ONE day, your grandchildren will learn about the Toyota Prius in their schoolbooks. They will read that not only was the Prius the first hybrid vehicle to be offered to the South African public, it was also the first one to be mass-produced in the world. Today, it represents a confident step into a future of cleaner, more efficient, but still practical transport.
However, it enters the South African market at a time when most people do not know what a hybrid car is, let alone its advantages. And, secondly, you cannot buy a Toyota Prius. It is available only on a fouryear lease. When the lease period is over, you hand the car back to Toyota. Consequently, Toyota faces two enormous challenges with the Prius; a) educating the public about hybrid vehicles in general, and b) convincing them to put their money into something they don’t get to keep…
The Prius is a petrol-electric hybrid. This means that it is driven by both a petrol engine and an electric motor, feeding off a nickel-metal hydride battery. These two power sources are controlled by what Toyota calls Hybrid Synergy Drive. HSD switches seamlessly between the engine and motor depending on the driving circumstances and, when needed, combines the two for maximum power.
The engine is a 1,5-litre, four-cylinder unit that produces 57 kW at 5 000 r/min and 115 N.m of torque at 4 000. It is an Atkinson-cycle engine, which means it is designed to provide maximum efficiency at the expense of some power. This is done by reducing the effective compression ratio: the intake valve is kept open longer so that a small amount of reverse flow is allowed into the intake manifold.
The electric motor produces an additional 50 kW between 1 200 and 1 540 r/min, and strong torque of 400 N.m from virtually zero to 1 200 r/min. When the driver of the Prius accelerates hard (going uphill, for example), the petrol engine and electric motor combine to produce an overall output of 82 kW and 478 N.m of torque. Power is sent to the front wheels via a computer-controlled continuously variable transmission.
The electric motor draws its power from a nickel-metal hydride battery. Toyota says it will last for the entire life cycle (about 10 years) of the vehicle, and requires no maintenance. Because it is charged via regenerative braking, and by the engine, it never needs to be plugged in.
That, then, is essentially the heart of this green beast. But the Prius pushes the boundaries in several other ways, too. It is the first car to use only an electronic circuit to coordinate the power steering, braking, traction and vehicle stability control systems. This drive-by-wire system is lighter and more responsive than conventional systems because it has no mechanical or hydraulic links. For example, when the driver swerves or brakes hard to avoid an accident, the vehicle movement control system instantly decides which balance of ABS, EBD, TRC and VSC is needed. The Prius’ electrically controlled braking system provides hydraulic brake control independently and in linear fashion to all four wheels. We can certainly vouch for the system working under emergency braking, because the Prius stopped in an average of 2,74 seconds during our test sequence (10 stops, 100 km/h to zero) – a time usually reserved for sports cars with massive brakes!
Another nifty feature is the EV drive mode, which allows the Prius to be driven on electric power only for short distances and up to 50 km/h. Because the car is almost eerily silent in this mode, it is ideal for sneaking into the garage late at night.
Toyota has backed up the radical mechanicals with an equally way-out styling job… inside and out! There is simply nothing on the road that looks like the Prius. Essentially, it is a large five-door hatchback, but the lines have a bit of coupé and MPV in them as well. It is a very aerodynamic shape, which also aids in lowering the fuel consumption.
The cabin would not look out of place in a science-fiction movie, because everything is different. The steering wheel isn’t round, but elliptical to ease ingress. Once seated, you’ll notice the instrumentation (comprising digital speedo, fuel guage and warning lights) is mounted in a strip at the base of the windscreen.
However, the main focus of the facia is the seven-inch, full-colour, touch-screen display in the middle. This gives access to the audio and ventilation system controls and can also show – via a moving graphic – how the car is utilising its power sources. This is a bit gimmicky, but still strangely addictive.
Since there is no hangdown section, or a traditional gearlever or handbrake, a lot of space is freed up for the front occupants. Toyota has used this advantage to create many storage spaces; dual cubby, large lidded box between seats, drinkholders etc. The sensation of vast space carries through to the back of the cabin, where passengers have Camry-rivalling rear legroom. At 244 dm3 the boot may not be very big, but by folding the 60:40 split rear seats it can be expanded to a more useful 1 104 dm3.
Unfortunately, the Prius did not quite live up in terms of Toyota’s traditional build quality, and we noticed a few creaks and small rattles on rougher roads. Also, the facia plastics show scratch marks easily.
The Prius has all the creature comforts you’ll need; electronic climate control, JBL six-disc CD loader, electric windows and mirrors, heightadjustable driver’s seat, cruise control, transponder key immobiliser etc. The safety package is even more comprehensive, and includes dual stage front airbags, curtain side airbags for front and rear passengers, and side airbags for the front occupants. There are fuel and electric circuit cut-off systems that deploy in the event of a crash, and the front seatbelts have force limiters and pre-tensioners. The Prius is currently the only hybrid vehicle with a five-star EuroNCAP safety rating.
So, after reading about all the science fiction stuff, what is the Prius like to drive? Pulling off is certainly interesting, because it happens with no noise. You slot the keycard into its hole, hit the power button, select reverse or Drive, de-activate the foot brake and voila!, you’re off in a hush. Accelerate harder and the petrol engine joins in seamlessly, and engine noise compares with that of a normal car, except that because of the continuously variable transmission, it is a constant drone, similar, according to one tester, to a Harvard aeroplane... It is annoying.
The electrically assisted steering is very light, and the feel artificial, but at least it is fairly sharp. You quickly get the message that this is not a car designed with handling finesse in mind. There is also a strong tendency to understeer, and the Prius is not very stable in cross winds. But all this will matter little to the people who want a Prius. For them, it is more important to know that the ride quality is very good, without becoming wallowy.
It is also quite a bit faster than you may expect. We couldn’t match Toyota’s claimed 0-100 km/h time of 10,9 seconds, but our 12,35 sec time is good enough, and so is the 171 km/h top speed.
The main reason you might be interested in this car will be its fuel consumption. The Prius is at its most efficient in stop-go traffic driving, because it is in these conditions that the electric motor is most often utilised. Also bear in mind that the petrol engine switches off as soon as the car comes to a stop.
In everyday driving conditions (which includes traffic and normal driving), our fuel index figure came to an excellent 5,3 litres/100 km. This makes it the most economical car on the market, but not by as big a margin as you may think. The Citroën C3 HDI has an index figure of 5,5 litres/100 km.
If you’re a person that does a lot of relatively high speed cruising, the Prius’ consumption figure is likely to rise to just over 6 litres/100 km.
The most impressive thing about the Prius is probably how quickly it becomes “normal” to live with. By driving this car you are doing your bit to save the planet, but at the same time not having to make any major sacrifices. It is comfortable, fast enough, frugal, nice to drive and, to some, even good looking. We also completely understand the reasoning behind launching it in South Africa so early. But our readers must make their sums carefully because, as we see it, there is little tangible benefit in opting for a Prius at this stage. You’ll save fuel, most certainly, but then you’ll also not have anything to trade in or resell after four years… You may reason that the point of the Prius is also its low emissions and be correct, but in South Africa you are not being rewarded with lower taxes (as in the UK) for driving a low emission car. So, the Prius is destined to appeal to those who have the financial reserves to own several other cars, and drive the hybrid to make a statement...
Original article from Car