Friday, May 29, 2015

Pumps Mounted and Ready

After a hiccup on the plumbing, the Pierburg pumps are in place.

They are mounted to the frame rail on the passenger side of the motor bay just ahead of the power steering pump. Once again, Robert Juarez has built a little jewel that will be mostly obscured by the motor, accessories, plumbing, and wiring after everything gets installed.

Both catch tanks and pumps are well positioned. Between the 90 degree elbow and a "U" curved hose, the pump inlet will be fed by the catch tank output. Input to the catch tank is through the AN-8 elbow fitting at the top of the tank which will connect to the output of the heat exchanger. 

Here's a closer look at the inlet hose arrangement:

Friday, May 22, 2015

Consolidating Controllers

Stepping into some unknown territory here: With the charger and DC/DC converter mounts looking very elegant on the front of the motor frame, the controllers for those devices need to mounted somewhere close. The signal cables are roughly a foot long, so the passenger side of the framework seems to be the logical place.

You'll recall that the Lear charger and DC/DC converter are both OEM units from a Chevy Volt, and each has a little black box containing a small computer for configuration and control.

This is the charger and you can see the controller to the right. The DC/DC converter has one just like it.

With those devices mounted to the front of the motor, it leaves a very inviting area off to the passenger side where the controllers can be placed and have their cables within reach of the connectors.

Initially thinking I'd somehow tie the two controllers together, everything I tried looked like a cobbled up mess. So here's where we think outside the box(es). What if we combine the two controllers into a single box, one that is waterproof and has nice tabs for mounting? 

So here's the result:

All of the contents of the two black boxes have been transferred into the single gray circuit box with computer boards, gland nuts and USB ports all in one.

The control board, USB, and cables on the left support the charger, the stuff on the right will connect to the DC/DC converter. The one unknown is whether there will be EMI (electro-magnetic interference) issues with them in such close proximity. I have to think that the little black plastic boxes provided little or no shielding, so it shouldn't be any worse.

The USB ports for configuration are on the top for easy access. With the cover in place and the connectors exiting the bottom, it looks very tidy. I may add a terminal strip between the two boards and tie both into a single 12 volt and ground to further reduce the wiring clutter.

Wednesday, May 20, 2015

Palm to Forehead Part Deux

Before anyone calls me on this, I goofed. Again. With malice aforethought. Dumbth knows no bounds.

This was the way I pictured the Pierburg pumps from the last post:

Ever heard it said that "if it looks right, it probably is right"? Well this looked right to me, so when Keith asked if it was a good idea to push coolant under pressure into the catch tank, I glibly said no, the outlet of the pump was the nozzle sticking straight out from the center. Well, a seed of doubt grew into a stately tree of trouble, fertilized by a little Googling on centrifugal pumps. 

I should have known Keith was right - the inlet sucks coolant in the center of the impeller where it gets spun around and forced out the discharge on the side. So this would have to change.

There is limited space available, so reconfiguring the mount plate to stagger the tanks and pumps was not an option. The pumps are supposed to be installed as shown on their sides, so rotating them into a vertical position was also not a good idea.

Robert to the rescue:

A simple 90 degree elbow will get the coolant flowing in the right direction and solves the clearance issue with the inlet hose. 

The output has been rotated so it clears the area as well.

Notice the very clever use of a muffler clamp to secure the pump to the plate. 

A project like this is an exercise in serial engineering problem solving. It's just great having professionals like Robert and Keith on the job. 

Taking Shape

The motor assembly is taking shape and it's really looking good. 

The framework mounted to the front of the motor supports the front of the inverter as well as the charger and DC/DC converter. The rear inverter support will be integrated with the motor to driveshaft adapter. The driveshaft spline part of the coupler is resting on top of the inverter. Once the motor spline side of the coupler gets back from the machine shop we'll be able to size and fabricate the adapter housing.

Here's a detail view of the charger and DC/DC converter mount. Both parts are from a Chevy Volt, so they're OEM quality. Jack Rickard and the team at EVTV have decoded the CAN bus message stream for both devices and built small control modules to set the configuration parameters so they can be customized to work with the Better Place battery pack. I plan to consolidate those controllers and mount them on this side of the charger. Tentative placement for the traction pack connections, GEVCU, and miscellaneous relays would be above the charger in front of the inverter. 

Head-on view shows the orange electrical connectors for the DC/DC converter and charger, also coolant ports for the charger and motor with yellow caps. There will be two coolant loops, one for the inverter and cabin heater, the other for the charger and motor. 

Two coolant loops require two pumps and catch tanks. This apparatus will be mounted to a plate that in turn is mounted to the passenger side of the motor bay. We'll lengthen the hose from the tank to the pump on the left to lower the front pump so its output hose will pass below the rear pump.

The heat exchanger is a dual core Derale unit with a 10" fan. It will be mounted behind the air conditioning condenser.

The precharge resistor and contactor box is mounted in the space formerly occupied by the starter battery, along with the power brake vacuum pump. I still need to find a new home for the 12 volt battery, but for the most part the motor bay configuration is complete.

As soon as the coupler is finished at the machine shop, we can fabricate the motor to drive shaft adapter and get this all finalized and mounted. Stay tuned, good things are happening!

Friday, May 1, 2015

Palm to Forehead

Sometimes we make assumptions that get in the way. In planning for the motor and inverter mounts, I'd always had the cable junction box on the top of the motor. That's the way every product photo shows it. That's the way it was strapped to its pallet as shipped from the factory and the way every other build I had seen using this motor was positioned. It made for some challenges in fitting the inverter and especially in getting the cables on the DMOC 645 to reach all the way to their connection. I'd seen the inverter mounted on its side on the firewall and crosswise over the motor, usually to avoid the extra height of the terminal box. We'd considered mounting it vertically in front of the motor but rejected that idea because the short cable wouldn't reach.

This week I stumbled across this photo of the entire driveline as it was designed and installed in the Ford Transit Connect.

DUH!!! Palm smacks forehead. This thing was designed to have the motor rotated 90 degrees so the junction box is on the side and the cables are sized to route neatly to their terminals. Who'd 'a thunk it!

I knew Robert was working on motor and inverter mounts so I dashed over to Pro Automotive with this photo. Happily Robert hadn't committed welder to steel yet, so we could rethink this without scrapping a bunch of work. Turns out that rotating the motor 90 degrees right interfered with the steering box, but 90 degrees to the left found some open space near the motor mount. Here's what it looks like in that position:

The cables will lose their symmetry but will still reach. The inverter is sitting on a block of wood for test fit, but it can be lowered at the front if need be for hood clearance. I'm pleased with this arrangement.

At the other end of the car, Jack Rickard has said that 80 percent of a build effort is getting the batteries to fit. After that it goes pretty quickly. Robert fabricated a tray for the eight pack of batteries I brought over earlier in the week.

The sheet metal between the seat back and the battery box was a bit flimsy for the weight of the pack, so Robert moved the tray to the rear so it is fully supported by the battery box which is resting on the hefty box section frame supports. It's sitting a bit tall, so the legs will be cut down so it just clears the lower pack. It will leave about two feet of deck space, perfect for stowing my instruments as I head around town for rehearsals and concerts.

There is access to the lower pack terminals through the opening between the tray supports. Once these connections are made, it looks like a perfect location for a small box to contain the charging controller and its associated relays and connections.

The final four pack has been assembled to fit vertically in the space next to the maintenance disconnect, so the battery pack is pretty much complete. It's all in one place, which is convenient, but there is some concern about fore/aft weight balance. I'm remembering the steering situation with the eBugeye and prepared for the fact that I may need to add some ballast to even things out. Visually, the ride height doesn't appear to be too low in the back even though the front is completely empty at this point. There are ways to adjust the ride height by reindexing the torsion bars or adding coil-over shocks, but we'll have to wait until we have everything installed to do that final tuning.