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A mathematical model has been developed to analyze fluid flow in carburetors of single-cylinder engines. Single and multi-phase flow are modeled for steady-state-cyclic and transient conditions. This provides insight to design parameter interactions not adequately analyzed with steady-state techniques. The model predicts pressures and flow rates by utilizing an implicit finite-difference solution of one-dimensional equations of conservation of mass and momentum. Example applications and experimental verification are provided.

Technical and idealogical conflicts exist in the world of motorcycling, particularly concerning motorcycle dynamics. Current output from minimal scientific research in motorcycle handling and response provides direct contradiction of some erroneous motorcyclist theories but fails to provide definition of optimum motorcycle chassis design parameters.

A test methodology has been developed for objectifying the measurement of motorcycle braking performance through use of a towing technique. The rationale behind the procedure is presented, together with an analysis of the mechanics of braking performance during the towing of a motorcycle. The tow-test method includes the full complement of performance evaluations, viz., effectiveness, burnish, thermally-induced fade, and wetted brake performance. This set of tests was performed on two motorcycles and the resulting data are presented and discussed.

A systematic plan is being implemented which holds promise for reducing motorcycle accidents and injuries through motorcycle operator education and licensing improvement. Through a unique public-private sector partnership, motorcycle task analysis research has been completed, and an evaluation of the effectiveness of improved operator licensing examination is on-going. Near-future efforts will test the effectiveness of a motorcycle rider (operator) education course. Improved motorcycle dynamics and operator handling can be anticipated upon completion of this research and development effort. Successful implementation promises a reduced likelihood of accident involvement during the initial months of motorcycle operation.

The results of full-scale tests in lane change maneuvering as performed by four riders of varying experience with the same motorcycle are analyzed. Measurements of rider input (steer angle, steering torque, and lean angle) and of vehicle response (roll angle and yaw rate at constant speed) are used to compare riding techniques. The effects of skill and experience are examined by means of graphical representations of rider operations. Test course geometry, instrumentation methods, motorcycle characteristics, and rider backgrounds are described. It is shown that the experienced rider performs more smoothly and efficiently and achieves a higher limit than those with less experience.

Preliminary results of a study to develop lateral-directional handling test procedures for motorcycles are presented. One is a steady-state turn, accomplished with a range of forward speeds and turn radii. The other is a single lane change maneuver, using various degrees of severity and forward speeds. Several example motorcycles were studied analytically and via full scale tests. Data from onboard instrumentation show the effects of vehicle and operational differences on selected response and performance measures. This paper comprises a progress report, and the work is continuing.

In order to prevent aquaplaning and skidding pavements can be grooved or roughened. However, it is not exactly known whether such treatments might negatively influence riding behavior of motorcyclists. In this study riding a motorcycle on roughened and grooved pavements was compared with riding on normal asphalt and cobbles. Overall results of objective and subjective data seem to justify the following conclusions: (1) grooved and roughened pavements indeed may influence riding behavior of motorcyclists negatively and (2) in the case of grooves, differences in groove dimensions lead to different effects: small grooves with small interspaces hardly showed an effect.

A method is described of calculating the flow, temperature and turbulence fields in cylinder configurations typical of a direct-injection diesel engine. The method operates by solving numerically the Navier Stokes equations that govern the flow, together with additional equations representing the effects of turbulence. A general curvilinear-orthogonal grid that translates with the piston motion is used for the calculations in the complex-shaped piston bowl, whilst an expanding/contracting grid is used elsewhere. Predictions are presented showing the evolution of the velocity and turbulence fields during the compression and expansion phases of a motored engine cycle, for various shapes of axisymmetric piston bowl and various initial swirl levels. These results illustrate the strong influence of these factors on the TDC flow structure.

The U.S. Postal Service and the Department of Energy have jointly developed and installed a flywheel system in a 1/4 ton electric postal delivery vehicle. The completed vehicle is undergoing test and evaluation. Electric vehicles have the advantage over existing internal combustion engine vehicles of producing minimum pollution and requiring no oil based fuels. Preliminary test results show that adding a flywheel can significantly improve performance and increase the potential application of the electric vehicle for postal delivery service without an increase in energy consumption.

Material, processing, and development experience with vacuum brazing of aluminum radiators is reviewed. The welded, clad tube and bare fin concept is shown to be economically and technically superior to other designs. The mechanisms of vacuum brazing and process requirements are reviewed as they apply to radiators. Individual components and joint areas are examined to illustrate solutions to specific problems.

A non-corrosive flux for brazing aluminum has been developed. Use of the flux for furnace brazing is described. The characteristics of heat exchangers brazed by the process are presented. The results show considerable promise for economical and reliable use of the process in brazing automotive heat exchangers.

Vacuum brazing technology is currently capable of producing aluminum automotive heat exchangers such as radiators and heater cores. The possible use of 7072 claddings on the surfaces exposed to the coolant to provide additional corrosion protection is of considerable interest. This paper describes the effect of typical vacuum brazing cycles on the distribution of zinc in 7072 clad vacuum brazing sheet. For heavier gauges (.05″), there is sufficient retained zinc in the post-braze composite. For lighter gauges (.02″ or less), nominal composition 7072 does not provide adequate retained zinc; however, if the initial zinc concentration is increased to 3% there is sufficient retained zinc so that the cladding is significantly more anodic than the core.

Before aluminum can be used in automotive radiators and heater cores, assurances are required that corrosion performance will be satisfactory. Accelerated laboratory glassware tests, however, indicate that conventional aluminum brazing sheet materials may not be suitable under service conditions unless significant improvements are made in corrosion resistance and/or coolant inhibition. Although corrosion performance can be greatly improved by utilizing an inner anodic cladding alloy (Alclad concept), fabricating and manufacturing processes would be simplified by using a conventional product in a properly inhibited cooling system.

A theoretical and empirical view is taken of motorcycle lateral-directional dynamics, handling, and rider control behavior. The analytical development includes equations of motion for the vehicle and a multiple loop feedback model for the control response of the rider/cycle system. Connections with manual control and vehicle response data are shown. The effects of changing fork geometry, operating conditions, and tire lag properties are discussed. Implications are drawn for handling requirements, vehicle design, and rider control techniques.

The practice and theory of motorcycle steering behaviour are reviewed. The description of the practice relies part on the small amount of scientific experimental work which has been completed and part on the anecdotal. An attempt is made to describe the current state of understanding of the subject particularly from the machine alone point of view, but some discussion of rider abilities and requirements is included. The main references in the field are included, and some indications of how further progress may be made are given.

The use of silicone rubber in OEM ignition cable has grown very rapidly. Because of this rapid growth and the lack of uniform test procedures, a variety of new specifications have evolved. Soon there will be an increased demand for silicone aftermarket cable. Unless something is done now to classify and consolidate these requirements, a profusion of new and unrelated specifications will evolve. This can only lead to confusion, additional cost, and perhaps unsatisfactory performance. This problem can be minimized if SAE J557 is revised to encompass the new requirements.

By utilizing high voltage diodes, a special ignition coil, and a special electronic module, a distributorless ignition system (DIS) having solid state high voltage distribution has been designed and constructed. The ignition coil has two opposite polarity high voltage outputs that alternate in phase upon each firing. Each high voltage terminal is connected to two spark plugs through a pair of high voltage diodes that are arranged in back-to-back polarity. The basic DIS package is suitable for igniting a four cylinder engine. DIS has significant advantages in the areas of RFI emissions, packaging, and “rotor registration”.

Preliminary test results are presented for an S.I. engine which used a focused laser beam and conventional spark ignition as ignition sources. The results show that for a steady running single-cylinder engine with MBT spark timing and fixed throttle position, engine performance and efficiency are improved, extension of the lean limit of operation by 5 air-fuel ratios is possible, and more NO is produced with laser ignition. The effects of EGR are also examined. The CO and HC emissions are essentially the same. With the laser, the spark location was found to have little effect on performance except when it was moved near the combustion chamber wall. The minimum laser pulse energy required for steady engine operation seems to be dictated by the minimum energy required to achieve breakdown of the laser pulse in air at the same pressure.

Scanning electron microscopy and microchemical analyses were conducted to determine the electrode erosion mechanisms of two different spark plugs, platinum-tip and nickel-alloy plugs, tested under various environments. The electrodes were eroded differently depending on the electrode materials and the operating environments. In bench test performed in a dry air pressure chamber, ejection of small molten particles from center electrodes and vaporization loss of side electrodes were the predominant erosion processes. In vehicle tests, the erosion mechanisms varied with the additives in the fuels used. Oxidation of base metal and electrode corrosion by fuel residues were the common erosion processes observed.

A squeal model for a proprietary fixed caliper disc brake is proposed which includes mass and stiffness parameters and allows for variations in the contact configuration of the pad and piston. The predicted and observed trends in squeal behaviour are shown to be in good agreement.