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Spinal fractures in open cockpit open wheeled racecars have increased in frequency over the past 10 years (7.5% of all racing injuries in 1995 to 18.7% currently). In order to quantitate this and investigate potential causes we collected all fractures occurring in 5 open wheeled series from 1996 to 2005. The ultimate goal of the study is to identify causative factors that can be altered to lessen the fracture risk. This is a multipart study. These fractures were categorized as to fracture type and severity, and correlated to ADR-2 data from the race car. Also used in the analysis were data from a rearward impact barrier test, HYGE sled testing and development of a computer model. (Development of the model is reported in a separate submission) 38 incidents resulted in fractures in 36 different drivers (2 involved in 2 incidents). 54 spinal levels were injured with 9 drivers sustaining injury at more than one level. The thoracic and thoracolumbar spine was involved most frequently.

Portable systems capable of measuring mass exhaust emissions while riding on-board vehicles and mobile equipment are relatively new. Their advantages include lower measurement costs, the ability to measure emissions under realistic operating conditions (including conditions that are difficult to simulate in the laboratory), the ability to measure emissions where no traditional laboratory is available, and applicability to a broader range of engines and vehicles than those addressed by traditional laboratory methods (e.g. construction machinery). However, on-board methods have not yet been fully accepted in the air quality community. This is due in part to concerns over their reproducibility and accuracy, and the adequacy of the corresponding quality assurance and quality control measures.

Emissions of particulate matter (PM) and oxides of nitrogen (NOx) from heavy-duty engines used in road vehicles and mobile equipment are of critical concern to air quality planners. Accurate measurement of these emissions is needed both for emission inventory purposes and for the development and validation of emission control measures. These emissions cannot adequately be predicted from laboratory tests on new engines. This paper reports the development of the Ride-Along Vehicle Emission Measurement (RAVEM) system. Based on the constant volume sampling (CVS) principle, the RAVEM system can accurately and repeatably measure mass emissions of NOx, CO2, and PM from an engine exhaust pipe while “riding along” on the vehicle or equipment under test. In most cases, this can be done without removing the vehicle from service. RAVEM test results have been shown to correlate very closely with those of conventional CVS emission laboratories.

Emissions from heavy-duty vehicles in real operation on the road often differ greatly from those that would be projected from laboratory testing. Reasons for this difference include variations between laboratory and real-world driving conditions, wear and deterioration that are not effectively modeled by laboratory tests, inadequate or inappropriate in-use maintenance, and the use of “cycle-beating” strategies and “defeat devices” by engine manufacturers. This paper analyzes data showing in-use emissions from heavy-duty diesel and natural gas vehicles tested using various driving cycles on chassis dynamometers. It is shown that average in-use emissions of particulate matter (PM) and oxides of nitrogen (NOx) from late model heavy-duty diesel engines are much higher than predicted by current emission models, and greatly exceed the emission standards to which these engines were certified.

The standard procedure for determining non-methane hydrocarbon (NMHC) emissions is to subtract measured methane emissions from total hydrocarbon emissions measured by flame ionization detector. The results of this method were compared to the results of direct GC speciation of hydrocarbon emissions. For gasoline vehicles using an all-hydrocarbon fuel, the two methods demonstrate nearly perfect correlation, with a linear regression coefficient near 1.0, and R2 = 0.999. The correlation using reformulated gasoline is only slightly worse. For natural gas vehicles, however, the correlation was poor, with R2 < 0.30. This poor correlation is attributed to the high methane content of natural gas, which results in NMHC emissions being very low compared to the level of methane. Both the total hydrocarbon and methane measurements contain some error, and the resulting combined error in the NMHC concentration is of the same order as the concentration itself.

This paper summarizes a review of dual-fuel natural gas/diesel engine technology carried out for the Gas Research Institute.(1)* In the past, dual-fuel natural gas/diesel engines have been relegated to a few small niche markets, but our review has shown that dual-fuel engine technology has significant potential. Potential advantages of dual-fuel engines include diesel-like efficiency and brake mean effective pressure (BMEP) with much lower emissions of oxides of nitrogen (NOx) and particulate matter. New technologies offer solutions to the problems of poor efficiency and emissions at light load. Dual-fuel engines can be designed to operate interchangeably on natural gas with a diesel pilot, or on 100% diesel fuel. Many existing diesels can be converted to dual-fuel operation.

This paper reports some results from a study of emissions control for railway locomotives performed for the California Air Resources Board.(1)* Feasible and cost-effective control techniques for locomotive emissions include retarding injection timing and other engine modifications, selective catalytic reduction (SCR), use of liquified natural gas (LNG) fuel with low-emission dual-fuel or spark-ignition (SI) natural gas engines, LNG combined with SCR, and electrification. Use of a combination of dual-fuel and SI LNG engines could reduce locomotive NOx emissions by 80%, at a cost of less than $1,100 per ton of NOx eliminated. SCR added to diesel and LNG could produce NOx emission reductions of 90 and 97 %, respectively, at costs less than $3,300 per ton. All of these technologies could be retrofit to existing diesel locomotives.

Natural gas has considerable potential as a “clean” fuel for motor vehicles. This paper reviews the present state of the art in natural gas vehicles, focusing on engine technology and emissions. Natural gas engines generally show very low emissions of reactive hydrocarbons, carbon monoxide, and particulate matter, but NOx emissions can be fairly high. Approaches to NOx control include stoichiometric operation using a three-way catalyst and air-fuel ratio feedback, and “lean-burn/fast-burn” engines with NOx controlled through reduced flame temperature. Engines of both types have demonstrated excellent emissions performance - exceeding U.S. 1994 emissions requirements for heavy-duty engines. Optimized natural gas engines are significantly more efficient than present gasoline engines, with lean-burn natural gas engines approaching diesel efficiency.

A study has been conducted of the feasibility, costs, and emissions benefits of a number of alternative-fuel and conventional technologies for controlling emissions from Diesel transit buses in the city of Santiago, Chile. Alternative fuels considered were methanol, compressed natural gas (CNG), and propane - using a variety of engine technologies. These were compared with each other and with conventional emission control approaches - an existing inspection/maintenance program, particulate trap-oxidizers, and low-emission Diesel engines. Cost estimates were developed for both new buses and retrofit of existing buses. Use of a consistent analytical framework and assumptions across all of the technologies allowed realistic comparisons between them. Overall, trapoxidizers and compressed natural gas in a lean-burn, converted Diesel engine provided the best combinations of cost and emissions reduction.

Diesel engines in mobile off-highway applications include those used in railway locomotives, marine vessels, farm equipment, construction and industrial equipment, and mobile refrigeration. Engines in these five classes are responsible for about one-third of all mobile diesel emissions (highway vehicles account for nearly all of the rest). Emissions from these engines are not presently subject to regulation. This paper presents estimates of emission factors and nationwide emissions inventories for each of these equipment classes. Estimates of achievable emissions levels, the technologies required to achieve them, and the cost-effectiveness of emissions control for each class are also presented. Emissions test procedures and recommended regulatory approaches for controlling off-highway diesel emissions are discussed as well.

This paper reports the results of Phase I of a study of heavy-duty diesel inspection and maintenance (I&M). Heavy-duty diesel vehicles have generally been exempted from I&M programs, due to the lack of a suitable inspection procedure and uncertainty as to the reduction in excess emissions which might result. This paper describes common types of tampering and malmaintenance which can lead to excess emissions from heavy-duty diesel trucks and buses, and presents the results of two surveys aimed at estimating the frequency of occurrence of these problems. Data showing the effects of some of these problems on engine emissions are also presented. Finally, a preliminary estimate of the impact of excess emissions from diesel trucks and -buses in California is presented. Further work to develop suitable inspection procedures and to evaluate the costs and benefits of alternative I&M programs is being performed in Phases II and III of the project.

Recent regulatory attention has focussed on reducing the emissions from new heavy-duty diesel vehicles. Stringent new NOx and particulate emissions standards will go into effect in 1988 and 1991. The long lifetimes of heavy-duty trucks and buses, the high levels of emissions per vehicle, and the acute particulate problems in many cities all argue that retrofitting emission controls to existing vehicles should be considered as well. This paper presents a preliminary evaluation of eight potential diesel retrofit technologies (considered as any technique for reducing emissions from existing vehicles). Technologies considered were (in order of their apparent promise): diesel fuel modifications, trap-oxidizers, conversion to methanol fuel, particle agglomerators, fumigation with LPG, vertical exhausts, special-purpose fuel additives, and high-altitude adjustments/kits. The technical feasibility, emissions benefits, approximate cost, and cost-effectiveness of each technique are discussed.

The U.S. Environmental Protection Agency has recently reduced the permissible concentration of lead in gasoline from 1.1 to 0.1 gram per gallon, and has proposed to eliminate lead entirely by 1988. In addition to its octane-enhancing properties, lead in gasoline protects exhaust valve seats in older engines from undue wear (“valve-seat recession), and it and its scavengers have numerous other positive and negative effects. These include changes in octane requirements, hydrocarbon emissions, engine rusting, corrosive wear, oil thickening and degradation, spark-plug fouling, exhaust-valve burning, and exhaust system corrosion. This paper reviews the literature on the harmful and beneficial effects of lead and lead scavengers on engines, and examines some of the substantial body of operating experience that has been accumulated with unleaded gasoline in older engines.

Diesel engines in light and heavy-duty vehicles emit significant amounts of oxides of nitrogen (NOx), particulate matter, sulfur oxides, and unburned hydrocarbons. Emissions of these pollutants are strongly affected by the quality and composition of the diesel fuel used. This report reviews the published literature concerning fuel effects on diesel emissions, and examines the feasibility, costs, and cost-effectiveness of reducing diesel emissions by means of changes in diesel fuel composition. Two specific changes are considered: a drastic reduction in diesel fuel sulfur content; and the same sulfur reduction along with a moderate reduction in the aromatic hydrocarbon content. The effects of each change on engine durability, fuel economy, and refining costs are considered together with the emissions effects. The results indicate that the cost of producing low-sulfur diesel fuel would be more than offset by savings in reduced maintenance and greater engine life.

Heavy-Duty diesel particulate emissions are presently the subjects of considerable regulatory concern. The U.S. Environmental Protection Agency (EPA) has proposed particulate standards for heavy-duty diesel truck and bus engines. As a result, particulate control technology for heavy-duty diesels is of increasing interest. This paper presents some preliminary findings from a current study of particulate control for heavy-duty diesel engines. It surveys the present state of the technology, with particular attention to trap-oxidizers. The special requirements for trap-oxidizers in heavy-duty service are described, and the problems in adapting the trap-oxidizer technologies developed for light-duty diesels to heavy-duty engines are discussed. Cost estimates for potential heavy-duty fuel-oxidizer systems are developed. The paper also briefly discusses the potential for in-cylinder control of NOx and particulates, and the trade-off between NOx and particulate emissions.