Refine Your Search

Topic

Author

Affiliation

Search Results

Technical Paper

Performance and Emissions of an LPG Lean-Burn Engine for Heavy Duty Vehicles

1999-05-03
1999-01-1513
Performance and emissions of an LPG lean burn engine for heavy duty vehicles were measured. The piston cavity, swirl ratio, propane - butane fuel ratio, and EGR were varied to investigate their effects on combustion, and thus engine performance. Three piston cavities were tested: a circular flat-bottomed cavity with sloped walls (called the “bathtub” cavity), a round bottomed cavity (called the “dog dish” cavity), and a special high-turbulence cavity (called the “nebula” cavity). Compared to the bathtub and dog dish cavities, the nebula type cavity showed the best performance in terms of cyclic variation and combustion duration. It was capable of maintaining leaner combustion, thus resulting in the lowest NOx emissions. High swirl improved combustion by achieving a high thermal efficiency and low NOx emissions. In general, as the propane composition increased, cyclic variation fell, NOx emissions increased, and thermal efficiency was improved.
Technical Paper

Emissions from Buses with DDC 6V92 Engines Using Synthetic Diesel Fuel

1999-05-03
1999-01-1512
Synthetic diesel fuel can be made from a variety of feedstocks, including coal, natural gas and biomass. Synthetic diesel fuels can have very low sulfur and aromatic content, and excellent autoignition characteristics. Moreover, synthetic diesel fuels may also be economically competitive with California diesel fuel if produced in large volumes. Previous engine laboratory and field tests using a heavy-duty chassis dynamometer indicate that synthetic diesel fuel made using the Fischer-Tropsch (F-T) catalytic conversion process is a promising alternative fuel because it can be used in unmodified diesel engines, and can reduce exhaust emissions substantially. The objective of this study was a preliminary assessment of the emissions from older model transit operated on Mossgas synthetic diesel fuel. The study compared emissions from transit buses operating on Federal no. 2 Diesel fuel, Mossgas synthetic diesel (MGSD), and a 50/50 blend of the two fuels.
Technical Paper

Influence of Fuel Aromatics Type on the Particulate Matter and NOx Emissions of a Heavy-Duty Diesel Engine

2000-06-19
2000-01-1856
The influence of fuel aromatics type on the particulate matter (PM) and NOx exhaust emissions of a heavy-duty, single-cylinder, DI diesel engine was investigated. Eight fuels were blended from conventional and oil sands crude oil sources to form five fuel pairs with similar densities but with different poly-aromatic (1.6 to 14.6%) or total aromatic (14.3 to 39.0%) levels. The engine was tuned to meet the U.S. EPA 1994 emission standards. An eight-mode, steady-state simulation of the U.S. EPA heavy-duty transient test procedure was followed. The experimental results show that there were no statistically significant differences in the PM and NOx emissions of the five fuel pairs after removing the fuel sulphur content effect on PM emissions. However, there was a definite trend towards higher NOx emissions as the fuel density, poly-aromatic and total aromatic levels of the test fuels increased.
Technical Paper

AQUAZOLE™: An Original Emulsified Water-Diesel Fuel for Heavy-Duty Applications

2000-06-19
2000-01-1861
1 Since 1997 the ELF group has been working on a new fuel designed in priority for use with urban services (buses, lorries). Basically, it is a diesel/water emulsion stabilised by a series of new additives. A lot of testing programmes on engine and vehicles test benches was carried out. They have clearly shown that with this new fuel there is a reduction of nitrogen oxide emissions by up to 30% and black smoke by up to 80%, without any technological modifications being necessary as against EN 590 diesel fuel marketed normally. The water content is, however, the cause of a certain loss in engine performances. Nevertheless, hydrocarbon consumption is reduced by up to 4%. The use of an oxidation catalyst is compatible with a water-diesel emulsified fuel and results in larger emission benefits. Furthermore, a 50 ppm sulphur emulsion with a continuously regenerating particle filter give a particle reduction of 90%.
Technical Paper

New Quiescent Combustion System for Heavy–Duty Diesel Engines to Overcome Exhaust Emissions and Fuel Consumption Trade–Off

2000-06-19
2000-01-1811
In the next few years, the USA, EU, and Japan plan to introduce very stringent exhaust emissions regulations for heavy–duty diesel engines, in order to enhance the protection air quality. This builds upon the heavy–duty diesel engine exhaust emissions regulations already in effect. At the same time, improvement in fuel consumption of heavy–duty diesel engines will be very important for lowering vehicle operating costs, conserving fossil fuel resources, and reduction of CO2 (greenhouse gas) levels. This paper presents a detailed review of a quiescent combustion system for a heavy–duty diesel engine, which offers breakthrough performance in terms of the exhaust emissions – fuel consumption trade–off, compared with the more conventional swirl supported combustion system. This conclusion is supported by experimental results comparing quiescent and swirl supported versions of various combustion system configurations.
Technical Paper

Emulating the Behavior of Truck Drivers in the Longitudinal Control of Headway

1999-11-15
1999-01-3706
This paper describes control system and psychological concepts enabling the development of a simulation model suitable for use in emulating driver performance in situations involving the longitudinal control of the distance and headway-time to a preceding vehicle. The developed model has mathematical expressions and relationships pertaining to the driver's skill in operating the brake and accelerator (“inverse dynamics”) and the driver's perceptual and decision-making capabilities (“desired dynamics”). Simulation results for driving situations involving braking and accelerating are presented to aid in understanding the research work.
Technical Paper

Measurement and Analysis of Commercial Vehicle Air Dryer Efficiency

1999-11-15
1999-01-3774
The measurement of pressure dew point is a well-known method of describing air quality, however this value seldom assists commercial vehicle OEM’s and operators in establishing specific air drying requirements for their vehicles. This paper describes the method and examines the results of using the dryer capacity method specified in SAE document J2384, section 5.2, for determining air dryer performance, and compares the results of various air-drying techniques and the impact on vehicle system design to give the most efficient solution. The paper further goes on to discuss how the drying capacity can also be influenced by the design of the air dryer to meet a wide range of vehicle applications both in Europe and North America. Since J2384 excludes continuous flow air dryers from the scope of the document, they will likewise be excluded from discussion here.
Technical Paper

Steering Performance Evaluation - Heavy-Duty Highway Tractor Wander Test

1999-11-15
1999-01-3764
Heavy-duty highway tractors are the topic of various studies and tests to understand vehicle wander as a contributing factor to driver fatigue. Subtle variations in steering system characteristics can create measurable differences in performance, and operators may have different subjective opinions of the same system. This paper's purpose is to examine wander test setup and data analysis for tests conducted on an International® Model 9200 tractor-trailer at the Navistar Technology and Engineering Center in Fort Wayne, Indiana. Instrumented data and subjective ratings were collected using five power steering gears, evaluated by six drivers, operating over a specific test route.
Technical Paper

Electronic Compressor and Air Dryer Control

1999-11-15
1999-01-3771
The paper details opportunities for electronic control of the pneumatic charging system of an air braked vehicle. Electronic control of the charging and drying functions can result in increased fuel efficiency and improved air quality. Control functions can be used to identify and warn of in-service issues, provide prioritized system charging for faster drive-away, and signal required preventative maintenance. The first portion of the paper describes current industry practice, as well as common issues that can result from those practices. This is followed by presentation of areas of improvement, where specialized control features result in energy savings, air quality increases and maintenance/downtime savings. This portion will focus on adaptive control of components used today, and will briefly discuss opportunities for the next generation of charging system devices. The final section of the paper presents the control logic and vehicle interface allowing for system integration.
Technical Paper

How Diagnostics Contribute to Vehicle Productivity and Driver Retention

1999-11-15
1999-01-3751
This paper begins with an outline of the cost structure of operating a commercial vehicle. The focus is on maintenance costs and how diagnostics and prognostics can lower costs. The paper then describes a link between vehicle productivity, driver productivity and driver satisfaction. Examples of onboard and offboard diagnostic systems will be used to illustrate how users create a vehicle that is “the best place to work” for drivers.
Technical Paper

INNOVATIVE ELECTRONICS A Key to Safety, Driver Retention, and Customer Service

1999-11-15
1999-01-3750
The following information is intended to provide a front line perspective of what benefits have been realized in safety, driver acceptance, and customer service, given the level of technology available to the medium and heavy duty truck and bus industry today. It does not specifically address the manner or method of technology utilized for such achievement, moreover it addresses the enhancements that specific components have made possible. Personal experiences are presented to support the benefits and a wish list of the latest technology available concludes this presentation.
Technical Paper

High-Level In-Vehicle Decision Support

1999-11-15
1999-01-3752
This paper documents the current realities of in-vehicle navigation systems in terms of their functionality, scope and responsiveness. It discusses the evolution of these systems with the advent of wireless communications. Addressed are the issues associated with delivery and utilization of real-time traffic, incident, and weather information to and by in-vehicle navigation systems. Also discussed are other High-level in-vehicle decisions that can be supported by the marriage of wireless communications with in-vehicle navigation. Applications considered range from the choosing of alternate waypoints and destinations (where to get gas, where to park), to the host of nRouteCommerce transactions that can be more efficiently achieved with the support of in-vehicle navigation (reserving a parking space, resetting household thermostats as you approach home). Implications on driver workload, in-vehicle processing, wireless bandwidth and Internet traffic are discussed.
Technical Paper

A Three Year Comparison of Natural Gas and Diesel Transit Buses

1999-11-15
1999-01-3738
This report details the experiences of two California public transit agencies that replaced aging diesel buses with new compressed natural gas (CNG) buses in 1994. The operating characteristics and costs of 170 natural gas buses are compared with 73 older diesel buses. The natural gas bus fleets have operated well and led to cost reductions in both fleets. The findings are particularly significant because both Sacramento Regional Transit District (RT) and SunLine Transit Agency have been using the same engine-chassis configuration, thus enabling a valid method to combine cost data for a large sample fleet of buses. The data indicate that labor for diesel equipment was almost twice that for CNG vehicles, parts were 25% more and fuel costs were nearly double. In 1997, CNG buses saved RT over $1 million in fuel, maintenance, parts and hazardous waste disposal, a 38% per mile reduction over the cost of their older diesel buses.
Technical Paper

Ergonomic Designs of Mercedes-Benz Trucks at DaimlerChrysler

1999-11-15
1999-01-3736
This paper describes the procedure used to ensure that new trucks of the brand Mercedes-Benz meet the ergonomic requirements of all drivers, using the example of the semitrailer. Mercedes-Benz trucks are sold in different countries. Because of this, varying legal requirements, different sizes of drivers and different lifestyles and habits have to be considered. To solve this problem perfectly, new methods and tools have been acquired, resulting in increasing optimization of the process of truck development.
Technical Paper

Using Modern Technology to Improve Truck Seating

1999-11-15
1999-01-3735
Many advancements have been made through the use of technology that give seat manufacturers the capability to provide greatly improved truck seats. Until recently the design and development of new seating was accomplished primarily through static surveys. Modern technologies available today will reduce cost, development time, and the overall effort associated with utilizing real people to develop a seating project. In many instances when these seats were placed into vehicles with actual truck drivers riding in them for many hours a day, the drivers inputs resulted in multiple revisions to the original seat to satisfy their comfort issues. With modern technologies such as computer generated seat modeling, pressure mapping, and our state of the art test equipment such as a six–axis ride simulator, it has become part of any new seat development program to acquire field ride data in specific trucks and duplicate these inputs in the test laboratory.
Technical Paper

Urea-SCR System Demonstration and Evaluation for Heavy-Duty Diesel Trucks

1999-11-15
1999-01-3722
The Institute of Transportation Studies at the University of California, Davis (ITS-Davis) has brought together a group of public and industrial partners to demonstrate and evaluate the Siemens-Westinghouse Urea-Selective Catalyst Reduction System (SINOx™). The SINOx System has the potential to generate major reductions in nitrogen oxides (NOx) and the volatile organic fraction (VOF) of particulate (PM) from heavy-duty diesel engines, without increasing fuel consumption and carbon dioxide (CO2) emissions. This demonstration began with engine bench testing at Detroit Diesel Corporation to calibrate the system to attain 1 g/bhp-hr NOx emissions in the transient portion of the US-FTP on a 1999 Series 60 engine that has a 4 g/bhp-hr emission level. The second phase of the project entails an on-highway demonstration of a set of ten, Freightliner Class 8 heavy-duty diesel vehicles. These vehicles are part of the Valley Material Transport fleet based in French Camp, California.
Technical Paper

Optimal Suspension Damping for Improved Driver- and Road- Friendliness of Urban Buses

1999-11-15
1999-01-3728
Dynamic interactions of urban buses with urban roads are investigated in view of the vibration environment for the driver and dynamic tire forces transmitted to the roads. The static and dynamic properties of suspension component and tires are characterized in the laboratory over a wide range of operating conditions. The measured data is used to derive nonlinear models of the suspension component, and a tire model as a function of the normal load and inflation pressure. The component models are integrated to study the vertical and roll dynamics of front and rear axles of the conventional and modern low floor designs of urban buses. The resulting nonlinear vehicle models are thoroughly validated using the fieldmeasured data on the ride vibration and tire force response of the buses.
Technical Paper

Investigation of Wheeled Tractors Ride Comfort Using Hydraulic Semi-Active Suspension System

1999-11-15
1999-01-3727
In this paper, an electronically controlled hydraulic semiactive system for the seat suspension of wheeled tractors is theoretically designed to improve the driver ride comfort. Using a three degrees of freedom mathematical model, the damping force controller is designed based on optimal control theory and Nelder / Mead Simplex minimization method to perform a limited state feedback information. The controller considers the damping constraint which adapts the actual damping between the prescribed limits. The model results are generated when excited by a statistically random road profile. The results are presented in time and frequency domains. The driver vertical acceleration for semi-active and conventional passive systems are compared at similar root mean square (r.m.s) value of suspension working space. The semiactive system achieved a significant improvement, 18 percent, over the passive system with no power requirement from the tractor engine.
Technical Paper

Simultaneous Visualisation of Spray and Flame Propagation in a Heavy-Duty Transparent-Engine with Common-Rail Injection System

2000-06-19
2000-01-1797
The transport of goods is mainly realised by the use of heavy-duty vehicles equipped with diesel engines as a drive assembly. Considering the high flexibility and reliability as well as the growing interest in saving environmental resources, a further optimisation of DI-diesel engines regarding fuel consumption and exhaust emissions is necessary. Current discussions on the application of different injection systems for passenger cars (distributor pump, common-rail, …) are also of great significance with regard to heavy-duty vehicles. Optical measurement techniques are a valuable tool to evaluate the quality and the potential of modern DI-diesel injection systems. In this work a conventional heavy-duty engine (MAN) was modified to carry out optical investigations inside the combustion bowl, concerning spray propagation and flame luminosity for different injection nozzles. With respect to the current discussions, it was equipped with a modern common-rail system.
Technical Paper

Relative Impact on Environment and Health from the Introduction of Low Emission City Buses in Sweden

2000-06-19
2000-01-1882
This paper is focusing on the technical measures that have been implemented during the last decade to reduce the emissions from heavy-duty buses in Sweden. The emission tests carried out on these buses have been evaluated in order to assess the impact on the environment and on several health effects from switching to improved technology and to alternative fuels. Emission factors for the most important emission components (regulated and unregulated) have been determined for each option. Several effects from the emission components have been calculated using weighting factors for each component. Acidification, eutrophication, ozone forming potential, cancer risk, greenhouse gases and several other effects have been evaluated. The analysis showed considerable improvements by reformulation of the diesel fuel and by fitting aftertreatment devices. Particulate emissions and its effects are probably the most severe emission component from the diesel engines.
X