Hybrid conversion Toyota pickup. (Compressed air assist/regen) - Fuel Economy, Hypermiling, EcoModding News and Forum

grinderdust · 06-21-2012, 09:57 PM

Hello everyone, I am very interested in making a hybrid package to bolt on my Toyota pickup for fun and savings. I am taking the bed off soon to restore it and add tiedown points, a hitch and a steel plate for a crane. Perfect time to do some additional mods!

It seems to me that compressed air is the way to go because the parts are cheap and available. Also charge/discharge rate is not as much of an issue as an electric so power can be developed and spent quickly when needed.

I would like to mount a twin cylinder cast iron compressor I have laying around in the front of the bed next to a clutch/gear reducer which would then have a slot for a belt to go to the driveshaft. I would then put two airtanks under the the body on either side. Then an air motor mounted on the other end of my clutch assy. Simple eh? Prob. not.

On to the many questions I have

Why isn't every one doing this? It seems like it will only cost a few hundred at most. It will be a little noisy but so are trucks and soundproofing is possible. How fast does a drive shaft spin at say 70mph? Definitely need to gear down a bit. Just how much to be safe is the question.

Is an air conditioner clutch good or is there something better? Does it have sufficient holding tourque? I know they safely spin almost as fast as a crankshaft.

What about a suitable motor? does anyone have an idea where to obtain a suitable air driven motor on the cheap? What specs and design would be best for the motor if I must pay market price?

Last but not least, what are your safety concerns? I can obviously forsee the necessity for rock shielding for the air tanks, pop off valves for over pressure and proper belt guards. Maybe a noise and shrapnel shroud for the compressor itself. All in all though it seems safer than all those batteries and high voltage, not to mention the environmental and actual cost. Please convince me I'm crazy or I'll do it I swear.

ecomodded · 06-23-2012, 01:20 PM

your Shaft RPM will change as your motors rpm changes, the transmission will alter the RPM as you change gears. in top gear it should be 1:1 if memory serves me correctly.
If you had or bought a pto( power take off ) on your transmission you could add power through it, to run the drive shaft off a belt would require cogs, imo, the belt would slip without them. "Maybe" once up to speed the belt could take over, i have concerns of the belt torque on the u joints as well.
Perhaps drive the air compressor off the drive shaft and power the vehicle off the PTO.

In short without a PTO it sounds problematic.
Have you seen/read about any working examples of your idea?

grinderdust · 06-24-2012, 08:01 PM

Thanks ecomodded. I am aware that the drive shaft changes speed as the truck speeds up. I am trying to get an idea of the max rpms at highway speed so I can gear down to a safe rpm for the compressor. My plan for the belt is to machine the center out of ribbed pulley, slip it over the shaft and weld, epoxy or clamp it in place. I could use a camshaft pulley off of a honda or similar with the toothed belt if slippage becomes a problem. I think some slippage adds a safety factor if something should fail. I could mount the pulley right on the hub of the transfer case or rear diff if anyone thinks the driveshaft would be affected by the belt tension. I have not seen any working vehicles designed in this way but I really don't see how it could not work. I think that a hybrid using such a simple design would actually be a hard sell in the consumer market. Much like a home remedy, If there is no profit to be made there is little interest among corporations. It just seems like one of those hillbilly things that works great but noone wants on their vehicle. Hypermiling in general seems to fall into that category. Everyone knows you can save fuel but automakers keep making the cars harder to use that way. It's hard to even find a manual trans. these days. 99% of the population just wants to get there in absolute comfort and make a fashion statement.

ecomodded · 06-24-2012, 08:37 PM

Its a good idea.

If it works it works,hillbilly or not. A lot of the greatest engineering problems are solved by the most simplistic method imaginable. So simple is good.
Especially good for those with little to no funds. Might be able to make it from 95% recycled parts. Which makes it even greater of a discovery.
If you think you could weld a pulley to the drive shaft,keep the welds in balance, also check with a welder. Off hand it must throw the balance off by a large amount, unless some how the torque keeps it in balance.. i do not know!
I think your idea of going off the transmission output sounds really good, could even weld it off the front u-joint's backside, nearest the tranny.
Regenerative engine/transmission braking. You are onto something.

Most cars travel at about 2500 to 3000 at 70 mph.
In top gear if your motor's RPM are 3500 then your driveshaft would be about 3500, if your high gear is 1to 1, which i think it is,but you should check.

Ryland · 06-25-2012, 01:00 AM

I wouldn't bother with an air motor to try to power the truck with compressed air, instead I think using the compressed air in the gasoline engine with a venturi to increase the volume, so your compressed air tank is helping the gas engine in the same way a turbo charger would help reduce pumping loss.

grinderdust · 06-25-2012, 03:31 PM

Thanks Ryland. I have considered using air to help the engine run. Although this may help the engine run and eliminate pumping losses, it requires tampering with the engine and some very technical refinement which I have neither the time or facilities to accomplish. I don't think I can improve the Toyota 22re (worlds best all around gasoline engine?) in my yard. I don't even have a garage. The idea, for me at least, is to limit the use of the engine as much as feasible. In my design, the regen comes before the engine losses and is able to return energy directly to the drivetrain, again before the engine losses eat up most of what is gained. I'm not trying to be smart because I think Rylands Idea has some real merit, especially for some types of engines which I am keeping secret for now.
Here is a link to a very efficient design for an air powered motor that I would love to play around with. Engineair’s Ultra-Efficient Rotary Compressed-Air Motor It seems I am the farthest person on earth from that motor both physically and financially. Does anyone have any Idea where I can get an air motor that would move a light truck on the cheap? I'm guessing 10 or 20hp would be ideal for most situations. I really don't care about super efficiency right now. Just need it average and cheap for proof of concept. I have everything else including a rough Toyota laying here. I would even settle for a design to turn the compressor itself into a motor but I think this would be a compromise. My internet time is limited. Any links or information of relevance would be greatly appreciated.

smokey442 · 06-25-2012, 05:20 PM

Here's my thought. Make cylinder 1+4 into the air expander. Run cylinders 2+3 run in the conventional manner. Use exhaust valve as the air inlet and use 10-15% cutoff. Intake valve now becomes air exhaust. This requires custom ground camshaft with two lobes per position. Use an a/c compressor to replenish your air supply.