My internal combustion engine is more efficent than 30%

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The discussion centers on the thermal efficiency of a modified 2000 cc spark-ignited engine, with claims of achieving 50% efficiency at idle, which is contested by other forum members. The original poster cites fuel consumption measurements and compares them to a similar engine's idle fuel usage, seeking validation for their calculations. Critics argue that idle efficiency is effectively zero due to lack of mechanical work and emphasize the need for controlled testing to accurately measure efficiency. They also highlight the significant potential for error in the original poster's estimations and suggest using a dynamometer for reliable results. Overall, the conversation underscores the complexities of measuring engine efficiency and the importance of precise data collection.
  • #31
jarednjames said:
What are you using to read fuel use? I hope it's not the cars fuel gauge.

No the fuel gauge only has a resolution on about 2.5 L.

I park my car wait about 1 min then fill it up to the top of the filler pipe, parking as close as I can to the same spot on the service station driveway.
 
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  • #32
mender said:
Better answer: stop expecting that engine to survive. It won't.

Let me save you a lot of time and money: your concept is not going to succeed. You're chasing a dead end, and your methodology won't allow you to see that.

Ok if a compression ratio of 12.5:1 is too high then my spark plugs should destroy themselves from overheating and probably melt pistons too but I had carbon build up.

See my video for what happened to my plugs and my carby was running fine. I killed the bearings and crankshaft in about 2-3 weeks due to the timing needed above 3000 RPM, I ended up using 20" and 30" bearings on the conrods, I then lowered the compression and drove it for another 7-8 months before it died.
http://www.youtube.com/watch?v=XnwJuNbvULY"

"survive" it would be a lot better if some one had not put silicon in the engine oil.
 
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  • #33
smokingwheels said:
Ok 1 problem its 5 HP not kw so I redid the numbers, If you want the links to my evidence please let me know and I will post them.

Output: 5 HP = 3.7284kw for 1 min = 223 kj energy
Input: My best is 10cc of fuel/min 0.01 * 34.8 =.348 MJ = 348 kj

So my indicated thermal efficiency is 223 / 348 = 64%
I have it on video on youtube

I did a 40 min test and measure in 2008 and the average was 13.66 cc/min

Output: 5 HP = 3.7284kw for 1 min = 223 kj energy
Input: my average 13.66 cc of fuel/min 0.01366 * 34.8 =.475 MJ = 475 kj

So my indicated thermal efficiency is 223 / 475 = 49%

I did a more recent test and used approx 15 cc/min

Output: 5 HP = 3.7284kw for 1 min = 223 kj energy
Input: my best is 15 cc of fuel/min 0.015 * 34.8 =.522 MJ = 522 kj

So my indicated thermal efficiency is 223 / 522 = 42%

so its dropped off a bit when I have some money to spare I will rip it apart and look at what's gone on

Note: I used 5 HP not 5kw because that's what is quoted around the traps for a 2L 4 cylinder engine.
I have even been quoted 30cc/min just to idle as well for a normal 4 cylinder but my program puts that down to 20 cc/min for 5 HP.

Thanks for your time Chriss

In the above calculations the 10cc/min was at 650 rpm and the 13.66 cc/min was 830-850 rpm.
The corrected (guessed within 5% of full scale ) fuel consumption for 750 rpm is 11.5 cc/min

So I think I did 340 km on 14L one night when engine was in good condition.

14L used, 340km distance, 80 km/h speed and approx 2200 RPM
4.25 hours * 60 = 225 min
14L / 285 min = 62.22 cc/min
engine used 11.4 kw of fuel to go at 80km/h

Plug fuel consumption into turbocalc = Engine VE%@80 km/h = 28.5%
How much is this different to a normal car with a 2L engine and 1120kg dry mass?
Can you work out engine efficiency from this or not?
Remember I have old technology eg carby
 
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  • #34
smokingwheels said:
Ok if a compression ratio of 12.5:1 is too high then my spark plugs should destroy themselves from overheating and probably melt pistons too but I had carbon build up.

See my video for what happened to my plugs and my carby was running fine. I killed the bearings and crankshaft in about 2-3 weeks due to the timing needed above 3000 RPM, I ended up using 20" and 30" bearings on the conrods, I then lowered the compression and drove it for another 7-8 months before it died.
http://www.youtube.com/watch?v=XnwJuNbvULY"

"survive" it would be a lot better if some one had not put silicon in the engine oil.

How much oil was the engine burning at the time? I doubt the carbon on the plugs was from an overly rich mixture, agreed?

Knocking the bearings out is a sure sign of detonation, which is going to happen if you try to run high compression with low octane fuel; no surprise there.

Silicon?
 
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  • #35
smokingwheels said:
Plug fuel consumption into turbocalc = Engine VE%@80 km/h = 28.5%

What version of Turbocalc are you using?
 
  • #36
mender said:
What version of Turbocalc are you using?

Version 2.2
 
  • #37
mender said:
How much oil was the engine burning at the time? I doubt the carbon on the plugs was from an overly rich mixture, agreed?

Knocking the bearings out is a sure sign of detonation, which is going to happen if you try to run high compression with low octane fuel; no surprise there.

Silicon?

The engine had no visible smoke from exhaust.
Yes the mixture was ok eg definably no black smoke or chugging from exhaust.

Silicon. my 2nd engine has had silicon put in it I had to remove the head to unblock the oil passage so that the cam could get oil again but it also damaged the bearings.
The plug of silicon was about 25mm long.
 
  • #38
smokingwheels said:
Version 2.2

I have Version 2.3; where are you plugging in the numbers?
 
  • #39
smokingwheels said:
The engine had no visible smoke from exhaust.
Yes the mixture was ok eg definably no black smoke or chugging from exhaust.

Silicon. my 2nd engine has had silicon put in it I had to remove the head to unblock the oil passage so that the cam could get oil again but it also damaged the bearings.
The plug of silicon was about 25mm long.

Silicone, as in RTV, not the metal silicon, right?

If there was no oil burning, then the carbon buildup is from incomplete combustion, i.e. not all the carbon atoms are combining with oxygen to form CO2 or even CO. You're wasting fuel energy, likely by having such late ignition timing to compensate for the excessive compression.

You'd be better off reducing the compression ratio and concentrating on increasing turbulence (swirl, quench, etc.) to get a better burn and make the engine less sensitive to detonation and plug fouling. You're concentrating too much on the expansion part of the cycle and giving up combustion efficiency - and damaging your engine. Also it appears that you consider ignition timing before TDC as evil; some will always be needed to get the mixture to burn and produce peak pressure at the right time but that can be reduced by increasing the burn rate (i.e. turbulence as mentioned).
 
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  • #40
smokingwheels said:
How much is this different to a normal car with a 2L engine and 1120kg dry mass?
Can you work out engine efficiency from this or not?

I know you have limited resources but to get some usable accuracy you should find some way of calculating the hp needed by your car at your test speed. You'll also need to keep good records of the weather conditions; a small change in wind direction and speed during a test will invalidate that test by skewing your readings. Otherwise you're only guessing.

How important is this to you?
 
  • #41
mender said:
I have Version 2.3; where are you plugging in the numbers?

Go to the EFI section put in the kw then number of injectors 1 then mixture 14.7
Adjust the kw until you have matched you measured fuel flow.
Write down the kw then go to the turbo power enter engine config.
Set Boost pressure to 0 and Compressor efficiency to 2(has to be bigger than 0 or program error), turn off intercooler.
Now calculate engine and adjust VE% until you have the correct kw you found in the EFI section.
I have measured 2 fuel flows at different rpm eg 650 and 850 and its about 5% low but that probably because I changed the rpm without increasing VE%, this figure would have to increase with rpm to allow more air/fuel into the engine the error could also be my carby is running 5% rich.

Just had a coffee...
Once you know VE% you can then workout your change in rpm = kw then put kw into EFI and it will give you the fuel required cc/min from that eg .56kw = 3cc/min / 200 rpm= 0.015 cc/min per rpm for engine overhead. I would have to measure mine at several higher rpm points and see if it works out but for now its good enough.
The starter motor is rated at 1kw and drives 300 to 400 rpm on the engine, I would have to test and log the peak speed of the engine cranking with no spark to confirm that though but that is something I can do.
 
  • #42
mender said:
I know you have limited resources but to get some usable accuracy you should find some way of calculating the hp needed by your car at your test speed. You'll also need to keep good records of the weather conditions; a small change in wind direction and speed during a test will invalidate that test by skewing your readings. Otherwise you're only guessing.

How important is this to you?

Thanks for the advise I am getting better since I found the http://www.weatherzone.com.au/"

My project is very important because my first engine would have been needed to be fired After Top Dead Center under load.
Here is a plot of my engine after I lowered the compression to ~8:1 from 12.5:1.
You will notice that the peak timing is reached by 1500 rpm which is normally 3000 rpm for my type of engine. After 1500 rpm the timing takes a dive back to ~20 deg BTDC this normally is about 2-3 deg up to the red line rpm. The values were tuned 1 step at a time over the rpm range so that most of them didn't knock, I did not understand much about tuning in 2003 because later on I found you got more grunt if you backed the timing off a little more and my programs had improved as well.
coila1.gif
 
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  • #43
smokingwheels said:
Thanks for the advise I am getting better since I found the http://www.weatherzone.com.au/"

My project is very important because my first engine would have been needed to be fired After Top Dead Center under load.
Here is a plot of my engine after I lowered the compression to ~8:1 from 12.5:1.
You will notice that the peak timing is reached by 1500 rpm which is normally 3000 rpm for my type of engine. After 1500 rpm the timing takes a dive back to ~20 deg BTDC this normally is about 2-3 deg up to the red line rpm. The values were tuned 1 step at a time over the rpm range so that most of them didn't knock, I did not understand much about tuning in 2003 because later on I found you got more grunt if you backed the timing off a little more and my programs had improved as well.
coila1.gif

Are these actual measured values or approximations you've generated?
 
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  • #44
mender said:
Silicone, as in RTV, not the metal silicon, right?

If there was no oil burning, then the carbon buildup is from incomplete combustion, i.e. not all the carbon atoms are combining with oxygen to form CO2 or even CO. You're wasting fuel energy, likely by having such late ignition timing to compensate for the excessive compression.

You'd be better off reducing the compression ratio and concentrating on increasing turbulence (swirl, quench, etc.) to get a better burn and make the engine less sensitive to detonation and plug fouling. You're concentrating too much on the expansion part of the cycle and giving up combustion efficiency - and damaging your engine. Also it appears that you consider ignition timing before TDC as evil; some will always be needed to get the mixture to burn and produce peak pressure at the right time but that can be reduced by increasing the burn rate (i.e. turbulence as mentioned).

Yes Black RTV was found...

In my first engine it had 2 compression ratios 12.5:1 and 8:1.
I had plenty of power with the high compression engine but the spark plugs only lasted 3-4 days before shorting out with carbon.
In the low compression engine I was still replacing spark plugs every 2 months and it was on the edge of knock in certain rpm ranges but the correct Vacuum advance was not discovered until 2006.
I wonder how retarded you would have to run an engine to knock the plugs out in 150-200 km, I bet you would not be able to create wheel spin when turning a corner either.

I personally think turbulence is the wrong way to go we are dealing with an analog device.
I think turbulence=distortion.

What I have done seems (think? well my timing is way different) it changes the thermal expansion rate eg fire a approx square engine (Bore * stroke =) 65 Deg BTDC and see it it still runs forward without knocking and with a compression ratio ~10.5:1.
I found this site last night and plugged in the values for my engine (Green) and a normal engine (red) the result. I am not sure what I am looking at yet but when I fire 65 BTDC all my thermal energy is used up and the highest pressure of that eg the complete combustion cycle is very near TDC, I think this should cause a knock but it only runs a bit rough.
CumulativeHeatReleaseFraction.jpg


I think timing Before TDC is EVIL because you are compressing a rising energy eg you have to waist energy to compress the expanding gases instead of compressing a gas..Hope that makes sense.

Increasing burn rate hmm I think that would be like increasing distortion in my audio amp = not very nice. I could be wrong though.
 
  • #45
This is good stuff:
mender said:
I know you have limited resources but to get some usable accuracy you should find some way of calculating the hp needed by your car at your test speed. You'll also need to keep good records of the weather conditions; a small change in wind direction and speed during a test will invalidate that test by skewing your readings. Otherwise you're only guessing.

How important is this to you?
I have a $150 gadget that reads out my engine's operating parameters in real-time. On my way to/from work, there is a relatively flat 1-mile stretch of highway that has a very slight drop followed by a very slight rise, with a total of about a 15' difference in elevation from one end to the other. I've done loose tests with my car, but a more rigorous test method is not very difficult:

1. Make sure your fuel flow readout is calibrated. They are lookup-table based, not actual measurements.
2. Record the weather conditions. These are very important. Counter intuitively, I have found my car to be substantially more efficient at warm temperatures (70F) than cold temperatures (30F).
3. Make sure the car is fully warmed-up. This makes a surprisingly huge difference.
4. Enter the straight at a pre-chosen and set speed on your cruise control. For better results, run in both directions and average them.
5. Have a friend copy down the fuel flow rate every few seconds - or better yet, some products will record the data for you on a smart phone or laptop.
6. Average the fuel flow and calculate the input power.

Now you won't have a good baseline because you've already made some modifications, but since a typical car runs at somewhere around 30% efficiency, you should notice a massive difference between your car's fuel flow rate an the rated fuel efficiency of your car. Note, depending on your speed, you may notice a 10% better fuel economy just due to the fact that you are running at constant speed. EPA tests are run on a course with variable speed. Ie, my car is rated at 32, but I've seen as much as 35mpg - a difference of just under 10%.
 
  • #46
jarednjames said:
Are these actual measured values or approximations you've generated?

From what I can remember there values out of the program.
but I had a search thru my harddisk collection and found this I think its what I used because I would have to setup my program again eg feed in simulated rpm/calibration pc to check the timing accuracy.
The file is called coilone which I shortened to coil1 on the graph.

Anyway here is a copy of the mechanical advance from the program.

REM mec advance
DATA 5,5,5,5,5,5,5,5,5,5 : REM 250

DATA 5,5,10,10,10,10,10,10,10,10 : REM 500

DATA 10,10,10,10.2,10.4,10.6,10.8,11,11.3,11.6 : REM 750

DATA 11.9,12.2,12.5,12.8,13.1,13.4,13.7,14.4,15.5,16.5 : REM 1000

DATA 19,21,21.5,23.5,24.5,25.5,26.7,27.8,28.5,29 : REM 1250

DATA 29.5,30,30.1,30.2,30.3,30.4,30.5,30.6,30.7.30.8 : REM 1500

DATA 30.9,31,31,31,31,31,31,31,31,30.9 : REM 1750

DATA 30.8,30.7,30.6,30.5,30.4,30.3,30.2,30.1,30,29 : REM 2000

DATA 28,28,28,28,28,28,28,28,28,28 : REM 2250

DATA 27.8,27.5,27.2,27,26.8,26,22,22,22,22 : REM 2500

DATA 22,22,22,22,22,22,22,22,22,20 : REM 2750

DATA 20,20,20,20,20,20,20,19,19,19 : REM 3000

DATA 19,19,19,19,19,19,19,19,19,19 : REM 3250

DATA 19,19,19,19,19,19,19,19,19,19 : REM 3500

DATA 20,20,20,20,20,20,20,20,20,20 : REM 3750

DATA 20,20,20,20,20,20,20,20,20,20 : REM 4000

DATA 21,21,21,21,21,21,21,21,21,21 : REM 4250

DATA 21.5,21.6,21.7,21.8,21.9,22,22.1,22.2,22.3,22.4 : REM 4500

DATA 22.5,22.6,22.7,22.8,22.9,22,23,23,23,23 : REM 4750

DATA 23,23,23,23,23,23,23,23,23,23 : REM 5000

DATA 23,23,23,23,23,23,23,23,23,23 : REM 5250

DATA 23,23,23,23,23,23,23,23,23,23 : REM 5500

DATA 23,23,23,23,23,23,23,23,23,23 : REM 5750

DATA 23,23,23,23,23,23,23,23,23,23 : REM 6000

DATA 10,10,10,10,10,10,10,10,10,10 : REM 6250

DATA 10,10,10,10,10,10,10,10,10,10 : REM 6500


DATA 10,10,10,10,10,10,10,10,10,10 : REM 6750

DATA 10,10,10,10,10,10,10,10,10,10 : REM 7000

DATA 10,10,10,10,10,10,10,10,10,10 : REM 7250

DATA 10,10,10,10,10,10,10,-10,-10,-10 : REM 7500
 
  • #47
smokingwheels said:
I personally think turbulence is the wrong way to go we are dealing with an analog device.
I think turbulence=distortion.

He's talking about getting a more homogenous charge. Which would ensure a more even and faster burn. The more turbulent the inlet flow is, the more fixed the fuel and air become.

smokingwheels said:
I think timing Before TDC is EVIL because you are compressing a rising energy eg you have to waist energy to compress the expanding gases instead of compressing a gas..Hope that makes sense.

Increasing burn rate hmm I think that would be like increasing distortion in my audio amp = not very nice. I could be wrong though.

The above is confusing and seems counter-intuative to me. Can you clarify what you mean by 'timing before TDC is evil' please.

If you allow over expansion you get a less clean and less efficient burn of the charge ni the cylinder. Ideally we would burn all the charge at the same time at a single descreeet point. However as it takes time for the flame to propogate we have to start the burn before TDC.

If you allow over expansion, you'll get incomplete combustion. Which would exlpain why you are constantly getting spark plugs caked in crap.
 
  • #48
I think it may be time to abandon the shotgun approach and impose some structure on your learning. Start with some basic engine theory books so you can see how what you're trying to do fits into the bigger picture.

I'd suggest getting "How To Make Horsepower Volume 1" by David Vizard. He presents things well and covers the essentials nicely. If you want more in-depth on how to develop a specific engine, his book "How To Modify Ford SOHC Engines" is about the Ford 2 litre 4 cylinder and the info can likely be applied to your engine. Another good book is "Power Secrets" by Smokey Yunick, again entertaining and informative. Lots more if you already have these.

If you're serious about engine theory, Heywood's "Internal Combustion Engine Fundamentals" is 900 pages worth of detailed analysis. I bought it on the recommendation of others here (was it you Chris?) and now refer to it quite frequently. Very nice having everything in one place but it may be a bit much as a starting book.

There are quite a few engine simulators (desktop dynos) that are more detailed than Turbocalc. What else are you using?

You may also find this interesting:
http://www.epi-eng.com/piston_engine_technology/thermal_efficiency.htm
 
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  • #49
russ_watters said:
This is good stuff: I have a $150 gadget that reads out my engine's operating parameters in real-time.
I have a scan gauge that plugs into the OBD2 port and shows what the ECU is doing in real time. Quite fun to play with.
 
  • #50
mender said:
Smokey Yunick

lol.
 
  • #51
xxChrisxx said:
lol.

Is that a good or a bad lol? Most recognize his contributions but wonder about the hot air engine.
 
  • #52
Ok I am learning heaps my brain hurts sometime so I stop for a coffee, after what Russ so kindly said I started to look at the data I do have.

You can grab a copy at "ftp://203.161.71.130/Engine%20Data/Raw%20Data/"[/URL] If you want the files are CITY.csv, CITY1.CSV, CITY2.CSV and CITY3.csv.

The values are at 1 second intervals and instantaneous values.
The header is RPM, time of day in seconds and vacuum advance.
If the vacuum is 20 then its above 300mm of Hg.
If the vacuum is 15 then its just below 300mm of Hg.
If the vacuum is 0 then its about 200 mm of Hg.

Then you have an idea of what I have posted on my forum [URL]http://203.161.71.130/Forum"[/URL] under fuel consumption.

I did a rough calculation last night and found from the data CITY3.CSV and the idle eg no load fuel tests I have done it only takes on an average 1.68 kw to do 40.95 km/h rear wheel power, I have no idea how good that is for a car with a dry mass of 1120 kg

What I can calculate is the fuel used at no load over the trips and then see how much is left pushing the car along over the test period also from the vacuum I maybe able to guess at fuel consumption.

Anyway I have a program to write to analyze my data from my trips this will keep me busy for a little while I can also generate an engine acceleration figure to but its uncalibrated.
 
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  • #53
I need some one to check my research notes and evidence because...

I rang the Sarich corporation and got the dyno figures for my cars mass. Thanks to them.

The dyno load for 80 km/h is 6.7 kw so at 40.95km/h = 0.5118 times less so 6.7kw * .5118 = 3.475kw there maybe some error for wind drag not in my favor?

So on average I used 1.68 kw of fuel and drove at 40.95 km/h when the load is 3.475 kw on the dyno?

Is it I have roughly double the torques with the same fuel?
I can scan my 2 pages of calculations for you to see where I may have gone wrong?

I have measure my no load fuel consumption at 3 points then worked out consumption per rpm
then used that rate at a higher rpm to get no load fuel consumption I then worked out what was left for the trip and it works out to be an average power of 2.4kw at the engine.
 
  • #54
mender said:
Is that a good or a bad lol? Most recognize his contributions but wonder about the hot air engine.

He's just funny character on the motorsports landscape.

It's almost 100% certain he was a bullgarbageter, and was mostly successfull through the tactical use of not obeying the rules. The fact that in scrutineering he always had to change something for the car to be legal (on saying that no legal car has ever won a motorrace grey areas are part of the fun) I wouldn't point to him as an example of how to change something in a scientific way though.

An interesting chap non the less.
 
  • #55
mender said:
I have a scan gauge that plugs into the OBD2 port and shows what the ECU is doing in real time. Quite fun to play with.

Thats a great idea but where would it plug into on my carby LOL!
 
  • #56
xxChrisxx said:
He's just funny character on the motorsports landscape.

It's almost 100% certain he was a bullgarbageter, and was mostly successfull through the tactical use of not obeying the rules. The fact that in scrutineering he always had to change something for the car to be legal (on saying that no legal car has ever won a motorrace grey areas are part of the fun) I wouldn't point to him as an example of how to change something in a scientific way though.

An interesting chap non the less.

Running the officials around was part of the game, but there was a solid core behind the show. His exploits tend to get mentioned more than his research though.
 
  • #57
mender said:
Running the officials around was part of the game, but there was a solid core behind the show. His exploits tend to get mentioned more than his research though.

Thanks mender maybe I should start a new thread called please explane my new toy and offer the officials one tiny bit of info at a time so as not to make them just say its impossible when hitting them with too much change.

eg why is my peak idle (no load) rpm achieved when I fire 30 - 40 degrees BTDC?
see http://203.161.71.130/forum/topic.asp?TOPIC_ID=14"
 
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  • #58
smokingwheels said:
Thanks mender maybe I should start a new thread called please explane my new toy and offer the officials one tiny bit of info at a time so as not to make them just say its impossible when hitting them with too much change.

It's becuase your problems with this are listed below. Please realize that I'm not saying this just to put you down, I don't want you to dismiss it becuase it's not what you think. I really want to help becuase I

You don't appear to know enough theory to realize what changes mean. This is evident with fairly clumsy use of numbers, calculations that don't really make sense. (Also your Carnot cycle thread shows this).
You don't appear to have a clear goal and targets for your testing regieme.
There doesn't apear to be any structure to your changes.
Unless I've missed something, you are only testing at idle. Which isn't even preresentetive of real world conditions.

The basic fact is, you are never going to get a great deal of efficiency gains out of messing with timing or fuel trim or even compression. Engines have been round for donkeys years now, you are not doing anything different to what has been done many times before.

You aren't making sweeping changes to the engine, they are relatively simple. So it's highly unrealistic to expect large changes in efficiency. As someone would have discovered and implemented it before.

You persist in that we are just doubting you. Look at the responses you've got so far in this thread and the Carnot thread. When everyone is telling you the same thing, you have to ask yourself, maybe they are right.

We can't help you with what changes to make, as you seem to have a fairly good grasp on the physical changes. We can help you to make a well structured, methodical test regieme and help interpreting results.
 
  • #59
xxChrisxx said:
It's becuase your problems with this are listed below. Please realize that I'm not saying this just to put you down, I don't want you to dismiss it becuase it's not what you think. I really want to help becuase I

You don't appear to know enough theory to realize what changes mean. This is evident with fairly clumsy use of numbers, calculations that don't really make sense. (Also your Carnot cycle thread shows this).
You don't appear to have a clear goal and targets for your testing regieme.
There doesn't apear to be any structure to your changes.
Unless I've missed something, you are only testing at idle. Which isn't even preresentetive of real world conditions.

The basic fact is, you are never going to get a great deal of efficiency gains out of messing with timing or fuel trim or even compression. Engines have been round for donkeys years now, you are not doing anything different to what has been done many times before.

You aren't making sweeping changes to the engine, they are relatively simple. So it's highly unrealistic to expect large changes in efficiency. As someone would have discovered and implemented it before.

You persist in that we are just doubting you. Look at the responses you've got so far in this thread and the Carnot thread. When everyone is telling you the same thing, you have to ask yourself, maybe they are right.

We can't help you with what changes to make, as you seem to have a fairly good grasp on the physical changes. We can help you to make a well structured, methodical test regieme and help interpreting results.

Thanks for the input

I have been working through the data and learning you are right I do not know much about the theory and most of the time I haven't a clue what is going on but I can now say I have shifted or moved the slope of the line for load vs efficiency. I now don't think I have a more efficient engine but I have moved the efficiency slope higher in the lower range so I must have taken it from some where eg my full throttle efficiency is low because my engine ingests roughly 2 times the fuel and air at high rpm eg a 2L engine consumes inexcess of 1 L/min but I would have to confirm that figure again.

I have done more calculations and compared engines for the first time in terms of efficiency of the power stroke see post under load see post #20 on this page https://www.physicsforums.com/showthread.php?t=480029&page=2"

Does anyone know of a place on the net that would list all variables I need to measure and test for the improvements I have made to my engine, oh and free?
 
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  • #60
smokingwheels said:
Does anyone know of a place on the net that would list all variables I need to measure and test for the improvements I have made to my engine, oh and free?

The efficiency of the engine is gauged by the amount of usable energy generated per unit of fuel used. You need to measure how much work the engine is doing against how much fuel it is using while doing that work - no guessing!

That's what I told you earlier. Once you are able to accurately and repeatedly measure those two things, you can start evaluating your changes.

Here's your homework:
http://autospeed.com/cms/title_Brake-Specific-Fuel-Consumption/A_110216/article.html

There will be a test.
 
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