A Portable Wind Tunnel
We built a portable wind tunnel for measuring EV efficiency and will be used to calculate the drag coefficients of Tesla and Chevrolet EVs. It sticks on the car windshield using suction cups. Pitot tube based anemometer. Jack had two choices to place the portable wind tunnel at mid ground level near the front air intake or place it on the roof. He said: I personally think that the mid ground level is the most accurate but it sticks out there and I was afraid of damaging it was just easier to place it on the windshield. He then found a little difference between the GPS speed and wind speed if drove it during the early morning hours on flat ground with a little turbulence. He was able to back calculate the Drag-Area and using the factory area and ODBII PIDs, get within a few percent of the factory number of Cd=.308. The number was .311. The PIDs are comprehensive and highly accurate. used a tire model for LRR tires. Next is the Model S.
CE 190
This fall Jack will be teaching Electric Vehicle technology at UC Berkeley again. The course is a comprehensive technical breakdown of the physics of electric vehicles.
Future of Mobility Podcast Interview: Innovation, Electrified Vehicles, Virtual Reality & More with Jack McCauley
I enjoyed talking with Brandon Bartneck of Future of Mobility. The following is an excerpt from my interview and to hear the full episode visit here. Encouraging Innovation Encouraging innovation in young children is incredibly important. Take me, for example. I never considered myself to be a “star” student. I spent my time doing other creative things like building models, working on eclectic trains, building, drawing, and making music. I even got a scholarship at 9 years old from Tinker Toys. If you find that you have a propensity for those things, or you have a child who does, it is important to foster that creative spirit. Academics will develop eventually, but creativity and innovation are equally as important. Biggest Opportunities for Improvements in Electric Vehicles There is a ton of innovation happening in electric vehicles right now. Just about every automaker is coming out with a similar electric vehicle. I see the main opportunities for EVs being solid state batteries. Batteries wear out and diminish in their capacity to deliver electrons. There is now an emphasis on using solid lithium batteries rather than lead acid batteries. Solid state batteries do not have as many issues as the others and have more potential to have longer battery lives. Energy management in electric vehicles is an area with significant room for improvement. Smaller EVs are less able to cool themselves down than larger vehicles. For example, the Chevy Volt versus an electric scooter. If we can figure out a way to keep the batteries at a cooler temperature, it would be a better way to manage the power content of the engine and batteries. Many places are making efforts to eventually have “EV-only” cities, as a way to become more environmentally friendly. Manufacturers need to have enough vehicles for that level of electric vehicle demand. In these “EV-only” cities, you will have the flexibility to drive further with smaller battery packs, which is more sustainable in the long run. One of the biggest advantages of an electric vehicle is that it has an ability to generate power. There is a reversible chemical reaction that occurs in an EV and can actually generate energy through the braking force of the electric motors. With my own electric vehicle, it costs me $6 to charge my battery from dead and I can travel 250 miles, more than I could in a gas engine and for less money. That is the biggest advantage I am seeing. Something I, and My Students, Have Learned While Building and Improving Their Own Electric And Hybrid Vehicles While building electric vehicles with my students, we have come to learn several things. One challenge we tackled was figuring out how we could make the hybrid vehicles more efficient. Our hybrid model has a small gas engine, which we have only charged twice. That engine cannot power the entire vehicle, but it is enough that when you park it, the braking force tops the battery off. In hybrid vehicles, if you have a battery that takes the energy from braking and a battery from propulsion, when you stop, it tops off the propulsion battery from the braking. We tried to separate the two to control how much the battery is being used, so we can control the temperature. Our EV has no brakes, just all regenerative braking. If you have an electric vehicle that is at the top of a hill with fully charged batteries, and you want to go down hill, you can’t use the brakes because there is nowhere for the regenerative energy to go. If you had two motors, one in regen mode and the other in braking mode, the braking force would not regenerate power and would just have a braking force without using the battery. Valuable Career Advice for my Students If a student wants to make an impact, I would tell them three things. First, maintaining relationships and staying in touch with people is critical. It can be as simple as calling them up just to say hello. Throughout my career, I have stayed in touch with past coworkers even from my very first jobs, and it has paid off. The second thing is, it is great if people remember you, but you should also make a great effort to do the job well. Be honest and easy to work with, do your best to get along with people. Last, do something you love and that you won’t be miserable doing. Feeling a greater sense of purpose will make you happier in your career. Overall, I want to set my students up for success in their lives. Every semester, I hope they’ll walk out of the class and know how an electric vehicle works, their ins and outs, and why they are used.
Car Innovation: What Needs to Happen to Make EVs More Practical and AI’s Role
The following conversation is with Todd Lassa, Detroit Bureau Chief, Automobile Magazine, and Formula 1 enthusiast who researches, reports, and writes about emerging auto technologies for the publication. In this post you’ll learn about battery technology complexities, when EVs could overtake combustion engines, what the future may hold for autonomous vehicles, and AI’s role. Jack: How did you get into merging your interest in autos and writing? Todd: I’m a journalist by trade and come from a hard news background. However, I didn’t get into car magazines until well into my 30’s. I worked for a newsletter company in D.C. covering advanced nursing issues, Capitol Hill and health reform, then began working for AutoWeek in 1996. My core reading audience changed from female to male readers and even having always been a car guy, I had no engineering skills to speak of. Through this transition, I realized that writing and reporting for a living is what I wanted to do. I think I started out wanting to write for a car magazine and then it actually happened by accident. A former co-worker passed my resume to the former Editor of AutoWeek and I got the job where I worked for them for four years, then Motor Trend for 12 years and now write for Automobile writing car reviews and breaking news. Jack: Have you driven many electric vehicles? Todd: Yes, quite a few. The MINI Cooper electric vehicle was one of the first I drove in 2007 or so, which probably barely had a 100-mile range. Fortunately, EVs have changed quite a bit. I have driven Teslas including the Model S which we previously voted in as car of year in Motor Trend. We also named the Chevy Volt car of the year when I was at Motor Trend in 2011. I’ve driven a few Nissan LEAFs and had the convenience of plugging them in here at work. Jack: When I turn off the car heater in my EV, it impacts the car. I think it has to do with the chemistry of the battery. What do you think? Todd: Yes, I agree. Jack: I own an EV, but EVs are more expensive than similarly equipped gasoline powered cars. At what point do you see the cost equation working for EVs so that they overtake internal combustion cars? Todd: When cost, range, and the speed in recharging the EV all improve, that will be the ticket. Recently GM previewed their EVs; they’re building 20 between now and 2023 and some are additions to their announcement a few years ago. One was badged an Escalade and could supplement or eventually replace the ICE-powered Escalade just redesigned for 2021. I think gas and diesel engines will carry them forward for the next decade or so and that they’ll “ramp down” combustion engines as new EVs replace ICE models. GM says this new battery design comes in stacks of 6, 8, 10, and 12 and can be double stacked for bigger cars like Hummers. They are working to get the cost down from $145 per kW hour to less than $100 per kW hour. GM claims once below $100, they’ll be able to make more of a profit on EVs. I’ve also spoken to Toyota who says at this point if you’re selling an EV for less than $50k you’re not making money. They’re looking beyond battery electric. They’re very interested in hydrogen fuel cells, which are represented in their first and second generation Mirai. It looks like a Lexus, but they’re badging it as a Toyota. All of these vehicles are reducing the cost of the battery, which is one of the major goals – to make money on those cars and trucks and to get them up to a 400-mile range. Also important is to be able to add 100 miles on a level two charge. That’s the good news. The flip side is the Chevy Bolt, and such are affordable for EVs but there is a huge shift in the auto industry that is getting away from affordable new cars. I think that brand new cars, whether a Cadillac, BMW or VW for instance are no longer attainable for the working class. Now a $35k range is affordable in the middle class, like Nissan LEAF for instance, is in the low $30k range. I see the entire industry: diesel, gas, EV, all moving on to more premium cost cars. Jack: There has to be a financing program. 30k is a lot for a middle-class person. Manufacturers are going to have to do a resale program or something of the like to make it affordable. Todd: They’re looking at car subscriptions or car sharing. Even those are huge shifts in the transportation systems. At a global level, people are moving closer to big cities, even more so than 60 years ago. Then the question is, do you want a car in a big city? Manhattan is looking at parts of the city without personal cars. One area in San Francisco just went carless and bike lanes are increasing. Cities are moving away from designing streets around cars, moving to designing around public transit, pedestrians and cyclists. Paris and London are looking at EVs only or banning gas cars completely. Auto makers are trying to figure out car sharing. For instance, maybe an autonomous vehicle drives a 9am commuter to work, and then goes to another customer and takes him or her to work. One car can serve many people in a day. This is very pie in the sky, but the amount of money spent on autonomous vehicles is like an EV and the technology is advancing quickly. All that said, the COVID-19 pandemic may change all of the above, we’ll have to wait and see. Jack: Seems like EV range is an issue with EVs. I get about a 300-mile range out of a full charge on my Chevy Bolt. When it gets down to less than 100 miles, I have to think ahead. Should I plug it