>>any Seremban People<< N9
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- Mar 3, 2005
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SE & khoo, about the EGR thing..yesterday I tried to disable it...result was a lot of smoke from exhaust with strong fuel smell, engine dies off easily when trying to move in 1st gear...power also sucks...Then I suddenly thought of this...what causes this effect.
Petrol engine (SI = spark ignited) and diesel engine (CI = compression ignited) works differently.
For petrol the fuel is injected during the intake stroke then the air/fuel mixture is ignited. Even for TC car is the same working and petrol burns more easier than diesel.
Now diesel is a bit different because the engine only compress the air until it's temp reaches optimum combustion stage then diesel is injected then you got the power stroke. That's why diesel engine has glow plug instead of spark plug because glow plug is used to heat up the air going into the combustion chamber. So during cold starting the glow plug will glow longer to heat up the incoming air. Also diesel engine has higher compression ratio than petrol engines because as I mentioned above diesels is harder to burn so you need more heat.
When I take off the EGR, no exhaust gas circulates back into the intake manifold therefore the intake temp will be lower, when the lower intake air goes over the turbo it's temp will go up but after the intercooler it goes back down so when the air gets into the combustion chamber it might not be as hot as it used to be and the piston, metal parts..etc around will also soak up the heat so engine will die off easily when you apply load to it because when the diesel is injected the fuel can't be completely burn hence the fuel smell and more smoke. I have no problem when idle but the moment I give load to the engine it dies off. To diesel engine thermal efficiency is very important that's why diesel engine has the highest thermal efficiency compare to SI engine.
Just an example: with EGR
temp at intake: 40C
temp after compressor wheel: 300C
temp after IC:250C
temp of air at compression stroke: 480C +- with EGR valve opened. (Optimum temp for ignition)
Note: diesel engine compression ratio min is about 15:1 to 22:1 hence the higher temp.
without EGR
temp at intake: 40C
temp after compressor wheel: 300C
temp after IC:250C
temp of air at compression stroke: 330C +- without EGR valve opened. (Not optimum temp for ignition)
Above is just example of what I'm trying to say. Also with EGR on diesel the fuel that is not completely burnt can be recirculated back to be burnt again. That's why when you full throttle on diesel at you will see a lot of smoke because fuel is not completely burnt up.
1. I think the way to overcome this problem is to increase the compression ratio so that it will compensate for the loses of heat without the EGR.
2. Pre-heat the diesel before injecting it into the combustion chamber. Even the fuel is already under pressure but it's still not hot enough. I saw in Thai that they are selling diesel pre-heating device.
3. Increased the boost, but it is limited and not sure will it work because diesel's engine rev range is different from SI engines. You can take out the intercooler but the downside is you can't boost higher.
Petrol engine (SI = spark ignited) and diesel engine (CI = compression ignited) works differently.
For petrol the fuel is injected during the intake stroke then the air/fuel mixture is ignited. Even for TC car is the same working and petrol burns more easier than diesel.
Now diesel is a bit different because the engine only compress the air until it's temp reaches optimum combustion stage then diesel is injected then you got the power stroke. That's why diesel engine has glow plug instead of spark plug because glow plug is used to heat up the air going into the combustion chamber. So during cold starting the glow plug will glow longer to heat up the incoming air. Also diesel engine has higher compression ratio than petrol engines because as I mentioned above diesels is harder to burn so you need more heat.
When I take off the EGR, no exhaust gas circulates back into the intake manifold therefore the intake temp will be lower, when the lower intake air goes over the turbo it's temp will go up but after the intercooler it goes back down so when the air gets into the combustion chamber it might not be as hot as it used to be and the piston, metal parts..etc around will also soak up the heat so engine will die off easily when you apply load to it because when the diesel is injected the fuel can't be completely burn hence the fuel smell and more smoke. I have no problem when idle but the moment I give load to the engine it dies off. To diesel engine thermal efficiency is very important that's why diesel engine has the highest thermal efficiency compare to SI engine.
Just an example: with EGR
temp at intake: 40C
temp after compressor wheel: 300C
temp after IC:250C
temp of air at compression stroke: 480C +- with EGR valve opened. (Optimum temp for ignition)
Note: diesel engine compression ratio min is about 15:1 to 22:1 hence the higher temp.
without EGR
temp at intake: 40C
temp after compressor wheel: 300C
temp after IC:250C
temp of air at compression stroke: 330C +- without EGR valve opened. (Not optimum temp for ignition)
Above is just example of what I'm trying to say. Also with EGR on diesel the fuel that is not completely burnt can be recirculated back to be burnt again. That's why when you full throttle on diesel at you will see a lot of smoke because fuel is not completely burnt up.
1. I think the way to overcome this problem is to increase the compression ratio so that it will compensate for the loses of heat without the EGR.
2. Pre-heat the diesel before injecting it into the combustion chamber. Even the fuel is already under pressure but it's still not hot enough. I saw in Thai that they are selling diesel pre-heating device.
3. Increased the boost, but it is limited and not sure will it work because diesel's engine rev range is different from SI engines. You can take out the intercooler but the downside is you can't boost higher.
Last edited:
so the conclusion is dun disable it.....the benefit is more than disadvantage
http://www.youtube.com/watch?v=-5M1CUiiToc
so guys,wht the conclusion for the video above??
http://www.youtube.com/watch?v=-5M1CUiiToc
so guys,wht the conclusion for the video above??
- Mar 3, 2005
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khoo, I forgot to tell you..If you can, add an OCT to you truck...because the gases from the lubricants will re-route back into the intake and IC. after a long time, it will make the inside of the IC and intake very sticky...
About the EGR, I think people remove it mostly on older engines. I will still do some more test and see...
About the EGR, I think people remove it mostly on older engines. I will still do some more test and see...
some add on on the EGR...
it has 2 advantages for diesel engine...as we knw,its one part of the emission control thingy to reduce nitrogen oxide(NOx) emission and this is true for diesel engine...u knw la how dirty was diesel...hehe...secondly,a small quantity of hot exhaust gas in the air charge of a cold engine helps to reduce the delay period and the incidence of cold engine diesel knock...*the end*
correct me if im wrong...pasal i newbie in the progress~~~~
it has 2 advantages for diesel engine...as we knw,its one part of the emission control thingy to reduce nitrogen oxide(NOx) emission and this is true for diesel engine...u knw la how dirty was diesel...hehe...secondly,a small quantity of hot exhaust gas in the air charge of a cold engine helps to reduce the delay period and the incidence of cold engine diesel knock...*the end*
correct me if im wrong...pasal i newbie in the progress~~~~
im from jelebu actualy..but if u ok me to join..now im work at subang..i go back 2 or 1 times per month.....
can join us if u ok bro...
inform us at here when u come back frm Subang...hei jpop,whr r u??jpop frm jelebu too FarudThe Marketplace Latest
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We all love our cars & like to improve our rides (if u're not, u won't come to ZTH, right?)
I would like to know how do u measure improvement of torque & hp without putting ur car to a dyno machine..?
Especially after u bolt on some simple performance part..
Let me share how i do it 1st.. i'm not a pro.. so, my method is not exactly correct..
IDLE SPEED
the 1st thing i would do is take note what rpm my engine idle before and after i bolt on the...
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