential for substantial cost savings to the Army from the use of capacitors in its vehicles.

In September of 1991, Allison Transmission Division launched the World Transmission product line with the release of the MD3060 automatic transmission into production. In January of 1996, Allison introduced the MD3066 transmission, the next response to market trends in automatic transmissions for use in trucks. The MD3066 transmission model has seen continuous improvement since 1996, including an increase in application ratings in January of 1998, anticipating the needs of the target marketplace. This paper discusses the features, design and development of the MD3066 transmission.

A case study of failure analysis of a cast iron center plate of a clutch and brake combination, used in presses to stamp automotive components, using finite element analysis has been presented. To predict mechanical failures, it is quite common to use maximum principle stresses for brittle materials like cast iron. However, in this analysis, the stress plots could not account for the cracks in the failed samples. A metallurgical test showed that the samples had been subjected to high thermal loads on the clutch face. A thermal analysis, after assuming that the center plate was behaving as a mild ductile material, correlated analysis with actual failure.

Heavy lorries and trailer combinations cause many serious traffic accidents. There in Finland alone have been approximately100 killed per year by heavy duty vehicles in 1990's. Improvements in inspection methods of brake systems increase traffic safety. In Finland dynamometer measurements have been used since 1960´s, and its advantages are stable measuring conditions, high repetability and short inspection time. The Finnish Traffic Office and the Finnish Motor Vehicle Registration Centre have been interested in correlations of road retardation and dynamometer measurements and therefore established Dynamet-brake research project in 1993. This paper contains a research which aims to find out correlations of retardation prediction for lorries and trailer combinations by comparing road braking tests and dynamometer measurements, and secondly to improve the dynamometer measurement system at inspection stations.

Air conditioning is defined as the process of treating air so as to control simultaneously its temperature, humidity, cleanliness and distribution to meet the requirements of the conditioned space. As in the definition, the important actions involved in the operation of an air conditioning system are temperature and humidity control, air purification and movement. For these conditions this paper proposes a Automatic Climate Control(ACC) system of the bus. The system has cooling, heating, and dehumidifying modes, and is governed by dual 8-bit microprocessors. These modes are broken down into sub-modules dealing with control of the compressor, blower speed, damper position, air purifier, ventilators, preheater, air mixing damper and so on.

A demonstrator for a vision enhancement system to be used at night has been developed and tested. The intention of the system is not to drive a vehicle using a small video image but to inform the driver early and far reaching about the course of the road and about obstacles, pedestrians and bikers. For the first time laser diodes emitting in the near infrared are applied as light sources in additional headlights. As a camera a low noise CCD video camera is used. The information in the video image is better than the information, which the driver can see with his eyes. To present the video image to the driver, a LCD display with an optic to generate a virtual image in a distance of some meters is used. The demonstrator was tested by 20 truck drivers resulting in a good acceptance of the system. Prototype development to implement an improved system into a bus is under way.

Multiplexing provides a way to reduce wiring bundle size, weight and cost. It supports controls and communications that cannot be handled easily by discrete wire. Both SAE J1708 and SAE J1939 are being used as part of the vehicle's electrical and electronic systems. Advancements in semiconductors, software, electronics, connectors and cabling have led to improved multiplexing systems. Issues in cost, size, validation and testing have been studied. A common goal for many in this field is to make continuous improvements for the whole electrical system in the vehicle. This paper presents practical perspectives on physical layer implementations.

The Northeast suffers from levels of ozone and fine paniculate mater which threaten public health. While diesel powered buses can reduce reliance on personal automobiles, they are a significant source of the emissions which make up these air pollution problems. Electric powered transportation can make a contribution to meeting society's desires for clean air and transportation services. However, for this technology to be acceptable to transit operators and the public, it must demonstrate that it is not only clean, but can provide a level of service competitive with conventional technology, while satisfying riders' needs and comfort. To this end, the Northeast Advanced Vehicle Consortium (NAVC) working with transit operators in the northeast, Advanced Vehicle Systems, Inc (AVS), Solectria Corp., and EVermont has undertaken a project to redesign a 22-foot electric shuttle bus. In total, five buses will be built and operated at three Northeast locations.

This technical paper discusses various recent developments in Alternators and Starters used in Heavy-Duty applications such as Class 5,6,7& 8 Trucks, Buses and Emergency Vehicles. The subject matters included are recent technological advancements, changes in application environments, and practical solutions to increase the time to first failure. This paper also provides some useful tips for the designers of Trucks, Buses and Emergency Vehicles about integration of Alternators and Starters into their vehicle design.

Fire apparatus are a particularly sensitive vehicle application when considering the management of the electrical power and power distribution system. Modern apparatus are equipped with a multitude of control systems critical to the mission of the apparatus, including engine controls, transmission, water pump, aerial hydraulics, lighting, warning, communications and instrumentation systems. The dependency of fire apparatus on these control systems, coupled with the large electrical loading of the emergency warning and lighting systems, require that a sound power distribution and energy management system be engineered into the vehicle electrical system.

The paper reviews the Cranfield Impact Centre (CIC) experience with dynamic simulation of the collapse behaviour of minibus and coach body structures in rollovers and frontal impacts and the interaction between occupants and seats in a variety of loading scenarios. This work supported development of the: a. ECE (UN-Geneva) and EEC (European Union) safety standards for rollover strength and safety of seats with belts; b. Rollover safety Type Approval method, combining numerical simulation and component tests; c. Safety structures for rollover protection and in passenger seats. Characteristic extracts from various projects demonstrate not only the usefulness and capability of dynamic simulation, but also the difficulties associated with this rapidly developing field of safety technology.

Current vehicle electronic control units (ECUs) communicate with each other through networks. Easy integration of these ECUs into a system obviously requires well-standardized network interfaces and corresponding components, which meet the standard properly. One efficient means to ensure that communication interfaces are compliant with the standard is a conformance test standard. As CAN is a widely used communication standard interface in vehicles ISO has worked out a CAN conformance test standard, which is expected to be published as a Draft International Standard - DIS - by end of 1998. This article describes the developing standard, the implementation of a corresponding tester, and how conformance tests are performed. Further, more necessary extensions for more efficient conformance testing with better test coverage are discussed.

Today's car manufacturers are integrating evermore complex multi-media equipment into their vehicles in order to meet the changes in consumers buying behavior. Examples of such equipment range from the car radio/cassette player, through audio CD Changer and mobile telephones through to sophisticated car navigation and video systems. In order to efficiently integrate all of these devices together and allow products from different manufacturers to inter-operate, a cost-effective evolutionary multimedia networking technology is required.

Consumer electronic products developed for business, convenience and communication purposes, in vehicle applications, provide advanced features at a competitive price. However, the industry is challenged with providing a plug and play interfacing method for interconnecting these electronic products with each other and with the wealth of information that is available on the vehicle multiplexed serial data links. This paper will examine current industry trends in linking consumer products in passenger vehicles and suggests an approach for using this technology in commercial vehicles. Highlights of the Universal Serial Bus, the Microsoft/ Clarion Auto PC and the Intelligent Transportation System Data Bus will be presented. Various scenarios are offered to promote the benefits of bringing the information age into the commercial vehicle market.

The free-rolling cornering, straight-line braking, and pull force properties of a small sample of tire specifications is examined. This is done to examine potential differences between the specifications and the statistics of force and moment measurements. Two steer axle specifications, two drive axle specifications, and a trailer specification are considered, In addition, the evolution of properties for one drive axle specification is followed from new to naturally worn-out to retreaded. The summarized data is available from SAE Cooperative Research on electronic media.

The ability to accurately simulate vehicle dynamics behavior with a mathematical model is limited by the quality of the tire model. In fact, the tire is often the single most important component in determining correlation between a mathematical vehicle model and measured experimental results. Tire data for heavy trucks are more difficult and expensive to acquire than passenger car and light truck data, and, consequently, there has been little published experience testing or modeling these tires. This paper shows how the analysts can integrate heterogenous tire modeling methods into one coherent tire model suitable for the simulation of an over-the-road 18-wheel tractor-trailer configuration. The methods used in this paper are: Tire F&M modeling that represents the effect of tread wear, water depth, and speed, as well as combined longitudinal and lateral slip conditions.