Third Generation Prius
— copy and photos by Ralph Birnbaum
Love it or hate it, the Toyota Prius is the stereotype for emerging alternative automotive technologies. With a trend setting hybrid drive system that blends electric and gas engine power through an ingenious transaxle, the Prius has done something that other OEMs have only dreamed about: they've sold a million plus copies worldwide, and counting.
It looks like the singles hitters at Toyota have decided not to swing for the fences with a big EV breakthrough, satisfying themselves with fine tuning and minor enhancements in this latest iteration.
The Third Generation Prius is loaded with tweakings and modifications. No breathtaking technological bustouts here; only a mountain of fine tuning. The sheetmetal is rearranged to reduce the coefficient of drag a smidgen, from 0.26 to 0.25. Improved rear seat headroom means that you can now take moderate sized adults for a ride without causing them severe neck pain.
We eavesdropped at the auto show to conduct an admittedly unscientific poll on the latest design from the School of Nerd, with responses ranging from, "That thing is an assault on the senses," to a wildly enthusiastic, "It aint too bad."
The new Prius has a larger gas engine than its predecessor, bumping the displacement from 1.5 to 1.8L, increasing its horsepower from 76 to 98. Still using the Atkinson combustion cycle, the bigger breather flexes its added muscle to actually reduce fuel consumption, with overall economy rising another smidgen, from 49 to 50 mpg. Combined gas and electric propulsion systems now generate 134 hp.
The new Prius engine is beltless. Both the ac compressor and water pump are electric, and the ac can be started from across a parking lot with a new key fob to cool the car, without the engine running. Operating accessories only when they are needed reduces the constant parasitic horsepower losses associated with belt-driven pumps. The crank pulley—like the human appendix—is a holdover from an earlier evolutionary stage.
According to Toyota, the new CVT drive system is lighter, with reduced slippage.
The exhaust heat recirculation system warms the engine coolant faster after cold starts for improved engine efficiency and speedier cabin warming. When it comes to passenger comfort, this EGR helps Everyone Get Roasted.
The rear drums are gone, with four-wheel disk braking now standard. The regenerative braking system has been tweaked for improved efficiency. With the rear brakes getting little use, expect to find a service opportunity cleaning brake assemblies that seize from inactivity. In fact, my guess is that this intricate lever and pivot system, lovingly crafted by a crack team of Toyota engineers, will be totally locked up here in Ohio in less time than it takes to say, "road salt."
The battery pack and related components have also been redesigned to increase trunk space, but just barely. The improved battery pack can operate the Prius in pure EV mode; a little. Before you get too excited, EV range limited to a mile or two at low speeds. It ain't no Tesla, folks.
Toyota is also touting improvements to the suspension system for better ride and handling. This is certainly one area where the Prius has a lot of room for improvement.
Like Ford, Toyota is using plant fiber, ecological plastics in seat cushion foam and some exterior trim pieces.
Here are more Prius tech highlights:
• The inverter has a direct cooling system.
• The inverter, motor, and transaxle are 20 percent lighter.
• There are three driving modes: EV - for a mile or so under favorable conditions; Power Mode; and Eco Mode for best fuel economy.
• The front A pillar moves further forward.
• Roof profile altered to increase rear seat headroom by 3.9 inches.
• Optional solar roof panel powers an electric ventilation system.
• LED lamps reduce power consumption.
• Built on new platform.
• Increased front wheel caster angle.
• Aluminum hood.
• Hgh tensile steel in strategic structural areas.
• Added interior storage.
• Touch Tracer sensors on steering wheel display images on instrument cluster for easy viewing by driver.
• ECO indicator helps driver operate vehicle for best fuel economy.
• SRS airbags, knee bags, and side air curtains are standard.
• Active headrests in both front seats.
• EBD (Electronic Brake Distribution)
• BA (Brake Assist)
• TRAC (traction control)
• VSC (Vehicle Stabilty Control)
• Dynamic Radar Cruise Control (option)
1.8-liter four-cylinder engine with VVT-i
Engine horsepower: 98 hp @ 5,200 rpm
Engine torque: 105 lb-ft @ 4,000 rpm
Electric motor: Permanent magnet synchronous motor
Electric motor power output: 80 hp/153 lb-ft torque
Hybrid system net horsepower: 134 hp
Emission rating: SULEV (with AT-PZEV)
Transmission: Electronically controlled continuously variable
Drive System: Front-wheel-drive
Hybrid battery pack: Nickel-metal hydride
Estimated fuel economy: 50 mpg (combined)*
Overall Length: 175.6
Overall Width: 68.7
Overall Height: 58.7
Ground clearance: 5.5
Coefficient of Drag: 0.25
Wheels: 15-inch alloy wheels - 17-inch alloy wheels (optional)
Tire Size: 15-inch: 195/65R15 - 17-inch: 215/45R17 (optional)
Seating Capacity: 5
EPA class rating: Midsize