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A new concept in thrust washers for gasoline and diesel engines has been developed. Traditionally, thrust washers have been made from the same steel-backed bimetal or trimetal materials that are used for connecting rod bearings and crankshaft main bearings. The new concept is a solid aluminum alloy, specifically formulated for optimum performance as a thrust washer material. This alloy has environmental advantages and performance characteristics superior to currently used materials. The composition, manufacturing process, and microstructure of the new concept thrust washer are briefly explained, and the performance characteristics and environmental advantages are presented.

Bore distortion was measured in a 2.0 liter in-line 4-cylinder gasoline engine, chosen because its siamesed bore design was expected to incur high bore distortion. The method adopted was to install 10 Micro-Epsilon eddy-current transducers in an invar carrier attached to the under crown of the piston. The transducers emerged through apertures in the piston at second ring level where they were in close proximity to the bore surface. A 2-beam linkage system was used to carry miniature co-axial cables to the engine exterior. Measurements were recorded at various speeds and loads up to 6000 rev/min. Maximum bore distortion was 86 microns, arising from clamping loads, thermal effects and combustion pressure. The head bolts spaced around the bore gave rise to fourth order distortion, but the dominant influence was thermal loading which induced second order distortion, attributed directly to the siamesed bore design. The combustion pressure proved to have the least influence.

Gasketed bolted joint analysis tools are gaining importance as the market place demands superior product performance, reduced cycle time, and lower cost. Design analysis tools can be used to predict product performance over the life of the joint. Numerous design concepts under a range of operating conditions can be simulated. The optimal designs can be determined before a prototype is manufactured and tested. The reduction in prototyping and testing results in cost savings and a reduction in design time. The customer is provided with a product with superior sealing performance at a lower cost. This paper presents a design analysis technique which uses a non-linear finite element program in conjunction with a spreadsheet. The spreadsheet functions as a user friendly input and output interface to the finite element program. Parametric models are used to define the geometry of standard sealing system components that include gaskets, flanges, and fasteners.

Standard bonded transmission piston design specifies the use of low carbon steel for the piston carrier material. High strength low alloy (HSLA) steel is proposed for applications where load and packaging requirements dictate. The impact of carrier material selection on piston design and manufacturing needs to be comprehensively evaluated in these cases. This paper will discuss considerations for using HSLA steel and make recommendations for its application to bonded transmission pistons.