The Audi Q5 has been a strong seller for VW's luxury brand, which contributes a big portion of VW's global profits. Photo credit Audi

Volkswagen (NASDAQOTH:VWAGY) surprised analysts with stronger than expected second-quarter earnings, as booming sales of luxury cars and some new cost-saving technology helped offset sluggish sales in some parts of the world.

VW's pre-tax profit of about $4.6 billion dollars was up almost 5% from what the German giant earned in the second quarter of 2012 -- and VW's profits last year led the industry's. In this video, Fool.com contributor John Rosevear takes a closer look at the two key factors contributing to VW's strong quarter -- and at the company's prospects for another big full-year profit.