Car manufacturers are turning to innovative solutions to meet stringent new CO2 limits; here's a British project that might have found the answer
13 September 2016

If making cars that return solid profits wasn’t difficult enough already for many European car makers, things are about to get a lot worse.

Thanks to an unholy combination of onerous EU fuel economy legislation, new economy tests and the backlash against diesel pollution, the cost of making vehicles could be set to spike by the end of the decade.

The primary hurdle is the looming European Union fleet average CO2 legislation. Due in 2020-2021, it’s been set at just 95g/km – a 60% reduction on the 2007 baseline. The figure equates to 69mpg for a petrol car and 78mpg for a diesel.

Car makers that build bigger and heavier vehicles will still have to reduce average consumption by the same 60%, but the EU acknowledges that these mainly premium brands are starting from a higher baseline.

According to the International Council for Clean Transport, this means Mercedes-Benz will probably have to hit a fleet average target of around 101g/km of CO2 in 2021. Ford is expected to have a fleet average target of 92g/km and Renault-Nissan 93g/km, while Fiat-Chrysler is expected to have a fleet average target of just 89g/km.

Our Verdict

Ford Focus

Britain's biggest-selling family hatchback gets a mid-life refresh, but can the Ford Focus hold off the likes of the Volkswagen Golf and the Seat Leon?

Find an Autocar car review

Driven this week

Until the end of last year, most car makers expected to use a combination of diesel engines, stop/start technology and further gains in aerodynamics and weight saving in order to massage down average fuel consumption to meet these EU laws.

But the Volkswagen emissions scandal blew these assumptions wide open. Many European car makers are now questioning whether diesel engines will survive in less expensive vehicles with the likelihood that new real-world emissions tests will be both difficult and expensive to meet. It’s not too fanciful to suggest that by the end of the decade, any car with a retail price under around £23,000 (the majority of new cars sold in Europe) is unlikely to be fitted with a diesel engine.

So, with the EU CO2 targets very close (at least in terms of automotive timescales) and diesel looking set to become a more premium-priced powertrain, where does this leave the European car industry?

Not without hope, because mild hybrid technology – a less expensive form of drivetrain electrification than that seen in classic hybrids such as the Toyota Prius – is maturing just in time. And much of this technology is being pioneered by UK-based engineering consultancies.

Shoreham-based Ricardo’s Advanced Diesel Electric Powertrain (ADEPT) project is just one example. It takes one of Ford’s most frugal models – the 1.5-litre diesel Focus – and adds a 48V electrical system, a turbocharger, a super-fast stop-start generator and a low-cost but high-tech battery pack.

The ADEPT project is a collaboration with a host of tech companies that has been under development for three years and is being shown off at this week’s Low Carbon Vehicle event at Millbrook.

Ricardo says the production version of the 1.5 TDCi Focus is already homologated at 88g/km of CO2. While that’s below Ford’s 2021 average CO2 target across its model portfolio, it needs to be even lower in order to allow the company to sell more of its bigger and more profitable models, such as the Kuga, Edge and S-Max. The ADEPT concept drives that 88g/km figure down to around 78g/km – but, as we’ll see, it comes at price.

Ricardo’s mild hybrid adaptation of the Focus is extensive. Out goes the 12V alternator, the mechanical air-con compressor and mechanical water pump. In their place comes a 48V integrated starter generator (ISG), which acts as a super-fast starter motor and charger and can also assist the engine at low speeds.

ISG also provides the power for a 48V air-con compressor and a 48V water pump. A DC/DC converter is used to power the rest of the Focus’s 12V electrical systems.

The 48V battery pack is a lead-carbon unit rather than the more conventional (and expensive) lithium ion unit. This battery tech is still in development but is said to be much more tolerant of extremes of temperatures than lithium ion.

Developed by UK company CPT, the ISG is said to be up to 80% more efficient than a conventional alternator and is designed to run in two directions – one to act as a charger and one to help drive the engine. Ricardo says it can “assist the engine” by adding 7.5kW (via the drive belt to the crankshaft pulley) to the engine’s output, and when it’s being used to slow the car via the engine, it can recharge “up to 12.5We” into the 48V battery.

Ricardo’s own figures show a monumental torque curve, peaking at around 221lb ft at just 1500rpm, with 110lb ft already on tap at just 750rpm. The standard 1.5 TDCi engine produces 199lb ft at 1750rpm.

The electric water pump is also an important link in the engineering chain. When cold, an engine’s fuel consumption is much higher, because cold oil means high levels of friction. A switchable electric pump – rather than a continuously driven mechanical pump – means coolant isn’t pumped around until the engine has reached operating temperature.

The most remarkable idea on Ricardo’s prototype is probably the Turbogenerator Integrated Gas Energy Recovery System (TIGERS) ‘e-turbine’, which sits in the exhaust stream and uses exhaust gas to drive a generator. Ricardo calculates that at motorway speeds, Tigers could recover around 1.4kW of energy to the battery. 

So what’s it like on the road? Unusual, to say the least. One of the main philosophies behind the ADEPT Focus is ‘down-speeding’. Ricardo says running the engine at a lower speed – through longer gearing – reduces fuel consumption. Normally that would mean reduced acceleration, but ADEPT uses harvested waste energy to drive the electrically powered turbocharger, which then boosts performance.

On the roads around Shoreham, the ADEPT Focus felt somewhat slow and unresponsive, although much of that sensation was almost certainly due to the fact that the car was demanding I upshifted at lower engine speeds than seemed natural. After a while I became convinced that some form of automatic transmission would have been better suited to this drivetrain, because it would surely shift more quickly and at the optimum time.

Even so, in town driving it was fine, having enough low-speed acceleration to find gaps. It was on the wide open roads and long uphill drags that the ADEPT concept seemed to lack the traditional driveability drivers take for granted. Of course, the whole point of the concept is to reduce fuel use, so we can’t expect this car of the near future to offer breezy performance.

But that is the essence of ADEPT. It trades that breeziness of progress for something more regulated and controlled. In its current form, I don’t think many drivers – even those with no interest in motoring – will like it much, but how else is the car industry going to get the average Focus-class car to return 78g/km of CO2?

Then there’s the cost of the technology. Ricardo’s calculations suggest it will probably cost €80 (roughly £67) in engineering content for each 1g/km reduction of CO2. That it could add at least €800 (£674) to the factory cost of a future Focus-sized car is sobering – and not just for hard-pressed car makers.

And while you’re chewing this prospect over, the European Union is currently ‘consulting’ on what the fleet average CO2 levels should be for 2025. One thing is for certain: they’ll be even lower. 

Join the debate


13 September 2016
That's what this sounds like.Having weened the sheep-like masses on to SUVs the industry might also now consider weening them off, which would be another way to cut emissions in an overcrowded world although they will struggle to keep margins high without them.


13 September 2016
.....Produce lower Co2 in small cars allows more wriggle room for AMGs and Bentleys? I think all of this could work but I was surprised that even with the higher gearing it yielded only -10g/km of co2. I wonder if they could model a sweet spot with different batteries that yield better results.

As per previous I suppose this is the law of diminishing returns. I winder the effect of weight would -200kgs be also lower Co2 by the same amount? If so I suppose the engineering cost per reduction in Co2g/Km is higher...

13 September 2016
Given that Honda had pretty much perfected the mild hybrid nearly 20 years ago, I am surprised it has taken this long for other makers to adopt it for large scale production. True the original Honda Insight didn't have thermal energy recovery or turbocharger, but it's integrated starter generator (Honda called it Integrated Motor Assist) sounds pretty similar to the 48 volt system being developed by Ricardo. A mild hybrid system offers a relatively simple way of improving efficiency without significant weight penalty since the addition of batteries and motor is offset by not having a conventional starter and alternator - and theoretically at least the brakes could be smaller and lighter because of energy absorbtion during braking. To my mind it's a no brainer, but it's taken legislation to get things moving...

13 September 2016
The car market is broken. Chronic over supply means that manufacturers are addicted to pumping ever more new metal onto the roads - meanwhile, poorly maintained 5 year old diesels pump ruinous amounts of pollution and CO2 into the atmosphere. When people point out (rightly) that our use of resources is unsustainable, this is what they mean. The EU could and should have taken radical steps years ago, and encouraged car manufacturers to find a new business model - one that includes proper aftercare and upgrades for older cars.

13 September 2016
I think the commenters here have hit the nail on the head and it's interesting to see how they reverse the doom and gloom theme of the article. Take off your car industry blinkers Autocar and get a little more consumer-savvy!

Far from being draconian, the EU legislation sounds good to me - humans need air that's fit to breathe. And if the economics creates demand for (British) engineering ingenuity, then great!

One thought - why not apply the (costly/bulky/heavy) mild hybrid treatment to the bigger, thirstier, more expensive cars in the fleet rather than smallest? Surely there are larger margins to play with and greater emission reductions to achieve?

13 September 2016
Ricardo are one of the finest automotive development companies around, but this mild hybrid doesn't sound to me like there's much further to go in development terms. Ricardo were also involved in the full hybrid prototype with Jaguar, of an engine which ran at a sweet-spot of around 2000rpm to provide power only as a generator - the car itself had a fully electric drivetrain. This means that batteries can be small, the engine can be tuned for optimum efficiency, and the car can run on electric power alone for limited period without any range anxiety. Seemed the future to me at the time.


13 September 2016
...Article 50 ASAP. Then we can have all the cars with decent engines and performance, whilst the eu can get stuffed.

13 September 2016
TS7 wrote:

...Article 50 ASAP. Then we can have all the cars with decent engines and performance, whilst the eu can get stuffed.

You are woefully misinformed. UK manufacturers will make cars that comply with EU rules, otherwise exports will dry up and factories will close. EU regulations will continue to define UK car market - however, we now we will just have to accept them rather than have a say in them, thanks to stupid Brexit vote.

14 September 2016
scrap wrote:
TS7 wrote:

...Article 50 ASAP. Then we can have all the cars with decent engines and performance, whilst the eu can get stuffed.

You are woefully misinformed. UK manufacturers will make cars that comply with EU rules, otherwise exports will dry up and factories will close. EU regulations will continue to define UK car market - however, we now we will just have to accept them rather than have a say in them, thanks to stupid Brexit vote.

That's garbage. If the EU were to reject our cars we would simply respond in kind and then buy the home produced cars ourselves. We are far better off out of the EU, staying as an independent nation and not being swallowed up into the one big European country which is increasingly imminent.

I don't need to put my name here, it's on the left


13 September 2016
How many other countries will follow the Norway target? Norway to 'completely ban petrol powered cars by 2025'. Ironic given they make a lot of money selling petroleum to the rest of the world. What would be radical is if they decided to leave this in the ground.


Add your comment

Log in or register to post comments

Find an Autocar car review

Driven this week