PSA Peugeot Citroen, along with BMW, jointly developed the Mini's gasoline-fed engine and, until recently, PSA's diesel mill could be found under the bonnet of the little Cooper as well. With motivation partly provided by PSA, the Mini Cooper hit the streets running and never looked back. It was a smash hit, with sales exceeding most expectations.
Recently, rumors about a possible diesel hybrid Mini have swirled around and it would seem like a match made in heaven to pair up PSA's Hybrid4 system – due to appear soon in the 3008 and 508 – with the pint-sized Mini. Though there's no doubt that the resulting vehicle would be highly efficient, Mini's head of diesel engine development, Wolfgang Kuttler, states that the Hybrid4 setup is "a very expensive and heavy system." Kuttler added:
Our hopes of a Mini diesel hybrid may have been dashed, but Kuttler believes that improved efficiency is still on the horizon. According to Kuttler, Mini will focus on extracting every last bit of efficiency from its current diesel engines. Kuttler presented Mini's diesel plans this way:It only brings fuel savings in town, not on the faster, more open roads commonly used in Europe. We'll never use a system like it at Mini for that reason.
If Mini can build a diesel engine that will top the company's 60.3 miles per gallon-rated (U.S) mill found in the Mini One D, then there's probably no need for a diesel hybrid anyways.I believe that we are currently getting about 50 per cent of the efficiency available in diesel engines. We intend to concentrate on improving ancillary drive, lowering internal friction, increasing injection pressure and optimising turbo response, among other aspects. Variable valve timing is a possibility but it's low down on the priority list.