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A detailed analysis has been made on the Cetane Scale presently used to rate the autoignition quality of fuels. The effect of the increase in temperature and pressure, as a result of increasing the compression ratio, on the ignition delay has been theoretically and experimentally analyzed. It has been found that the ignition delay is more sensitive to air temperature than air pressure. The sensitivity increases with the drop in the cetane number of the fuel. Many techniques have been examined to modify the present cetane scale. A modified scale has been developed by raising the inlet temperature from 150°F to 350°F without changing the rest of the rating technique. The modified scale is very effective in extending the scale to zero cetane number and is able to rate the low ignition quality fuels.

When vehicle exhaust emission tests or vehicle fuel consumption measurements are performed on a chassis dynamometer, the dynamometer is usually adjusted to simulate the road experience of the vehicle. In this study, road load versus speed data were obtained from 64 light-duty vehicles. Dynamometer power absorption settings to simulate the measured road loads are computed. These dynamometer settings are regressed against vehicle frontal area and vehicle inertia weight. It is concluded that the dynamometer load settings are most accurately predicted on the basis of the vehicle frontal area. The frontal area based prediction system is then improved by separating vehicles into different classes and by including estimations of the effects of the vehicle protuberances.

Data from dynamometer tests is presented which shows the fuel consumption penalty when emission requirements constrain air-fuel ratio to near stoichiometric mixtures. This was verified on one vehicle.

A simple model of the energy required to negotiate the two Federal test cycles is described and then used as a bssis for a graphic representation of the relative energy consumption. The utility of the concept is demonstrated by comparing certification fuel economy data and projections with the aid of the relative energy consumption plot.

The potential fuel economy and exhaust emission benefits that might be obtained by smoothing the flow of traffic have been investigated. Substantial improvements in fuel economy and reductions in exhaust emissions are possible if the flow of traffic is smoothed. Traveling during the smooth flow conditions of the early morning (4 am) as compared to travel on the same urban route during highly congested flow (5 pm rush hour) resulted in a fuel economy improvement of 31% for hot-starts and 35% for cold-starts. Also, traveling during smooth flow conditions resulted in reductions in HC, CO, and NOx emission levels of 54%, 52%, and 2% respectively for hot-starts and 35%, 52%, and 13% respectively for cold-starts. The reported results were obtained by simulating traffic conditions on a chassis dynamometer.

After 50 years of parallel development and growth, a comparison of safety statistics between U.S. public highways and the General Motors Proving Ground 200 km private road system shows: the Proving Ground has approximately a five times lower accident rate, seven times lower fatality rate, thirty-five times lower injury rate, and almost nine times lower property damage rate. Accident analysis and preventive countermeasures are discussed philosophically and by practical examples. This exceptional safety record has been achieved by having trained drivers operating well-maintained vehicles on properly designed driving schedules using a road/roadside system designed for safety. All known Proving Ground accident causation factors now have operational countermeasures except sleep, and this remains a problem for which solutions are sought. “Progress: There must always be a better way.”*

This paper describes the results of a test program to evaluate various roadway disturbances present in the driving environment. The specific objectives were to pare down the list of possible roadway disturbances to the worst cases, identify handling problem areas, find meaningful response parameters and compare responses of different vehicles which might influence the results. The program provided an accident data analysis, survey questionnaire results and full scale test results which found the pavement/shoulder dropoff (requiring an edge climb maneuver) to be the most severe and most likely disturbance to result in lane exceedance. This occurs when the vehicle is scrubbing one set of tires on the shoulder edge (or encountering the edge at too shallow an angle for climb), thereby climb), thereby requiring the driver to apply a large steering deflection to get the car to climb back onto the pavement. In this case the vehicle will “spin out” if the speed is high enough.

A new Short Test for emission control has been developed, which in short time gives the emission status of a vehicle with very small variability. The principle of this new method is that the vehicle engine is braked against its own inertia forces, in order to reach such pressures and temperatures in the engine that significant quantities of nitrogen oxides, hydrocarbons and carbon oxides will be generated. The method is well correlated to existing emission tests.

The Restorative Maintenance Program conducted by the Environment Protection Agency in late 1976 and early 1977 provides short test and Federal Test Procedure data on a large fleet of relatively new consumer owned automobiles. The program included testing of 300 vehicles in Chicago, Detroit and Washington, D.C. The vehicles that indicated a need for maintenance were repaired and retested by the FTP and the five short tests being considered by the agency for the Federal warranty regulations. These data are examined by conventional regression and correlation methods, contingency table analysis and maintenance effectiveness criteria. The conclusions of the study indicate that while the mathematical correlation coefficients are quite low for most of the tests, all five tests are effective in identifying vehicles in need of maintenance and significant hydrocarbon and carbon monoxide emissions reductions can be achieved at relative low vehicle failure rates.

The floor panel temperature of vehicles conforming to the emission control standards is increased because of heat conducted from the exhaust pipe system to the panel. Therefore, we developed model test equipment and through experimentation obtained the heat resistance temperature for various types of floor coverings. Based on the test results, we estabilished the target floor panel temperature, at which normal floor covering conditions can be maintained, and thus provided effective heat insulation for each specific floor covering.

The effect of fuel hydrocarbon composition on exhaust emissions was determined according to the Japanese statutory cycles for five Japanese vehicles using seven kinds of unleaded fuels. Vehicles used for the tests were conventional internal combustion engine vehicles with - and without - oxidation catalyst and EGR (exhaust gas recirculation), rotary engine vehicles with - and without thermal reactor and a CVCC engine vehicle. Hydrocarbon composition of the seven fuels varied from 10 to 50 vol.% in aromatics and from 0 to 25 vol.% in olefin content. The effect of fuel composition on mass emissions of CO, HC and NOx is of little significance for any of the vehicles tested. The hydrocarbon composition in exhaust gas varies substantially with the fuel composition and emission control system of the vehicles. As the fuel aromatics increase, aromatic content in the exhaust hydrocarbon fraction also increases, but olefin content tends to decrease in all vehicles except the catalyst vehicle.

Exhaust gases from fourteen 1970-4 model and twenty 1975-7 model General Motors cars were collected during 1975-8 Federal Test Procedure tests and analyzed by gas chromatography. Hydrocarbon reactivity was calculated from the chromatographic analyses, using several reactivity scales. The use of oxidation catalytic converters on the 1975-7 model cars greatly changed the exhaust hydrocarbon composition in comparison to 1970-4 model cars. In general, such use caused individual paraffins to increase in carbon percent and individual olefins and acetylene to decrease. For example, the methane carbon percent was 5.0 for 1970-4 model cars (nonconverter cars) and 14.5 for converter cars; ethylene percent was 12.5 for nonconverter cars and 7.4 for converter cars; propylene was 6.5 for nonconverter cars and 2.9 for converter cars; and acetylene was 7.9 for nonconverter cars and 2.2 for converter cars.

Today's fragmentary and heterogeneous regulation regarding vehicle and components, static and dynamic tests, suggest a new trend for a global evaluation of the vehicle by means of collision tests between the vehicle, with dummies on board, and dynamometric deformable moving barrier. Such moving barrier (always the same) is used in the front collision test as well as in side and rear collision tests. The new Fiat Safety Center is designed not only to enable it to carry out the tests required by present regulations, but also with a view to future test trend. Covering 27 acres, the installation provides for any type of test, with 1370-ft tracks giving a terminal speed of 97 mph for cars and 62 mph for trucks of up to 20 Tons. Vehicle are propelled by a two-ton trolley, rolling on angled rails in a culvert below the surface.

Sixty-six diesel-powered taxicabs, paired with an equal number of gasoline powered cabs, are being operated in three taxicab fleets in New York City. Identical cabs are powered either with Chrysler 225 CID gasoline engines or with Nissan 198 CID diesel engines. Data from both sets of cabs are analyzed to determine differences in reliability, maintenance, exhaust emissions and fuel economy. Data currently reported covers a period where individual taxicabs have accumulated between 70,000 and 110,000 miles of service. The diesel fleet shows improvement in fuel economy and exhaust emissions over the gasoline fleet.

This paper discusses information relevant to the impact of the characteristics of gasoline on fuel economy of motor vehicles. In particular, the paper analyzes the impact of the density, volatility, octane rating, and cleanliness of gasoline, as well as the impact of its additives. It also studies the relationship between fuel characteristics, fuel metering, and fuel economy. Furthermore, the paper serves to help explain some of the differences that may be found between the results of the EPA fuel economy tests and the values observed by vehicle owners in normal service. The paper is based on the analysis of the available literature on the subject, as well as on specific information submitted to the EPA by companies engaged in petroleum refining, fuel additives production, and automobile manufacturing.

This paper deals with the various fibers used in nonwoven materials. It describes where and why they are used in automobiles. Included are the history of some products, requirements and test methods of a needled material as well as a glossary of applicable automotive terms. Typical automotive uses are described in more detail. There is also a brief outline of what might be seen in the future from a fiber, manufacturing or application point of view.

Effects of reducing engine oil and rear axle lubricant viscosities on fuel economy were determined in EPA combined City and Highway (EPA 55/45) tests and in road tests, using four different sized cars. In EPA 55/45 tests, fuel economy rating improvements averaged about 1.5 percent; warmed-up and cold-start road test fuel economy improvements averaged about 4 and 8 percent, respectively. For a specific engine oil viscosity reduction, warmed-up road test fuel economy increased with decreasing car mass and power-to-mass ratio. Warmed-up constantspeed fuel economy improvements obtained by lowering only the engine oil viscosity were about the same as those estimated from reductions in engine friction power. However, measured fuel economy improvements with lowviscosity rear axle lubricants were inexplicably higher than those estimated.

A fuel-efficient passenger car engine oil has been developed that showed an average of 4.6% improvement in fuel economy compared with several premium, SAE 10W-40 oils (API Engine Service Classification SE) in a road fleet test. In the combined Environmental Protection Agency city/highway testing, this oil gave 5.5% better fuel economy on average than an SE premium 10W-40 oil. The excellent overall performance of this lubricant was confirmed by ASTM Engine Sequence tests and evaluation in severe taxicab operations. The new 10W-40 oil, which incorporates friction-reducing properties, is formulated with petroleum base stocks and known additives, many of which are conventionally used. It is expected that advances in friction-related technology developed in this work may lead to oils with even higher levels of fuel economy improvement in the future.

In continued studies with full-scale engines on the laboratory dynamometer, the effect of the engine variables air-fuel ratio, ignition timing, and rate of exhaust gas recirculation on octane requirement increase and exhaust emissions was studied in two engines at two compression ratios. A lead-free base gasoline was used in all tests, and a test procedure previously shown to relate well with road tests was followed. In both engines, ignition timing and rate of exhaust gas recirculation were found to have appreciable effects on octane requirement increase. Air-fuel ratio had an effect in one engine but not the other. The effect of compression ratio was mixed.

This paper presents the development of a computer model to simulate fuel usage and emission contributions of the past and future truck and bus population in the United States. The projected future years are beyond 1976 to 1990. The trends in vehicle population growth, yearly miles traveled and ton-miles are also calculated by the model. The model developed is flexible and brings together several technical concepts which reflect recent inputs from industry and government. The formulation of the model is based on a systems approach, in which the several submodels (the "Population," "Mileage," "Fuel Usage," and "Emission") are interrelated. The preliminary quantitative results are discussed to demonstrate the satisfactory performance of the computer model. Increased rates of dieselization are analyzed to determine their effect on reducing fuel consumption and the impact on total emission contributions. The use of the computer model to study an urban area for air quality is discussed.