Audi: Diesel do nicely
11 August 2014
Despite the rise of alternative fuels, it is diesel that will still be the cornerstone of business car movement for the foreseeable future, Audi has mapped out the next few years of its diesel development. Nick Gibbs reports.
The talk of the conferences may all be about forthcoming electric or even fuel-cell propulsion, but at Audi the future is still very much diesel.
Even the rise of ever more frugal petrols isn't going to stop the TDI: "Gasoline technology will not supplant the efficiency of diesel," opined Audi head of engineering Ulrich Hackenberg at recent event attended by BusinessCar.
It's how that diesel technology will be applied that gets clever. Audi in the UK right now sells conventionally powered low-CO2 Ultra versions of the A4, A5 and A6, with the first V6 diesel Ultra in the pipeline: an A7 with CO2 emissions of just 122g/km. Frugal though they are so far, none in that range fall below 100g/km, leaving the tiny diesel A1 supermini and the new E-tron plug-in hybrid A3 the only real sub-100g/km tax-efficient options.
Joining them next year, however, will be the first low-emission cars with real boardroom appeal. Hackenberg said Audi will launch a plug-in hybrid diesel using the current three-litre V6 that'll drop below 100g/km, appearing first in the A8 then the bigger Q-badged SUVs.
Combined with the electric motor, these cars will produce a huge 516lb ft of torque that Audi likens to having a petrol V8 under the bonnet.
At the lower end will be the introduction of VW/Audi's new 1.4 three-cylinder diesel, which will first come in the A3 and then also be applied to bigger cars such as the A4 but with electric hybrid back-up. Hackenberg said customers would be fine with a small engine in more expensive cars. "I think there will be acceptance for strong high-torque engines with the right performance," he told us.
The key to all this flexibility is parent VW's new range of modular diesels. Dubbed EA288 internally and first seen on the new Golf in 2.0-litre TDI guise, this completely new range of diesels can be used either transversely mounted in cars with the MQB architecture like the Golf, A3 and new Passat, or the they can be used longitudinally in the so-called MLB platform cars that will kick off next year with the new A4 and stretch all the way to big SUVs like the Q7. The lightweight aluminium three-cylinder diesel is a version of this.
Audi points to the low friction of the engine as being key to its efficiency, with smooth-running parts such as roller bearings for the balancer shafts allowing more of the bang to be turned into propulsion. We tried it out in its latest application as fitted to the Q5 SUV and found it to be torquey enough for a higher-weight, more costly car like the Q5, but with CO2 cut to 129g/km (equivalent to 58mpg combined).
For more sporty diesel applications Audi is turning into production reality an innovation from its diesel Le Mans cars: an electric turbo. This is better named an electric compressor (or 'e-booster' in Audi speak) that spins up incredibly quickly to force air into the turbo at very low revs and so cutting turbo lag to zero. According to Hackenberg this will be first seen in a sporty SQ7 version of the new Q7 SUV due next year that uses the latest 3.0 V6 TDI as a base.
Audi has to meet internal targets to help the VW Group achieve its aim of averaging 95g/km of CO2 by 2020, and according to Hackenberg, 50% of that will come from combustion engine development. Of the rest, 30% will come from alternative powertrains, but Audi predicts for 2030 that, although 40% of all vehicles sold will be electrified, half of those are hybrid, meaning 80% will have a combustion engine of one sort or other. Given that 50% of UK Audi sales are to fleets, the business buyer's long-term relationship with diesel is a long way from being over yet.
Driving the latest oil-burners: A7 Ultra:
This joins as part of the large hatchback coupe's facelift and bumps power by an extra 14hp to 218hp from the old base V6 diesel while also slashing emissions to an official 122g/km, meaning 60mpg is theoretically possible. Directed through a seven-speed dual-clutch gearbox, the power delivery is just on the right side of acceptable for a car costing from £45,875, and the chattery diesel noise is suppressed to the point it's not offensive. The A7 is Audi at its more playful, and the interior options include wood trim pinstriped to resemble the decking on a luxury yacht.
Driving the latest oil-burners: RS5 TDI
This concept is one looking like it'll make production, and even RS petrol purists would agree the on-rush of acceleration from the electric-turbo-boosted V6 TDI is true to Audi's performance badge.
An electric compressor pushes air to the first of two turbos to apply torque almost instantly, given it the punch of a Tesla electric car off the line. Audi reckons the acceleration to 62mph takes around four seconds, but despite its 385hp we'd reckon official economy would match the current A7's BiTDI 166g/km and 45mpg. Expect it to join the line-up of the next A5 range.