What does HDI mean?
HDI = High pressure Direct Injection
Peugeot has worked ceaselessly over the past decades to develop its reputation as the worlds leading manufacturer of diesel engines. It comes as no surprise, therefore, that Peugeot should have used the latest Common Rail technology to create a high-pressure direct-injection motor known as the HDI.
HDI: Under this system, the fuel is injected under high pressure directly into the combustion chamber. The HDI badge, therefore, identifies both this new type of engine and those cars in the Peugeot diesel range that are equipped with the HDI system.
The first model in the Peugeot range to incorporate HDI technology is the 406. The HDI engine is available on other Peugeot vehicles worldwide but only available on 307 and 406 in South Africa.
http://www.peugeot.co.za/faq/