In theory, a 2.0-litre diesel with only mild-hybrid assistance sounds like an outdated powertrain for a large executive saloon. BMW UK must think so: the 520d and 530d are no longer sold here.
However, it doesn’t take many miles in the E220d to be reminded that, away from the tax benefits of EVs and PHEVs, diesel really suits a car like this.
I’m a big fan of standard cruise control but don’t much like adaptive cruise, except Mercedes’ Distronic, which seems to read my mind. It’s easily the best system I’ve tried.
Illya VerpraetRoad Tester
You can just about hear that this is a diesel engine, but at no point is it unrefined or raucous. Whether on a cold start, while pootling through town or being run to the limiter during performance testing, this ‘OM654M’ unit quietly does its work, seemingly far away in the engine bay. Unlike some mild hybrids, you can easily disable the start-stop system, but we rarely felt the need, so quick and smooth is it to shut down and start back up.
Despite registering a planetary 1917kg on the weighbridge, and the test track being both damp and very cold, the E220d powered to 60mph in 7.2sec, which is 0.2sec quicker than the outgoing 520d. Next to many EV or hybrid options it’s nothing special (the Audi A6 50 TFSIe did it in 5.7sec), but the effortlessness impresses – and is what really counts.
First of all, it always delivers the same performance and doesn’t depend on having enough charge in the battery, like a PHEV. The engine also works well with the nine-speed automatic transmission – most of the time. The gearbox doesn’t annoy by lugging the engine like so many others, and it is quick to shift down a gear or two to make the most of the engine’s rich torque but without sending it to the redline.
Yet the gearbox is also our main target of criticism. Mostly it’s smooth, but it can be caught napping when you ask for something it wasn’t expecting. If you suddenly accelerate when you had been slowing (because the lights turned to green after all, for instance), or accelerate hard from a stop at a busy junction, the gearbox can need a moment to shift down or engage drive.
We've not performance tested an E300e plug-in hybrid, but it feels as quick as its official 6.4sec 0-62mph time suggests. More impressive is how the engine and electric motor work together. While some PHEVs don't feel like they're making all the power they're supposed to unless you've got your foot to the floor, that's not the case here. The electric motor subtly boosts the petrol engine to give efforless thrust without sending the revs soaring. The gauge cluster shows quite clearly how much throttle you can use before the engine will be forced to kick in. The petrol engine itself is smooth and free-revving. With 127bhp of electric power, the E300e is not exactly a rapid EV, but feels swifter than that figure suggests. It's possible to safely get up to motorway speed and stay there. While in electric mode, the shift paddles function to change the level of regenerative braking.
The software keeps a decent amount of charge in reserve, so that even when the battery is too empty for EV mode, the E300e still functions as a decent full hybrid, managing to keep the engine switched off remarkably often. Sport mode will actively recharge the battery from the engine, which is inefficient but does ensure that performance isn't noticeably degraded.
All E-Classes come with shift paddles but no obvious way to engage manual mode – it’s done via an on-screen menu. It’s not ideal, but the menu is easy to find, and a diesel executive saloon isn’t the kind to invite manual shifting.
The braking figures probably say more about how much performance summer tyres struggle in damp, near-freezing conditions than it does about the E-Class’s stopping ability: 56.2m from 70mph is long for a car like this. Interestingly, it was about four metres longer still after disabling the ESP, which is clearly doing quite a lot to stabilise the car under braking, as well as under acceleration.
Pedal feel – a big weakness with electrified Mercedes – was fine in normal use but felt soft during the emergency stop.
