KIA and its sister brand Hyundai are the latest car makers to take a serious look at manufacturing large scale production hybrid domestic cars.

The Kia Rio Hybrid saloon features a 90bhp 1.4-litre petrol engine, mated to a 12kW, synchronised electric motor and a CVT gearbox.

The high-torque permanent magnet electric motor is mounted between the flywheel and the gearbox and assists' the petrol engine during starting, accelerating and hill-climbing.

During steady cruising the electric motor switches off, while during deceleration it employs regenerative braking' to store energy and re-charge its Ni-MH 144 volt power pack.

The computer-controlled system also allows stop/start motoring, which switches both engine and motor off whenever the car comes to a standstill for more than a few seconds. Restarting is automatic.

The hybrid Rio is the first Kia to employ a CVT (continuously variable transmission).

This type of compact automatic gearbox seamlessly shifts between an infinite range of gear ratios and allows the engine and powertrain to operate at peak efficiency at all times.

With this combination the Rio Hybrid accelerates from zero to 62mph in 12.2 seconds, can reach a top speed of 112mph and returns a fuel consumption of 53.4mpg with a CO2 figure of 126g/km.

Compared to the standard petrol Rio, air pollutants are reduced by 37 per cent and fuel efficiency is improved by 44 per cent.

To help reduce its fuel and power demands, the Kia Rio Hybrid employs special lightweight components - with aluminium bonnet, boot lid and front seat frames - plus lightweight road wheels, low-friction tyres and electric (rather than hydraulic) power steering.

These parts cut the Rio's weight by 220kg, or 23 per cent compared to the conventional steel model.

The Rio Hybrid has been developed at Kia's Eco-Technology Research Centre in Korea, which is equipped with state-of-the-art facilities such as a 700-bar hydrogen filling station, fuel-cell durability test stations, hot/cold test chambers, emissions reduction laboratories and a robotic car dismantling and recycling plant.

l Kia is in the process of supplying the Korean Ministry of the Environment with 3,390 Rio hybrids over the next two years.

The expansion of this hybrid test fleet (from the current 780 cars) makes the Korean operation one of the world's largest future-technology test programmes and it is just one of several Kia research and development undertakings aimed at creating eco-friendly cars for volume production by 2010.

Kia says there are currently no plans to bring the Rio Hybrid to Europe but should the test programme be successful the model could well be with us within just a few years.