I see announcements once in a while about some new EV thing, and when I google it, every EV news outlet just has a copy/paste of the same info over and over. I think this particular motorcycle is very newsworthy, and I decided to see if I could find out some of the details, and here is what I found…
_________________________________________________
A review of Ducati history
The Italian company Ducati is famous for two things. Winning races with advanced tech, and…not making a profit selling road bikes to the public. So, lets start at the beginning.
They are based in the city of Bologna, in northern Italy. This was useful to them, because one of the things Bologna was famous for was their university. Believe it or not, the university was founded in 1088, so that was on the leading edge of every new engineering field. Just after the first world war, the Ducati family formed a small company to make radio components. Their electronics factory was eventually destroyed in WWII, and to survive after the war, they decided to buy small motor kits from “Cucciolo” [*Puppy] and attach them to bicycles, which were desperately needed, since many Europeans could not afford a car at the time.
In 1949, Ducati began manufacturing small motorcycles under their own name, with their first model having only 48cc and getting roughly 180 MPG. Many regions did not require a license or registration for such a small engine, and as popular as these small motorcycles were across Europe at the time, the first Ducati could only reach 40-MPH (64 k/mh). Ducati immediately began producing a “sport” model that had 60cc for slightly more power.
In 1953, Ducati split-off its successful electronics business so the struggling motorcycle company would not hurt their survival, if it was forced to file for bankruptcy. In spite of their reputation for innovations, their financial survival would be a recurring theme. Government assistance would help them modernize the factory in 1954, and Ducati earned a major success by developing the fastest 250cc race motorcycle in 1964, the “Mach-1”. The road-going version (Diana Mark 3 Super Sport) was able to attain 100-MPH with only 250cc, and the trend in Europe was for larger engines to have amore expensive registration, so the 250cc class was very popular with young adults.
The name of Ducati achieved its fame from the “Desmodromic” valvetrain that they designed and patented. They began producing 750cc V-twin engines with the desmo valves in 1973. One way to get more power from the same size of engine was to figure out a way to get it to run at a higher RPM. Once the size of the valves are as large as can fit (to allow the best possible breathing), a cam opens the valve, but typically a coil-spring is usually used to close it.
The problem is that once an engine runs up to a very high RPM, the spring may not return the valve to the closed position fast enough. The Desmo system has one cam to open the valve, and another cam to close it, which allowed a much higher 15,000 RPM, compared the their previous 10,000-RPM.
The pic above is the type of sport bike that allowed Ducati to achieve world fame. It was an air-cooled V-twin 750cc, with a 90-degree spacing. The engine was a stressed member of the frame, which allowed the frame to be slightly lighter. The frame also used many small tubes in a lattice pattern instead of using fewer large tubes. This was an inspiration taken from the aircraft industry. This style was more expensive to build, but resulted in a very strong frame that was also light.
Over the years, Ducati increased displacement resulting in the famous 998, they also adopted liquid-cooling, and they even developed the Panagale engine that was a V4 using 1103cc.
All of these things polished the Ducati name for their engineering prowess, but financial profits eluded their balance sheet. They were purchased by Cagiva in 1985, and then by TPG in 1998. In 2005 it was bought by the Italian firm Investindustrial Holdings.
In 2012, Ducati was purchased by Lamborghini, which is owned by Audi, which is owned by the huge global powerhouse VW. The director of VW at the time was Ferdinand Piëch, who was also a motorcycle enthusiast, and many commentators at the time said that the purchase seemed to be more of a vanity purchase rather than a smart business deal.
However, VW has deep pockets, and even if they built an entirely new factory that created new designs that shared nothing with the historic Ducati’s, the Ducati badge gives them a sport motorcycle in their stable, and I think Ducati has finally found it’s home…
_________________________________________________
Why now?
There are three electric racing series that are sanctioned by global governing bodies. The FIA’s Formula E, the FIA’s Extreme E, and the FIM’s MotoE. Since the beginning of the MotoE series in 2019, Energica has been the sole supplier of the electric spec motorcycles. In 2023, Ducati will be the supplier of the MotoE race motorcycles. In a spec race, all of the motorcycles are identical, and the race is a test of the riders.
_________________________________________________
The Motor and Inverter
Unfortunately, Ducati has not revealed who the supplier of the motor and controller is. I suspect the motor is from Borg Warner, and the inverter from Cascadia Motion, but I have no evidence of this, and VW is certainly large enough to have developed their own. They have been making electric cars for several years, from the 2013 eGolf to the advanced 2018 Pikes Peak racer. The rapid development timeline suggested to me that they used an off-the-shelf pair to speed development.
This is the only pic I could find of the inverter. When I find more details, I will post them here. The motor is listed as being able to run up to 18,000-RPM’s. It is most certainly an inrunner, with the outer stator being easier to liquid-cool. Liquid-cooling may seem to add un-necessary weight and complexity, but it allows for much higher temporary peak amps during acceleration. This allows the bike to achieve “X” power levels with the smallest possible motor.
Early in the design process, Ducati engineers had narrowed down their choices to two designs. One was heavier but provided more power, the other was lighter but had less power. They chose to use the lower weight version, because it not only helps acceleration, it also helps braking and cornering too. There is a certain point in the choice of increasing the power where additional power does not help you win races, once you begin exceeding the traction of the design. Burnouts are impressive to the fans, but once the tire breaks loose, you are no longer accelerating.
Ducati is building suspense by taking a long time to reveal pics and details, and the two pics above are the best I could find. They are both liquid-cooled, and surprisingly, Ducati has decided to use two separate cooling systems. One for the battery, and a separate one for the motor plus inverter.
The only detail I’ve found concerning the inverter is that they said they are using the latest design of silicon carbide MOSFET’s
_________________________________________________
The Battery
The big news is that they are using 806V, which allows the wiring harness, inverter, and motor to be lighter. In their street EV designs, Europe is leaning towards higher voltages because the public charging stations are limited by the amount of amps that are available, so higher volts translates into faster charging times.
That sounds good, but Zero motorcycles in the USA has opted for 103V / 28S to make the BMS simpler and more reliable. I’ve been told this is also why Tesla opted for a range of 400V, instead of using near 800V.
One of the things the battery box showcases is their extensive use of carbon fiber, to save weight where-ever it was possible. In fact, the battery case is a stressed member of the frame, so the remaining aluminum frame members can be slightly lighter.
I had a hard time finding information about the electrical system, and here is what I was able to dig up. The pack is 1152 cylindrical cells in the 21700 format (21mm diameter, 70mm long), and it is configured as 192 cells in series, with the parallel strings having only 6 cells (192S / 6P). When fully-charged to 4.2V per cell, the packs max voltage is 806V.
The specs list the capacity at 27-Ah for a total of 18kWH, which doesn’t seem like much. However the MotoE competition only runs a few laps. The cell they are using is the Molicel INR-21700-P45B, which is listed by Molicel as 45A coming from 4500-mAh each, with a low-enough resistance that it has a 3C charging rate. E-One Moli Energy Ltd has a facility in Maple Ridge, British Columbia, Canada. It also has a facility in Taipei, Taiwan.
Pulling 6P x 45A = 270A from six cells is asking a lot, and I suspect the buses that connect the cells are laser-welded copper, possibly nickel-plated to provide corrosion protection. The design team specified that although flat pouch cells might have had less wasted airspace between the cells, it would also have forced them to have a much boxier shape, and using many smaller cells allowed them to have a more custom shape to the pack.
_________________________________________________
Competition improves the breed, and I think this is a good thing. The factory riders said they had to slightly change their riding style because the electric Ducati had more wheel-torque than the gas version when coming out of curves, and the torque was available instantly. However, it doesn’t have as much range and of course the gasoline motorcycles could be re-fueled rapidly.
Even so, I’ve ridden a Zero-S, and I found the wheel-torque to be similar to a 600cc sport-bike, in spite of it’s modest listed 46-HP. Because of this, the “horsepower” numbers of any electric motorcycle are misleadingly lower that what’s posted for gasoline bikes. The place where EV’s really dominate is taking off from a dead stop, and note that the Zero-S has 78 ft-lb (106 Nm) of torque. Gassers don’t want to compete that way, because after the light turns green, they usually end up staring at your tail-lights…
_________________________________________________
Written by Ron/spinningmagnets, August 2022
Source link
