10 Series Prius

THE world’s first production hybrid vehicle was the 10 Series Prius, a small four-door sedan with a petrol/electric combination powerplant.

The original was launched at the Tokyo Motor Show in October 1997, to an astonished world.

Global exports of a thoroughly facelifted model commenced from 2000, with Australia following America with the Prius in October 2001.

"Hybrid" means the Prius combines petrol and electric power for motivation, producing a significant cut in both fuel consumption and pollutants compared to a traditional petrol engine.

Interestingly, the Toyota was actually the second hybrid to go on sale in Australia, following Honda's Insight coupe that appeared here in very small numbers from April 2001 to June 2004.

The Prius differs in the design of its hybrid system because the petrol engine doesn't run at light throttle openings, while the Insight uses a small electric engine to supplement the power of its 1.0-litre petrol engine.

But while the Honda sold less than 40 of the two-seater Insights in this country, the Toyota had a huge advantage because it was a full five-seat sedan of basically the same dimensions as a Corolla.

At the heart of the Prius is the Toyota Hybrid System (THS) driveline that consists of a purpose-developed 1.5-litre four-cylinder engine, a continuously variable transmission (CVT) which also functions as a power-split device, a generator, an electric motor and reduction gears to the front axle.

The 33kW electric motor handles light-throttle driving, with the 53kW variable valve timing (VVT-i) engine chiming in as speeds rise. The electric motor churns out a massive 350 Newton-metres from 0 to 400rpm, while the petrol engine contributes its maximum 115Nm at 4200rpm.

This translates into leisurely acceleration, with a 0-100km/h figure of 13.4 seconds claimed, but the fuel consumption figures are much more impressive: 4.6 litres per 100km on the city cycle and a miserly 4.2 L/100km on the highway cycle.

Toyota claims that in city driving emissions of carbon dioxide - which is the primary greenhouse gas emitted from vehicles - are approximately half those of a similarly-sized vehicle, while emissions of hydrocarbons, carbon monoxide and nitrous oxide are cut by 80 per cent.

Cleverly, energy that is not required to propel Prius is converted to electricity and stored in a sealed 274 Volt battery for later use, and kinetic energy generated by the braking system is also converted into electricity and stored.

No less than 12 computers make Prius work, controlling the drive system including transmission, battery, inverters, cooling systems, steering, ABS brakes and dual airbags.

All cars include climate control air-conditioning, remote central locking, power windows and mirrors, six-disc CD audio system, alloy wheels, ABS with electronic brake-force distribution, driver and front passenger airbags and lap-sash seatbelts all-round.

The only option is DVD-based satellite navigation.