At a training centre in Germany, BMW cars were being put through their paces. Paddy Comyneased his foot off the pedals, and the results were astonishing
YOU CAN blame it on the Americans, but car users who take getting better fuel consumption to extremes have done nothing for the image of those who want to save fuel.
Hypermilers, as they are known, became infamous for their fanatical attitude to saving on fuel. Spurred on by rising oil prices and global economic recession, their goal was to glean as much distance from as little fuel as possible, but the often alarming methods brought them under attack.
Among these were driving at virtual crawl on highways and freewheeling in towns, causing tailbacks and irate commuters. Combined with bizarre modifications to make cars more aerodynamic, hypermilers were quickly established as more wacky than visionary.
Yet as I coast towards Ljubljana in Slovenia, having left Munich several hours earlier, sipping a minute amount of diesel on the way, you can start to see method in the madness.
I have gatecrashed BMW’s Efficient Dynamics Drive from Munich to Ljubljana – 450km using a variety of BMW’s more fuel-efficient engines, all with Efficient Dynamics branding.
While it may sound like a German tribute band or some edict from 1940s Berlin, Efficient Dynamics is in fact a combination of technologies to give the majority of the model range impressive fuel economy figures. For Irish motorists, that means not only savings at the filling station but lower taxes.
While it might be a little trite (after all, who would seek inefficient dynamics), the key ingredients are creative aerodynamics, stop/start technology and transferring unused kinetic energy to charge the car battery.
As usual, the end result is a set of impressive official fuel economy statistics, but the difficulty is that, after all their hard work, we get into their cars and drive them like they’re stolen.
That’s why I am being barked at (politely) by Jurgen Prost, an instructor from BMW’s driver training centre who, when not training rich Arab security staff how to avoid hijacking, shows fleet managers how to knock thousands off company fuel bills by driving a little bit smarter. I can tell I am irritating him. “Why, why are you using that gear?” he begs, clearly more used to dealing with trained ex-military men than leaden-footed exhausted Irishmen.
Everything I had thought I knew about fuel economy was stripped away by Jurgen and I was exhausted. Having just about matched the firm’s fuel economy figures in the 123d coupé and badly exceeded it in the 320d Efficient Dynamics, it was time for my one-to-one tuition. “The problem with most people is that they spend too much time braking,” says Prost as beads of sweat trickle down my brow. “The largest energy consumed is getting the car to move off from a standstill and drivers are constantly braking and then having to readjust.”
Here’s the thing. How many of us accelerate down hills? You probably do it without thinking. We all seem to think a two-tonne car won’t make its own way down a hill without the help of an engine and some petrol and quite quickly I am learning that this isn’t always the case.
Granted, as we drive out of Munich, through Austria and down some hills that you could hold an Olympic skiing event down, it’s not hard to see that the brake might be more useful than the accelerator.
But that, too, is causing Jurgen to bang his large German paw on the dashboard. Having got me to use the car’s gearshift indicator to get through the first few gears quickly and efficiently to build up my power to get up a hill, he now has me shift into sixth gear and let off the gas pedal totally. Does this mean I am careening down the hill with the delicateness of an avalanche?
Well no, I’m not, and it’s all down to engine braking. While gravity plays a role, the engine, while in gear, slows the car up, yet my fuel consumption remains zero. I can change the severity of the engine braking by changing into a lower gear. It works. I’m following lines of cars down a winding road and using no fuel at all, according to the car’s trip computer and Jurgen’s smiles of approval.
Whatever the German for “at last, you complete idiot, you seemed to have finally grasped the idea” is, I think it had been muttered a few times before this Eliza Dolittle moment: By George, I think he’s got it!
What was happening to the average fuel economy figure was pretty amazing, too. As I coasted up to traffic lights, carried my speed through corners, used careful throttle inputs and availed of the car’s stop/start technology, I was, at one stage, getting 2.2l/100km. That’s 128mpg. And by the time I stopped, including town driving, a stretch of motorway, some hills and various other obstacles, I had managed an average of 3.9l/100km in the 116d. That’s 72 mpg and was only beaten by a German journalist in a 320d Efficient Dynamics Edition car who managed 3.5l/100km and looked like he took these tasks seriously. Very seriously.
What was perhaps even more remarkable was that we weren’t all driving 320ds or 116ds. There were a 635d and a 730d there, in all their weighty, automatic transmission glory, and they still managed respectable averages.
Jurgen reckons the average driver can improve fuel consumption by as much as 25-30 per cent just by applying these driving techniques and being more careful about how they use the accelerator and brake.
That’s a pretty big figure, especially if you commute a lot. Saving one week’s worth of petrol per month just by being a little less leaden-footed and infinitely more aware is something that is as timely in terms of cost savings as it is noble from an environmental perspective.
