It should never come as a shock that when discussing vehicles these days, two topics invariably find their way into the conversation; fuel efficiency and performance. It almost seems counter intuitive for both of these things to be able to co-exist, let alone work together to ensure the consumer has the best of both worlds. With the advancements in automotive technology, these two seemingly opposing ends of the spectrum are moving closer and closer together, and can no longer be described as mutually exclusive ideals, where preference given to one comes at the detriment of the other. One OE component in particular, the tire, is making impressive strides to bridge the gap between the two.
Automakers are under incredible amounts of pressure to reach government imposed fuel efficiency standards. Take the CAFE standard for example. CAFE, or Corporate Average Fuel Economy requires vehicle manufacturers to comply with the gas mileage, or fuel economy, standards set by the Department of Transportation in the United States. In 2011, the CAFE standard was set at 27.5 mpg, which was subsequently raised in 2012 by the Obama administration to 54.5 mpg, a standard to be reached by 2025 (this proclamation in essence makes it the defacto Canadian fuel efficiency goal). Failing to adhere to the standard can result in coffer-emptying penalties being levied against the manufacturer, and are calculated using the formula below:
Being forced to pay such a heavy penalty can land a player in the automotive industry in a pretty tough spot; although faced with such a lofty goal and the threat of a mind-numbing fine, can, believe it or not, be viewed as something good for the industry. I guess you can say that a high standard has the ability to light a fire beneath a manufacturer to innovate and develop new and improved technology.
Tires continue to play a role towards improving the fuel efficiency of vehicles, and automakers are treating this oft underrated component as a key player in reaching the 2025 target. That being said, tires are not impervious to wearing out, and while customers will engage in a collective fist pump at their ability to save at their local gas station, they won’t want those savings to negatively affect performance and safety.
Among the different approaches manufacturers are taking: improving the rolling resistance of tires. Rolling resistance, for those who don’t know, refers to…
…the loss of energy generated due to the repeated deformation and reformation of the tire as it comes into contact with the road.
This motion creates heat, which is then dissipated into the environment, resulting in a waste of energy – and when your vehicle is producing wasted energy, its overall fuel efficiency is lowered.
To combat rolling resistance, manufacturers will likely turn to, of all things, thinner tires – much like the new Bridgestones seen on the i3 and i8 BMW. Tires like these reduce the vehicle’s footprint on the road, reducing the amount of rubber coming into contact with the asphalt, thereby reducing the amount of energy lost to rolling resistance. Bridgestone claims their “Ologic technology” tires deliver better overall aerodynamics and rolling resistance while still offering a substantial grip on less than ideal road conditions. The discerning vehicle owner needn’t worry about the loss of aesthetics – thinner tires actually look pretty cool.
The use of advanced sensors in maintaining performance
A TPMS (Tire Pressure Monitoring System) currently monitors the internal air pressure of tires, informing the driver of inadequate pressure levels via gauge or other dashboard display. This in and of itself is handy for making sure you’re getting the most efficiency out of your tires; knowing when your tires are operating below peak efficiency can save you miles of lost energy. The engineers over at Continental Tire the Americas want to take the system one step further; by using sensors to measure tread depth. This application has less to do with maintaining efficiency than it does performance.
Some experts believe that as the tread wears down on your tires, fuel efficiency actually increases.
As tempting as it may be, you have to be careful when it comes to wearing out tire tread. While fuel efficiency may rise, the overall effectiveness of the tire lessens as the tread wears away. Conti’s sensor system works as you might suspect – the sensors compare the gradual degradation of your tire’s rolling characteristics with a set of control data and notifies the driver that a tire change is due. Obviously, this system is more concerned about ensuring your vehicle is performing as it should – but it doesn’t mean that you can’t use the information to run at both peak efficiency and performance.
Sensors can also play a big role in helping to determine if the permissible tire load has been exceeded. It’d work like this: sensors embedded in the tire tread can detect the size of the contact patch and measure the vehicle’s characteristics to determine whether or not the load has been exceeded. The heavier the load, the more pressure is put on your tires – and the larger the contact patch becomes. Exceeding the load capacity can not only lower the efficiency of your tires, it can be downright dangerous.
While the line between fuel efficiency and performance increasingly becomes a blurred one, this should not be a cause for alarm; we as consumers need only do our homework and seek the advice of a qualified professional to steer us in the right path.