Motor Vibration Evaluation

Everybody asks what the motor and everything looks like, so here's a picture of it.

Pete and Tyler pulled the two halves apart and found some nasty surprises inside. Many thanks to the Formula SAE guys who helped us figure out what's wrong. There's a laundry list:

There's a gouge going 3/4 of the way around the inside of the bell housing from the gear teeth on the flywheel. There's hardly any clearance on the flywheel within the bell housing. There's also concern that the needle bearing on the flywheel doesn't sit far enough on the transmission shaft. There's some debate as to weather this is the stock clutch or if these could be due to the previous owner squeezing a larger clutch in there for racing.

There's a chamfer on the flywheel where it mates to the motor, while the mount has no chamfer there, causing the actual mating surfaces to not actually touch.

The countersinks in the adapter ring were so shallow that the tops of the bolts made marks in the adapter plate. The bolts also went into the motor housing only about 1.5 threads!

Pete, Tyler, and Mike worked on deepening the counterbores on the adapter ring, and added a chamfer on the flywheel mount.

Wednesday June 10th, 2009

Today the elEVen team focused on safety and writing up the safety guidelines that they will be presenting. The Porsche team continued working towards aligning the transmission.

Eleven Team Member Highlights: Safety and batteries.

Radu sent out a proposed budget to The Edgerton center and the team. He got the full battery shipment and they are now in the N51 lab. He spent the rest of the day setting up for the Edgerton safety presentation.

Kevin has been writing up safety documentation for the motor and motor controller. Additionally, he worked on writing up documentation to safely disassemble the Fusion.

Matt helped move the battery shipment. He also worked on writing up general shop safety guidelines.

Arya worked on writing up the teams daily procedures in preparation for the Edgerton safety presentation.

Mike worked on writing up battery safety guidelines and dealing with the cells. He looked into regulations for safety equipment needed for dealing with certain voltages.

The Porsche team continued working on aligning the transmission. Today, they were able to safely remove the transmission and motor from underneath the car.

Finally got it out.

Porsche Moved, Motor, Transmission, and Brake issues

Progress has been moving at a fast clip this week so far. Monday we managed to fix the "regen issue". The trouble was that when regenerative braking was turned on, the motor would mysteriously die when you hit the accelerator hard, and you'd have to take your foot off the pedal for a second for it to reset. It turned out to be two current parameters that needed to be dialed down from 400A to 370A.

After that, we moved the car to the N51 lab, where the elEVen will eventually be built, once the Fusion arrives (expected next week). We put the car up on jack stands and took the wheels off so we could start working on the drivetrain issues.

The first issue we're having is that the flywheel seems to be imbalanced or misaligned. The symptoms we're having are major vibrations starting around 2000 rpm and becoming so strong past 3000 rpm that the car is uncomfortable to drive (hence the lack of motor data past 3000 rpm). An additional symptom is that when the motor is spinning slowly, we can hear a rubbing or squeaking sound coming from the transmission that pulses (seeming to indicate it only rubs for part of each revolution). We decided to proceed and drop the motor/transmission assembly out of the car so we can separate them and get them properly aligned.

The second issue is that the rear brakes are rubbing. The left side rubs all the time, while the right side rubs for half a revolution, and spins freely the rest of the way around. We're having Kevin look at it sometime this week since he's worked with brakes before.

Tuesday June 9th, 2009 Update

To date five of the six core members of the elEVen team have been focusing on separate projects that are all key components of making the elEVen come together. Working in the N51 lab today was Mike, Arya, Kevin, Matt and Radu. The team’s 6th member Paul Karplus will soon be joining the rest of the cohort.

Below each member gives a snap shot of the work they have been doing to date.

Radu

At this stage of the project, Radu’s primary focus has been making sure everything is geared up and ready to run by the time the Fusion arrives next week. A batch of A123 cells arrived yesterday and he is working on getting the rest delivered to the shop.

Kevin

Kevin is working on a cooling system for motor and controller. The system will be oil cooled. So far he has found a suitable pump, motor, and filters. It has been difficult because the cooling system specs are for a bus and thus the system might be a bit oversized for the fusion. Later this week he will put together the motor controller and get it spinning.

Matt

Matt is trying to design a drive train for vehicle. He has been focused on finding the drive train components which give best reduction ratio. He is researching three possible options:

1) Utilize existing off-road differential

2) Design our own gearbox and use that in addition to a standard differential

3) Find a gear box that gives the right reduction with standard differential

He is currently researching the components.

Arya

Arya is working on a crucial part of this project: sponsorship. He has been working hard on finding and contacting people who could be potential sponsors for the project.

Mike

Today Mike set up test cells for working with the batteries. He set up a charger that monitors current, voltage, and temperature. The charger was tested with regular double A rechargeable nickel-cadmium batteries to make sure things were working. He is also hoping to rapidly charge some of the A123 batteries today.

Other Highlights:

The Porsche has been moved into the N51 lab until the Fusion arrives. The Porsche team has been working on re-aligning the transmission and will soon continue working on the wiring project.

Monday June 8th, 2009 Update

The shop underwent an atomic clean up. Walls were scrubbed, floors were scrubbed, and tools were organized. No surfaces under 10 ft high was left untouched. In addition, the floor plan was set up to gear up for the arrival of the auto lift (arrival and installation later this week). The shop will be fully setup to house the Fusion in a couple of days. Check out the before and after images.

Before Cleaning

After Cleaning

Other Highlights

Its official. THE FORD FUSION DONATION IS NOW APPROVED. Senior members of the team have been delegated to make the trip to Michigan and drive the car back to MIT. This will be the teams first road trip in the making...

On a more technical note:

• 100 A123 cells arrived today. Testing of heat rise during 6C charge rate will begin (will be formally written up).
• Currently working on BMS plan with A123 systems and an independent manufacturer (MetricMind)
• In the process of drafting plan for Wiring up the motor system, connecting the computer interface, and spinning the motor.

Commencement

A big day in the life of every MIT student (and their parents)... commencement. We didn't have too much attrition by graduation this semester, but that is coming soon enough. Fortunately each new semester also brings fresh new faces to the team.

We worked hard Thursday to get the Porsche looking its best and get the tabletop regen demo working. The Porsche got a wax and a good wheel cleaning. Pictured with the Porsche here is Lennon's electric motorcycle (http://www.electricmotion.org/)

Outreach Demo Work

Shane and I worked on the electronics and wiring of the outreach demo. The demo is a tabletop demonstration of regenerative braking, using a DC motor and flywheel controlled by an accelerator pedal. First we used Shane's TI-based microcontroller board, but eventually switched to a PIC. We also took the ammeter and shunt from the original Porsche conversion kit (which we're not using) for visual feedback on the current flow. In the lefthand picture, you can see the Edgerton electronics lab set up while we were testing and troubleshooting it. On the right, you can see the (almost) completed electronics panel. At the same time, the Porsche UROP crew was building the enclosure for the flywheel and the main display console.

Here's a picture of something we found humorous in the original wiring of the demo. Can you tell what it is?