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Ethylene, propylene, n-butane, and 1-butene, which make up a large portion of the photochemically reactive hydrocarbons in automobile exhaust, were reacted individually and as a mixture in a turbulent flow, heated reaction tube made of mild steel. Methods of predicting the total hydrocarbon disappearance by use of a general empirical equation are presented. Techniques for using hydrocarbon composition and carbon monoxide data to predict exhaust photochemical reactivity and CO concentration from total hydrocarbon disappearance correlations are suggested. Results show that total hydrocarbon reaction was generally strongly dependent on temperature and on oxygen concentration between 1% and 5%, and was less dependent on initial hydrocarbon concentration. Gas Chromatograph data showed that during certain individual hydrocarbon reactions, the formation of other photochemically reactive hydrocarbons could increase smog-forming potential despite a decreasing total hydrocarbon concentration.

Effects of engine parameters on performance can be investigated by using a mathematical model of the engine cycle, and the computed results may be used to optimize performance. The following design parameters were varied: crankcase clearance volume, exhaust and transfer port timings, exhaust and transfer port areas and bore/stroke ratio. Studies assumed both constant and variable exhaust pressures.

FLAME-temperature data obtained with the electro-optical pyrometer developed by the University of Wisconsin are presented for diesel fuels of selected composition, together with reproducibility data for the test engine and equipment. Although insufficient data are available for a valid correlation of combustion performance with fuel characteristics, a few correlation procedures are suggested.

An instrument was developed to measure absolute monochromatic infrared emission rates within an operating diesel engine. The instrument and data reduction system were developed for use in obtaining potential instantaneous rates of radiant heat transfer within an operating engine. Data are presented for variations of: engine speed, fuel-air ratio, fuel injection timing, intake air pressure, fuel injector nozzle spray patterns, fuel cetane numbers, fuel family, and fuel additives (tetraeythl lead and amyl nitrate). Also presented is an empirical correlation for instantaneous radiant heat transfer rates and some conclusions regarding radiant emission sources within the engine and their relationships to combustion processes.

Instantaneous heat transfer rates at the interface of the working gas and the walls of a motored engine were studied. This paper details the influence on heat fluxes of engine speed, compression ratio, intake pressure, swirl ratio, location on the cylinder head surface, and the shape of the piston top. Equations are given to show the method of calculation used in deriving the data on heat transfer rates.

A NEW electronic circuit arrangement added to the electro-optical pyrometer developed at the University of Wisconsin indicates instantaneously the temperature in the combustion chamber of a diesel engine. The electronic device, which is described in this paper, solves an equation relating true temperature to intensity and wave length of monochromatic radiation from a luminous flame. True flame temperature is charted on an oscillograph as a function of such abscissas as time or crank angle. Several circuits are reviewed which were found unsuited for use with the pyrometer but which may be useful for other applications.

This paper describes a new application of Karman vortex shedding frequency as a velocity sensor in a motored internal combustion engine cylinder. The probe design, experimental setup and data reduction procedures are described. The quality of data obtained depends strongly on the relative frequency distribution of the free-stream turbulence and of the vortex shedding induced by the vortex generator. The instrument was evaluated on a CFR engine equipped with a shrouded intake valve. The results are presented in terms of the airswirl ratio at several selected crank angle degrees versus engine speed. The limitations of the device were also demonstrated in L-head engine tests.

Various homogeneous charge and stratified charge engine configurations were studied at wide-open throttle conditions, using simplified computer models. An order-of-magnitude parametric study was performed to find those combinations of variables which predicted a low nitric oxide level. Extreme values of variables were studied for a homogeneous charge engine configuration, which could be difficult to do in a real engine. As expected, these calculations indicated that for practical engine operation the equivalence ratio of the mixture must either be very rich or very lean for a resultant low nitric oxide level. Two extremes of stratified charge engine operation were investigated analytically, in other words, immediate mixing of newly formed products of rich combustion with excess air (instantaneous mixing) and a period of rich combustion followed by air addition to the rich products (delayed mixing). Comparisons of power, efficiency, and specific NOx are presented.

Obtaining and maintaining a stratified charge in a practical engine is a difficult problem. Consequently, many approaches have been proposed and reported in the scientific and patent literature. In attempting to assess the most profitable approach for future development work, it is important to group together similar approaches so that one can study their performance as a group. Making such a classification has the additional advantage of helping to standardize terminology used by different investigators. With this thought in mind, a literature study was made and a proposed classification chart prepared for the different engine combustion systems reported in the literature. For the sake of completeness, the finally proposed classification chart includes homogeneous combustion engines as well as heterogeneous combustion engines. Because of their similarity of combustion, rotary engines such as the Wankel engine are considered as “reciprocating” although gas turbines are not included.

Gas concentrations, under different engine operating conditions, different locations relative to the fuel spray are presented. The gas that is sampled is “snatched” from a continuous flow sampling probe. The time of snatching is controlled. The concentrations of CO, CO2, NOx, and O2 are plotted against, crank position. The sampled gases were analyzed for concentration in the as taken state and after the sampled gas had passed through a heated catalytic oxidation converter. Analysis have been performed and plots are presented of the findings. The analytic procedure developed for the data analysis are presented in detail.

An investigation into effects of multiple fuel introduction on isfc, rate-of-pressure rise, ignition delay, and smoothness of P-T diagram was conducted. Work, including pilot and manifold injection and the Vigom process, was conducted in a prechamber, an open chamber, and a Ricardo Comet chamber, all mounted on a CFR crankcase. Results show marked smoothening of the P-T diagram, with slight loss in fuel economy, particularly in the open chamber, and decrease in ignition delay for both high and low cetane fuels, especially at lower engine speeds. Data show that the quantity of preliminary fuel required for best performance changes considerably with cetane number of the fuel and with combustion chamber.

An evaluation of the many new devices proposed, in recent years, for power production. Among these are fuel cells, thermoelectric generators, thermionic generators, and solar cells. Comparisons of these energy converting devices are based on ultimate efficiency (thermodynamic principles), weight, size, and cost, when possible.

The purpose of the tests conducted on a single-cylinder laboratory engine was to determine the mechanism of combustion that affect exhaust emissions and the relationship of those mechanisms to engine design and operating variables. For the engine used in this study, the exhaust emissions were found to have the following dependence on various engine variables. Hydrocarbon emission was reduced by lean operation, increased manifold pressure, retarded spark, increased exhaust temperature, increased coolant temperature, increased exhaust back pressure, and decreased compression ratio. Carbon monoxide emission was affected by air-fuel ratio and premixing the charge. Oxides of nitrogen (NO + NO2 is called NOx) emission is primarily a function of the O2 available and the peak temperature attained during the cycle. Decreased manifold pressure and retarded spark decrease NOx emission. Hydrocarbons were found to react to some extent in the exhaust port and exhaust system.

Digital computer methods were used to investigate the behavior of engine operating characteristics with a time-varying gas-film heat-transfer coefficient and gradual buildup of combustion-chamber deposits. Simulated engine runs were made with a “clean” engine having different wall materials and operating at different engine speeds as a basis for comparison. From the data calculated, heat transfer rates were established and inferences drawn regarding trends of detonation, preignition, and volumetric efficiency during the deposit buildup period. It was found that, while thermal resistance (x/k)d of the deposit layer is the most important parameter, a secondary parameter of interest is the thermal penetration, , in comparing the effects of deposits of different properties.

The first part of the paper deals with the mathematical model and computer program for simulating a compression-ignition engine. The various assumptions used and the effects of these assumptions on the results are discussed. The second part of the paper evaluates results of the engine simulation program by comparisons with experimental data and with other simplified cycle calculations. The comparisons with experimental data include motoring, part load, and full load data for a speed range of 1400–3200 rpm. The simulation results show good agreement with experimental pressure-volume diagrams. The computed trends of volumetric efficiency, heat rejection, and metal part temperatures show reasonable agreement with experimental data.

This paper describes a method for studying reactions of hydrocarbons in S.I. engine exhaust gases. The reaction of ethane is described using an Arrhenius model (experimentally E = 86,500 cal/mole) for the rate of ethane diappearance and empirical correlations for distributions of the products carbon monoxide, ethylene, formaldehyde, methane, acetylene, and propane as a function of the fraction of ethane reacted. The results show that the nature of partial oxidation products from a nonreactive hydrocarbon may be less desirable from an air pollution viewpoint than the initial hydrocarbon.

The reasons for conducting research in a university are presented and discussed. It is concluded that fuel-engine studies are compatible with these reasons and therefore are well suited for university research. Past studies in this field are summarized and unanswered questions and future topics suitable for university investigation are suggested. Included in the topics discussed are: instrumentation, thermodynamic description of working fluids, fuel vaporization and atomization, combustion, and instantaneous heat transfer and mass flow rates. The steps that need to be taken to ensure continuing university interest in fuel-engine studies are presented.

To determine the effects of knock in a spark-ignition, single-cylinder engine with cooled exhaust upon the exhaust composition, exhaust products (CO, CO2, and total hydrocarbons) were measured by non-dispersive infrared analyzers (NDIRA) and by a flame ionization detector (FID). Individual hydrocarbons were separated on a gas-liquid chromatograph. In fuel-rich mixtures, the FID indicated noticible decreases in the hydrocarbon concentrations in the presence of knock. The NDIRA did not indicate a decrease in the hydrocarbons at knock of lower intensities but showed decreases in hydrocarbons at knock of higher intensities. Chromatograms indicated a preferential decreases in acetylene at the time of knock, causing different responses at lower intensities. In fuel-lean mixtures, no apparent effect of knock on the hydrocarbons was indicated.

A detailed mathematical model of the thermodynamic events of a crankcase scavenged, two-stroke, SI engine is described. The engine is divided into three thermodynamic systems: the cylinder gases, the crankcase gases, and the inlet system gases. Energy balances, mass continuity equations, the ideal gas law, and thermodynamic property relationships are combined to give a set of coupled ordinary differential equations which describe the thermodynamic states encountered by the systems of the engine during one cycle of operation. A computer program is used to integrate the equations, starting with estimated initial thermodynamic conditions and estimated metal surface temperatures. The program iterates the cycle, adjusting the initial estimates, until the final conditions agree with the beginning conditions, that is, until a cycle results.