Podcast Summary
Expert Jason Fenski discusses cars accelerating from 0 to 60 mph in under 3 seconds: Cars accelerate quickly by exceeding the coefficient of friction of 1, and future advancements are on the horizon
Jason Fenski, a mechanical engineer and YouTube car guru with over 600 million views on his Engineering Explained channel, was brought on StarTalk to discuss the science behind cars accelerating from 0 to 60 mph in under 3 seconds. This topic had sparked great interest from the audience, who were eager to learn from experts in Formula 1 and NASCAR. Jason explained that cars achieve such impressive acceleration by exceeding the coefficient of friction of 1, which is typically the maximum under normal conditions. He also hinted at future advancements in this area. The audience was intrigued by the prospect of delving deeper into the world of car physics with an expert, and StarTalk promised to bring on guests from Formula 1 and NASCAR in the coming months.
Limit of acceleration goes beyond 1g, influenced by tires and testing standards: Tires enable acceleration beyond 1g and testing standards impact reported 0-60 mph times, reducing price disparity between high-performance electric and gasoline cars
The limit of acceleration for a vehicle is not strictly limited to 1g, as demonstrated by cars decelerating from high speeds in short distances. Tires play a crucial role in enabling acceleration and deceleration beyond this limit. However, the testing standards for measuring 0-60 mph times can result in misleading numbers due to the inclusion or exclusion of rollout. For instance, a Tesla reportedly achieving a 1.99-second 0-60 mph time would actually be closer to 2.3 seconds in reality. The price disparity between high-performance electric cars and traditional gasoline-powered cars has been significantly reduced due to the capabilities of electric motors. The discussion also touched upon the fact that Tesla, Ferrari, and Porsche represent different types of motors, with Tesla being electric, Ferrari being hybrid, and Porsche being internal combustion. The implication being that the comparison is not entirely fair due to the fundamental differences in these powertrains.
The texture of the road and tires impact acceleration: Smooth roads limit tire grip, textured roads allow for more, electric motors provide immediate torque for quick acceleration, and ideal scenario is for both tire and road to have some texture for optimal grip and acceleration.
The texture of the road interacts with the tires in significant ways when it comes to acceleration. A smooth road limits the tire's ability to dig in and push off, while a textured road allows for more grip. However, if the tire is completely flat and the road is textured, the tire can dig into the road too deeply, reducing its effectiveness. The ideal scenario would be for both the tire and the road to have some texture to allow for optimal grip and acceleration. Furthermore, the discussion touched upon the differences between electric motors and internal combustion engines. While both use different energy sources, electric motors provide immediate torque, allowing for quick acceleration, while internal combustion engines require revving up to reach peak torque, resulting in a delay in maximum acceleration. Additionally, the conversation mentioned the use of glue on drag strips to improve starting performance and the comparison of Tesla's claimed 1.98 second 0-60 mph time to that of a Ferrari, raising questions about the validity of such comparisons. Overall, the discussion highlighted the complex interplay between tires, roads, and engines in achieving optimal acceleration.
Electric motors vs Wankel engine: Speed and Fewer Moving Parts: Electric motors outperform Wankel engines in speed and require fewer moving parts, but Wankel engines offer high power density in a compact size.
Electric motors respond much faster than combustion engines due to the nature of their power sources and mechanisms. While combustion engines require a series of events to occur, such as intake, compression, power, and exhaust strokes, electric motors excel at rotating things and require fewer moving parts. Historically, the Wankel engine, a type of rotary engine, was popularized for its fewer moving parts and improved reliability during an era when car engines were less reliable. However, its return today is not as significant due to advancements in technology and reliability, and it is now being used mainly as a range extender for electric vehicles. The Wankel engine's biggest advantage is its compact size, as it can have three chambers for the combustion process occurring simultaneously, resulting in high power density. Despite its disadvantages, some enthusiasts may still be drawn to it for its unique characteristics.
Standardization is essential for fair car comparisons: Major companies and testing organizations apply weather corrections and use consistent tracks for fair comparisons, but tire choices can lead to differences in results. Effective use of grooves on roads is a design element that prevents cars from drifting off course during high-speed turns.
Standardization is crucial when comparing the performance of different cars. Jason Fenske, the creator of Engineering Explained, explained that major companies and testing organizations apply atmospheric weather corrections and use consistent tracks to ensure fair comparisons. However, tire choices can lead to differences in results. In the example of Tesla, they chose a specific track and required the use of glue on the tires, preventing MotorTrend from conducting their own test until later. The effective use of grooves on roads, inspired by NASA's space shuttle runways, is a design element that prevents cars from drifting off course during high-speed turns. This standardization and consideration of design elements are essential to accurately compare the capabilities of various vehicles.
Tire design impacts vehicle performance: Off-road tires optimize ground contact for better grip, while smooth surfaces limit speed due to aerodynamic drag.
The design of tires and their tread patterns significantly impact a vehicle's performance, particularly in off-road conditions. The tread on off-road tires is designed to maximize contact with the ground, even at extreme angles, allowing for better grip and improved acceleration. Conversely, on smooth surfaces like racetracks, aerodynamic drag becomes the limiting factor, making it increasingly difficult to achieve higher speeds despite having more power. This is due to the force of drag increasing at a faster rate than the power output as velocity increases. Understanding these principles can provide insight into the unique design considerations for various types of vehicles and the challenges they face in different environments.
Drafting improves fuel efficiency: Drafting behind larger vehicles or objects can significantly increase fuel efficiency by reducing vacuum and making the following vehicle more aerodynamic.
Drafting, or riding in the slipstream of a larger vehicle, can significantly improve the fuel efficiency of a car. This phenomenon was demonstrated when the speaker observed his miles per gallon increasing dramatically as he got closer to an 18-wheeler truck. This concept is similar to wake surfing, where the surfer uses no energy to ride the wake of a boat. Electric vehicles also benefit from this effect, and while there isn't an electric equivalent to a turbocharger, increasing the size of the battery can result in more power output. The efficiency gains from drafting come from reducing the vacuum pulling the vehicle backwards, making the following vehicle more aerodynamic.
Larger battery packs enable faster speeds but bring challenges: Larger battery packs increase energy for faster speeds, but add weight and air resistance, limiting practical top speeds. Focus may shift from maximum speed to other attributes like longer range, lighter weight, and better handling.
Larger battery packs in electric vehicles enable faster speeds due to the increased energy available for discharge. However, the challenge lies in managing the increased weight and air resistance that comes with a larger battery and vehicle size. The practical limits of electric vehicle speed are not yet clear, but it's important to consider other factors like handling and maneuverability beyond top speed. Ultimately, the focus may shift from maximum speed to other desirable attributes like longer range, lighter weight, and better handling for electric vehicles.
Electric vehicles face challenges in long-distance travel and heavy applications due to energy density and weight: Electric vehicles struggle to replace fossil fuels in long-distance travel and heavy applications due to energy density and weight limitations, hindering their practicality.
The limitations of energy density and weight make it challenging for electric vehicles, particularly those used for long-distance travel or heavy applications like commercial aviation, to fully replace traditional fossil fuel-based energy sources. The discussion highlighted the historical struggle with steam engines and their inability to power airplanes due to weight, which is a similar issue with electric batteries today. Despite the advantages of electric vehicles in terms of efficiency, the vast amount of energy required for long distances necessitates a significant amount of battery weight, making the overall vehicle heavier and less practical for certain applications.
Hydrogen's Challenges for Vehicle Use: Hydrogen's clean emissions come with logistical challenges like low energy density, high volatility, and the need for high pressure or cooling for efficient storage, making it a complex solution compared to electric cars.
Hydrogen is a potential fuel for vehicles that produces only water as an emission during combustion, making it a cleaner alternative to gasoline. However, hydrogen has its challenges, including its low energy density requiring large storage tanks, high volatility, and the need for high pressure or cooling to liquefy it for more efficient storage. These factors make hydrogen a complex solution for widespread vehicle use, unlike electric cars that are gaining popularity due to their simpler infrastructure and increasing efficiency. The hydrogen 7 car experiment by BMW in 2007 demonstrated some of these challenges, particularly the need for constant refrigeration to keep the hydrogen from evaporating and wasting the fuel. Ultimately, the trade-off between hydrogen's clean emissions and its logistical challenges is a topic of ongoing research and debate in the automotive industry.
The future of transportation energy: Oil vs Alternatives: While oil is a readily available energy source for transportation, its extraction comes with significant environmental costs. The future seems to be a combination of batteries and solar energy for a more sustainable and efficient solution.
While there are alternative fuels like biofuels and synthetic fuels, they come with their own challenges and limitations. The oil in the ground, on the other hand, is a free and readily available energy source for transportation. However, its extraction comes with significant environmental costs. The most promising solution for the future seems to be the combination of batteries and solar energy, which is more sustainable and efficient in the long run. Ethanol fuels, while used in some racing series, have their own debates surrounding their emissions and efficiency. Corn-based ethanol, for instance, may only offer a 40% improvement over gasoline at best, and there are better alternatives like sugar-based ethanol. Ultimately, a mature and purposeful approach is needed to transition towards a more sustainable energy future.
The Environmental Impact of EV Batteries: Electric vehicles offer numerous benefits but their batteries, containing rare earth minerals, can contribute to pollution if not properly recycled. As the market for EVs grows, battery collection and recycling is expected to become a profitable industry.
While electric vehicles (EVs) offer numerous benefits, such as reduced emissions and improved efficiency compared to traditional gasoline-powered cars, it's crucial not to overlook the environmental impact of disposing of EV batteries. These batteries contain rare earth minerals and, when discarded, can contribute to pollution if not properly recycled. The cost-effectiveness of recycling is currently a significant factor, but as the market for EVs grows, it's expected that battery collection and recycling will become an industry in itself, driven by profit incentives. Additionally, the production of EVs also has a carbon footprint, which is often overlooked when calculating the environmental benefits of driving electric. Overall, it's essential to consider the entire life cycle of EVs, from manufacturing to disposal, to fully understand their environmental impact.