By the year 2025 the Corporate Average Fuel Economy (CAFE) standard will be 54.5 MPG. This means that for every automotive company selling cars in the United States the average fuel economy of all of the cars that company sells must be 54.5 MPG. If that seems like a monumental task that you don’t expect to see happen then you’d be correct. The way the government measures fuel economy is not in a real world environment and gives unrealistically high values. So, you will likely see the CAFE be in the high 30’s (MPG) rather than in the mid-50’s. Nonetheless, this is drastically higher than what we see now.
In 2011, the way a corporation calculated their average fuel economy was changed and left many loopholes for car companies to jump through. Firstly, the fuel efficiency goals were made flexible. Auto manufacturers are left to “predict” the number of each type of car they will sell and calculate their average fuel economy using this metric. This is put in place to provide fairness in calculation during fluctuations in the market, which will inevitably happen, sometimes unpredictably, with change in oil prices, wars, etc.
The second major change is in the way this average is calculated. This came in the way of the implementation of a scalar for different sized cars. Now, fuel economy goals are based on the physical footprint of a car calculated by multiplying the vehicles wheelbase by its average footprint. No wonder Porsche continues to extend the length of the 911’s wheelbase (amongst many other handling and packaging reasons).
The third and most important for car enthusiasts is that not every company is going to have to face this as an independent company. I think the most obvious way to understand this is by looking at a company like Lamborghini. I don’t think they’ve made a car that has ever gotten more than 15 MPG in the entirety of their existence (The Huracan is advertised at 14 city / 21 highway, but I don’t believe it). Luckily for us, Lamborghini (along with Porsche, Audi, Bentley, Bugatti, Ducati and some other companies I don’t remember because they aren’t sold in the U.S.) is part of the Volkswagen Group. So, if Volkswagen sells 1,000 Golfs and Passats that can achieve high fuel economy standards then the company does not have a problem selling a few Lamborghinis.
Yet, even with some loopholes to exploit there is no way of getting around the fact that in order to be viable in the future companies are going to have to change the way they produce their cars. With R&D budgets increasing and new techniques being implemented, car companies are doing everything they can to increase fuel economy and these are some of the main ways they are doing it.
Smaller Displacement, Forced Induction Engines
Almost, every manufacturer in the world is finding ways to make their engines as efficient and small as possible. The most common way a car company will try to increase performance and efficiency at the same time is by slapping a turbo charger onto a smaller engine. Every company is doing this and not everyone is happy. While large burbling V8’s have characterized American pick-up trucks for decades, Ford is now offering their top of the line F-150 with a 3.5 L twin-turbo V6 instead of their larger 5.0 L V8. Ferrari’s newest (normal) production car the 488 GTB has forgone the 4.5 L V8 everybody loved from the 458 Italia and replaced it with a 3.9 L twin-turbo V8. BMW is developing a quad-turbo diesel engine that has a turbocharger ready for four different engine speed ranges. All of these companies have spent exorbitant amounts of time and energy trying to create a more efficient engine that maintains the performance and feel that customers expect. Yet, many people still complain about a non-linear power band or a muffled sound.
Sadly, it is inevitable that the days of the 7.0 L LS7 from Chevy have come and are going, quickly. But, with newer turbo technology, and a little help from your friendly neighborhood software engineer (and car stereos), these cars, I think, will perform better than ever and sound pretty good too (even if it is fake sometimes…BMW).
However, it is not only turbochargers that are being added. When Chevy was producing their new Corvette Z06 they wanted to use a high revving naturally aspirated engine, but were not able to meet emissions targets. So, they went back to the drawing board and supercharged their 6.2 L engine to give it 650 HP and 650 lbs-ft of torque. Not something I would complain about, especially when you get the added supercharger whine.
An easy way for a car manufacturer to increase fuel economy is to retune or change their transmission. Very simply, a transmission helps you get the proper amount of power to your wheels at a given speed. In different cars a transmission will work differently based on the amount of power you want. For most economy cars the goal is to deliver an adequate amount of power as effectively as possible. This means keeping the RPM of your engine in the optimal spot for as much of your drive as possible. This is commonly done two different ways.
The first is by shifting gears, like your typical automatic or manual car does. This is why so many manufacturers are developing transmissions with more and more gears. GM and Ford just jointly developed a 10-Speed Transmission so that they can keep their cars in the optimal power band at all times. Honda is rumored to be working on a triple clutch 11-Speed. This is drastically different from days of yore when 3 or 4-Speed transmissions were prevalent.
The second most common transmission, but only in economy cars, is called a Continuously Variable Transmission or CVT. This type of transmission is becoming more and more popular, but only in cars without a significant amount of horsepower (these types of transmissions cannot handle large amounts of power effectively). This transmission, as the name implies is continuously and infinitely variable which allows a computer to keep the car in the most efficient operating range. The simplest way to understand this type of transmission is to think of a two-pulley system where the size of one pulley is constantly varied to control the “gearing” of the car. This means that as you step on the gas and ask for acceleration from your car the “variable pulley” will decrease in size giving you more power and then increasing in size as you come off the throttle. During this entire process your engine speed will stay roughly the same, which is very different from what you would expect in a “regular” transmission.
Hybrid Powertrains and Regeneration
It is no secret that Hybrid cars are becoming more and more prevalent and many people are unhappy about this. Even Porsche is rumored to be working on a hybrid 911. Yet, three of the most powerful and exciting production cars in the world right now are hybrids (918, P1, LaFerrari). The technology and advancements in driving performance are very interesting as well. The AWD systems that are being developed are practical for both performance and safety, and the regeneration technologies are incredible. Most hybrid cars use their brakes to regenerate electricity, some use their combustion engines and some may even use their suspension in the future. Audi has announced that they have developed a technology to regenerate electricity for their hybrid vehicles. As the hybrid car drives down the road its suspensions turns the “up” and “down” motion from imperfections in the road into rotational motion. The energy from that rotational motion is then harvested through an alternator and used to charge a battery.
Companies are doing other things like adding start-stop features, taking weight out of cars and improving aerodynamic efficiency too. However, what I have highlighted are the most prevalent ways that auto manufacturers are trying to change their passenger cars. It is interesting to see what they come up with and I hope they are able to continue. In the mean time, enjoy driving your cars while you can, before they drive themselves.