Stop-start saves fuel and cuts noise

By ALASTAIR SLOANE

French carmaker Citroen claims its new "stop and start" engine technology will reduce fuel consumption in city traffic by around 10 per cent.

The company says a C3 hatchback model it will unveil at the Paris motor show in September will be the first dedicated petrol-engined car in the world to be equipped with the system.

The new technology cuts the 1.3-litre engine in the C3 when the car comes to a halt, like petrol-electric models from Toyota and Honda.

But unlike hybrids, which shut down almost as soon as the car stops, the Citroen engine idles for upwards of 10 seconds before it stops. It then starts up at the touch of the accelerator.

Citroen has not revealed how the technology works and why it delays engine shut-down- wait until the Paris show, it says.

But it says it expects the system to reduce fuel consumption by around 10 per cent in town and city traffic.

"Trials conducted in a large urban environment have demonstrated that in typical customer use, cars are standing still 30 per cent of the time," says Citroen.

"This means that, in addition to improved fuel economy and lower emissions, customers and the urban environment will benefit from cars that are completely quiet when they are not moving."

The Citroen development is the latest in fuel-saving and emissions technology. It comes as carmakers - especially in Japan and the United States - are turning towards petrol-electric vehicles as an interim measure to zero-emission hydrogen fuel cells.

Honda has just unveiled its latest petrol-electric model, the V6 Accord hybrid, in the US. It will go on sale there later this year.

Honda New Zealand would like to get its hands on the car, to complement its hybrid 1.3-litre Civic.

"At the moment, we don't know if it's available to us," said the company's managing director Graeme Seymour. "But we'd certainly take it, if and when it becomes available."

The Accord uses Honda's next-generation hybrid powertrain which develops more power than the present 177kW (240bhp) V6 petrol model.

The Integrated Motor Assist (IMA) system uses a high-output electric motor/generator to capture electrical energy during braking or deceleration and uses that energy to help to power the vehicle.

Toyota uses a different hybrid system in its Prius. But both achieve the same ends: less exhaust emission and more economy.

"Putting hybrid technology into our most popular model is a further indication of Honda's commitment to hybrid technology," said Tom Elliott, executive vice-president of Honda in the US. "We are confident that consumers are ready for more hybrid models.

"The Accord hybrid delivers both increased performance and higher fuel economy. It takes hybrid technology into all new territory."

Honda says the hybrid powertrain offers near-peak torque across the engine's full rev range.

It also shuts down three of the engine's six cylinders at cruising speeds and during deceleration, or when the driver lifts off the accelerator.

"The resulting savings in fuel consumption provide economy comparable to a Civic sedan powered by a four-cylinder engine," says Honda.

The Accord hybrid's exterior has a number of exclusive features including a unique front grille design, new tail-light assembly and special hybrid badging, along with a rear boot lid spoiler and exclusive alloy wheels.