First Drive review: Mercedes-Benz C 350 e Sport (2015)

Mercedes-Benz C 350 e Sport, £37,875

To some, Mercedes means comfort, style and luxury. To others, those fans of the tuned AMG versions, it means power, noise and performance. But fuel economy? Eco-friendliness? These are hardly terms the name conjures up. That’s a misconception, says Mercedes, and the C-class plug-in hybrid will help change it. Not only does it boast hypermile efficiency, the car also gives orders on how to drive in the most frugal manner possible.

An in-car “nanny” nags you to take your foot off the accelerator when the vehicle’s radar detects slower traffic ahead by making the pedal pulsate — as if it’s trying to tickle your feet. Thus you can save fuel by avoiding hard braking.

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It pulsates at just at the right moment too, so you coast to the same speed as the vehicle in front without having to brake. Obey and you could cut your fuel bill by 4%, says Mercedes. You can switch off the nanny but you’ll need it if you’re going to stand any chance of achieving the claimed fuel economy of 134.5mpg.

That’s not a misprint and Mercedes insists it’s attainable. In fact the company has so much faith in its technology and the nanny — it calls it a “haptic accelerator” — that it plans to offer 10 different plug-in hybrid models by the end of 2017. Its C-class version is designed to go up against the Audi A3 e-tron, which went on sale last year, and the BMW 3-series plug-in hybrid when it launches towards the end of the year.

In theory these cars offer the best of both worlds: the battery in the Mercedes is said to provide just over 19 miles of range at speeds of up to 80mph. Beyond that, its 2-litre petrol engine will take over.

The C 350 e is managed by a computer that might favour fuel economy, but if you floor the throttle the electric motor and petrol unit combine to produce up to 275bhp, sending the car from 0-62mph in 5.9 seconds.

The software continuously calculates the most economical way for the vehicle to operate, which might mean artificially revving the engine to produce more power than is required on the motorway, and using the excess to charge the battery. Plot your route into the sat nav and the car might save the electric power for a particularly steep hill at the end of your journey, for example.

The dashboard screen can show flowing lines illustrating power being used or recovered — an unrivalled example of driver distraction. It’s the only obvious visual sign that the car you’re in is a hi-tech plug-in hybrid. Its eco-credentials are advertised with a tiny letter e on the boot and the discreet panel for charging that is hidden in the bumper. The interior is as stylish and well finished as a Miami beach club, although boot space is reduced compared with other C-class models — by 30% in the saloon — because of the battery.

Get moving, though, and you realise the heavy penalty that you pay for the hybrid technology: 270kg. It takes the weight of the C 350 e close to a hefty 1.8 tonnes and you can feel it as the car bounces over bumps that you would expect lighter C-class models to glide over. In tighter bends, the tyres squeal.

In a straight line, though, the journey is virtually silent when using electric power alone. Once your 19 miles of battery power are up, the petrol engine kicks in with a buzz, which becomes coarse under acceleration. And it’s at this point where we discover the reality about fuel economy: our test car indicated an average of 36mpg on twisting mountain roads. The claimed 134.5mpg is from an EU test that flatters hybrids.

It’s not something typical users are likely to care too much about, however. This type of vehicle is aimed squarely at company car drivers, who will pay just over £750 a year in company car tax at the higher rate. That’s an annual saving of more than £1,500 on the equivalent diesel. For all the car’s shortcomings, that’s going to be tough to ignore.

If you are tempted, then it’s worth doing soon. The C 350 e is expected to be approved for the plug-in car scheme and be eligible for a £5,000 grant. But the incentive will be reviewed after the general election when the grant for certain vehicles — including this C-class — is likely to be reduced.

2015 Mercedes-Benz C 350 e specifications

• Price: £37,875*
• Engine: 1991cc, 4 cylinders; plus 60kW electric motor
• Power: 275bhp @ 5500rpm
• Torque: 442lb ft @ 1200rpm
• Transmission: 7-speed automatic
• Performance: 0-62mph in 5.9sec
• Top speed: 155mph
• Fuel: 134.5mpg (combined)
• CO2: 48g/km
• Road tax band: A (free)
• Release date: On sale now

Mercedes-Benz C 350 e Sport rivals

Audi A3 e-tron, £34,950

• For Electric-only range of 31 miles
• Against Large battery pack adds 300kg

BMW 3-series plug-in hybrid, £32,000 (estimated)

• For Fun to drive; cheaper than rivals
• Against Not on sale yet

* Prices are before £5,000 government plug-in car incentive, if eligible

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