Thursday, July 29, 2010
Wednesday, July 28, 2010
After double checking everything to make sure it would fit, I began cutting lengths from a bar of hollow, square cross section steel using our cold saw. I then drilled the mounting holes in them, and handed them over to Pete, our designated daytime welder, to weld together. While he was doing that I cut four small triangles out of steel plate and put a hole in each of them. The idea was to weld the small triangles to the bottom of the trunk, and then bolt the mounting frame onto them. This would allow easy removal of the whole frame while having a small permanent footprint in the car and allowing for the cooling shroud to be easily removed if necessary. Once Pete finished the welding, he hit it with a shiny black paint job, and it was done. It fits perfectly too, have a look.
Friday, July 23, 2010
These past few weeks I've been assigned to rewire the breakout box. Before it was a colossal mess but it did what it was supposed to, it got the car rolling.
This time I designed a much more compact wiring box that also incorporates the relay box and other small circuitry. It has one 0.5" cable that goes from the System Control Unit to the breakout box and it does everything else from there. It uses a d-subminiature as an input with two db-25 and two db-9 outputs. It is completely customizable to allow additional ouputs. It has a large 60 signal breakout board that centralizes all the signals that are going to the drivetrain. All of this is done in an enclosure about the size of just the original relay box.
Saturday, July 17, 2010
So I was driving down the road the other day in my all electric Mercury Milan when a Tesla Roadster pulled up next to me. Feeling a little confident about my car, I challenged the Roadster to a race. Within 4 seconds, I was already at 180 kph! I blew that sorry Tesla out of the water!
That's right, I did it with no fuel. Or battery charge. And I left the parking brake on. And my car was telling me to pull over. It's because I was being too awesome.
What? You think I'm lying? Okay! Okay! You caught me.
The slightly more interesting story is that I have started to integrate the CompactRIO, which I mentioned in my last post, into the car. As a test to see if it was working, I decided to control the car's speedometer and satisfy my need for speed at the same time. The next step is to try to convince the car that everything is okay. I hope to get this done by the end of next week so that the car will be ready for inspection and license plates following soon after.
Things are really starting to come together and I hope that you check back regularly for new posts about our work on electric vehicles.
Thursday, July 15, 2010
The little nuances are important when working with a luxury car (something you don’t think about until you are trying to maintain a luxury vehicle). The Porsche is a completed project that team has worked on in the past. Not only is it a beautiful car, it exhibits electric cars as a viable option. However, it is important that this luxury car look and run like a luxury vehicle. At the beginning of the summer, Pete one of the guys on the team noticed this creaking sound and decided it was creaking due to the suspension (the linkages, shock absorbers, and springs which connect the wheels to the vehicle). The decision was to look at the bushings on the suspension and make sure that they were well oiled.
This doesn’t seem like a big deal, but it can take up a lot of time. It requires moving the car and putting it on the lift. Then, we needed to start taking apart the suspension. This proved to be quite the task, in fact we ended up pulling out penetrating oil in order to disentangle rusted parts. We finally were able to pull the bushings out. We cleaned them thoroughly and spread oil on them. We than began putting all the suspension pieces back into the Porsche.
Good news – We got rid of that creaking sound, and I finally became a grease monkey (or at least I now consider myself in the club).
Wednesday, July 7, 2010
Despite majoring in Course 2, before this summer began I lacked the hands on experience that is associated with such a degree – basic shop training. The first thing I want to post about is how I learned to use this equipment.
In the beginning of the summer, Steven Lam a fellow EVTer was designing and constructing an oil sump. In order to build specific sides of this oil sump he needed to use a milling machine. When Steven was working on it, he took me under his tutelage and taught me how to use the milling machine. By the end of this instruction, I knew how to change the mill bits for the various sizes and types of holes needed to cut into this aluminum and understood how the various planes of the mill worked and how they could be used to finish creating a design.
However, this lesson didn’t even begin to cover everything you need to know to use the milling machine. I needed to gain a lot more knowledge and experience before I could use the machine by myself, without being under some supervision. The options were reading a manual, helping my fellow EVTers machine stuff, and/or attending a machining class. Luckily, our team had a shop training class that weekend. After a 3 hour training on the mill machine, I felt comfortable to use a machine basically by myself (of course, I would still need to appeal to one of the senior members on my team to double check my set-up before I began to mill). In addition to this newfound skill, I also had joint ownership on “EVT bling” with Dianna.
This plug will be the new “regular unleaded” for EV’s. It is being used on the new Nissan Leaf, the Chevy Volt, and even Tesla is likely to take advantage of it. On top of that, charging stations are being built around the country by several companies, most of which will use the J1772. Having a uniform standard is important for large scale production, and is a necessary step if EV’s are to become mainstream.
This may sound great, but here’s the most exciting part: we’re getting our own J1772 port. I have been in contact with Tim Rose, the managing director of REMA EV, a company which makes electric power connections. They have been kind enough to donate the port along with the appropriate connectors, and if all goes well we’ll be getting one for the elEVen very soon and one for the Porsche in a few weeks. When it arrives I will be figuring out a way to install the port where the fuel filler cap used to go, and soon after we will hopefully have a way to charge the elEVen’s batteries.
Thursday, July 1, 2010
EVT has worked a lot with the A123 26650 cells: we've cycled them, rapid-charged them, drilled into them, built packs out of them, all in a few semesters. At the beginning of this summer, we even charged the whole eMoto pack in 11 minutes and 30 seconds! This spring we got a shiny NEW toy: an A123 Prismatic Module.
The A123 prismatics have a much higher energy density than the 26650's and they come in a sweet pack arrangement. We have some single cells that we've been testing, and Lennon and Shane have built a rig to cycle one prismatic 1,500 times at a 6C charge/discharge rate. More updates on that later.
For the past few weeks I've been working on using an Arduino and an MCP2515 chip to talk to the BMS built into the Prismatic Pack. It talks over a CAN network, much like the systems in the Porsche or the elEVen. I've found that using the Arduino allowed me to start communicating in CAN easily in only a day or two, and now I can intelligently talk to the module, polling it for voltage and SOC information and telling it to actively balance itself. In the picture you can see the Arduino board sitting on top of the module, and the cable running over the top that connects the two together. The next step will be to output the battery data to a screen and create a system for talking to multiple packs, like we'll have on the next EVT motorcycle.
Say hello to the newest member of the EVT fleet, a blue Lifan motorcycle. This is the same frame that eMoto was originally converted from, and soon it will hold the above prismatic module and a shiny new motor. Last week Lennon, Randal, and I traveled down to Providence and bought the 2-year-old gas motorcycle from a guy who had never ridden it. When we returned, Randal and I ripped the combustion components and twelve volt system out (the lights and fairings had already been removed) and Will has begun designing a new frame to mount all the electric components. Look out for updates on the new frame and another new addition to our team.