Volvo’s has become the latest automaker to combine fuel saving start/stop technology, which reduces emissions of CO2 by up to 8%, with an automatic transmission – its six-speed ‘Geartronic’ transmission.

The technology is fast catching up with autos – it is also available with the new torque converter CVT ‘box on Toyota’s new French-built Yaris.

Volvo has launched four new models with automatic and start/stop, initially using the two-litre, I5, D3 turbo diesel launched in 2010, cutting CO2 emissions by 10g/km and reducing fuel consumption by up to 3.6 miles per gallon.

To begin with, this new technology is available as standard in the four of Volvo’s models, the all-new S60 and V60, V70 and S80.  All four models are available to order now and attract no price increase for this added technology and beneficial decrease in CO2 and fuel consumption.

Prices are unchanged.

“Continuously reducing CO2 emissions from conventional powertrains is an important part of our DRIVe Towards Zero emission strategy. It is the most effective way to cut CO2 throughout our model range in the short term. This work is running parallel with our innovative focus on electrification technologies,” said R&D chief Peter Mertens.

Combining start/stop with automatic gearbox is a larger technology challenge than the manual start/stop version. Without a signal from the clutch pedal as used in manual transmissions with start/stop, the engine must restart instantly when the driver moves his or her right foot from the brake pedal to the accelerator.

“We have focused on achieving the same response as you get with today’s conventional automatic gearbox. The action is so seamless that it feels like the car starts accelerating immediately when the engine restarts,” added Mertens.

The technology uses brake pressure measurement to trigger when to stop and start the engine. The start/stop system is programmed to shut down the engine immediately when the car reaches a standstill (0 mph).

An electric pump keeps oil pressure up in the automatic gearbox while the engine is stopped. The system also includes an upgraded starter motor to cope with the increased number of starts.