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A technique for making a radiometric measurement of the deposit surface temperature in a methane-fired engine was developed. The wavelength region between 3.5 and 4.1 μm was investigated. It was determined that while the combustion gases were relatively transparent, the surface temperature measurements would contain some gas radiation. A method of averaging the measurements of many cycles and correcting these data for the gas radiation was developed. Time-averaged surface temperature was used in a steady-state heat transfer analysis to determine deposit thermal conductivity. Deposit thermal diffusivity was determined from a transient experiment in which the engine’s ignition system was turned off and the cooling response of the deposit and wall were measured.

A technique to determine time and space resolved particulate number density and size in the cylinder of an operating diesel engine is described and sample data presented. Basically the technique uses Mie scattering of a laser beam passed through the jet of gases leaking through a 0.015 diameter orifice inserted into the combustion chamber. Number density and size are inferred from measurements of scattering as a function of angle of scattering. The data show a linear relationship between exhaust measurements using this technique and Bosch smoke meter readings as well as an approximately linear relationship between in-cylinder measurements of number density and mass measurements made by collecting particulates flowing through the 0.015 in, orifice on a filter.

An intermittent sampling valve was used to investigate local fuel H/C ratio and species concentrations in an operating DI diesel engine. Additionally, predictions of carbon and hydrogen originating from particulates and nonmethane hydrocarbons (carbon and hydrogen remainders) were made by calculation. Sample H/C ratio was used to assess local fuel phase as gaseous or liquid. Evidence of intermediate species quenching in the lean region between spray plumes was found under low swirl. Reduction in the rate of penetration under high swirl may account for the observed loss in efficiency under this condition.

IT IS WELL RECOGNIZED that the idling and part load fuel economy of diesel engines are better than throttled controlled spark ignition gasoline engines. Using well known principles the explanations for the difference are presented. Fuel consumption rate for similar engines and mileage for similar weight vehicles are presented in graphical form. Trends of demand, supply and reserve of crude oil for the World and the United States are shown in graphical form. Future supply scenario of crude oil is presented. The cost of making synthetic crude from coal is very roughly predicted.

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.

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.

Problem areas in engine simulation where the required information is lacking are discussed. The need for improved heat transfer, combustion, friction, and turbocharger models is discussed as are instrumentation needs for measurements of accurate pressure, radiant heat transfer, time-varying cylinder velocities, and instantaneous mass flow rates.

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.

By the use of surface thermocouples to measure instantaneous temperatures, the instantaneous heat fluxes are calculated at several positions on the cylinder head and sleeve of a direct injection diesel engine for both motored and fired operation. Existing correlations are shown to be unable to predict these data. An analysis of convective heat transfer in the engine leads to a boundary layer model which adequately correlates the data for motored operation. The extension of this motored correlation to fired operation demonstrates the need for instantaneous local gas velocity and temperature data.

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.

The development of a high speed, multichannel data acquisition system is described. A precision magnetic tape recorder is used to record analog data from highly transient phenomena. Analog-to-digital data conversion is performed on a hybrid computer and the digitized data is processed using large, high speed digital computers. A detailed example of the application of the system to the measurement of rates-of-injection, rates-of-heat release, and instantaneous rates-of-heat transfer from the cylinder gases to the cylinder walls in a high speed open-chamber diesel engine is presented.

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.

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.

Fine-wire resistance thermometers were used to measure compression gas temperatures in a motoring (nonfiring) cycle CFR engine. Temperature versus crankangle curves were obtained for the compression and expansion strokes by means of tungsten wires ranging in diameter from 0.15–1.00 mils and at speeds from 600–1800 rpm. The results were compared with the infrared pyrometer; the peak temperature and peak crankangle lags were determined as a function of the wire diameter and engine speed. Attempts to evaluate the instantaneous energy balance around the wire resulted in a negative heat transfer coefficient, for which no current satisfactory explanation is available, although other observers have reported similar phenomena. The tungsten resistance thermometer is simple to build, easy to install, and requires no modification of the engine block for use during motoring. Thus, it is suitable for comparing the compression temperatures of different design engines.

The ratio of two temperature gradients across the combustion-chamber wall in a diesel engine is used to provide a heat flow ratio showing the radiant heat transfer as a per cent of local total heat transfer. The temperature gradients were obtained with a thermocouple junction on each side of the combustion-chamber wall. The first temperature gradient was obtained by covering the thermocouple at the cylinder gas-wall interface with a thin sapphire window, while the second was obtained without the window. Results show that the time-average radiant heat transfer is of significant magnitude in a diesel engine, and is probably even more significant in heat transfer during combustion and expansion.

Life histories of droplets evaporating on a hot plate under pressure were obtained. The curves are similar to those obtained by one investigator at atmospheric pressure but are displaced to higher temperatures at higher pressures. Similarities between boiling heat transfer and the life history curves are pointed out. Also, that the liquid will most probably reach critical pressure and temperature at temperatures existing inside an engine. The effects of reaching the critical temperature on heat transfer and on vaporization and diffusion are discussed.

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.