CarBEN EV5 Full Sized Prototype Construction - 5 Seat Electric Car From Scratch

[NeilBlanchard]

I picked up the 1993 Saab 900 that is the donor for the suspension i hope to use in the CarBEN EV5:



It was complicated by the fact it was stuck in reverse - the transmission itself; as even disconnecting the input shaft from the engine failed to get it rolling. It took 1:45 to use a come-along to slide it onto the trailer. And getting it back off the trailer was interesting - we used ling straps tied to a tree and pulled the trailer out from underneath it. We will have to drag it into a better position to get it out the area where the garage addition will be built.

[NeilBlanchard]

Question: is steering by wire legal? If so, are there electric steering racks available?

The reason I ask is that this would make setting up the front suspension much easier. The steering arms on the Saab suspension (like most cars) is behind the center of the wheels. The design of CarBEN make it better to move the driver to the center, and move the seat farther forward, so the driver's feet at slightly ahead of the center of the wheels. The steering column is even farther forward.

This makes the steering linkage much more "interesting". Add to that, I also need to push the front wheel skirts out away from the wheels at sharp steering angles.

Maybe I have to have a chain from the steering column down to a shaft that runs back under the driver's feet to the rack? This might solve both the centering and the offset issue at the same time?

By the way, the Saab came out of reverse when my brother pulled it back into a better position next to the garage; so we will be able to push it around, now.

[freebeard]

Most of the electric racks I've seen are electric assist. Most of the chained steering shafts I've seen have the shafts in parallel.

How are the SAAB tierods arranged? Two sections or three? Compare with these:

https://www.google.com/search?q=drag...ering&tbm=isch



Cowl-mount steering:
https://www.google.com/search?q=cowl...=u&source=univ

[jray3]

Yep, I've only seen electric assist, not pure steer-by-wire. There are some expensive aftermarket kits for electric assist, plus some good OEM salvage now available. I've spent a lot of time turning the electric racks of a Saturn VUE hybrid and the Mitsubishi i-MiEV. Both of those have different merits for a conversion. Then of course there's the old converter's technique of just spinning the hydraulic assist with a dedicated motor. I've driven those with a toggle switch to turn the boost on and off. It felt much better than expected, and boost was only needed during low speed maneuvers. Warning though, turn it on during the middle of a low speed maneuver, and the wheel could be wrenched out of your hands!

[CFECO]

Hi Neil, have you given any thought to Cable Steering? Bare cables running over pulleys have been steering aircraft large and small for decades, and Morse steering cables are used in many boats. They are flexible and enable push pull motion to go in many contorted directions. Just a thought.

[NeilBlanchard]

I am pretty sure the Saab has a rack with a push rod at each end; manual only. The steering column input shaft is on the left side. I had not considered cables.

I am going to have to see how the whole front end fits. The half shafts may each have to be ~7" shorter than stock, so that may be too short for decent angles on the CV and U joints. If I can use the narrower Bridgestone tires (from the i3) then I can possible fit the shortened shafts in the chassis, or the wheels may have to be pushed out and the sides modified.

OR, I have to find a good AC motor(s) that can be set up with the output couplings about 11"-14" apart. The current motor choice is ~20" between the output couplings. The original thought was to have back-to-back direct drive twin motors.

[ME_Andy]

The Cruze and the Volt have electric steering racks.

http://www.buyautoparts.com/autopart...ring_Rack.html

[freebeard]

OR, I have to find a good AC motor(s) that can be set up with the output couplings about 11"-14" apart.

I knew you'd come around:

http://ecomodder.com/forum/showthrea...mgr-29878.html

[NeilBlanchard]

Cool! I don't know if a 50kW motor is going to work well for CarBEN, or not. The i MiEV motor is 49kW, I think. I have never heard of the Toyota MGR before. I am reading through the thread, now.

The Brusa motor I was eying is 160kW AC synchronous, and it is water cooled. And it comes with its own controller.

And I found this on the Google Image search page you posted earlier:



That image is from this web site, that also has a lot of useful steering set ups:

Steering System Overview

I'll have to digest this for a while. The Saab parts have the standard Akerman arms on the back, behind the wheel centers.

[stankoprowski]

If you switched your wheels left for right that would move the steering arms in front of the wheel center. Just a thought.

Stan