Mild electric hybrid using a Permanent magnet PMG 132 motor?

[Ryland]

Thing is, a lot of the throttles are just a 0-5k ohm pot with a micro switch to turn it off 100% when it's at -0- so adding another resister in there to vary the input is pretty easy, same with having another throttle in parallel, so say you tend to drive only a few miles to work every day, you can crank up the boost and once up to speed take your foot off the gas, keep the car in gear and use the thumb throttle to maintain speed for a few miles, not as efficient of course as it would be if the engine was not turning at all, but much simpler.

[blownb310]

I like the mild series hybrid idea being discussed in this thread. Especially the simplicity of bolting on a motor where the A/C compressor would be. Regarding a sprag setup for the assist motor, I'm wondering if an a/c compressor clutch could be used?

I have a particularly long hill that I have to climb going to work every day. I'd love to be able to add about a 5 h.p. assist while climbing it. I know nothing about electric motor technology, but I wonder if a starter motor could be used somehow? [I'm trying to think of a cheap source of a powerful low voltage DC motor.]

Mike

[Ryland]

Originally Posted by blownb310

I'm wondering if an a/c compressor clutch could be used?

there would be very little reason not to have the electric motor spin with the gas engine, an electric clutch like an A/C clutch would add more weight, drag and add to the electrical power needed.

I have a particularly long hill that I have to climb going to work every day. I'd love to be able to add about a 5 h.p. assist while climbing it. I know nothing about electric motor technology, but I wonder if a starter motor could be used somehow? [I'm trying to think of a cheap source of a powerful low voltage DC motor.]

A starter motor tends to over heat if you use it for more then 10-15 seconds at a time, that is why your owners manual often tells you to let it rest for 10 minutes for every 10-15 seconds of cranking over, if your car does not start, they are working at their max output just to turn the engine over.
Part of my idea of using a Golf Cart motor is that you can buy them used for about the cost of a rebuilt starter motor, or about $150, only they are a much larger motor that is designed for a more sustained use, they do have the draw back of not having a support bearing on the drive end, but I see that as an advantage, make that bearing support part of the bracket that holds it to the vehicles engine block.

[Daox]

If your electric motor is putting out any reasonable amount of power, there is no way an A/C clutch is going to be able to hold that much torque.

Have you looked into how much the overrunning clutch is going to cost Ryland?

[Ryland]

Originally Posted by Daox

If your electric motor is putting out any reasonable amount of power, there is no way an A/C clutch is going to be able to hold that much torque.

Have you looked into how much the overrunning clutch is going to cost Ryland?

Looks like I can get the bearing clutch that is used in a heavy duty over running clutch for $111 or so from Mcmaster Carr, it can handle 59 foot pounds of torque, Specs for the NetGain Warp 7 motor seems to say that it's peek torque is around 45 foot pounds and that is a slightly larger motor then a standard golf cart motor.
But I don't think a clutch would be needed at all, at least not with my idea of having the motor throttle match the gas engine throttle so the motor is always giving a little boost, the only time I could see you not wanting the motor to run would be a cross country trip where you didn't have a chance to charge, but even with an 8 hour trip a 100 amp hour, 48v battery pack would be able to sustain a 600 watt draw, so after losses maybe half a HP of added power, if it really takes 15hp to maintain highway speed then that would be a 3% gain in your worst case of driving 8 hours straight, of course when was the last time you drove 8 hours straight? that's why we have trains and airplanes! and your biggest gains would be while driving short trips where you could use the whole 4,800 watt hours (just an educated guess at pack size) over the course of a 5-10 mile trip to off set gasoline use.

[jdchmiel]

If the electric motor has very good bearings, wouldn't spinning it at a continious RPM really not eat up very much efficiency? Like on a purely cost basis, if the only significant benefit to adding an overrun clutch is to save brush life, how long do the brushes last, and how much do they cost, and how difficult is it to service the motor? How does that level of time, effort, and money compare to custom building an overrun pulley system?

Contrasting opinion side note, Ford Crown vic police alternators are 200 amp units that I think are 5 or 6 groove wide pulleys with a built in overrun. I bought two of them off ebay for around $100 total to use to build a tig welder. I do not know what kind of power they would handle continiously, but they must be rated for intermittant ~3.7 hp based on 14v @ 200 amps output..

And another fun thought - a timing belt transmits a lot more power on a continious basis.. If you can get rid of all of your other accessory belts, you can add a second crank timing pulley in place of the main crank pulley for a drive belt, and adapt another geared pulley to your motor. You can get that pulley from a timing belt + idler kit from many motors. for instance, my subaru flat 4 had 3 if I recall that were about the same diameter as the crank pulley for a close to 1:1 drive, and the cam gears obviosly are always a 1:2 ratio on all engines. Garages just throw many of these out all the time for each timing belt job they do!

[Ryland]

My mistake, I was looking at the wrong chart, the warp7 puts out 65 foot pounds, but again, it's a larger motor and I don't think that a clutch is needed, a set of brushes costs $50 for low quality ones from any golf cart shop and $45 for high quality ones from Helwig Carbon and they should last a long time because they will be under very little stress, after all they would only be helping the engine along, not moving the whole car.

[Daox]

That is kind of what I was thinking too. If Mort's 5% rating is true I don't think you'll be burning through brushes that fast at all.

Oddly enough I know a guy from our local EV club who works at Helwig in their test lab. He got me some new higher efficiency brushes for my mower's motor. Great guy to talk to about motors.

[ncwa]

Hi Everyone - I am glad to see other people interested in this approach! I converted my 1966 Mustang into a plug-in-hybrid a little over a year ago. It was a really fun, yet challenging project. There were a few times during the build where I had to pause and really think about where the gas and electricity were running around the car (yikes!). I also had my share of burned out or incorrect parts, but all in all I am very pleased with the results.

I considered mounting the motor in the location of the “optional” ac compressor but ended out locating the 30Kw peak brushless PM motor under the headers replacing the alternator. I had to build custom mounts and triangulate them to the engine block. I am currently using an oversized v belt. I am “waiting” for it to break but so far it is holding up like a champ! I can start the gas engine with this set up (triggered by throttle advance) but the belt slips, so I don’t often use this method. I haven’t found the right pulleys for this motor (straight 200) to allow me to switch to a synchronized belt. Once I do, I will be able to properly start/stop the ICE!

The car is zippy and makes really unique sounds! The dash is loaded with gauges (I guess that makes me an engineer!). It is great to watch the amps rise up with intake vacuum rise, indicating less fuel flow. It is also rather entertaining to modify my dual throttle advance curves (slope and start points) to discover unique performance characteristics.

A smaller engine running closer to peak efficiency would likely yield better results, as would a proper ICE! I started with around 12-15 mpg’s on this old worn motor. A local shop helped me tune it to the high teens. Aero mods (under the car) were by far the best value mods bringing my mpg’s up to the mid 20’s! Then with the hybrid system, I am now seeing 30-35 mpg’s without hypermilling! I know, I know, these are low numbers for you pros, but this is big step for me Someday I might rebuild the ICE and switch to 5-speed, allegedly bring my mpg’s up to 30 – then with the aero mods and 30 Kw electric motor, I might do even better! Hey I can dream right! I might even have to start hypermilling if I can find the right pulleys…

Good luck to you on your explorations!

[steffen707]

Originally Posted by Ryland

I've gotten 65mpg while driving 70mph just because I had a tail wind, wouldn't this be like having a constant tail wind?
Changing the whole rear suspension and adding another drive train is not something I'm interested in doing, bolting a motor to existing threaded holes and using an existing V-belt pulley is a modification I'm willing to do to my otherwise stock car that is in great shape.
I'm thinking that the big hold up on this is going to be a battery pack, because I don't want to fill my trunk with golf cart batteries I'll most likely hold off on this project until I buy the lithium battery pack for my electric motorcycle, I'll have to double check but I think that might fit where the A/C condenser would live, or at least a portion of the battery pack could, the spare tire well would be another option.
Mort, do you have any charts on how much power V-belts can handle? I would imagine it's dependent on pulley size, larger being better up to the point where the belt over speeds.

I WANT ONE! I've seen a civic with a huge supercharger bolted to front of the engine where the A/C goes. This is an awesome idea you came up with. I look forward to reading the rest of the thread, and hope your plans come to fruition. My civic with vx engine is awesome in lean burn, but quickly falls out of it on on slight hills. I imagine a 10hp external boost would keep it in lean burn far longer.