I found really impressive figures to describe the direct injection system. Dr. P.J.Bowen, really impressed me with the details about direct injection system. You can find more detail about his research and direct injection system at http://www.cf.ac.uk/engin/staff/pjb/. The direct inejction system technology is claimed be the best technology to increase engine performance. Gasoline direct injection system (GDI) was first implement by Mithsubitshi in 1986. But the direct inejction technolgy really boost the diesel engine as high compression ratio is implied to the engine.