We measure temperature INSIDE the combustion chamber (on different fuels)
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- Опубликовано: 24 июл 2024
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The results are quite a bit more interesting than some might think.
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I believe the highest temperature actually occurs in the combustion chamber, but that temperature is only there for part of the cycle, probably mostly in the power stroke. At other times during the cycle, the temps in the cylinder can be quite low. Unfortunately, the probe for the pyrometer has far too much thermal mass to indicate instantaneous temperature, so what you are reading is the average combustion chamber temperature. I would expect that engineers probably have some way to measure the actual instantaneous temperature and plot it out on a graph, but I doubt such instrumentation is easily available, and I'm quite sure it would be very far from cheap.
Regardless, it was a very interesting experiment, which is not a surprising thing at all from the garage 54 crew. These guys are always trying something interesting.
yes, and since the exhaust manifold only sees exhaust gas, the average temp will be higher there than the cylinder probe, which sees 3 strokes without combustion, plus that gulp of fresh air.
The metal surfaces won't reach the full temperature of the hot gas though, due to heat transfer coefficients.
Every combustion cycle, the chamber gets fresh air and atomized gas, that get to very low temperatures (lower than ambient) which is the reason why in the old days there were heating elements on the carburators.
Every 1/4 cycle, all that gets compressed (heats very slightly maybe), then ignited - heats a lot for most of that ignition 1/4 cycle - then exhausted in the next 1/4 cycle.
All other cycles are way more fresh than the ignition one.
Heat from combustion technically only is inside chamber for 1/4 cycle - half being burned with peak temperatures to use the force of the expanding gas, then, half being exhausted already cooling down.
On a two stroke engine the history is different as every time the piston goes up, there is a burn.
Fresh fuel and fresh air are obviously cooler, and also most engines are water cooled and those combustion chambers have coolant running through them. Exhaust manifolds are only cooled by ambient air so they will reach much higher temperatures.
This is common knowledge. Also They aren’t reading the tempature of the exhaust manifolds. Just the exhaust gas in them.. combustion chamber temperature is always lower because atomized fuel is so cold, combustion chamber would change dramatically if they added more timing, or if they removed fuel. I’d like to see the same text with methanol
No.
They runs around them , not through them.
It might be because LPG is already a gas, whereas gasoline is still a liquid vapor which takes some energy to turn into a gas which lowers the temp.
Latent heat of vaporization
@@vectorcomparison4682 exactly
💯%
On a LP fork truck its liquid LP
@@donames6941
LPG is liquid under pressure.
It doesn't enter the fuel system as a liquid.
for anyone wondering, i have once tuned e39 m54b28, on 1.3bar of boost it had like 760°C in exhaust, but on LPG on 1.5bar EGT was like 580-600° (AFR much richer) but it had more power and egt was lower :D many say lpg cracks valves and destroy engines, but if you tune it properly (with wideband O2 and also have close loop in programable ECU) its much better than regular gasoline... also LPG pressure reducer for 500hp only costs around 200€, we used stock lpg ecu and lpg injectors, so once it was tuned on programable ecu (Plug and play ecu) on gasoline, we switched to LPG and all i had to do was pull out fuel so we stay around 0.68-0.75 lambda.. due to more (mass or molecular weight) of fuel (lpg) injected, it made more boost by those 0.15-0.2bar and pulled much better due to higher boost (but low end/spool was better on gasoline, i think due to ignition timing, as lpg has higher octane it burns slower and would need few more degrees to make same torque/power in spool up)
what afr is stoichometric for lpg? also what afr should be seen under full throtle?
And safe with more boost because higher octane=no knock
One thing that pretty much everyone that doesn't understand it gets wrong when tuning LPG is that it runs cooler the leaner it is and hotter as it gets richer, along with it being critical the timing is advanced enough for lpg......i used to run my lpg subaru at around 18:1 light throttle and 16:1 wide open for 10 years without any valve or piston burning issues and egt's that were lower than it was when running on petrol.
@@unhippy1 agreed, same thing with diesel.. its hottest at stoich, and also i do know LPG get hotter with richer afr, but after some point it gets colder as there is too much lpg (also phase change from gas to liquid helps with IAT and that could be why it still has power at 0.68 lambda..
want to replicate it it some day on mine build, maybe i will do with B58 when i get one 😁
@@exvils I wasn't injecting LPG, i was carbureted via a BLOS mixer so phase change temp reductions was not something i had to deal with....and and while i was playing with it i found you lose power from being over rich long before the EGTs drop from being over rich.....lol my entire tuning setup consisted of a wideband gauge on the dash and a screwdriver (plus the extra weights i added to the flyweights in the dizzy).
The sensor being screwed into a water cooled hunk of aluminum probably has something to do with it
this is unironically one of the best engineering automotive channels out there
One thing I liked about propane setups was how clean the oil stayed. You'd always have new looking oil.
Any contaminants which make it past the air filter will discolor the oil with regular use no matter the fuel.
I drive a lpg converted air cooled vw without an oil filter. If i run gasoline, the oil is black within an hour of the engine running. On lpg, the oil gets black in a few days instead of an hour. I still change the oil every 3000 kilometers, frequent oil changes are cheaper than a rebuild. Also on the vw engine, when i run on gasoline there is a night and day difference between the exhaust smell. If i drive for a long distance on gasoline i feel the need to have a shower, on lpg there is barely any smell.
@@denizkilic6022 that's interesting. I'd run floor machines for a year without much change but you probably running a lot more fuel in the larger engine. Air cooled VW sounds pretty awesome 😎
@@eby6114 well, i actually daily drive it. Last year i did 20.000 kilometers with it, half of it is city driving and half of it is highway driving. If it weren't for lpg being available at basically every gas station in my country for less than half the price of gasoline i wouldn't be able to drive my car nearly as much. Mine is 1600cc, it can cruise at 120km/h with half throttle and it used 10 liters of lpg every 100km, which i think is pretty good for such an old car. I have to say it is a bit harder on valves, but with frequent adjustments at every second oil change its not a problem at all. Even if it were to burn a valve eventually, i can rebuild the engine myself from scratch in 2 days and i can do a half rebuild in a day so i really don't care about lpg's impact on engine life at all.
My ford tells otherwise. after 4 months of oil change and it still looks as new
If you can, do this test again but use gauges with less range so it's more responsive to small temperature increases. Enjoy your channel.
The cooler liquid should cool down the combustion chamber. The same goes for nitromethane cars. In fact nitro is so cold that you don't even need to run radiators on the drag strip
Chamber tempeture is actually much higher, but just for few miliseconds if even maybe that...
In short because there is too fast exchange of cool mixture and the hot fumes that go out of the exhaust, so the probe does not have time to read it, thats why under load you have seen the higher tempeture because at more amount of fuel the burn took much longer to push the piston back down so there was much longer higher tempeture time, thats why if you reved it the tempeture fell bacause the probe was cooled of by the cold mixture coming in.
The number that you see is an AVERAGE OF THE TEMPTURES THAT HAPPEN IN THE CYCLES , compresion and the burn is somewhere in ballpark of 600°C and the air/fuel mixture intake that can be max 50°C I would say.
Could you try this with ethanol or some gas/ethanol mixture?
Ethanol is used for its evaporative cooling effect being 3 times as strong as gasoline. And it runs richer ,stoicometic is 9:1 compared to 14.7:1 for gas so even more cooling. So remember that when adjusting the carb.
Their 100 octane fuel is probably E85 or racefuel so ethanol based, I would think.
@@martin309 100 octane doesn't say nothing about ethanol % content.
For example, in Portugal, 98 gasoline is E10. Which has 10% of ethanol.
LPG has 100 octane, but I don't think that has any ethanol in it.
So, 100% ethanol, it's a different breed!
@@BossGarage We can look at it the other way. What are the means to boost octane cheaply, in the early years of performance engines ethanol was pursued but dropped in favor of lead based with the problems that we know of.
Now honestly, I dont think racefuel would matter on an untuned non turbo lada engine ?
Thats why I think they're all similar.
I have a 1950 ford tractor that LOVES E85. You can push it way harder when mowing because of the cooling of all that extra fuel
In the 90's you could get a see through spark plug that was made with glass where normal plugs have the white ceramic .
With this glass spark plug you could tune a engine perfectly as you had a colour chart to for correct burning and you could check if all cylinders got the same air and fuel mixture . This colour chart also state what the combustion chamber temperature could be . A blue colour was the near ideal combustion flame
Your channel is awesome! I am so glad I accidentally found it.
I used to work on Propane converted vehicles, there is no lubricating or cooling properties to Propane, and its hot burning so if you didn't replace the exhaust valve seats the valves would wind up sinking 6-8 mm into the heads.
🎉 Proof of thermal dynamic efficiencies 😂
Adjust the ignition timing so that you get a large amount of pre-ignition knock then check the temperatures again
I think the exhaust temp is 2x hotter than internal temperature because in the engine, there's oil and coolant, cooling the engine. When it comes out of the exhaust, there's little to no air cooling it off, so it's hotter than the internal temperature
Now do diesel please
Glow plugs won’t be as exciting… they’re the foundation to diesel.
@@BritishEngineer explain, i thought glow plugs were just for starting a diesel engine
@@thepalmshop239 you are indeed right. Not everyone knows it 😂
@@thepalmshop239only in cold weather, Diesel just needs compression
@@BritishEngineervery high diesel fuel pump and injector pressures and compression are the foundations of diesel. Glow plugs are a starting assist only. Once your diesel engine is warm, you can just start it without glowing the plugs.
My 6.5L Turbo dieselSuburban would hit 1200-1300 EGTs when towing uphill.
Try balancing a car while driving with only two wheels - front right and rear left or front left and rear right.
Try making brake shoes which make contact with the tread on the tires, and test stopping distance against disc braking. This is how some minibikes have their braking set up.
I have a Fiat 125. Year 1968. soo i love your Lada
Excellent video! Is your version of 100 octane oxygenated? If so, a simple carburetor engine with no λ feedback will tend to run a little lean.
LPG as far as I know works different than gasoline. The richer the mixture, the higher the temps. Maybe your rigged LPG feed was running lean, because burnt exhaust valves (and seats) from LPG are a fact. Factory LPG systems have different valves, seats etc.
For a video idea, take a stock Lada engine, maybe a 1.7 injected from a NIVA, and freshen it up so that it is in good working condition. Add a turbo and extra fuel so that the mixture is close to correct and take it to a dyno. Add boost and fuel till it goes pop and measure the results!
Cheers from Greece
Solid!
Top KEK!
Peace be with you.
Lpg needs to be boiled in order to be expanded.
Hence why lpg cars have a vaporiser or expander which is connected to the cars cooling system, the temperature from the coolant causes the gases to expand.
Usually the gas would be directed into the intake via a servo actuator.
I could tell you a lot more, but I'll leave this here, also lpg burns much hotter, hence why we need to use flashlube to prevent head cracks and valve damage.
Exhaust only has hot gases flowing through it, while the combustion chamber is pulling in cool fresh air regularly- it makes sense that the chamber is cooler than the exhaust.
Quality content as usual, doing all the things that other channels do not want or do not think of doing. Keep up the good work!
Would love to see how higher compression / fuel injection / turbo / ethanol affect the temperatures. I can obviously guess already but how much do they affect? Maybe an idea for a future episode?
Answering questions that I never even knew I had. Great channel
Messing with the ignition advance would probably show more temperature increases than just different fuel.
I had 3 times valves burning up on my 1.4S carburated car due to the mechanical advance not working correctly. Only the vacuum controlled advance was working.
Exhaust valve overheated and melted away on one spot. Did it on regular gas or LPG.
Cooling system was ok.
Changed the ignition assembly and it never burned valves again.
The combustion chamber is way way hotter but only during some parts of the thermodynamic cycle as fresh air and fuel cool it up. The reason to the meter not going up is it's mass, as it doesn't have time to get to temp between the different steps of the cycle, and that's why actual combustion temps are almost only studied in laboratories and modern cars don't have sensors there. Even with a smaller sensor it would still be nearly impossible to capture such quick changes
Internal combustion engines are actually powered by pressure not heat. If you measure pressure in the cylinder, on the compression stroke you might get about 120 psi, on the power stroke the pressure in the cylinder can increase anywhere from 2 to 20 times and this increase in pressure is directly proportional to power ( more pressure, more power )
Ooooooooohhhhhh this is exciting!
This was a very interesting test. I've always wondered about the temperatures. Would love to see you guys try this test on a diesel engine.
Gotta put that onna E.F.I. Lada!!!
...compressing propane to achive 50lbs???
Sounds like something to watch from another continent!!!
If they want, i can sponsor the BossECU 💯💯💯
i don't know if you have done this already, but you should try running a engine upside down.
ALso remember, when the cylinder goes down to draw fuel, a vacuum is created. Vacuum creates cold, and cold, along with the cold fuel mixture - makes the CHT give it's cold reading.
CHT? FORD CHT?
@@gabrielv.4358 CHT = Cylinder Head Temperature.
This is maybe a new video series idea. Often i think about running different motors with different working areas with some "other sort" of fuel. Not only the temperature is interesting, also the power output would be.
Excellent as usual. But I am wondering if the combustion chamber egt reads low because it was surrounded by coolant.
That thing is making a lada smoke
That's a dang gud cooling system for the combustion chamber to remain below 250°c
The egt sensor in the combustion chamber is loosing heat to the cylinder head and water jacket, that's why it reads lower. The gas temperature inside the combustion chamber is higher than inside the exhaust manifold
The AFR for LPG was uncontrolled. The higher the revs, the leaner it became. And lean combustion = higher temperatures
Think about it... you have cool air and gas (which is atomizing and cooling the charge more) so the cumbustion chamber is getting cooled every intake stroke (and exhaust stroke) power and compression it will go up. also the head is water cooled... so it is not going to change much you'll need something faster than that EGT sensor
The gas cilinder on the passenger side.
What can possible go wrong?
Crazy Russians 😂😂😂
I love these more scientific videos!
That was amazing
hook the egt sensors readings into a computer so the temps can be charted and graphed and printed out. good video
should have run the ignition timing forward and back to see how at affects both temperatures. Also should have like towed another dead lada or taken it to the testing area so they could have put an actual load on the engine
An interesting experiment
Interesting experiment
Would love to know if a sprayed in liquid form LPG injector for port injection would work better in expending heat energy during expansion into a vapor to drop intake temps even lower. Or direct injection. With tuning for timing to drop it further. The colder the combustion chamber is the better it is for power. Generally though, you can think of it this way, half the time is used intaking, the other half exhausting. Because fuel is used, that absorbs extra heat. So it should, typically, be less than half the temp of the exhaust.
Kinda. Fuel timing and types can massively change temps, same for how fuel is delivered and the temp of the air coming in. If it's cooled just before or well before. Both change that as heat soak can happen.
its interesting that combustion chamber temp increase more while under load. So going uphill will overheat the engine quicker everytime.
Likely, the vaporization of the LPG is done in the tank. Therefore, they are not any change of phase occurring in the cylinder.
Alcohol(stoich ratio 9.8 for E85. 9.0 for E100) would reduce temperature inside the combustion chamber more significantly.
I'd be curious on the temperature increases with an increase in compression, both in the combustion chamber and the EGT. I feel it would be a decent difference especially with higher octane fuels.
I'm glad they have English translation for Americans to watch the fun experiments
And now test the different timing degrees and see how it affect the temperature in the combustion chamber❤
Put a snail on dat
I'd like to see the same test but measuring the temperature in the catalytic convertor.
LPG is about 110 octane and maybe also because its burning that much slower, it let's out more heat overall during the slow combustion.
You should test those coolant additives that claim to reduce combustion temps. Like cool down and water wetter
The liquid fuel has a cooling property, when you compress fuel and turn it into a vapor it releases heat, if you compressed it enough it would explode, like diesel.... The lpg is already a vapor, so think of it like getting spritzed by a spray bottle VS getting a cup of water poured on you.
Test again with NGK LPG Laserline spark plugs. These have reduced gaps (0.6mm). NGK claims that temps will be lowered if this spark plug used.
Did they plumb the propane directly into the bowl? 😂😂😂💀
higher octane rating = better resistance of the fuel to ignition. Logically, this means that if you dont touch the ignition advance (by the distributor cap in this case) the result will be: more fuel left to burn in the exhaust (after the exhaust valve), when used 95 octane compared to the 92 octane. This is proved when you saw that with 95 octane there was higher exhaust manifold temperature. So the test can not be qualified as accurate. The ignition advance had to be adjusted (advanced by the >correct!< degrees, not just 'some' degrees' by guess)
Is rolf engine oil any good ?
I think this needed to be tested somewhere with a long hill so the car was wide open throttle for a while, im pretty sure this would have increased the cylinder temperature quite dramatically.
AWESOME
I wonder what the temps would be if you ran the engine on Vodka
😎
The difference in temp is a lot different because you have put senzor underneath intake valve, fresh mixture constantly cooling sensor
Gaseous fuels do no "refresh" the combustion chamber (that's why engines that burn LPG or Methan must have stronger valves and use special oil)
the combination will result in ReckGass
You guys should look at exhaust temps running on oxy acetylene. LOL
my egt reads 550C upon start up then stabilises at 475C at idle and 750C WOT for a pushrod v8 mild cam
Also the head is refrigerated and heat has more surface to dissipate
12 seconds in, did you carpet a Lada? xD
You should do a burnout and watch the temperature rise
Would the engine tempura be lower because of the raider cooling the engine block?
I’d love to see youse fellas make a single cylinder engine from a lada engine. Then gear it down so it can drive
Is Rolf any good? 🤔🤔🤔 Who has reviewed it?
You should measure the temperature inside the combustion chambers when you make pistons out of tungsten!
How if you add some ethanol to the gasoline?
I’d like to see these same tests on a turbocharged and naturally aspirated car
95 octane "mid grade" wild to hear from west coast USA, lol
Content idea. Trailer tires vs passenger car tires. Accelerate, breaking and cornering.
Engine block is cooled, but exhaust pipe is not. That is the difference
Why not add more timing on 100 and see the effects on combustion chamber temp vs egt. You should see a significant change even with 3-4 degrees of ignition timing.
Unfortunately the merch store is not available from Germany :(
So, after all that. Why lpg eating the valve seats?
the combustion chamber is kept cooler by coolant
I have idea make upside down suspension in lada
I think the short-term future, until we get enough electricity and liquid hydrogen, Is going to be Direct cylinder injection of liquid propane The setup in the video probably evaporates the propane In the regulator. Note that propane has an extremely high ignition temperature So extremely high compression ratios can be used Mitigating the lower Energy density.
Please do an experiment putting propane gas under the air filter to boost power
I'm high and i was wondering what would happen if you use gasoline instead of antifreeze and run the engine for a longer time?
Consider making the Lata operate on Hydrogen (H2), in other words, run solely on water without any gasoline, make video of it. Thanks
Is it also because you passed the thermocouple through a coolant port?
Cold air & gasoline lower combustion chamber temperature…btu are absorbed in the air and fuel vapor
what about ethanol?
So here is an idea instead of a turbo forcing air in a motor try pulling out the exhaust faster like a exhaust turbo sucking the exhaust out the engine....still should boost power under more air in and out is more power ?
Your ignition timing was a bit late perhaps.
Time it earlier and the combusion chamber temps will rise.
Great way to fine-tune ignition timing actually.
It would be nice to check in a car with A/C (if you haven't already) whether propane (LPG) can easily replace ANY other refrigerant gas in a car air conditioner.
It would be interesting to see what happens when you lean out the cylinder. It will obviously get hotter but how hot?
we cannot even get 100 octane here :( .. I would like to see what the temps are right after turning off the engine and it heatsoaks.