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In-cylinder control of particulate emissions in a diesel engine depends on careful control and understanding of the fuel injection and air/fuel mixing process. It is extremely difficult to measure physical parameters of the injection and mixing process in an operating engine, but it is possible to simulate some diesel combustion chamber conditions in a steady flow configuration whose characteristics can be more easily probed. This program created a steady flow environment in which air-flow and injection sprays were characterized under non-combusting conditions, and emissions measurements were made under combusting conditions. A limited test matrix was completed in which the following observations were made. Grid-generated air turbulence decreased particulates, CO, and unburned hydrocarbons, while CO2 and NOx levels were increased. The turbulence accelerated combustion, resulting in more complete combustion and higher temperatures at the measurement location.

A technology demonstration program was conducted by the U.S. Army to verify the feasibility of using aviation turbine fuel JP-8 in all military diesel fuel-consuming ground vehicles and equipment (V/E). Over 2,800 pieces of military equipment participated in a two and one-half year program accumulating over 2,621,000 total miles (4,219,810 km) using JP-8 in combat/tracked, tactical/wheeled, and transportation motor pool vehicles. Over 71,000 hours of operation were accumulated in diesel/turbine engine-driven generator sets using JP-8 fuel. Comparisons of various performance areas with baseline diesel fuel (DF-2) operation were made.

The key words in the marketplace for off-highway vehicles are durability, performance, and efficiency. A manufacturer of these vehicles recognizes that one way to successfully address these needs is by a well thought through electronics design. With the computer sophistication now being incorporated into off-highway vehicles, engineers must work closely to assure electromagnetic compatibility (EMC) of the entire system. A properly established EMC program extending from concept to final design will support each of a product's specified operations and still function as an integrated whole. This paper describes the process for designing the EMC for an off-highway vehicle.

The increased use of diesel-powered equipment in underground mines has prompted interest in reducing their exhaust pollutants. Control of particulate emissions without substantial penalties in other emissions or fuel consumption is necessary. This paper describes test results on a prechaaber, naturally-aspirated, four-cycle diesel engine in which two different concentrations of water-in-fuel emulsions were run. The independent variables comprising the test matrix were fuel, speed, load, injection timing, injection rate, and compression ratio. The dependent variables of the experiment included particulate and gaseous emissions and engine thermal efficiency. Regression analysis was performed on the data to determine how particulate emissions were affected by fuel and engine parameters. Results of this analysis indicated that substantial reductions in particulate emissions could be obtained by utilizing water-in-fuel emulsions.

In this paper, a mathematical model is used to determine the fuel-consuming characteristics of a typical crawler tractor with bulldozer under various opera ting regimes. The results are used to suggest various methods to reduce tractor fuel consumption.

Regulated gaseous, particulate and several unregulated emissions are reported from four heavy-duty diesel engines operated on the chassis version of the 1983 transient procedure. Emissions were obtained from Caterpillar 3208, Mack ENDT 676, Cummins Formula 290 and Detroit Diesel 8V-71 engines with several diesel fuels. A large dilution tunnel (57′ × 46″ ID) was fabricated to allow total exhaust dilution, rather than the double dilution employed in the stationary engine version of the transient procedure. A modal particulate sampler was developed to obtain particulate data from the individual segments of the 1983 transient procedure. The exhaust gas was analyzed for benzo(a)pyrene, metals, N2O, NO2, individual hydrocarbons and HCN. Sequential extractions were performed and measured versus calculated fuel consumptions were obtained.

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.

Five light-duty vehicles were used to investigate HC, CO, and NOx emissions and fuel economy sensitivity to changes in the length of soak period preceding the EPA Urban Dynamometer Driving Schedule (UDDS). Emission tests were conducted following soak periods 10 minutes to 36 hours in length. Each of the first 8 minutes of the driving cycle was studied separately to observe vehicle warm-up. Several engine and fuel system temperatures were monitored during soak and run periods and example trends are illustrated. The extent to which emission rates and fuel consumption are affected by soak period length is discussed.

An experimental sensor array that measures dynamic exhaust temperature and dynamic smoke for the purpose of diagnosing diesel engine fuel injection equipment was designed, built, and tested. The sensor array is portable and easily installed on truck tailpipes, and was tested using two 6V-53 Detroit Diesel engines. The dynamic temperature sensor is a very high response instrument capable of measuring changes in gas temperature in excess of 104°F/second. The dynamic smokemeter is an optical device designed to measure very low levels of light opacity in the smoke plume, with a response compatible with the engine firing frequency. Dynamic exhaust temperature data had more diagnostic significance than dynamic smoke in the detection of maximum power degrading fuel injection faults.

The feasibility of converting a conventional unthrottled 2-stroke diesel engine to gaseous fuel was investigated. The development work was performed in two phases. In phase 1 the conversion concepts were built and tested on a single-cylinder engine. In phase 2 one of these was put into effect in a 6-cyl (DDA 6V-71) engine. The design concept with the most promise includes a divided combustion chamber utilizing a gas inlet valve in each chamber and a spark plug ignition source located in the prechamber. The concept has the potential of reducing the exhaust emissions well below the levels now existing in commercial diesels without exhaust smoke and odor and with equivalent fuel consumption and horsepower, as demonstrated in the single-cylinder conversion. Further development work remains to be done to perfect the concept for the multi-cylinder engine.

The theory of submerged jets is applied quantitatively and qualitatively to diesel fuel sprays, based on simple considerations of the inherent invalidity of the single-particle “ballistic” approach. Approximate theoretical results are obtained for penetration velocity, penetration versus time, and fuel-air ratio within the spray. Modeling experiments are discussed and the jet approach used to explain two types of diesel combustion situations-fuel entrapment by insufficient penetration in the presence of air swirl and the efficacy of the MAN process.

The major events in the development of a “pumpless” gas engine concept are related. The immediate objective of the subject program was to develop a combustion system for natural gas fueled engines which, when compared with conventional gas engines, would be operationally simpler and easier to maintain with no appreciable penalty in specific fuel consumption. The pumpless gas principle was successfully demonstrated on a single-cylinder, 2-cycle engine. The concept was then extended, with the aid of combustion photography, to a single-cylinder, 4-cycle laboratory engine. The feasibility of the concept was further demonstrated by the conversion of a commercially available 4-cycle, 4-cyl diesel engine.

Exhaust heat utilization for internal combustion engines has centered around turbosupercharging in recent years, neglecting the promising field of compounding a piston engine with a gas turbine in which, unlike turbocharging, turbine power is fed back to the engine crankshaft. The piston engine can cope with high gas pressure and temperature, whereas the gas turbine can efficiently utilize the energy at relatively low pressure and temperature and large volume flows. By compounding, this-piston engine will handle the high pressure, high temperature phase of the combustion cycle and extend the expansion ratio of the gases to atmospheric pressure by completing the low pressure, low temperature phase in the gas turbine. The marriage of the two engines will result in an outstanding power package with the highest thermal efficiency possible.