Search Results

In the design of automotive and heavy equipment engines, accurate analysis of factors which influence immediate and long-term effects is essential. Fastener torque, thermal and pressure variations are utilized to evaluate basic sensitivity of the engine to these parameters by measurement of cylinder bore and cylinder head distortions. Holographic interferometry was used to measure the cylinder deformation caused by the applied thermal and mechanical loads. A cast iron V-6 engine was used as the test engine. Influences of bolt torquing, as would occur during initial assembly and/or service were evaluated. Pressure on the cylinder walls was simulated by creating a vacuum in the water jackets of the engine block. The effects of thermal loads were evaluated using a temperature controlled liquid flowing through the water jackets. Incremental steady-state loads were applied to investigate the deformation of the engine at specific points in the operating cycle.

An important factor influencing the strength of spur gear teeth is the fillet profile. In the fillet area bending stress and local geometry changes result in stresses and stress concentrations that can, under high loading conditions, lead to failure. This study was conducted to determine if an optimum fillet profile existed, what the shape of the optimum profile is, if the profiles are similar for different pressure angles and the magnitude of improvement that could be expected. New manufacturing techniques such as full-form grinding, near net formed gear blanks and powered metallurgy technology allow the gear designer to put different forms in the root area than the usual trochoid produced by the tip of a hob generating the gear. With the application of these techniques the fillet profiles could be optimally formed leading to strength improvements of up to 40%, with reductions in rotating mass.