What is it?
The latest diesel hybrid to join the mass market in the UK, and a rather different approach to the technology than we’ve so far seen. The Mercedes-Benz E300 Hybrid gets a 27bhp electric motor (powered by a 19kw lithium ion battery) installed into the guts of the familiar 7G-Tronic automatic transmission, which is then mated to the 201bhp, 2.2-litre turbodiesel motor that is already firmly established and liked in the E250 CDI.
A wet clutch fitted to the 7G-Tronic auto allows the drivetrain to completely disconnect the diesel engine and run on electric power alone, at parking speeds or at higher speeds when under little or no throttle load.
What is it like?
In practice it is an impressive thing. We can’t say that the switch from electric to diesel power is seamless — the inevitable low diesel dirge makes it fairly obvious — but despite this, engine refinement on the move is a real stand-out benefit of the E300. Everything calms to a low thrum or cuts off entirely as the electric motor takes over from the diesel, which happens regularly enough to be genuinely useful in terms of economy even at motorway speeds.
There’s plenty of performance on offer, too, should you want it. With both electric and diesel engine working in unison, you get a strong surge of pace (courtesy of the whopping 435lb ft of torque produced from the combined engines’ efforts) that goes a long way to making the E300 a satisfyingly rapid drive.
However, while the engine is as refined as you would hope, tyre noise is a real intrusion at most speeds on the 16-inch wheels (a no-cost option over standard 17-inch alloys) and Conti PremiumContact2 tyres that we tested the car on.
Handling is decent if not outstanding. You get the familiar wobble and dip of air-sprung suspension, which the E300 has at all four corners, but it does offer some welcome rear-drive precision and response. Still, this does feel like the near two-tonne car that it is. At 110kg over the standard E250 CDI wagon, it’s no surprise that there’s some slightly ponderous body roll dampening attempts at more spirited driving.
Should I buy one?
Well, here’s the problem. At more than £40,000, this is not a cheap executive estate car. The powertrain tech is enjoyable and effective in use, and its low emissions should have particular appeal to business users. If you're one of them then give the E300 serious consideration. It’s a great place in which to cover a lot of miles in comfort with no compromise (but for a slight shortfall in the handling precision), and in return for excellent economy, a great BIK rating and a warm glow to your eco-conscience.
It’s a trickier prospect for private buyers. The better economy you’re likely to see from the E300 over non-hybrid equivalents seems a small benefit to justify the substantial premium it commands over conventional rivals.
Mercedes E300 BlueTEC Hybrid estate
Price £41,435; Top speed 144mph; 0-62mph 7.8sec; Economy 62.8mpg; Co2 116g/km; Kerbweight 1955kg;
Engine type 2143cc turbodiesel, 4 cyls, plus electric motor;
Power 201bhp at 4200rpm;
Torque 435lb ft at 1600-1800rpm (combined);
Gearbox 7-spd wet clutch auto