Author Topic: Treadmill Dyno  (Read 164051 times)

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Mary B

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Re: Treadmill Dyno
« Reply #495 on: February 09, 2015, 05:34:06 PM »
Wonder if a timing chain might be better than that belt(looked like a belt anyway)? Looked a bit sloppy.

taylorp035

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Re: Treadmill Dyno
« Reply #496 on: February 09, 2015, 07:13:58 PM »
My current engine uses a #25 chain and a 2:1 ratio for the drive to the rotary valve.  Version 1 used a Kevlar stranded timing belt and we broke several nylon stranded belts due to the high loads from the aggressive cams that held the valve down.




taylorp035

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Re: Treadmill Dyno
« Reply #497 on: February 21, 2015, 02:02:47 PM »
Finally hooked the rotary valve engine up to the dyno and was able to do two runs.  Both were at full throttle.  The first one was just to measure peak horsepower, which yielded 2.4 shaft horsepower at ~3800 rpm.  Not bad considering the stock engine is only rated for 1.5 hp.  The second run, we did a fuel economy test and it yielded 13.4% efficient at 2.3 hp.  That kind of efficiency is comparable to a stock 3.5 hp briggs.  Both the peak power and efficiency numbers could of been higher due to a pretty large groove that was forming in seal and was causing it to leak.  After those runs, it was misfiring and not holding idle very well... so it looks like it is time build a new seal and possibly a new valve.  The current "valve overlap" between the intake and the exhaust is 5 degrees.  I plan on making that a bit more aggressive.  The question is how much.  I also need to question the heat transfer ability between the seal and the head, as it was pushing ~330F after the dyno runs.

SparWeb

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Re: Treadmill Dyno
« Reply #498 on: February 21, 2015, 08:37:38 PM »
That's excellent Taylor! 

The production of 60% more power implies the production of more heat (even considering any improvement in efficiency).  Many parts could be running hotter than they did, even the stock components.
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taylorp035

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Re: Treadmill Dyno
« Reply #499 on: March 11, 2015, 07:05:24 AM »
https://www.youtube.com/watch?v=RjvYnzo0Qe0

We designed and machined a new seal, now with 36 degrees(crankshaft) of valve overlap between the intake and exhaust vs the previous 11.  Now it sounds more like a performance oriented engine and shoots a few more flames.  It definitely seems to have more power,  and we can't wait to put it back on the dyno.  We also swept the shape of the port for better flow on the intake stroke.

Last night, we replaced the hoses and fittings on the fuel system so it stopped leaking, so we tried to use all the gas in the tank.  Managed to get the center of the valve up to ~550 F, at which point it decided it didn't want to idle much more.  I think the gooey oil that cakes itself to the valve and seal started to melt and caused more leaks.  The intake gases do a good job of cooling the one side of the valve and the part between the chain and the seal was about 350F.

« Last Edit: March 11, 2015, 07:14:00 AM by taylorp035 »

taylorp035

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Re: Treadmill Dyno
« Reply #500 on: October 30, 2016, 11:14:46 AM »
Bringing back this thread to show off the next stage of the rotary valve engine development!

Now in a 1999 BMW 328is 2.8L inline 6 engine.  A first in many respects, including converting a modern production car, an Inline 6, and a BMW. It has some fun features including muffler bearings, exhaust bearing coolant, coolant running through a floating seal around the sparkplug, contra-rotating valves, 6 velocity stacks with no obstructions going right into the cylinder, custom double bevel gear box with homemade "cam lobe", multi-tiered oiling system, and a fully re-mapped cooling system that has many clear hoses.

Over 700 components, fully integrated into the stock engine bay.......... so bolts right up to the exhaust, all the sensors and hoses and stock intake.  No programming of the ECU has taken place yet (many people said this would never work).  We machined about half the components ourselves to save cost, but the bigger ones exceeded the capacity of our tools so they had to be sent out.

I'm getting really close to taking it back to the dyno to see how she fairs.  Still working out some kinks, but it has over an hour of run time on it and about 3 miles of hard driving in my back yard and up and down my driveway.  There have been moments where it seems like it has more power than the stock engine.  Sealing seems to be much better than the ego-kart engines and it has good compression and spark.

And I have to give some congratulations for BMW making such a robust starter motor.....

https://www.youtube.com/watch?v=GdmzrVj9n7s

https://www.youtube.com/watch?v=_3egpax5sZI

https://www.youtube.com/watch?v=W7x-3fukxhE

https://www.youtube.com/watch?v=gVU1jK0yono

https://www.youtube.com/watch?v=BYpECSaNMhE

https://www.youtube.com/watch?v=10xnE8W3Qe0

https://www.youtube.com/watch?v=-8iTKxYdLb4

« Last Edit: October 30, 2016, 11:20:00 AM by taylorp035 »

SparWeb

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Re: Treadmill Dyno
« Reply #501 on: November 04, 2016, 01:30:51 AM »
HAha!
If there was ever a reason for your "check engine" light to be on...

I'm glad I clicked on the last vid first:  Smoke and fire and blue flashes, oh my!
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
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taylorp035

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Re: Treadmill Dyno
« Reply #502 on: January 29, 2017, 09:44:23 PM »
A picture of the engine bay when it was a bit warmer outside.  It's waiting for timing belt #4 to be delivered and installed. 


taylorp035

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Re: Treadmill Dyno
« Reply #503 on: April 04, 2021, 10:37:36 PM »
Pulling this thread back to the surface with a new video on my rotary valve BMW engine.  This winter we designed, machined and installed some inserts in the floating seals to reduced the effective valve opening duration to something closer to a muscle car than a 9,000 rpm drag racing engine.  It's much quieter (but not too quiet...) and now idles on all cylinders.

https://youtu.be/NR6hlyy6VsY

SparWeb

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Re: Treadmill Dyno
« Reply #504 on: April 06, 2021, 12:18:43 AM »
Still fascinating to see the progress you've made on this.
Are you still working on the valve port geometry?
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
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taylorp035

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Re: Treadmill Dyno
« Reply #505 on: April 08, 2021, 09:33:52 PM »
Quote
Are you still working on the valve port geometry?
The new inserts should be the final answer.  It's now down to adjusting the advance of the valves relative to the crankshaft and ECU tuning.

Some photos of the new inserts.  We did lap the inserts into the half pipe shape.  Then we thermally fit them into each of the floating seals with a very, very aggressive 0.003" interference + some green Permatex locking compound.

14010-0

14011-1


Here's the valve for scale.  The ports are 1.2" wide and 2" long.  This was when we had to replace the muffler bearing (yup....).  On the intake side, it's usually possible to replace them without removing the valve.  The exhaust has a harder life because we often pound the valve through with a hammer and it's exposed to hot temperatures when the cooling loop isn't working and still elevated temps when it is.
14012-2

SparWeb

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Re: Treadmill Dyno
« Reply #506 on: April 09, 2021, 12:27:02 AM »
I don't remember everything you came up with to make a solid seal (this is a LOOONNNG thread, now!) but I know you tried a lot of things. 

Do you have any estimate how much power this sucks from the engine, compared to a cam/valve system you took off?
(not that it really matters - the whole idea more than makes up for nit-picky stuff like mechanical efficiency)

Have you worked on any methods to advance/retard valve timing?

How much does brass like being a cylinder head?
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taylorp035

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Re: Treadmill Dyno
« Reply #507 on: April 11, 2021, 10:26:55 AM »
Quote
"I don't remember everything you came up with to make a solid seal "
- There's 4 parts to sealing this.  Two rotary shaft seals.  The half-pipe floating seal is pushed up during the combustion event for increased contact pressure.  And a spring loaded top seal so the vacuum from the intake manifold isn't lost when the intake port on a particular valve is up above the half-pipe shape.  In addition, we also made some silicone pieces to cover the whole head to help reduce the smoke that escapes from all the joints.

Quote
Do you have any estimate how much power this sucks from the engine, compared to a cam/valve system you took off?
- Not on this engine, but the one we did in college on a Briggs and Stratton, yes.  There has been other people who have estimated that the rotary valve system takes less to drive than a camshaft, but I think that's probably if everything is working well.  It's not too bad, so I would say the savings or penalty isn't large.

Quote
Have you worked on any methods to advance/retard valve timing?
-  Yes, there is a taper fit #40 chain sprocket coming out of the bevel gear box that is adjustable within ~2 minutes.  This is an important part of the design since you can really tell the difference depending on where you have it set or if it slips.

If you really want to scratch your head, we built another Briggs and Stratton rotary valve head that allows you to change the rotating velocity of the valve at different parts of the 4-stroke cycle while it's running.  This effectively allows you to change the duration of the intake and exhaust events.  I have a video of it running and it actually works quite well.  We are upgrading it right now to a 5 hp engine for a go-kart and making it more robust.  There is a lever you can pull to change the timing.

Quote
How much does brass like being a cylinder head?
- Haven't had any issues yet with the brass.  It holds up well to the rotating surfaces.  I've had the engine fairly hot with no coolant flow and also I've driven it ~ 8 miles straight without stopping.  So far it has about 105 miles on it over the last 5 years.  Hopefully that number goes up here now that we have it back together and it's stopped snowing.