Diesels typically have good fuel economy, but hot on the heels of the Volkswagen affair, Australia is set to tighten the rules for diesel car emissions - which will put a dent in engine performance.
Can VW rebuild public trust? Its survival may depend on repairing the image damage caused by deception over clean diesels.
Current clean diesel technology is more than capable of meeting tough air quality rules while still delivering excellent fuel performance. Biofuels could make it even cleaner.