Insight 4x4
 

Has anyone considered adding motor(s) to drive the rear wheels of an Insight? This would be a way to add PHEV capability without getting involved with trying to modify the existing Honda engineering. By keeping the rear wheel drive separate, compatibility issues coud be avoided completely.

Kinda close:
Mike's 99mpg e-5th wheeled Insight

Instead of adding motors to the rear wheels, he just added another rear wheel!

Hi, Hugh.

If you're looking for a commercially available RWD donor vehicle, wait for someone to crash a Mitsubishi Imiev. Its battery is fairly small and manageable, too.

Aside from Mike Dabrowski's 5th wheel, there was also Team FourSight from the Automotive X-Prize. They put an EV drivetrain up front, and the diesel engine and tranny out of a euro-market Smart in the rear.

Gentlemen, thank you for your observations and suggestions.

Of course, Mike Dabrowski's ingenious ground breaking E-Wheel is one solution and it shows the way one Etek motor can propel an Insight at about 23 mph. Maybe two (2) Etek motors can get you up to 46 mph or more, especially if the drive is efficiently done through the existing rear wheels rather than an additional wheel.

It is well known that an Insight will travel quite well on 13 HP. Two Etek motors combined develop about 12 HP and up. Mike's work has shown the kind of electrical loads we might expect from this motor in actual driving conditions. Two of these motors on an E-Wheel might work but the placement of a bulkier setup is a problem of finding the room. Locating any where off the rear axle centerline would subject the added wheel to side wear or scrubbing and loss of traction. Driving through the existing wheels has obvious advantages beyond the need for the additional wheel(s) and the need for the retract/extend mechanism.

Belt drives on motorcycles typically are a little over one inch wide and carry considerably more torque than an Etek motor. A conservative estimate of a 3/4 inch wide belt for our final drive fits well within the working range shown on belt drive design tables.

If we allow for 1/8" to 1/4" clearance between belt and tire as do the motorcycle applications, we need to find 1" of space for our final drive. By tightening up the clearance between the fender well and our drive as compared to existing tire clearance on the inside and by adding a wheel spacer adapter, we can gain some additional space outside from existing tire/fender skirt clearance. A one inch wide space may be obtainable to shoe horn in our final drive without the need to modify the existing sheet metal and plastic.

http://www.poulsenhybrid.com/images/...eb2010_004.jpg

This solution (poulsen hybrid, was mentioned here) would easier, and more universal. If you go for chain, it could be even possible to fit in 3/4 inch clearance.But any fitting inside wheel will not work, because hub is positioned in the middle of wheel..

Final Drive Considerations

Most motorcycle final drives use a standard industrial 14m pitch belt and pulley arrangement between the transmission (small diameter) and (large diameter) at the rear wheel. There is quite a vast selection of pulleys available from both OEM and after market sources in aluminum and steel amongst the various motorcycle brands. Selecting the most desireable ratio to begin with and changing later on if needed would be pretty painless. Good cheap used motorcycle parts are readily found just about anywhere.

For instance, on some of its models past and present, Harleys use a 70 tooth aluminum sprocket/pulley about 13" outside diameter with one flange integrally cast into it. It uses a wide belt but it could be easily machined down for our 3/4" wide belt requirement and match up nicely with the 14" Insight wheel.

Fastening the pulley to drive the Insight wheel must be done in a way that will not interfere with normal tire changing. The best way would be to use an adapter that does not alter the existing Insight wheel in any way and would be therefore entirely separate from it. This pulley adapter could also contain the necessary wheel spacer. The pulley/adapter assembly would slip over the 9" brake drum, would be deep enough to extend beyond the tire and would fit over the wheel lugs before mounting the wheel.

I haven't looked under an insight in a few years but is there any way to adapt the rear end from a Civic WagoVan to the insight? the wagovan came with a four wheel drive option so of all the vehicles that have rear wheel drive it seems like that one might fit with less modification, allowing for a larger single motor instead of hub motors.

STASKA: Thank you for your suggestions.

Please note that Poulsen on their web site say that the system "WILL BE AVAILABLE" and quote a tentative price of $8600. Like the abomidable snowman there are a lot of news reports about it but unlike the yetti, there are few if any sightings. The picture you show us looks to me like a good "photoshop" job.

Just like another wheel, the drive adapter I propose is to be mounted on the hub between the brake drum and inside the existing Insight wheel and is to extend over the brake drum and past the tire to carry the drive pulley/sprocket between the fenderwell and inner side of the tire.

RYLAND: Your suggestion to use an existing Civic Honda driven rear end would allow using existing Insight wheels and probably other parts well. I have not studied out the possibility of grafting the Civic driven rear end parts onto the Insight rear end or of sustituting the Civic rear end for the Insight rear end.

In either case, modification of the existing Insight would be considerable and might involve restyling the Insight rear fenders/skirts if the Civic wheel track could not be shrunk. Finding room to accomodate the rear end differential and motor might require a good bit of frame and sheet metal work in addition to finding or building some kind of structure upon which it could be supported.

This would be a very ambitious project and is way beyond what I am ready to take on at this time. Thank you for your suggestion.

The Insight will cruise quite well on 5-10HP depending on conditions, but it would take forever and a day to get up to speed.

http://www.autozine.org/technical_sc...ight_power.jpg

My Insight sees 3000RPM if I want to accelerate at the same pace as the masses, which I do in traffic. This suggests around 35HP. Yesterday, I merged onto the interstate at 3500RPM and full assist, suggesting 50HP, but perhaps you'd fire up the gas engine for such an occasion. These figures are for a 2000lb car + driver. Add batteries, and you'll need to add a little more power.

According to the above torque curve, the Insight makes 12HP around 1100RPM.

I create a sketch of your idea. Is it correct ?

I show poulsen as as possible drive, not as current product. It is possible to mount etek style motor with addition hub for gearing on side beam of poulsen. It will make less unsprung weight also. And on top of it You could make a nice shell. Or in case with insight - go for even narrow tire ant mount it under standart whell cover..

Btw - price for poulsen motors is 3500, 8500 is for full kit with battery.

Hugh, are you good with Photoshop? Or MSPaint? There's not much room back there, but perhaps it's enough.

http://farm6.static.flickr.com/5084/...38b88429_b.jpg

http://farm6.static.flickr.com/5206/...d4804a17_b.jpg

Please excuse the aero disaster. You can see coroplast running from my gas tank to my spare tire well in the first pic, but I really have no coverage to the right of the muffler.

RobertSmalls: Thank you for your "Insightful" analysis. Your experiences driving the Insight pretty much parallel my own although I drive a CVT. However, I am sure that driving an MT car does give you a better feel for what is going on than with the CVT where most of the thinking is done by the machine itself.

Generally, the ICE would be running at all times and the Eteks would be throttled through an additional accelerator pedal located near where a clutch pedal would be. For MT, some kind of multi-function gas pedal could be worked up. Adding the twin Eteks here would serve the same function as adding another IMA motor that could be engaged or not, each through a simple dog clutch. To keep from burning up the CVT start clutch it is good driving practice to make sure that all shift changes are done in the 0-4mph range, so dog clutch shifting there should work out OK. An MT Insight probably could take better advantage of this added assist than a CVT but for low speed driving around town it should prove to be useful enough to be worth the effort.

Staska: Thank you for the colorful sketch. It is correct and a lot clearer than a word description.

You are right about the unsprung weight being a problem with the Poulsen setup. They probably will have to use a heavy duty truck/trailer tire to prevent blowouts. There is another problem also, and that is the one concerning the torque arm connecting the wheel-mounted-motor to the chassis. This arm must be capable of changing length because the car's suspension probably travels a different path than the arm's swing.

An Etek motor weight is about 23# bare, add some kind of torque multiplication/speed reduction (4:1 or more) and you are back up to that 35-40# range. If you move the Etek motor up the arm toward the pivot, you will lessen the unsprung weight and if you have a large pulley mounted to the wheel and small at the Etek motor you could probably get about 23:80 at most which is probably not enough. You might need some additional multiplication/reduction.

RobertSmalls: Your photos are much appreciated. They are a lot better than what I have been working with. Thank you very much.

As far as I know, "photoshop" means that an existing photo has been tampered with in some way to make it appear to be something other than what it was when it was taken. I think the Poulsen motor was skillfully drawn or transferred on to a stock photo of a car.

Honda does not allow for much wasted space in any of their desgns. When Honda added the CVT version of the Insight, they had to find room for the transmission control module and they wound up placing it under an added lump on the passenger side floor. It may be just a Honda engineering tradition of tidiness.

My hope is that it is possible to find space for the pulley/sprocket by moving the tire/wheel out and lessening the clearance space both at the fender well side and at the fender skirt and by adding a wheel spacer. It may become necessary to modify the fender skirt which is plastic and not a critical structural menber.

Also, there appears to be some space between the rear bumper cover and the rear aluminum body panel and it is in this space and below it in which the motor assembly on each side is to be located. Again, not much space but clear of any critical structural members that might interfere.

Your photos show the end of the tubular rear axle beam trailing arm into which an internally threaded plug will be welded for a Heim rod end. One end of a connecting link between the trailing arm and the motor assembly will be achored there. This link will maintain a near constant distance between drive and driven pulleys for a near constant belt tension.

Could you post the whole rear suspension of insight ? I think, there may be one elegant solution

Yes, you are rigth about possible solution with eteks. I also thought oabout positioning etek even on end of trailing arm. It would make unspung weight close to nilll. For mount point - i will try to show it with my fiat, and some skech-up later.

This technology can be used for good OR evil. You could use PhotoShop (or MSPaint, which I believe is the program that Staska sketched in) to annotate an existing photo, or to illustrate something you haven't prototyped yet.

Hugh, surely you plan on shifting to N and shutting down the ICE while using your rear wheel drive. Otherwise, you could simply make like Peter Perkins (and me) and run the IMA motor off of grid-charged batteries. It's not the most efficient, and it will never let you kick the gasoline habit, but it's cheap and easy.

Staska, this illustration came from the Majestic Honda parts catalog. Is this what you need?

http://www.hondaautomotiveparts.com/...3s3y01_b29.png

I have found it by myself:

http://www.insightcentral.net/_image...suspension.jpg

Staska: Yes, the ideal location for the drive pulley centerline would be the centerline of the rear beam pivot. When I initially considered this approach, finding both the available necessary space and suitable available components to make this method work had evaded me and continue to be the insurmountable obstacles both with regards to money and time to get it done. Cutting into the side of the Insight and coming up with something that works and looks correct/good is not easy or cheap.

Most of my work is done with paper and pencil sketches. ACAD is then used to get a mathematically correct layout. I guess it is time to find out what Photoshop and MSPaint are about.

With the CVT, shifting into N and shutting down the ICE and driving from the rear wheels would be ideal and probably could be done at any rear wheel drive speed. As far as the CVT is concerned, it would resemble the car being towed and the same restrictions should be met. However, starting up the ICE (as from a forced stop) and shifting back into D while underway at speeds above 4 mph could probably damage the CVT start up clutch over time and probably should be avoided. With the MT none of these restrictions would apply and you could enjoy a full EV mode if you could live with the limited acceleration you mentioned, however, if you used Mike Dabrowski's MIMA you should be able to get assist from the IMA motor.

Drive Considerations
 

If a target maximun speed for our rear wheel drive is to be 60mph (926rpm for Insight 165/65R14 Bridgestones) for instance and the maximum rpm for the Etek motors is to be 4000rpm, the drive reduction ratio is about: 4000:926=4.3:1 (.23) If we keep with using the 14m motorcycle drive parts for our final drive, this ratio is not obtainable directly with any of the available 14m belt drive components as far as I know, so a two step reduction will be needed. This could consist of two pairs of pulleys or a pair of pulleys and a gear box.

The Etek motor is not enclosed so we will need to enclose it and ventilate it or place it where it is protected from splash and dirt contamination. If we keep the final drive as low as we can with ample road clearance and the motor up high and dry, we come up with something that resembles an electric outboard motor. (Briggs & Stratton did sell such an electric Etek outboard motor. If we could obtain a pair of these, our drive would be almost complete, however, these used a brush type Etek motor and I don't think they developed 6hp and they had no need for a neutral clutch or reverse gear.) For our purposes, it is better for us to find a suitable outboard lower unit and adapt our Etek motor to it. Also, we can take advantage of the forward-neutral-reverse clutch that is built into most lower units. We will need that neutral to lessen the drag of the unit when it is idle.

Sorry when. I dont see whole image. From my point of wiev, i cant see how you will round chain across suspension beam.

Btw - how does drive axle in prius look ? Does it have so colled intermediate shaft ? or it is only one part for one side..

Staska: You can probably find someone on one of the Prius forums or Ecomodder who can answer your questions about the final drive used there.

When sufficient space for a drive could not be found near the rear axle beam pivot for the rear wheel drive, I decided to look elsewhere. In a previous reply (above), I discussed placing the rear wheel drives BEHIND the rear wheels into the space between and below the rearmost sheet metal and the plastic rear bumper cover. A series of good photos of this area of the Insight can be found on Yves Morrissette's Insight Mods blog Welcome to my Honda Insight home page .

With careful planning it may be possible to install the drives in this space with a minimum modification of metal and/or plastic Insight parts.