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Exhaust emissions from heavy-duty diesel engines operating at high altitude are of concern. EPA and Colorado Department of Health sponsored this project to characterize regulated and selected unregulated emissions from a naturally-aspirated Caterpillar 3208 and a turbocharged Cummins NTCC-350 diesel engine at both low altitude and simulated high attitude conditions (≈ 6000 ft). Emissions testing was performed over cold- and hot-start transient Heavy-Duty-Federal Test Procedure (HD-FTP) cycles as well as selected steady-state modes. In addition, the turbocharged engine was operated with mechanically variable and (fixed) retarded fuel injection timing to represent “normal” and “malfunction” conditions, respectively. High altitude operation generally reduced NOx emissions about 10 percent for both engines.

Several properties of a refinery “straightrun kerosene“, which had a narrow boiling range approximating the middle of a No. 1 diesel fuel, were altered to study their effects on regulated and unregulated exhaust emissions. Eleven fuel blends, representing changes in nitrogen content, aromatic level, boiling point distribution, olefin content, and cetane number, were evaluated in a 1975 Mercedes-Benz 240D. Statistical analysis, including regression, was performed using selected fuel properties as independent variables. Higher aromatic levels were generally associated with increased emissions, while increased olefin levels were generally associated with decreased emissions.

This paper summarizes an investigation of reductions in exhaust emission levels attainable using various techniques appropriate to gasoline engines used in vehicles over 14,000 lbs GVW. Of the eight gasoline engines investigated, two were evaluated parametrically resulting in an oxidation and reduction catalyst “best combination” configuration. Four of the engines were evaluated in an EGR plus oxidation catalyst configuration, and two involved only baseline tests. Test procedures used in evaluating the six “best combination” configurations include: three engine emission test procedures using an engine dynamometer, a determination of vehicle driveability, and two vehicle emission test procedures using a chassis dynamometer. Dramatic reductions in emissions were attained with the catalyst “best combination” configurations. Engine durability, however, was not investigated.

This paper summarizes a laboratory effort toward reducing nine-mode cycle composite emissions and fuel consumption in a heavy-duty gasoline engine, while retaining current durability performance. Evaluations involved standard carburetors, a Dresserator inductor, a Bendix electronic fuel injection system, exhaust manifold thermal reactors, and exhaust gas recirculation, along with other components and engine operating parameters. A system consisting of electronic fuel injection, thermal reactors with air injection and exhaust gas recirculation, was assembled which met specified project goals. An oxidation catalyst was included as an add-on during the service accumulation demonstration. In addition, the driveability of this engine configuration was demonstrated.

Particulate and gaseous emissions from two light-duty diesel vehicles were measured over eight operating schedules, using five different fuels. Characterization included regulated exhaust emissions and a number of unregulated constituents. Non-routine gas measurements included phenols, hydrocarbon boiling range, and aldehydes. Particulate characterization included mass rates and concentrations, visible smoke, aerodynamic sizing, total organics, BaP, sulfate, phenols, trace elements, and major elements. Statistical analysis of emissions data was undertaken using fuel properties and operating schedule statistics as independent variables. Regressions were computed for a few variables, and analysis of variance and multiple comparisons were used where the data were not suitable for regression analysis.

This paper summarizes a laboratory effort to characterize exhaust emissions from non-catalyst and oxidation catalyst-equipped gasoline automobiles operating under malfunction conditions. One non-catalyst and four catalyst automobiles were evaluated over three test cycles in an unmodified configuration and in four engine and/or emission control system malfunction configurations. Exhaust emission constituents measured, in addition to the currently regulated automobile emissions, include: particulates, sulfates, aldehydes, sulfides, amines, metals, and several additional elements and compounds.

This paper summarizes two laboratory efforts to characterize exhaust emissions from three-way catalyst-equipped gasoline automobiles operating under malfunction conditions. Four automobiles were evaluated over three test cycles in an unmodified configuration and in four engines and/or emission control system malfunction configurations. Exhaust emission constituents measured, in addition to the currently regulated automobile emissions, include: particulates, sulfates, aldehydes, sulfides, amines, metals, and several additional elements and compounds.

Emissions from two heavy-duty four stroke direct injection engines designed to use methanol fuel, one using Diesel pilot fuel injection and the other using spark ignition, were characterized in this program along with those from a comparably-sized Diesel engine. Emissions evaluated during both steady-state and transient FTP procedures included regulated gases (HC, CO, and NOx), unburned methanol, aldehydes, other gaseous organics, total particulate, sulfate, soluble organics in particulate and BaP. The engines adapted for methanol fuel and using catalysts emitted less HC, CO, particulate, soluble organics, and BaP than the Diesel fueled engine.

This paper describes the characterization of regulated and unregulated exhaust emissions from two methanol-fueled automobiles. For comparison, two gasoline-fueled automobiles of the same make and model were also evaluated. These automobiles were evaluated over the Light-Duty Federal Test Procedure and the Highway Fuel Economy Driving Schedule. Additional evaluations with the methanol-fueled automobiles were conducted using promoted base metal catalysts, and one of these automobiles was tested in a non-catalyst configuration. Exhaust constiuents sampled for, in addition to the regulated emissions, include: aldehydes, particulate, individual hydrocarbons, methanol, ethanol, ammonia, cyanide, amines, nitrosamines, and methyl nitrite.

Methods for particulate (and associated organics) emissions control were evaluated in several diesel cars. Of the methods investigated, only “particulate traps” provided large reductions in particulate emissions. Traps evaluated included metal mesh and ceramic monolithic configurations, catalyzed and uncatalyzed. One of the cars, with a ceramic trap installed, completed fifty thousand miles of distance accumulation. No significant deterioration of emissions occurred over those fifty thousand miles.

Several alternate source diesel test fuels were studied to note their effects on regulated and unregulated exhaust emissions from a 1980 Volkswagen Rabbit. Nine fuel blends were tested, including a No. 2 petroleum diesel as base, base plus coal-derived liquids (via SRC-II and EDS processes), shale oil diesel and jet fuel, and other blends of coal-derived liquids, shale oil liquids, and petroleum stocks. Analyses performed include gaseous hydrocarbons, CO, NOx, particulate mass, phenols, smoke, odor, Ames tests, BaP, and polarity profiles by HPLC. Smoke and particulate increases were generally associated with use of coal-derived liquids.

Researchers in the nitrosamine field were contacted on their views of the TEA analyzer and the ThermoSorb/N Air Sampler for nitrosamine analysis. Fifty-eight vehicle interiors were sampled to determine the effects of vehicle type, vehicle age, mode of operation, and ambient conditions on interior nitrosamines. Nitrosamines were found in passenger cars, station-wagons, passenger and cargo vans, pickup trucks, and in new and used heavy-duty trucks, but not in motor homes. The average daily intake of nitrosamines from vehicle interiors for a commuter in a vehicle 3 hours/day was estimated to be less than that from a can of beer or from a strip of bacon.

Emissions from a modern heavy-duty Diesel truck engine were characterized with five different fuels during transient and steady-state operation. A control fuel (Phillips D-2) was used for baseline emissions, and as base stock in three alternate fuel blends containing EDS or SRC-II middle distillates, or used lubricating oil. The fifth fuel tested was neat soybean oil, heated to 145°C. HC, CO, NOX, and particulate emissions were similar for this engine on all fuels tested, with the exception of higher particulates for the soybean oil and higher NOX for the SRC-II blend.

Exhaust emission data from several fuel effects studies were normalized and subjected to statistical analyses. The goal of this work was to determine whether emission effects of property variation in alternate-source fuels were similar, less pronounced, or more pronounced than the effects of property variation in petroleum fuels. A literature search was conducted, reviewing hundreds of studies and finally selecting nine which dealt with fuel property effects on emissions. From these studies, 15 test cases were reported. Due to the wide variety of vehicles, fuels, test cycles, and measurement techniques used in the studies, a method to relate them all in terms of general trends was developed. Statistics and methods used included bivariate correlation coefficients, regression analysis, scattergrams and goodness-of-fit determinations.

Diesel soot or smoke has been regarded as a nuisance pollutant and potential health hazard, especially in congested urban areas where diesel buses operate. Exhaust emissions from a DDAD 6V-71 coach engine and a similarly-powered 1980 GMC RTS-II coach, fitted with a non-catalyzed particulate trap, were characterized over various Federal Test Procedures for heavy-duty engines, including an experimental test cycle for buses. Regeneration was accomplished using an in-line burner in the exhaust to raise the engines' idle exhaust gas temperature from 120 to 700°C. Trap testing included approximately 15 hours of engine operation and 100 miles of bus operation. Particulate emissions were reduced by an average of 79 percent and smoke emissions were nil using the trap. The effect of the trap on regulated and other unregulated emissions was generally minimal.

Appropriate chassis dynamometer simulation of road power for truck tractor-trailers and buses were required for emissions evaluations. To establish such simulations, the power required to operate vehicles over a roadway (speed-power relationship) was determined for two truck tractor-trailers and one city bus. Results of these determinations, along with data reported in the literature, were used to determine the power to be absorbed by a chassis dynamometer to simulate On-road driving of trucks and buses. The chassis dynamometer is being used in the subsequent phases of this study involving emissions evaluations of heavy duty vehicles. THE PURPOSE OF THIS PAPER is to describe the findings associated with road power determination and simulation for heavy-duty trucks and buses. Included is a general discussion of road power, along with the results of evaluations on the road and on the chassis dynamometer.

Diesel engines are adjusted to manufacturers' specifications when produced and placed in service, but varying degrees of maintenance and wear can cause changes in engine performance and exhaust emissions. Maladjustments were made on two heavy-duty diesel engines typically used in buses in an effort to simulate some degree of wear and/or lack of maintenance. Emissions were characterized over steady-state and transient engine operation, in both baseline and maladjusted configurations. Selected maladjustments of the Cummins VTB-903 substantially increased HC, smoke and particulate emission levels. Maladjustments of the Detroit Diesel 6V-71 coach engine resulted in lower HC and NOX emission levels, but higher CO emissions, smoke, and particulate.

This paper reviews the use of additives to improve safety aspects associated with the use of methanol as a motor fuel. A survey of the literature was conducted to determine candidate additives for methanol that produce one or more of the following properties: provide a visible or luminous flame, reduce the potential for skin contact, give a foul or unpleasant taste and odor, and act as an emetic. Candidate additives were reviewed to determine potential effectiveness, cost, east of production, health problems, and effects on vehicle performance. Potential additives include complex hydrocarbon mixtures such as gasoline, alcohol soluble dyes and unpalatable compounds such as denatonium benzoate.

The advent of diesel-powered versions of production passenger cars signals significant dieselization in the United States. Two vehicles, an experimental Oldsmobile diesel Cutlass and a Volkswagen diesel-powered Rabbit, were evaluated to determine their gaseous, particulate, smoke, odor, and noise emissions. For comparison, a 1977 Oldsmobile Cutlass powered by the 260 CID gasoline engine and a 1.6 liter gasoline fuel injected Volkswagen Rabbit (Calfornia version) were similarly evaluated under most emission categories. Three transient driving cycles were employed including those used in emissions certification, sulfate testing, and highway fuel economy.

Methods for measurement and expression of crankcase or “blowby” emissions from diesels were developed and demonstrated on a test engine. These methods were subsequently used to characterize gas and particulate emissions from two in-service engines. Crankcase emissions were evaluated under engine operating conditions corresponding to the EPA 13-mode certification test. Substances for which analyses were conducted included regulated pollutants, sulfate, trace elements, nitrosamines, individual hydrocarbons, and aldehydes. Emissions from the diesel crankcases were compared to exhaust emissions (where possible) to assess their importance. Analysis for nitrosamines was continued beyond the original effort, utilizing another test engine.