Conversion idea, 2L inline 4 -> piston boosted 1.0L 2 banger? Warning....Long thread
 

I had an idea pop into my head a while back and I need someone to help me disprove it, or maybe make it happen, too early to tell yet. Got a few minutes?

Theory:
What if I took my inline 4 banger (VW 2.0L ABA), modified the cam (double lobes 180 degreees out from one another for 2 of the 4 cylinders, intake and exhaust) so that 2 of the 4 cylinders acted like 2 stroke air pumps (basically just intake and exhaust strokes over and over again), I then pipe the "exhaust" (air only in this case) from these 2 cylinders into the 2 normal cylinders as it's intake air, then just run the 2 normal cylinders with fuel and spark, the other 2 would have no spark and no fuel.

The theory in my head would be that you could "convert" 2 of your "air pumps" into a source of forced induction for the other 2, not crazy boost, but something mild as 2 strokes would be completed for every one intake stroke of the normal cylinders. My idea is to turn my 2.0L 4 banger into a mildly boosted 1.0L 2 cylinder that, you guessed it, would get much better miles per gallon, granted slower than stock, but my goal here is mpg not high hp. Any thoughts on my latest brainstorm? Shoot away.

Some details that I have thought over so far: (in no particular order, sorry)
1: I would take the output of the 2 "air pump" cylinders and pump it through the MAF and into the 2 banger intake, that way the computer would know how much air is being fed into the real cylinders.

2: Depending on how you pipe the output to the input, you could even utilyze a front mount air to air intercooler. Granted you lose some of your boost, but at least it would be cooler air.

3: Another thought would be to run gapless rings in the air pump cylinders (the other ones wouldn't hurt either), so that they are more efficient at pumping air (less loss by the rings) and seeing these 2 cylinders would run much cooler as they are not actually "running" it may help as the parts would not expand much. Could also choose which cylinders to do based on heat too, say the middle 2 that way the outer 2 provide heat to the middle 2, but that would depend on which ones are "stroke pairs" for lack of a better term.

4: C2 motorsports has chips for forced inducted 2.0L engines, they run bigger injectors, and use MAF for air used by the motor. Obviously it would take a "special" program to be able to make decisions based on 2 cylinders only, or maybe it wouldn't I am not sure really.

5: I was reading about the old Geo Metro 1.0L 3 cylinder and it was rated at almost 60mpg. Made me think, do I really need 2 liters or just 1 powerful liter, which led to what do I do with the other liter, make it pump air twice as fast as I need it. Other than any pumping losses, it should increase flow with RPMs much like a supercharger does, so it wouldn't need any BOV or wastegate, well in theory at least.

6: The 2.0L crossflow would be a good platform for it due to the intake manifold being 2 parts and a crossflow head would just make the piping that much easier in my mind and less likely to suffer from heat soak.

7: Keep in mind, the air pump pistons will have the exhaust valves open from BDC all the way to TDC (give or take) to avoid having to compress the air much in the cylinder, so it's not like your opening the exhaust valve up while it's under a lot of pressure, just fill it up with air, then push it out. My theory here is if your running these air pumps at twice the speed (2 stroke sort of) of the regular cylinders, then you would produce less than double your air requirement for the other 2 due to inefficiencies, but more than what those 2 would have pulled in on their own (NA).

8: I highly doubt that it would produce more power, not really the goal of this idea. If everything was 100% efficient, in theory your stuffing twice as much air into half the cylinders, so it would be about the same power output, of course nothing is 100% efficient.

9: My thought is, would 2 mildly boosted cylinders produce enough hp & tq to drive the car (everyday use, not a go fast goal)? What kind of economy would it result in? Boosting will increase the efficiency of the boosted cylinders, but will it be a bigger gain than the drag from the 2 air pump pistons?

10: Everyone ranks on the poor 2.slow, don't get me wrong it is in no means a "fast" car, but it goes ok to me. In every day use, I never use more than 50% throttle, am almost always barely on the gas pedal at all, and I have no issues at all getting up to left lane highway speeds in a timely fashion. My thought here is I can live with less HP & TQ in a commuter car as long as I can see the return at the pumps.

11: Say my "system" was 50% efficient, that would mean I have 75% of my HP & TQ (which I could deal with as I've driven much slower cars before), but would that also equate to 45mpg +/-? I'd take that, TDI fuel milage at the cost of regular (hopefully boost stays low enough to avoid running higher octane, but hey, that's what knock sensors are for right?)

12: Think MPG, not 1/4 mile ETs or top speed.
Think, will it be more powerful than the geo metro 1.0L 3 cylinder with all of 53hp and 58 ft/lbs (but rated at almost 60mpg!). The car stock has 115hp and 120ft/lbs, so cut it in half and you've got 57.5hp & 60ft/lbs, there's the geo metro numbers already, now use the 2 dummy jugs to mildly boost the other 2, figure a few simple gains in theory.
10% gain = 63.25hp & 66ft/lbs
25% gain = 71.87hp & 75ft/lbs
50% gain = 86.25hp & 90ft/lbs

13: Realistic turbo setups take these motors (on stock internals as they are forged lower ends) from 100whp +/- in stock form to the 200whp +/- range. So, half the output of a mildly boosted setup, would be right around stock output, based on the fact that your now (under mild boost) making almost 50HP per cylinder, do you really need all 4? Even pulling off 35 to 40 HP per cylinder would give the car plently of power to everyday drive on just 2 cylinders, no?

14: I drove my old rabbit diesel (1.5L NON turbo) for years, it taught you how to maintain momentum as there was no acceleration and it had 49hp and 74 ft/lbs new, and mine had over 250K miles on it. I got 45-50mpg, granted the car was a touch lighter than mine, but you get the idea.

Thank you very much for your time, and your opinions and/or thoughts on my "out of the box" idea are greatly appreciated. Don't feel bad if you can poke holes in my theory, that is why I am asking. If it sounds promising, I have all the spare parts already and may actually try to start tinkering with them.

Just to let you know, I am no "kid" with goofy ideas and no money, I am in my 30s, have a degree in auto tech, work in the software industry, and obviously have way too many thoughts bouncing around in my head. Let me know what you think of my "totally new idea", well as far as I know at least. Maybe I should call it the JoJo cycle engine?

I am no VW expert, more of an all around mechanical guy, 2 strokes, 4 strokes, whatever. Working on a 2 stage air compressor made me think about this (one piston is twice the size of the other running at the same rpms), plus knowing motors and 2 strokes gave me this brainstorm.

I was thinking of a hacked lower intake manifold, a modified tri-y header, and other "swap" type parts to keep the cost down, obviously the cam will cost some dough to design and/or get made, but all other components could be fairly affordable. I am open to any and all ideas. Thanks again for your time. JoJoTheTireMan

Added Thoughts before posting:
I realize the air pump cylinders' valve train would be running at 2x's the engine's RPM, so ti valve springs would be a must. I never rev over 5K anyways, and barely ever over 4K, so getting valve springs that could handle 8-10K RPMS is not out of the question.

Ok, I think this post is long enough at this point, sorry but I had to get this idea out of my head in all it's disorganized glory or else I would have exploded and/or imploded, still not sure on that theory yet either :-( Thanks for your time. JoJo

While it might be crazy
 

There is already a company working on this.

I cannot remember if I read about it here or on The Car Lounge
but there was included a link to their website showing cutaways
of the motor in action and of course asking for support (money)
to help comercialize.

If I recall correctly, it utilized siamesed cylinders to do just what you are suggesting. However, would this not be another form of supercharging?

I think there would be less efficiency losses through friction from using either a supercharger or turbocharger.

If anyone has any info on the company working on something similar or a link it would be greatly appreciated.

Indeed, it would be another form of supercharging, that is the idea.

I also agree that a turbo or true supercharger would be more efficient, but I don't want more HP/TQ, I want more mpg out of my existing powerplant, so my idea was to shut off half the motor and turn it into a supercharger of sorts to help the remaining 2 cylinders make enough power to operate the car. Going on the theory that a boosted 1.0L 2 banger would use less fuel than a NA 4 banger yet still make enough power to keep up with the traffic. Never mind the fact that I wouldn't need to spend thousands on a supercharger/turbo kit. It just seems like a good way to effectively reduce the displacement of the motor, and hopefully it's fuel consumption.

I like your thinking
 

One of the other guys here is working on that idea also(Diesel John?)
A brazillion years ago, when I was overseas for the Army, I read in one of the Maint. Manuals about a kit the USArmy had for converting a four cyl Jeep (M151) to a two cyl air compressor.
Basically doing what you have described.
Two outer cyl's, #1&4, used for gas engine to drive the unit.
Two inner cyl's, #2&3, used for air pump.
However the Army setup used one way check valves (iirc) for the compressor cyl's.
So the intake and exhaust were split to allow the engine to run off of the two end cyl's.
Then the valve train was modified to keep the valves open during operation (No worry about pistons smacking the valves, these were very loose engines), and check valves put in place to allow air into the two center cyl's through the intake, so it would be filtered, and out the exhaust. then piped to a pressure vessel and used to run all manner of pneumatic tools.
Hope you can make it work.
BTW my 1 litre has very little torque.(it is more than adequate for a tiny car)
your 1 litre should have quite a bit more
bigger pistons X
longer stroke =
more torque:D
Schultz.

If anyone is working on a similar idea please post or contact me. Thanks
Indeed, I could see that working with a stepped up idle speed and the jeep parked, why not use the engine to make compressed air to run tools, afterall it is basically an air compressor anyways. I just have a different use for the compressed air :-)
I was thinking about using a type of reed valve on the output of the compressor cylinders to eliminate any reverse flow and to smoothen out the pulse effect of the compressor cylinders. Could even replace the valves with one way reed style valves to reduce some of the valve train friction as I will no longer have a a power stroke per se.
Keep the comments coming, any and all feedback is greatly appreciated. Thanks again....JoJotheTireMan

My thoughts are in BOLD take them as you may


[QUOTE=JoJotheTireMan;24002]

Some details that I have thought over so far: (in no particular order, sorry)
1: I would take the output of the 2 "air pump" cylinders and pump it through the MAF and into the 2 banger intake, that way the computer would know how much air is being fed into the real cylinders.Good Idea maybe a standard supercharger would work better, but would require a smaller engine

2: Depending on how you pipe the output to the input, you could even utilyze a front mount air to air intercooler. Granted you lose some of your boost, but at least it would be cooler air.Use a liquid to air charge cooler, keep the plumbing as short as posable, investigate the idea of warmer air for efficiency

3: Another thought would be to run gapless rings in the air pump cylinders (the other ones wouldn't hurt either), so that they are more efficient at pumping air (less loss by the rings) and seeing these 2 cylinders would run much cooler as they are not actually "running" it may help as the parts would not expand much. Could also choose which cylinders to do based on heat too, say the middle 2 that way the outer 2 provide heat to the middle 2, but that would depend on which ones are "stroke pairs" for lack of a better term.Gapless Lower tension rings, no need for oil squirters (if equipped) either which 2 to pick would be determined by which 2 running would still run best

4: C2 motorsports has chips for forced inducted 2.0L engines, they run bigger injectors, and use MAF for air used by the motor. Obviously it would take a "special" program to be able to make decisions based on 2 cylinders only, or maybe it wouldn't I am not sure really.probably a need for complete fuel/ spark control on a project like this, i'd look in to standalone ECU's Mega squirt is cheap, works well. Otherwise I'd throw the factroy maf on the intake of the 2 compressor cylinders, emove 2 injectors, and give it a go

5: I was reading about the old Geo Metro 1.0L 3 cylinder and it was rated at almost 60mpg. Made me think, do I really need 2 liters or just 1 powerful liter, which led to what do I do with the other liter, make it pump air twice as fast as I need it. Other than any pumping losses, it should increase flow with RPMs much like a supercharger does, so it wouldn't need any BOV or wastegate, well in theory at least. if the throttle body is before the air compressor there is no need for a BOV, a system like this should work correctly with out a wast gate (essentially a positive displacement supercharger)

6: The 2.0L crossflow would be a good platform for it due to the intake manifold being 2 parts and a crossflow head would just make the piping that much easier in my mind and less likely to suffer from heat soak.I take it crossflow indicates that intake and exaust are on opposite sides of the head?

7: Keep in mind, the air pump pistons will have the exhaust valves open from BDC all the way to TDC (give or take) to avoid having to compress the air much in the cylinder, so it's not like your opening the exhaust valve up while it's under a lot of pressure, just fill it up with air, then push it out. My theory here is if your running these air pumps at twice the speed (2 stroke sort of) of the regular cylinders, then you would produce less than double your air requirement for the other 2 due to inefficiencies, but more than what those 2 would have pulled in on their own (NA).Umm, I believe you

8: I highly doubt that it would produce more power, not really the goal of this idea. If everything was 100% efficient, in theory your stuffing twice as much air into half the cylinders, so it would be about the same power output, of course nothing is 100% efficient. could add an old mr2 clutch type supercharger to gain back your needed hp, if you need them

9: My thought is, would 2 mildly boosted cylinders produce enough hp & tq to drive the car (everyday use, not a go fast goal)? What kind of economy would it result in? Boosting will increase the efficiency of the boosted cylinders, but will it be a bigger gain than the drag from the 2 air pump pistons?It would be driveable, I don't know if it would be acceptable to you, or not. take a look at the power/ performance of the forkenswift, it is driveable



11: Say my "system" was 50% efficient, that would mean I have 75% of my HP & TQ (which I could deal with as I've driven much slower cars before), but would that also equate to 45mpg +/-? I'd take that, TDI fuel milage at the cost of regular (hopefully boost stays low enough to avoid running higher octane, but hey, that's what knock sensors are for right?)I don't know about where you live, but here the price "premium" for premium isn't that large % wise

12: Think MPG, not 1/4 mile ETs or top speed.
Think, will it be more powerful than the geo metro 1.0L 3 cylinder with all of 53hp and 58 ft/lbs (but rated at almost 60mpg!). The car stock has 115hp and 120ft/lbs, so cut it in half and you've got 57.5hp & 60ft/lbs, there's the geo metro numbers already, now use the 2 dummy jugs to mildly boost the other 2, figure a few simple gains in theory.
10% gain = 63.25hp & 66ft/lbs
25% gain = 71.87hp & 75ft/lbs
50% gain = 86.25hp & 90ft/lbs
Why not swap in a 1.0 metro motor? put an MR2 Clutch super charger on it, spray some water/ methanol in it when boosting so you can run 87 octane?

13: Realistic turbo setups take these motors (on stock internals as they are forged lower ends) from 100whp +/- in stock form to the 200whp +/- range. So, half the output of a mildly boosted setup, would be right around stock output, based on the fact that your now (under mild boost) making almost 50HP per cylinder, do you really need all 4? Even pulling off 35 to 40 HP per cylinder would give the car plently of power to everyday drive on just 2 cylinders, no? all depends on your expectations

14: I drove my old rabbit diesel (1.5L NON turbo) for years, it taught you how to maintain momentum as there was no acceleration and it had 49hp and 74 ft/lbs new, and mine had over 250K miles on it. I got 45-50mpg, granted the car was a touch lighter than mine, but you get the idea.
I drove my TDI boost free for a few days, I know the feeling


Thank you for throwing this idea out there, I'd like to see it tried, but I would do it low budget as a test.

Indeed, which is why I am trying to reuse as many parts as I can, or even use parts from different models of VWs as they have lots of semi-interchangeable parts among models and/or years. Other than MegaSquirt (which I may be able to avoid if I could get the stock ECU programmed for my application) the only costly part of this idea would be a custom cam, which could be a modified stock cam, or even maybe just a double valve actuater, a lever design that would open the valve as the cam lobe goes around the top of it's travel, then open it again the normal way on it's way around the bottom of it's travel circle. Could even get into using different pistons for the air pump jugs, something in a higher compression ratio to effectively move more air.

Like I said, I am open to any and all suggestions.

Lots of things can be designed a better way from the get go, but that way is super costly. I am hoping to have a "kit" so to speak that can be retrofitted to existing vehicles. More usefull from a cost perspective, to me at least as I am not exactly going to go into business designing new powerplants from scratch anytime in the near future.

Thanks for the feedback. JoJotheTireMan

Welcome
Where do I start?
Good technical writing job by the way.
Dido everything said so far.
Posts are a great place to get rid of those annoying inventions.
Usually if someone tells me it wouldn't work, I try it.

Probably the one of most efficient piston engines would be a slow turning, one cylinder diesel under full load 100% of the time. (diesel/electric)

Yes, IMHO, your idea will function.
In the big picture, IMHO, friction, pumping losses, etc. will eat up any possible gains. I am by no means an expert on engine cycles.

You can advance search on a user name and see all the posts a user has started.

I got your email, and what i am going to do is take out #2 & #3 pistons from a vw diesel. Take out the valve actuating buckets. Cover the oil holes in the crank with a hose clamp. Pipe the fuel from 2 & 3 to a flow measuring device and return that fuel to the tank. Use my gear shift lever a lot more. Also i am trying to figure out how run an alternator with my exhaust gas. So i can eliminate the the accessory drive belts. I don't want to hyjack your post.

Questions.
What type of fuel injection do you have?
Will the cam clear the valve stem if you take out the buckets? (or is that boo-kay:))
Would an umbrella type valve seal keep oil from getting sucked down the deactivated valve stems?

I don't know if the umbrella seal would prevent all oil from getting down the valve stem, but if the valves are never being opened in your case then there is no suction at those valve stems. In my case, yes I will have oil being sucked into my air pumps, small amounts, but yes it would be sucked down I would imagine, but a little oil never really hurt anything as just about every motor out there burns some oil to some degree.

I do like your idea, and I could go that route with a gas motor too, but I have a funny feeling that it just wouldn't produce enough HP/TQ to run smoothly and/or be very usefull in every day driving. But you may be able to get away with it on a diesel due to the increased TQ at lower RPMS. Best of luck with your experiment, JoJo

Well, first thought on this is a vortex supercharger. This is basically half of a turbo (output side) bolted to a pulley which is run by the accessory belt. If you did the opposite and ran the driven half of a turbo and use a pulley to drive the alternator.

Other ideas for turning the alternator:
Both of these thoughts would require forward motion to work, but I think the battery could handle things when your stopped.
One idea would be to weld/bolt a pulley to one of your driveshafts closest to the trans to avoid belt deflection due to suspension travel and make a bracket to hold the alternator and maybe a belt tensioner. All in all it will still be driven by the motor in this case, but would possibly make idling more efficient, which on a diesel is almost a mute point.
The other idea would be to duct air in from the grill/hood to spin a compressor/fan of some kind which in turn would spin your alternator, it may add a little to the aerodynamic drag but would allow the removal of the accessory drive belt system, well assuming that your water pump is timing belt driven.
Both of these would benefit from EOC as your still spinning the drive shafts and your still plowing through the air even when your coasting with the engine off.
Again, best of luck. JoJotheTireMan