It may not be too long before you can purchase a car which really does run on the smell of an oily rag. Toyota’s engineers claim that plug-in versions of its Prius are achieving an incredible 65 MPG (which works out to 3.6 l/100 Km).

Although the technology is being developed for introduction in the recently revealed third generation Prius, the test data has been gathered in modified versions of the second generation car. Running a lithium ion battery pack, instead of the standard metal hydride unit, allows the cars to travel further on a charge before calling on back-up from the petrol engine.

The new Prius, first shown at the Detroit Motor Show in January, is due to go on sale around the world later this year. Initially it will launch with a modified version of the current car’s battery system. Toyota however claims that any of its hybrid range will be suitable candidates to make use of Plug-In Electric Vehicle technology.

At this stage Toyota has no confirmed production schedule for the plug-in Prius, or a plug-in version of any of its other hybrid cars. With the coming Chevrolet Volt due in 2010 however, Toyota won’t allow itself to lag too far behind in bringing this technology to market.