https://biblio.ugent.be/publication/818298/file/818329.pdf

Hydrogen-fueled internal combustion engines

Four types of hydrogen detectors are used by researchers, engineers, and manufacturers 
today, and if hydrogen continues to play a role in emerging alternative energy sources, 
there will be exponential growth in the use and need for more advanced and more robust 
devices in the future. The types of sensors reviewed in this chapter are (1) room-temperature hydrogen leak sensors; (2) thermometers, particularly useful at low temperature; 
(3) liquid hydrogen volume and mass gauges; and (4) para/ortho hydrogen ratiometers.

Since the use of diesel engines is still increasing, the contribution of their incomplete combustion products to air pollution is becoming ever more important. The presence of irritating and genotoxic substances in both the gas phase and the particulate phase constituents is considered to have significant health implications. The quantity of soot particles and the particle-associated organics emitted from the tail pipe of a diesel-powered vehicle depend primarily on the engine type and combustion conditions but also on fuel properties. The quantity of soot particles in the emissions is determined by the balance between the rate of formation and subsequent oxidation. Organics are adsorbed onto carbon cores in the cylinder, in the exhaust system, in the atmosphere and even on the filter during sample collection. Diesel fuel contains polycyclic aromatic hydrocarbons (PAHs) and some alkyl derivatives. Both groups of compounds may survive the combustion process. PAHs are formed by the combustion of crankcase oil or may be resuspended from engine and/or exhaust deposits. The conversion of parent PAHs to oxygenated and nitrated PAHs in the combustion chamber or in the exhaust system is related to the vast amount of excess combustion air that is supplied to the engine and the high combustion temperature. Whether the occurrence of these derivatives is characteristic for the composition of diesel engine exhaust remains to be ascertained. After the emission of the particles, their properties may change because of atmospheric processes such as aging and resuspension. The particle-associated organics may also be subject to (photo)chemical conversions or the components may change during sampling and analysis. Measurement of emissions of incomplete combustion products as determined on a chassis dynamometer provides knowledge of the chemical composition of the particle-associated organics. This knowledge is useful as a basis for a toxicological evaluation of the health hazards of diesel engine emissions.

Combustion of diesel fuel from a toxicological perspective. I. Origin of incomplete combustion products.

A Critical Review of Experimental Research on Hydrogen Fueled SI Engines

Tests were conducted in a Cooperative Fuel Research (CFR) diesel engine aimed at discerning the effects of fuel aromatic and oxygenate compounds on exhaust emissions. The base fuel was heptane to which were added increasing amounts of monoaromatic toluene and diaromatic methylnaphthalene. Blends of heptane and toluene containing oxygenated compounds (methanol, ethanol, heptanol and diglyme) were also tested. The results indicate that both toluene and methylnaphthalene increase smoke, oxides of nitrogen (NOx) and unburned hydrocarbon (UHC) emissions substantially. The results also showed that increases in ignition delay could account for some of these rises in exhaust emissions. The oxygenated fuel blends tested caused reductions in NO and smoke emissions. The exception was heptanol, which showed no reduction in smoke emission. This may be associated with the fact that heptanol had the lowest amount of molecular-bound oxygen. © IMcchE 2000.

The effect of aromatic hydrocarbons and oxygenates on diesel engine emissions

Due to the cost and mobility advantages of diesel-powered mine vehicles over electric vehicles, it is anticipated that the diesel engine will become more widely used in underground mines in this country. Concern has arisen, however, over the impact of diesel exhaust emissions on the air quality in the underground mine environment. A literature search has been conducted, however, the data base is relatively small and the results highly dependent on engine type and operating conditions. Engine studies on a typical mine diesel are necessary to draw quantitative conclusions regarding the reduction of emissions, especially particulates and NO/sub 2/ which have not been generally addressed in previous studies. 52 refs.

The Effects of Fuel Properties and Composition on Diesel Engine Exhaust Emissions - A Review

The Bureau of Mines' Hydrogen Powered Mine Vehicle

The effects of fuel properties and composition on emissions of particulate matter, oxides of nitrogen, unburned hydrocarbons, and carbon monoxide were investigated in this study. Fuels and fuel blends evaluated included DF-1, DF-2, and JP-7; a solution and an emulsion of ethanol with DF-2; emulsions and fumigation of water with DF-2; and LPG with DF-2 pilot injection. All tests were performed on a diesel engine (Caterpillar 3304) representative of underground mining equipment. 2 refs.

Control of Diesel Exhaust Emissions in Underground Coal Mines-Single Cylinder Engine Experiments with Modified and Non-Conventional Fuels

The responses of diesel engine exhaust emissions to transients in speed and torque are examined. Particulate matter, hydrocarbons, carbon monoxide, and oxides of nitrogen were sampled for discrete segments of various transient cycles. Each cycle consisted of four distinct segments, two of which were steady state. In general, each segment was defined by choosing the beginning and ending values for speed and torque, and the segment length. Using regression techniques, prediction equations were obtained for each emission. The equations relate the emission levels to engine parameters, which describe each segment. Speed and torque were found to be important variables as were the rates at which speed and torque changed. Transients in torque were found to increase particulate and carbon monoxide emissions. Emission trends for transient speed segments were similar for particulate, carbon monoxide, and nitrogen oxide emissions; i.e., emission levels decreased for decelerations and increased for accelerations.

The effects of discrete transients in speed and load on diesel engine exhaust emissions

This paper is the fourth in a series describing work sponsored by the Bureau of Mines to reduce diesel particulate and gaseous emissions through fuel modification. A stabilized water microemulsion fuel developed in previous work was tested in a Caterpillar 3304 NA four-cylinder engine with compression ratio and injection timing and rate optimized for this fuel to demonstrate the emissions reductions achieved. It was tested in both standard and optimum configurations with both baseline DF-2 and optimized microemulsion fuels. Gaseous and particulate data are presented from steady-state tests using a computer-operated minidilution tunnel and from transient tests using a total exhaust dilution tunnel. The optimized engine-fuel combination was effective in reducing particulates and oxides of nitrogen in steady-state tests. However, the standard engine-fuel combination provided the lowest particulate and NOX emissions in transient tests.

Control of Diesel Exhaust Emissions in Underground Coal Mines - Steady-State and Transient Engine Tests with a Five Percent Water-in-Fuel Microemulsion

Robert W. Waytulonis

Papers

The Effects of Fuel Properties and Composition on Diesel Engine Exhaust Emissions - A Review

The Bureau of Mines' Hydrogen Powered Mine Vehicle

Control of Diesel Exhaust Emissions in Underground Coal Mines-Single Cylinder Engine Experiments with Modified and Non-Conventional Fuels

The effects of discrete transients in speed and load on diesel engine exhaust emissions

Control of Diesel Exhaust Emissions in Underground Coal Mines - Steady-State and Transient Engine Tests with a Five Percent Water-in-Fuel Microemulsion