The Mercedes-Benz E 350 e plug-in hybrid offers the promise of 134.5mpg and zero emission capability in an executive saloon with the Mercedes badge.
Model/Engine size: Mercedes-Benz E 350 e AMG LINE Saloon
Fuel: Petrol-electric plug-in hybrid
Fuel economy combined: 134.5 mpg
Green Car Guide rating: 7/10
By Paul Clarke
Things really have moved on in recent times. Even just five years ago, few people would have believed you if you’d have said that your Mercedes E-Class returns 134.5mpg. However this is the official economy figure of the Mercedes-Benz E 350 e. Did we get come close to achieving this in real-life driving? Read on to find out.
The Mercedes-Benz E 350 e has a 4-cylinder, 2-litre petrol engine combined with an electric motor powered by a lithium-ion battery, with drive transmitted to the rear wheels via a 9 speed 9G-Tronic Plus automatic transmission. As opposed to the previous E-Class Hybrid, this latest version is a plug-in hybrid, giving an all-electric range that you can count in miles rather than yards.
The styling is in keeping with Mercedes’ latest design language – in other words it’s increasingly curvy compared to recent models.
The interior is a typically shiny Mercedes affair, with a large, wide (12.3-inch) (optional) central touchscreen. Design is something that is subjective; what you can’t argue with is that many motorists appear to like the current styling approach of Mercedes, as sales are on an upward trend.
The boot capacity is slightly reduced due to the hybrid’s battery, which sits under the boot floor.
A key feature of the Mercedes E-Class has always been a comfortable ride, and even with the added weight of the plug-in hybrid system (taking the car to 1,925 kg), this remains one of the strong points of the latest E-Class. Presumably in the face of competition from BMW, there has been increasing pressure on Mercedes to improve the handling of the E-Class, and this latest model is certainly the best yet in terms of ride/handling balance.
The other quality expected in an E-Class is the ability to offer a hushed and comfortable motorway cruising ability, and again, the latest E-Class scores well in this area, although the large wheels and tyres do translate some noise from poor surfaces.
There are a range of drive modes to choose from: Comfort, ECO, Sport, Sport +, and Individual. You can also select the hybrid drive mode, with the ability to choose between Hybrid, E-mode, E-save, or Charge – although on right-hand drive cars the switch for these settings is hidden behind the infomedia rotary dial so it’s difficult to see. To access some hybrid drive settings, you need to change the drive mode first.
As is usually the case with Mercedes models, the gear selector is on the right-hand side of the steering column, rather than between the front seats. On the left-hand side of the steering column is the stalk for the indicators and windscreen wipers, below that is the stalk for the cruise control, and next to that is the stalk to adjust the steering column. And there are also the paddles to change gear on either side of the steering column. That’s quite a lot of controls in a small area.
The handbrake is also in an unconventional area compared to most cars, although it’s conventional for Mercedes, being positioned low down, under the light switch, on the right-hand side of the dashboard.
So aside from ride and handling, which we’ve already covered, how does the E 350 e drive? On the motorway – a key environment for the E-Class – life is good. However in normal driving the 2-litre petrol engine can sound strained under acceleration. Although the concept of the car is for it to offer ‘sporty performance’ due to the combination of petrol engine and electric motor, in reality the car doesn’t feel that fast, with initial pick-up, as well as responses through the rev range, often being somewhat tardy. And there are also times when it doesn’t feel as smooth as you might expect during transitions between the two powertrains. Overall it doesn’t feel seamlessly integrated or a particularly direct driving experience.
There’s a multitude of safety systems including lane departure warning, which intervenes if you drive too close to white lines; you can switch off this particular feature if it’s not to your liking.
The satnav isn’t quite as quick or intuitive to enter details as some rivals – a lot of button pressing is needed – and it doesn’t show delays as effectively as some other systems.
The official combined NEDC economy figure for the Mercedes-Benz E 350 e is 134.5mpg – equating to 49g/km CO2, or 57g/km for our AMG LINE test car. As regular Green Car Guide visitors will be aware, this is a pretty much useless figure, as real-life economy will completely depend on the distances driven between charging.
On that note… the official all-electric range of the E 350 e is 30km, or 18.6 miles. This is less than rivals, but there’s more news: we carried out three tests of the all-electric range in real life driving (in the environment in which electric propulsion should be used, ie. urban driving), and we managed 9, 11 and 12 miles of electric driving. This is disappointing for a plug-in hybrid, especially one that costs around £50,000.
So what economy figure did we get in real-life driving? After a week of mixed driving, but around 80% on motorways at around 70mph, we averaged 43.8mpg. This is predictably well short of the official 134.5mpg, but not actually too bad for a large and heavy petrol E-Class. Apart from the hybrid system, the aerodynamics should help with the fuel economy; the drag coefficient (Cd value) of 0.23 is excellent.
Although the real-life all-electric driving range wasn’t that impressive, what was useful was the ability of the car to run on purely electric power on motorway journeys, such as when coasting. The instrument cluster provides data on the amount of time that the petrol engine is switched off during your driving, some examples are as follows:
You would hope that this ability for all-electric running has to make the E 350 e more efficient than a standard petrol E-Class.
The Mercedes-Benz E 350 e AMG LINE Saloon costs £47,720. Our test car had options of the Driving Assistance Plus Package (£1,695), the Premium Plus Package (£3,895), the 12.3 inch Cockpit Display (£495) and Metallic Paint (£645), bringing the total to £54,450.
The E 350 e is available in SE or AMG LINE spec. It’s important to note that the CO2 and therefore the BIK figures are different depending on which spec you opt for. The SE has a CO2 figure of 49 g/km but this rises to 57 g/km for our AMG LINE test car, primarily due to its large 19-inch alloys, and the BIK rate of 9% for the SE increases to 13% for the AMG LINE.
A Mercedes E-Class with a benefit in kind figure of just 9% will appeal to company car buyers. However they should be aware that the official economy figure of 134.5 mpg is likely to translate to a figure similar to our 44mpg in real-life driving.
But the main conclusion about this car is that the Mercedes-Benz E 350 e has the extra technology, weight (all 1,925 kg of it) and cost of the plug-in hybrid system, but it only delivered between 9 and 12 miles of all-electric range in real-life driving. In our view, it’s not worth all the extra technology, weight and cost to result in such a short all-electric range.
Due to concerns over CO2 and air quality, legislators want the entire automotive world to move from petrol and diesel powertrains to electric. For over 10 years Green Car Guide has championed efficient cars, so you would imagine that we would come out in favour of the plug-in E-Class over the diesel E-Class. So do we? Read the review of the Mercedes E-Class diesel and find out. In the meantime the Mercedes-Benz E 350 e gains a Green Car Guide rating of 7 out of 10.
Fuel economy extra urban: N/A mpg
Fuel economy urban: N/A mpg
Test economy: 43.8 mpg
CO2 emissions: 49 g/km (SE); 57 g/km for AMG LINE test car
Electric driving range: 18.6 miles
Green rating: VED band A
Weight: 1925 kg
Company car tax liability (2017/18): 9% (SE); 13% for AMG LINE test car
Insurance group: 40E
Power: 211 hp (engine) 286 hp (system)
Max speed: 155 mph
0-60mph: 6.2 seconds
Torque: 550 Nm (350 Nm (engine) plus 440 Nm (electric motor))