SUV-loving USA sees Benz hybrid first

Mercedes-Benz's ML450 hybrid has pipped BMW's X6 ActiveHybrid in the race to sale in the USA.

Built in the US, both cars reach showrooms within a couple of weeks of each other. The catch for Benz buyers is that they can't buy one.

Until the company sorts out the supply of batteries to its satisfaction, the car remains a lease proposition only -- 36 months at $659 or 60 months at $549.

Reflecting the desperation in the air to get fuel-efficient, low-emission vehicles to market in double quick time no matter who wins line honours, the two vehicles share a fair amount of the hybrid technology in their drivetrains. It's the result of a joint development deal between Daimler, BMW, GM and Chrysler.

The system combines two electric motors with a petrol engine. The first, sitting on the transmission output shaft, is configured to get the vehicle moving from stop.

The second is aimed to cut in give the burner a midrange acceleration boost with minimal cost in fuel -- kickdown is a particularly effective way to empty the fuel tank for a standalone burner.

The sharing stops at the internal combustion engine, however. Which is where BMW's troubles might start. Influential online commentator Edmunds reflected wider sentiment in its headlined about the hybrid X6 release thus: "BMW Prices 18-MPG, 5688-Pound ActiveHybrid X6 Crossover Starting at $89,725". Read: it's thirsty, it's obese, it's expensive -- so what's the point?

Where BMW has gone down the questionable sporting path by hitching the hybrid element up to its twin-turbo 4.4 litre V8, Benz has taken a humbler approach with an Atkinson cycle 3.5 litre V6.

In cohorts with the electric motors, it producing 250kW and puts a respectable 516Nm of torque to tar.

Fuel consumption averages out at 10.5L/100km combined cycle. The BMW, by comparison, averages just over 13L/100km combined.

Read the latest Carsales Network news and reviews on your mobile, iPhone or PDA at www.carsales.mobi