Exclusive Interview with Chevy Bolt EV Chief Engineer

The 2017 Chevrolet Bolt EV will be available for sale in less than a year. A five seat hatchback with a 200+ mile electric range with a base MSRP of about $37,000. Will the Bolt affect i3 sales?

This week at the North American International Auto Show I had the opportunity to sit down with Chevrolet Bolt EV Chief Engineer Josh Tavel. We covered a variety of topics related to the Bolt EV, which was the cornerstone of the Chevrolet press conference at NAIAS this year. I originally posted this on InsideEVs, but I believe the readers here would also be interested in reading about a potential i3 competitor which is coming to market in less than a year. 

I started out asking Tavel what he felt were some of the biggest challenges his team faced with the Bolt.

Here’s Tavel’s response:

“This is a very different car.” 

“You might expect me to answer this by saying one of the major components like the battery or electric motor, but that really wasn’t the case. We’ve been doing batteries and electric motors for a long time at Chevrolet so they’re known entity for us.”

“The biggest challenges were really because the vehicle architecture of the Bolt is different. It’s the unique packaging of the Bolt which was probably the biggest challenge. It affects everything. Some of the predictive models, the CAE (computer aided engineering) work really well with conventionally powered vehicles, but when you take yourself out of that architecture and apply it to this new type of vehicle, they don’t work that well, so we really had think differently. There were a couple of areas where we had to take a different approach, because this architecture is so different than anything we’ve ever done.”

Talking about crash testing, Tavel stated:

“In crash testing, cars have unique crash test signatures, but the results of the Bolt are unlike any other car. That said we’re feeling really good about us being at the top of the segment from a safety perspective.”

He went on to talk about how they spent time slimming down the front seats in order to give the rear passengers more leg room and save weight, but how that then affects crash testing, and how the battery tray is incorporated into the main structure to increase the stiffness of the chassis.

Regenerative Braking

The Bolt has two driving modes, drive and Low. The regen level in normal mode is minimal, and basically simulates how a conventional car without regenerative braking feels. I specifically asked him to describe how “Drive” mode feels. Tavel explained:

“It’s still in the same field as a normal car. There are normal cars that have as much natural decel as the Bolt in Drive; it’s not out of the norm. Originally it was tuned such that if you were to take 100 people and monitor them coming to a stop light, and monitor that decel, and let’s say it would be about .2g’s. The Bolt was designed for .2g’s – to basically act like a conventional car. But the problem was, sometimes you need a little bit more, and it didn’t give it.”                                                                                                                                                                                                                                                                                                           "So actually just this past December we were all out in LA and I said ‘You know guys, this is stupid. It feels like were making the one pedal driving be kinda acceptable for the people that don’t like it, and kinda acceptable for the people that do. Why are we doing this halfway? If they don’t like it, they have drive (mode), the i3 for instance, doesn’t have a drive mode with light decel. So if they don’t like regen, go to drive. If they want it, give it to them (low mode with heavy regen).’ So now we’re at a spot where I can drive home and never touch the brake pedal.”

In addition to the Low drive setting, the Bolt has a Regen on Demand paddle on the steering wheel. So there are actually four different levels of regen with the level of deceleration getting stronger at each level below:

• Drive mode (mildest regen <.2g’s)
• Drive mode using Regen on Demand paddle
• Low mode
• Low mode plus using Regen on Demand paddle (strongest regen ~.3g’s)

Artificial Creep

In order to come to a complete stop while in Drive mode, the driver will need to use the friction brakes. In these conditions, when they release the friction brakes, the car will creep forward. Artificial creep and whether or not it belongs on an EV has been a highly controversial topic and one debated amongst the plug in community. The Bolt has a unique way of dealing with it. If you don’t like strong regen and use drive mode, the engineers feel you probably like how a conventionally powered car performs and they give you artificial creep.

However, if you like strong regen and use low mode, or stop with using the Regan on Demand paddle, the artificial creep is disengaged. In those circumstances, the car will hold its position there, even if on an incline. There is no need to depress the friction brake. However, if the operator does press the friction brakes after coming to a stop using the regen, and then releases the brake pedal, the car will creep forward.

The Bolt uses the same DC fast charging standard as the i3, the Combo (CCS) system.

DC Fast Charge

With Tesla currently charging at over 100kW, and Audi & BMW talking about the new 150kW system they are working on, I asked Tavel what would be the highest speed of DC Fast charging the Bolt would accept. It’s clear this topic is one that is still being internally discussed, but I also got the feeling it will most likely be limited to what the current hardware in the ground can deliver, that being 50kW.

“We’re still figuring out how fast we want to go. We’ve over validated a lot of our components just in case, but were still figuring out if we want to limit it to say, 50kW’s or 60kW’s or possibly higher. That decision hasn’t been made yet but I can promise it won’t be lower than 50kW.”

Torque Steer

I drove a MINI-E for two and a half years so I know have a front wheel drive EV with lots of torque can feel. The MINI-E was a blast to drive, but under full acceleration I needed to hold the steering wheel tightly with both hands to keep it from jerking from side to side from the torque steer. I wanted to know how the Bolt would feel with 200 hp and 266 lb-ft of torque going to the front wheels.

“We’ve got some special controls in there for that. Our steering system and our EBCM (electronic brake control module) has some pretty slick calibrations in there to combat torque steer. You can feel a little bit of it but I think it feels fine. There’s a lot of power up there so if you were to remove the controls we put in place the torque steer would be pretty wicked.”

Comparing the Bolt to the Volt

I asked Tavel to describe the performance of the Bolt, and possibly compare it to the plug in competition. Unsurprisingly, he chose the Volt as the car he would most closely compare the performance to.

“The Gen 2 Volt I think is a great car. Amazingly, I’d like to say that I believe we’ve worked it out so that performance wise we’re equal to where the Volt is. To me, there is no competitor I wanted the Bolt to be like. I think the Volt, the Gen 2 Volt specifically, is a really well done car. And that is a car we compare ourselves to a lot. 

The Bolt has a traditional-looking gear shifter. Other EV's like the i3, the Model S and the Nissan LEAF have ditched the traditional shifter for something different, since gear shifting really isn't necessary on an EV

Why the traditional gear shifter?

Since electric cars don’t really require a gear shifter, and some manufacturers like BMW, Nissan and Tesla have ventured from the norm of the traditional gear shifter on their electric offerings, I asked why the Bolt has what looks like a gear shifter for a traditional automatic transmission. Tavel was quick to dismiss the need to change what works.

“This isn’t some funky looking car that’s some whizzy statement. This is a mainstream car that happens to be propelled by electrification. It’s not some unique quirky little thing. (I couldn’t help but think he was referring to the BMW i3 here) It’s a real, no kidding, good car. It’s already an electric shifter, if you pull that away the car gets maybe a little more different than you might want, and quite honestly I think there are some questionable safety issues if your reaching up and moving things up there that I don’t think as a company we want to go to right now.”

Side note: Right as I was asking this next question, Carlos Ghosn and his entourage were escorted onto the platform behind us to have a private look at the Bolt on display. I couldn’t hear exactly what they were talking about, but he wasn’t smiling.

No Carbon Fiber?

The Bolt’s press release from GM stated the Bolt incorporated advanced materials including aluminum, magnesium and carbon fiber to help lightweight the vehicle. I asked him if he can explain where these materials were used, and how they helped save weight. Tavel was surprised there was a claim that carbon fiber was used on the Bolt, and in fact told me he believed that was incorrect. As for the use of advanced materials and light weighting, he said:

“We saved just shy of 50lbs by using all aluminum enclosures (all the exterior body panels are aluminum). The underbody is 95% high strength steel or advanced high strength steel, some of it is the first time it’s been used in production so far. The upper body, not counting the exterior panels is about 80% high strength steel, so there is a lot of advanced materials in there, but we didn’t use carbon fiber anywhere I can think of.”

On high tech advanced electronics

With more and more advance electronic features becoming available in today’s cars, I asked if the Bolt would feature any of these technologies. I specifically asked if the Bolt would have adaptive cruise control, lane departure assist, self parking, automatic braking or any autonomous driving features and I was a little surprised to hear it won’t, not even as optional equipment. They will however introduce a few new features that weren’t on my list. Tavel explained:

“No. Adaptive cruise control – no, you would need the blended brakes to do that and we didn’t want to do that with this car. However, all the standard side blind zones, rear cross traffic alert, ten air bags, all that’s there. What’s new is the optional Rear Camera Mirror. You normally have a 22 degree field of vision with a standard mirror, this takes you to 80. We also have optional Surround Vision, which you know is the 360 degree camera system. We’re still working hard to perfect it, but I’m told it’s the best one camera systems the guys have seen so far.”

Conclusion

Overall, I really got the feeling Tavel was extremely proud of the Bolt. He took particular pride in talking about how different this car is from anything GM has ever produced, and that his team worked relentlessly on every small detail to try to achieve perfection. While they are still actively improving things, they are actually pretty close to a finished product.

In fact, he said GM has executive test drives every week, and after some of the top brass drove the Bolt last week, they told Tavel he could release the car now, and as far as they are concerned it’s finished. He’s not satisfied yet though, and that’s what you’d expect from your chief engineer.

BMW i3 Melts Away in House Fire

Believe it or not, this was an i3. Unlike the 328i that was also destroyed in the fire, it's difficult to tell that this pile of burnt material was once a car.

One of two things usually happens when people see an image of an electric vehicle on fire or the remnants of an electric vehicle that had been on fire. If you're an EV supporter, you probably hold your breath and grimace a bit until you can read the article to learn what caused the fire and if anyone was hurt. But for many people who are unfamiliar with electric vehicles, they likely question the safety of EVs. They don't even have to read the article; they just see "EV and fire" together and the unfortunate and uninformed speculation begins.

Luckily, since the recent electric vehicle movement began roughly 6 years ago, there have been very few cases of EV fires, and to my knowledge no one involved has suffered an injury. Other than a couple of incidents involving the defunct Fisker Karma, the causes of EV fires have been mostly a direct result of a severe impact compromising the battery pack. I don't know of any instance where an EV has caught on fire because of a systems failure with the high voltage battery pack or power electronics. In fact, as a comparison a gasoline powered vehicle has a greater chance of having a fire than an EV, statistically speaking.

You can recognize the seat frames, strands of carbon fiber and the optional rear 20" Sport wheel, but not much more

So while I usually don't like to use the words "EV and Fire" in the same story, I found this one particularly interesting and wanted to share it.  For one, I've never seen an i3 after a devastating fire incident, (these are the only pictures of an i3 after a fire that I know of) and two, because of the unique state of the car following the fire. I'd like to first say that thankfully, nobody was hurt in the fire depicted here. Also, neither the car, nor the home charging equipment, had anything to do with the fire. It was an unfortunate accident resulting from a fireworks event for a New Year's Eve celebration last year. Hours after cleaning up the debris from a neighborhood event, a trash can that had ashes from the fireworks ignited. Neighbors had gotten together for the fireworks display and the clean up. There must have been something placed in the trash that wasn't completely extinguished, and after a few hours of smoldering, it unfortunately caught on fire.

A very unfortunate scene 

It's pretty shocking to see how little is left of the i3 after the fire. The plastic body panels and CFRP Life Cell just melted away. Without the steel frame and passenger compartment used in a conventionally built car, there is practically nothing recognizable in the pile of i3 debris after the fire. However once they started cleaning up, they were able to drag the aluminum frame with the battery tray out of the garage with a tow truck. Although you can't tell from the photos, the owner, Tory Johnson told me that the aluminum frame and battery tray were still intact. Tory also said it was interesting to see that while the resin which holds the carbon fiber together had melted away, the actual strands of carbon fiber didn't melt, and were clearly visible after the fire.

The 328i next to the i3 in the garage was also destroyed by the fire, however you can still tell it was once an 328i

It's been over two years since the first i3 was delivered in Germany, and at this time there are about 40,000 i3s in customer hands. It's actually a little surprising that there hasn't been a news story or a picture shared on social media of an i3 that had been involved in a fire after a severe accident, or even one like this, that was just in the wrong place at the wrong time. At least we now know what to expect.

Even after removing the debris and cleaning up the garage floor had clumps of dried CRFP resin where the i3 had basically melted away.

BMW i3 Repair Process Deep Dive

 

Occasionally I cross post content from other websites here (with permission of course) when I think the article is both interesting and exceptionally well done. Such is the case with this post written by Chuck Vossler of BMWBLOG about the repair process of the i3. I think Chuck may have taken particular interest in this story since he recently revealed to me that he has indeed ordered an i3 for his personal use. I have also been talking with him for the past year about his interest in solar electric and am happy to say he has indeed installed a solar array on his home and will soon be joining me in driving his i3 on pure sunshine, or "driving the future" as I like to say. Electric vehicles combined with solar electricity are such a fantastic combination, and adding the second one to your life is such a natural decision to come to once you have the first, as long as it's physically and financially possible to do so.

The entire article and pictures below were written by Chuck Vossler and appeared first on BMWBLOG.

The BMW i3 is truly a revolutionary new car. Revolutionary, however, is not exactly what the repair shop wants to hear when it comes to …

The BMW i3 is truly a revolutionary new car. Revolutionary, however, is not exactly what the repair shop wants to hear when it comes to fixing a totally new car. Never before has any manufacturer made such extensive use of carbon fiber in a mass produced car. One of the main benefits of the Carbon Fiber Reinforced Plastic used in the BMW i3′s Life Module passenger compartment is that it weighs about 50 percent less than traditional steel and also about 30 percent less than aluminum. The Drive Module houses a 22 kWh battery, the chassis and the 170 hp electric motor. Therefore, the new lightweight materials used in the i3 comes with totally new repair processes.


BMWBLOG had the opportunity to tour the BMW North America training facility where technicians for U.S. dealerships come to learn how to repair the very unique lightweight i3. Most consumers won’t really care about the details of how the i3 is repaired but one thing they will care about is what the BMW i3 costs to insure. The more complex and expensive the repair, the higher the insurance premium. A more complicated and challenging service and repair process directly leads to higher ownership costs which will ultimately impact sales.

Fortunately, BMW states that the cost of repairs for the BMW i3 are similar to a BMW 1 Series. This is intriguing given that once a carbon fiber piece is broken, there just is no repairing of it. The entire part/body panel must be replaced. Nonetheless BMW knew the implication of building a car of CFRP and thus designed specific cut away sections in the i3. These are defined segments that when cut will allow the technician to remove the damaged CFRP piece and then bond the new CFRP segment back in with glue.


THE DRIVE AND LIFE MODULES
BMW constructed the i3 in two segments, the Drive Module and the Life Module. The Drive Module contains the electric motor, suspension, lithium ion battery and is the backbone of the car. This module is made mostly of aluminum and its repair process is very similar to other aluminum chassis components that BMW has been producing and repairing for years.

The i3's mostly aluminum Drive Module

The Life Module is the occupant cabin and its backbone is made of Carbon Fiber Reinforced Plastic. This frame and roof are all CFRP where as attached to the sides of the i3 are composite plastic panels. These panels are designed to absorb what would normally dent a metal car and pop back into shape. Added bonus: your i3 isn’t gonna rust.

Aluminum: BMW states that standard “Cold” repair methods for the aluminum components will be used in repair. These include bonding and riveting. These methods have been used by BMW workshops since 2003.

Panels: BMW designed the panels to be replaced via standard screw/clip on plastic plated parts, so not much different really than a standard car.

Glass: The CFRP body which is surrounding and holding the glass can be damaged by a standard glass removal tool, so there is a special tool required here. Overall the mechanism of removing and replacing is similar. Standard glass removal tool uses a strong metal wire that would damage the carbon fiber, so BMW’s tool has something like a super strong fishing line.

Even replacing the glass on an i3 requires a different process and tools

Carbon Fiber Body: This is where repair techniques change significantly from standard cars. There is no pounding out damaged CFRP. In order to repair the i3, the damaged section will need to be cut out at one of the predefined points. These are located at the top of the A, B, C pillars as well as forward and aft of the floor pan.

BMW requires a specialized cutting device that looks part bone saw on the business end and part Dr Who Villain, a Dalek, to vacuum up the carbon fiber particles. Once the carbon fiber body has dis-articulated at the very specific points, the technician then places the new section on and bonds/glues it back together.
This is where my favorite part of the tour came. “This isn’t very complicated but it needs to be very precise,” says a BMW technician. He further added that the time it will take to repair i3 electric vehicles will actually be less than standard cars and thus decreased labor costs with auto repair.

BMWBLOG is happy to report that the insurance cost for the BMW i3 is similar to a 1 Series Coupe. Adding a BMW i3 to my automobile insurance policy will only raise the monthly payment by $42. Take that with a grain of salt as car insurance policies range all over the place depending on driving history, use and location.

The BMW i3 has a 22kWh battery powering a 170 hp electric motor good for an 80 mile range. It has been tested as the most efficient electric car available on the market due to its low weight with extensive use of Carbon Fiber Reinforced Plastic: 124 MPGe. The Range Extended version has a small generator in it which never directly drives the vehicle’s wheels but rather charges the battery while adding roughly 330 lbs to the vehicle curb weight.

BMW i3 Production Delays Reported

Virtually every facet of the i3's manufacturing process is different and BMW is evidently struggling to manage setbacks

According to Jay Cole over at insideevs.com i3 production is currently 50% lower than expected at this point in time. Cole's source is Manager Magazine Online, a German Publication, which states the high rejection rate of the carbon fiber parts made for the car. The article goes on to say that BMW's recent announcement that the company will be investing another 100 million euros to increase the production of carbon fiber is tied to this issue.

Manager also says BMW is only churning out 70 i3's per day which is about half of what they were hoping to be making by now. BMW began i3 production in October so they are four months in and now have over 11,000 i3's on backorder. Plus, US sales are only just beginning so it would appear that even if BMW gets the current problems solved in short order (and that's a big "if"), it will still probably take them nearly a year to catch up with demand since the orders will continue to pile up. It has long been speculated that BMW will have the capacity to make between 30,000 and 40,000 i3's per year once they are running at full production.

It seems we now have some answers to two things which were puzzling US customers recently. A couple months ago BMW announced that US i3's will not have a moonroof available. This comes long after it was announced that the i3's with Giga World and Tera World interiors get the moonroof included with the packages. To make matters worse, most of the i3's here in the US are pre-production European spec cars and they all have sunroofs. So everyone that had the opportunity to test drive an i3 got teased with seeing the moonroof that they were later told they won't be able to have. Then, a few weeks ago BMW announced the first three months of i3 US production would be limited to a "Launch Edition" version. The Launch Edition is fully loaded with every option available on the car and the most expensive Tera World interior. The only thing the customer can choose is the color (and only the metallic colors are available) and if they want the optional 20" sport wheels.

Many people speculated that is was simply a money grab and BMW knew the car would be in high demand so they could get away with making anyone that wanted one of the first i3's in the US buy one that was loaded. Now, with the recent news about production difficulty, I think it's obvious the reasons the moonroof isn't available at launch, and custom ordering isn't available for another three months, is solely because BMW is struggling to refine the manufacturing process and eliminate the problems they are currently having.

I've had the opportunity to talk with many BMW program managers over the past few years. One of the things that has always stood out to me was how on one hand they were really excited about the i3 because of how special and different everything about it is, while on the other hand they would always acknowledge how big a challenge it was going to be. Everything about the i3 is different. BMW has never made a car that required special manufacturing processes for virtually every stage of assembly. Besides the electric powertrain, most of the materials used in the car are even different. While the biggest challenge is likely working with carbon fiber on such a large scale, they are also using more aluminum on a car than they ever have and are using interior materials that they have never worked with before. Then there is the outer thermoplastic body panels which BMW has never used before which has even led to the painting process presenting challenges.

So personally I'm really not surprised by all this. The i3 is a revolutionary new car for BMW, and nobody else is making anything quite like it. Yes, there are some that will look at it and say "It's just another 80 mile electric car, big deal", or "It's nothing more than a Nissan LEAF that costs $50,000". I respect everyone's opinions, and for some people it doesn't represent any more value than a $30,000 Nissan LEAF and that's fine. However when I see the i3 I see the future of the automotive industry and I applaud BMW for taking the enormous risk of building such a radically different car, something that nobody else is attempting to build. Yes, I wish it had more range and I think BMW would have been better served if it could really deliver 100 miles of consistent real world range for most drivers, and it's clear it will not. But that's the biggest knock I can offer and it's far from a deal breaker for me. BMW will get past these initial manufacturing snafu's. The top concern at this point should be quality, which I'm sure it is. The production numbers will increase and by the end of the year I'm sure they will have everything running as smoothly as planned. The question is will the customers wait many months for their i3 to be made? I suppose the people that don't put as much weight on how special it is may not, but those that appreciate how unique the car really is will. After all, there is nothing else out there they can get that is quite like the i3.