Downsizing, down-speeding and electric tech to play key parts in Mercedes' powertrain strategy in the next decade
16 October 2014

Mercedes-Benz technical chiefs have revealed an exciting mixture of technologies aimed at meeting short and long-term European CO2 legislation.

More efficient engines, electric vehicles, plug-in hybrids and fuel cells all form part of Mercedes’ development strategy over the next 10 years.

In engine development, the focus is on improved efficiency and performance. Downsizing engine capacity combats friction and the pumping losses caused by the effort of drawing air into the engine. The new V8 engine of the Mercedes-AMG GT and C63 is a classic example of this approach.

The capacity has been reduced from 6.3-litres to 4.0-litres by adding twin-turbocharging to maintain or increase power. Friction-reducing 'Nanoslide' technology has been carried over in the cylinder bores allowing pistons to slide with less resistance. The result is an efficiency improvement of 30 per cent compared to its naturally aspirated predecessor.

New Mercedes-AMG GT tech secrets revealed

Turbocharging can generate high torque at low engine speeds on both petrol and diesel engines, so downspeeding is also on the agenda at Mercedes. If the engine turns more slowly, friction is reduced and so are heat, wear and CO2 emissions. That’s one of the reasons, despite the downsizing regime, Mercedes still favours four-cylinders over three. Engineers argue that a slower-turning four-cylinder gives the same frictional benefits as a three-pot, but is smoother.

“The name of the game is to combine driving fun with efficiency,” says Thomas Weber, group board member responsible for research and car development at Mercedes.

The research chief also believes there’s a crossover between F1 and passenger cars, in terms of learning – if not actual components.

“F1 plays a part with our new hybrid solution. The efficiency we achieve there is huge," he explains. "In the past we were limited to 28-30 per cent efficiency with combustion engines, but with our current hybrid F1 drivetrain we are dealing in the 40 per cent range."

Weber predicts a future where all vehicles will be electrified, but there won't be a 'one size fits all' solution: “Even in lane one, we will see mild hybrids using belt-driven starter-generators or crankshaft integrated starter-generators. In lane two we will have the premium plug-in hybrids and by 2017 we will launch 10 plug-in hybrids. The third lane will be zero-emissions vehicles powered by batteries or fuel cells.

“By 2020, we expect the energy density of battery technology to have doubled and the cost halved,” he continues. “Without any other changes being made, the range of the B-Class Electric Drive could increase to 185 or 250 miles.”

Beyond that, Weber believes there’s more to come with new battery chemistry: “Lithium sulphur will be the next step after lithium ion, followed perhaps by lithium air. Lithium sulphur is comparable to lithium ion but lithium air will be a completely different world.”

With lithium ion batteries, the oxygen needed for the chemical reaction which generates electricity is stored internally. Lithium air batteries ‘borrow’ airborne oxygen from the air and then release it again when the battery is recharged. As a result, they theoretically have a large energy storage capacity – some sources estimate it could be close to that of petrol.

Mercedes-Benz B-class Electric Drive prototype first drive

Looking ahead further still, Weber believes the hydrogen fuel cell is still a strong contender: “With a fuel cell car you can fill up with hydrogen in three minutes but even our fastest chargers take half an hour to charge a battery, so 20 to 30 minutes will probably remain the limit.”

However, Harald Kroger, vice president of electronics and e-drive for Mercedes, thinks the limited range of an electric vehicle is an overstated problem: “These questions often evaporate if you use an EV on a daily basis. A lot of customers realise their regular driving is covered by a 95-mile range.”

Kroger concedes that on-street parking is a problem if drivers are not guaranteed a charging point at work or when shopping but under-street wireless inductive charging is technically possible. Mercedes recently demonstrated a system comprising a pad which can be placed on a driveway or in a garage and plugged into a household wall socket. The rapidly cycling electromagnetic field in the pad induces a current in an electrical coil pack on board the car to generate electricity and charge the battery.

The system is being developed in collaboration with BMW and the same system is capable of charging either brand’s cars. “The cost should be similar to that of an electric door opener,” says Kroger. The system is technically ready but a date for its introduction has yet to be set.

The technology could also make kerbside charging more practical. “My belief is that if electric charging gets into every household owning an electric BMW or Mercedes, then a technical standard could be established. If other manufacturers join that standard it may be possible to put the technology under the road as well, but that’s a little further away," says Kroger.

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16 October 2014

Comments like this must put the anti plug-in Ludite brigade in a right 'tis this morning.
Mercedes, like I, think the range problem of the EV is overstated. It certainly will be when they start knocking on the door of 200 miles plus.
As for "electric vehicles, plug-in hybrids and fuel cells all form part of Mercedes’ development strategy over the next 10 years" it's YES,YES NO. Hydrogen comments are just there to aplease goverments, in 20 years time 50% of the peoplpe 90% of time will get their power from the eletric socket leaving very little market for petrol and even less for Hydrogen.

 

Hydrogen cars just went POP

16 October 2014

"“By 2020, we expect the energy density of battery technology to have doubled and the cost halved,” he continues. “Without any other changes being made, the range of the B-Class Electric Drive could increase to 185 or 250 miles.”"

This target doesn't look too impressive given that Tesla's have a range of 260-300 miles TODAY.
If densities really are likely to double by 2020 then I'd expect Teslas will have a 500-600 mile range!

16 October 2014

And so much more interesting than reading about someone's latest "design language". These efficiency improvements are long overdue - for too long cheap fuel has given manufacturers little incentive to progress. But it's not just the engines that need work, cars need to be much, much lighter if they are to be truly efficient, however they are powered.

289

16 October 2014

...just where is all this extra electricity going to come from?
We are already predicting shortfalls in the near future with practically no electric cars on the road today. We are decommissioning plants with hardly any replacements in the pipeline. Mainly because no one wants one in their back yard.
As an aside, have you seen the price of electricity lately? any one with electric heating will soon tell you, and the bad news is that it is only going up.....quickly.
EDF who are building a new Nuclear power station in the UK have already held the Government to ransom halfway into the build and threatened to stop the construction unless they can be allowed to increase the sale price of electricity by 50%!! yes you heard it right 50%. Where do they think this money will come from...families are already hard pressed and will end up with electricity monthly bill close to their mortgage costs.

16 October 2014

My monthly electric bill is £25, I imagine it will have to go up a considerable amount to match the cost of the average mortgage. Oh and I already run an electric vehicle, albeit just an e-bike.

289

16 October 2014

...this is the problem.
People who don't use much electricity due to having gas or oil central heating have absolutely no idea of the cost of electricity.
My monthly standing order (taking into account the months where heating isn't being used (remember you are going to be using the car every day not 6 months of the year), is £240 p.m. for a small 2up 2 down cottage.
A friend of mine has a 5 bedroom house with an electric underfloor heating system which consumes £600 p.m. in winter!
Charging a car up , even overnight on economy 7 will be similar to charging a storage heater...and remember when you need to re-charge your car during the day, you will be paying peak rate electricity prices...which as I say are set to go up by 50% because of EDF.

16 October 2014

Autocar's last test on the Leaf said costs around £0.025 a mile on the cheapest tariff (I think it was around £3.00 or less to 'fill the tank'). I know exactly how much electricity costs, both day and night. It doesn't matter how much you spend on heating the house the aforementioned is a fact, I suggest you move.

 

Hydrogen cars just went POP

289

16 October 2014

....thanks for your property advice xxxx.
I am sure you wont mind if I ignore your perceived wisdom.

16 October 2014

Here in the UK, petrol and electricity are approximately the same price at around 15 pence per kilowatt hour. Overnight electricity on Economy 7 costs around one third of this and combined with the fact that electric motors are more than 90% efficient (as opposed to around 25% at best for petrol engines) and the economic attraction of an electric car is obvious. Incidentally, while Webber predicts a future whereby all cars are electrified, he didn't say they will all be battery powered. The vast majority will be hybrids of some description, which suggests that the internal combustion engine still has plenty of life left in it.

289

16 October 2014

....actually its running at 16p per KW daytime, and 7.35p per KW Economy 7...so its nearer half price than one third off peak.

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