Abstract
Keywords
Connecting Rod, Bearing, Cap, Lightweight, Engine, design
Abstract
Use of lighter or compact reciprocating engine components such as pistons and connecting rods has always been a desirable target for engine designers. Small savings in mass and geometry here can result in very significant knock-on benefits such as a reduction in total engine packaging dimensions and weight.
The first part of the paper discusses a theoretical study on design arameters that might influence big end bearing performance carried out using the SABRE software programme developed by Glacier Vandervell Bearings. The results of the lubrication study of simplified geometries concluded that housing conformability can be favourable when applied to the cap for inertia loads but potentially detrimental when applied to the stem/big end blend.
The second part of the paper outlines the results of a development programme that took big end design to radical limits. An integral bearing cap with a thickness under 2.5mm gave total rod weight savings of over 45% as compared to an existing best-in-class design. Results from high speed engine tests are presented together with problems encountered during the programme.