Retrofit kit said to transform cars into hybrids

[Right Lane Cruiser]

The next step will be to retrofit the kit on 30 state-owned vehicles for testing.

R. Colin Johnson - EETIMES - July 1, 2009

I wonder how they handle with the unsprung weight? --Ed.

PORTLAND, Ore. — A former IBM electrical engineer has designed a retrofit kit that he claims can transform existing automobiles into hybrids by placing an electric motor inside each wheel, thereby doubling gas mileage.

Charles Perry, a former IBM product development researcher, recently received first prize for his invention at a green energy competition at the Tennessee Technology Development Corp. The patent pending Plug-in Hybrid Retrofit Kit will be developed into a commercial product by Palmer Labs LLC (Reston, Va.).

"What makes our approach different is we don't need to modify anything in existing vehicles to turn them into a hybrid," said Perry. "We install the motor in the space between the brake mechanism and the hub without any other modifications."

According to Perry, 80 percent of U.S. drivers make daily trips of less than 30 miles at 40 miles per hour or slower, all of which could be powered by his 10-15 horsepower electric motors to save as much as 120 million gallons of fuel per day in the U.S. alone, he... [Read More]

[Damionk]

Where would the batteries go? Would this be used in combination of the ICE? How would it be controlled?

The price doesn't seem too bad though ($3000-$5000).

[beatr911]

It will be interesting to see the payback period, how seamless it is to use and how many vehicles will be supported. 3-5K is pretty darn cheap. That must not include installation or batteries.

Yeah, unsprung weight will be a factor. Fortunately the mass increase is near the center of the rotating mass so it is in the best location possible for a weight increase at the wheel.

[Taliesin]

Something to consider...

However:

Originally Posted by beatr911

Yeah, unsprung weight will be a factor. Fortunately the mass increase is near the center of the rotating mass so it is in the best location possible for a weight increase at the wheel.

Another consideration is the added weight in the trunk (or in my case the bed of the truck).

That might take away some very useful space.

[Mr. Pancake]

"What makes our approach different is we don't need to modify anything in existing vehicles to turn them into a hybrid"
I don't see how this is true. Besides adding a battery pack and routing wire to the pack, you're also going to need something to control the motors and some way to communicate between the motors, ICE, gauges, etc. And do you run the ICE with the motors, because where do you get braking and power steering and all that other fun stuff you kind of need? I'm all for inventive ideas to save gas/cut pollution but I don't see how this would only cost $5,000 for all that it would take to turn an ordinary car into a hybrid. Taking out the ICE and converting to an electric car seems more feasible.

[JusBringIt]

batteries go into the trunk...From what I read, the electric motors are standalone.

[Trick]

Fascinating...I might be interested in purchasing one of these, if it turns out to work and if I don't have to take apart my entire car and reassemble it to make it work.

[R.I.D.E.]

Sounds like a form of launch assist to me.

regards
gary

[WriConsult]

I've had the same idea for "hybridizing" an existing FWD car for several years. Some obstacles to overcome, none of which are insurmountable.

• As already mentioned, the extra unsprung weight is going to substantially alter the behavior of the suspension. At a minimum some re-tuning of the shocks and spring rates would likely be needed.
• Although most EVs don't have multiple gears, most of them do use some sort of gear-reduction mechanism to allow for more optimal performance and efficiency at the low speeds for which the benefits of this system are touted. I'd be interested to know if the proposed solution includes some sort of integral planetary-gear system to provide gear reduction, or maybe the developer has come up with a motor that works more optimally at lower RPMs.
• Also as already mentioned, you'll have to make some decisions about placement of the battery, motor controller and charge controller components. Assuming you're using NiMH and are willing to give up some space it shouldn't be a huge problem. A 3kWh pack might weigh 120-140 pounds and take up a space approximately 13"x10"x10" in a cube-ish shape, or 13"x28"x4" in a flat pack. Doable.
• You'll have to make the decision about how to control it. If you have a drive-by-wire system such as on my VWs, you could put a mode switch (ICE / BEV / hybrid) on the dashboard and drive the electric motors off the gas pedal (and, for safety, the clutch switch) when either EV or hybrid mode is engaged. the Otherwise you'd need some kind of separate potentiometer-based control, ideally mounted on the shifter. You'd probably also want some kind of separate interlock or deadman switch to make sure it doesn't get engaged accidentally. The latter approach is simpler to build and allows easier tuning of the ICE vs motor power balance, but ends up being a lot of controls for your average driver to manage (although I'm sure most of us could handle it, even on an MT).
• Assuming this is an A.C. motor you'll have to decide how to control regen. Today's hybrids do it automatically based on brake vacuum, battery SoC and very complex algorithms, and even then some people still don't always like the resulting brake feel. I'd prefer keeping the system simple and having a separate control for the regen (of course that does mean one more control to manage while driving ... but also gives us control freaks a lot more variables to manage in our never ending quest for higher mpg numbers).
• This amounts to a mild AWD system (when used along with the ICE), which is beneficial and just fine when you're accelerating. But you'll need to take care about engaging regen on slippery surfaces since it's engaged at the rear wheels. If regen is engaged during braking, you could end up applying too much braking force to the rear wheels (I've learned firsthand, from one of GM's notorious X-cars, how dangerous this can be). If regen is engaged while driving along under ICE power, it's effectively accomplished by transmitting engine power through the front wheels and the road itself back to the rear wheels. That's just fine on clear roads but either regen scenario could be dangerous in icy conditions, so if it isn't controlled manually there needs to be a way to disable it.
• Also as already mentioned, if this is meant to be capable of full EV mode and not just a hybrid assist system, the car needs to be capable of steering and braking effectively without the ICE running. The safest thing would be to remove the power steering pump and convert to manual steering, mostly feasible only on smaller cars. And you would want to add an electric vacuum pump to keep the brakes working, and upgrade the 12V battery to the biggest Optima yellow top available to handle all the cycling that's going to be going on.

I would agree you're probably not going to pull something like this off for $5k. My guess is that's just for the motors and maybe the controllers. The batteries alone (for the 3kWh-ish pack I would envision) are going to run $3-4k at a minimum on top of that. Mr. Pancake, you're absolutely right that it could be simpler to just convert to a full BEV, which would require a larger battery pack but lose a lot of weight and complexity while eliminating the challenges of designing the driver controls. But (1) you'd need a 3x larger battery pack, which is simply not commercially available, period, and (2) you'd have a BEV with limited range. The advantage of this option is it really is a DIY hybrid with unlimited range, for a fraction of the cost of the Lithium-based BEVs on the horizon.