Comments on: Dyno-testing engines http://www.ret-monitor.com/articles/389/dyno-testing-engines/ Specific mission-critical info for professionals Thu, 09 Feb 2012 16:38:22 +0000 http://wordpress.org/?v=2.7.1 hourly 1 By: Terry http://www.ret-monitor.com/articles/389/dyno-testing-engines/comment-page-1/#comment-6171 Terry Sat, 22 Jan 2011 06:53:01 +0000 http://www.ret-monitor.com/articles/389/dyno-testing-engines/#comment-6171 The results of testing on a dyno are only as valid as the load conditions the dyno is commanded to place on the test hardware. A recip piston engine does not output a uniform torque during a given 360deg rotation of the crank. The instantaneous peak-to-mean torques the gearbox is subjected to can vary by 200%, depending upon the engine's number of cylinders, BMEP rates, and polar inertias. The gearbox components must be able to handle these transient torque loads. With regards to an F1 gearbox, one important thing the dyno doesn't simulate are the chassis loads the gearbox housing is subject to. Gear meshes don't like any misalignments. This results in tooth edge loading and high contact stresses. Even misalignments as small as .001 or .002 inch across the gear face will cause problems. Maybe one of these days, some clever F1 engineer will come up with a way to provide some method of strain isolation between the gearbox internals and the stressed housing, without adding excessive weight or volume. The results of testing on a dyno are only as valid as the load conditions the dyno is commanded to place on the test hardware. A recip piston engine does not output a uniform torque during a given 360deg rotation of the crank. The instantaneous peak-to-mean torques the gearbox is subjected to can vary by 200%, depending upon the engine’s number of cylinders, BMEP rates, and polar inertias. The gearbox components must be able to handle these transient torque loads.

With regards to an F1 gearbox, one important thing the dyno doesn’t simulate are the chassis loads the gearbox housing is subject to. Gear meshes don’t like any misalignments. This results in tooth edge loading and high contact stresses. Even misalignments as small as .001 or .002 inch across the gear face will cause problems.

Maybe one of these days, some clever F1 engineer will come up with a way to provide some method of strain isolation between the gearbox internals and the stressed housing, without adding excessive weight or volume.

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