- Doors and Seats
5 doors, 5 seats
- Engine
1.5i/50kW Hybrid, 4 cyl.
- Engine Power
132kW (comb), 400Nm
- Fuel
Hybrid (91) 4.4L/100KM
- Manufacturer
FWD
- Transmission
Auto (CVT)
- Warranty
3 Yr, 100000 KMs
- Ancap Safety
5/5 star (2009)
Toyota Prius
There's nothing at all unusual about the ignition key of Toyota Prius. It works just like a normal car. But twist it to the Start position and ... silence. All that happens is that the central instrument cluster displays a single word: "Ready".
But is the world ready for the Prius, the most succesful eco-car yet? Toyota plans to sell it here - perhaps priced as low as $35,000 - some time in 2000.
The simple answer is that the world doesn't need to be ready. The Prius is an example of what research and development boffins call transparent technology.
The hybrid-powered Toyota may be jam-packed with innovative engineering, but it is no more difficult to drive than an automatic Corolla - even though it delivers double the fuel efficiency, which means halved output of the greenhouse gas carbon dioxide, and has smog emissions one-tenth those set by the Australian government.
With the helpful "Ready" light glowing, grasp the shift lever protruding from the dash beside the steering column, thumb the button on the end of its handle and pull it down into the "D" position. Release the foot-operated parking brake and the Prius is ready to roll. And still not a peep from the engine bay.
Tentatively apply pressure to the accelerator and, sure enough, the Toyota begins to move. At first it's spookily silent, because the electric motor that's providing this initial shove to get the Prius going is hush-quiet. At about 20-25 km/h the 1.5-litre four-cylinder petrol engine fires up.
But it's easy to miss this significant event. It starts without a tremble or tremor. The muted but unmistakable sound of internal combustion is the only palpable sign that Prius has begun burning unleaded.
The Prius doesn't change gears like a conventional automatic. So there's none of the usual sensation of shifting, where a slight jerk signals that the transmission has picked another gear ratio. Nor, obviously, does the engine sound rise and fall sharply.
The planetary gearset that allows the petrol engine and electric motor to share the job of propelling the Prius also functions as a continuously variable transmission, adjusting the relationship between road speed and engine speed with absolute smoothness.
Red light ahead. Ease off the throttle pedal and the sound of the engine fades.
A subdued whine takes over, the sign that the Prius is using regenerative braking - in simple terms, converting the motion of the car into electricity creates drag which slows it down - to help replenish the 70 kg nickel metal hydride battery pack that is right behind the backrest of the rear seat.
It isn't really necessary for the Prius driver to know what the car's petrol-electric hybrid system is doing at any particular time. The important thing is that its 50-litre fuel tank will deliver more than 1,000 km of city driving between refills, even if it cannot match the car's official Japanese government fuel consumption test figure of 3.6 litres/100 km.
There is, however, a way to keep track of the action. The Prius has a colour LCD screen in its dash, between the central face-level air vents. In Japan the screen functions as a control panel for the audio system, a clock and a warning system, and accommodates the optional satellite navigation system.
But the screen can be set to display an energy flow diagram of the hybrid system. The animated graphic, inset right, shows whether the Prius is getting along on electric power only or a blend of electricity and petrol.
It also shows whether a portion of the engine's power is being used to recharge the battery pack and whether regenerative braking is helping recharge the battery. The battery's state of charge is displayed.
It's fascinating ... and probably a greater hazard to safe navigation than using a mobile phone.
And that's it for novelty. Aside from aural oddness, unusual transmission and distracting energy flow display, the Prius is quite normal.
Performance is adequate rather than exhilarating. Toyota claims the Prius takes 12-odd seconds to get from standstill to 100 km/h. This is similar to a Corolla automatic, though the Prius is brisker to 60 km/h and slower from there to 100 km/h. Top speed is 150 km/h, but only for a matter of minutes. The maximum speed which can be sustained without draining the battery is more like 140 km/h.
On suspension tuned for maximum appeal to Japanese drivers, the hybrid Toyota's ride is pillowy soft and very absorbent. It would be more comfortable on Australian roads with firmer shock absorbers. Thanks to the suspension settings, the Prius rolls heavily when cornering. Despite narrowish, low rolling resistance, fuel-saving Bridgestone tyres, roadholding is acceptable. And the Prius responds quite predictably to its electric assisted power steering.
The interior, aside from the unusual dash with its strip of digital instruments, LCD screen and array of chromed buttons, is typical Toyota: thoughfully designed, very well built and using the full palette of greys. Most convenience features that buyers of upmarket small Japanese cars expect are there - tilt-adjustable steering column, height-adjustable seat, power windows and mirrors and a bunch of storage compartments.
With the battery pack in the way, the rear seat backrest can't fold forward to increase boot space. Toyota compensates for the loss of versatility with a Volvo-esque built-in child seat. The boot is quite roomy, and tall rather than long.
But the Prius's practical, familiar feel disguises the immensity of Toyota's achievement. The depth and breadth of the engineering and development talent behind this little car are awesome.
To appreciate the Prius properly requires a passing acquaintance with the laws of physics. Specific-ally the one which covers the conservation of energy. For those who dozed through that lesson, here it is again: "Energy may be converted from one form to another, but is not created or destroyed."
Conventional cars are essentially wasteful. Fuel burns in the engine to make the car go. But even the best engines - like the 1.5-litre beneath the Prius's bonnet - turn only about 30 per cent of the heat into mechanical power. The remainder must be discarded. That's why cars have radiators.
Then, when the car is slowed, the brakes turn the car's kinetic energy into heat. Energy, as heat, is being wasted everywhere.
The Prius is so efficient because it cuts waste. The engine is low-revving, low-power but super-efficient. And when the engine isn't needed, it doesn't run. When the Prius slows, the energy that's normally lost as brake heat is captured and stored.
This is the really smart part, the chief reason it's so amazingly fuel-efficient. The electric motor also operates in reverse, as a generator. Put electricity in and the motor spins; spin the motor and get electricity out. When the driver releases the accelerator and applies the brakes in the Prius, the motor switches to regeneration mode. A computer translates the driver's pressure on the pedal into an appropriate mix of regenerative braking and conventional friction braking.
The regenerative braking current is stored in on-board batteries for use later. When the computer decides the stored charge would be useful, the electric motor cuts in.
Despite packing a petrol engine, an electric motor and a generator, the Prius weighs only 50-100 kg more than a similar Corolla.
Most of this is accounted for by the battery pack, which Toyota says is designed to last the life of the car if it's "conditioned" at three-year intervals. Weight savings elsewhere offset these additional components - the Prius doesn't have an alternator or a separate starter motor, for example.
The most elegantly engineered part of the hybrid system is the planetary gearset which mixes and matches engine power, motor power and generator load, all the while acting as the car's transmission. This arrangement is so stunningly simple that it would take about 2,000 words to describe why and how it works.
Every bit as impressive is the software which manages the engine, motor, generator and regenerative braking and maximises fuel efficiency.
That it all works so seamlessly is a triumph. The people who wrote the code for the Prius control software should be working at Microsoft.
Defining moment
Toyota says Prius is Latin for "forerunner". Our dictionary
suggests it means before or formerly.
Electric shockers
GM's EV1: This battery electric two-seater promised to curb that brown LA haze. Poor range between recharges and high lease payments - you could not buy it outright - made the car a failure. Fewer than 1,000 Californians were prepared to pay the price, in both dollars and practicality.
Honda's EV Plus:
A four-seater, it was more practical than EV1. And its nickel-metal hydride cells performed better than the EV1's lead acid batteries. But it, too, flopped after only a few hundred leases had been signed.
Hybrid Version 1.0
If the Prius was software, it would be version 1.0: the hybrid system is well developed, but the body and suspension are quite conventional. So, Toyota officials suggest, there's plenty of scope for improving efficiency through the use of lightweight materials.
Hybrid success
When Toyota launched the Prius in Japan in December last year, it said it would build 1,000 a month if demand was sufficient. Eco-conscious customers rushed to buy it and now the production line turns out double that volume a month. By 2000, Toyota wants to sell 20,000 a year in Europe and the US. Toyota Australia execs are determined we won't be left out.