Design Concept and Manufacturing Method of a Lightweight Deep Skirt Cylinder Block 2012-01-0406
An engine cylinder block is generally considered to be the heaviest part within a complete engine. In lowering the fuel consumption and CO2 discharge to the environment, efforts have been made around the world to reduce the weight of cylinder blocks. In general, the efforts are mostly focused on material upgrade from either cast iron to aluminum or from aluminum to magnesium. Although the material upgrade approach is effective in lowering the part weight, it is often accompanied by undesirable cost increase and manufacturing complexity. In moving forward, a new cylinder block concept is proposed that focuses more on material removal rather than material upgrade. The material removal approach is focused more on the high metal concentration areas like the bulkhead, skirt and housing for water pump and thermostat. To ensure that the material removal approach is effective and suitable for mass production, a uniquely designed crankcase inner sand core is applied. In addition, a radical crankcase skirt design is used to achieve small overall size to significantly reduce the metal volume while at the same time increasing the skirt's rigidity and strength. In ensuring that the cylinder block is integrated well with other parts of the engine, other parts like the design of crankshaft, bearing beam, thermostat housing and auxiliaries are also optimized to match the enhancements made to the cylinder block. In studying the concept's effectiveness in reducing the part weight, a cast iron 1.6 liter cylinder block and the related components are designed and modeled in Catia V5. The 3D models are later used for weight comparison with an existing 1.6 liter cast iron cylinder block currently in production.