The Financial Times reviews the Mercedes S-Class S 400:
A first glance under the bonnet of the S 400 will leave you wondering what all the fuss is about. It looks a perfectly ordinary engine bay, with a 3.5 litre V6 petrol engine in the usual place and the battery roughly where you would expect to find it, tucked away in a corner. Except that, out of sight inside the engine and transmission casing, a powerful electric motor surrounds the crankshaft. And, despite being roughly the same size and shape as a conventional car battery, this one is vastly more powerful and is the heart of the world’s first fully commercialised hybrid car to use lithium-ion battery technology. That gives the Mercedes an advantage over the Lexus: the latter has a much larger and heavier nickel metal hydride battery pack, which takes a big bite out of the boot space. Like the Lexus and Toyota’s Prius, the S 400 is a “parallel” hybrid. At low speeds around town it can be driven on the zero-emissions battery pack alone. On the open road it can cruise on its 279hp petrol engine, or, for higher speeds and overtaking, both petrol and 20hp electric motors can work together. Deciding which to use and when requires nothing of the driver – it’s all computerised. That 20hp might not sound much and it isn’t. What matters is the electrical unit’s torque: nearly 120lbs ft from standstill, almost half as much as the torque of the petrol engine. This makes take-off very lively, although nowhere near as lively as the autobahn-storming Lexus 600h – but then the Japanese maker has opted for a hugely powerful 439hp petrol engine. – from FT