Saturday, March 22, 2014

Porsche: Inspection

Ahh...the beginning of Spring Break here at MIT. Only about half of the regulars were here, but it made it much easier to get a concentrated project completed. With the new plates in hand, Joey and Jacob took over putting on the new plates while I stuck my head below the dashboard to try to figure out which wires were headed from the washer switch to the front compartment. Roberto went in search of tubing and taking care of the fittings for the water side of the windshield washer.

We traced the wires to the front of the vehicle, and not surprisingly to the windshield wiper motor. There was only one and it was connected to each wiper with a 4-bar linkage.
The electrical connections for the wiper motor. I thought there would be fewer wires.


The washer pump went in easily enough, but we had to improvise on the washer reservoir. The reservoir we purchased would have required extra fittings, and we were running out of time; so we used a water bottle and went off to the inspection station. As we drove, I wonder how far we had come from the previous group which used a pressurized bottle for the reservoir.



Into the inspection station. Note the EV license plate.
As we got to the inspection station, we failed almost immediately. Something happened between the time I shut down the vehicle in the parking spot, and turning it back on a few minutes later. The horn, signals, lights, and windshield wipers didn't work at all. It was like they weren't getting power. Heads hung low, we drove back to the shop and started brainstorming what happened.

After 45 minutes, we decided to check the low voltage fuses, and found one that was most definitely blown. I posted in July about fuses, and I should have recognized the symptoms earlier. I still don't know why there were so many systems drawing from that one fuse.
Most definitely blown, but an easy fix.
After changing the fuse, we set off again. Since the inspection station wanted the last car to be in by 5 pm, and closed at 6 pm; we were able to fit in at 5:20 since we were there earlier.

This time we passed, with the only closing note being that we should change our wiper blades since the blades were smearing rather than clearing.

On the way back to the shop, we stopped and I asked a good friend (Kaitlin) if she could take a picture since we were the only three still around the shop at the time. Michelle (in the background) is an alum who helps to provide some sanity to all the nutty things that Roberto and I dream up.

Success!

With the title, registration, and inspection in hand, this process began with a thought in June 2013 and work began in July 2013. I can't thank the team enough for keeping me going to press through with getting this process done. The Mechanical Engineering department gave us some much needed help to help us climb Mt. Washington in September 2013, and that experience helped us to build the camaraderie and team skills we needed to make progress through the fall and to this point. Last but certainly not least, I would like to thank Sandra Lipnoski from the Edgerton Center, for helping me through the administrative process, and always reminding me to make copies of important documents.

Monday, March 17, 2014

Porsche: Title and Registration

Since my Finance Theory class was cancelled today, I went to the RMV (Registry of Motor Vehicles) in Chinatown and took care of getting the title and registration for the Porsche. I walking into the RMV at 1:30, and walked out at 5:20. If anyone wants to find a good place for a coffee shop, it is right next to the RMV. Compared to being at MIT, the boredom of sitting at the RMV waiting for hours to be called was excruciating. Alternatively, a recumbent bike attached to a small generator might do wonders for giving folks an outlet and giving kids and antsy college kids something to do.

As always, a smile can go a long way, and I walked out of the RMV with two EV plates in my backpack, and a copy of the interim title/registration. The catch was simply that I had to have to vehicle inspected within 7 days time. No pressure of course.

Saturday, March 1, 2014

Porsche: Windshield Washer

The signals work, we have the title in hand, and the car runs well; however, we still can't pass inspection. The car was shipped from the factory with the windshield washer driving off a pressurized system. To fit the batteries into our Porsche, the spare tire was removed, as was the original windshield reservoir system.

In the past, this obstacle was overcome with a pressurized soda bottle that utilized the same switch from the original car. However, Roberto and I both were not keen on maintaining this system for the future. Our rationale was simple; water and electricity don't mix well, especially high voltage.

To satisfy the requirements for inspection, I followed two different set of directions to build an understanding of what to expect. Since I relied on them heavily in the initial phases, I don't mind posting the links here. However, I should note that not all of the information was completely accurate for our vehicle. I am unsure if this applies to all 1976 Porsche 914s, or just ours, since it has been heavily modified from the stock setup.

PelicanParts Tech Article
ElectroClassic EV

To start off getting down to the wiper switch unit itself, I followed the two links and removed the horn assembly, and steering wheel.

Getting closer to the windshield switch. I drew the line on the column there to help with reassembly later. The copper lines and surface seen around the column there is part of the turn signal assembly.

Here is the mount for the steering wheel, note the 6 (six) smaller screws that would match the six hex head bolts of the steering wheel. There was a matching mark on the mount to help with alignment later.
I didn't take any more pictures, but the after-market replacement unit was simple enough to fit in without having to shave down or adjust the male end of the plug as the posted website instructions had mentioned.

Saturday, February 15, 2014

Porsche Title

As we are trying to get the Porsche street registered again, we were able to acquire the Title in the name of MIT and we can begin moving forward with registration and inspection. This also means that any injury related to the vehicle is now in MIT's name, which is much better than in a single person's name.


Now on the To-Do list is to retrofit the windshield washer system from the original configuration, which utilized the air pressure from the spare tire, to a modern-electric motor driven system. Parts are on the bench as we type.

Saturday, February 8, 2014

Porsche Signals

The other weekend, we started working through some issues we were having with the signal lights on the Porsche. We were having issues where the individual signals would only turn on when the stalk was moved in a direction, and the hazards would flash once or twice and then stop responding.

Low voltage electrical relays. Picture taken from driver's seat.

As we delved deeper into the vehicle, we remembered that the vehicle is 38 years old and even though it came to us in good condition, it is hard to stop the aging of the electrical terminals.

Note the coloring of the contacts.


The signal/hazard relay is the square box located on the bottom of the picture. We thought our signal issue was an issue with the signal relay, and we found a replacement online. It should be a plug and play type of situation. Right out of the box, we noticed that the original was significantly heavier in weight, and about 80% of the size of the original.

Original on left, replacement on right.

The replacement relay physically fit quite well, and we powered up the low voltage to test out the system. Interestingly, the signals would flash very slowly (~2 seconds on, ~2 seconds off). The hazards also had a different frequency. While this might satisfy the Massachusetts state inspection, we were concerned that it wasn't fast enough to catch another vehicle operator's eye.

After scratching our heads for quite a while, we remembered that the signal lights were replaced with LED lights a few years back. LEDs (Light Emitting Diodes) consume much less power, and are great for a variety of applications. About the only environment that has had some difficulty adapting to LEDs is the traffic light and runway light environments. Since LEDs produce so much less heat than conventional lighting sources, ice can build up on these surfaces and either block the light or change the light refracting properties of the lens such that the effectiveness of the lights are diminshed.

For us however, if we applied the RC Circuit concept to the system, the change in the headlight source may have been changing the dynamics for which the relay was designed to switch with. Thus, we switched back to the original relay and used the opportunity to take a look inside.



The relay is simple in concept, relying on the magnetic field created by an applied voltage to close another set of contacts and close the circuit. A solid state relay is traditionally viewed as being more energy efficient since it does not require the currents needed to hold the contact closed. For reference, efficiency is the output per unit of input. Since the mechanical relay (as shown above) used some energy and arguable produces no work (output), it is seen as a negative efficiency influence. Solid state relays have some pitfalls when used for certain applications though. Feel free to contact us and I should be able to elaborate on this in some detail.

Using a lab bench, the relay worked perfectly fine. However, we noticed it was hard to get a good connection through the 38 years of age. We never considered this as a potential problem being that the contacts should not have moved within the housing, therefore the connection should never have been broken. We were wrong.

Using microgrit sandpaper (CAMI-600 in this case), we sanded down the male ends of the connectors and reinserted the original relay. Everything worked fine, the timing of the hazards/signals were within the expected range (~0.75 sec on/~0.75 sec off), and both the hazards and signals had the same frequency.

For us, this was surely a learning experience in that we shouldn't make assumptions without some verification, and that we should always check our contacts before changing parts.


Saturday, January 25, 2014

IAP Week 3 - maiden crawl

Another extremely productive week at EVT.

Sprocket got machined! Here are some action shots!

the joys of cnc machining


done!

hub fits!
After the sprocket got machined we did a couple of tests with the wheel propped up.



Then it was time to get to the hallway!



woops



Sunday, January 19, 2014

IAP Week 2 - Lots of building!

IAP Week 2 is over and we are on schedule to be able to make a maiden crawl by next Saturday. This week lots of milling, turning, broaching, drilling, deburring, crimping, tapping, brushing, sanding occurred and we are very proud with the results!

waterjetting the alumnium (thanks Javi!)

Broaching the key on the sprocket
sprocket has been keyed!
fitting the bulkhead connectors


looks like the parts fit! time to sand and clean them!
yay! motor fits!
eric and joey making connectors
data connector layout

getting ready to rivet the angle stock to the waterjet plate
erich lining up both pieces carefully
the riveting art of riveting
notice our temporary acrylic sprocket (steel coming soon)

ready to assemble! 
putting in the new stays


looking pretty thus far! (notice the sexy bulkhead connector)
getting the motor in place!
"fully" assembled!! shorter u-bolts and steel sprocket coming soon!


1

starboard side of the trike


rear of the trike!
everyone tweaking the mounts





a video of the motor turning! (tension needs to be adjusted)

jacob on the trike!



woohoo the brake firmware/motor control works! thanks EE team!


in order to get familiar with HSMworks on the EZ track Jacob and Roberto machined a piece of abs with same features that are going to be machined on the steel sprocket this coming week (thanks to Andrew Carlson for the help!)