MOTOR MOUTH
PURPORTED FUELSAVING TECHNOLOGY A NON-STARTER
Last month, I was asked to choose which of the features in a modern car annoy me the most. Because I could, unfortunately, only pick one, I chose the infernal keyless entry system, that supposed modernization whose main effect seems to be the constant misplacement of every automotive key fob I come in contact with.
Truth be told, though, I find the modern idle start-stop function much more of a nuisance.
Better, for me at least, is the constant, but mild thrum of an internal combustion engine at idle than the intermittent silence, not to mention the abrupt walk-up, of an engine that can’t decide if it’s awake or asleep. Only mildly infuriating in a four-cylinder car, it’s seriously irksome when a big V8 or a heavy piston turbodiesel has to rumble to life at every stop sign. The only reason I didn’t choose it as my No. 1 annoyance is because, unlike keyless entry, you can always shut the bloody thing off.
Manufacturers claim such hightech wizardry is necessary to meet increasingly stringent fuel economy regulations, start-stop only one of myriad detailed technologies — more efficient air conditioning systems, radiator shutters and other aerodynamic aids, etc. — being introduced in the quest to meet the United States’ mandate for a 54.5 mile per U.S. gallon fleet average by 2025.
But does it work? More importantly, will you see any benefit?
The answer, like almost everything about fuel economy, is complicated. I went out and, trying to replicate typical city driving, tested Audi’s new 2016 A6 with the start-stop function turned on and off.
As unscientific as my little experiment was, I achieved about a six per cent fuel economy increase — 9.6 litres per 100 kilometres with the system on, and 10.2 L/100 km without — by having the engine stop at every stop sign/street light/railway crossing I encountered. So, it works.
Indeed, since my tester was an already fairly frugal 3.0-litre turbodiesel, chances are gasoline engines, especially of the larger variety, will save even more.(Edmunds.com, testing a supercharged Jaguar F-Type R, recorded a 10 per cent increase.) That seems pretty darned impressive ... until you start doing the math.
Let’s assume your car, a typical four-cylinder gas engine family sedan, averages 10 L/100 km in the city. Let’s further assume you’ll save a real-world five per cent with an idle start-stop system by having the engine diligently extinguish itself when stopped.
Plug all the numbers — $1.20 a litre for regular unleaded, 7,500 urban kilometres a year, etc. — into your smartphone app and it turns out you’ll save ... about $50 a year.
The number seems even less impactful when you consider that to incorporate start-stop into the modern automobile, one needs a heavier-duty starter (because of its vastly increased cycling), ditto the battery and sometimes even a second oil pump (so oil pressure builds more quickly, preventing engine and transmission damage).
Now, unless you believe automakers are absorbing the cost of all this added technology, there’s a price tag to this beefing up of engine.
Even factoring in a cost of $300 that’s at least a six-year payback, an extraordinarily long time to put up with something that can be, if you’re as sensitive as I am, a serious annoyance. So why bother? Well, the real motivation is found deep inside the 1,500 pages that are the new U.S. Corporate Average Fuel Economy standards.
To encourage the automakers to think frugally, the regulations allow for something called “off-cycle technology credits,” essentially a reward for incorporating gadgets for which the government testers can’t measure any discernible benefit in their laboratory testing but think will be of benefit to fuel economy anyway. There’s a raft of such do-dads — stopstart, various aerodynamic aids and even high-efficiency headlights are included — that garner automakers credits regardless of their benefit.
In the case of start-stop, it’s an automatic gain of two grams/mile of CO2 reduction for cars, while trucks, ever advantaged by the American government, get a credit for as much as 4.4 g/mile. Throw the entire suite of accredited gadgets at a car and the benefit can be as much as 17.8 g/ mile (for non-hybrid trucks), roughly equivalent to two to three miles per U.S. gallon. For an industry struggling to meet that ambitious 54.5-mpg figure, it’s a freebie few automakers can turn down even if they know the benefit to consumers is questionable.
And idle stop-start is hardly the only supposedly gas-saving technology benefiting manufacturers more than consumers. I recently tested Ford’s much-ballyhooed 1.0L threecylinder EcoBoost engine that powers the 2015 Focus SE.
I then compared it with the 2.0L four that powers the hatchback version of Ford’s compact.
At every highway speed tested, the 2.0L consumed less gas than the 1.0L. The 2.0L’s advantage was but 0.2 L/100 km, but that’s made more impressive when you consider Ford charges $1,600 extra for the 1.0L’s privilege of sucking back more gas and losing 35 horsepower.
Even in the city, the 2.0L often eked out another 0.2 L/100 km advantage. And, yes, the EcoBoost was even equipped with idle stop-start; the 2.0L, being Ford’s bargain basement powertrain, was not.
What is most interesting is how this high-tech gadgetry compares with more conventional fuel economy savings techniques, shortcuts that savvy consumers have employed for years. Thanks to some “efficiency program” software buried deep in my Audi’s tripmeter, I was able to determine how much fuel I was using with the car’s air conditioning system, the seat heaters and even the seat ventilators that came with my fully loaded A6 tester.
For instance, I know that the A6’s driver’s seat warmer, set to its highest position, consumes less than 0.1 litres of gasoline per hour, a mere pittance. Calling for max heat from the air conditioning system, on the other hand, will suck back a more serious 0.5 L/hr (maximum cooling, much to my surprise, consumes a little less).
Factor all those numbers again (6.0 L/100 km for the A6 on the highway at 100 km/h) and getting max heat from your vents on a cold February morning might reduce fuel economy by as much as eight per cent. Conversely, forego the ventilation system and just heat up the seats and the steering wheel and you’ll be wasting less than two per cent.
No wonder then, that EV makers, even more desperate for range than conventional automakers are for fuel economy, recommend owners use their seat heaters rather than the a/c system.