360° vs. 270° vs. 180°: The Difference of Balancing a 2 Cylinder Inline Engine: Design, Simulation, Comparative Measurements AVL LIST GmbH

Format:

Conference/Event

Author/Creator:

Hubmann, Hubmann, author.

Contributor:

Friedl, Hubert

Graf, Bernhard

Schoeffmann, Wolfgang

Conference Name:

2012 Small Engine Technology Conference & Exhibition (2012-10-16 : Madison, Wisconsin, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2012

Summary:

Beside the automotive industry, where 2-cylinder inline enginesare catching attention again, twin-cylinder configurations arequite usual in the small engine world. From stationary engines andrange-extender use to small motorcycles up to big cruisers andK-Cars this engine architecture is used in many types ofapplications. Because of very good overall packaging, performancecharacteristics and not least the possibility of parts-commonalitywith 4-cylinder engines nearly every motorcycle manufacturerprovides an inline twin in its model range.Especially for motorcycle applications where generally theengine is a rigid member of the frame and vibrations can betransferred directly to the rider an appropriate balancing systemis required. A 360° parallel twin engine does generate both: free1st order mass forces and free 2nd order mass forces. 1st ordermass forces can be compensated by a balancer shaft which is themost common, the implementation of a reciprocating balancer weightwould eliminate both but has certain drawbacks like complexity,friction and additional excitations.A 180° crank-pin offset does produce 1st order mass-moments andfree 2nd order mass forces. In addition to that an uneven firingorder gives drawbacks in orifice noise and excitations in otherorders.The option of a 90° crank-pin offset in an inline 2-cylinderengine features a design, without free 2nd order mass forces on theone hand but small mass moments and an uneven firing distributionon the other hand.This paper investigates the difference on the NVH behaviorbetween 360°, 270° and 180° inline 2-cylinder engines by the meansof design and engine mount simulations and shows the comparativeresults of structural vibrations, airborne noise and orifice noiseof these 2 versions having the same basic design and enginespecifications measured on an acoustic chassis dynamometer

Notes:

Vendor supplied data

Publisher Number:

2012-32-0106

Access Restriction:

Restricted for use by site license