“the diesel engine with direct fuel injection is the engine with the highest thermal efficiency” – Audi.
MALMO, Sweden – Diesel engines are under attack on many fronts, but Audi still believes they have a solid future and will even lead the way in saving fuel for a while yet.
Ever-tightening clean-air regulations make diesels more expensive to produce. Gasoline engine technology threatens too, with huge gains in fuel economy, all-round responsiveness and flexibility making them more diesel-like without the baggage. Battery-only cars, hybrids, plug-in hybrids and fuel cells are gathering on the fringes for an assault in the fuel economy stakes, but Volkswagen’s luxury subsidiary Audi says technology improvements mean that diesels will at least cling on to their huge market share in Europe for some time to come.
Battery-only cars like the Nissan Leaf rely on electricity alone. The Toyota Prius hybrid use a combination of electricity and gasoline and has a very limited electric-only capability. Plug-in hybrids use a combination of gasoline or diesel engines to provide power, and have a battery-only capability of around 30 miles. The car’s computer will also help generate electricity on the move. Extended range electric vehicles like the Chevrolet Volt have a small gasoline engine which generates electricity when the battery is empty. Fuel cell cars use hydrogen to generate electricity on board and the first examples will appear next year with the Toyota FCV.
But these developments won’t have much of an impact on diesels, or gasoline engines in Europe, for a while yet.
The drive towards battery-only cars has stalled, with buyers demanding prices halve and range doubles before they invest their own money, despite generous government handouts. When battery-only vehicles began to appear, first responders like Renault of France and its Nissan affiliate reckoned by 2020 around 10 per cent of the world’s car sales would be battery-only. Now Barclays Equity Research says this will only reach 1.5 per cent by 2021, with 3.3 per cent in Europe and 1.0 per cent in the U.S. Renault-Nissan has admitted it won’t make its target of 1.5 million electric vehicles by 2016, only selling about 120,000 so far.
So there is plenty of scope to still sell diesels, which Audi says will become yet more fuel efficient and clean.
At a diesel technology workshop, held here in Sweden, Audi said around 40 per cent of its engines sold since 2010 were diesels, and this will continue to at least 2020.
In Europe, close to 50 per cent of all new cars sold are diesels. Diesels have been slow to catch on in the U.S., but Audi managed to sell 158,000 in 2013, up 13.5 per cent on the previous year. Last year the Audi Q5, A6, A7 and A8 offered diesels. The little A3 sedan will have a diesel option in the U.S. later this year.
Ulrich Hackenberg, Audi technical development board member, said by 2030, 40 per cent of all new cars will be electrified in some way, while two thirds of them will be hybrids. But 80 per cent of cars will still have an internal combustion engine on board as part of a hybrid set-up, or a range-extender with a battery-powered car.
Hackenberg said the efficiency of diesel engines has increased by 30 per cent since 2000. By 2016, the carbon dioxide (CO2) emissions of Audi’s new cars will have fallen by a quarter compared with 2008.
Developments in coming years will be based on 48 volt technology which will allow electrification of many aspects of the diesel engine, including an electrically driver compressor. This will all but eliminate turbo lag. Audi provided demonstration cars at a race-track here to show how use of this compressor gets rid of the time-lag between flooring the accelerator and having the diesel engine react. 48 volt technology and lithium ion batteries will allow the physical electrical systems to be smaller and lighter. So-called renewable e-fuels use micro-organisms to produce synthetic diesel. Audi said this fuel will use no fossil sources, and won’t use crops diverted from food use. Turbo-charging will wring yet more power and efficiency from internal combustion engines.
Hackenberg said the Volkswagen Group – which includes Audi, sports car and luxury brands like Bentley and Lamborghini, and mass market companies like Skoda and SEAT, will achieve its E.U. target of average CO2 emissions of 95 grammes per kilometer (g/km) by 2020. That’s the equivalent of close to 60 miles per U.S. gallon. Most manufacturers have already reached the 2015 E.U. target of 130 g/km, the equivalent of 43 miles per U.S. gallon.
Hackenberg said 20 per cent of that target will be achieved by saving weight, improving roll resistance and aerodynamics, 30 per cent will come from alternative drive systems like natural gas, plug-in hybrids and full electric drive.
“The remaining 50 per cent will be reduced by fully utilizing the potential of our combustion engines. The key words here are reducing friction, efficient thermal management and optimized combustion,” he said.
“Our conclusion: At present and for the foreseeable future, the diesel engine with direct fuel injection is the engine with the highest thermal efficiency. And that makes the diesel the first choice for efficiency in the drive train,” Hackenberg said.