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View Full Version : Study of Engine Cooling Technologies for knock supression



Skiracer
12-11-2005, 09:29 PM
If someone could translate this to english, i'd be greatful:
http://www.mitsubishi-motors.com/corporate/about_us/technology/review/e/pdf/2004/16E_04.pdf

EVOla_VIRUS
12-11-2005, 10:02 PM
Reducing the exhaust gas temperature will enable the engine to run cooler thus reduce the possibility of predetonation. They looked at intensifying the cooling of the cyl head, block, and pistons. From what was done, they were able to extract 4deg of ignition timing (adv).

As far as performance, they proposed to thin out the combustion chamber walls, insert cooling slits between cylinders, and cooling effects on the pistons using different conditions of the aforementioned proposed.

Oh, and "CA" in that report refers to Crankshaft Angle...in case someone asks ;)

rammsteinmatt
12-11-2005, 10:04 PM
lemme read it

ok, from what i gather:

statement - reducing gas temperature after the combustion stage (exhaust) will supress knock

solution - placing "cooling ducts" in the block itself which will cool the metal of the block, which will reduce the temperature of the gas (air / fuel) pre combustion. essentially when the fuel (air / fuel) is intake by the cylinder the heat of the block (from previous combustions) begins to heat the fuel, coupled with the heating caused by compression, the fuel is quite hot. say the combustion temp is equal to the intake temp + heat transfer temp + compression heat, therefore we have: Tb = Tsu + Th + Tsq (temp bang = temp suck + temp heat transfer + temp squish; from: suck, squish, bang, blow - otto cycle)

therefore by cooling the block we can reduce (Th) and therefore reduce Tb. if Tbrevised is lower than Tbstandard and goes through the same combustion stage, then we can assume Tb will be lower. a lower Tb suports our original assertion that lower Tb will supress knock

entiendes?

however, as an engineer, you must also think practically. can the block take normal (or raised) boost levels if all these caverns are drilled into the block? sure no knock would be nice, but would you turn down the boost for the sake of it? no.

Coolguy949
12-11-2005, 10:52 PM
can the block take normal (or raised) boost levels if all these caverns are drilled into the block? sure no knock would be nice, but would you turn down the boost for the sake of it? no.


that's why a good intercooler, or even alchy/water injection (a whole 'nother can of worms debate) would successfully lower the temps enough to make big power without knock. Mitsubishi should just enlarge the turbo instead of making all these cooling passages. Larger turbo will generate the same power at a lower duty cycle, creating less heat.

rammsteinmatt
12-11-2005, 11:27 PM
can the block take normal (or raised) boost levels if all these caverns are drilled into the block? sure no knock would be nice, but would you turn down the boost for the sake of it? no.


that's why a good intercooler, or even alchy/water injection (a whole 'nother can of worms debate) would successfully lower the temps enough to make big power without knock. Mitsubishi should just enlarge the turbo instead of making all these cooling passages. Larger turbo will generate the same power at a lower duty cycle, creating less heat.


but there would be more lag, and people would complain (not me, however). if there was some ducting directing air at the hotside to help coo............um, pretend you didnt hear that, i've got a great idea. be back in a couple days O0

Coolguy949
12-11-2005, 11:38 PM
Well, not that much bigger. Kinda of like a white rabbit or something.

Miss Evo8
12-12-2005, 03:39 AM
Do you think it would be worth it to get a better radiator/ fan and low temp thermostat to lower overall engine temps? Would that result in lower egt's?

gen4k20a2
12-12-2005, 09:35 AM
I thought the turbo WAS larger in the IX's?? :?

turbolarry
12-12-2005, 01:10 PM
if there was some ducting directing air at the hotside to help coo............um, pretend you didnt hear that, i've got a great idea.* be back in a couple days* O0


But also keep in mind the cooler the exhaust temp.'s, the less it will flow, hot gasses flow better.* Insulate the turbine housing, O2 housing, and downpipe; Keep that heat contained and flowing.
Then cool the intake charge; ducting to the intercooler (raise it's efficency), insulate all the intake piping, cold air intake.* (Yes, I've heard all the CAI debates; 10* cooler going into a turbo means 10* cooler coming out of the turbo.)

rammsteinmatt
12-12-2005, 02:24 PM
Do you think it would be worth it to get a better radiator/ fan and low temp thermostat to lower overall engine temps? Would that result in lower egt's?


yes, presumably yes

get an electric fan from RRE and screw it to the hood vent (so it pushes air out)
seems like a good idea to get heat out, you would also theoretically increase front downforce ;)

trannb
12-12-2005, 04:22 PM
Mitsubishi should just enlarge the turbo instead of making all these cooling passages. Larger turbo will generate the same power at a lower duty cycle, creating less heat.

This is not always a practical answer if you attack the problem from a WRC/Group N perspective. They may have some serious limitations that we just don't know about.

rsmatt
12-12-2005, 06:56 PM
the motorcycle crowd has been doing this for a long time, or rather understood it and tried to modify the head to get better results. by modifying the head ( intake/exhaust port placment and squish band ) you can gain power by getting a more favorable swirl and lower piston/head surface temps witch for internal combustion engine means higher compresion and more timing. also in the bikes they found that piston dome/dish played a major part in the numbers.
worth note is the word ceramic O0. you want to isolate the heat from combustion? try ceramics :D.

rsmatt
12-12-2005, 07:07 PM
here is a link* you might want to check out http://www.popsci.com/popsci/futurecar/19b09aa138b84010vgnvcm1000004eecbccdrcrd/2.html

who wants to build a custom head and be rich? i have squish experience with bikes and access to but loads of motocross race head r&d just ripe for the taking, who's with me?* 8) lol

Knower
12-20-2005, 06:50 PM
Do you think it would be worth it to get a better radiator/ fan and low temp thermostat to lower overall engine temps? Would that result in lower egt's?


Your "stock" radiator fan is better than most aftermarket radiator fans. The only reason to replace it is if you have space restrictions from a turbo/radiator upgrade. Even then you should try to mimick the shrouding designed into the stock fan.

A lower temperature thermostat will just make your ECU think you are not up to temperature and you'll get lower power than stock.

I think all that is definitely worth it. You should definitely spend money and time to make your car worse than stock. O0

GokuSSJ4
12-21-2005, 01:50 AM
Do you think it would be worth it to get a better radiator/ fan and low temp thermostat to lower overall engine temps? Would that result in lower egt's?


Your "stock" radiator fan is better than most aftermarket radiator fans. The only reason to replace it is if you have space restrictions from a turbo/radiator upgrade. Even then you should try to mimick the shrouding designed into the stock fan.

A lower temperature thermostat will just make your ECU think you are not up to temperature and you'll get lower power than stock.

I think all that is definitely worth it. You should definitely spend money and time to make your car worse than stock. O0

can this be an alternative route for those that do road race, or at least i can think that running cooler at a road race coarse can always benefit from it, correct ?

leaveit2bevo
12-21-2005, 12:16 PM
Do you think it would be worth it to get a better radiator/ fan and low temp thermostat to lower overall engine temps? Would that result in lower egt's?


Your "stock" radiator fan is better than most aftermarket radiator fans. The only reason to replace it is if you have space restrictions from a turbo/radiator upgrade. Even then you should try to mimick the shrouding designed into the stock fan.

A lower temperature thermostat will just make your ECU think you are not up to temperature and you'll get lower power than stock.

I think all that is definitely worth it. You should definitely spend money and time to make your car worse than stock. O0

can this be an alternative route for those that do road race, or at least i can think that running cooler at a road race coarse can always benefit from it, correct ?


I think orlando is saying it will make the car worse not better

Terry S
12-21-2005, 01:18 PM
here is a link* you might want to check out http://www.popsci.com/popsci/futurecar/19b09aa138b84010vgnvcm1000004eecbccdrcrd/2.html

who wants to build a custom head and be rich? i have squish experience with bikes and access to but loads of motocross race head r&d just ripe for the taking, who's with me?* 8) lol


Interesting article. I'd like to see this guys "scratches" applied to some old beater 4G63.. O0

Terry S

trinydex
02-27-2006, 09:28 PM
can the block take normal (or raised) boost levels if all these caverns are drilled into the block? sure no knock would be nice, but would you turn down the boost for the sake of it? no.


that's why a good intercooler, or even alchy/water injection (a whole 'nother can of worms debate) would successfully lower the temps enough to make big power without knock. Mitsubishi should just enlarge the turbo instead of making all these cooling passages. Larger turbo will generate the same power at a lower duty cycle, creating less heat.


but there would be more lag, and people would complain (not me, however). if there was some ducting directing air at the hotside to help coo............um, pretend you didnt hear that, i've got a great idea. be back in a couple days O0

not following why you'd cool the hotside...

Knower
03-02-2006, 05:59 PM
not following why you'd cool the hotside...


Holy old thread back from the dead batman!

That IS pretty funny. Akin to the lower thermostat idea. :)