Nick Hayden and David Lister can’t grow facial hair, but their Nationals-bound science fair projects could save millions of dollars in fuel.
Hayden, who’s in Grade 7, and Lister, Grade 8, both set their scientific sights on improving fuel efficiency in modern cars and trucks.
With gas prices starting to climb again, it’s compelling science indeed.
Lister focused on the alternator, the under-the-hood generator that converts power from a car’s engine into electricity, which charges its battery and runs the lights, radio and other electrical systems.
More than 10 per cent of a car’s fuel consumption gets eaten up by the alternator, costing Canadian motorists more than $3.5 billion a year, said Lister.
“I wanted to figure out a way to replace the alternator completely, so it does not use up any gas whatsoever from the engine,” he said.
Lister immediately looked to the heat that bleeds off internal combustion engines.
“About 80 per cent of the fuel you buy just gets turned into heat,” said Lister. “I wanted to figure out a way to recover all that heat and convert it into electricity, and then use it to replace the alternator.”
To do so, he turned to 19th-century French technology.
In 1834, Paris physicist Jean Charles Athanase Peltier discovered by running an electrical current through the junction of two different metals, the two metals turn into a heat pump: one side absorbs heat while the other side radiated heat.
Fittingly, the heat pumps came to be known as Peltier modules.
Mini coolers are the most widespread users of Peltier modules. That’s why the inside stays cool while the outside becomes scorchingly hot.
Peltier modules can also work in reverse, said Lister.
By subjecting them to alternating heat and cold, the modules emit electricity. Perhaps enough electricity that sapping engine power with an alternator can be eliminated.
Lister took a four-stroke snowblower engine and fitted it with a cowling that funneled heat and hot exhaust towards two Peltier modules.
A high-powered fan blasted the other side of the modules with cool air to create a temperature differential.
“The greater the temperature differential the more electricity the Peltier modules produce,” said Lister.
Lister’s Peltier modules emitted enough power to light a small room with fluorescent lights.
That’s not enough to replace an alternator, but with six more Peltier modules mopping up every last ounce of heat, Lister estimates the alternator could, indeed, be rendered obsolete.
Cost is the only factor preventing Lister’s design from hitting auto assembly lines.
Peltier modules aren’t exactly cheap—Lister obtained them from a Russian supplier for $50 apiece. If a Peltier module apparatus were installed in a full-size automobile, it would cost between $10,000 and $20,000, said Lister.
“Mind you, your alternator costs you a few hundred dollars a year anyway,” he said.
Of course, in the age of hybrid vehicles, Lister’s device is a tantalizing addition.
Peltier modules could be bolted onto the average Prius and used to charge the car’s onboard batteries. The extra power would reduce the need to run the gasoline engine, and efficiency would increase.
The other science experiment focussed on semi trucks, the Yukon’s behind-the-scenes lifeline.
Every banana, every Big Mac and every litre of diesel enters the Yukon in the back of a semi truck, speeding through the vast highway distances that connect North and South.
These trucks use an “atrocious” amount of fuel, said Hayden.
A primary problem is that most semi trucks firmly disavow any notion of aerodynamics. Most modern cars have embraced streamlining. And with it, their gas consumption has plummeted. Meanwhile, truckers around the world continue to shell out millions of dollars to manhandle their boxy, wind-resistant behemoths along highways.
Trucks pull a heavy trailer and, due to their clunky designs, also hundreds of pounds of trapped air currents, putting undue stress on the engine and sapping fuel consumption.
Hayden wanted to see if he could tweak the modern semi-truck into efficiency.
To start, he purchased three scale-model semi trucks from the Wal-Mart toy department.
One was a typical 1970s-era truck—completely devoid of any attempt at aerodynamics.
The second was almost the same, but the cab was fitted with a sleeper unit.
The third truck was a more modern design, with smoother wind-friendly lines.
To test the vehicles, Hayden cobbled together an ingenious homemade wind tunnel.
The models would be placed within a length of stovepipe hooked up to a leafblower. A tiny string was attached to the model and tied off to a pivot, which, when pulled would press down upon an electronic kitchen scale.
When the leaf blower was switched on, the vehicles would be pushed slightly backwards by the rushing wind. The more they resisted the wind, the more they would pull back on the string, and the higher the weight value that would be measured on the scale.
Of the three trucks, the modern design immediately stood out as the most efficient.
Using the most efficient truck as his starting point, Hayden set about wringing it for every ounce of efficiency he could.
He started with the space between the cab and trailer.
That’s a notorious drag-inducer, said Hayden’s research.
Wind is sucked into the space and blown uselessly around before being ejected back into the airstream.
By simply placing a sleeve between the cab and trailer, Hayden found that drag dropped by up to 15 per cent.
The large running clearances of trucks is also a prime target for wayward wind currents. Hayden responded by fitting the trailer with side skirts that extended over the wheels. The skirts knocked off
another 10 per cent of the drag.
And, just for kicks, Hayden fitted a cone over the semi trailer’s rear doors. Surprisingly, it only reduced drag by three per cent.
Practicality of loading and unloading prevents the cone from ever making it onto North American highways, but some trucking companies have already begun to explore rudimentary aerodynamics.
Cab and trailer extensions have started to appear on highway trucks; the first industrial forays into side-skirts and cab-trailer sleeves.
In a world of ever-spiralling fuel costs, accordion-shaped connectors and full-fledged side skirts may soon be the norm, said Hayden.
On a scrap of paper, Hayden drew his idealized semi-truck of the future: a bullet-shaped cab, connected by an accordion sleeve to an airstreamed, Twinkie-shaped trailer.
An eye-catching, almost whimsical design. But a crucial innovation for a world of dwindling resources.
Contact Tristin Hopper at