Unit injection systems running biofuels
DBT Diesel engine specialist biofuels page
Scnell, who make high quality bio-gas gensets - they claim 25% of world market - offer gensets that are also vegetable oil compatable. Very nice looking kit high quality engines that they fit out with their own combustion sensing electronic unit injection system.
Article about Scnell on page 35
Wolf have been modifying VW PD engines to run single tank PPO since 1999
Elsbett offer single tank PPO modification kits and a fitting service for some VW PD engines]