IHI developed RHF type turbocharger dedicated for performance improvement of light duty vehicles, which is also designed for fully automated full-scale mass production, and began series production in 1991. RHF type turbocharger evolved time to time employing new structures, pursuing the improvement of transient response and fuel consumption. In the late 1990s, together with market penetration of common rail fuel injection systems developed for diesel-powered vehicles, turbochargers are increasingly installed to achieve improvement of both power and drivability while meeting the challenges of better fuel economy and cleaner exhaust gas emission. In response to the changes in the market, IHI released RHF4V type turbocharger with variable geometry mechanism in 1999.