# Converting to a hybrid ?



## alpa (Nov 12, 2009)

Hi,
This is my first post here. Not sure I'm posting in the right section or even on the right forum  .
I wonder if somebody here is converting a petrol car into a hybrid one. I'm especially interested in this topic to convert old cars like my classic manual Mini.
My idea is to replace the alternator with a few KW DC (brushless) motor. It would help the engine to make accelerate the car and during low speed cruise phases (in town). During this periods the IC would run in the stratified mode just to maintain itself in rotation to avoid wasting electric power on the compression work (no variable valve lift in old engines). The motor would also act as an alternator. An electric throttle (like) device is of course mandatory.
Any input would help.
Thanks


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## madderscience (Jun 28, 2008)

Hello-

These forums are largely focused on pure EV conversions, but we do have a few other people considering hybrid conversion concepts.

The easiest thing to do if you want a homebuilt hybrid seems to be to find an all-wheel drive car and disconnect the rear axle from the rest of the drivetrain and hook an electric motor straight to it, then add the rest of the EV components (batteries, controller, etc) to power it. In the case of a mini this would mean installing such an axle from another vehicle. The big disadvantage of this system would be even more weight than an EV conversion, since you did not save any weight by removing the engine, fuel tank, etc.

Another alternative would be to try and fit the drivetrain from a wrecked hybrid vehicle into the mini, but I know there is not much room in there; not sure what sort of micro-compact hybrids might be available in europe.

As for your idea, I'm not sure you could get enough power through the fan belt of the car to significantly assist the engine. And you'd still need an alternator or something else to run the 12V system in the car anyway.

Depending on your needs though, the mini would make a neat little (pure) EV. 

What about a smart car diesel engine and transaxle? I bet that would work, though it isn't EV at all.

Good Luck.


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## mxmtech (Apr 21, 2009)

I've been doing a little thinking about this as well.
My idea is to use a front wheel drive vehicle like the Geo Metro and convert it to electric putting the batteries in the back.
Then take a Volkswagon transaxle and build a compatible frame that would interchange with the Geo battery pack.
City driving - slide in the rear wheel pack with the batteries.
Going on a trip - slide in the rear wheel pack with the ICE complete with gas tank.
Not really a hybrid, more like an instant conversion pack.


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## alpa (Nov 12, 2009)

Converting to a pure EV is not an option. I live in a stupid country France where conversions are totally forbidden because there is no way to register a petrol car as an electric one. The IC engine must be physically present and I have to produce CO at least during smog.
Also the same question will arise for many other classic cars, people don't want to deeply modify them while they like the EV smooth and clean driving.

A Mini is a light car (650kg) so driving it through a multi-v belt like the one used for A/C or superchargers is perfectly enough, 5HP are enough to cruise in town and start the car on traffic light.
A DC motor will serve as alternator when not being used to drive the car.

My first plan was to install a second (electric) engine at the rear. Mini has a special setup with the gearbox under the engine, so putting the entire front engine frame with the gearbox solves lots of problems. Then bolt a motor in place of the IC engine. I even bought a rusted Mini to make a prototype of the installation. However I realize now it's quite complicated because there are so few room in the car, and now there are very compact DC motors I can just bolt in place of the alternator.

The basic idea of the management is simple: while the demanded load is low the DC motor drives the car and the IC engine is just barely idling, there is no need for a good quality idle as the DC motor will smooth the RPM. During this phase the IC engine is never in the transient mode, which is the most petrol consuming.
When the car is stopped and batteries (say 2 x 100Ah deep discharge lead-acid) are charged the engine goes down to 500 RPM idle (it works perfectly on my engine), the alternator stops working and the car peripherals stay on batteries.
On a high load demand the DC either helps the IC or it's switched to an alternator mode.
A start/stop IC engine system is also to be studied. However the warm "clean" IC start-up is still a mystery to me, I'm not sure old engines especially like the Mini's one are able to do that. I'm more thinking of dynamic cylinder switching off.


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## dataman19 (Oct 7, 2009)

Alpa,
Have you considered a planetary gear box?
This is the Prius gearbox.
The planetary gear assembly would allow for two separate power plants.
..
When both power plants are producing power - then the power produced would be the sum of the two.
..
When only one power plant is producing power - then the power applied would be roughly equal to the power capacity of the power plant producing power to the drive wheels...
Now, in reality, you have a slight decrease in efficiency (about 2% to 5%) with a planetary gear set. But the overall gain is a whole lot better than not when using two sepratae power plants.
..
Want to know more about gear sets? Here is an excellent tutorial (even has animations to illustrate the points):
http://www.carbibles.com/transmission_bible.html
..
Pay particular attention to the planetary gears sets used in auto transmisstions. ::
...
If you Drive the outer ring with the electric motor, and the planetary gears with the gasoline motor - you essentially have a Prius Hybrid drive train.
..
Dave Mason
dataman19


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## alpa (Nov 12, 2009)

Dave,
The only feasible mod I could imagine would be to modify an auto transmission, luckily it existed on Mini.
However I don't see how/where would I connect the second motor in the chain of planetary gears. There is one input, one output in the gearbox.


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## dataman19 (Oct 7, 2009)

You would have to have a gear re-machined in a machine shop to add an output shaft (or find a Prius in a salvage yard).


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## gor (Nov 25, 2009)

alpa said:


> Hi,
> This is my first post here. Not sure I'm posting in the right section or even on the right forum .
> I wonder if somebody here is converting a petrol car into a hybrid one. I'm especially interested in this topic to convert old cars like my classic manual Mini.
> My idea is to replace the alternator with a few KW DC (brushless) motor. It would help the engine to make accelerate the car and during low speed cruise phases (in town). During this periods the IC would run in the stratified mode just to maintain itself in rotation to avoid wasting electric power on the compression work (no variable valve lift in old engines). The motor would also act as an alternator. An electric throttle (like) device is of course mandatory.
> ...


well, to have a parallel electric plug-inn system, tapped to engine, shaft or wheels - helps engine to run easier,cooler, on lower rpm -good idea, how to achieve it with easy mod - good question; 
look for hybrid types and "electric supercharger" on the web, Saturn hybrids - i believe?
p.s. it is easy to tap to alternator or to serpentine belt, though less complications for existing car electronics would be to tap right after the clutch before gear mash or use wheelhubmotors (rear for FWD)
p.p.s. somebody been messing with the starter outlet on flywheel -but i belive they desided it's beter to leve starter alone...


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## alpa (Nov 12, 2009)

gor,
I made a search for Saturn technology description. Looks like it's a wonderful thing (according to US sites) but nobody is able to tell more than it's a hybrid with an electric motor/alternator. 
Would you have a pointer to a better description of this thing ?


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## gor (Nov 25, 2009)

alpa said:


> gor,
> I made a search for Saturn technology description. Looks like it's a wonderful thing (according to US sites) but nobody is able to tell more than it's a hybrid with an electric motor/alternator.
> Would you have a pointer to a better description of this thing ?


yea, i'll check it - it been somewhere... - i'm interested too -at least it would enhance performance without much damage to staff(car,etc) you (i) already have : ))))))
i'm interested too - in outroad application it seems like hybrid drive - could be a good option


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## alpa (Nov 12, 2009)

gor said:


> yea, i'll check it - it been somewhere... - i'm interested too -at least it would enhance performance without much damage to staff(car,etc) you (i) already have : ))))))
> i'm interested too - in outroad application it seems like hybrid drive - could be a good option


My car has a little additional problem: it's so small that I don't have many options  . Right now just having installed injection stuff I don't have windshield water bottle any more, nowhere to put it.
On the other hand it's so light that even a small motor will do a good job.


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## jondoh (Sep 8, 2008)

Hi Alpa,

If you want to drive electric and keep the hybrid option, if you can get a Prius and add this kit, it would be ideal:

http://www.pluginsolutions.com/


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## alpa (Nov 12, 2009)

jondoh said:


> Hi Alpa,
> 
> If you want to drive electric and keep the hybrid option, if you can get a Prius and add this kit, it would be ideal:
> 
> http://www.pluginsolutions.com/


Hi,
I want to drive a Mini. Modern cars are certainly nice but I have a kind of allergy to them, I guess something wrong with me  .
The second reason is that I like challenges. The Mini engine is a 60 years old design, I'd like it to be efficient today.


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## gor (Nov 25, 2009)

alpa said:


> My car has a little additional problem: it's so small that I don't have many options  . Right now just having installed injection stuff I don't have windshield water bottle any more, nowhere to put it.
> On the other hand it's so light that even a small motor will do a good job.


look from other perspective - it so light : ) - it gives you so many options - you can use available e-scooter parts - up to putting their wheels or your wheels on their wheelhubs : ))))


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## alpa (Nov 12, 2009)

gor said:


> look from other perspective - it so light : ) - it gives you so many options - you can use available e-scooter parts - up to putting their wheels or your wheels on their wheelhubs : ))))


That's smart ! I would love to have motors in rear wheels, ideal solution. I'll have a look at them. Thanks


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## gor (Nov 25, 2009)

alpa said:


> That's smart ! I would love to have motors in rear wheels, ideal solution. I'll have a look at them. Thanks


congrats with injection, sorry now you have to make your waterbottle : ((((((((((

with scooters seems funny but hey :

60 MPH (2 aboard - GPS Verified)​ 
85 Miles on a Single Charge​ 
Max Rider Weight:
400 LBS (2 can ride comfortably)​ 
Weight: 353 lbs​http://www.rechargeablelithiumpower.com/oscommerce2/catalog/xm5000li-p-44.html

and it has one rear wheel; car has two... +2 on the front - your major drive wheels
plus - it has to only help your ICE to not work that hard - if it can go on 1000-1500 humminng rpm instead of 500 more under many driving conditions - there is a fuel economy, power boost anything - better than do notng​ 
http://www.rechargeablelithiumpower.com/oscommerce2/catalog/xm5000li-p-44.html


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## alpa (Nov 12, 2009)

gor said:


> congrats with injection, sorry now you have to make your waterbottle : ((((((((((


Sure but I don't need to stop driving, just open the window and pour ha-ha.


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## gor (Nov 25, 2009)

alpa said:


> Sure but I don't need to stop driving, just open the window and pour ha-ha.


lol _ right! dem extra weigh! : ))))
my pump broken - and you know - when it's rain - it pouring by itself!
... who extra picky - can stop in gas station and clean it once in a while
who need extra weight and extra parts?! - more things to break : ))))
LOL


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## IamIan (Mar 29, 2009)

One border line idea is alterations to the Starter and Alternator you already have.

http://www.los-gatos.ca.us/davidbu/hybrid.html

By changing the starter so it can provide you with electric assist continuously ... you are reducing the amount of gasoline your ICE has to burn to provide the kW of power you want ... kind of like a variation on an electric turbo... but instead of forcing air you just apply the force directly to the drive shaft... the amount of electric assist in this method would be limited by the connections of the starter to the drive shaft , the mixed mode starter motor used, and the batteries used.

Then you modify the alternator ... by disconnecting it so it is pulling no load you reduce / remove that power drain from the ICE ... have a relay reconnect the alternator when the 12V battery gets bellow a certain point or anytime you apply the brakes... upgrading to a larger alternator provides more braking power... this is a poor mans type of crude regenerative braking... that is limited to the amount of regenerative braking power it can do by the connections, the alternator , and the batteries used.

If you allow your battery pack to be grid charged you have a PHEV.

When you start out with a fully charged battery and are operating in charge depletion mode you will see the largest MPG benefits... after that point when you are in charge sustaining mode you are functioning more like a conventional HEV ... and your MPG benefits will not be as high as they were in the beginning.

In charge sustaining mode you have two main competing forces and a third minor force ... the additional weight of batteries that lowers your MPG ... the recycled regenerative braking energy that improves your MPG ... using short bursts of the electric assist to help keep the ICE closer longer to its more efficient range of RPM & Load ... the specific route and driving style will determine if the charge sustaining mode is a net MPG benefit or not.

but of course there are many other options far more elegant with many other benefits that this method would not offer.

best of luck


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## alpa (Nov 12, 2009)

That are basically my ideas (I've got few more). Except that I don't see how to replace the starter with a driving motor, there are too many mech losses there.


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## IamIan (Mar 29, 2009)

alpa said:


> That are basically my ideas (I've got few more). Except that I don't see how to replace the starter with a driving motor, there are too many mech losses there.


Upgrading the starter is not the path for a drive motor ... it is a path for a ICE assist motor... This is not a method of pure EV mode operation for zero gas driving ... it is a method of reduced gas usage during driving.

To function as a drive motor you need much much more kW of power ... which means a larger , heavier , more expensive .... everything ... Motor, Controller , Batteries , etc...

If you are staying in the EV range the ICE is dead weight.

If your range includes ICE usage... then it isn't about the zero gas miles ... it is about the total average MPG on a monthly / yearly basis.

If your electric motor is powerful enough to act as the drive motor ... you have a EV... the only reason to retain the gasoline engine is as a range extending feature.... but the size and weight of gasoline or diesel engines does not becomes a performance / range advantage until you get further than ~100 miles per charge ranges.

One method of removing the mechanical losses is the same way Honda did it with the IMA ... put a motor mechanically between the ICE and the transmission ... I still think they should have included a clutch between the ICE and the IMA motors ... the other benefit of the IMA approach is that a single IMA motor requires less space, weight, and cost than two separate motors for Assist ( Starter ) , and Regen ( Alternator ).


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## daxwert (Oct 11, 2009)

Just got me thinking. 
Please stop me if necessary. 

Why not connect the turbinesection of a turbocharger to a small dc motor which will act as a alternator. Now replace alternator(or startermotor) with powerfull DC motor. Infact, remove both starter and alternator because the motor could perform both those functions. Feed power straight from Generator to drivemotor. No batteries for now.

Theory: Exhaust gas turning the turbine generates 'free power' feeding it to a drivemotor which assist the ICE enough to feel the extra power and make it think its going downhill all the time with a strong backwind thus using less fuel. 
Some storage could be a
dded to catch exess generated power which would be available when pulling away.

WHat is wrong with this train of thought?


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## alpa (Nov 12, 2009)

Well connecting to a turbine is a very complicated operation, because of shaft balancing and rotation speed. In this case it's better going directly to a cranksless engine.
Also on SI engine the turbo does not "work" neither even rotate in small charges and idle.

IamIan: I can not convert to a pure electric power for already mentioned reasons. The goal is to improve MPG.
The first step is going to be an idle running at 500RPM as long as battery is charged enough, it's very quite and the consumption goes down (without more CO and HC pollution, I checked).
Then I'll probably try a start-stop system. And then the alternator replaced with an electric motor (needs some pulley mods but perfectly feasible). This last point will also require mods of the engine ECU.


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## daxwert (Oct 11, 2009)

alpa said:


> Well connecting to a turbine is a very complicated operation, because of shaft balancing and rotation speed. In this case it's better going directly to a cranksless engine.
> Also on SI engine the turbo does not "work" neither even rotate in small charges and idle.


I wont need it to work on idle. I would aobviously do some serious conversion on the gearing. What do you mean with 'crankless engine'? Is the principle too far fetched and how many amps could I possibly produce?


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## alpa (Nov 12, 2009)

crankless engine: try google, it's a kind of engines. Usually huge ones.
I can not answer your questions, I have no idea. What I'm sure of is that it's technically quite complex.
Also the energy catched by the turbine is used to compress air, so it's not lost as you seem to think. If you connect another charge to the turbine you'll need more energy to make all that work.


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## daxwert (Oct 11, 2009)

alpa said:


> Also the energy catched by the turbine is used to compress air, so it's not lost as you seem to think. If you connect another charge to the turbine you'll need more energy to make all that work.


Would remove the compressor side of it.


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## gor (Nov 25, 2009)

i saw somewhere - guy did this plane-simple conversion - i believe he just welded sprocket to the semiaxle (something like on pict) - quick and cheap way - but works and doesn't hurt anything 
can't tel now where i saw it, details, was it just temporary 4 testing components sake or not - but idea and setup - superb simplicity and ease to accomplish wise


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## 72opel (Mar 26, 2009)

CAN THIS KIND OF conversion work with an ev? If 10 hp will cruise on level ground in average ev---could 10hp single cyl ice with electric clutch to engage and drive pulley on tail shaft of drive motor work to assist uphills and reduce current draw?


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## TigerNut (Dec 18, 2009)

daxwert said:


> Would remove the compressor side of it.


By way of example, a mechanical supercharger on a Top Fuel type of car typically requires about 10% of the ICE's power output to drive it. In other words, when a supercharged drag motor is putting out 5000 HP, the supercharger requires about 500 HP to compress the intake mixture.

This figure gives you an idea of how much mechanical power might be available at the turboshaft, because the compressor on a turbocharger does the same basic function as a mechanical supercharger. If you assume that the turbo is more efficient (in some cases it might be), then you have to allow for the fact that there is actually less power available from the turboshaft.

While the turbine extracts some energy from the exhaust that would otherwise be wasted, it also increases the upstream pressure in the exhaust, which will reduce your exhaust scavenging and cost you some ICE efficiency. To optimize the production of exhaust gas for driving a turbine when the intake charge was atmospheric, you'd have to do some detailed analysis and tuning of the exhaust valve timing.

Don't forget that a typical automotive turbocharger will run at between 50 and 100,000 RPM when it is most efficient. Any type of mechanical coupling that is attached to the shaft would need to be both heat and high-speed tolerant or else it's not going to last more than a few times around the block.


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## Leebh (Jul 28, 2009)

alpa said:


> crankless engine: try google, it's a kind of engines. Usually huge ones.
> I can not answer your questions, I have no idea. What I'm sure of is that it's technically quite complex.
> Also the energy catched by the turbine is used to compress air, so it's not lost as you seem to think. If you connect another charge to the turbine you'll need more energy to make all that work.


Hi there,

have you considered using a 48V hub motor?


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## scubaet (Jun 27, 2009)

Just some Ideas I had for my Mini a while back. Probably does not do what you are interested in, just random ideas.



















Rear Wheel Drive subframe for the Mini
If you want to power the rear wheels with an electric motor
http://www.minimania.com/web/Item/MT361000/InvDetail.cfm












Can bolt an electric motor to the top.
Can bolt engine into front subframe and install in the back of the mini.
Can have electric in the back run at the same time as the gas engine in the front. Sort of assisting while keeping both separate.
Or use KW motor bolted to the ice to power the electric one in the back.










http://www.theminiforum.co.uk/forums/index.php?&showtopic=128330 

http://www.diyelectriccar.com/forums/showthread.php?p=126742#post126742

http://chargedmini.com/


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