Formula One Engine Efficiency

Rules and Regulations

Fig. 1: Haas VF-16 Formula One Car. (Source: Wikimedia Commons)

Formula One cars, like the one in Fig. 1, are built for one thing, and one thing only: speed. They are built to accelerate quickly and maintain high levels of speed so over the course of the race, the average speed is anywhere from 100-150 mph. Although there are many rules and regulations for the Formula One car build, gas, fuel, etc. To win the Formula One World Championship, you have to be the best driver, and have the best car. And having the best car in this age, means having the most efficient car. So much has changed efficiency wise to the Formula One car over the years, that they have even adapted the rules the account for these changes and make the race more challenging. A major rule change that occurred in 2014 states that drivers will have to complete their race on 100kg of fuel or less which was marked down from the previous years' when there was no limit and formula cars were typically using 150 kg of fuel, and the max flow rate cannot exceed 100kg/hour. [2] Another rule change that took place in 2014 was the 2.4- litre V8 engines have been replaced by 1.6-litre V6 turbo engines. This means that engine power will be a large performance differentiator. [2] Fig. 2 displays a pre-2014 Forumula One engine. These are just a couple major rule changes that occurred in 2014. Let's take a look at why these changes have been made and what they mean for the future of all cars.

Street Cars vs. 2014 and Newer Formula One Cars

Fig. 2: 2008 Ferrari Formula One Engine. (Source: Wikimedia Commons)

The key reason the rules have recently changed is because Formula One builders have now built a car that might actually be greener than the "green" cars that we have on the road! Formula One cars are similar to road cars in a number of ways: brakes, suspension, internal combustion engines, transmissions, and wheels are used in the build of both cars, but the average U.S light vehicle fuel efficiency in the year 2014 and 2015 was about 25.3 mpg whereas a Formula One car's mpg is significantly less . [3] Based on this alone, you would not assume that the Formula One cars might actually be more efficient. What makes the F1 cars so green is their thermal efficiency. While road cars have been stuck around 30% thermal efficiency, Formula One Cars have exceeded 45% and are continuing to improve. [4] Additionally, most cars on the road have engines that are four, six, or eight cylinders. When you increase the number of cylinders, you increase the potential for power, but at the cost of not getting as good of gas mileage as cars with fewer cylinders have. This means that Formula One builders have taken out two liters at the potential to lose power, but save gas. This doesn't seem to make sense for a Formula One racecar whose only goal is speed. So why were these changes made? The regulations were framed with the intention of encouraging teams to create more efficiency through their engine design! So where does the Formula One race car make up for the lost power?

What Makes This Engine Tick

Here is the major difference between road cars and Formula One cars: energy recovery systems, and there are two of them! These post 2014 Formula One cars have two different ERS systems that work to recover heat and kinetic energy that would otherwise be lost, and turn them back into useable energy. [5] With two sources of recovered energy to use the limit on the amount of power they can generate has been raised, therefore making up for the removal of the two cylinders from the engine.

KERS and ERS Systems

Fig. 3: Toyota Prius.(Source: Wikimedia Commons)

The KERS system is the first of the two energy recovery systems. This system has actually been around for a while, but since 2014, it was made more efficient. This system harnessing kinetic energy from the rear axle while the driver is braking through the use of an electric motor. This energy is then stored in a battery pack and then released upon acceleration. Prior to 2014, the KERS system was allowed to produce 60kW for up to 6.7 seconds per lap. Post 2014, the KERS system is allowed to produce 150 kW for up to 30 seconds. [2] The second motor in the Formula One car build is an electric motor that harnesses energy from the turbo that in any other car would get wasted as heat. [5] These two motors supply the extra power Formula One cars need while also increasing their fuel efficiency by about 35%. [2]

Are Road Cars Using These Systems?

This idea of harvesting energy from braking has not only been thought of by Formula One racecar builders, but also by Toyota! As the number of Prius's on the road has increased year by year, it is not surprising to see why this is happening. Toyota took the idea of Formula One KERS system, and applied it to the Prius, displayed in Fig. 3, to make regenerative brakes. How regenerative brakes work is when the brakes are pressed, electric motors mounted on the drive wheels reverse their direction of rotation, creating a torque and moving counter to the cars direction, helping the car slow whilst also acting like a generator storing energy in the battery. [1] This system is what helps the Prius be one of the most fuel-efficient cars in the United States!

© Taylore Jaques. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.

References

[1] C. C. Chan and K. T. Chan, Modern Vehicle Technology (Oxford University Press, 2001).

[2] A. Benson, "F1 2014: All Aboard the 'Power Train' - New Rules Explained," BBC Sport, 25 Jan 14.

[3] N. Naughton, "Average U.S. Mpg Edges Up to 25.5 in May," Automotive News, 4 Jun 15.

[4] L. Edmondson, "Is an F1 Car More Energy Efficient Than an Electric Vehicle?," ESPN, 8 Dec 16.

[5] P. Marks, "7 Tricks to Keep F1 Cars Fast and Fuel-Efficient," New Scientist, 12 Mar 14.