This month's briefing is the latest of just-auto's regular in-depth look at the top 20 engine families worldwide in 2006. Engines are much easier to organise into families than platforms, and as such all vehicle manufacturers have a series of high-volume engine families. The report explains which engines are covered by which family and where possible, considers how they are likely to evolve in the future. Tables in the report show top 20 engine families by production volume, ranked by 2006, data for 2004, 2005 and 2006 (units) and their largest model application.