A showroom debut for Toyota’s new fourth-generation Prius, initially expected in mid-2015, may now be as far off as early 2016.
A report this week with industry paper Automotive News suggests Toyota engineers have returned to fine-tuning the hybrid’s platform and powertrain - pushing production back by around six months.
The specific cause of the setback is unclear, although the report claims that a source close to the project has confirmed that Toyota is working to further improve the new model’s fuel economy.
In its current form, the Australian-delivered third-generation Prius lists fuel use at around 3.9 l/100km. TMR testing, in regular driving, returned 4.2 l/100km.
The third-generation model is driven by Toyota’s familiar Hybrid Drive system, pairing a 1.8 litre Atkinson-cycle petrol engine with a 60kW electric motor.
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In its next generation, the Prius is expected to again function as a testbed for crucial new technologies that should eventually star in more Toyota and Lexus models.
The new Hybrid Drive system is expected to be both smaller and lighter than in its current form, while returning at least a 10 percent improvement in fuel economy.
A January interview with Toyota R&D boss Soichiro Okudaira claimed the team was still considering whether to a nickel-metal hydride or lithium-ion battery arrangement, although the project is likely to be beyond that stage now.
The Prius range’s electric system has been powered by nickel-metal hydride batteries since the first generation launched in 1997, although the current Prius Plug-in Hybrid EV uses lithium-ion.
Lithium-ion batteries have become prevalent in recent years, thanks to their lightness and energy density compared to nickel batteries.
A new Toyota Global Architecture will also underpin the new Prius, increasing the number of common parts across the company’s models.
Last year’s Tokyo Motor Show also saw Toyota global design boss Simon Humphries promise a more compelling design for the new Prius.
"It has to be a revolution this time around," Humphries told Automotive News.
"The last redesign was evolutionary, and when stylists try two evolutionary designs in a row,” he said, "things go wrong. That's kind of like an unwritten rule."
If nothing else, moving to a design with more mainstream appeal would go a long way toward satisfying Toyota boss Akio Toyoda's demand for more "emotional" models.
Humphries offered little in the way of a hint for what’s to come, but we could see a concept within the coming year.