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In an effort to improve the trade-off between fuel economy and emissions in the rotary combustion engine, research was undertaken to provide a better understanding of the sources of unburned hydrocarbons in the exhaust. Flame photography was used in conjunction with extensive time-resolved exhaust gas sampling. Examinations were made of the effects of air-fuel ratio, engine load, residual gas, and engine speed on combustion and hydrocarbon emissions using the two experimental techniques. These studies identified two major sources of hydrocarbon emissions: flame extinction and, not surprisingly, apex seal leakage. Conclusions were the following: (1) at lean air-fuel ratios (i.e., ≥18.0 to 1), flame extinction in the trailing portion of the chamber was a major source of exhaust hydrocarbons, and (2) at richer air-fuel ratios (i.e., ≤16.5 to 1), apex seal leakage was a major source of exhaust hydrocarbons.

Legislated fuel economy standards have necessitated investigations to determine the cost-effectiveness of “low-friction” engine lubricants to assist in attaining these goals. Preliminary testing indicated friction reduction engine oil additives may provide potentially significant improvements in fuel economy over conventional and low viscosity engine oils. Vehicle test programs were undertaken to evaluate the effects of molybdenum disulfide, graphite and soluble additives on fuel economy, engine cleanliness and wear, as well as exhaust emission levels and engine and emission component durability. The significant fuel economy improvements and effects on all aforementioned variables are detailed in the paper.

Today's commercial transport service vehicle owner is being confronted with increasingly complex problems in his vehicle operation. As a means of solving one of his problems, methods of evaluating power train components and their effect on obtaining optimum vehicle performance and efficiency have been developed. Vehicle vocation variables and the different types of power trains and power components have been analyzed. Utilization of the techniques described should bring the vehicle engineer closer to providing an optimum match of vehicle, engine, transmission, axle, and tires for a given vocation.

Results from a numerical investigation of one-dimensional, laminar flame quenching with constant and time-dependent pressure variations are reported herein. A description of flame quenching and post-flame oxidation processes for the global reaction A + B → C is obtained from a solution of a simplified form of the non-linear conservation of mass, momentum and energy equations in a planar flow field. These equations were reduced to finite difference form and the time-dependent pressure was input via either an integrated form of the energy equation or a third-order polynomial law. Numerical calculations were performed at constant pressure, combustion bombtype conditions and under rapid decompression during quenching. One-dimensional head-on quenching distances, hydrocarbon concentration levels and gas properties were obtained for a variety of stoichiometric values in a propane/airtype mixture.

The effect of bore-to-stroke ratio (B/S) on indicated specific fuel consumption (ISFC) and emissions of a gasoline-fueled, spark-ignited, single-cylinder engine was studied while holding compression ratio and bore diameter constant. As B/S was increased from 1.1 to 3.3, both ISFC and hydrocarbon emissions increased significantly. Increased cylinder heat loss and, to a lesser extent, increased combustion duration were the principal causes of the ISFC increase. Increased surface-to-volume ratio was the principal cause of the increase in hydrocarbon emissions. The influence of combustion chamber modifications on these effects was investigated.

Measurements of engine cylinder pressure have become routine at the General Motors Research Laboratories. EDPAC, an Engine Diagnostic Package, was designed and developed to process these data automatically from single-and multi-cylinder engines in order to provide engine performance and combustion information. EDPAC consists of several self-contained, independent software modules, each having a different analysis function. These include engine performance calculations, pressure-volume graphics, engine simulation for residual gas estimates, and heat release analysis. After each module is executed, computed results are stored automatically, providing input to subsequent software modules as well as providing a data base for future interrogation. Routine use of EDPAC to process pressure data results in reductions of costs, effort, and turn-around times. A data base containing performance, emissions, and combustion data is established automatically.

This paper describes the results of experimental and computer simulation studies of the combustion process in the prechamber three-valve stratified-charge engine. Prechamber and main-chamber pressure data and matched computer simulation calculations are used to determine the effects of variations in overall air/fuel ratio, engine speed and load, and prechamber volume and orifice diameter on the parameters which define the combustion process (spark advance for optimum torque, ignition delay, combustion duration), on cylinder pressure diagrams (mean main-chamber pressure, mean pressure difference across the orifice, and cycle-by-cycle pressure fluctuations) and on exhaust emissions. General correlations are derived from the data for the shape of the combustion rate profile and the extent of the combustion duration.

A method for monitoring the wear of engine parts without engine disassembly is described. Low level radiation sources implanted in the wearing surfaces serve as a tracer for material loss. Prior to engine testing, controlled wearing of an identical part determines a calibration curve relating wear depth to externally measurable radiation. The results of engine testing show that the method is useful in measuring small amounts of wear in individual engine parts such as piston rings and connecting rod bearings simultaneously without engine disassembly. These tests were performed to evaluate the effectiveness of filters in reducing engine wear. The wear measurements showed that both air and oil filters are highly effective in reducing wear throughout an engine.

Today's diesel engine lubricating oils are highly dispersant and typically carry several pounds of solid combustion contaminant in suspension - little of which is filterable. Since the average full flow filter is capable of holding less than a pound of solids, filter life and capacity are no longer directly related. Field experience has demonstrated at least six distinct methods by which filters plug. This data indicates that filter life is simply a function of the type and amount of contaminant present in the crankcase and the oil's ability to handle or tolerate the contamination. However, oils differ greatly in their ability to do this. Field experience also suggests that the current API Classification tests may be inadequate in some areas to determine lubricating oils' suitability for diesel engine service. Finally, filter plugging should be looked at as a symptom of engine or oil problems, but not as a problem itself.

Experimental Brake Specific Fuel Consumption (BSFC) data are presented for two engines as a function of engine speed, load, outlet coolant temperature and inlet oil temperature. The engines used in the study were the Cummins VT-903 (turbocharged) and the Caterpillar 3208, both being direct-injection and four-cycle. The data were taken for the Cat 3208 engine using a fractional factorial statistical method which reduced the total test matrix from 256 to 64 data points. The experimental data are used in the development of BSFC regression equations as a function of load, speed, outlet coolant temperature and inlet oil temperatures. A mathematical parameter for expressing quantitatively the change of BSFC per 10°F change in coolant and oil temperature is presented. It was found that an increase in the coolant and/or oil temperatures had the effect of reducing BSFC in both engines.

This investigation dealt with the experimental determination of a select chemical specie - the hydroxyl radical - present in the non-flamed end gases ahead of the flame front in a spark-ignited engine operating under conditions of both normal and knocking combustion. Concentration measurements of the hydroxyl radical present in the end gases were obtained with the technique of resonance absorption spectroscopy utilizing a broadband-output, frequency-tunable, flashlamp-pumped, organic-dye laser. The dye laser and a photographic spectrometer were placed on opposite sides of a single cylinder research engine and the combustion chamber of the engine was fitted with quartz windows that allowed the dye-laser light pulse to pass through the end gas region and into the spectrometer. The dye laser was pulsed once at a present crankangle during the combustion cycle recording the 2∑+-2∏ electronic transition absorption spectrum on film.

The State-Of-The-Art of automotive corrosion testing is reviewed with particular emphasis on testing related to the exterior environment. The generally poor correlation of laboratory tests with field performance is reviewed and the factors affecting both laboratory and field tests are discussed. Recommendations for the conduct of field tests are presented.

A brief review of the basic theory of the electrochemical corrosion of metals is presented, with emphasis given to the mixed-potential theory. Currently accepted electrochemical corrosion mechanisms of several major forms of corrosion are reviewed. Galvanic, crevice and pitting types of corrosion are considered. The presently held theories on the atmospheric corrosion of steel is also discussed.

Typical automotive finishing practices are described with emphasis on paint system capabilities and limitations that affect painted part corrosion resistance. Limitations of each finishing step are reviewed along with suggestions for suitable part design to overcome system deficiencies.

Ontario upholds a high level of maintenance service on its highways during the winter months. The majority of these roads are maintained to bare pavement condition, while others are maintained to center bare condition. This paper describes the methods used to obtain this level of service under various winter conditions. Recently, environmentalists have expressed their concern over the effects of salt used for winter maintenance on the environment. In response to this concern, Ontario has begun a research program to evaluate the effect of salt on the environment, and to find techniques for reducing the amount of salt used, while still providing the current level of service to the public.

An overview of the principal factors involved in the initiation and propagation of the corrosion of painted steel is presented. One of the major protective functions of the paint system is to act as a barrier to electrolyte; corrosion begins at sites where penetration of electrolyte has occurred. Loss of paint adhesion, caused in most cases by cathodically produced alkali, results in the spread of corrosion. Improved corrosion protection can be obtained by use of alkali-resistant paint binder resins. Corrosion inhibitive pigments can improve performance by slowing the overall corrosion rate; conversion coatings can slow the lateral spread of alkali attack.

The interaction of our natural elements such as rain, snow and humidity, with chemicals introduced to the environment, provides a complex chemistry which is one of the most corrosive in North America. The chemistry of this environment and its relevancy to automotive corrosion, forms the basis of this paper. An understanding of this chemistry is necessary in order to conduct meaningful corrosion tests and reduce degradation of automobiles.

This paper presents the state of the art on the selection and use of de-icing chemicals and abrasives. More specifically, it deals with: the need for de-icing chemicals and abrasives, problems associated with them, alternative solutions, factors to consider when selecting the appropriate solution, the current practice, and the future trends in the use of chemicals. Based on a recent literature survey, the author concludes, that, even though we are on the verge of a breakthrough, until the time comes, we should be prepared to live with these chemicals for many years, and that the adverse effects due to chemical use can be minimized through the combined efforts of road and automotive engineers, especially through the application of existing knowledge.

Computer-aided crash reconstruction has become common-place in the automotive safety profession, primarily because of widespread distribution of software under public auspices. The SMAC (Simulation Model of Automobile Collisions) program, for instance, is available through NHTSA at nominal cost. This paper exhibits some of the limitations and strengths of accident reconstruction simulations, with illustrations and emphasis drawn from the SMAC program. In particular, some coarse physical approximations used and some coding errors incurred in the formulation of SMAC are discussed, together with their respective effects on the accuracy of prediction. Revisions of the basic SMAC coding have been developed at BYU to overcome these shortcomings. Results of uncorrected and revised SMAC simulations are demonstrated by comparison with the physical theory. Comments regarding a new SMAC program just completed under U.S. Government contract are presented where appropriate.