Harlan's Impossible Turbo Build 2
11-28-2016, 05:27 PM
#55
Quick list of current things requiring fixing/testing/install before 8psi:
AC Compressor belt. (Saw the old one as I drove home from work today. Didn't feel like stopping to pick it up.)
Exhaust Leak (Because carbon monoxide is not sexy.)
Ionsensing/Closed loop timing (Either get working well or abandon)
Fuel Pump Pressure control.
Mystery water injection signal (tank draining when it shouldn't)
Anything else I think of.
AC Compressor belt. (Saw the old one as I drove home from work today. Didn't feel like stopping to pick it up.)
Exhaust Leak (Because carbon monoxide is not sexy.)
Ionsensing/Closed loop timing (Either get working well or abandon)
Fuel Pump Pressure control.
Mystery water injection signal (tank draining when it shouldn't)
Anything else I think of.
Last edited by Harlan; 12-20-2016 at 04:51 PM.
Your lady is a good sport 
12-02-2016, 08:54 AM
#58
The injection point is pre-turbo and pre-TB so there is no engine vacuum applied. Also the injector was leak tight with no current applied (at least the last time I checked).
Maybe I've been having so much fun I just haven't filled the tank often enough.
Maybe I've been having so much fun I just haven't filled the tank often enough.
12-05-2016, 07:20 PM
#60
I got closed loop timing working (ish) yesterday. It reads PPP instantly at idle, although it moves around quite a bit (to be expected). The data itself moves around so much I can either have it responsive and fidgety, or very accurate but slow. It ran and maintained PPP at about 45deg in closed loop, dunno if it will remain accurate at higher rpms, but more testing is required.
Still need a lot more programing to get something workable, but at this point I'm moving forward with a pressure vs rpm timing table and let ion sensing slowly adjust. Assuming the data stays good at high rpm. I'm also putting in a timing pull for detonation.
Either way I'm just a little bit of coding away from engine safety.
Also I put together a video I'm calling "The State of the Build Address." It's a quick reference for all the parts of the project.
More to come over the course of this week.
Still need a lot more programing to get something workable, but at this point I'm moving forward with a pressure vs rpm timing table and let ion sensing slowly adjust. Assuming the data stays good at high rpm. I'm also putting in a timing pull for detonation.
Either way I'm just a little bit of coding away from engine safety.
Also I put together a video I'm calling "The State of the Build Address." It's a quick reference for all the parts of the project.
More to come over the course of this week.
12-07-2016, 09:42 AM
#61
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Back then, I was running WI on a very crude set up w/o any solenoid valves between the nozzles and pump. My placement was just prior to the TB and I figured the system was drawing down at a rate much faster than expected. You're running a fuel injector instead of a brass nozzle. . . so, enter the "solenoid valve" I was missing. However, what if the injector isn't sealing properly and is leaking into an area of lower pressure than what is seen behind it? You're only running 4psi right now, so, I wouldn't expect the diffential to be so terrible. I would be interested to know what you're seeing between the compressor and filter, though. . . with all the sensors you have on the car right now, what's one more?!?!
Another thought would be on the effective injection rate. Are you running the same water pressure to both injectors (pre & post compressor wheel)? Calculating flow via PWM would be different for each injector's respected environment under boost, right?
Hopefully, this is all seen as constructive as I truly intend. I'm pretty mentally invested in your build but, admittedly, don't know EVERYTHING you've tested to date. Keep up the great work and progress!
***EDIT - Sorry, apparently I didn't read the very post I quoted close enough! I was thinking you had two injectors for some reason. Looks like everything I said was garbage. . . hehe, back to the corner I go!***
Last edited by rotorbrain; 12-07-2016 at 10:08 AM.
12-07-2016, 09:55 AM
#62
Yeah there will be some preturbo pressure drop, but hopefully not much. I may plumb one of my MAP sensors there to test post filter pressure drop, I won't run it in boost like that (because both sensors have controlling functions) but I could run it NA and test like that.
As for pre vs post injector flow rates, I avoided this problem by only injecting preturbo. The pump puts out about 150psi so even if I had a second injector the difference in flow rates from ATM to even 14psi would be negligible.
Currently working on a detonation based timing limiter, and plugging the ion sensing signal into the knock sensor chip. If it's good enough for the major auto manufacturers it's good enough for me.
I'll keep moving forward on Ion sensing for PPP detection, but no closed loop on the road until I have all the bugs worked out.
As for pre vs post injector flow rates, I avoided this problem by only injecting preturbo. The pump puts out about 150psi so even if I had a second injector the difference in flow rates from ATM to even 14psi would be negligible.
Currently working on a detonation based timing limiter, and plugging the ion sensing signal into the knock sensor chip. If it's good enough for the major auto manufacturers it's good enough for me.
I'll keep moving forward on Ion sensing for PPP detection, but no closed loop on the road until I have all the bugs worked out.
12-08-2016, 05:48 PM
#63
Just spent the day playing with lean burn at idle. And got nothing to show for it but more questions. I just had the car idling at L 10ATDC and T 35ATDC and 16AFR and it was smooth. It shouldn't even run... I'm so confused. And EGTs were going down.
I remember seeing a post about lean burn on the rotary that said subtract timing when you think you need to add timing, and subtract fuel when it seems to rich. But I've never been able to live tune before to see it firsthand before now.
The car shouldn't run at all, it should run badly at best, but it began to purr.
I think I'm onto something.
Edit: Just did it again and confirmed the Ion sensing signal to the knock sensor works...
But it's like the engine enters bizzaro world. Lean is rich, Advanced is retarded, Left is down. I'm trying to get a mental model for what is going on, but this is significantly different from what I thought was going on. More testing is required, but I do think there is usable stuff here.
I remember seeing a post about lean burn on the rotary that said subtract timing when you think you need to add timing, and subtract fuel when it seems to rich. But I've never been able to live tune before to see it firsthand before now.
The car shouldn't run at all, it should run badly at best, but it began to purr.
I think I'm onto something.
Edit: Just did it again and confirmed the Ion sensing signal to the knock sensor works...
But it's like the engine enters bizzaro world. Lean is rich, Advanced is retarded, Left is down. I'm trying to get a mental model for what is going on, but this is significantly different from what I thought was going on. More testing is required, but I do think there is usable stuff here.
Last edited by Harlan; 12-08-2016 at 08:28 PM.
12-10-2016, 01:25 PM
#64
I figured it out. At least I think I did.
The rotary engine works off a few assumptions. One assumption is that the differential pressure between combustion pockets is low as the apex seal passes over the leading spark plug hole. If you retard timing enough you make the combustion pocket that is late in combustion a higher pressure compared to the combustion pocket on the compression stroke. As it passes over the leading plug hole the flame blows from one pocket to the next.
So your engine starts running like this *heavily retarded*, *preignition*, *heavily retarded*, *preignition*. And that matches exactly what I saw, including the increasing amounts of detonation as I retarded timing. There just happens to be a sweet spot on the way down where you start to have preignition but there is only very mild detonation and the engine runs well.
Don't think this discovery has any real value, but it's an oddball find.
The rotary engine works off a few assumptions. One assumption is that the differential pressure between combustion pockets is low as the apex seal passes over the leading spark plug hole. If you retard timing enough you make the combustion pocket that is late in combustion a higher pressure compared to the combustion pocket on the compression stroke. As it passes over the leading plug hole the flame blows from one pocket to the next.
So your engine starts running like this *heavily retarded*, *preignition*, *heavily retarded*, *preignition*. And that matches exactly what I saw, including the increasing amounts of detonation as I retarded timing. There just happens to be a sweet spot on the way down where you start to have preignition but there is only very mild detonation and the engine runs well.
Don't think this discovery has any real value, but it's an oddball find.
12-14-2016, 07:52 AM
#65
I've run out of options trying lean burn at idle with a stock intake configuration. I cant get it over stoich without EGTs and MAF going up, and I've tried massive amounts of timing.
What I'm left with is a handful of possibilities:
It's too cold outside to vaporize the fuel at idle, so it can't lean burn efficiently.
The fuel is burning too slowly to support lean burn.
RPM is too low to support Lean Burn.
The ignition system needs more dwell/multispark to support lean burn.
It will never work, because of _______.
So I'm going to try the simple stuff first. I'm going to try a Hot Air intake and see if I can extend the lean limit. Then I'm going to try a small amount of propane and see if that helps (the propane could bridge the gaps between vaporized gasoline and lead to a smoother burn.) If the propane helps I'll set up a H2 generator and see the effects on the lean burn limit. I may also setup some multispark for Low RPM or a controlled wasted spark.
More results to come.
What I'm left with is a handful of possibilities:
It's too cold outside to vaporize the fuel at idle, so it can't lean burn efficiently.
The fuel is burning too slowly to support lean burn.
RPM is too low to support Lean Burn.
The ignition system needs more dwell/multispark to support lean burn.
It will never work, because of _______.
So I'm going to try the simple stuff first. I'm going to try a Hot Air intake and see if I can extend the lean limit. Then I'm going to try a small amount of propane and see if that helps (the propane could bridge the gaps between vaporized gasoline and lead to a smoother burn.) If the propane helps I'll set up a H2 generator and see the effects on the lean burn limit. I may also setup some multispark for Low RPM or a controlled wasted spark.
More results to come.
12-22-2016, 04:39 PM
#69
Here is a video on why I believe lean burn will work well on the rotary engine, and how you gain efficiency as you go lean. My goal is still 40+MPG.
I done a few different tests so far and I will be posting video and results as I get it edited. So far I've seen a 20% reduction in indicated fuel consumption in idle, but I have not run the test long enough for solid data, nor is data at idle that meaningful anyway. I will be live tuning in cruise when I can get everything set up and recruit a helper.
I done a few different tests so far and I will be posting video and results as I get it edited. So far I've seen a 20% reduction in indicated fuel consumption in idle, but I have not run the test long enough for solid data, nor is data at idle that meaningful anyway. I will be live tuning in cruise when I can get everything set up and recruit a helper.
12-30-2016, 10:16 AM
#73
Brown's gas is a BS term IMO. There is no discernible difference between bottled hydrogen and electrolytic hydrogen except in the case of browns gas there is also electrolytic oxygen with it.
But, NASA has done tests with H2 as a supplemental fuel for lean burn engines. In the 70s they even had a Methanol to hydrogen converted that would run of exhaust heat to allow the engine to run on leaner mixtures of fuel for overall economy.
My plan right now is to use chemically produced hydrogen for small scale testing, and if that is beneficial I'll use electrolytic hydrogen for on the road testing. I don't want to go straight to electrolytic hydrogen because I'm cheap and don't want to waste ~$75 for nothing.
But, NASA has done tests with H2 as a supplemental fuel for lean burn engines. In the 70s they even had a Methanol to hydrogen converted that would run of exhaust heat to allow the engine to run on leaner mixtures of fuel for overall economy.
My plan right now is to use chemically produced hydrogen for small scale testing, and if that is beneficial I'll use electrolytic hydrogen for on the road testing. I don't want to go straight to electrolytic hydrogen because I'm cheap and don't want to waste ~$75 for nothing.
12-30-2016, 11:14 AM
#74
Metatron
iTrader: (1)
Hydrogen works, for sure, just not the stuff produced by those 'Brown's Gas' kits......
Take a bottle of hydrogen in the car and get good (and even lean) results, but trying to produce H2 on the run is a waste of time and effort.
If the H2 is produced onboard, it usually comes from cracking water using silver electrodes in water - with the power coming from the alternator. Nothing in this world is free, and many people make the mistake of discounting the physics involved: each time you convert energy from one form to another, you lose a lot of efficiency.
In this case you use (chemical) gasoline to produce (mechanical) rotation, then use some in the alternator (electrical) to zap water into 'Browns Gas' (chemical) and finally burn it to produce (mechanical) engine rotation.....
Don't bother working out the losses involved with those FOUR conversions - they are close to 99%.
Even using the whole 100 amp alternator output, you'd produce a TINY (milligrams) amount of fuel, but slowing the car's engine by KILOWATTS, and using more fuel.
People have been doing this since Mr. Volta invented his batteries in the 1700's, and it's no closer to producing hydrogen efficiently today.
.
Take a bottle of hydrogen in the car and get good (and even lean) results, but trying to produce H2 on the run is a waste of time and effort.
If the H2 is produced onboard, it usually comes from cracking water using silver electrodes in water - with the power coming from the alternator. Nothing in this world is free, and many people make the mistake of discounting the physics involved: each time you convert energy from one form to another, you lose a lot of efficiency.
In this case you use (chemical) gasoline to produce (mechanical) rotation, then use some in the alternator (electrical) to zap water into 'Browns Gas' (chemical) and finally burn it to produce (mechanical) engine rotation.....
Don't bother working out the losses involved with those FOUR conversions - they are close to 99%.
Even using the whole 100 amp alternator output, you'd produce a TINY (milligrams) amount of fuel, but slowing the car's engine by KILOWATTS, and using more fuel.
People have been doing this since Mr. Volta invented his batteries in the 1700's, and it's no closer to producing hydrogen efficiently today.
.
12-30-2016, 11:25 AM
#75
The question isn't if you can run the car off hydrogen, or if the hydrogen itself will offset some of the fuel consumption.
The question is if supplemental hydrogen will extend the lean burn limit enough to pay for the added load on the engine of a electrolytic cell. I find it doubtful, but I'm willing to do an actual test to find out.
NASA's hydrogen study did show the lean burn limit greatly extended with hydrogen addition, but it was well more than a reasonable sized electrolysis cell could produce. That's why they used methanol cracking as the source, and it caused no parasitic drag on the engine or electrical system. The did not however test smaller amounts of hydrogen, nor did they use variable timing. I think there is enough interest in "brown's gas" and enough potential in the process to do an experiment.
The question is if supplemental hydrogen will extend the lean burn limit enough to pay for the added load on the engine of a electrolytic cell. I find it doubtful, but I'm willing to do an actual test to find out.
NASA's hydrogen study did show the lean burn limit greatly extended with hydrogen addition, but it was well more than a reasonable sized electrolysis cell could produce. That's why they used methanol cracking as the source, and it caused no parasitic drag on the engine or electrical system. The did not however test smaller amounts of hydrogen, nor did they use variable timing. I think there is enough interest in "brown's gas" and enough potential in the process to do an experiment.