Volkswagen's Polo BlueGT went on show in Geneva this week running a very interesting turbocharged 1.4-litre four-cylinder engine, the first of a new series of engines which shut down two of the engine's four cylinders under light and medium loads (below 4,000 rpm, and at torque outputs of less than 100 Nm). Does it work? You bet 140 bhp, a top speed of 210 km/h (130 moh) and using the seven-speed DSG tranny, 4.5 liters per 100 km (62.8 mpg) consumption and CO2 emissions of 105 g/km.

The new EA211 series of engines will be used in all future modular transverse matrix (MQB) Volkswagen models. By automatically shutting down the second and third cylinders under light loads, VW claims it can achieve fuel savings of up to 0.4 liters per 100 km in the EU driving cycle. At a constant 50 km/h (30 mph) the savings can be as much as one liter per 100 km, and even at 70 km/h (44 mph) in fifth gear, around 0.7 liters per 100 km can be saved.

Obviously there's a lot of technology involved in a smooth transition from one mode to another to ensure there is no jerk or snatch, and the dashboard keeps the driver informed of how many cylinders are activated.

The Polo BlueGT goes on sale in Europe in July. Plans for other markets have not yet been released.