Toyota Camry Hybrid sedan earns 40 mpg with electric boost
Bob Plunkett, Tue, 31 Oct 2006 08:00:00 PDT
MONTECITO, Calif. -- The slinky mid-size sedan we're steering up San Ysidro Road in California's mega-bucks community of Montecito looks cool with a sweeping curved profile featuring a racked-back windshield and arching roofline which descends to the high-decked tail.
A dominant face presents a broad grille scored with body-colored fins and a low intake valence stretched from corner to corner, plus canted lamp clusters of an irregular format mounted at the top of front corners with projector-type low-beam lamps drilling round points in shimmering acrylic caps.
Stylish lines etched into the package of what appears to be a conventional four-door sedan actually conceal complex mechanisms which make this vehicle quite special. It's a new high-mileage hybrid electric vehicle (HEV) from Toyota which carries a carload of sophisticated hardware and computerized electronic controls.
Toyota labels it as the Camry Hybrid, HEV version of the best-selling passenger car in America. Automotive designers from Toyota in the United States and Japan conspired to reinvent the Camry for model-year 2007, and the new design -- restructured and expanded with concerns for passenger comfort and personal safety foremost in mind -- spins off a HEV variation which earns high fuel economy scores because it packs aboard not one but two motors.
There's a thrifty but conventional 2. 4-liter four-cylinder Atkinson-cycle engine which operates on gasoline plus a battery-powered electric motor of permanent-magnet design. Toyota adds its high-voltage and high-torque Hybrid Synergy Drive (HSD) system to control all energy produced by the two plants and apply it directly to the front wheels in infinitely variable measures through an electronically-controlled continuously variable transmission (CVT).
Camry in this hybrid edition can run on the gasoline engine or on the electric motor, or in a mode with both plants contributing power simultaneously. Virtually silent at start-up with only the electric motor switching on, Camry the HEV will surge forward on command with initial help from the electric motor and the gasoline engine not actually firing up until the vehicle moves faster than three miles per hour.
At highway speeds the gas engine does most of the motivating, while in reverse gear it's the electric motor that handles all of the work. The four-cylinder gasoline-fired plant, with dual overhead cams and Toyota's smart variable valve-timing (VVT-i) system, develops 147 hp at 6000 rpm plus torque of 138 lb-ft at 4400 rpm. The electric motor, coupled to a nickel-metal hydride battery, makes 105 kilowatts of power (the equivalent of 45 hp), with torque amounting to 199 lb-ft available from zero to 1500 rpm.
Toyota estimates the combined effect of the gas-fired engine and electric motor tallies to 187 hp. Net effect is a driving range which may exceed 600 miles and fuel economy numbers up to 40 mpg but with no detectable sacrifice of engine power for off-the-line accelerations or passing in the quick lane. In a switch from convention, Camry as a HEV achieves better fuel efficiency when plowing city streets in start-and-stop traffic rather than when cruising at a swifter pace on a highway.
That's because its gas engine works at higher speeds, while in city traffic with frequent stops the electric motor takes over. Power from the gasoline engine is utilized in two different ways. One portion of this energy is used to turn the front wheels, while another portion powers an electric generator that runs the electric motor, which in turn sends the supplemental power to the wheels.
Stomp the accelerator to romp into a passing lane and the electric motor adds an extra boost, yet for such a heavy demand of power the operating energy for the motor comes directly from a bank of on-board batteries. Internal recharging occurs either during braking, when the gas engine operates as a generator, or when the electric generator does the recharging job. Thus, Camry Hybrid never needs to be plugged in for recharging as would a purely electric vehicle.
A video screen, centered high on the dashboard atop the central stack of audio and climate controls, illustrates operations for the energy management system with icons representing the gas engine, electric motor, drive wheels and battery. Arrows depict the energy flow, with one running from the engine or motor to the wheels when either plant supplies power, or another flowing back to the motor and on to the battery when recharging occurs. Driving Camry Hybrid becomes a high-tech experience.
A remote transmitter fob takes the place of an ignition key, as the smart car will recognize a driver by the proximity of the transmitter. Simply slip into the bucket seat and punch the power button on the dash. The electric motor switches on silently, as confirmed by a green light.
hen control the transmission through a console-mounted joystick that's electronically linked, as is the throttle, the steering system, even the brakes. On tap to help stop the vehicle are disc brakes tied to the anti-lock brake system (ABS) with electronic brake-force distribution (EBD) and Toyota's advanced vehicle stability control system, labeled vehicle dynamic integrated management (VDIM). Camry's cabin is an efficient design and shows improvements in styling and the tone of materials, with comfortable seats in place and useful instruments and controls plus lots of standard equipment aboard.
The layout includes a pair of buckets up front flanking a center console and a rear bench built for three but scooped for two. The area is surrounded by hidden air bags -- up-front inflators for front seats plus seat-mounted side air bags and one more to shield the driver's knee, then curtain-style air bags tucked above side windows front and back. Camry Hybrid comes with extensive standard features -- power controls for windows and door locks and mirrors, eight-way power for the driver's seat, Optitron gauges, twin-zone climate controls and a premium AM/FM stereo kit with six-disc CD changer and eight speakers.