The smaller four-cylinder engines in the latest Mercedes-Benz E-Class are already imbued with the company's latest efficiency-enhancing technologies and now it's the turn of real culprits in the fuel guzzling stakes - the bigger petrol engines.
Just announced in Germany, the new V6 and V8 petrol engines sip up to 20 percent less fuel than their predecessors thanks to technologies like direct fuel injection and an idle stop system - which is also now standard on the four-pot engines.
The new naturally aspirated 3.5-litre V6 motor in the E350 BlueEfficiency is good for 225kW and 370Nm (up from 215kW and 365Nm), while NEDC official consumption has been reduced from 8.5 litres per 100km to between 6.8 and 7.0 l/100km. CO2 emissions are down 20 percent to 159-164g/km.
Similar gains have been made by the new 4633cc V8 engine that replaces the previous 5.5-litre unit.
It may be smaller, but it's now twin-turbocharged, outputs rising to 300kW and 600Nm, up from 285kW and 530Nm. NEDC fuel consumption, meanwhile, drops from 10.8 to 8.9 l/100km, with CO2 emissions rated at 209g/km.
Other features on the new V6 and V8 petrol motors include a Multi-Spark Ignition system that enables up to four sparks to be triggered in rapid succession within one millisecond and latest generation Piezo injectors that allow up to five injections per power stroke.
Furthermore, both engines boast aluminium crankcases, pistons and cylinder heads, while the engine's lightweight design and intensive fine-tuning of details has resulted in a 28 percent reduction in engine friction.
Further aiding efficiency, all self-shifting E-Class models are equipped with the improved 7G-Tronic Plus seven-speed automatic transmission.