Ralph C. Stahman

Emissions and Economy of Four Diesel Cars

Four diesel-powered passenger cars were subjected to a wide variety of emission and economy evaluations, and the results are presented in this paper. Tailpipe emissions were measured for gaseous emissions, fuel economy (carbon balance and gravimetric) and smoke. Smoke and gaseous emissions were also measured by chassis dynamometer. Odor and related instrumental-chemical measurements were made. Noise measurements were taken during SAE driveby and a variety of interior-exterior conditions. The results are compared by category to each other, Federal limits, and to test results obtained by EPA laboratories.

Effects of Hydrocarbon to Oxides of Nitrogen Ratios on Irradiated Auto Exhaust, Part 1

Experimental atmospheres consisting of 3 to 12 ppM hydrocarbons and 0.25 to 2 ppM NO/sub x/ were irradiated (uv). Increase in hydrocarbon yielded greater NO/sub 2/ formation. A greater HC/NO/sub x/ ratio produced more oxidants. Eye irritation was greatest at 1 ppM NO/sub x/ and increasing HC.

Removal of Exhaust Particulate from a Mercedes 300D Diesel Car

The problem with diesel exhaust particulate is that it is too-small, too-light, and there is too-much of it. A series of experiments are described that investigate the potential of using an alumina-coated steel wool media, for agglomeration, and an advanced design inertia separator, for collection of the particulate from a 1975 Mercedes 300D diesel car. The goal of 50% reduction was realized when new. The effects on other emissions, performance, and noise were evaluated and durability defined.

Diesel Car Emissions - Emphasis on Particulate and Sulfate

Five diesel-powered, light-duty vehicles, a Peugeot 204D, a Mercedes 240D, and a Perkins 6-247 powered IH pickup, were used to quantify the range of particulate, sulfate as well as other unregulated emissions of odor, visible smoke, sulfur dioxide, aldehydes, and selected non-reactive hydrocarbons. Three transient driving cycles were employed. Emission rates of particulate, sulfate, and other contaminants of a regulated and unregulated nature are presented in several ways: mass per unit of time, per unit of fuel consumed, and per unit of distance driven. Fuel consumption and economy values are also provided. /GMRL/

Dynamic Irradiation Chamber Tests of Automotive Exhaust, Part I

A dynamic irradiation system was used to study the atmospheric photochemical oxidation of dilute automotive exhaust under conditions which simulate atmospheric mixing. The rate on NO/sub 2/ formation increased proportionately with both exhaust concentration and olefin content of the fuel. The percentage of NO/sub 2/ reacting with unreacted fresh exhaust components and with secondary reaction products varied inversely with the increase of the exhaust concentration level. Formaldehyde formation increased in direct proportion to the increase in hydrocarbon concentration at irradiation. Plant effects indicate a shift in the type of phytotoxicant developed and a decrease in damage level with increase in the hydrocarbon concentration level at which the irradiation was made. Bacterial effects showed a significant increase in degree of kill with increase in hydrocarbon concentration level at which the irradiation was made. 8 references, 4 figures, 7 tables.

Federal Air Pollution Efforts, the Early Years

Automobile Emissions were first regulated nation-wide on 1968 models and the Federal activities were shifted to Willow Run and later Ann Arbor, Michigan. The paper deals with the Federal efforts leading to the period of early emissions regulation

Diesel Emission Control Through Retrofits

Exhaust emissions from in-use diesel trucks and buses can be reduced by application of retrofits consisting of new parts and adjustments. The results of fleet test demonstrations of two retrofit kits, one for 2-stroke diesel-powered buses and the other for 4-stroke diesel trucks, are described. Except for the catalytic muffler, the components and adjustments composing the General Motors environmental improvement proposal kit for General Motors city buses were found helpful in reducing exhaust odor, smoke, and certain gaseous emissions. The turbocharger kit and adjustments marketed by Cummins Engine for its NHC 250, an in-use naturally aspirated truck engine, was likewise found to reduce visible smoke satisfactorily. /GMRL/

The Evaluation of Retrofit Devices for the Improvement of Fuel Economy and Emissions

The U.S. Environmental Protection Agency has evaluated and reported on the effectiveness of fuel economy retrofit devices for many years. Originally, such products were marketed as emission improvers but with pressures of the oil embargo in the early 1970s most devices began to be promoted to benefit fuel economy. For the most part, such devices are not effective and do not measure up to the claims made by their advertisers. Of over ninety devices evaluated by EPA, only five have improved fuel economy without increasing emission levels.

Emissions from carbureted and timed port fuel injected engines.

A comparison was made between the exhaust emission characteristics of a popular make car when equipped with the stock carburetor and when equipped with a timed-port fuel injection system. A brief optimization study was made to adjust the spark timing and fuel flow characteristics to minimize emissions. Performance and economy were compared between the fuel injected and carbureted versions. Emission measurements of CO, CO2, and hydrocarbon were made in road tests by proportional sampling and through the California Cycle by continuous nondispersive infra red instrumentation.