Volkswagen, as you’ll have read in last month’s issue, has just launched the full BlueMotion version of the latest Golf, with a host of fuel-saving features that make the car a remarkable 15 per cent less thirsty than its BlueMotion predecessor, with an EC Combined figure of 88.3mpg and CO2 emissions of just 85g/km.
Hyundai’s i20 Blue Drive matches that 85g/km, but the Golf is a full-size family-friendly hatchback, not a supermini, and the figure is achieved using a 109bhp 1.6-litre engine, as against the i20’s smaller 74bhp 1.1-litre unit.
Volkswagen’s pedigree in offering fuel economy model variants began well before the BlueMotion badge was first applied to the 2006 Polo though. Back in the early 1980s, petrol Polos and Golfs were offered in Formel E trim, with various modifications to boost fuel economy, though Britain was denied the 1.6-litre diesel Formel Es that were available in mainland Europe.
The Golf Umwelt diesel of 1991 and the 1993 Golf Ecomatic carried the theme forward and many of the fuel-saving principles developed back then are still evident in the latest Golf BlueMotion. It’s interesting to make some comparisons with the 1993 Ecomatic, which employed some technology that has not been carried forward.
It featured a cunning, clutchless manual transmission, and would freewheel when the accelerator was released, and the engine shut down after a further 1.5 seconds of accelerator inactivity, in a preview of today’s stop-start technology.
Supplementary pumps were used for steering assistance and coolant circulation, along with an electric vacuum pump for clutch operation, and the engine re-started automatically if the braking system ran short of vacuum assistance.
Engine restarts simply required an accelerator pedal depression, and the Ecomatic’s urban cycle fuel consumption of 61.4mpg was 40 per cent better than standard models – the pay-off from the long periods of deceleration and standstill during the urban cycle.
It shows just how far things have now progressed that the new BlueMotion’s urban cycle figure at 74.3mpg is over 20 per cent better still, while the power and performance have leapt from the non-turbo 1.9 Ecomatic’s 64bhp and 0-62mph in 17.5 seconds to 109bhp and 0-62mph in 10.5 seconds.
Specific gains over the previous generation BlueMotion have been achieved through 63kg of weight-saving, engine-related modifications, super low rolling resistance tyres running at higher air pressure, longer gear ratios, in addition to aerodynamic modifications.
The aerodynamic resistance is around 10 per cent less than other standard Golf models, derived from a 10cm lower ride height, a roof spoiler, rear window lateral air guide elements, a masked front grille and partially closed air inlet screens, as well as the optimisation of the cooling system airflow, special air-heating under-floor panels, optimised brake cooling channels, and a C-pillar spoiler.
At the heart of the new Golf BlueMotion though is a new, more powerful, 1.6-litre 109bhp common rail 16-valve TDI unit from the new EA288 engine series that meets the upcoming Euro six emissions limits and develops its maximum torque of 184lb ft from just 1,500rpm.
Efficiencies include reduced internal friction, a clever thermal management system with a shortened warm-up phase and exhaust gas recirculation. There’s a cylinder pressure sensor, a two-stage oil pump, a switchable electric water pump and a water-cooled intercooler located in the intake manifold, which all play their part in reducing fuel consumption and emissions.
In 2010, a Passat BlueMotion 1.6 TDI set a world mileage record in Europe, recognised by the Guinness Book of Records, achieving 1,526.63 miles on a single 17 gallon tank of fuel, equating to 89.8 mpg for the actual trip.
With only a 50-litre (11.1 gallons) fuel tank, the Golf would need to hit over 130mpg to beat the Passat’s record, which seems to be an impossibly steep target, but you can be sure that, with a 94.2mpg extra urban EC consumption, many drivers are going to try and crack the 1,000 miles barrier between fill-ups.