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Next Generation of Electric Motorcycle Design

Thu, 07/18/2013 - 4:04pm
Chris Fox, Managing Editor

Parker and Brammo work together on the next generation of electric motorcycle design.

Collaborative engineering has become more vital now than ever, as companies are learning what they do best and are looking to others to help perfect a product. Brammo, an electric motorcycle company, did just that when they started development on what they hoped would be the fastest electric cycle in the world. Brammo started producing gas-powered, four-wheeled performance vehicles in 2002, but transitioned to electric motorcycles in 2007. The company has since partnered with Parker, an engine systems and technologies designer, to continuously refine their bike, and move to the top of their class with the world's fastest production electric motorcycle.

Designing, Prototyping & Collaboration

Like many motorsports designers, Brammo uses its racing bikes to test new and innovative designs for production models. Brian Wismann, Director of Product Development for Brammo, explains, “We use this race bike not only as a racing machine, but also as a development platform for Brammo’s technologies. That’s why a partnership with Parker made so much sense; because they were looking to develop a line of motors for traction vehicles and electric vehicles, and we were looking to develop technologies for our electric vehicles.” Brammo raced the new electric bike design at the Isle of Man Race in 2009, where they finished as the top American team. “We then took what we learned and applied it to make an even faster bike.”

All of Brammo’s design and prototyping efforts start in CAD, and lead to many iterations with 3D printing, SLA, and SLS models. “Every nut, bolt, washer, and wire on the bike is digitally modeled,” explains Wismann. “In the case of this [Parker] motor, we also used the race program to work through what you would call fully functional and working prototypes, which actually raced on the bikes.”

Parker has a standard magnetics package and a standard mechanical package associated with their motors. In Brammo’s case, the mechanical package wasn’t able to fit the specs that the company needed for racing, so Parker offered Brammo a kit variant, which consisted of just the magnetics. The cycle company then optimized and designed the mechanical package to fit the vehicle.

The design went through five major iterations in less than three years, most of which involved collaboration on motor changes between Brammo and Parker. As the motor development took place the engineers realized the vitality of their temperature management and recognized the need for a robust cooling system. “In this situation, you have two options: Either you can put a bigger, more expensive motor on the vehicle, or you can come up with a very elegant cooling design with an efficient motor that can do the same continuous power within a smaller, lighter package,” explains Wismann. “We have, in conjunction with Parker, designed a couple of different proprietary cooling options that we run on the motor, so the goal is to pull as much heat out as possible.”

As with most things in design engineering, a performance gain in one area leads to a weakness or fault exposure in another. A more efficient motor was smaller, but more susceptible to heat; whereas, a larger motor was more robust, but had a package size that wasn’t conducive to the bike. “I think that was the real benefit of working with Parker as it applies to our production bikes. It pushed a smaller, lighter, more efficient motor package than what we could do conventionally,” says Wismann.

Batteries and energy storage are key elements in the design process of any electric vehicle. The power supply design not only factors in the shape and weight of a vehicle, but also the method o f changing iterations. “In the past, if you thought about designing a vehicle with a conventional gas engine, the thought usually goes, 'let’s keep the chassis as similar as possible between platforms.' But for electric vehicles, it’s actually easier to redesign the chassis than it is to redesign the battery system,” explains Wismann. “So much effort goes into validating the battery design, safety, capacity, and longevity, that once you’ve made that investment into the battery system, it’s almost easier to fit the vehicle around it. That’s definitely been a change in thought process.” 

The Brammo engineering staff used the racing team as a critical part of the prototyping process. “The pure-prototype race bike is different from our production bike, but the goal was always to achieve a performance [in our production bike] that would really make people interested in electric motorcycles,” Wismann adds.

Hands-On Engineer Involvement 

Brammo approaches the racing team differently than tradition OEM designers. The engineers have hands-on involvement in both the racing team and the production cycles. “If you go to a lot of internal combustion engine companies, OEMs that have race teams, either the race team is a separate entity or it’s actually a contracted role for the team,” says Wismann. “So they go out and hire a professional team that runs the race program, and it works out well in that industry because the technology is already pretty well developed. There isn't a ton of development that happens over the course of a season, and you can see that in the race results where they’re chasing tenths of a second per lap.” 

The company sees direct correlation between the success of their race team and the improvement of the production design. “We’ve been through at least three big iterations of motor design and that includes a magnetics, mechanical, and cooling package. So by the time we got ready to develop the production motor, we had a pretty clear view of what was going to work,” says Wismann. The technology evolves so rapidly in the world of electric vehicles that Brammo felt the need to have core engineers involved with the race team. “Last year, from the first race to the last race, there was a ten second per lap difference in the performance of the bike, which is just a huge margin,” says Wismann, “It’s something that you hardly ever see over the course of a season in any form of racing. That result is a testament to having the engineers directly involved.”

Wismann explains that once the engineers see and understand a problem, they can go after it directly, and that allows for qualified rapid changes to the bike for improved performance. “Now, this process is very stressful for the engineering group.” On-the-fly engineering can be tiring to the team, and, at times, even distracting. “For us, it works out great, and the level of enthusiasm we have for the race program is very high within the company,” says Wismann.

A Cyclical Relationship

Brammo started with a performance goal on the race track, which was to get the bike to go faster during the events, and then started solving the technical challenges as they went. The engineering team started realizing that the racing motor applied to the production bikes in terms of not only magnetic design, but also, the cooling capacity. Wismann explains, “When we were running these bikes on the racetrack, the motor and the whole drive train got very hot because of the continuous power requirement was so close to the peak power ability of the motor. What we saw on the production bikes was a very similar scenario.”

As Parker and Brammo continue to work together on the design of these electric bikes, “It’s difficult to explain where Brammo stops and Parker begins, because it is such a collaborative effort,” says Wismann. The Brammo cycles continue to gain speed, and stand as a testimony to the importance of collaborative engineering.

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