Toyota expects expanding Prius family to define its future

  • 11-Jul-2011 09:05 EDT

Toyota engineers designed the exterior of the Prius v to allow it to be a unique, though obvious, member of the growing Prius family. An extended roofline retains the triangular silhouette symbolic of a Prius.

"Prius has the highest brand awareness of any hybrid vehicle, making it to hybrids what Kleenex is to tissues and Levi’s are to jeans," said Bob Carter, Toyota Division Group Vice President and General Manager, adding that the vehicle "helped set the path for all other hybrids by building consumer trust in hybrid technology."

Toyota's trust in hybrid technology is not now, and will not be in the future, limited to just Prius, with Carter announcing in May that Toyota plans to introduce "10 new models to [its] global lineup in the next 20 months, with six of them entirely new, not next generations of existing models." As tempting as it may be to stop everything, pull out a notepad and pencil, and try to figure out where exactly those 10 new models may show up throughout the Toyota product line, for now the focus is on the immediate entry, the new Prius v.

Carter says that the current Prius enjoys about a 53% market share of the hybrid segment, outselling "all other hybrids combined. Compared to its main hybrid competitors, Prius outsells all Honda hybrids 3 to 1, Ford 5 to 1, and GM 18 to 1."

With such statistics, including 1 million vehicles having been sold in the U.S., and more than 2 million globally, since the Prius first went on sale in Japan 14 years ago, it makes absolute sense that Toyota has (finally) committed to growing its Prius family, "with four distinct members [for] a wide range of buyers," said Carter. "I can see Prius eventually leading Toyota sales in the U.S."

The four Prius members referenced by Carter will consist of the current third-generation Prius that went on sale in June 2009; the Prius Plug-in Hybrid Vehicle (PHV), expected to arrive the first half of next year; a smaller, entry-level model inspired by the Prius c concept vehicle, also expected next year; and, finally, the Prius v (pronounced vee, as it looks), on track for U.S. deliveries this fall.

Members of the Prius family "will all share common Prius attributes but will be unique," said Carter.

In terms of the five-seat v—which some, if specifically not Toyota, refer to as a wagon—part of its uniqueness is the fact that it will offer 58% more interior cargo space than the current Prius and "more cargo space than 80% of all small SUVs on the road today, including the [Chevy] Equinox, [Honda] Element, [Ford] Escape, and [Nissan] Rogue," according to Carter.

Specifically, with the rear seats up, the v offers 34.3 ft³ (970 L) of cargo volume, and 67.3 ft³ (1905 L) with the seats down, eliminating the necessity of owners needing to always have at least one friend with a truck or SUV for moving or camping adventures while increasing spontaneous road trip options.

To get all that extra space, engineers designed the v—which Toyota says stands for versatility—from the ground up, rather than just easing into an elongated version of the current Prius. With its own distinct look but definite Prius DNA, the new, bigger body has a 0.29 coefficient of drag for low air resistance. A continuous surface from the bumper top of the vehicle through to the top of the windshield aids clean airflow.

To balance the new body, engineers chose materials that would keep the Prius v relatively light. The door panels are foam-injected with polypropylene and the deck board with lightweight urethane for weight savings of about 20%. Significant weight reduction was also achieved through the use of high-tensile grades of steel throughout the body along with aluminum panels and systems. High-strength steel sheets and bars used throughout the body ensure a light, though rigid, structure.

Adding to the v's uniqueness, and its enhanced sense of interior space, is a Toyota-first resin Panoramic View moonroof with power retractable sun shades. The optional roof simultaneously offers a more open interior atmosphere while providing a 40% reduction in weight as compared to conventional glass roofs of the same size, as well as enhanced heat-insulation characteristics.

The interior itself is unique to the v, and it includes instrument-panel controls such as a single-dial air-conditioning control and a center-mounted digital combination meter that were designed for ease of use. Also debuting on the v are seats trimmed with SofTex, "a material that weighs half of what typical leather does," said Carter, adding that, in addition to improved durability, the material's other advantage is that "99% fewer VOC [volatile organic compound] emissions are produced vs. conventional synthetic leather during the manufacturing process."

Not so unique to the v is Toyota's Hybrid Synergy Drive, though it was adapted for the v. It still uses two motors, one a 60-kW unit that primarily powers the transaxle, and the other a smaller motor that works primarily as an electric power source.

One difference is in the 1.8-L, 98-hp (73-kW) engine. An improved exhaust gas recirculation system features a newly designed heat exchanger that provides for better cold-weather performance by reducing the time for coolant to reach operating temperature. This feature allows for more efficient operation by shortening the time before the gasoline engine can stop upon cold start.

Another minor change is in the nickel-metal hydride battery pack. It was redesigned to be more compact, allowing its cooling duct to be located under the rear seat. This seemingly minor design change is one of the contributors to the doubling of cargo volume in the v over the current Prius.

But the decision to stay with NiMH technology, and not switch to Li-ion, in the U.S. market, at least for now, had more far-reaching results than Toyota could have possibly anticipated: while the v's counterpart in Japan, the Li-ion equipped Prius Alpha, was delayed in Japan due to the aftermath of the March 11 earthquake and tsunami, the ample supply of NiMH batteries has not affected the fall delivery of the v. Also, according to Carter, there is not currently a cost benefit to using Li-ion in the U.S.

Also new is Pitch and Bounce Control, which uses the torque of the hybrid motor in combination with suspension enhancements such as wheel-speed sensors to suppress bounce and toss motions and improve ride.

Because the Prius v is likely to carry more loads and passengers than the standard Prius, its front coil-over spring and damper capacities have been significantly increased and a new upper support has been designed. The steering gear has been attached to the front suspension member, and the stabilizer bar repositioned for more responsive steering feel and enhanced ride comfort.

In the rear, a torsion-beam suspension design has been fitted with appropriately tuned springs and dampers. The new rear-suspension system is designed to help ensure stability and ride comfort, and it has a lower mounting point to improve luggage space.

The Prius v is expected to deliver estimated EPA fuel economy ratings of 42 mpg city, 38 mpg highway, and 40 mpg combined, "the best fuel economy ratings of any SUV, crossover, or wagon on the market," according to Toyota, while emitting "66% fewer smog-forming emissions than the average new vehicle."

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