By Jack Rosebro
|The Camry Hybrid is distinguished from its four non-hybrid cousins by its grill.|
During the third annual SAE (Society of Automotive Engineers) Hybrid Symposium which wrapped up Thursday in San Diego, Toyota’s Dave Hermance briefed engineers on the upcoming 2007 Camry Hybrid, and shed a bit more light on the thinking behind the vehicle’s position in Toyota’s growing hybrid lineup.
Economy hybrids are designed for efficiency by downsizing the engine—witness the 1.5-liter engine which resides in the otherwise Camry-sized Prius. “Hot-rod” hybrids such as the Honda Accord, Toyota Highlander, and Lexus RX400h mate a more powerful V6 to a hybrid drive. Hermance explained that although the Camry hybrid is a less radical economy hybrid than is the Prius, the Camry is an economy hybrid nonetheless.
The 2007 Camry hybrid (earlier post), now scheduled to be released in May, uses a 147-hp version of the standard Camry’s base 2.4L engine, optimized to reduce the amount of energy which is wasted.
As with the Prius, the hybrid Camry’s engine uses Toyota’s version of an Atkinson-cycle engine, delaying the closing of the intake valves to create an engine with a high 12.5:1 expansion ratio paired with a conventional 9.6:1 compression ratio.
Although Toyota’s newest hybrid does not incorporate the broad array of fuel-sipping technologies employed by the Prius—for example, its 244.8V battery is heavier and it does not use a coolant heat storage system to keep hot engine coolant available for up to three days, as does the Prius—this Camry is Toyota’s first HEV that is arguably positioned close enough to the Prius to compete for some of its market share.
Asked by Green Car Congress if the hybrid Camry’s introduction now paves the way for a redesign of the Prius with even more radical technologies, Hermance replied, “Absolutely.”
A quick look at hybrid vehicle technologies under consideration throughout the industry gives an indication of the potential improvements that Toyota might consider. Assuming that safety concerns can be satisfied, a lithium-ion battery pack is an obvious consideration; however, as some Green Car Congress readers have noted in the past, it’s possible that the battery pack could be combined with a smaller set of ultracapacitors to handle short bursts of acceleration.
Secondary battery pack charging systems, using either photovoltaic solar panels on the roof of the vehicle or a thermoelectric device to recapture some of the internal combustion engine’s waste heat, are also increasingly popular on the motor show circuit. Toyota themselves recently displayed a version of its Japan-only Estima hybrid minivan with a thermoelectric device built in to the vehicle’s engine exhaust system.
Given that flex-fuel vehicles seem to be gaining traction almost daily, the Prius is an obvious candidate for such treatment, as long as it does not interfere with the vehicle’s coveted California AT-PZEV certification. Finally, the Prius remains a heavier vehicle than most comparably-sized non-hybrid vehicles—and that’s a data point that Toyota is almost certainly anxious to reduce, as long as it can do so without significantly affecting the cost of the vehicle.
The Prius is scheduled for replacement in 2008, with the next generation to be sold as a 2009 model-year vehicle.
While Toyota had steadfastly maintained that the hybridized Camry would use a four-cylinder engine, multiple sources inside Toyota’s American operations had maintained that a V6-powered hybridized Camry was on the way, as well (earlier post).
A Toyota official at the symposium attributed those remarks to a belief within the company that Toyota would use the hybrid Camry to compete directly with Honda’s Accord hybrid. According to Hermance, Toyota has no such plans.
Although most US-market Camry hybrids will be built in Toyota’s manufacturing plant in Kentucky, the first Camry hybrids sold in the US will be built in Japan. Toyota projects that up to 4,000 Camry hybrid will roll out of Kentucky every month, with an additional 4,000 per month available from Japan, if need be.