First meeting January 30, 2008.
Organizational meeting. Students met and looked over the CNG conversion kit as well as the electric vehicle. We decided to meet on Friday (2-8-08) at 12:00 noon in the shop area of the ATC to begin the work. Almost 30 students have signed up for the club.
Entry: February 8, 2008.
We took a close look at the frame of the electric car and discussed possible locations for the batteries. It was decided that the engine compartment was not the best location for the batteries simply because of 1) weight distribution factors, 2) it would make servicing the motor difficult and 3) it would not make for a good display vehicle with the battery platform obscuring the inner workings of the car. We determined that the batteries could be located beneath the rear seat of the car where the fuel tank used to be. However, some cutting of the car floor would need to be done in order to fit. We figured out where it needs to be cut and it was decided that the aluminium box that will hold the batteries would need to be built first before any cutting takes place on the car. The battery box will also provide crucial integrity to the frame of the car (since this car has a unibody construction). One student is working on the CAD design and he is also doing some stress-analysis on his home computer to make sure that the design for the battery box will support the weight (the batteries weigh about 400 pounds total) and also hold the car together. One other student said that he could weld the box together in his welding class.
We also removed the electric motor and found that the teeth on the spindle (from the motor) are all chewed up and the coupling device that connects the motor to the transmission is chewed up as well. It would have been a matter of time before the connection snapped. We discussed the possibility of machining a new spindle for the motor, but we would still have the problem of needing a new coupler. It was decided that we would find an old Geo Metro in the junkyard and remove the spindle from the gasoline engine as well as the coupler to the transmission. Then we can weld the new spindle to the old one. The electric motor itself is in pretty good shape. It is not burnt up at all. We might install new brushes just to be safe.
As for the CNG vehicle, we discussed the possibility of removing the gasoline tank to make room for the CNG cylinder. A point was brought up regarding the restrictions on CNG cylinder placement. We will need to research these laws. We are hoping to have a CNG technician come and give us a short workshop on CNG conversions. The date for this workshop is yet to be determined.
Next meeting time: Friday 2-15-08 at 12:00 noon in the shop area. Directions below.
Meetings held February 15, 22, 29, March 7, 12 and 19, 2008.
Entry: February 22, 2008
Bill Levitt of the Blue Water Transit Commission came by SC4 to talk to the students about the CNG conversion kit and was able to answer many student questions. Bill stayed for about 90 minutes even though he had very pressing issues to take care of back at his office. Much thanks to Bill for giving us his time.
Entry: March 20, 2008
The battery box has been mounted just behind the front seats. We have bolted the battery box to the floor and also bolted the lid of the battery box to the bottom. There are five batteries in the battery box (about 400 lbs.) and they won't be moving anywhere. This car could flip over and the batteries will remain in place.
The small electric motor that was on this car in February has a badly damaged spindle. After speaking with numerous tool & die shops around Port Huron as well as several electric motor repair shops, the concensus seems to be that this motor won't last very long. The spindle is too far gone and will soon break off. One idea is to add some welding material to the weakest spots on the spindle to beef it up. Then we can machine a key slot into the shaft and attach a lovejoy jaw coupler to it. Anne Vought is planning to do the work on this. We hope to avoid melting any of the internal compenents while performing these welds.
Meanwhile, the folks at Blue Water Lift Truck took one look at this old motor and they just shook their heads. They decided to give me one of the old electric motors that they had in a forklift that was sitting out back-- they were planning to scrap the whole forklift anyway. This is a Caterpillar DC electric motor and it is much bigger than the motor we have been working with. It will be a tight fit to get this motor mounted between the transmission and the passenger side fender. But we can do it. I purchased a jaw coupler that will fit the Caterpillar spindle (1-3/8"). The other side will fit nicely over our splined fitting that fits the transmission spindle. We should be all set.
On Wednesday (3-19-08), we wired up the batteries in series so that we now have a total of 40 volts (5 x 8-volt batteries). We powered up the Caterpillar electric motor with these batteries and the test was a success. We sparked the motor for just an instant and it spun freely for about 20 seconds.
At this stage, we are working to get both motors operational. The plan is to move forward with both motors so that we can experiment with actual driving conditions and compare acceleration, performance and range with both motors. Whichever motor is ready first is the one that we will install first.
In communicating with numerous tool & die shops and electric motor experts in Port Huron, I am overwhelmed with the amount of talent that we have in this town. An engineer can build anything he/she wants in this town and do it quickly while working with very friendly people. I am also finding that most of these talented people around town learned what they know by starting out at SC4. The Engineering Technology Department and the Math-Science Department at SC4 are indispensible strongholds in St. Clair County. As the economy in Michigan shifts from the manufacturing of automobiles to the fabricating of renewable energy devices, SC4 will be right on track to continue its legacy in cultivating the crucial skills needed to spur new innovation in St. Clair County.
Directions to the Engineering Club Meetings: Go to the SC4 bookstore and continue down the long hallway (heading north). Look for hand-written signs (that day only) pointing down a somewhat hidden hallway on the left. The shop area is all the way down this hallway on the right.